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. Fri, 19 Mar 2010 17:47:07 +0100 http://www.medworm.com/index.php?rid=3380973&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%3D20233603%26dopt%3DAbstract Authors: Deike S, Scheich H, Brechmann A An important aspect of auditory scene analysis is the sequential grouping of similar sounds into one "auditory stream" while keeping competing streams separate. In the present low-noise fMRI study we presented sequences of alternating high-pitch (A) and low-pitch (B) complex harmonic tones using acoustic parameters that allow the perception of either two separate streams or one alternating stream. However, the subjects were instructed to actively and continuously segregate the A from the B stream. This was controlled by the additional instruction to listen for rare level deviants only in the low-pitched stream. Compared to the control condition in which only one non-separable stream was presented the active segregation of the A from the B stream... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3380973 Sat, 13 Mar 2010 00:00:00 +0100 3380973 http://www.medworm.com/index.php?rid=3374509&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%3D20227475%26dopt%3DAbstract Authors: Voss SE, Adegoke MF, Horton NJ, Sheth KN, Rosand J, Shera CA Several studies have demonstrated that the auditory system is sensitive to changes in posture, presumably through changes in intracranial pressure (ICP) that in turn alter the intracochlear pressure, which affects the stiffness of the middle-ear system. This observation has led to efforts to develop an ear-canal based noninvasive diagnostic measure for monitoring ICP, which is currently monitored invasively via access through the skull or spine. Here, we demonstrate the effects of postural changes, and presumably ICP changes, on distortion product otoacoustic emissions (DPOAE) magnitude, DPOAE angle, and power reflectance. Measurements were made on 12 normal-hearing subjects in two postural positions: upright at 90 d... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3374509 Thu, 11 Mar 2010 00:00:00 +0100 3374509 http://www.medworm.com/index.php?rid=3374508&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%3D20227476%26dopt%3DAbstract Authors: Strimbu CE, Kao A, Tokuda J, Ramunno-Johnson D, Bozovic D Spontaneous oscillations, one of the signatures of the active process in non-mammalian hair cells, have been shown to occur in individual hair bundles that have been fully decoupled from the overlying membrane. Here we use semi-intact preparations of the bullfrog sacculus to demonstrate that under more natural loading conditions, innate oscillations are suppressed by the presence of the overlying otolithic membrane, indicating that hair bundles lie in the quiescent rather than the unstable regime. Transepithelial electrical stimulation was then used to test the effect of evoking entrained hair bundle movement with an external stimulus. Firstly, we used a preparation in which the otolithic membrane has been partially det... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3374508 Thu, 11 Mar 2010 00:00:00 +0100 3374508 http://www.medworm.com/index.php?rid=3374507&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%3D20227477%26dopt%3DAbstract Authors: Clavier OH, Norris JA, Dietz AJ The nonlinear response of the ear to air-conducted sound has been studied to some depth. However, the nonlinear response of the ear to bone-conducted sound has received less attention. A comparison of the nonlinear response of humans to air and bone conducted sound is presented. Two different human subject test techniques were combined in this investigation. The first was a psychoacoustic investigation measuring the perceived cancellation of a bone-conducted sound stimulus with another air-conducted sound stimulus. The measurement was accomplished through a loudness-matching technique. The second investigation used distortion product otoacoustic emissions (DPOAEs) to make objective measurements of the response of the ear to both air-conducted so... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3374507 Thu, 11 Mar 2010 00:00:00 +0100 3374507 http://www.medworm.com/index.php?rid=3355073&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%3D20214971%26dopt%3DAbstract Authors: Chen GD, Kermany MH, D'Elia A, Ralli M, Tanaka C, Bielefeld EC, Ding D, Henderson D, Salvi R Aspirin has been extensively used in clinical settings. Its side effects on auditory function, including hearing loss and tinnitus, are considered as temporary. A recent promising finding is that chronic treatment with high-dose salicylate (the active ingredient of aspirin) for several weeks enhances expression of the outer hair cell (OHC) motor protein (prestin), resulting in strengthened OHC electromotility and enhanced distortion product otoacoustic emissions (DPOAE). To follow up on these observations, we carried out two studies, one planned study of age-related hearing loss restoration and a second unrelated study of salicylate-induced tinnitus. Rats of different strains and ages ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3355073 Sat, 06 Mar 2010 00:00:00 +0100 3355073 http://www.medworm.com/index.php?rid=3355074&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%3D20206676%26dopt%3DAbstract Authors: Song Y, Mellott JG, Winer JA Brain neural activity depends critically on the blood supply to a given structure. The blood supply can differ within and between divisions, which may have functional significance. We analyzed the microvascular organization of the cat inferior colliculus (IC) to determine if the capillary distribution is homogenous throughout.The IC consists of the central nucleus (CN), the dorsal cortex (DC), and the lateral cortex (LC), each with different roles in auditory behavior and perception.Plastic-embedded tissue was studied from adult cats in 1 mum-thick semithin sections stained with toluidine blue; tissue was sampled from the IC in a caudal-rostral series of sections.The architectonic subdivisions were drawn independently based on Golgi impregnations. ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3355074 Wed, 03 Mar 2010 00:00:00 +0100 3355074 http://www.medworm.com/index.php?rid=3340148&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%3D20197084%26dopt%3DAbstract Authors: Gnansia D, Pressnitzer D, Péan V, Meyer B, Lorenzi C Speech intelligibility is degraded in the presence of a competing talker for cochlear implantees, presumably because of impaired tracking and integration of speech segments glimpsed in the masker valleys. This hypothesis was tested by assessing the intelligibility of periodically-interrupted bisyllables produced by a male and female talker, for normal-hearing listeners and implantees. A 4-Hz square-wave modulator with random phase was used to interrupt bisyllables from each talker. Stimuli were either presented alone (Experiment I) or interleaved (Experiment II: the two talkers were alternated). In experiment I, the mean identification score for each voice was 88% for normal-hearing listeners, and 35% for implantees. In... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3340148 Sat, 27 Feb 2010 00:00:00 +0100 3340148 http://www.medworm.com/index.php?rid=3340149&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%3D20193750%26dopt%3DAbstract This study proposes a straightforward method for determining an absolute field calibration of a Radio Ear B71 bone driver, found by measuring the electrical input impedance of the transducer loaded by known masses. This absolute calibration is based upon a circuit model of the driver, describing it with three frequency-dependent parameters. Once these three parameters are known, measurements of the driver input voltage and current may be used to determine arbitrary mechanical load impedances (such as the in situ mastoid impedance), and thus the frequency dependence of the transmitted energy. The results of the proposed calibration method are validated by comparison with direct mechanical measurements using specialized equipment not available in the clinic, and a refined bone driver circuit... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3340149 Fri, 26 Feb 2010 00:00:00 +0100 3340149 http://www.medworm.com/index.php?rid=3322715&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%3D20184947%26dopt%3DAbstract Authors: Palmgren B, Jin Z, Ma H, Jiao Y, Olivius P Hearing impairment can be caused by a primary lesion to the spiral ganglion neurons (SGNs) with the hair cells kept intact, for example via tumours, trauma or auditory neuropathy. To mimic these conditions in animal models various methods of inflicting damage to the inner ear have been used. However, only a few methods have a selective effect on the SGNs, which is of importance since it might be clinically more relevant to study hearing impairment with the hair cells undamaged. beta-Bungarotoxin is a venom of the Taiwan banded krait, which in vitro has been shown to induce apoptosis in neurons, leaving remaining cochlear cells intact. We wanted to create an in vivo rat model of selective damage to primary auditory neurons. Under deep ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3322715 Mon, 22 Feb 2010 00:00:00 +0100 3322715 http://www.medworm.com/index.php?rid=3322714&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%3D20184948%26dopt%3DAbstract Authors: Wang WH, Yang JJ, Lin YC, Yang JT, Li SY Mutations of the GJB4 gene, encoding connexin 30.3 (Cx30.3), are associated with skin disorders. Recently, this gene was also detected in deaf individuals without skin disorders. However, the functional roles of Cx30.3 in the cochlea remain unclear. A primary step toward understanding the role of Cx30.3 in hearing and its dysfunction is the documentation of its cellular and sub-cellular locations within the cochlea. In the present study, we located and determined the cellular expression of Cx30.3 within the rat cochlea by using a polyclonal anti-Cx30.3 antibody. Expression of the Cx30.3 protein was detected in the spiral limbus, spiral ligament, spiral ganglion, and stria vascularis by immunohistochemistry and reverse transcription-poly... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3322714 Mon, 22 Feb 2010 00:00:00 +0100 3322714 http://www.medworm.com/index.php?rid=3322713&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%3D20184949%26dopt%3DAbstract Authors: Wesolek CM, Koay G, Heffner RS, Heffner HE The ability of Norway rats to use binaural time- and intensity-difference cues to localize sound was investigated by determining their ability to localize pure tones from 500 Hz to 32 kHz. In addition, their ability to use the binaural time cues present in the envelope of a signal was determined by presenting them with a 1-kHz tone that was amplitude modulated at either 250 or 500 Hz. Although the animals were easily able to localize tones above 2 kHz, indicating that they could use the binaural intensity difference cue, they were virtually unable to localize the lower-frequency stimuli, indicating that they could not use the binaural phase (time) cue. Although some animals showed a residual ability to localize low-frequency tones, co... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3322713 Mon, 22 Feb 2010 00:00:00 +0100 3322713 http://www.medworm.com/index.php?rid=3279808&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%3D20156543%26dopt%3DAbstract Authors: Bornitz M, Hardtke HJ, Zahnert T The extension of indication of implantable hearing aids to cases of conductive hearing loss pushed the development of these devices. There is now a great variety of devices available with different actuator concepts and different attachment points to the middle ear or inner ear fluid. But there is little comparative data available about the devices to provide an insight into advantages and disadvantages of different types of actuators and attachment points at the ossicular chain.This paper investigates two principle (idealized) types of actuators in respect of attachments points at the ossicular chain and direction of excitation. Other parts of implantable hearing aids like microphone, amplifier and signal processing electronics were not incorp... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3279808 Fri, 12 Feb 2010 00:00:00 +0100 3279808 http://www.medworm.com/index.php?rid=3273157&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%3D20149854%26dopt%3DAbstract Authors: van Dijk P, Mason MJ, Schoffelen RL, Narins PM, Meenderink SW The frog inner ear contains three regions that are sensitive to airborne sound and which are functionally distinct. (1) The responses of nerve fibres innervating the low-frequency, rostral part of the amphibian papilla (AP) are complex. Electrical tuning of hair cells presumably contributes to the frequency selectivity of these responses. (2) The caudal part of the AP covers the mid-frequency portion of the frog's auditory range. It shares the ability to generate both evoked and spontaneous otoacoustic emissions with the mammalian cochlea and other vertebrate ears. (3) The basilar papilla functions mainly as a single auditory filter. Its simple anatomy and function provide a model system for testing hypotheses conce... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3273157 Mon, 08 Feb 2010 00:00:00 +0100 3273157 http://www.medworm.com/index.php?rid=3273159&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%3D20146934%26dopt%3DAbstract In this study, we adapted a tissue indentation technique and inverse finite-element analysis to estimate the Young's modulus of the eardrum. A custom-built indentation apparatus was used to perform indentation testing on seven rat eardrums in situ after immobilizing the malleus. Testing was done in most cases on the posterior pars tensa. The unloaded shape of each eardrum was measured and used to construct finite-element models with subject-specific geometries to simulate the indentation experiment. The Young's modulus of each specimen was then estimated by numerically optimizing the Young's modulus of each model so that simulation results matched corresponding experimental data. R1-2: Using an estimated value of 12 mum for the thickness of each model eardrum, the estimated average Young's... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3273159 Sun, 07 Feb 2010 00:00:00 +0100 3273159 http://www.medworm.com/index.php?rid=3273158&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%3D20146935%26dopt%3DAbstract Authors: Stankovic KM, Adachi O, Tsuji K, Kristiansen AG, Adams JC, Rosen V, McKenna MJ Our long term goal is to understand the molecular pathology of otosclerosis and to develop better forms of therapy. Toward this goal, the current study focused on characterizing the molecular factors responsible for the unique biological features of the otic capsule: its minimal rate of remodeling, and lack of healing capacity when fractured. We compared expression levels of 62 genes involved in bone metabolism between the adult murine otic capsule and the tibia and parietal bones; the latter exemplify bones formed by endochondral and intramembranous ossification, respectively. Gene expression levels were measured using real-time quantitative RT-PCR and analyzed using tools of bioinformatics. Expres... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3273158 Sun, 07 Feb 2010 00:00:00 +0100 3273158 http://www.medworm.com/index.php?rid=3263297&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%3D20144699%26dopt%3DAbstract Authors: Drennan WR, Won JH, Nie K, Jameyson E, Rubinstein JT Experienced users of the Clarion cochlear implant were tested acutely with the HiResolution (HiRes) and HiRes Fidelity120 (F120) processing strategies. Three psychophysically-based tests were used including spectral-ripple discrimination, Schroeder-phase discrimination and temporal modulation detection. Three clinical outcome measures were used including consonant-nucleus-consonant (CNC) word recognition in quiet, word recognition in noise and the clinical assessment of music perception (CAMP). Listener's spectral-ripple discrimination ability improved with F120, but Schroeder-phase discrimination was worse with F120 than with HiRes. Listeners who had better than average acuity showed the biggest effects. There were no signi... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3263297 Fri, 05 Feb 2010 00:00:00 +0100 3263297 http://www.medworm.com/index.php?rid=3263296&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%3D20144700%26dopt%3DAbstract Authors: Hsieh IH, Saberi K Many natural sounds such as speech contain concurrent amplitude and frequency modulation (AM and FM), with the FM components often in the form of directional frequency sweeps or glides. Most studies of modulation coding, however, have employed one modulation type in stationary carriers, and in cases where mixed-modulation sounds have been used, the FM component has typically been confined to an extremely narrow range within a critical band. The current study examined the ability to detect AM signals carried by broad logarithmic frequency sweeps using a 2-alternative forced-choice adaptive psychophysical design. AM detection thresholds were measured as a function of signal modulation rate and carrier sweep frequency region. Thresholds for detection of AM in a... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3263296 Fri, 05 Feb 2010 00:00:00 +0100 3263296 http://www.medworm.com/index.php?rid=3263295&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%3D20144701%26dopt%3DAbstract We examined 'presbycusis phenotypes' in a database of 960 subjects (552 female, 408 male, 18 to 92 yrs) that each had 30 measures of peripheral hearing sensitivity: pure tone audiograms for left and right ears from 0.25 kHz to 8 kHz and DPOAE for each ear with F(mean) = 1 to 6.4 kHz. Surprisingly, the hearing phenotypes did not naturally separate into discrete classes of presbycusis. Principal component (PC) analysis revealed that two principal components account for 74% of the variance among the 30 measures of hearing. The two components represent the overall degree (PC1) and configuration of loss (Flat vs. Sloping; PC2) and the phenotypes form a continuum when plotted against them. A heuristic partitioning of this continuum produced classes of presbycusis that vary in their degree of Slo... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3263295 Fri, 05 Feb 2010 00:00:00 +0100 3263295 http://www.medworm.com/index.php?rid=3255408&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%3D20138978%26dopt%3DAbstract This study examined the effect of three primary acoustic features -frequency, intensity and spatial location-on auditory saccade characteristics in humans, and compared them to visual saccades. Saccade targets were presented from an azimuthal array of speakers and LEDs spanning +/-36 degrees . There was an 'eccentricity effect' for auditory saccades such that latencies decreased by up to 70 ms with eccentricity. This was observed for all frequencies and intensities tested. There was a smaller effect in the opposite direction effect for visual saccades. Auditory saccades had similar latencies to visual saccades (within 5 ms) for near midline locations, but were up to 90 ms faster at eccentric locations (+/-36 degrees ). Overall, saccadic latencies were shortest for wideband noise and narrow... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3255408 Thu, 04 Feb 2010 00:00:00 +0100 3255408 http://www.medworm.com/index.php?rid=3238078&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%3D20123119%26dopt%3DAbstract This study aims to accurately describe the ERB of primary-like and chopper units in the ventral cochlear nucleus, the first brainstem processing station of the central auditory system. Recordings were made from 1,020 isolated single-units in the ventral cochlear nucleus of anesthetized guinea pigs in response to pure tone stimuli which varied in frequency and in sound level. Frequency-threshold tuning curves were constructed for each unit and estimates of the ERB determined using methods previously described for auditory-nerve-fibre data in the same species. Primary-like, primary-notch, and sustained- and transient-chopper units showed frequency-selectivity almost identical to that recorded in the auditory nerve. Their tuning at pure-tone threshold can be described as a function of best fr... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238078 Sat, 30 Jan 2010 00:00:00 +0100 3238078 http://www.medworm.com/index.php?rid=3238077&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%3D20123120%26dopt%3DAbstract Authors: Pratt H, Starr A, Michalewski HJ, Dimitrijevic A, Bleich N, Mittelman N The purpose of this study was to compare cortical brain responses evoked by amplitude modulated acoustic beats of 3 and 6 Hz in tones of 250 and 1000 Hz with those evoked by their binaural beats counterparts in unmodulated tones to indicate whether the cortical processes involved differ. Event-Related Potentials (ERPs) were recorded to 3- and 6-Hz acoustic and binaural beats in 2,000 ms duration 250- and 1000 Hz tones presented with approximately 1 s intervals. Latency, amplitude and source current density estimates of ERP components to beats-evoked oscillations were determined and compared across beat types, beat frequencies and base (carrier) frequencies. All stimuli evoked tone-onset components followed... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238077 Sat, 30 Jan 2010 00:00:00 +0100 3238077 http://www.medworm.com/index.php?rid=3238076&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%3D20123121%26dopt%3DAbstract Authors: Eggermont JJ The spectrotemporal receptive field (STRF) is frequently used to characterize the linear frequency-time filter properties of the auditory system up to the neuron recorded from. STRFs are extremely stimulus dependent, reflecting the strong non-linearities in the auditory system. Changes in the STRF with stimulus type (tonal, noise-like, vocalizations), sound level and spectro-temporal sound density are reviewed here. Effects on STRF shape of task and attention are also briefly reviewed. Models to account for these changes, potential improvements to STRF analysis, and implications for neural coding are discussed. PMID: 20123121 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238076 Sat, 30 Jan 2010 00:00:00 +0100 3238076 http://www.medworm.com/index.php?rid=3238089&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%3D20123055%26dopt%3DAbstract Authors: Santos-Sacchi J . PMID: 20123055 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238089 Fri, 29 Jan 2010 00:00:00 +0100 3238089 http://www.medworm.com/index.php?rid=3238088&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%3D20123056%26dopt%3DAbstract Authors: Dallos P A brief overview of some of the controversies surrounding cochlear amplification is presented. It is noted that speed limitation is not a strong argument against somatic motility being the amplifier. It further appears that due to the presence of adaptation, somatic motility is unlikely to control the operating-point of a ciliary amplifier. While both putative mechanisms are likely to operate, somatic motility dominates amplification in the mammal. PMID: 20123056 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238088 Fri, 29 Jan 2010 00:00:00 +0100 3238088 http://www.medworm.com/index.php?rid=3238087&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%3D20123057%26dopt%3DAbstract Authors: Meaud J, Grosh K In most models of the mammalian cochlea, either mathematical or conceptual, the sensitivity of the BM to low level acoustic stimulus is explained by the presence of outer hair cell (OHC) somatic motility. However, recent experimental evidence indicates that OHC hair bundle (HB) motility can operate with submillisecond time constants. In this paper, we implement a simple phenomenological mathematical model of HB motility, based on the ansatz that HB forcing adds mechanical energy to the system. Our preliminary predictions using models that combine HB and somatic OHC motility indicate that HB motility is not necessary for cochlear amplification while OHC somatic motility is necessary. However we show how HB motility could work in synergy with OHC somatic motilit... