MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Hearing Research' source. Tue, 07 Feb 2012 05:01:19 +0100 http://www.medworm.com/index.php?rid=5621564&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22240459%26dopt%3DAbstract Authors: Nityananda V, Bee MA Abstract Humans and other animals often communicate acoustically in noisy social groups, in which the background noise generated by other individuals can mask signals of interest. When listening to speech in the presence of speech-like noise, humans experience a release from auditory masking when target and masker are spatially separated. We investigated spatial release from masking (SRM) in a free-field call recognition task in Cope's gray treefrog (Hyla chrysoscelis). In this species, reproduction requires that females successfully detect, recognize, and localize a conspecific male in the noisy social environment of a breeding chorus. Using no-choice phonotaxis assays, we measured females' signal recognition thresholds in response to a target signal ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5621564 Sun, 08 Jan 2012 05:00:00 +0100 5621564 http://www.medworm.com/index.php?rid=5621555&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22245715%26dopt%3DAbstract Authors: Snow JB Abstract The Tinnitus Research Consortium (TRC) is sponsored by a philanthropist who wants to accelerate progress in basic and clinical research on tinnitus. The TRC consists of 12 distinguished auditory scientists who began meeting in 1998 twice a year for brainstorming for new research approaches to tinnitus, developing requests for applications, judging the scientific merit of the applications received and reviewing the progress of funded projects. Through these efforts, common confounding variables in tinnitus research have been identified, and solutions to these problems have been suggested. TRC grants have been made up to $100,000.00 per year for three years. The sponsor had provided $600,000.00 per year; so two new grants could be made each year. The good ne... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5621555 Sun, 08 Jan 2012 05:00:00 +0100 5621555 http://www.medworm.com/index.php?rid=5621566&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22234161%26dopt%3DAbstract Authors: Viola FC, De Vos M, Hine J, Sandmann P, Bleeck S, Eyles J, Debener S Abstract Electrical artifacts caused by the cochlear implant (CI) contaminate electroencephalographic (EEG) recordings from implanted individuals and corrupt auditory evoked potentials (AEPs). Independent component analysis (ICA) is efficient in attenuating the electrical CI artifact and AEPs can be successfully reconstructed. However the manual selection of CI artifact related independent components (ICs) obtained with ICA is unsatisfactory, since it contains expert-choices and is time consuming. We developed a new procedure to evaluate temporal and topographical properties of ICs and semi-automatically select those components representing electrical CI artifact. The CI Artifact Correction (CIAC) algorit... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5621566 Thu, 05 Jan 2012 05:00:00 +0100 5621566 http://www.medworm.com/index.php?rid=5621567&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22230370%26dopt%3DAbstract Authors: Landsberger DM, Padilla M, Srinivasan AG Abstract Cochlear implant performance in difficult listening situations is limited by channel interactions. It is known that partial tripolar (PTP) stimulation reduces the spread of excitation (SOE). However, the greater the degree of current focusing, the greater the absolute current required to maintain a fixed loudness. As current increases, so does SOE. In experiment 1, the SOE for equally loud stimuli with different degrees of current focusing is measured via a forward-masking procedure. Results suggest that at a fixed loudness, some but not all patients have a reduced SOE with PTP stimulation. Therefore, it seems likely that a PTP speech processing strategy could improve spectral resolution for only those patients with a reduc... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5621567 Wed, 04 Jan 2012 05:00:00 +0100 5621567 http://www.medworm.com/index.php?rid=5621559&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22245714%26dopt%3DAbstract Authors: Zhou N, Xu L, Pfingst BE Abstract The ability of an implanted ear to integrate multiple pulses, as measured by the slopes of detection threshold level (T level) versus pulse rate functions, may reflect cochlear health in the cochlea, as suggested by previous animal studies (Kang et al., 2010; Pfingst et al., 2011). In the current study, we examined the slopes of T level versus pulse rate functions in human subjects with cochlear implants. Typically, T levels decrease as a function of pulse rate, consistent with a multipulse integration mechanism. The magnitudes of the slopes of the T level versus pulse rate functions obtained from the human subjects were comparable to those reported in the animal studies. The slopes varied across stimulation sites, but did not change sys... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5621559 Wed, 04 Jan 2012 05:00:00 +0100 5621559 http://www.medworm.com/index.php?rid=5621565&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22240458%26dopt%3DAbstract Authors: Chen FQ, Hill K, Guan YJ, Schacht J, Sha SH Abstract Aminoglycoside antibiotics and cisplatin (CDDP) are the major ototoxins of clinical medicine due to their capacity to cause significant, as well as permanent hearing loss by targeting the mammalian sensory cells. Understanding the pathogenesis of damage is the first step in designing effective prevention of drug-induced hearing loss. In-vitro systems greatly enhance the efficiency of biochemical and molecular investigations through ease of access and manipulation. HEI-OC1, an inner ear cell line derived from the immortomouse, expresses markers for auditory sensory cells and, therefore, is a potential tool to study the ototoxic mechanisms of drugs like aminoglycoside antibiotics and CDDP. HEI-OC1 cells (and also HeLa cell... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5621565 Sat, 31 Dec 2011 05:00:00 +0100 5621565 http://www.medworm.com/index.php?rid=5578152&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22226928%26dopt%3DAbstract The objective of this paper is to consider the available cues that are degraded in different ways when a cochlear implant is combined with a contralateral hearing aid or second implant, and to review the literature in that context. It is found that the data largely confirm the expectations that arise from those considerations, and that outcomes differ substantially for the two types of listeners, with a greater emphasis on better ear selection and comparison of information at the two ears for bilateral implant users, and conversely, on the complementary use of information from the two ears in bimodal listeners. PMID: 22226928 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5578152 Fri, 30 Dec 2011 05:00:00 +0100 5578152 http://www.medworm.com/index.php?rid=5578153&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222235%26dopt%3DAbstract Authors: Kundu S, Munjal C, Tyagi N, Sen U, Tyagi AC, Tyagi SC Abstract More than 29 million adults in the United States have been diagnosed with hearing loss. Interestingly, elevated homocysteine (Hcy) levels, known as hyperhomocysteinemia (HHcy), are also associated with impaired hearing. However, the associated mechanism remains obscure. The collagen receptor such as discoidin domain receptor 1 and matrix metalloproteinase (MMP) play a significant role in inner ear structure and function. We hypothesize that HHcy increases hearing thresholds by compromise in inner ear vasculature resulted from impaired Hcy metabolism, increased oxidative stress, collagen IVa and collagen Ia turnover. The treatment with folic acid (FA) protects elevated hearing thresholds and prevents reduction i... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5578153 Sat, 24 Dec 2011 05:00:00 +0100 5578153 http://www.medworm.com/index.php?rid=5549872&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200608%26dopt%3DAbstract Authors: Banai K, Fisher S, Ganot R Abstract Non sensory factors such as stimulus context and musical experience are known to influence auditory frequency discrimination, but whether the context effect extends to auditory temporal processing remains unknown. Whether individual experiences such as musical training alter the context effect is also unknown. The goal of the present study was therefore to investigate the effects of stimulus context and musical experience on auditory temporal-interval discrimination. In experiment 1, temporal-interval discrimination was compared between fixed context conditions in which a single base temporal interval was presented repeatedly across all trials and variable context conditions in which one of two base intervals was randomly presented on ea... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5549872 Tue, 20 Dec 2011 05:00:00 +0100 5549872 http://www.medworm.com/index.php?rid=5549874&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22197852%26dopt%3DAbstract Authors: Hornickel J, Knowles E, Kraus N Abstract The click-evoked auditory brainstem response (ABR) is widely used in clinical settings, partly due to its predictability and high test-retest consistency. More recently, the speech-evoked ABR has been used to evaluate subcortical processing of complex signals, allowing for the objective assessment of biological processes underlying auditory function and auditory processing deficits not revealed by responses to clicks. Test-retest reliability of some components of speech-evoked ABRs has been shown for adults and children over the course of months. However, a systematic study of the consistency of the speech-evoked brainstem response in school-age children has not been conducted. In the present study, speech-evoked ABRs were collected... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5549874 Fri, 16 Dec 2011 05:00:00 +0100 5549874 http://www.medworm.com/index.php?rid=5549873&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200607%26dopt%3DAbstract Authors: Drummond MC, Belyantseva IA, Friderici KH, Friedman TB Abstract Hereditary deafness is genetically heterogeneous such that mutations of many different genes can cause hearing loss. This review focuses on the evidence and implications that several of these deafness genes encode actin-interacting proteins or actin itself. There is a growing appreciation of the contribution of the actin interactome in stereocilia development, maintenance, mechanotransduction and malfunction of the auditory system. PMID: 22200607 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5549873 Tue, 13 Dec 2011 05:00:00 +0100 5549873 http://www.medworm.com/index.php?rid=5534593&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22186087%26dopt%3DAbstract Authors: Salih WH, Buytaert JA, Aerts JR, Vanderniepen P, Dierick M, Dirckx JJ Abstract High-resolution 3D morphology models of cat, gerbil, rabbit, rat and human ossicular chains are presented. The models are based on high-resolution CT measurements. The resolution of the CT images, from which the models are segmented, varies from 5.6 to 33.5 μm. Models are freely available in different formats at our website (http://www.ua.ac.be/bimef/models) for research and educational purposes. PMID: 22186087 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534593 Tue, 13 Dec 2011 05:00:00 +0100 5534593 http://www.medworm.com/index.php?rid=5534594&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22183155%26dopt%3DAbstract Authors: Buck LM, Winter MJ, Redfern WS, Whitfield TT Abstract The ototoxicity of a number of marketed drugs is well documented, and there is an absence of convenient techniques to identify and eliminate this unwanted effect at a pre-clinical stage. We have assessed the validity of the larval zebrafish, or more specifically its lateral line neuromast hair cells, as a microplate-scale in vivo surrogate model of mammalian inner ear hair cell responses to ototoxin exposure. Here we describe an investigation of the pathological and functional consequences of hair cell loss in lateral line neuromasts of larval zebrafish after exposure to a range of well known human and non-human mammalian ototoxins. Using a previously described histological assay, we show that hair cell damage occurs i... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534594 Sun, 11 Dec 2011 05:00:00 +0100 5534594 http://www.medworm.com/index.php?rid=5534595&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22178982%26dopt%3DAbstract Authors: Du X, Chen K, Choi CH, Li W, Cheng W, Stewart C, Hu N, Floyd RA, Kopke RD Abstract The purpose of this study was to reveal synaptic plasticity within the dorsal cochlear nucleus (DCN) as a result of noise trauma and to determine whether effective antioxidant protection to the cochlea can also impact plasticity changes in the DCN. Expression of synapse activity markers (synaptophysin and precerebellin) and ultrastructure of synapses were examined in the DCN of chinchilla 10 days after a 105 dB SPL octave-band noise (centered at 4 kHz, 6 h) exposure. One group of chinchilla was treated with a combination of antioxidants (4-hydroxy phenyl N-tert-butylnitrone, N-acetyl-l-cysteine and acetyl-l-carnitine) beginning 4 h after noise exposure. Down-regulated synaptophysin and p... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534595 Fri, 09 Dec 2011 05:00:00 +0100 5534595 http://www.medworm.com/index.php?rid=5534597&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22178980%26dopt%3DAbstract Authors: Lee J, Long G Abstract When hearing thresholds are measured with high-frequency resolution there is a pseudo-periodic variation in thresholds across frequency of up to 15-20dB. This variation is called threshold fine structure (previously referred to as threshold microstructure). Consequently, estimates of auditory status based on threshold measures can depend greatly on the specific frequency evaluated. The impact of threshold fine structure on the prediction of auditory status was examined by measuring detection thresholds of pure tones (providing an indication of threshold fine structure) and comparing them with thresholds obtained using linear sweeps, sinusoidally frequency modulated tones, and narrow-band noise. Spontaneous otoacoustic emissions (SOAEs) were also obta... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534597 Thu, 08 Dec 2011 05:00:00 +0100 5534597 http://www.medworm.com/index.php?rid=5534596&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22178981%26dopt%3DAbstract Authors: Salt AN, King EB, Hartsock JJ, Gill RM, O'Leary SJ Abstract It has been widely believed that drug entry from the middle ear into perilymph occurs primarily via the round window (RW) membrane. Entry into scala vestibuli (SV) was thought to be dominated by local, inter-scala communication between scala tympani (ST) and SV through permeable tissues such as the spiral ligament. In the present study, the distribution of the ionic marker trimethylphenylammonium (TMPA) was compared following intracochlear injections or applications to the RW niche, with or without occlusion of the RW membrane or stapes area. Perilymph TMPA concentrations were monitored either in real time with TMPA-selective microelectrodes sealed into ST and SV, or by the collection of sequential perilymph sampl... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534596 Thu, 08 Dec 2011 05:00:00 +0100 5534596 http://www.medworm.com/index.php?rid=5534599&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22154930%26dopt%3DAbstract Authors: Xu N, Engbers J, Khaja S, Xu L, Clark JJ, Hansen MR Abstract Regrowth of peripheral spiral ganglion neuron (SGN) fibers is a primary objective in efforts to improve cochlear implant outcomes and to potentially reinnervate regenerated hair cells. Cyclic adenosine monophosphate (cAMP) regulates neurite growth and guidance via activation of protein kinase A (PKA) and Exchange Protein directly Activated by Cylic AMP (Epac). Here we explored the effects of cAMP signaling on SGN neurite length in vitro. We find that the cAMP analog, cpt-cAMP, exerts a biphasic effect on neurite length; increasing length at lower concentrations and reducing length at higher concentrations. This biphasic response occurs in cultures plated on laminin, fibronectin, or tenascin C suggesting that it ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534599 Sat, 03 Dec 2011 05:00:00 +0100 5534599 http://www.medworm.com/index.php?rid=5534600&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22146425%26dopt%3DAbstract Authors: Fraser M, McKay CM Abstract Temporal modulation transfer functions (TMTFs) were measured for six users of cochlear implants, using different carrier rates and levels. Unlike most previous studies investigating modulation detection, the experimental design limited potential effects of overall loudness cues. Psychometric functions (percent correct discrimination of modulated from unmodulated stimuli versus modulation depth) were obtained. For each modulation depth, each modulated stimulus was loudness balanced to the unmodulated reference stimulus, and level jitter was applied in the discrimination task. The loudness-balance data showed that the modulated stimuli were louder than the unmodulated reference stimuli with the same average current, thus confirming the need to lim... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534600 Fri, 02 Dec 2011 05:00:00 +0100 5534600 http://www.medworm.com/index.php?rid=5534598&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22155337%26dopt%3DAbstract In this study, the contribution of the piston-like and rocking-like components of the stapes motion to cochlea activation was quantitatively investigated with measurements in live guinea pigs and a related mathematical description. The isolated stapes in anesthetized guinea pigs was stimulated by a three-axis piezoelectric actuator, and 3-D motions of the stapes and compound action potential (CAP) of the cochlea were measured simultaneously. The measured values were used to fit a hypothesis of the CAP as a linear combination of the logarithms of the piston-like and rocking-like components. Both the piston-like and rocking-like components activate cochlear responses when they exceed certain thresholds. These thresholds as well as the relation between CAP and intensity of the motion componen... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534598 Fri, 02 Dec 2011 05:00:00 +0100 5534598 http://www.medworm.com/index.php?rid=5534601&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22146424%26dopt%3DAbstract Authors: Arch VS, Simmons DD, Quiñones PM, Feng AS, Jiang J, Stuart BL, Shen JX, Blair C, Narins PM Abstract Three species of anuran amphibians (Odorrana tormota, Odorranalivida and Huia cavitympanum) have recently been found to detect ultrasounds. We employed immunohistochemistry and confocal microscopy to examine several morphometrics of the inner ear of these ultrasonically sensitive species. We compared morphological data collected from the ultrasound-detecting species with data from Rana pipiens, a frog with a typical anuran upper cut-off frequency of ∼3 kHz. In addition, we examined the ears of two species of Lao torrent frogs, Odorranachloronota and Amolops daorum, that live in an acoustic environment approximating those of ultrasonically sensitive frogs. Our results sug... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534601 Fri, 25 Nov 2011 05:00:00 +0100 5534601 http://www.medworm.com/index.php?rid=5534603&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22138310%26dopt%3DAbstract Authors: Kane KL, Longo-Guess CM, Gagnon LH, Ding D, Salvi RJ, Johnson KR Abstract Inbred strain variants of the Cdh23 gene have been shown to influence the onset and progression of age-related hearing loss (AHL) in mice. In linkage backcrosses, the recessive Cdh23 allele (ahl) of the C57BL/6J strain, when homozygous, confers increased susceptibility to AHL, while the dominant allele (Ahl+) of the CBA/CaJ strain confers resistance. To determine the isolated effects of these alleles on different strain backgrounds, we produced the reciprocal congenic strains B6.CBACa-Cdh23(Ahl)(+) and CBACa.B6-Cdh23(ahl) and tested 15-30 mice from each for hearing loss progression. ABR thresholds for 8 kHz, 16 kHz, and 32 kHz pure-tone stimuli were measured at 3, 6, 9, 12, 15 and 18 months of age... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534603 Tue, 22 Nov 2011 05:00:00 +0100 5534603 http://www.medworm.com/index.php?rid=5534602&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22138630%26dopt%3DAbstract Authors: Zhu Z, Tang Q, Zeng FG, Guan T, Ye D Abstract Sharp spatial selectivity is critical to auditory performance, particularly in pitch-related tasks. Most contemporary cochlear implants have employed monopolar stimulation that produces broad electric fields, which presumably contribute to poor pitch and pitch-related performance by implant users. Bipolar or tripolar stimulation can generate focused electric fields but requires higher current to reach threshold and, more interestingly, has not produced any apparent improvement in cochlear-implant performance. The present study addressed this dilemma by measuring psychophysical and physiological spatial selectivity with both broad and focused stimulations in the same cohort of subjects. Different current levels were adjusted by ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534602 Tue, 22 Nov 2011 05:00:00 +0100 5534602 http://www.medworm.com/index.php?rid=5534604&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22127330%26dopt%3DAbstract Authors: Werner M, Van De Water TR, Andersson T, Arnoldsson G, Berggren D Abstract A method for long term culture of utricular macula explants is demonstrated to be stable and reproducible over a period of 28 days in vitro (DIV). This culture system for four-day-old rat utricular maculae is potentially suitable for studies of hair cell loss, repair and regeneration processes as they occur in post-natal mammalian inner ear sensory epithelia. The cellular events that occur within utricular macula hair cell epithelia during 28 days of culture are documented from serial sections. Vestibular hair cells (HCs) and supporting cells (SCs) were systematically counted using light microscopy (LM) and the assistance of morphometric computer software. Ultrastructural observations were made with... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534604 Sun, 20 Nov 2011 05:00:00 +0100 5534604 http://www.medworm.com/index.php?rid=5534605&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22115725%26dopt%3DAbstract In this study, a three-dimensional finite-element model of the passive human cochlea was created. Dynamic behavior of the basilar membrane caused by the vibration of the stapes footplate was analyzed considering a fluid-structure interaction with the cochlear fluid. Next, the effects of a perilymphatic fistula (PLF) on the vibration of the cochlea were examined by making a small hole on the wall of the cochlea model. Even if a PLF existed in the scala vestibuli, a traveling wave was generated on the basilar membrane. When a PLF existed at the basal end of the cochlea, the shape of the traveling wave envelope showed no remarkable change, but the maximum amplitude became smaller at the entire frequency range from 0.5 to 5kHz and decreased with decreasing frequency. In contrast, when a PLF ex... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5534605 Tue, 15 Nov 2011 05:00:00 +0100 5534605 http://www.medworm.com/index.php?rid=5439970&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22101024%26dopt%3DAbstract Authors: Papesh MA, Hurley LM Abstract Acoustic trauma often results in permanent damage to the cochlea, triggering changes in processing within central auditory structures such as the inferior colliculus (IC). The serotonergic neuromodulatory system, present in the IC, is responsive to chronic changes in the activity of sensory systems. The current study investigated whether the density of serotonergic innervation in the IC is changed following acoustic trauma. The trauma stimulus consisted of an 8 kHz pure tone presented at a level of 113 dB SPL for six consecutive hours to anesthetized CBA/J mice. Following a minimum recovery period of three weeks, serotonergic fibers were visualized via histochemical techniques targeting the serotonin reuptake transporter (SERT) and quantifie... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5439970 Fri, 11 Nov 2011 05:00:00 +0100 5439970 http://www.medworm.com/index.php?rid=5439973&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22101021%26dopt%3DAbstract Authors: Witt KM, Bockman CS, Dang HK, Gruber DD, Wangemann P, Scofield MA Abstract The spiral modiolar artery supplies blood and essential nutrients to the cochlea. Our previous functional study indicates the α(1A)-adrenergic receptor subtype mediates vasoconstriction of the gerbil spiral modiolar artery. Although the gerbil cochlea is often used as a model in hearing research, the molecular and pharmacological characteristics of the cloned gerbil α(1a)-adrenergic receptor have not been determined. Thus we cloned, expressed and characterized the gerbil α(1a)-adrenergic receptor and then compared its molecular and pharmacological properties to those of other mammalian α(1a)-adrenergic receptors. The cDNA clone contained 1404 nucleotides, which encoded a 467 amino acid peptide w... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5439973 Thu, 10 Nov 2011 05:00:00 +0100 5439973 http://www.medworm.com/index.php?rid=5439972&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22101022%26dopt%3DAbstract This study investigated whether introducing irrelevant content information into the prime reduces the priming effect. The results showed that presenting the first four syllables (not including the second and third keywords) of the three-keyword target sentence in quiet significantly improved recognition of the second and third keywords in a two-talker-speech masker but not a noise masker, relative to the no-priming condition. Increasing the prime content from four to eight syllables (including the first and second keywords of the target sentence) further improved recognition of the third keyword in either the noise or speech masker. However, if the last four syllables of the eight-syllable prime were replaced by four irrelevant syllables (which did not occur in the target sentence), all th... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5439972 Thu, 10 Nov 2011 05:00:00 +0100 5439972 http://www.medworm.com/index.php?rid=5439971&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22101023%26dopt%3DAbstract Authors: Alain C, McDonald K, Van Roon P Abstract Older adults presented with short (i.e., 40 ms) harmonic complex tones show a reduced likelihood of hearing the mistuned harmonic as a separate sound. Here, we examined whether this age difference for the mistuned harmonic would generalize to a longer signal duration (i.e., 200 ms). We measured auditory evoked fields (AEFs) using magnetoencephalography while young and older adults were presented with harmonic complex tones that either had all partials of the tones in tune (single sound object) or contained a 4 or 16% mistuned harmonic (dual sound objects). The auditory stimuli were presented in isolation or embedded in low or moderate levels of continuous white noise. For each participant, we modeled the AEFs with a pair of dipole... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5439971 Wed, 09 Nov 2011 05:00:00 +0100 5439971 http://www.medworm.com/index.php?rid=5439974&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22094003%26dopt%3DAbstract Authors: Haugas M, Lilleväli K, Salminen M Abstract The development of the inner ear sensory epithelia involves a complex network of transcription factors and signaling pathways and the whole process is not yet entirely understood. GATA3 is a DNA-binding factor that is necessary for otic morphogenesis and without GATA3 variable defects have been observed already at early stages in mouse embryos. In the less severe phenotypes, one small oval shaped vesicle is formed whereas in the more severe cases, the otic epithelium becomes disrupted and the endolymphatic domain becomes separated from the rest of the otic epithelium. Despite these defects, the early sensory fate specification occurs in Gata3-/- otic epithelium. However, due to the early lethality of Gata3-deficient embryos, the ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5439974 Mon, 07 Nov 2011 05:00:00 +0100 5439974 http://www.medworm.com/index.php?rid=5420117&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22085487%26dopt%3DAbstract In conclusion we showed that AOE triggers deafness at early stages and this is correlated with profound changes in the firing pattern and frequency of the DCN major output fusiform cells. The changes here described could represent the initial network imbalance prior to the emergence of tinnitus. PMID: 22085487 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5420117 Mon, 07 Nov 2011 05:00:00 +0100 5420117 http://www.medworm.com/index.php?rid=5420118&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22079774%26dopt%3DAbstract Authors: Owen Brimijoin W, McShefferty D, Akeroyd MA Abstract It has long been understood that the level of a sound at the ear is dependent on head orientation, but the way in which listeners move their heads during listening has remained largely unstudied. Given the task of understanding a speech signal in the presence of a simultaneous noise, listeners could potentially use head orientation to either maximize the level of the signal in their better ear, or to maximize the signal-to-noise ratio in their better ear. To establish what head orientation strategy listeners use in a speech comprehension task, we used an infrared motion-tracking system to measure the head movements of 36 listeners with large (>16 dB) differences in hearing threshold between their left and right ears.... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5420118 Sun, 06 Nov 2011 04:00:00 +0100 5420118 http://www.medworm.com/index.php?rid=5379676&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22051189%26dopt%3DAbstract Authors: Canlon B, Schacht J PMID: 22051189 [PubMed - in process] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5379676 Tue, 01 Nov 2011 04:00:00 +0100 5379676 http://www.medworm.com/index.php?rid=5379677&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22037489%26dopt%3DAbstract Authors: Chordekar S, Kriksunov L, Kishon-Rabin L, Adelman C, Sohmer H Abstract Auditory sensation can be elicited not only by air conducted (AC) sound or bone conducted (BC) sound, but also by stimulation of soft tissue (STC) sites on the head and neck relatively distant from deeply underlying bone. Tone stimulation by paired combinations of AC with BC (mastoid) and/or with soft tissue conduction produce the same pitch sensation, mutual masking and beats. The present study was designed to determine whether they can also cancel each other. The study was conducted on ten normal hearing subjects. Tones at 2 kHz were presented in paired combinations by AC (insert earphone), by BC (bone vibrator) at the mastoid, and by the same bone vibrator to several STC sites; e.g. the neck, the st... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5379677 Fri, 21 Oct 2011 04:00:00 +0100 5379677 http://www.medworm.com/index.php?rid=5344980&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22008826%26dopt%3DAbstract CONCLUSION: The variance in the between-ear difference across the temporal bones studied indicates that useful effect sizes can be reliably identified using subject numbers that are practical for temporal bone studies. For instance, there is 95% likelihood that an interaural difference in SGC count of approximately 1000 cells associated with a treatment/manipulation of one ear will be reliably detected in a bilaterally-symmetric profound hearing loss population of temporal bones from approximately 10 subjects. PMID: 22008826 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5344980 Thu, 13 Oct 2011 04:00:00 +0100 5344980 http://www.medworm.com/index.php?rid=5344981&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22000998%26dopt%3DAbstract Authors: Petacchi A, Kaernbach C, Ratnam R, Bower JM Abstract Recent years have seen a growing debate concerning the function of the cerebellum. Here we used a pitch discrimination task and PET to test for cerebellar involvement in the active control of sensory data acquisition. Specifically, we predicted greater cerebellar activity during active pitch discrimination compared to passive listening, with the greatest activity when pitch discrimination was most difficult. Ten healthy subjects were trained to discriminate deviant tones presented with a slightly higher pitch than a standard tone, using a Go/No Go paradigm. To ensure that discrimination performance was matched across subjects, individual psychometric curves were assessed beforehand using a two-step psychoacoustic procedu... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5344981 Sat, 08 Oct 2011 04:00:00 +0100 5344981 http://www.medworm.com/index.php?rid=5344979&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22016077%26dopt%3DAbstract Authors: Shearer AE, Hildebrand MS, Sloan CM, Smith RJ Abstract Our understanding of hereditary hearing loss has greatly improved since the discovery of the first human deafness gene. These discoveries have only accelerated due to the great strides in DNA sequencing technology since the completion of the human genome project. Here, we review the immense impact that these developments have had in both deafness research and clinical arenas. We review commonly used genomic technologies as well as the application of these technologies to the genetic diagnosis of hereditary hearing loss and to the discovery of novel deafness genes. PMID: 22016077 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5344979 Sat, 08 Oct 2011 04:00:00 +0100 5344979 http://www.medworm.com/index.php?rid=5344982&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21986211%26dopt%3DAbstract Authors: Etchelecou MC, Coulet O, Derkenne R, Tomasi M, Noreña AJ Abstract Hearing loss is routinely estimated from the audiogram, even though this measure gives only a rough approximation of hearing. Indeed, cochlear regions functioning poorly, if at all, called dead regions, are not detected by a simple audiogram. To detect cochlear dead regions, additional measurements of psychophysical tuning curves or thresholds in background noise (TEN test) are required. A first aim of this study was to assess the presence of dead regions after impulse noise trauma using psychophysical tuning curves. The procedure we used was based on a compromise between the need to collect reliable estimates of psychophysical tuning curves and the limited time available to obtain these estimates in a hosp... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5344982 Wed, 05 Oct 2011 04:00:00 +0100 5344982 http://www.medworm.com/index.php?rid=5344983&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21986210%26dopt%3DAbstract Authors: Beyer LA, Galano MM, Nair TS, Kommareddi PK, Sha SH, Raphael Y, Carey TE Abstract The membrane glycoprotein CTL2/SLC44A2 is expressed by supporting cells in the inner ear and has been identified as a target of antibodies that may induce auto-immune hearing loss. To determine if CTL2/SLC44A2 also has roles in inner ear development and to distinguish between isoform-specific roles, we assessed age-related changes in expression of CTL2/SLC44A2 isoforms and protein in the developing murine inner ear. We determined that both isoform p1 and isoform p2 (named for the upstream p1 and proximal p2 promoters that control alternate exons 1a and 1b) were robustly expressed as early as E14 and persisted during embryonic development, but after birth the p1 isoform fell to barely detectab... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5344983 Sat, 01 Oct 2011 04:00:00 +0100 5344983 http://www.medworm.com/index.php?rid=5344984&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21983133%26dopt%3DAbstract Authors: Chen Z, Hu G, Glasberg BR, Moore BC Abstract A model for calculating auditory excitation patterns and loudness for steady sounds for normal hearing is extended to deal with cochlear hearing loss. The filters used in the model have a double ROEX-shape, the gain of the narrow active filter being controlled by the output of the broad passive filter. It is assumed that the hearing loss at each audiometric frequency can be partitioned into a loss due to dysfunction of outer hair cells (OHCs) and a loss due to dysfunction of inner hair cells (IHCs). OHC loss is modeled by decreasing the maximum gain of the active filter, which results in increased absolute threshold, reduced compressive nonlinearity and reduced frequency selectivity. IHC loss is modeled by a level-dependent atte... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5344984 Thu, 29 Sep 2011 04:00:00 +0100 5344984 http://www.medworm.com/index.php?rid=5297060&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21979311%26dopt%3DAbstract This study demonstrated that metformin prevented gentamicin induced apoptosis through the calcium modulating and ROS reducing anti-apoptotic effects. PMID: 21979311 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5297060 Wed, 28 Sep 2011 04:00:00 +0100 5297060 http://www.medworm.com/index.php?rid=5280087&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21951489%26dopt%3DAbstract Mass distribution and rotational inertia of "microtype" and "freely mobile" middle ear ossicles in rodents. Hear Res. 2011 Sep 19; Authors: Lavender D, Taraskin SN, Mason MJ Abstract The middle ears of seven species of rodents, including four hamster species, were examined under light microscopy and through micro-CT imaging. Hamsters were found to possess a spectrum of ossicular morphologies ranging from something approaching "freely mobile" (Mesocricetus) to something nearer the "microtype" (Cricetulus), although no hamster has an orbicular apophysis of the malleus. Rats, mice and Calomyscus were found to have typically microtype ossicles. To explore the functional effects of these morphological differences, CT scan data were used to calculate the magnitudes of the moments... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5280087 Mon, 19 Sep 2011 04:00:00 +0100 5280087 http://www.medworm.com/index.php?rid=5280089&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21944944%26dopt%3DAbstract Authors: Brown DJ, Gibson WP Abstract We have cyclically suppressed the 2f1-f2 distortion product otoacoustic emission (DPOAE) with low-frequency tones (17-97 Hz) as a way of differentially diagnosing the endolymphatic hydrops assumed to be associated with Ménière's syndrome. Round-window electrocochleography (ECochG) was performed in subjects with sensorineural hearing loss (SNHL) on the day of DPOAE testing, and from which the amplitude of the summating potential (SP) was measured, to support the diagnosis of Ménière's syndrome based on symptoms. To summarize and compare the cyclic patterns of DPOAE modulation in these groups we have used the simplest model of DPOAE generation and modulation, by assuming that the DPOAEs were generated by a 1st-order Boltzmann nonlinearity so... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5280089 Fri, 16 Sep 2011 04:00:00 +0100 5280089 http://www.medworm.com/index.php?rid=5280088&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945200%26dopt%3DAbstract Authors: Warrier CM, Abrams DA, Nicol TG, Kraus N Abstract The human auditory brainstem is known to be exquisitely sensitive to fine-grained spectro-temporal differences between speech sound contrasts, and the ability of the brainstem to discriminate between these contrasts is important for speech perception. Recent work has described a novel method for translating brainstem timing differences in response to speech contrasts into frequency-specific phase differentials. Results from this method have shown that the human brainstem response is surprisingly sensitive to phase differences inherent to the stimuli across a wide extent of the spectrum. Here we use an animal model of the auditory brainstem to examine whether the stimulus-specific phase signatures measured in human brainstem... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5280088 Fri, 16 Sep 2011 04:00:00 +0100 5280088 http://www.medworm.com/index.php?rid=5246929&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21924333%26dopt%3DAbstract Authors: Campbell K, Claussen A, Meech R, Verhulst S, Fox D, Hughes L Abstract We have previously reported rescue from noise-induced auditory brainstem response (ABR) threshold shifts with d-methionine (d-met) administration 1 h after noise exposure. The present study investigated further d-met rescue intervals at 3, 5 and 7 h post-noise exposure. Chinchillas laniger were exposed to a 6 h 105 dB sound pressure level (dB SPL) octave band noise (OBN) and then administered d-met i.p. starting 3, 5, or 7 h after noise exposure; controls received saline i.p. immediately after noise exposure. ABR assessments were performed at baseline and on post-exposure days 1 and 21. Outer hair cell (OHC) loss was measured in cochleae obtained at sacrifice 21 days post-exposure. Administration of... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5246929 Tue, 06 Sep 2011 04:00:00 +0100 5246929 http://www.medworm.com/index.php?rid=5230399&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21920420%26dopt%3DAbstract Authors: Liu C, Jin SH Abstract The purpose of this study was to evaluate whether there were significant differences in audibility of American English vowels in noise produced by non-native speakers and native speakers. Detection thresholds for 12 English vowels with equalized durations of 170ms produced by 10 English-, Chinese- and Korean-native speakers were measured for young normal-hearing English-native listeners in the presence of speech-shaped noise presented at 70dB SPL. Similar patterns of vowel detection thresholds as a function of the vowel category were found for native and non-native speakers, with the highest thresholds for /u/ and /ʊ/ and lowest thresholds for /i/ and /e/. In addition, vowel detection thresholds for non-native speakers were significantly lower and s... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5230399 Mon, 05 Sep 2011 04:00:00 +0100 5230399 http://www.medworm.com/index.php?rid=5218972&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907782%26dopt%3DAbstract Authors: Tierney A, Parbery-Clark A, Skoe E, Kraus N Abstract The addition of background noise to an auditory signal delays brainstem response timing. This effect has been extensively documented using manual peak selection. Peak picking, however, is impractical for large-scale studies of spectrotemporally complex stimuli, and leaves open the question of whether noise-induced delays are frequency-dependent or occur across the frequency spectrum. Here we use an automated, objective method to examine phase shifts between auditory brainstem responses to a speech sound (/da/) presented with and without background noise. We predicted that shifts in neural response timing would also be reflected in frequency-specific phase shifts. Our results indicate that the addition of background noise... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5218972 Mon, 05 Sep 2011 04:00:00 +0100 5218972 http://www.medworm.com/index.php?rid=5218973&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907781%26dopt%3DAbstract Authors: Pillai JA, Siegel JH Abstract Tamoxifen has been used extensively in the treatment of breast cancer and other neoplasms. In addition to its well-known action on estrogen receptors it is also known to acutely block chloride channels that participate in cell volume regulation. Tamoxifen's role in preventing cochlear outer hair cell (OHC) swelling in vitro suggested that OHC swelling noted following noise exposure could potentially be a therapeutic target for Tamoxifen in its role as a chloride channel blocker to help prevent noise-induced hearing loss. To investigate this possibility, the effects of exposure to Tamoxifen on physiologic measures of cochlear function in the presence and absence of subsequent noise exposure were studied. Male Mongolian gerbils (2-4 months old)... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5218973 Fri, 02 Sep 2011 04:00:00 +0100 5218973 http://www.medworm.com/index.php?rid=5218974&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21906667%26dopt%3DAbstract Authors: Martini M, Canella R, Prigioni I, Russo G, Tavazzani E, Fesce R, Rossi ML Abstract The effects of acute gentamicin application on hair cells isolated from the frog semicircular canals have been tested by using the patch-clamp technique in the whole-cell configuration. Extracellular gentamicin (1 mM) mostly affected the Ca(2+) macrocurrent, I(Ca), and the Ca-dependent K(+) current, I(KCa). The drug, applied to the hair cell basolateral membrane through a fast perfusion system, produced a rapid and relevant decrease (∼34%) of I(Ca) amplitude, without apparently affecting its activation-deactivation kinetics. The I(KCa) component of the delayed I(KD) was similarly affected: peak and steady-state mean amplitudes were significantly reduced, by about 47 and 54%, respectively,... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5218974 Tue, 30 Aug 2011 04:00:00 +0100 5218974 http://www.medworm.com/index.php?rid=5218975&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21893181%26dopt%3DAbstract CONCLUSION: This study demonstrates the phenotypic heterogeneity in this large family with an X-linked pattern of inherited sensorineural hearing impairment. The men showed more severe hearing impairment at a younger age with more pronounced progression during the first two decades of life, while women demonstrated less severe hearing impairment with more gradual progression and a wider variation in age of onset, degree of hearing impairment and inter-aural asymmetry in thresholds. PMID: 21893181 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5218975 Sat, 27 Aug 2011 04:00:00 +0100 5218975 http://www.medworm.com/index.php?rid=5192930&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21878379%26dopt%3DAbstract Authors: Garinis A, Werner L, Abdala C Abstract Otoacoustic emission (OAE) amplitude can be reduced by acoustic stimulation. This effect is produced by the medial olivocochlear (MOC) reflex. Past studies have shown that the MOC reflex is related to listening in noise and attention. In the present study, the relationship between strength of the contralateral MOC reflex and masked threshold was investigated in 19adults. Detection thresholds were determined for a 1000-Hz, 300-ms tone presented simultaneously with one repetition of a 300-ms masker in an ongoing train of 300-ms masker bursts at 600-ms intervals. Three masking conditions were tested: 1) broadband noise 2) a fixed-frequency 4-tone complex masker and 3) a random-frequency 4-tone complex masker. Broadband noise was expected... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5192930 Fri, 26 Aug 2011 23:00:00 +0100 5192930 http://www.medworm.com/index.php?rid=5175858&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21872651%26dopt%3DAbstract Authors: Sun W, Manohar S, Jayaram A, Kumaraguru A, Fu Q, Li J, Allman B Abstract Recent clinical reports found a high incidence of recurrent otitis media in children suffering hyperacusis, a marked intolerance to an otherwise ordinary environmental sound. However, it is unclear whether the conductive hearing loss caused by otitis media in early age will affect sound tolerance later in life. Thus, we have tested the effects of tympanic membrane (TM) damage at an early age on sound perception development in rats. Two weeks after the TM perforation, more than 80% of the rats showed audiogenic seizure (AGS) when exposed to loud sound (120 dB SPL white noise, < 1 min). The susceptibility of AGS lasted at least sixteen weeks after the TM damage, even the hearing loss recovered. Th... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5175858 Wed, 24 Aug 2011 23:00:00 +0100 5175858 http://www.medworm.com/index.php?rid=5157318&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21854840%26dopt%3DAbstract Authors: Ding D, He J, Allman BL, Yu D, Jiang H, Seigel GM, Salvi RJ Abstract Ototoxicity is a dose-limiting side effect of chemotherapeutic treatment with cisplatin. In a series of experiments on neonatal rat cochlear organotypic cultures, the extent of damage induced by a broad range of cisplatin treatment concentrations was examined. Paradoxically, it was found that hair cell loss was greater following 48 h exposure to low (10, 50 and 100 μM) versus high (400 and 1000 μM) concentrations of cisplatin; these findings indicate that hair cells possess intrinsic resistance to high levels of extracellular cisplatin. Using cisplatin conjugated to Alexa Fluor 488, it was found that cisplatin is readily taken up by hair cells at low concentrations, but is largely excluded at high co... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5157318 Thu, 11 Aug 2011 23:00:00 +0100 5157318 http://www.medworm.com/index.php?rid=5157319&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21851853%26dopt%3DAbstract Authors: Chen Z, Hu G, Glasberg BR, Moore BC Abstract A new method for calculating auditory excitation patterns and loudness for steady sounds is described. The method is based on a nonlinear filterbank in which each filter is the sum of a broad passive filter and a sharp active filter. All filters have a rounded-exponential shape. For each center frequency (CF), the gain of the active filter is controlled by the output of the passive filter. The parameters of the model were derived from large sets of previously published notched-noise masking data obtained from human subjects. Excitation patterns derived using the new filterbank include the effects of basilar membrane compression. Loudness can be calculated as the area under the excitation pattern when plotted in intensity-like un... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5157319 Tue, 09 Aug 2011 23:00:00 +0100 5157319 http://www.medworm.com/index.php?rid=5141350&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839158%26dopt%3DAbstract Authors: Altmann CF, Klein C, Heinemann LV, Wibral M, Gaese BH, Kaiser J Abstract Frequency modulations (FM) play a decisive role in our everyday communication. To investigate the processing of FM direction we measured change-related auditory cortex responses with human magnetoencephalography. First, we tested for FM direction selectivity by presenting FM sweeps with the same FM directions in a repeated series (RS). These series were interrupted by a deviant with the opposite FM direction. Second, we tested for the representation of abstract rules and presented series of FM sweeps with alternating FM directions (AS). The AS series were interrupted by a deviant which was a repetition of the series' last FM sweep but broke the alternating pattern. For the RS, the deviant did not evok... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5141350 Thu, 04 Aug 2011 23:00:00 +0100 5141350 http://www.medworm.com/index.php?rid=5141351&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21820501%26dopt%3DAbstract Authors: Deroche ML, Culling JF Abstract Three experiments investigated listeners' ability to detect a narrow band of noise, centered on one partial of a random-phase complex tone, as a function of inharmonicity. Inharmonicity was generated by randomly mistuning the partial frequencies from a 100-Hz fundamental frequency (F0). In experiment 1, masked detection thresholds were lower when the masker was harmonic than when it was inharmonic for target bands in the range 0.5-2.5 kHz. The presence of this masking level difference due to harmonicity (HMLD) in regions of resolved partials and the reduction of the HMLD with increasing center frequency did not support the idea that HMLD was primarily caused by the envelope modulations produced by the beating of unresolved partials within a... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5141351 Wed, 27 Jul 2011 23:00:00 +0100 5141351 http://www.medworm.com/index.php?rid=5102694&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21801824%26dopt%3DAbstract This study examines the test-retest reliability of distortion-product otoacoustic emissions (DPOAEs) in ketamine-anesthetized common marmosets (Callithrix jacchus). DPOAE gain functions were measured at 16 f(2)-frequencies between 3 and 24 kHz. Test-retest reliability was assessed at the following time intervals: (1) Interleaved, in which two gain functions were obtained at each frequency before advancing to the next frequency, (2) Immediate, wherein one gain function was collected at all f(2)-frequencies and the retest was immediately performed without removing the probe tip, (3) Short-term, in which the retest followed a 10-min period with the probe removed, and (4) Long-term, wherein the retest was performed at least one week after the initial test. Reliability was assessed using four ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5102694 Tue, 26 Jul 2011 23:00:00 +0100 5102694 http://www.medworm.com/index.php?rid=5102696&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21801823%26dopt%3DAbstract A model-based analysis of the "combined-stimulation advantage" Hear Res. 2011 Jul 26; Authors: Seldran F, Micheyl C, Truy E, Berger-Vachon C, Thai-Van H, Gallego S Improvements in speech-recognition performance resulting from the addition of low-frequency information to electric (or vocoded) signals have attracted considerable interest in recent years. An important question is whether these improvements reflect a form of constructive perceptual interaction-whereby acoustic cues enhance the perception of electric or vocoded signals-or whether they can be explained without assuming any interaction. To address this question, speech-recognition performance was measured in 24 normal-hearing listeners using lowpass-filtered, vocoded, and "combined" (lowpass + vocoded) words present... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5102696 Mon, 25 Jul 2011 23:00:00 +0100 5102696 http://www.medworm.com/index.php?rid=5102688&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21810457%26dopt%3DAbstract Authors: Weegerink NJ, Schraders M, Leijendeckers J, Slieker K, Huygen PL, Hoefsloot L, Oostrik J, Pennings RJ, Simon A, Snik A, Kremer H, Kunst HP Description of the audiometric and vestibular characteristics of a Dutch family with Muckle-Wells syndrome (MWS). Examination of all family members consisted of pure tone audiometry, otoscopy and genetic analysis. In addition, a selected group underwent speech audiometry, vestibulo-ocular examination, acoustic reflex testing and tests assessing loudness scaling, gap detection, difference limen for frequency and speech perception in noise. Linear regression analyses were performed on the audiometric data. Six clinically affected family members participated in this study and all were carriers of a p.Tyr859His mutation in the NLPR3 gene. Most ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5102688 Fri, 22 Jul 2011 23:00:00 +0100 5102688 http://www.medworm.com/index.php?rid=5102687&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21810458%26dopt%3DAbstract CONCLUSION: LMWF enhances the regeneration of hair cells damaged by neomycin. The mechanism may involve the Notch signaling pathway. LMWF shows promise as a therapeutic agent for hearing and balance disorders. PMID: 21810458 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5102687 Fri, 22 Jul 2011 23:00:00 +0100 5102687 http://www.medworm.com/index.php?rid=5102697&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21798325%26dopt%3DAbstract Authors: Schraven SP, Hirt B, Gummer AW, Zenner HP, Dalhoff E Stimulation of the round window (RW) has gained increasing clinical importance. Clinical, as well as human temporal bone and in-vivo animal studies show considerable variability. The influence of RW stimulation on the cochlea remains unclear. We designed a human temporal-bone study with controlled direct mechanical stimulation of the RW membrane to identify conditions for successful RW stimulation. Eight human temporal bones were stimulated on the RW by piezoelectric stack actuators with cylindrical aluminium rods of diameter 0.5 mm and with either flat or 30° inclined top surface. Using a dedicated two-stage positioning protocol for the actuator, we achieved highly reproducible measurements of the stimulus vibration at t... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5102697 Tue, 19 Jul 2011 23:00:00 +0100 5102697 http://www.medworm.com/index.php?rid=5102699&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21782914%26dopt%3DAbstract Authors: Op de Beeck K, Schacht J, Van Camp G Apoptosis is an important physiological process. Normally, a healthy cell maintains a delicate balance between pro- and anti-apoptotic factors, allowing it to live and proliferate. It is thus not surprising that disturbance of this delicate balance may result in disease. It is a well known fact that apoptosis also contributes to several acquired forms of hearing impairment. Noise-induced hearing loss is the result of prolonged exposure to excessive noise, triggering apoptosis in terminally differentiated sensory hair cells. Moreover, hearing loss caused by the use of therapeutic drugs such as aminoglycoside antibiotics and cisplatin potentially may result in the activation of apoptosis in sensory hair cells leading to hearing loss due to th... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5102699 Sun, 17 Jul 2011 23:00:00 +0100 5102699 http://www.medworm.com/index.php?rid=5102698&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21782915%26dopt%3DAbstract We present a method for obtaining a complete geometry model of the fluid chambers of cochlea (scalae) from tomography images. An accurate segmentation of cochlea is problematic due to the low contrast of the inner membranes of scalae. Our method of 3D segmentation is based on dynamic resampling of an original image stack to achieve a perpendicular cross-section of the scalae on all sections. Subsequently, perpendicular cross-section is being segmented using 2D active contours. The center of mass of the contour is extracted and used to predict further course of scalae centerline by Kalman filter. Cross-section contours are subsequently assembled to the total geometry model. This method has been applied to CT images, but we expect that it could be used for segmentation of strongly curved low... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5102698 Sun, 17 Jul 2011 23:00:00 +0100 5102698 http://www.medworm.com/index.php?rid=5054498&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21771649%26dopt%3DAbstract Authors: Zäske R, Schweinberger SR High-level adaptation not only biases the perception of faces, but also causes transient distortions in auditory perception of non-linguistic voice information about gender, identity, and emotional intonation. Here we report a novel auditory aftereffect in perceiving vocal age: age estimates were elevated in age-morphed test voices when preceded by adaptor voices of young speakers (∼20 yrs), compared to old adaptor voices (∼70 yrs). This vocal age aftereffect (VAAE) complements a recently reported face aftereffect (Schweinberger et al., 2010) and points to selective neuronal coding of vocal age. Intriguingly, post-adaptation assessment revealed that VAAEs could persist for minutes after adaptation, although reduced in magnitude. As an important ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5054498 Tue, 12 Jul 2011 23:00:00 +0100 5054498 http://www.medworm.com/index.php?rid=5054500&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21762764%26dopt%3DAbstract Authors: Landry TG, Wise AK, Fallon JB, Shepherd RK Cochlear implants electrically stimulate residual spiral ganglion neurons (SGNs) to provide auditory cues for the severe-profoundly deaf. However, SGNs gradually degenerate following cochlear hair cell loss, leaving fewer neurons available for stimulation. Providing an exogenous supply of neurotrophins (NTs) has been shown to prevent SGN degeneration, and when combined with chronic intracochlear electrical stimulation (ES) following a short period of deafness (5 days), may also promote the formation of new neurons. The present study assessed the histopathological response of guinea pig cochleae treated with NTs (brain-derived neurotrophic factor and neurotrophin-3) with and without ES over a four week period, initiated two weeks after... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5054500 Tue, 05 Jul 2011 23:00:00 +0100 5054500 http://www.medworm.com/index.php?rid=5054499&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21763410%26dopt%3DAbstract Authors: Moreno LE, Rajguru SM, Matic AI, Yerram N, Robinson AM, Hwang M, Stock S, Richter CP It has been demonstrated that INS can be utilized to stimulate spiral ganglion cells in the cochlea. Although neural stimulation can be achieved without direct contact of the radiation source and the tissue, the presence of fluids or bone between the target structure and the radiation source may lead to absorption or scattering of the radiation, which may limit the efficacy of INS. The present study demonstrates the neural structures in the radiation beam path that can be stimulated. Histological reconstructions and microCT of guinea pig cochleae stimulated with an infrared laser suggest that the orientation of the beam from the optical fiber determined the site of stimulation in the cochlea. ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5054499 Sat, 02 Jul 2011 23:00:00 +0100 5054499 http://www.medworm.com/index.php?rid=5008574&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21723932%26dopt%3DAbstract Authors: Whitlon DS PMID: 21723932 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=5008574 Wed, 29 Jun 2011 23:00:00 +0100 5008574 http://www.medworm.com/index.php?rid=5008580&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21718769%26dopt%3DAbstract Authors: Meltser I, Canlon B Glucocorticoids are hormones released following stress-related events and function to maintain homeostasis. Glucocorticoid receptors localize, among others, to hair cells, spiral ligament and spiral ganglion neurons. Glucocorticoid receptor-induced protection against acoustic trauma is found by i) pretreatment with glucocorticoid agonists; ii) acute restraint stress; and iii) sound conditioning. In contrast, glucocorticoid receptor antagonists exacerbate hearing loss. These findings have important clinical significance since synthetic glucocorticoids are commonly used to treat hearing loss. However, this treatment has limited success since hearing improvement is often not maintained once the treatment has ended, a fact that reduces the overall appeal for t... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5008580 Mon, 20 Jun 2011 23:00:00 +0100 5008580 http://www.medworm.com/index.php?rid=5008581&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21699970%26dopt%3DAbstract Authors: Henry KS, Kale S, Scheidt RE, Heinz MG Noninvasive auditory brainstem responses (ABRs) are commonly used to assess cochlear pathology in both clinical and research environments. In the current study, we evaluated the relationship between ABR characteristics and more direct measures of cochlear function. We recorded ABRs and auditory nerve (AN) single-unit responses in seven chinchillas with noise-induced hearing loss. ABRs were recorded for 1-8 kHz tone burst stimuli both before and several weeks after 4 h of exposure to a 115 dB SPL, 50 Hz band of noise with a center frequency of 2 kHz. Shifts in ABR characteristics (threshold, wave I amplitude, and wave I latency) following hearing loss were compared to AN-fiber tuning curve properties (threshold and frequency selectivi... Hearing Research journals http://www.medworm.com/rss/comments.php?id=5008581 Tue, 14 Jun 2011 23:00:00 +0100 5008581 http://www.medworm.com/index.php?rid=4912305&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21640176%26dopt%3DAbstract In this study, we presented broadband noise bursts at 24 equally spaced locations in a 360° horizontal plane in both normal-hearing conditions and when listeners were fitted with a unilateral earplug. Localization improvement was found over the initial four training sessions, prior to plug insertion which produced an immediate and profound impairment in localization, particularly on the side of the plug. Subsequent training with the plug in place over the next 5 days showed continually improving performance (learning) up to the 4th day. Following plug removal, localization immediately returned to pre-plug levels. These results showed that task-specific training can improve localization ability in normal-hearing conditions and that training also improves performance during a unilateral con... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912305 Thu, 26 May 2011 23:00:00 +0100 4912305 http://www.medworm.com/index.php?rid=4912304&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21640177%26dopt%3DAbstract Authors: Klug A Reduced systems such as brain slices offer a powerful approach to study the physiology of auditory neurons in great detail. However, when studying auditory nuclei in reduced systems such as brain slices, especially highly active auditory brain stem nuclei, one has to be aware that the unphysiological lack of activity in the reduced system compared to the in-vivo situation has a number of important effects on the neurons under investigation, and thus on the data that are measured. Most importantly, the lack of chronic activity in the slice preparation has important effects on the properties of short-term plasticity of the synapses. The main purpose of this article is to discuss how spontaneous activity in auditory neurons, or the lack thereof, can affect the data measure... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912304 Thu, 26 May 2011 23:00:00 +0100 4912304 http://www.medworm.com/index.php?rid=4912303&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21640178%26dopt%3DAbstract Authors: Xie J, Talaska AE, Schacht J After almost seven decades in clinical use, aminoglycoside antibiotics still remain indispensible drugs for acute infections and specific indications such as tuberculosis or the containment of pseudomonas bacteria in patients with cystic fibrosis. The review will describe the pathology and pathophysiology of aminoglycoside-induced auditory and vestibular toxicity in humans and experimental animals and explore contemporary views of the mechanisms of cell death. It will also outline the current state of protective therapy and recent advances in the development of aminoglycoside derivatives with low toxicity profiles for antimicrobial treatment and for stop-codon suppression in the attenuation of genetic disorders. PMID: 21640178 [PubMed - as supp... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912303 Thu, 26 May 2011 23:00:00 +0100 4912303 http://www.medworm.com/index.php?rid=4912301&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21645602%26dopt%3DAbstract Authors: Ohlemiller KK, Rybak Rice ME, Rosen AD, Montgomery SC, Gagnon PM We recently demonstrated that sub-chronic low-dose kanamycin (KM, 300 mg/kg sc, 2×/day, 10 days) dramatically reduces permanent noise-induced hearing loss (NIHL) and hair cell loss in 1 month old CBA/J mice (Fernandez et al., 2010, J. Assoc. Res. Otolaryngol. 11, 235-244). Protection by KM remained for at least 48 h after the last dose, and appeared to involve a cumulative effect of multiple doses as part of a preconditioning process. The first month of life lies within the early 'sensitive period' for both cochlear noise and ototoxic injury in mice, and CBA/J mice appear exquisitely vulnerable to noise during this period (Ohlemiller et al., 2011; Hearing Res. 272, 13-20). From our initial data, we could not... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912301 Thu, 26 May 2011 23:00:00 +0100 4912301 http://www.medworm.com/index.php?rid=4912302&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21640179%26dopt%3DAbstract Authors: Lei D, Gao X, Perez P, Ohlemiller KK, Chen CC, Campbell KP, Hood AY, Bao J Loss of spiral ganglion neurons is a major cause of age-related hearing loss (presbycusis). Despite being the third most prevalent condition afflicting elderly persons, there are no known medications to prevent presbycusis. Because calcium signaling has long been implicated in age-related neuronal death, we investigated T-type calcium channels. This family is comprised of three members (Ca(v)3.1, Ca(v)3.2, and Ca(v)3.3), based on their respective main pore-forming alpha subunits: α1G, α1H, and α1I. In the present study, we report a significant delay of age-related loss of cochlear function and preservation of spiral ganglion neurons in α1H null and heterozygous mice, clearly demonstrating an importa... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912302 Wed, 25 May 2011 23:00:00 +0100 4912302 http://www.medworm.com/index.php?rid=4912306&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21624450%26dopt%3DAbstract Authors: Dalhoff E, Turcanu D, Gummer AW Recently it was shown that distortion product otoacoustic emissions (DPOAEs) can be measured as vibration of the human tympanic membrane in vivo, and proposed to use these vibration DPOAEs to support a differential diagnosis of middle-ear and cochlear pathologies. Here, we investigate how the reverse transfer function (r-TF), defined as the ratio of DPOAE-velocity of the umbo to DPOAE-pressure in the ear canal, can be used to diagnose the state of the middle ear. Anaesthetized guinea pigs served as the experimental animal. Sound was delivered free-field and the vibration of the umbo measured with a laser Doppler vibrometer (LDV). Sound pressure was measured 2-3 mm from the tympanic membrane with a probe-tube microphone. The forward transfer fu... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912306 Sun, 22 May 2011 23:00:00 +0100 4912306 http://www.medworm.com/index.php?rid=4912310&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21616131%26dopt%3DAbstract Authors: Clarke JC, Tuft BW, Clinger JD, Levine R, Figueroa LS, Allan Guymon C, Hansen MR Significant advances in the functional outcomes achieved with cochlear implantation will likely require tissue-engineering approaches to improve the neural prosthesis interface. One strategy is to direct spiral ganglion neuron (SGN) axon growth in a highly organized fashion to approximate or contact stimulating electrodes. Here we assessed the ability of micropatterns induced by photopolymerization in methacrylate (MA) polymer systems to direct cultured neonatal rat SGN neurite growth and alignment of SG Schwann cells (SGSCs). SGN survival and neurite length were comparable among various polymer compositions. Remarkably, there was no significant difference in SGN survival or neurite length between... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912310 Tue, 17 May 2011 23:00:00 +0100 4912310 http://www.medworm.com/index.php?rid=4912309&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21616132%26dopt%3DAbstract Authors: Campo P, Venet T, Rumeau C, Thomas A, Rieger B, Cour C, Cosnier F, Parietti-Winkler C Presbycusis, or age-related hearing loss is a growing problem as the general population ages. In this longitudinal study, the influence of noise or styrene exposure on presbycusis was investigated in Brown Norway rats. Animals were exposed at 6 months of age, either to a band noise centered at 8 kHz at a Lex,8h = 85 dB (86.2 dB SPL for 6 h), or to 300 ppm of styrene for 6 h per day, five days per week, for four weeks. Cubic distortion product otoacoustic emissions (2f1-f2 DPOAEs) were used to test the capacity of the auditory receptor over the lifespan of the animals. 2f1-f2DPOAE measurements are easy to implement and efficiently track the age-related deterioration of mid- and high-fr... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912309 Tue, 17 May 2011 23:00:00 +0100 4912309 http://www.medworm.com/index.php?rid=4912308&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21620939%26dopt%3DAbstract Authors: Kim SH, Marcus DC Na(+) concentrations in endolymph must be controlled to maintain hair cell function since the transduction channels of hair cells are cation-permeable, but not K(+)-selective. Flooding or fluctuations of the hair cell cytosol with Na(+) would be expected to lead to cellular dysfunction, hearing loss and vertigo. This review briefly describes cellular mechanisms known to be responsible for Na(+) homeostasis in each compartment of the inner ear, including the cochlea, saccule, semicircular canals and endolymphatic sac. The influx of Na(+) into endolymph of each of the organs is likely via passive diffusion, but these pathways have not yet been identified or characterized. Na(+) absorption is controlled by gate-keeper channels in the apical (endolymphatic) membr... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912308 Tue, 17 May 2011 23:00:00 +0100 4912308 http://www.medworm.com/index.php?rid=4912307&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21620940%26dopt%3DAbstract Authors: Shore SE This chapter reviews evidence for functional connections of the somatosensory and auditory systems at the very lowest levels of the nervous system. Neural inputs from the dosal root and trigeminal ganglia, as well as their brain stem nuclei, cuneate, gracillis and trigeminal, terminate in the cochlear nuclei. Terminations are primarily in the shell regions surrounding the cochlear nuclei but some terminals are found in the magnocellular regions of cochlear nucleus. The effects of stimulating these inputs on multisensory integration are shown as short and long-term, both suppressive and enhancing. Evidence that these projections are glutamatergic and are altered after cochlear damage is provided in the light of probable influences on the modulation and generation of ti... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4912307 Tue, 17 May 2011 23:00:00 +0100 4912307 http://www.medworm.com/index.php?rid=4863309&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21605648%26dopt%3DAbstract Authors: Pfingst BE, Bowling SA, Colesa DJ, Garadat SN, Raphael Y, Shibata SB, Strahl SB, Su GL, Zhou N Although the cochlear implant is already the world's most successful neural prosthesis, opportunities for further improvement abound. Promising areas of current research include work on improving the biological infrastructure in the implanted cochlea to optimize reception of cochlear implant stimulation and on designing the pattern of electrical stimulation to take maximal advantage of conditions in the implanted cochlea. In this review we summarize what is currently known about conditions in the cochlea of deaf, implanted humans and then review recent work from our animal laboratory investigating the effects of preserving or reinnervating tissues on psychophysical and electrophysiol... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863309 Fri, 13 May 2011 23:00:00 +0100 4863309 http://www.medworm.com/index.php?rid=4863313&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21586317%26dopt%3DAbstract Authors: Wang Y, O'Donohue H, Manis P The dynamics of synaptic transmission between neurons plays a major role in neural information processing. In the cochlear nucleus, auditory nerve synapses have a relatively high release probability and show pronounced synaptic depression that, in conjunction with the variability of interspike intervals, shapes the information transmitted to the postsynaptic cells. Cellular mechanisms have been best analyzed at the endbulb synapses, revealing that the recent history of presynaptic activity plays a complex, non-linear, role in regulating release. Emerging evidence suggests that the dynamics of synaptic function differs according to the target neuron within the cochlear nucleus. One consequence of hearing loss is changes in evoked release at survivin... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863313 Mon, 09 May 2011 23:00:00 +0100 4863313 http://www.medworm.com/index.php?rid=4863312&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21586318%26dopt%3DAbstract Authors: Reyes AD The auditory system must be able to adapt to changing acoustic environment and still maintain accurate representation of signals. Mechanistically, this is a difficult task because the responsiveness of a large heterogeneous population of interconnected neurons must be adjusted properly and precisely. Synaptic short-term plasticity (STP) is widely regarded as a viable mechanism for adaptive processes. Although the cellular mechanism for STP is well characterized, the overall effect on information processing at the network level is poorly understood. The main challenge is that there are many cell types in auditory cortex, each of which exhibit different forms and degrees of STP. In this article, I will review the basic properties of STP in auditory cortical circuits and... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863312 Mon, 09 May 2011 23:00:00 +0100 4863312 http://www.medworm.com/index.php?rid=4863311&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21596129%26dopt%3DAbstract Authors: Shibata SB, Budenz CL, Bowling SA, Pfingst BE, Raphael Y Following the onset of sensorineural hearing loss, degeneration of mechanosensitive hair cells and spiral ganglion cells (SGCs) in humans and animals occurs to variable degrees, with a trend for greater neural degeneration with greater duration of deafness. Emergence of the cochlear implant prosthesis has provided much needed aid to many hearing impaired patients and has become a well-recognized therapy worldwide. However, ongoing peripheral nerve fiber regression and subsequent degeneration of SGC bodies can reduce the neural targets of cochlear implant stimulation and diminish its function. There is increasing interest in bio-engineering approaches that aim to enhance cochlear implant efficacy by preventing SGC body de... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863311 Mon, 09 May 2011 23:00:00 +0100 4863311 http://www.medworm.com/index.php?rid=4863315&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21569828%26dopt%3DAbstract This study investigated the effects of long-term unilateral and bilateral amplification on central auditory processing in elderly people with symmetrical hearing loss using late auditory evoked potentials. It was hypothesized that in the unilateral setting stimulation of the aided ear would yield an acclimatization effect with larger amplitudes and shorter latencies of the components P1, N1 and P2 compared to those of the unaided ear. Auditory evoked potentials were elicited by 500, 1000 and 2000 Hz pure tones at 55, 70 and 85 dB SPL presentation level delivered either to the left or right ear. Unilaterally and bilaterally fitted experienced hearing-aid users and a control group of normally hearing adults, all aged at least 60 years, participated. The responses of the unilateral hearing-... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863315 Wed, 04 May 2011 23:00:00 +0100 4863315 http://www.medworm.com/index.php?rid=4863317&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21565263%26dopt%3DAbstract Authors: Wotton JM, Ferragamo MJ Anuran auditory nerve fibers (ANF) tuned to low frequencies display unusual frequency-dependent adaptation which results in a more phasic response to signals above best frequency (BF) and a more tonic response to signals below. A network model of the first two layers of the anuran auditory system was used to test the contribution of this dynamic peripheral adaptation on two-tone suppression and amplitude modulation (AM) tuning. The model included a peripheral sandwich component, leaky-integrate-and-fire cells and adaptation was implemented by means of a non-linear increase in threshold weighted by the signal frequency. The results of simulations showed that frequency-dependent adaptation was both necessary and sufficient to produce high-frequency-side t... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863317 Tue, 03 May 2011 23:00:00 +0100 4863317 http://www.medworm.com/index.php?rid=4863316&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21569827%26dopt%3DAbstract In conclusion, BC stimulation can activate the cochlea without two mobile windows. Furthermore, the cochlea can be activated by a fluid pathway and by application of a bone vibrator to non-osseous sites (soft tissue conduction). PMID: 21569827 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863316 Tue, 03 May 2011 23:00:00 +0100 4863316 http://www.medworm.com/index.php?rid=4863314&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21569829%26dopt%3DAbstract In this study, we used repetitive click trains to describe the spatial distribution of RRTF responses in cat anterior auditory field (AAF) and to discern potential variations in local temporal processing capacity. A majority of RRTF filters are band-pass. Temporal parameters estimated from RRTFs and corrected for characteristic frequency or latency dependencies are non-homogeneously distributed across AAF. Unlike the shallow global gradient observed in spectral receptive field parameters, transitions from loci with high to low temporal parameters are steep. Quantitative spatial analysis suggests non-uniform, circumscribed local organization for temporal pattern processing superimposed on global organization for spectral processing in cat AAF. PMID: 21569829 [PubMed - as supplied by pub... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863314 Tue, 03 May 2011 23:00:00 +0100 4863314 http://www.medworm.com/index.php?rid=4863318&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21557994%26dopt%3DAbstract This study examined the effects of deafness duration on the efficacy of NT gene therapy in preventing SGN loss in guinea pigs that were systemically deafened with aminoglycosides. Adenoviral vectors containing green fluorescent protein (GFP) with or without genes for Brain Derived Neurotrophic Factor (BDNF) and Neurotrophin-3 (NT3) were injected into the scala media (SM) compartment of cochleae that had been deafened for one, four or eight weeks prior to the viral injection. The results showed that viral transfection of cells within the SM was still possible even after severe degeneration of the OC. Supporting cells (pillar and Deiters' cells), cells within the stria vascularis, the spiral ligament, endosteal cells lining the scala compartments and interdental cells in the spiral limbus we... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863318 Sat, 30 Apr 2011 23:00:00 +0100 4863318 http://www.medworm.com/index.php?rid=4863310&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21600274%26dopt%3DAbstract Authors: Kelley MW, Mann ZF PMID: 21600274 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=4863310 Sat, 30 Apr 2011 23:00:00 +0100 4863310 http://www.medworm.com/index.php?rid=4808077&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21554941%26dopt%3DAbstract Authors: Wang X, Hu Y, Wang Z, Shi H Finite element (FE) model is used to analyze the coupling effects between ossicular chain and transducer of implantable middle-ear hearing devices. The mass loading of the transducer is attached to the long process of the incus in the form of floating mass transducer (FMT) or applied near the incus-stapes joint by a magnet of contactless electromagnetic transducer (CLT). By changing placement of the transducer, crimping connection and damping parameter of the crimping mechanism, theoretical performances of the transducers were investigated on mechanical characteristics in two aspects: (1) displacement change at the stapes footplate, which describes the change in hearing due to placement of the transducer; (2) the equivalent pressure output of the tr... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808077 Sat, 30 Apr 2011 23:00:00 +0100 4808077 http://www.medworm.com/index.php?rid=4808076&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21554942%26dopt%3DAbstract Authors: Atkinson PJ, Cho CH, Hansen MR, Green SH Jun N-terminal kinase (JNK) is a multifunctional protein kinase crucial for neuronal apoptosis as well as neurite growth. We have previously shown that JNK activity is correlated with spiral ganglion neuron (SGN) apoptosis following hair cell loss in rats (Alam et al., 2007) implying that JNK inhibition may have therapeutic potential to protect SGNs in deaf individuals. Here we investigated the role of JNK in neurite outgrowth from cultured neonatal rat and mouse SGNs. We show that JNK is required for initial growth of neurites and for continued extension of already established neurites. The effect of JNK inhibition on neurite growth is rapid and is also rapidly reversible after washout of the inhibitor. Using phosphoJNK immunoreactivi... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808076 Sat, 30 Apr 2011 23:00:00 +0100 4808076 http://www.medworm.com/index.php?rid=4808079&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21536120%26dopt%3DAbstract Authors: Patuzzi R This paper discusses how ion transport proteins in the hair cells of the mammalian cochlea work to produce a sensitive but stable hearing organ. The transport proteins in the inner and outer hair cells are summarized (including their current voltage characteristics), and the roles of these proteins in determining intracellular Ca(2+), membrane potential, and ultimately cochlear sensitivity are discussed. The paper also discusses the role of the Ca(2+) sequestration sacs in outer hair cells in the autoregulation of hair cell membrane potential and cochlear gain, and how the underdamped control of Ca(2+) within these sacs may produce the observed slow oscillations in cochlear sensitivity and otoacoustic emissions after cochlear perturbations, including perilymphatic pe... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808079 Fri, 22 Apr 2011 23:00:00 +0100 4808079 http://www.medworm.com/index.php?rid=4808083&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21527326%26dopt%3DAbstract Authors: Manley GA, Jones TA PMID: 21527326 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808083 Thu, 21 Apr 2011 23:00:00 +0100 4808083 http://www.medworm.com/index.php?rid=4808082&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21530627%26dopt%3DAbstract We report the inner ear tropism and potential ototoxicity of three previously untested vectors: early-generation adenovirus (Ad5.CMV.GFP), advanced-generation adenovirus (Adf.11D) and bovine adeno-associated virus (BAAV.CMV.GFP). Adenovirus showed robust tropism for organ of Corti supporting cells throughout the cochlea but induced increased ABR thresholds indicating ototoxicity. BAAV also showed tropism for organ of Corti supporting cells, with preferential transduction toward the cochlear apex. Additionally, BAAV readily transduced spiral ganglion neurons. Importantly, the BAAV-injected ears exhibited normal hearing at 5 weeks of age when compared to non-injected ears. Our results support the use of BAAV for safe and efficient targeting of supporting cell progenitors in the developing mu... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808082 Thu, 21 Apr 2011 23:00:00 +0100 4808082 http://www.medworm.com/index.php?rid=4808081&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21530628%26dopt%3DAbstract Authors: Fantetti KN, Zou Y, Fekete DM The peripheral growth cones of statoacoustic ganglion (SAG) neurons are presumed to sense molecular cues to navigate to their sensory targets during development. Based on previously reported expression data for Frizzled receptors, Wnt ligands, and Wnt inhibitors, we hypothesized that some members of the Wnt morphogen family may function as repulsive cues for SAG neurites. The responses of SAG neurons to mammalian Wnts -1, -4, -5a, -6, and -7b, and the Wnt inhibitors sFRP -1, -2, and -3, were tested in vitro by growing SAG explants from embryonic day 4 (E4) chicken embryos for two days in 3D collagen gels. Average neurite length and density were quantified to determine effects on neurite outgrowth. SAG neurites were strongly repelled by human Sema... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808081 Thu, 21 Apr 2011 23:00:00 +0100 4808081 http://www.medworm.com/index.php?rid=4808078&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21540098%26dopt%3DAbstract Authors: Shepherd R, Verhoeven K, Xu J, Risi F, Fallon J, Wise A Experimental studies play an important role in establishing the safety and efficacy of cochlear implants and they continue to provide insight into a new generation of electrode arrays and stimulation strategies. One drawback has been the limited depth of insertion of an electrode array in experimental animals. We compared the insertion depth and trauma associated with the insertion of Cochlear Ltd's Hybrid-L (HL) array with a standard 8 ring array in cat cochleae. Both arrays were inserted into cadaver cochleae and an X-ray recorded their anatomical location. The implanted cochlea was serially sectioned and photographed at 300 μm intervals for evidence of electrode insertion trauma. Subsequently two cats were chronicall... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808078 Thu, 21 Apr 2011 23:00:00 +0100 4808078 http://www.medworm.com/index.php?rid=4808084&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21527325%26dopt%3DAbstract Authors: Wang H, Brozoski TJ, Caspary DM Tinnitus is a phantom auditory sensation experienced by up to 14% of the United States population with a smaller percentage experiencing decreased quality of life. A compelling hypothesis is that tinnitus results from a maladaptive plastic net down-regulation of inhibitory amino acid neurotransmission in the central auditory pathway. This loss of inhibition may be a compensatory response to loss of afferent input such as that caused by acoustic insult and/or age-related hearing loss, the most common causes of tinnitus in people. Compensatory plastic changes may result in pathologic neural activity that underpins tinnitus. The neural correlates include increased spontaneous spiking, increased bursting and decreased variance of inter-spike interva... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808084 Wed, 20 Apr 2011 23:00:00 +0100 4808084 http://www.medworm.com/index.php?rid=4808080&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21530629%26dopt%3DAbstract In this report, we will update the progress on these topics and indicate important issues still awaiting resolution. PMID: 21530629 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808080 Wed, 20 Apr 2011 23:00:00 +0100 4808080 http://www.medworm.com/index.php?rid=4808087&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21447376%26dopt%3DAbstract Authors: Zeng FG, Tang Q, Dimitrijevic A, Starr A, Larky J, Blevins NH Tinnitus is a phantom sensation of sound in the absence of external stimulation. However, external stimulation, particularly electric stimulation via a cochlear implant, has been shown to suppress tinnitus. Different from traditional methods of delivering speech sounds or high-rate (>2000 Hz) stimulation, the present study found a unique unilaterally-deafened cochlear implant subject whose tinnitus was completely suppressed by a low-rate (<100 Hz) stimulus, delivered at a level softer than tinnitus to the apical part of the cochlea. Taking advantage of this novel finding, the present study compared both event-related and spontaneous cortical activities in the same subject between the tinnitus-present and tin... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808087 Mon, 04 Apr 2011 23:00:00 +0100 4808087 http://www.medworm.com/index.php?rid=4808088&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21447375%26dopt%3DAbstract Authors: Grothe B, Koch U The initial binaural processing in the superior olive represents the fastest computation known in the entire mammalian brain. Although the binaural system has to perform under very different and often highly dynamic acoustic conditions, the integration of binaural information in the superior olivary complex (SOC) has not been considered to be adaptive or dynamic itself. Recent evidence, however, shows that the initial processing of interaural level and interaural time differences relies on well-adjusted interactions of both the excitatory and the inhibitory projections, respectively. Under static conditions, these inputs seem to be tightly balanced, but may also require dynamic adjustment for proper function when the acoustic environment changes. GABA(B) recep... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808088 Sat, 02 Apr 2011 23:00:00 +0100 4808088 http://www.medworm.com/index.php?rid=4808090&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21447373%26dopt%3DAbstract Authors: Osen KK, Furness DN, Hackney CM The transition between the central (CNS) and peripheral nervous system (PNS) in cranial and spinal nerve roots, referred to here as the CNS-PNS border, is of relevance to nerve root disorders and factors that affect peripheral-central regeneration. Here, this border is described in the cat cochlear nerve using light microscopical sections, and scanning electron microscopy of the CNS-PNS interfaces exposed by fracture of the nerve either prior to or following critical point drying. The CNS-PNS border represents an abrupt change in type of myelin, supporting elements, and vascularization. Because central myelin is formed by oligodendrocytes and peripheral myelin by Schwann cells, the myelinated fibers are as a rule equipped with a node of Ranvier ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808090 Fri, 01 Apr 2011 23:00:00 +0100 4808090 http://www.medworm.com/index.php?rid=4808089&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21447374%26dopt%3DAbstract Authors: Mazurek B, Amarjargal N, Haupt H, Fuchs J, Olze H, Machulik A, Gross J Oxidative stress is an important mechanism inducing ototoxicity-, age- and noise-induced hearing loss. To better understand this phenomenon, we examined cochlear tissues for the expression of following genes involved directly or indirectly in the oxidative stress response: glyceraldehyde-3-phosphate dehydrogenase (Gapdh); solute carrier family-2 (facilitated glucose transporter), member-1 (Slc2a1); heme oxygenase-1 (Hmox1); heme oxygenase-2 (Hmox2); inducible nitric oxide synthase-2 (Nos2); transferrin (Tf); transferrin receptor (Tfrc); glutathione S-transferase A3 (Gsta3) and metallothionein-1a (Mt1a). Cochlear tissues were dissected from the p3-p5 Wistar rats, divided into the organ of Corti (OC), modiolu... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808089 Fri, 01 Apr 2011 23:00:00 +0100 4808089 http://www.medworm.com/index.php?rid=4808085&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21463668%26dopt%3DAbstract Authors: Sanes DH, Kotak VC Functional inhibitory synapses form in auditory cortex well before the onset of normal hearing. However, their properties change dramatically during normal development, and many of these maturational events are delayed by hearing loss. Here, we review recent findings on the developmental plasticity of inhibitory synapse strength, kinetics, and GABAA receptor localization in auditory cortex. Although hearing loss generally leads to a reduction of inhibitory strength, this depends on the type of presynaptic interneuron. Furthermore, plasticity of inhibitory synapses also depends on the postsynaptic target. Hearing loss leads reduced GABAA receptor localization to the membrane of excitatory, but not inhibitory neurons. A reduction in normal activity in developm... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808085 Fri, 01 Apr 2011 23:00:00 +0100 4808085 http://www.medworm.com/index.php?rid=4808086&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21457768%26dopt%3DAbstract Authors: O'Connor KN, Johnson JS, Niwa M, Noriega NC, Marshall EA, Sutter ML Previous observations show that humans outperform non-human primates on some temporally-based auditory discrimination tasks, suggesting there are species differences in the proficiency of auditory temporal processing among primates. To further resolve these differences we compared the abilities of rhesus macaques and humans to detect sine-amplitude modulation (AM) of a broad-band noise carrier as a function of both AM frequency (2.5 Hz-2 kHz) and signal duration (50-800 ms), under similar testing conditions. Using a go/no-go AM detection task, we found that macaques were less sensitive than humans at the lower frequencies and shorter durations tested but were as, or slightly more, sensitive at higher freque... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808086 Tue, 29 Mar 2011 23:00:00 +0100 4808086 http://www.medworm.com/index.php?rid=4808091&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21439366%26dopt%3DAbstract Authors: Howgate S, Plack CJ It is well documented that exposure to recreational noise may result in a temporary threshold shift (TTS) due to cochlear dysfunction. A forward-masking paradigm was used to estimate the relative contribution of inner hair cell (IHC) and outer hair cell (OHC) dysfunction to TTS. Eighteen normal-hearing adults completed a test battery before, immediately after, and one week after attending a loud music venue. Personal dosimeters recorded mean equivalent exposure levels of 99.0 dB A. Shortly after exposure, there was an average TTS of 10.8 dB at 4 kHz, and an average reduction in the estimated gain provided by the OHCs of 11.5 dB. Gain reduction correlated significantly with TTS. The results suggest that OHC dysfunction can account almost entirely for th... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4808091 Wed, 23 Mar 2011 00:00:00 +0100 4808091 http://www.medworm.com/index.php?rid=4643325&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21420476%26dopt%3DAbstract Authors: Johnson SB, Schmitz HM, Santi PA Thin-sheet laser imaging microscopy (TSLIM) was used to serially section five whole cochleas from 4-wk-old CBA/JCr mice. Three-dimensional reconstructions of Rosenthal's canal (RC) were produced in order to measure canal length and volume, to generate orthogonal cross sections for area measurements, and to determine spiral ganglion neuron (SGN) number. RC length averaged 2.0 mm ± 0.04 (SEM) as measured along the centroid of the canal compared to an average basilar membrane (BM) length of 5.9 ± 0.05 (SEM). RC volume averaged 0.036 mm(3) ± 0.009 (SEM). Significant increases in the radial area of RC were observed at the base (13%), middle (62%), and apex (90%) of its length. The total number of spiral ganglion neurons (SGNs) in RC in ea... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643325 Mon, 21 Mar 2011 00:00:00 +0100 4643325 http://www.medworm.com/index.php?rid=4643328&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21414395%26dopt%3DAbstract Authors: Brown MR, Kaczmarek LK For accurate processing of auditory information, neurons in auditory brainstem nuclei have to fire at high rates with high temporal accuracy. These two requirements can only be fulfilled when the intrinsic electrical properties of these neurons are matched to the pattern of incoming synaptic stimulation. This review article focuses on three families of potassium channels that are critical to shaping the firing pattern and accuracy of neurons. Changes in the auditory environment can trigger very rapid changes in the phosphorylation state of potassium channels in auditory brainstem nuclei. Longer lasting changes in the auditory environment produce changes in the rates of translation and transcription of genes encoding these channels. A key protein that pla... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643328 Sat, 19 Mar 2011 00:00:00 +0100 4643328 http://www.medworm.com/index.php?rid=4643327&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21414396%26dopt%3DAbstract Authors: Guan X, Gan RZ Combined measurements of middle ear transfer function and auditory brainstem response (ABR) in live guinea pigs with middle ear effusion (MEE) are reported in this paper. The MEE model was created by injecting saline into the middle ear cavity. Vibrations of the tympanic membrane (TM), the tip of the incus, and the round window membrane (RWM) were measured with a laser vibrometer at frequencies of 0.2-40 kHz when the middle ear fluid increased from 0 to 0.2 ml (i.e., full fill of the cavity). The click and pure tone ABRs were recorded as the middle ear fluid increased. Fluid introduction reduced mobility of the TM, incus and RWM mainly at high frequencies (f > 1 kHz). The magnitude of this reduction was related to the volume of fluid. The displacement tr... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643327 Sat, 19 Mar 2011 00:00:00 +0100 4643327 http://www.medworm.com/index.php?rid=4643326&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21414397%26dopt%3DAbstract Authors: Yang T, Kersigo J, Jahan I, Pan N, Fritzsch B The bipolar spiral ganglion neurons predominantly delaminate from the growing cochlear duct and migrate to Rosenthal's canal. They project radial fibers to innervate the organ of Corti (type I neurons to inner hair cells, type II neurons to outer hair cells) and also project tonotopically to the cochlear nuclei. The early differentiation of these neurons requires transcription factors to regulate migration, pathfinding and survival. Neurog1 null mice lack formation of neurons. Neurod1 null mice show massive cell death combined with aberrant central and peripheral projections. Prox1 protein is necessary for proper type II neuron process navigation， which is also affected by the neurotrophins Bdnf and Ntf3. Neurotrophin null mutant... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643326 Sat, 19 Mar 2011 00:00:00 +0100 4643326 http://www.medworm.com/index.php?rid=4643324&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21426926%26dopt%3DAbstract Authors: Zhao Y, Rubio M, Tzounopoulos T A hallmark of brain organization is the integration of primary and modulatory pathways by principal neurons. Primary sensory inputs are usually not plastic, while modulatory inputs converging to the same principal neuron can be plastic. However, the mechanisms determining this input specific expression of synaptic plasticity remain unknown. We investigated this problem in the dorsal cochlear nucleus (DCN), where principal cells integrate primary auditory nerve input with plastic, parallel fiber input. Our previous DCN studies have shown that parallel fiber inputs exhibit short- and long-term plasticities mediated by endocannabinoid signaling. Here we show that auditory nerve inputs to principal cells do not show short- or long-term endocannabino... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643324 Sat, 19 Mar 2011 00:00:00 +0100 4643324 http://www.medworm.com/index.php?rid=4643323&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21426927%26dopt%3DAbstract Authors: Froemke RC, Martins AR The nervous system must dynamically represent sensory information in order for animals to perceive and operate within a complex, changing environment. Receptive field plasticity in the auditory cortex allows cortical networks to organize around salient features of the sensory environment during postnatal development, and then subsequently refine these representations depending on behavioral context later in life. Here we review the major features of auditory cortical receptive field plasticity in young and adult animals, focusing on modifications to frequency tuning of synaptic inputs. Alteration in the patterns of acoustic input, including sensory deprivation and tonal exposure, leads to rapid adjustments of excitatory and inhibitory strengths that coll... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643323 Sat, 19 Mar 2011 00:00:00 +0100 4643323 http://www.medworm.com/index.php?rid=4643322&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21426928%26dopt%3DAbstract Authors: Avan P, Giraudet F, Chauveau B, Gilain L, Mom T The presence of endolymphatic hydrops as a marker of Menière's disease (MD) suggests abnormal pressure in the intralabyrinthine compartments of patients and excessive stiffness of sound-sensitive structures. Otoacoustic emissions (OAEs) have been reported to respond to changes in the ear's stiffness, including those produced by intracranial pressure steps, by a characteristic phase shift around 1 kHz, thereby suggesting a noninvasive means of monitoring MD. Here, body tilt was used for modulating intracranial pressure in forty-one patients with definite MD who were tentatively measured at two stages, with and without active symptoms. Their distortion-product OAEs (DPOAEs) were dynamically monitored around 1 kHz every few seconds... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643322 Sat, 19 Mar 2011 00:00:00 +0100 4643322 http://www.medworm.com/index.php?rid=4643321&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21426929%26dopt%3DAbstract This study focuses on the characterization of the duration of this temporal memory and qualitative assessment of the associated response attenuation. Two experimental parameters - inter-stimulus interval (ISI) and repetition time (TR) - were varied during an fMRI experiment in which participants were asked to passively attend to an auditory stimulus. Results present evidence of a state-dependent interaction between induced responses. As expected, attenuating effects of these interactions become less significant as TR and ISI increase and in contrast to previous work, persist up to 18s after a stimulus presentation. PMID: 21426929 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643321 Sat, 19 Mar 2011 00:00:00 +0100 4643321 http://www.medworm.com/index.php?rid=4643330&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21397676%26dopt%3DAbstract Authors: Macleod KM Alterations in synaptic strength over short time scales, termed short-term synaptic plasticity, can gate the flow of information through neural circuits. Different information can be extracted from the same presynaptic spike train depending on the activity- and time-dependent properties of the plasticity at a given synapse. The parallel processing in the brain stem auditory pathways provides an excellent model system for investigating the functional implications of short-term plasticity in neural coding. We review recent evidence that short-term plasticity differs in different pathways with a special emphasis on the 'intensity' pathway. While short-term depression dominates the 'timing' pathway, the intensity pathway is characterized by a balance of short-term depre... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643330 Thu, 17 Mar 2011 00:00:00 +0100 4643330 http://www.medworm.com/index.php?rid=4643329&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21397677%26dopt%3DAbstract Authors: Kopp-Scheinpflug C, Steinert JR, Forsythe ID The aim of this review is to consider the various forms and functions of transmission across the calyx of Held/MNTB synapse and how its modulation might contribute to auditory processing. The calyx of Held synapse is the largest synapse in the mammalian brain which uses the conventional excitatory synaptic transmitter, glutamate. It is sometimes portrayed as the 'ultimate' in synaptic signalling: it is a synaptic relay in which a single axon forms one synaptic terminal onto one specific target neuron. Questions that are often raised are: "Why does such a large and secure synapse need any form of modulation? Surely it is built simply to guarantee firing an action potential in the target neuron? If this synapse is so secure, why is a ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4643329 Thu, 17 Mar 2011 00:00:00 +0100 4643329 http://www.medworm.com/index.php?rid=4528117&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21316436%26dopt%3DAbstract We report here on two additional experiments. First, we demonstrate suppression in both AI and AII upon exposure to 4-20 kHz bandlimited noise, thus generalizing our previous results obtained with tonal ensembles. However, we found a somewhat different suppression pattern with noise. Whereas 4-20 kHz tone exposure produced relatively uniform suppression over the 4-20 kHz range, save for a small local minimum at ∼10 kHz, 4-20 kHz noise produced maximal suppression over ∼4-10 kHz, which then progressively weakened with frequency up to 20 kHz. Second, we outline the time course of the emergence of response suppression in AI, using the above-mentioned pair of third-octave bands as the exposure stimulus. Suppression emerged relatively rapidly, within a week of exposure onset, and was... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4528117 Thu, 17 Feb 2011 00:00:00 +0100 4528117 http://www.medworm.com/index.php?rid=4528116&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21329750%26dopt%3DAbstract Authors: Patuzzi R This paper reviews some of what is known about ion transport through the cells of the mammalian stria vascularis, and discusses how the endolymph and endocochlear potential in scala media are produced by the stria's main cell types. It discusses the role of each cells' ion transport proteins from an engineering perspective, and the advantages and disadvantages in using the different transport proteins in the different cells to perform their different roles. To aid this discussion, the use of spreadsheet analysis in the modelling of ion transport in single cells and homogenous epithelia is outlined, including the current-voltage (IV) characteristics of the three main categories of transport proteins (pores, ports and pumps), and the constraint equations that apply und... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4528116 Mon, 14 Feb 2011 00:00:00 +0100 4528116 http://www.medworm.com/index.php?rid=4528115&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21329751%26dopt%3DAbstract Authors: Richter CP, Kumar G, Webster E, Banas SK, Whitlon DS Accurate counting of neurons in the cochlea has a significant impact on the interpretation of research and clinically relevant data. However, reports of numbers of neurons in the spiral ganglion are widely variable across studies, even within the same species. We suggest that the implementation of a more standardized, unbiased counting method will improve the consistency and accuracy of neuron counts and will impact scientific interpretations. To test this view, we compared, in different ways, the numbers of neurons in the spiral ganglia of developing gerbils, previously reported to decrease by 22-27% between birth and age 7 days. Cochleae from gerbils, aged newborn, 7 days, 20 days, 1.5 years and 2.5 years were embedded in ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4528115 Mon, 14 Feb 2011 00:00:00 +0100 4528115 http://www.medworm.com/index.php?rid=4473142&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21310226%26dopt%3DAbstract Authors: O'Neil JN, Connelly CJ, Limb CJ, Ryugo DK The auditory experience is crucial for the normal development and maturation of brain structure and the maintenance of the auditory pathways. The specific aims of this review are (i) to provide a brief background of the synaptic morphology of the endbulb of Held in hearing and deaf animals; (ii) to argue the importance of this large synaptic ending in linking neural activity along ascending pathways to environmental acoustic events; (iii) to describe how the re-introduction of electrical activity changes this synapse; and (iv) to examine how changes at the endbulb synapse initiate trans-synaptic changes in ascending auditory projections to the superior olivary complex, the inferior complex, and the auditory cortex. PMID: 21310226 [... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473142 Mon, 07 Feb 2011 00:00:00 +0100 4473142 http://www.medworm.com/index.php?rid=4473143&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21303689%26dopt%3DAbstract Authors: Osmanski MS, Wang X The common marmoset is a small, arboreal, New World primate that has emerged as a promising non-human model system in auditory neuroscience. A complete understanding of the neuroethology of auditory processing in marmosets will include behavioral work examining how sounds are perceived by these animals. However, there have been few studies of the marmoset‟s hearing and perceptual abilities and the audiogram of this species has not been measured using modern psychophysical methods. The present experiment pairs psychophysics with an operant conditioning technique to examine perception of pure tone stimuli by marmosets using an active behavioral paradigm. Subjects were trained to lick at a feeding tube when they detected a sound. Correct responses provided a... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473143 Sat, 05 Feb 2011 00:00:00 +0100 4473143 http://www.medworm.com/index.php?rid=4473144&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21296136%26dopt%3DAbstract Authors: Grimsley JM, Palmer AR, Wallace MN Many communication calls contain information about the physical characteristics of the calling animal. During maturation of the guinea pig purr call the pitch becomes lower as the fundamental frequency progressively decreases from 476 to 261 Hz on average. Neurons in the primary auditory cortex (AI) often respond strongly to the purr and we postulated that some of them are capable of distinguishing between purr calls of different pitch. Consequently four pitch-shifted versions of a single call were used as stimuli. Many units in AI (79/182) responded to the purr call either with an onset response or with multiple bursts of firing that were time-locked to the phrases of the call. All had a characteristic frequency ≤ 5 kHz. Both types of unit... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473144 Thu, 03 Feb 2011 00:00:00 +0100 4473144 http://www.medworm.com/index.php?rid=4473146&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21291978%26dopt%3DAbstract Authors: Canlon B PMID: 21291978 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473146 Wed, 02 Feb 2011 00:00:00 +0100 4473146 http://www.medworm.com/index.php?rid=4473145&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21295127%26dopt%3DAbstract Authors: Nakagawa T Prostaglandins are one of the major groups of chemical mediators in the mammalian body. Among prostaglandins, prostaglandin E2 (PGE2) is the most abundant prostanoid in humans and involved in regulating many different fundamental biological functions. PGE2 signaling is mediated by four distinct E-prostanoid receptors (EPs) namely EP1-4. Recently, accumulating evidence indicates critical, but complex roles of EP signaling in the pathogenesis of neuronal diseases depending on the context of neuronal injury. Four distinct EPs are expressed in the stria vascularis, spiral ligament, spiral ganglion and organ of Corti, indicating an involvement of EP signaling in the cochlear function. Activation of EP4 in cochleae significantly attenuates noise-induced damage in cochleae... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473145 Tue, 01 Feb 2011 00:00:00 +0100 4473145 http://www.medworm.com/index.php?rid=4473147&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21281707%26dopt%3DAbstract Authors: Chen WC, Xue HZ, Hsu YL, Liu Q, Patel S, Davis RL As with other elements of the peripheral auditory system, spiral ganglion neurons display specializations that vary as a function of location along the tonotopic axis. Previous work has shown that voltage-gated K(+) channels and synaptic proteins show graded changes in their density that confers rapid responsiveness to neurons in the high frequency, basal region of the cochlea and slower, more maintained responsiveness to neurons in the low frequency, apical region of the cochlea. In order to understand how voltage-gated calcium channels (VGCCs) may contribute to these diverse phenotypes, we identified the VGCC α-subunits expressed in the ganglion, investigated aspects of Ca(2+)-dependent neuronal firing patterns, and mapped t... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473147 Mon, 31 Jan 2011 00:00:00 +0100 4473147 http://www.medworm.com/index.php?rid=4473151&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21276841%26dopt%3DAbstract Authors: Mann ZF, Kelley MW Acoustic frequency analysis plays an essential role in sound perception, communication and behavior. The auditory systems of most vertebrates that perceive sounds in air are organized based on the separation of complex sounds into component frequencies. This process begins at the level of the auditory sensory epithelium where specific frequencies are distributed along the tonotopic axis of the mammalian cochlea or the avian/reptilian basilar papilla (BP). Mechanical and electrical mechanisms mediate this process, but the relative contribution of each mechanism differs between species. Developmentally, structural and physiological specializations related to the formation of a tonotopic axis form gradually over an extended period of time. While some aspects of... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473151 Thu, 27 Jan 2011 00:00:00 +0100 4473151 http://www.medworm.com/index.php?rid=4473150&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21276842%26dopt%3DAbstract Authors: Couchman K, Garrett A, Deardorff AS, Rattay F, Resatz S, Fyffe R, Walmsley B, Leão RN The development of cochlear ilmplants for the treatment of patients with profound hearing loss has advanced considerably in the last few decades, particularly in the field of speech comprehension. However, attempts to provide not only sound decoding but also spatial hearing are limited by our understanding of circuit adaptations in the absence of auditory input. Here we investigate the lateral superior olive (LSO), a nucleus involved in interaural level difference (ILD) processing in the auditory brainstem using a mouse model of congenital deafness (the dn/dn mouse). An electrophysiological investigation of principal neurons of the LSO from the dn/dn mouse reveals a higher than normal propor... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473150 Thu, 27 Jan 2011 00:00:00 +0100 4473150 http://www.medworm.com/index.php?rid=4473149&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21276843%26dopt%3DAbstract Authors: Davis RL, Liu Q Spiral ganglion neurons are the first neural element of the auditory system. They receive precise synaptic signals which represent features of sound stimuli encoded by hair cell receptors and they deliver a digital representation of this information to the central nervous system. It is well known that spiral ganglion neurons are selectively responsive to specific sound frequencies, and that numerous structural and physiological specializations in the inner ear increase the quality of this tuning, beyond what could be accomplished by the passive properties of the basilar membrane. Further, consistent with what we know about other sensory systems, it is becoming clear that the parallel divergent innervation pattern of type I spiral ganglion neurons has the potent... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473149 Thu, 27 Jan 2011 00:00:00 +0100 4473149 http://www.medworm.com/index.php?rid=4473148&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21276844%26dopt%3DAbstract Authors: Riecke L, Micheyl C, Vanbussel M, Schreiner CS, Mendelsohn D, Formisano E An interrupted sound can be perceived as continuous when noise masks the interruption, creating an illusion of continuity. Recent findings have shown that adaptor sounds preceding an ambiguous target sound can influence listeners' rating of target continuity. However, it remains unclear whether these aftereffects on perceived continuity influence sensory processes, decisional processes (i.e., criterion shifts), or both. The present study addressed this question. Results show that the target sound was more likely to be rated as 'continuous' when preceded by adaptors that were perceived as clearly discontinuous than when it was preceded by adaptors that were heard (illusorily or veridically) as continuous.... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473148 Thu, 27 Jan 2011 00:00:00 +0100 4473148 http://www.medworm.com/index.php?rid=4473153&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21272629%26dopt%3DAbstract Authors: Shen H, Lin Z, Lei D, Han J, Ohlemiller KK, Bao J There is presently no clearly effective preventative medication against noise-induced hearing loss (NIHL). However, negative feedback systems that presumably evolved to modulate the sensitivity of the organ of Corti may incidentally confer protection. One feedback system implicated in protection from NIHL involves synaptic connections between the lateral olivocochlear efferent terminals and the afferent fibers of spiral ganglion neurons (SGNs). These connections operate via high-affinity nicotinic acetylcholine receptors containing the β2 subunit. We unexpectedly observed protection from NIHL in 9-month old knockout mice lacking the β2 subunit (β2(-/-)); however, the same protection was not observed in 2-month old β2(-/-) m... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473153 Tue, 25 Jan 2011 00:00:00 +0100 4473153 http://www.medworm.com/index.php?rid=4473152&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21272630%26dopt%3DAbstract Authors: Hsieh IH, Petrosyan A, Gonçalves OF, Hickok G, Saberi K The auditory system can encode interaural delays in highpass-filtered complex sounds by phase locking to their slowly modulating envelopes. Spectrotemporal analysis of interaurally time-delayed highpass waveforms reveals the presence of a concomitant interaural level cue. The current study systematically investigated the contribution of time and concomitant level cues carried by positive and negative envelope slopes of a modified sinusoidally amplitude-modulated (SAM) high-frequency carrier. The waveforms were generated from concatenation of individual modulation cycles whose envelope peaks were extended by the desired interaural delay, allowing independent control of delays in the positive and negative modulation slopes... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4473152 Tue, 25 Jan 2011 00:00:00 +0100 4473152 http://www.medworm.com/index.php?rid=4406376&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21256948%26dopt%3DAbstract Authors: Fritzsch B, Jahan I, Pan N, Kersigo J, Duncan J, Kopecky B This review summarizes recent progress in our understanding of the molecular basis of cochlear duct growth, specification of the organ of Corti, and differentiation of the different types of hair cells. Studies of multiple mutations suggest that developing hair cells are involved in stretching the organ of Corti through convergent extension movements.However, Atoh1 null mutants have only undifferentiated and dying organ of Corti precursors but show a near normal extension of the cochlear duct, implying that organ of Corti precursor cells can equally drive this process. Some factors influence cochlear duct growth by regulating the cell cycle and proliferation. Shortened cell cycle and premature cell cycle exit can lead ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4406376 Thu, 20 Jan 2011 00:00:00 +0100 4406376 http://www.medworm.com/index.php?rid=4406377&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21251965%26dopt%3DAbstract Authors: Staecker H, Praetorius M, Brough DE Despite the significant impact of hearing and balance disorders on the general population there are currently no dedicated pharmaceuticals that target the inner ear. Advances in molecular biology and neuroscience have improved our understanding of the inner ear allowing the development of a range of molecular targets that have the potential to treat both hearing and balance disorders. One of the principal advantages of the inner ear is that it is accessible through a variety of approaches that would allow a potential to be delivered locally rather than systemically. This significantly broadens the potential medications that can be developed and opens the possibility of local gene delivery as a therapeutic intervention. Several potential clin... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4406377 Mon, 17 Jan 2011 00:00:00 +0100 4406377 http://www.medworm.com/index.php?rid=4406378&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21238563%26dopt%3DAbstract In this study, to elucidate the perception mechanism, the masking of bone-conducted ultrasound (BCU) produced by ACAS and the sensitivity of BCU in hearing impaired subjects were evaluated. We found that BCU was masked by high frequency ACAS, especially in the frequency range of 10-14 kHz. The most effective masker frequency depended on masker intensity. For hearing impaired subjects, the pure tone thresholds at 1-8 kHz and the maximum audible frequencies at cut-off intensities of 70-100 dB HL were significantly associated with the BCU threshold (p < 0.01 or p < 0.05). No subjects with estimated total loss of the inner hair cell system in the cochlear basal turn could hear BCU. These results suggest the peripheral perceptual region to be located in the cochlea. The results of masking... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4406378 Fri, 14 Jan 2011 00:00:00 +0100 4406378 http://www.medworm.com/index.php?rid=4406381&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21236325%26dopt%3DAbstract Authors: Buchholz JM Coloration detection thresholds (CDTs) were measured for a single reflection as a function of spectral content and reflection delay for diotic stimulus presentation. The direct sound was a 320-ms long burst of bandpass-filtered noise with varying lower and upper cut-off frequencies. The resulting threshold data revealed that: (1) sensitivity decreases with decreasing bandwidth and increasing reflection delay and (2) high-frequency components contribute less to detection than low-frequency components. The auditory processes that may be involved in coloration detection (CD) are discussed in terms of a spectrum-based auditory model, which is conceptually similar to the pattern-transformation model of pitch (Wightman, 1973). Hence, the model derives an auto-correlation... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4406381 Wed, 12 Jan 2011 00:00:00 +0100 4406381 http://www.medworm.com/index.php?rid=4406379&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21236327%26dopt%3DAbstract Authors: Moore BC, Gockel HE This paper reviews methods that have been used to estimate the resolvability of individual partials in harmonic and inharmonic complex tones and considers the implications of the results for theories of pitch perception. The methods include: requiring comparisons of the pitch of an isolated pure tone and a partial within a complex tone as a measure of the ability to "hear out" that partial; considering the magnitude of ripples in the calculated excitation pattern of a complex tone; using a complex tone as a forward masker and using ripples in the masking pattern to estimate resolvability; measuring sensitivity to the relative phase of the components within complex tones. The measures are broadly consistent in indicating that harmonics with numbers up to abo... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4406379 Wed, 12 Jan 2011 00:00:00 +0100 4406379 http://www.medworm.com/index.php?rid=4406380&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21236326%26dopt%3DAbstract Authors: Manley GA, Fuchs PA PMID: 21236326 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=4406380 Tue, 11 Jan 2011 00:00:00 +0100 4406380 http://www.medworm.com/index.php?rid=4342379&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21223997%26dopt%3DAbstract Authors: Schreiner CE PMID: 21223997 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342379 Sat, 08 Jan 2011 00:00:00 +0100 4342379 http://www.medworm.com/index.php?rid=4342380&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21195755%26dopt%3DAbstract Authors: Dai C, Fridman GY, Della Santina CC To investigate the effects of vestibular prosthesis electrode implantation and activation on hearing in rhesus monkeys, we measured auditory brainstem responses (ABR) and distortion product otoacoustic emissions (DPOAE) in four rhesus monkeys before and after unilateral implantation of vestibular prosthesis electrodes in each of 3 left semicircular canals (SCC). Each of the 3 left SCCs were implanted with electrodes via a transmastoid approach. Right ears, which served as controls, were not surgically manipulated. Hearing tests were conducted before implantation (BI) and then 4 weeks post-implantation both without electrical stimulation (NS) and with electrical stimulation (S). During the latter condition, prosthetic electrical stimuli encod... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342380 Fri, 31 Dec 2010 00:00:00 +0100 4342380 http://www.medworm.com/index.php?rid=4342383&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21195150%26dopt%3DAbstract Authors: Schofield BR, Motts SD, Mellott JG Acetylcholine (ACh) is a neuromodulator that is likely to play a role in plasticity as well as other phenomena at many sites in the auditory system. The auditory cortex receives cholinergic innervation from the basal forebrain, whereas the cochlea receives cholinergic innervation from the superior olivary complex. Much of the remainder of the auditory pathways receives innervation from the pedunculopontine and laterodorsal tegmental nuclei, two nuclei referred to collectively as the pontomesencephalic tegmentum (PMT). The PMT provides the major source of ACh to the auditory thalamus and the midbrain, and is a substantial source (in addition to the superior olivary complex) of ACh in the cochlear nucleus. Individual cholinergic cells in the PM... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342383 Thu, 30 Dec 2010 00:00:00 +0100 4342383 http://www.medworm.com/index.php?rid=4342384&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21194561%26dopt%3DAbstract Authors: Schreiner CE, Cant NB PMID: 21194561 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342384 Wed, 29 Dec 2010 00:00:00 +0100 4342384 http://www.medworm.com/index.php?rid=4342392&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21187135%26dopt%3DAbstract Authors: Hurley LM, Hall IC Context-dependent plasticity in auditory processing is achieved in part by physiological mechanisms that link behavioral state to neural responses to sound. The neuromodulator serotonin has many characteristics suitable for such a role. Serotonergic neurons are extrinsic to the auditory system but send projections to most auditory regions. These projections release serotonin during particular behavioral contexts. Heightened levels of behavioral arousal and specific extrinsic events, including stressful or social events, increase serotonin availability in the auditory system. Although the release of serotonin is likely to be relatively diffuse, highly specific effects of serotonin on auditory neural circuitry are achieved through the localization of serotoner... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342392 Sat, 25 Dec 2010 00:00:00 +0100 4342392 http://www.medworm.com/index.php?rid=4342391&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21187136%26dopt%3DAbstract Authors: Wersinger E, Fuchs PA Outer hair cells (OHCs) amplify the sound-evoked motion of the basilar membrane to enhance acoustic sensitivity and frequency selectivity. Medial olivocochlear (MOC) efferents inhibit OHCs to reduce the sound-evoked response of cochlear afferent neurons. OHC inhibition occurs through the activation of post-synaptic α9α10 nicotinic receptors tightly coupled to calcium-dependent SK2 channels that hyperpolarize the hair cell. MOC neurons are cholinergic but a number of other neurotransmitters and neuromodulators have been proposed to participate in efferent transmission, with emerging evidence for both pre- and post-synaptic effects. Cochlear inhibition in vivo is maximized by repetitive activation of the efferents, reflecting facilitation and summation of... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342391 Sat, 25 Dec 2010 00:00:00 +0100 4342391 http://www.medworm.com/index.php?rid=4342390&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21187137%26dopt%3DAbstract Authors: Gratton MA, Eleftheriadou A, Garcia J, Verduzco E, Martin GK, Lonsbury-Martin BL, Vázquez AE The molecular mechanisms underlying the vast differences between individuals in their susceptibility to noise-induced hearing loss (NIHL) are unknown. The present study demonstrated that the effects of noise over-exposure on the expression of molecules likely to be important in the development of NIHL differ among inbred mouse strains having distinct susceptibilities to NIHL including B6 (B6.CAST) and 129 (129X1/SvJ and 129S1/SvImJ) mice. The noise-exposure protocol produced a loss of 40 dB in hearing sensitivity in susceptible B6 mice, but no loss for the two resistant 129 substrains. Analysis of gene expression in the membranous labyrinth 6 h following noise exposure revealed upre... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342390 Sat, 25 Dec 2010 00:00:00 +0100 4342390 http://www.medworm.com/index.php?rid=4342396&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21185928%26dopt%3DAbstract Authors: Anderson LA, Linden JF The auditory thalamic area includes the medial geniculate body (MGB) and the lateral part of the posterior thalamic nucleus (Pol). The MGB can be subdivided into a ventral subdivision, forming part of the lemniscal (primary) auditory pathway, and medial and dorsal subdivisions, traditionally considered (alongside the Pol) part of the non-lemniscal (secondary) pathway. However, physiological studies of the auditory thalamus have suggested that the Pol may be more appropriately characterised as part of the lemniscal pathway, while the medial MGB may be part of a third (polysensory) pathway, with characteristics of lemniscal and non-lemniscal areas. We document physiological properties of neurons in histologically identified areas of the MGB and Pol in the ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342396 Fri, 24 Dec 2010 00:00:00 +0100 4342396 http://www.medworm.com/index.php?rid=4342393&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21185929%26dopt%3DAbstract Authors: Latoche JR, Neely HR, Noben-Trauth K Progressive sensorineural hearing loss in humans is a common and debilitating impairment. Sensorineural deafness in inbred strains of mice is a similarly common and genetically diverse phenotype providing experimental models to study the underlying genetics and the biological effects of the risk factors. Here, we report that ALR/LtJ mice develop early-onset profound sensorineural hearing loss as evidenced by high-to-low frequency hearing threshold shifts, absent distortion-product otoacoustic emissions, and normal endocochlear potentials. Linkage analyses of a segregating backcross revealed three novel quantitative trait loci named sensorineural hearing loss (Snhl) -2, -3, and -4. The QTLs achieved very high LOD scores with markers on chrom... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342393 Fri, 24 Dec 2010 00:00:00 +0100 4342393 http://www.medworm.com/index.php?rid=4342399&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21184817%26dopt%3DAbstract Authors: Lee CC, Sherman SM Auditory forebrain pathways exhibit several morphological and physiological properties that underlie their specific neurobiological roles in auditory processing. Anatomically, such projections can be distinguished by their terminal size, arborization patterns, and postsynaptic dendritic locations. These structural features correlate with several postsynaptic physiological properties, such as EPSP amplitude, short-term plasticity, and postsynaptic receptor types. Altogether, these synaptic properties segregate into two main classes that are associated with either primarily information-bearing (Class 1) or modulatory (Class 2) roles, and have been used to delineate the principle routes of information flow through the auditory midbrain, thalamus, and cortex. Mo... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342399 Wed, 22 Dec 2010 00:00:00 +0100 4342399 http://www.medworm.com/index.php?rid=4342398&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21184818%26dopt%3DAbstract Authors: Wang M, Wu X, Li L, Schneider BA Duration thresholds for detecting a change in interaural correlation (from 0 to 1, or from 1 to 0) in the initial portion of a 1-second, broadband noise (0-10 kHz) were determined for younger and older adults in a two-interval, two-alternative forced choice paradigm as a function of the interaural delay between the noise bursts presented to each ear. When the interaural delay was 0 ms, older adults found it harder to detect a change in correlation from 0 to 1 than from 1 to 0. For younger adults, however, this pattern was reversed. For interaural delays greater than 0 ms, both younger adults and older adults found it easier to detect a change in interaural correlation from 0 to 1 for short interaural delays (1 ms) with the reverse being tru... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342398 Wed, 22 Dec 2010 00:00:00 +0100 4342398 http://www.medworm.com/index.php?rid=4342400&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21168479%26dopt%3DAbstract Authors: Garadat SN, Pfingst BE Gap detection threshold (GDT) is a commonly used measure of temporal acuity in cochlear-implant (CI) recipients. This measure, like other measures of temporal acuity, shows considerable variation across subjects and also varies across stimulation sites within subjects. The aims of this study were (1) to determine whether across-site variation in GDTs would be reduced or maintained with increased stimulation levels; (2) to determine whether across-site variation in GDTs at low stimulation levels was related to differences in loudness percepts at those same levels; and (3) to determine whether matching loudness levels could reduce across-site differences in GDTs. Thresholds and maximum comfortable loudness levels were measured in postlingually deaf adults ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342400 Fri, 17 Dec 2010 00:00:00 +0100 4342400 http://www.medworm.com/index.php?rid=4342403&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21167923%26dopt%3DAbstract Authors: Krishnan A, Plack CJ Psychoacoustic studies have shown that complex tones containing resolved harmonics evoke stronger pitches than complex tones with only unresolved harmonics. Also, unresolved harmonics presented in alternating sine and cosine (ALT) phase produce a doubling of pitch. We examine here whether the temporal pattern of phase-locked neural activity reflected in the scalp recorded human frequency following response (FFR) preserves information relevant to pitch strength, and to the doubling of pitch for ALT stimuli. Results revealed stronger neural periodicity strength for resolved stimuli, although the effect of resolvability was weak compared to the effect observed behaviorally; autocorrelation functions and FFR spectra suggest a different pattern of phase-locked ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342403 Thu, 16 Dec 2010 00:00:00 +0100 4342403 http://www.medworm.com/index.php?rid=4342402&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21167924%26dopt%3DAbstract Authors: Massida Z, Belin P, James C, Rouger J, Fraysse B, Barone P, Deguine O The human voice is important for social communication because voices carry speech and other information such as a person's physical characteristics and affective state. Further restricted temporal cortical regions are specifically involved in voice processing. In cochlear-implanted deaf patients, the processor alters the spectral cues which are crucial for the perception of the paralinguistic information of human voices. The aim of this study was to assess the abilities of voice discrimination in cochlear-implant (CI) users and in normal-hearing subjects (NHS) using a CI simulation (vocoder). In NHS the performance in voice discrimination decreased when reducing the spectral information by decreasing the num... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342402 Thu, 16 Dec 2010 00:00:00 +0100 4342402 http://www.medworm.com/index.php?rid=4342401&cid=s_35614_161_f&fid=35614&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21167925%26dopt%3DAbstract Authors: Carpinelli MR, Wise AK, Burt RA Klotho-deficient mice exhibit a premature aging syndrome, a feature of which is mild hearing loss. In the present study, the hearing phenotype of Klotho mice was characterized to better determine how well this phenotype resembles presbycusis in humans. It was demonstrated that Klotho animals have auditory-evoked brainstem response (ABR) threshold shifts of 14-18 dB in response to pure tone stimuli of 4, 8, 16 and 32 kHz, and similarly, in response to clicks; however, cochlear histology and spiral ganglion neuron density appeared normal in these mice. It was further demonstrated that a vitamin D-deficient diet normalizes serum calcitriol (1,25(OH)(2)D(3)) levels and prevents hearing loss in Klotho mice. It is concluded that hearing loss in Klot... Hearing Research journals http://www.medworm.com/rss/comments.php?id=4342401 Thu, 16 Dec 2010 00:00:00 +0100 4342401