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238087 Fri, 29 Jan 2010 00:00:00 +0100 3238087 http://www.medworm.com/index.php?rid=3238086&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%3D20123058%26dopt%3DAbstract Authors: Fettiplace R, Hackney C . PMID: 20123058 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238086 Fri, 29 Jan 2010 00:00:00 +0100 3238086 http://www.medworm.com/index.php?rid=3238085&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%3D20123059%26dopt%3DAbstract Authors: Dierkes K, Lindner B, Jülicher F . PMID: 20123059 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238085 Fri, 29 Jan 2010 00:00:00 +0100 3238085 http://www.medworm.com/index.php?rid=3238084&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%3D20123060%26dopt%3DAbstract Authors: Martin P, Hudspeth AJ One may investigate the basis of the active process in either of two ways. Most studies have focused on the subcellular and molecular details of the candidate mechanisms, membrane-based electromotility and active hair-bundle motility. Despite the present uncertainties in the field, such detailed mechanistic investigations must ultimately reveal the origins of the four cardinal aspects of the active process: amplification, frequency tuning, compressive nonlinearity, and spontaneous otoacoustic emission. A second approach is to inquire, not about mechanistic details, but instead about the principles underlying the active process. What feature of the active process accounts for the unusual phenomena associated with hearing? What is the connection between the... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238084 Fri, 29 Jan 2010 00:00:00 +0100 3238084 http://www.medworm.com/index.php?rid=3238083&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%3D20123061%26dopt%3DAbstract Authors: Brownell WE Acoustic vibrations enter and neuronal action potentials leave the inner ear. An interplay of mechanical and electrical energy results in hair cell receptor potentials that ultimately trigger neurotransmitter release at the afferent synapse. The diffusion of neurotransmitter across the synaptic cleft depolarizes 8th nerve terminals and initiates action potentials that travel to the central nervous system. The action potentials encode information about the spectral and temporal content of environmental sounds. The ability to localize predator or prey is improved by analyzing sounds over a wide range of frequencies resulting in an evolutionary selection pressure for detecting ever higher frequencies. Nature has incorporated diverse strategies to overcome physical con... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238083 Fri, 29 Jan 2010 00:00:00 +0100 3238083 http://www.medworm.com/index.php?rid=3238080&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%3D20123062%26dopt%3DAbstract Authors: Avan P, Petit C . PMID: 20123062 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238080 Fri, 29 Jan 2010 00:00:00 +0100 3238080 http://www.medworm.com/index.php?rid=3238079&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%3D20123063%26dopt%3DAbstract Authors: Ashmore J . PMID: 20123063 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3238079 Fri, 29 Jan 2010 00:00:00 +0100 3238079 http://www.medworm.com/index.php?rid=3231901&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%3D20116419%26dopt%3DAbstract Authors: Perkins R, Fay JP, Rucker P, Rosen M, Olson L, Puria S The hypothesis is tested that an open-canal hearing device, with a microphone in the ear canal, can be designed to provide amplification over a wide bandwidth and without acoustic feedback. In the design under consideration, a transducer consisting of a thin silicone platform with an embedded magnet is placed directly on the tympanic membrane. Sound picked up by a microphone in the ear canal, including sound-localization cues thought to be useful for speech perception in noisy environments, is processed and amplified, and then used to drive a coil near the tympanic-membrane transducer. The perception of sound results from the vibration of the transducer in response the electromagnetic field produced by the coil. Sixteen su... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3231901 Wed, 27 Jan 2010 00:00:00 +0100 3231901 http://www.medworm.com/index.php?rid=3231900&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%3D20116420%26dopt%3DAbstract Authors: Gleich O, Langemann U The basilar papilla length increases systematically with body mass for 41 species from more than 10 avian orders and this relation does not differ between phylogenetic groups. Audiograms of 25 non-strigiform and 12 owl species, normalized relative to best frequency and best threshold, were used to compare audiogram shapes. The analysis revealed that the high frequency flank of the audiogram was remarkably similar across non-strigiform species. The high frequency limit was on average 1.1 octaves above the best frequency, the low frequency flank was less steep and showed much more species dependent variability. Audiogram shape in owls was much more variable. Morphological gradients along the basilar papilla revealed a small species dependent variability for... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3231900 Wed, 27 Jan 2010 00:00:00 +0100 3231900 http://www.medworm.com/index.php?rid=3231899&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%3D20116421%26dopt%3DAbstract This article begins with an overview of the principal circuits and how each is related to information flow along major axes of the network. The discussion then turns to a description of neurochemical gradients along these axes, highlighting recent work on glutamate transporters in the thalamocortical projections to auditory cortex. The article concludes with a brief discussion of relevant neurophysiological findings as they relate to structural gradients in the network. PMID: 20116421 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3231899 Wed, 27 Jan 2010 00:00:00 +0100 3231899 http://www.medworm.com/index.php?rid=3231898&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%3D20116422%26dopt%3DAbstract Authors: Huetz C, Gourévitch B, Edeline JM Over the last 15 years, an increasing number of studies have described the responsiveness of thalamic and cortical neurons to communication sounds. Whereas initial studies have simply looked for neurons exhibiting higher firing rate to conspecific vocalizations over their modified, artificially synthesized versions, more recent studies determine the relative contribution of "rate coding" and "temporal coding" to the information transmitted by spike trains. In this article, we aim at reviewing the different strategies employed by thalamic and cortical neurons to encode information about acoustic stimuli, from artificial to natural sounds. Considering data obtained with simple stimuli, we first illustrate that different facets of temporal c... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3231898 Wed, 27 Jan 2010 00:00:00 +0100 3231898 http://www.medworm.com/index.php?rid=3213213&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%3D20100558%26dopt%3DAbstract CONCLUSIONS: : We have developed an intuitive, rapid, and effective means of exploring otological micro-CT datasets. This system may provide a foundation for additional work based on middle-ear anatomical data. PMID: 20100558 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3213213 Fri, 22 Jan 2010 00:00:00 +0100 3213213 http://www.medworm.com/index.php?rid=3213214&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%3D20097279%26dopt%3DAbstract Authors: Edds-Walton PL, Holstein GR, Fay RR Binaural computations involving the convergence of excitatory and inhibitory inputs have been proposed to explain directional sharpening and frequency tuning documented in the brainstem of a teleost fish, the oyster toadfish (Opsanus tau). To assess the presence of inhibitory neurons in the ascending auditory circuit, we used a monoclonal antibody to GABA to evaluate immunoreactivity at three levels of the circuit: the first order descending octaval nucleus (DON), the secondary octaval population (dorsal division), and the midbrain torus semicircularis. We observed a subset of immunoreactive (IR) cells and puncta distributed throughout the neuropil at all three locations. To assess whether contralateral inhibition is present, fluorescent dex... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3213214 Thu, 21 Jan 2010 00:00:00 +0100 3213214 http://www.medworm.com/index.php?rid=3201191&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%3D20093174%26dopt%3DAbstract Authors: Macdonald EN, Pichora-Fuller MK, Schneider BA In a previous study, we demonstrated that word recognition performance was reduced when the low-frequency components of speech (0-1.2 kHz) were distorted by temporal jittering, but not when they were distorted by spectral smearing (Pichora-Fuller et al., 2007). Temporal jittering distorts the fine structure of the speech signal with negligible alteration of either its long-term spectral or amplitude envelope characteristics. Spectral smearing simulates the effects of broadened auditory filters that occur with cochlear hearing loss (Baer and Moore, 1993). In the present study, the high-frequency components of speech (1.2-7 kHz) were distorted with jittering and smearing. Word recognition in noise for both distortion conditions was p... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3201191 Mon, 18 Jan 2010 00:00:00 +0100 3201191 http://www.medworm.com/index.php?rid=3188877&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%3D20079820%26dopt%3DAbstract Authors: Fowler CG, Chiasson KB, Leslie TH, Thomas D, Beasley TM, Kemnitz JW, Weindruch R Caloric restriction (CR) slows aging in many species and protects some animals from age-related hearing loss (ARHL), but the effect on humans is not yet known. Because rhesus monkeys are long-lived primates that are phylogenically closer to humans than other research animals are, they provide a better model for studying the effects of CR in aging and ARHL. Subjects were from the pool of 55 rhesus monkeys aged 15-28 years who had been in the Wisconsin study on CR and aging for 8-13.5 years. Distortion product otoacoustic emissions (DPOAE) with f2 frequencies from 2211-8837 Hz and auditory brainstem response (ABR) thresholds from clicks and 8, 16, and 32 kHz tone bursts were obtained. DPOAE levels d... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3188877 Wed, 13 Jan 2010 00:00:00 +0100 3188877 http://www.medworm.com/index.php?rid=3179230&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%3D20074632%26dopt%3DAbstract Authors: Nakamagoe M, Tabuchi K, Uemaetomari I, Nishimura B, Hara A Gentamicin induces outer hair cell death through the apoptotic pathway. It has been reported that this death pathway of outer hair cells is mediated by specific apoptotic enzymes including c-jun N-terminal kinase (JNK) and caspases. 17beta-Estradiol (E2), the most potent estrogen, is known to function as an antiapoptotic agent to prevent the death of various cell types. The purpose of the present study was to examine the effects of E2 on gentamicin-induced apoptotic cell death in outer hair cells. The basal turn organ of Corti explants from p3 or p4 rats were maintained in a tissue culture and exposed to 100 muM gentamicin for 48 hours. The effects of E2 on gentamicin-induced outer hair cell loss, JNK activation, and s... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3179230 Mon, 11 Jan 2010 00:00:00 +0100 3179230 http://www.medworm.com/index.php?rid=3164577&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%3D20060461%26dopt%3DAbstract Authors: Willott JF, Vandenbosche J, Shimizu T Neurons in the anteroventral cochlear nucleus (AVCN) of DBA/2J (D2) and C57BL/6J (B6) mice were immunohistochemically labeled for the calcium binding protein parvalbumin (PV). Prior to this, mice were treated for 12h nightly with a "high-frequency" augmented acoustic environment (HAAE: repetitive bursts of a 70dB sound pressure level, half-octave noise band centered at 20kHz). This was done during the period that hearing loss occurs: pre-weaning to 55days in D2 mice and weaning to 9months in B6 mice. After HAAE treatment in D2 mice, high-frequency hearing loss was ameliorated and fewer PV-labeled neurons were found in the AVCN compared to untreated controls. HAAE treatment in B6 mice exacerbated high-frequency hearing loss, yet the number ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3164577 Fri, 08 Jan 2010 00:00:00 +0100 3164577 http://www.medworm.com/index.php?rid=3164576&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%3D20060883%26dopt%3DAbstract Authors: Ashmore J, Avan P, Brownell WE, Dallos P, Dierkes K, Hackney C, Lindner B, Jülicher F, Fettiplace R, Grosh J, Hudspeth AJ, Martin P, Meaud J, Petit C, Santos Sacchi JR, Canlon B This publication is intended to give the experts in the field of cochlear mechanics an opportunity to voice their personal opinion on the one mechanism they believe dominates cochlear amplification in mammals. A collection of these ideas are presented here for the auditory community and others interested in the cochlear amplifier. Each expert has given their own personal view on the topic and at the end of their commentary they have suggested several experiments that would be required for the decisive mechanism underlying the cochlear amplifier. These experiments are presently lacking but if succe... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3164576 Thu, 07 Jan 2010 00:00:00 +0100 3164576 http://www.medworm.com/index.php?rid=3164575&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%3D20060884%26dopt%3DAbstract Authors: Kimitsuki T, Komune N, Noda T, Takaiwa K, Ohashi M, Komune S One of the potassium currents, I(K,n), is already activated at the resting potential of the cell and thus determines the membrane potential. KCNQ4 channel has been identified as the molecular correlate of I(K,n). In the present study, we measured I(K, n) in acutely isolated IHCs of guinea-pig cochlea using the whole-cell voltage-clamp techniques, and investigated the properties of the currents. I(K, n) was 70% activated around the resting potential of -60 mV and deactivated on hyperpolarization. I(K, n) was blocked by the KCNQ-channel blockers, linopirdine (100 muM) and XE991 (10 muM), but was insensitive to both I(K,f) blocker, tetraethylammonium (TEA), and I(K,s) blocker, 4-aminopyridine (4-AP). There was no signif... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3164575 Thu, 07 Jan 2010 00:00:00 +0100 3164575 http://www.medworm.com/index.php?rid=3164578&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%3D20060460%26dopt%3DAbstract Authors: Van Trump WJ, Coombs S, Duncan K, McHenry MJ Hair cells of the lateral line system in fish may differ in their susceptibility to damage by aminoglycoside antibiotics. Gentamicin has been reported to damage hair cells within canal neuromasts, but not those within superficial neuromasts. This finding, based on SEM imaging, indicates a distinction in the physiology of hair cells between the two classes of neuromast. Studies concerned with the individual roles of canal and superficial neuromasts in behavior have taken advantage of this effect in an attempt to selectively disable canal neuromasts without affecting superficial neuromast function. Here we present an experimental test of the hypothesis that canal neuromasts are more vulnerable to gentamicin than superficial neuromasts... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3164578 Wed, 06 Jan 2010 00:00:00 +0100 3164578 http://www.medworm.com/index.php?rid=3154038&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%3D20056140%26dopt%3DAbstract Authors: Elgoyhen AB, Franchini LF The hair cells of the vertebrate inner ear posses active mechanical processes to amplify their inputs. The stereocilia bundle of various vertebrate animals can produce active movements. Though standard stereocilia-based mechanisms to promote amplification persist in mammals, an additional radically different mechanism evolved: the so called somatic electromotility which refers to the elongation/contraction of the outer hair cells' (OHC) cylindrical cell body in response to membrane voltage changes. Somatic electromotility in OHCs, as the basis for cochlear amplification, is a mammalian novelty and it is largely dependent upon the properties of the unique motor protein prestin. We review recent literature which has demonstrated that although the gene e... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3154038 Mon, 04 Jan 2010 00:00:00 +0100 3154038 http://www.medworm.com/index.php?rid=3142998&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%3D20045046%26dopt%3DAbstract This study investigated the change in cochlear function by measurement of endocochlear potential (EP) and potassium concentration ([K(+)]) caused by vestibular labyrinth destruction in the acute phase. Hartley guinea pigs underwent lateral semicircular canal (LSCC) transection with suctioning of the perilymph, ampullectomy, or destruction of the LSCC, superior SCC, and lateral part of the vestibule. The EP and [K(+)] were monitored using double-barreled ion-selective microelectrodes in the second turn of cochlea. The EP showed little to mild change after LSCC transectioning or ampullectomy, but declined variously and drastically after vestibulotomy. The EP did not recover but [K(+)] partially recovered after vestibulotomy. Disturbance of the mechanism of cochlear function caused by vestibu... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3142998 Tue, 29 Dec 2009 00:00:00 +0100 3142998 http://www.medworm.com/index.php?rid=3130199&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%3D20036723%26dopt%3DAbstract Authors: Pienkowski M, Eggermont JJ Long-term, passive, continuous exposure of mature animals to moderate-level, band-limited sounds can profoundly decrease neural activity in primary auditory cortex (AI) to sounds in the exposure frequency range, and increase activity to sounds outside the exposure range. The resulting reorganization of the AI tonotopic map resembles that following a restricted lesion of the cochlear epithelium. Here we show qualitatively similar effects of passive exposure when it is limited to 12 h/day, simulating a noisy-work/quiet-living environment, albeit at substantially lower intensity levels (68 dB SPL) than are considered harmful to hearing. Compared to continuous exposure at the same SPL and over a similar duration (6-12 weeks), this intermittent exposure p... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3130199 Thu, 24 Dec 2009 00:00:00 +0100 3130199 http://www.medworm.com/index.php?rid=3122691&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%3D20034549%26dopt%3DAbstract Authors: Cheng JT, Aarnisalo AA, Harrington E, Hernandez-Montes MD, Furlong C, Merchant SN, Rosowski JJ Sound-induced motion of the surface of the human tympanic membrane (TM) was studied by stroboscopic holographic interferometery, which measures the amplitude and phase of the displacement at each of about 40000 points on the surface of the TM. Measurements were made with tonal stimuli of 0.5, 1, 4 and 8 kHz. The magnitude and phase of the sinusoidal displacement of the TM at each driven frequency were derived from the fundamental Fourier component of the raw displacement data computed from stroboscopic holograms of the TM recorded at eight stimulus phases. The correlation between the Fourier estimates and measured motion data was generally above 0.9 over the entire TM surface. We use... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3122691 Mon, 21 Dec 2009 00:00:00 +0100 3122691 http://www.medworm.com/index.php?rid=3122690&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%3D20034550%26dopt%3DAbstract Authors: Popper AN, Fay RR In this paper we reconsider the designation of fishes as being either "hearing specialists" or "hearing generalists," and recommend dropping the terms. We argue that this classification is only vaguely and variously defined in the literature, and that these terms often have unclear and different meaning to different investigators. Furthermore, we make the argument that the ancestral, and most common, mode of hearing in fishes involves sensitivity to acoustic particle motion via direct inertial stimulation of the otolith organ(s). Moreover, any possible pressure sensitivity is the result of the presence of an air bubble (e.g., the swim bladder), and that hearing sensitivity may be enhanced by the fish having a specific connection between the inner ear to a bub... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3122690 Mon, 21 Dec 2009 00:00:00 +0100 3122690 http://www.medworm.com/index.php?rid=3115517&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%3D20026266%26dopt%3DAbstract Authors: Aerts JR, Dirckx JJ It is generally accepted that the middle ear acts mainly as a linear system for sound pressures up to 130 dB SPL in the auditory frequency range. However, at quasi-static pressure loads a strong nonlinear response has been demonstrated. Consequently, small nonlinear distortions may also be present in the middle ear response in the auditory frequency range. A new measurement method was developed to quickly determine vibration response, nonlinear distortions and noise level of acoustically driven biomechanical systems. Specially designed multisines are used for the excitation of the test system. The method is applied on a gerbil eardrum for sound pressures ranging from 90 to 120 dB SPL and for frequencies ranging from 125 Hz to 16 kHz. The experiments show th... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3115517 Thu, 17 Dec 2009 00:00:00 +0100 3115517 http://www.medworm.com/index.php?rid=3105650&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%3D20018234%26dopt%3DAbstract Authors: Strait DL, Kraus N, Parbery-Clark A, Ashley R A growing body of research suggests that cognitive functions, such as attention and memory, drive sensory perception by tuning sensory mechanisms to relevant acoustic features. Long term musical experience is also known to modulate lower-level auditory function, although the mechanisms by which this occurs remain uncertain. In order to tease apart the mechanisms that drive perceptual enhancements in musicians, we posed the question: do well-developed cognitive abilities fine-tune auditory perception in a top-down fashion? We administered a standardized battery of perceptual and cognitive tests to adult musicians and non-musicians, including tasks either more or less susceptible to cognitive control (e.g., backward versus simultaneo... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3105650 Mon, 14 Dec 2009 00:00:00 +0100 3105650 http://www.medworm.com/index.php?rid=3076011&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%3D19995597%26dopt%3DAbstract This study was undertaken to determine if adenosine signalling pathways are involved in protection against noise injury. A(1) adenosine receptor expression levels were altered in the cochlea exposed to loud sound, suggesting their involvement in the development of noise injury. Adenosine and selective adenosine receptor agonists (CCPA, CGS-21680 and Cl-IB-MECA) were applied to the round window membrane of the cochlea six hours after noise exposure. Auditory brainstem responses measured 48 hours after drug administration demonstrated partial recovery of hearing thresholds (up to 20 dB) in the cochleae treated with adenosine (non-selective adenosine receptor agonist) or CCPA (selective A(1) adenosine receptor agonist). In contrast, the selective A(2A) adenosine receptor agonist CGS-21680 and... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3076011 Sat, 05 Dec 2009 00:00:00 +0100 3076011 http://www.medworm.com/index.php?rid=3076012&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%3D19969056%26dopt%3DAbstract Authors: Offergeld C, Kromeier J, Merchant SN, Lasurashvili N, Neudert M, Bornitz M, Laszig R, Zahnert T A large air-bone-gap after ossiculoplasty may be due to a malpositioned or displaced prosthesis. Rotational Tomography (RT) has the potential to provide high-resolution images of implants without artifacts and with less radiation dosage than CT scan. Twenty-seven temporal bone specimens underwent measurements of middle ear transfer function using Laser-Doppler-Vibrometry (LDV) before and after placement of ossicular replacement prostheses (PORPs, TORPs) made of titanium. RT was performed on all specimens. RT allowed 3-dimensional viewing of the temporal bone, accurate localization of implants within the reconstructed middle ear and determination of angles between the inserted prosth... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3076012 Fri, 04 Dec 2009 00:00:00 +0100 3076012 http://www.medworm.com/index.php?rid=3067661&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%3D19963053%26dopt%3DAbstract This study aimed to assess whether or not temporal envelope (E) and fine structure (TFS) cues in speech convey distinct phonetic information. Syllables uttered by a male and female speaker were (i) processed to retain either E or TFS within 16 frequency bands, (ii) lowpass or highpass filtered at different cutoff frequencies, and (iii) presented for identification to seven listeners. Psychometric functions were fitted using a sigmoid function, and used to determine crossover frequencies (cutoff frequencies at which lowpass and highpass filtering yielded equivalent performance), and gradients at each point of the psychometric functions (change in performance with respect to cutoff frequency). Crossover frequencies and gradients were not significantly different across speakers. Crossover fre... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3067661 Thu, 03 Dec 2009 00:00:00 +0100 3067661 http://www.medworm.com/index.php?rid=3067660&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%3D19963054%26dopt%3DAbstract Authors: Slee SJ, Young ED The most important acoustic cues available to the brain for sound localization are produced by the interaction of sound with the animal's head and external ears. As a first step in understanding the relation between these cues and their neural representation in a vocal new-world primate, we measured head related transfer functions (HRTFs) across frequency for a wide range of sound locations in three anesthetized marmoset monkeys. The HRTF magnitude spectrum has a broad resonance peak at 6-12 kHz that coincides with the frequency range of the major call types of this species. A prominent first spectral notch (FN) in the HRTF magnitude above this resonance was observed at most source locations. The center frequency of the FN increased monotonically from approxi... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3067660 Thu, 03 Dec 2009 00:00:00 +0100 3067660 http://www.medworm.com/index.php?rid=3034080&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%3D19932881%26dopt%3DAbstract Authors: Hackett TA, Schroeder CE PMID: 19932881 [PubMed - in process] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=3034080 Fri, 27 Nov 2009 21:40:05 +0100 3034080 http://www.medworm.com/index.php?rid=3034081&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%3D19931608%26dopt%3DAbstract Authors: Fitzgibbons PJ, Gordon-Salant S The study measured listener sensitivity to increments of a target inter-onset interval (IOI) embedded within isochronous tone sequences that featured a single accented tonal component. The sequences consisted of six 1000-Hz tone bursts separated by silent intervals to establish equal tonal IOIs of 200 ms within the sequence. Tone burst durations within the sequences were 50 ms, except one tone had a longer duration of 100 ms to produce a perception of accent. Duration DLs in ms for increments of a single sequence IOI were measured adaptively by adjusting the duration of the silent interval between two tones. Sequence position of the target IOI differed across conditions. Listeners included young normal-hearing adults and older adults with and wi... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3034081 Wed, 18 Nov 2009 00:00:00 +0100 3034081 http://www.medworm.com/index.php?rid=3009246&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%3D19922784%26dopt%3DAbstract Authors: Başkent D, Eiler CL, Edwards B The auditory system is capable of perceptually restoring inaudible portions of speech. This restoration may be compromised as a result of hearing impairment, particularly if it is combined with advanced age, because of degradations in the bottom-up and top-down processes. To test this hypothesis, phonemic restoration was quantitatively measured with hearing-impaired listeners of varying ages and degrees of hearing impairment, as well as with a normal-hearing control group. The results showed that the restoration benefit was negatively correlated with both hearing impairment and age, supporting the original hypothesis. Group data showed that listeners with mild hearing loss were able to perceptually restore the missing speech segments as wel... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3009246 Fri, 13 Nov 2009 00:00:00 +0100 3009246 http://www.medworm.com/index.php?rid=3002465&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%3D19913606%26dopt%3DAbstract Authors: Ohlemiller KK, Rosen AD, Gagnon PM We recently demonstrated a striking difference among inbred mouse strains in the effects of a single noise exposure, whereby CBA/J and CBA/CaJ (CBA) mice show moderate reversible reduction in the endocochlear potential (EP) while C57BL/6J (B6) mice do not (Ohlemiller, K.K., Gagnon, P.M. 2007. Genetic dependence of cochlear cells and structures injured by noise. Hearing Res. 224, 34-50). Acute EP reduction in CBA was reliably associated with characteristic pathology of the spiral ligament and stria vascularis, both immediately after noise and 8 weeks later. Analysis of B6xCBA F1 hybrid mice indicated that EP reduction and its anatomic correlates are co-inherited in an autosomal dominant manner. Further analysis of N2 mice resulting from the ba... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3002465 Wed, 11 Nov 2009 00:00:00 +0100 3002465 http://www.medworm.com/index.php?rid=3002469&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%3D19909802%26dopt%3DAbstract Authors: Seeber BU, Kerber S, Hafter ER The article reports the experience gained from two implementations of the "Simulated Open-Field Environment" (SOFE), a setup that allows sounds to be played at calibrated levels over a wide frequency range from multiple loudspeakers in an anechoic chamber. Playing sounds from loudspeakers in the free-field has the advantage that each participant listens with their own ears, and individual characteristics of the ears are captured in the sound they hear. This makes an easy and accurate comparison between various listeners with and without hearing devices possible. The SOFE uses custom calibration software to assure individual equalization of each loudspeaker. Room simulation software creates the spatio-temporal reflection pattern of sound sources i... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3002469 Mon, 09 Nov 2009 00:00:00 +0100 3002469 http://www.medworm.com/index.php?rid=3002468&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%3D19909803%26dopt%3DAbstract Authors: Aarnisalo AA, Cheng JT, Ravicz ME, Furlong C, Merchant SN, Rosowski JJ Stroboscopic holography was used to quantify dynamic deformations of the tympanic membrane (TM) of the entire surface of the TM before and after cartilage tympanoplasty of the posterior or posterior-superior part of the TM. Cartilage is widely used in tympanoplasties to provide mechanical stability for the TM. Three human cadaveric temporal bones were used. A 6 mm x 3 mm oval cartilage graft was placed through the widely opened facial recess onto the medial surface of the posterior or posterior-superior part of the TM. The graft was either in contact with the bony tympanic rim and manubrium or not. Graft thickness was either 0.5 or 1.0 mm. Stroboscopic holography produced displacement amplitude and phase ma... Hearing Research journals http://www.medworm.com/rss/comments.php?id=3002468 Mon, 09 Nov 2009 00:00:00 +0100 3002468 http://www.medworm.com/index.php?rid=2985535&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%3D19903514%26dopt%3DAbstract Authors: Syka J Due to the rising number of the aged human population all over the world, presbycusis is a phenomenon that deserves the increasing attention of the medical community as regards to prevention and treatment. This requires finding appropriate animal models for human presbycusis that will be useful in future experiments. Among the available rat strains, the Fischer 344 (F344) strain promises to serve as a model producing prompt and profound presbycusis. Hearing thresholds begin to increase in this strain within the first year of life, toward the end of the second year the thresholds are very high. The threshold shifts progress in both ears independently. The rapid deterioration of distortion product otoacoustic emissions, with the majority of outer hair cells (OHC) being pr... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2985535 Sat, 07 Nov 2009 00:00:00 +0100 2985535 http://www.medworm.com/index.php?rid=2985537&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%3D19900525%26dopt%3DAbstract Authors: Zhang PX, Hartmann WM In order to determine whether a sound source is in front or in back, listeners can use location-dependent spectral cues caused by diffraction from their anatomy. This capability was studied using a precise virtual-reality technique (VRX) based on a transaural technology. Presented with a virtual baseline simulation accurate up to 16 kHz, listeners could not distinguish between the simulation and a real source. Experiments requiring listeners to discriminate between front and back locations were performed using controlled modifications of the baseline simulation to test hypotheses about the important spectral cues. The experiments concluded: (1) Front/back cues were not confined to any particular 1/3rd or 2/3rd octave frequency region. Often adequate cues ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2985537 Fri, 06 Nov 2009 00:00:00 +0100 2985537 http://www.medworm.com/index.php?rid=2985536&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%3D19900526%26dopt%3DAbstract Authors: Popelka GR, Telukuntla G, Puria S Auditory thresholds with standardized clinical procedures are obtained over a much nar- rower frequency range by bone conduction than by air conduction. As a result, diagnostic information for both sensorineural and conductive-mechanism function is incomplete for high frequencies. A new magnetostrictive bone-conduction transducer that has the poten- tial for improved output in the high-frequency range was evaluated in the laboratory and in a variety of subjects with normal hearing (N=11) or sensorineural hearing loss (N=9). La- boratory results indicated that harmonic distortion and acoustic radiation were both suffi- ciently low to allow accurate threshold measurements. Auditory thresholds obtained with this magnetostrictive bone-conduction t... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2985536 Fri, 06 Nov 2009 00:00:00 +0100 2985536 http://www.medworm.com/index.php?rid=2955057&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%3D19878711%26dopt%3DAbstract This study evaluated the effects of various concentrations of the volatile anesthetic isoflurane (1 - 3%) on the compound action potential (CAP), cochlear microphonic (CM) and auditory brainstem response (ABR). Recordings were initiated in the awake, lightly restrained animal. Anesthesia was induced with a single dose of Hypnorm((R)) (fentanyl and fluanisone). After tracheostomy increasing isoflurane concentrations were applied in N(2)O/O(2) via controlled ventilation. Data were compared to recordings in the awake animal using repeated measures ANOVA and Dunnett's post hoc test. On average, isoflurane dose-dependently suppressed the amplitude and increased the latency of the CAP. CM amplitude was suppressed. These effects were most profound at high frequencies and were typically significan... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2955057 Tue, 27 Oct 2009 00:00:00 +0100 2955057 http://www.medworm.com/index.php?rid=2955056&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%3D19878712%26dopt%3DAbstract Authors: Friesen LM, Picton TW When cortical auditory evoked potentials (CAEPs) are recorded in individuals with a cochlear implant (CI), electrical artifact can make the CAEP difficult or impossible to measure. Since increasing the interstimulus interval (ISI) increases the amplitude of physiological responses without changing the artifact, subtracting CAEPs recorded with a short ISI from those recorded with a longer ISI should show the physiological response without any artifact. In the first experiment, N1-P2 responses were recorded using a speech syllable and tone, paired with ISIs that changed randomly between 0.5 and 4 seconds. In the second experiment, the same stimuli, at ISIs of either 500 or 3000 ms, were presented in blocks that were homogeneous or random with respect to the... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2955056 Tue, 27 Oct 2009 00:00:00 +0100 2955056 http://www.medworm.com/index.php?rid=2955055&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%3D19878713%26dopt%3DAbstract Authors: de La Rochefoucauld O, Olson ES Based on comparisons of ear canal and scala vestibuli pressures the gerbil middle ear transmits sound with a gain of approximately 25 dB that is almost flat from 2 to 40 kHz, and with a delay-like phase corresponding to a 25 - 30 mus delay. How the middle ear is able to transmit sound with such high temporal and amplitude fidelity is not known, and is particularly mysterious given the complex motion the ossicles and tympanic membrane (TM) are known to undergo. To explore this question, we looked at the velocities of the manubrium and along a line on the TM. The TM motion was complex, and could be approximated as the combination of a wave-like motion and an in-and-out piston-like motion. The manubrium underwent bending at some stimulus frequencie... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2955055 Tue, 27 Oct 2009 00:00:00 +0100 2955055 http://www.medworm.com/index.php?rid=2955054&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%3D19878714%26dopt%3DAbstract Authors: Puria S, Steele C The development of the unique capacity for high frequency hearing in many mammals was due in part to changes in the middle ear, such as the evolution of three distinct middle ear bones and distinct radial and circumferential collagen fiber layers in the eardrum. Ossicular moment(s) of inertia (MOI) and principal rotational axes, as well as eardrum surface areas, were calculated from micro-CT-based 3-D reconstructions of human, cat, chinchilla, and guinea pig temporal bones. For guinea pig and chinchilla, the fused malleus-incus complex rotates about an anterior-posterior axis, due to the relatively lightweight ossicles and bilateral symmetry of the eardrum. For human and cat, however, the MOI calculated for the unfused malleus are 5-6 times smaller for rotati... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2955054 Tue, 27 Oct 2009 00:00:00 +0100 2955054 http://www.medworm.com/index.php?rid=2935696&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%3D19857561%26dopt%3DAbstract Authors: Kumar G, Chokshi M, Richter CP In individuals with severe-to-profound hearing loss, cochlear implants (CIs) bypass normal inner ear function by applying electrical current directly into the cochlea, thereby stimulating surviving auditory nerve fibers. Although cochlear implants are able to restore some auditory sensation, they are far from providing normal hearing. It has been estimated that up to 75% of the current injected via a CI is shunted along scala tympani and is not available to stimulate auditory neurons. The path of the injected current and the consequent population of stimulated spiral ganglion cells are dependent upon the positions of the electrode contacts within the cochlea and the impedances of cochlear structures. However, characterization of the current path ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2935696 Fri, 23 Oct 2009 00:00:00 +0100 2935696 http://www.medworm.com/index.php?rid=2935695&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%3D19857562%26dopt%3DAbstract Authors: Okazaki S, Kanoh S, Tsukada M, Oka K Mismatch negativity (MMN) is a negative component of event-related brain potentials elicited by stimulus transitions. Stimulus duration transition also elicits MMN (duration MMN), with a magnitude that is related to the degree of duration change and the discrimination ability. The neural substrates of duration MMN have not yet been investigated. We therefore studied how duration transitions in an auditory stimulus train are represented in neurons in the primary auditory cortex of anesthetized guinea pigs. Two types of neuronal responses to the context of changes in stimulus duration were found. One was a reduced response as the duration of the preceding stimulus was increased. Second was an enhancement of the late components of the response... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2935695 Fri, 23 Oct 2009 00:00:00 +0100 2935695 http://www.medworm.com/index.php?rid=2927846&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%3D19854255%26dopt%3DAbstract Authors: Bao J, Ohlemiller KK Spiral ganglion neurons (SGNs) are the relay station for auditory information between hair cells and central nervous system. Age-related decline of auditory function due to SGN loss can not be ameliorated by hearing aids or cochlear implants. Recent findings clearly indicate that survival of SGNs during aging depends on genetic and environmental interactions, which can be demonstrated at the systemic, tissue, cellular, and molecular levels. At the systemic level, both insulin/insulin-like growth factor-1 and lipophilic/steroid hormone pathways influence SGN survival during aging. At the level of organ of the Corti, it is difficult to determine whether age-related SGN loss is primary or secondary degeneration. However, a late stage of SGN degeneration may b... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2927846 Thu, 22 Oct 2009 00:00:00 +0100 2927846 http://www.medworm.com/index.php?rid=2927847&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%3D19853647%26dopt%3DAbstract Authors: Cruickshanks KJ, Nondahl DM, Tweed TS, Wiley TL, Klein BE, Klein R, Chappell R, Dalton DS, Nash SD The purpose of this study was to determine the 10-yr cumulative incidence of hearing impairment and associations of education, occupation and noise exposure history with the incidence of hearing impairment in a population-based cohort study of 3753 adults ages 48-92 years at the baseline examinations during 1993-1995 in Beaver Dam, WI. Hearing thresholds were measured at baseline, 2.5 yr, 5 yr, and 10-yr follow-up examinations. Hearing impairment was defined as a pure-tone average (PTA) > 25 dB HL at 500, 1000, 2000, and 4000 Hz. Demographic characteristics and occupational histories were obtained by questionnaire. The 10-yr cumulative incidence of hearing impairment was 37.2%... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2927847 Wed, 21 Oct 2009 00:00:00 +0100 2927847 http://www.medworm.com/index.php?rid=2927848&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%3D19853029%26dopt%3DAbstract Authors: Lukashkin AN, Richardson GP, Russell IJ This review is concerned with experimental results that reveal multiple roles for the tectorial membrane in active signal processing in the mammalian cochlea. We discuss the dynamic mechanical properties of the tectorial membrane as a mechanical system with several degrees of freedom and how its different modes of movement can lead to hair-cell excitation. The role of the tectorial membrane in distributing energy along the cochlear partition and how it channels this energy to the inner hair cells is described. PMID: 19853029 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2927848 Tue, 20 Oct 2009 00:00:00 +0100 2927848 http://www.medworm.com/index.php?rid=2924249&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%3D19850116%26dopt%3DAbstract Authors: Bahmer A, Polak M, Baumann U Biphasic electrical pulses are the standard stimulation pulses in current cochlear implants. In auditory brainstem recordings biphasic pulses generate a significant artifact that disrupts brainstem responses, which are magnitudes smaller. Triphasic pulses may minimize artifacts by restoring the neural membrane to its resting potential faster than biphasic pulses and make auditory brainstem responses detection easier. We compared biphasic pulses with triphasic and precision triphasic pulses to evoke brainstem responses in human subjects. For this purpose, electrically evoked brainstem response audiometry was performed in 10 (11 ears) cochlear implant patients. Artifacts and brainstem responses evoked by bi- and triphasic stimulation were analyzed. A... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2924249 Mon, 19 Oct 2009 00:00:00 +0100 2924249 http://www.medworm.com/index.php?rid=2912869&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%3D19840840%26dopt%3DAbstract Authors: Mazurek B, Haupt H, Joachim R, Klapp BF, Stöver T, Szczepek AJ Exposure to harsh environment induces stress reactions that increase probability of survival. Stress influences the endocrine, nervous and immune systems and affects the functioning of a variety of organs. Numerous researchers demonstrated that a 24-hour exposure to an acoustic rodent repellent provokes stress reaction in exposed animals. In addition to the activated hypothalamus-pituitary-adrenal (HPA) axis, exposed animals had pathological reactions in the reproductive organs, bronchia and skin. Here, we examined the effect of above stress model on the auditory system of Wistar rats. We found that 24-hour stress decreases the thresholds and increases the amplitudes of auditory brainstem responses and distort... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2912869 Thu, 15 Oct 2009 23:00:00 +0100 2912869 http://www.medworm.com/index.php?rid=2912868&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%3D19840841%26dopt%3DAbstract Authors: Stronks HC, Versnel H, Prijs VF, Klis SF There is increasing interest in the use of electro-acoustical stimulation in people with a cochlear implant that have residual low-frequency hearing in the implanted ear. This raises the issue of how electrical and acoustical stimulation interact in the cochlea. We have investigated the effect of electrical stimulation on the acoustically evoked compound action potential (CAP) in normal-hearing guinea pigs. CAPs were evoked by tone bursts, and electric stimuli were delivered at the base of the cochlea using extracochlear electrodes. CAPs could be suppressed by electrical stimulation under various conditions. The dependence of CAP suppression on several parameters was investigated, including frequency and level of the acoustic stimulus, ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2912868 Thu, 15 Oct 2009 23:00:00 +0100 2912868 http://www.medworm.com/index.php?rid=2912871&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%3D19835941%26dopt%3DAbstract Authors: Ashmore J PMID: 19835941 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2912871 Mon, 12 Oct 2009 23:00:00 +0100 2912871 http://www.medworm.com/index.php?rid=2912870&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%3D19835942%26dopt%3DAbstract Authors: Qin Z, Wood M, Rosowski JJ In order to discriminate conductive hearing loss from sensorineural impairment, quantitative measurements were used to evaluate the effect of artificial conductive pathology on distortion product otoacoustic emissions (DPOAEs), auditory brainstem responses (ABRs) and laser Doppler vibrometry (LDV) in mice. The conductive manipulations were created by perforating the pars flaccida of the tympanic membrane, filling or partially filling the middle-ear cavity with saline, fixing the ossicular chain, and interrupting the incudo-stapedial joint. In the saline-filled and ossicular-fixation groups, averaged DPOAE thresholds increased relative to the control state by 20 to 36 dB and 25 to 39 dB respectively with the largest threshold shifts occurring at frequ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2912870 Mon, 12 Oct 2009 23:00:00 +0100 2912870 http://www.medworm.com/index.php?rid=2887640&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%3D19818839%26dopt%3DAbstract Authors: Dierkes K, Lindner B, Jülicher F PMID: 19818839 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2887640 Tue, 06 Oct 2009 23:00:00 +0100 2887640 http://www.medworm.com/index.php?rid=2887639&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%3D19818840%26dopt%3DAbstract Authors: Soons JA, Aernouts J, Dirckx JJ For the purpose of creating a finite element model of the middle ear, the ossicles can be modelled as rigid bodies or as linear elastic materials. The general elasticity parameters used are usually measured on larger bones like the femur. In order to obtain a highly realistic model, the actual elastic modulus (Young's modulus) of the ossicles themselves is needed. We developed a novel 2-needle indentation method of determining the Young's modulus of small samples based on Sneddon's solution. We introduce the second needle in such a way that small specimens can be clamped between the 2 needles and a symmetry plane is obtained, so that geometry-dependent sample deformations are avoided. A finite element calculated correction factor is used to comp... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2887639 Tue, 06 Oct 2009 23:00:00 +0100 2887639 http://www.medworm.com/index.php?rid=2887638&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%3D19818841%26dopt%3DAbstract Authors: Meaud J, Grosh K In most models of the mammalian cochlea, either mathematical or conceptual, the sensitivity of the BM to low level acoustic stimulus is explained by the presence of outer hair cell (OHC) somatic motility. However, recent experimental evidence indicates that OHC hair bundle (HB) motility can operate with submillisecond time constants. In this paper, we implement a simple phenomenological mathematical model of HB motility, based on the ansatz that HB forcing adds mechanical energy to the system. Our preliminary predictions using models that combine HB and somatic OHC motility indicate that HB motility is not necessary for cochlear amplification while OHC somatic motility is necessary. However we show how HB motility could work in synergy with OHC somatic motilit... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2887638 Tue, 06 Oct 2009 23:00:00 +0100 2887638 http://www.medworm.com/index.php?rid=2887644&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%3D19818388%26dopt%3DAbstract Authors: Fettiplace R, Hackney C The strengths and weakness of the outer hair cell bundle and somatic motors as the source of cochlear amplification are discussed. PMID: 19818388 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2887644 Mon, 05 Oct 2009 23:00:00 +0100 2887644 http://www.medworm.com/index.php?rid=2887643&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%3D19818389%26dopt%3DAbstract Authors: Avan P, Petit C PMID: 19818389 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2887643 Mon, 05 Oct 2009 23:00:00 +0100 2887643 http://www.medworm.com/index.php?rid=2887642&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%3D19818390%26dopt%3DAbstract Authors: Brownell WE Acoustic vibrations enter and neuronal action potentials leave the inner ear. An interplay of mechanical and electrical energy results in hair cell receptor potentials that ultimately trigger neurotransmitter release at the afferent synapse. The diffusion of neurotransmitter across the synaptic cleft depolarizes 8(th) nerve terminals and initiates action potentials that travel to the central nervous system. The action potentials encode information about the spectral and temporal content of environmental sounds. The ability to localize predator or prey is improved by analyzing sounds over a wide range of frequencies resulting in an evolutionary selection pressure for detecting ever higher frequencies. Nature has incorporated diverse strategies to overcome physical c... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2887642 Mon, 05 Oct 2009 23:00:00 +0100 2887642 http://www.medworm.com/index.php?rid=2887641&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%3D19818391%26dopt%3DAbstract Authors: Zou J, Zhang W, Poe D, Zhang Y, Ramadan UA, Pyykkö I Magnetic resonance imaging (MRI), supplemented by contrast agents, is a powerful tool that can be used to visualise the structures of the inner ear in vivo and assess some aspects of physiology, such as the permeability of agents through membranes. The mouse is an excellent animal species for investigating human diseases, including hearing loss but detailed MRI studies with contrast have not been reported. In the present work, we aimed to demonstrate the limits of MR imaging resolution of the fine inner ear structures in the mouse and to explore the permeability of the intracochlear barriers to gadolinium- tetra-azacyclo-dodecane-tetra-acetic acid (Gd-DOTA) administered by intravenous injection (IV) or intratympanic (IT... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2887641 Mon, 05 Oct 2009 23:00:00 +0100 2887641 http://www.medworm.com/index.php?rid=2866099&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%3D19800957%26dopt%3DAbstract Authors: Getzmann S, Lewald J The effect of the type of the auditory motion stimulus on neural correlates of motion processing were investigated using high-density electroencephalography. Sound motion was implemented by (a) gradual shifts in interaural time or (b) level difference; (c) motion of virtual 3D sound sources; or (d) successive activation of 45 loudspeakers along the horizontal plane. In a subset of trials, listeners (N = 20) performed a two-alternative forced-choice motion discrimination task. Each trial began with a stationary phase of the acoustic stimulus in a central position, immediately followed by a motion of the stimulus. The motion onset elicited a specific cortical response that was dominated by large negative and positive deflections, the so-called change-N1 and ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2866099 Wed, 30 Sep 2009 23:00:00 +0100 2866099 http://www.medworm.com/index.php?rid=2866098&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%3D19800958%26dopt%3DAbstract Authors: Harris KC, Eckert MA, Ahlstrom JB, Dubno JR Differences in gap detection for younger and older adults have been shown to vary with the complexity of the task or stimuli, but the factors that contribute to these differences remain unknown. To address this question, we examined the extent to which age-related differences in processing speed and workload predicted age-related differences in gap detection. Gap detection thresholds were measured for 10 younger and 11 older adults in two conditions that varied in task complexity but used identical stimuli: (1) gap location fixed at the beginning, middle, or end of a noise burst and (2) gap location varied randomly from trial to trial from the beginning, middle, or end of the noise. We hypothesized that gap location uncertainty would... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2866098 Wed, 30 Sep 2009 23:00:00 +0100 2866098 http://www.medworm.com/index.php?rid=2859289&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%3D19796672%26dopt%3DAbstract Authors: Nishioka R, Takeda T, Kakigi A, Okada T, Takebayashi S, Taguchi D, Nishimura M, Hyodo M Recently, considerable evidence has been accumulated to support the novel view that water homeostasis in the inner ear is regulated via the vasopressin-aquaporin 2 (VP-AQP2) system in the same fashion as in the kidney. Indeed, multiple subtypes of AQPs including AQP-2 are reported to be expressed in the cochlea. However, the mechanism that underlies VP-AQP2 mediated water homeostasis remains to be elucidated. In the present study, the localization of AQP-1, -2, -3, -4, -5, -7, -8, -9, and vasopressin type 2 receptor (V(2)-R) in the stria vascularis (SV) were molecular biologically and immunohistochemically examined to evaluate the role of the AQP water channel system in water homeostasis of... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2859289 Sun, 27 Sep 2009 23:00:00 +0100 2859289 http://www.medworm.com/index.php?rid=2856228&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%3D19788920%26dopt%3DAbstract Authors: Micheyl C, Oxenham AJ Harmonic complex tones are a particularly important class of sounds found in both speech and music. Although these sounds contain multiple frequency components, they are usually perceived as a coherent whole, with a pitch corresponding to the fundamental frequency (F0). However, when two or more harmonic sounds occur concurrently, e.g., at a cocktail party or in a symphony, the auditory system must separate harmonics and assign them to their respective F0s so that a coherent and veridical representation of the different sounds sources is formed. Here we review both psychophysical and neurophysiological (single-unit and evoked-potential) findings, which provide some insight into how, and how well, the auditory system accomplishes this task. A survey of com... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2856228 Fri, 25 Sep 2009 23:00:00 +0100 2856228 http://www.medworm.com/index.php?rid=2847389&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%3D19786082%26dopt%3DAbstract Authors: Manley GA The traditional view that a tympanic middle ear developed only once, when vertebrates made the transition from fish in water to land-living animals, has been shown to be incorrect. Middle ears with a tympanum connected by one or more ossicles to the cochlea developed very much later in evolutionary history and independently in many amniote vertebrate lineages - most now extinct. The mammalian middle ear is unique but it is not simply an "improved" single-ossicle middle ear. It is a radical and fortuitous new development that owes its origin more to changes in feeding patterns than to hearing. It happened to transmit higher-frequency sounds better than single-ossicle middle ears and enabled the evolution of the high upper-frequency hearing limits of most mammals. Para... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2847389 Thu, 24 Sep 2009 23:00:00 +0100 2847389 http://www.medworm.com/index.php?rid=2847388&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%3D19786083%26dopt%3DAbstract Authors: Humes LE, Kewley-Port D, Fogerty D, Kinney D Psychophysical data on hearing sensitivity and various measures of supra-threshold auditory temporal processing are presented for large groups of young (18-35 y), middle-aged (40-55 y) and older (60-89 y) adults. Hearing thresholds were measured at 500, 1414 and 4000 Hz. Measures of temporal processing included gap-detection thresholds for bands of noise centered at 1000 and 3500 Hz, stimulus onset asynchronies for monaural and dichotic temporal-order identification for brief vowels, and stimulus onset/offset asynchronies for the monaural temporal masking of vowel identification. For all temporal-processing measures, the impact of high-frequency hearing loss in older adults was minimized by a combination of low-pass filtering the st... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2847388 Thu, 24 Sep 2009 23:00:00 +0100 2847388 http://www.medworm.com/index.php?rid=2839589&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%3D19781610%26dopt%3DAbstract Conclusion: The menopause appears to act as a trigger of a relatively rapid age-related hearing decline in healthy women, starting in the left ear. PMID: 19781610 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2839589 Mon, 21 Sep 2009 23:00:00 +0100 2839589 http://www.medworm.com/index.php?rid=2835777&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%3D19778595%26dopt%3DAbstract Authors: Aernouts J, Soons JA, Dirckx JJ Correct quantitative parameters to describe tympanic membrane elasticity are an important input for realistic modeling of middle ear mechanics. In the past, several attempts have been made to determine tympanic membrane elasticity from tensile experiments on cut-out strips. The strains and stresses in such experiments may be far out of the physiologically relevant range and the elasticity parameters are only partially determined. We developed a setup to determine tympanic membrane elasticity in situ, using a combination of point micro-indentation and Moiré profilometry. The measuring method was tested on latex phantom models of the tympanic membrane, and our results show that the correct parameters can be determined. These parameters were c... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2835777 Sun, 20 Sep 2009 23:00:00 +0100 2835777 http://www.medworm.com/index.php?rid=2832532&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%3D19772906%26dopt%3DAbstract Authors: Hughes LF, Turner JG, Parrish JL, Caspary DM Presbycusis can be considered a slow age-related peripheral and central deterioration of auditory function which manifests itself as deficits in speech comprehension, especially in noisy environments. The present study examined neural correlates of a simple broadband noise stimulus in primary auditory cortex (A1) of young and aged Fisher-Brown Norway (FBN) rats. Age-related changes in unit responses to broadband noise-bursts and spontaneous activity were simultaneously recorded across A1 layers using a single shank, 16-channel electrode. Noise bursts were presented contralateral to the left A1 at 80 dB SPL. Aged A1 units displayed increased spontaneous (29%), peak (24%), and steady state response rates (38%) than did young A1 units.... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2832532 Fri, 18 Sep 2009 23:00:00 +0100 2832532 http://www.medworm.com/index.php?rid=2832531&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%3D19772907%26dopt%3DAbstract Authors: Keefe DH, Fitzpatrick D, Liu YW, Sanford CA, Gorga MP A wideband (WB) aural acoustical test battery of middle-ear status, including acoustic-reflex thresholds (ARTs) and acoustic-transfer functions (ATFs, i.e., absorbance and admittance) was hypothesized to be more accurate than 1-kHz tympanometry in classifying ears that pass or refer on a newborn hearing screening (NHS) protocol based on otoacoustic emissions. Assessment of middle-ear status may improve NHS programs by identifying conductive dysfunction and cases in which auditory neuropathy exists. Ipsilateral ARTs were assessed with a stimulus including four broadband-noise or tonal activator pulses alternating with five clicks presented before, between and after the pulses. The reflex shift was defined as the difference b... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2832531 Fri, 18 Sep 2009 23:00:00 +0100 2832531 http://www.medworm.com/index.php?rid=2832530&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%3D19772908%26dopt%3DAbstract Authors: Cosgrove D, Zallocchi M PMID: 19772908 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2832530 Fri, 18 Sep 2009 23:00:00 +0100 2832530 http://www.medworm.com/index.php?rid=2832529&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%3D19772909%26dopt%3DAbstract Authors: Gan RZ, Dai C, Wang X, Nakmali D, Wood MW Implantable middle ear hearing devices are emerging as an effective technology for patients with mild to moderately severe sensorineural hearing loss. Several devices with electromagnetic or piezoelectric transducers have been investigated or developed in the US and Europe since 1990. This paper reports a totally implantable hearing system (TIHS) currently under investigation in Oklahoma. The TIHS consists of implant transducer (magnet), implantable coil and microphone, DSP-audio signal processor, rechargeable battery, and remote control unit. The design of TIHS is based on a 3D finite element model of the human ear and the analysis of electromagnetic coupling of the transducer. Function of the TIHS is characterized over the auditory f... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2832529 Fri, 18 Sep 2009 23:00:00 +0100 2832529 http://www.medworm.com/index.php?rid=2824792&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%3D19766180%26dopt%3DAbstract Authors: Sim JH, Chatzimichalis M, Huber AM In the surgical treatment of otosclerosis, the coupling between the stapes prosthesis and the long process of the incus is critical. After surgery, connective tissue and mucosa may grow over the coupling area and thereby influence the sound transmission properties of the incus-prosthesis interface. It was the hypothesis of this study that tissue ongrowth in the incus-prosthesis interface has little influence on sound transmission following stapes surgery. The goals of the study were to: 1) investigate the extent of postoperative tissue ongrowth over the stapes prosthesis; 2) objectively evaluate intra- and postoperative sound transmission properties of revision stapes surgery and compare the findings to those from primary surgery; 3) quantify... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2824792 Tue, 15 Sep 2009 23:00:00 +0100 2824792 http://www.medworm.com/index.php?rid=2810369&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%3D19761823%26dopt%3DAbstract Authors: Sha SH, Chen FQ, Schacht J We have previously reported the activation of cell death pathways in the sensory cells of the aging cochlea. Here we investigate age-associated changes in survival mechanisms focusing on phosphatidylinositol 3,4,5-trisphosphate (PIP(3))/Akt signaling. The animal model is the CBA/J mouse of 18 months of age prior to the onset of major functional loss (ABR thresholds, 26 +/- 8 dB SPL) which is compared to young animals of 3 months of age (ABR thresholds, 19 +/- 7 dB SPL). Immunostaining on cochlear cryosections revealed a wide-spread distribution of PIP(3) in the cochlea which was markedly attenuated in old animals in inner and outer hair cells, Deiters cells and pillar cells. Protein levels of the lipid phosphatase PTEN which regulates PIP(3) increase... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2810369 Sun, 13 Sep 2009 23:00:00 +0100 2810369 http://www.medworm.com/index.php?rid=2798759&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%3D19748564%26dopt%3DAbstract Authors: Brown CA, Bacon SP Speech reception in noise is an especially difficult problem for listeners with hearing impairment as well as for users of cochlear implants (CIs). One likely cause of this is an inability to 'glimpse' a target talker in a fluctuating background, which has been linked to deficits in temporal fine-structure processing. A fine-structure cue that has the potential to be beneficial for speech reception in noise is fundamental frequency (F0). A challenging problem, however, is delivering the cue to these individuals. The benefits to speech intelligibility of F0 for both listeners with hearing impairment and users of CIs are reviewed, as well as various methods of delivering F0 to these listeners. PMID: 19748564 [PubMed - as supplied by publisher] (Source: Hea... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2798759 Wed, 09 Sep 2009 23:00:00 +0100 2798759 http://www.medworm.com/index.php?rid=2782709&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%3D19735708%26dopt%3DAbstract Authors: Bielefeld EC, Tanaka C, Chen GD, Henderson D Numerous techniques have been tested to attempt to prevent the onset or progression of age-related hearing loss (ARHL): raising the animals in an augmented acoustic environment (used successfully in mouse and rat models), enhancing the antioxidant defenses with exogenous antioxidant treatments (used with mixed results in mouse and rat models), raising the animals with a calorie restricted diet (used successfully in mouse and rat models), restoring lost endocochlear potential voltage with exogenous electrical stimulation (used successfully in the Mongolian gerbil model), and hypothetical enhancement of outer hair cell electromotility with salicylate therapy. Studies of human ARHL have revealed a set of unique hearing loss configurati... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2782709 Thu, 03 Sep 2009 23:00:00 +0100 2782709 http://www.medworm.com/index.php?rid=2775410&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%3D19732818%26dopt%3DAbstract Authors: Eastwood H, Pinder D, James D, Chang A, Galloway S, Richardson R, O'Leary S Protection of residual hearing after cochlear implant surgery can improve the speech and music perception of cochlear implant recipients, particularly in the presence of background noise. Surgical trauma and chronic inflammation are thought to be responsible for a significant proportion of residual hearing loss after surgery. Local delivery of the anti-oxidant precursor n-acetyl cysteine (NAC) to the cochlea via round window 30 minutes prior to surgery, increased the level of residual hearing at 24-32 kHz four weeks post surgery compared to controls. The hearing protection was found in the basal turn near the site of implantation. Coincidentally, the basal turn was also the location that sustained the ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2775410 Mon, 31 Aug 2009 23:00:00 +0100 2775410 http://www.medworm.com/index.php?rid=2762280&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%3D19720125%26dopt%3DAbstract Authors: Koka K, Holland NJ, Lupo JE, Jenkins HA, Tollin DJ Mechanical stimulation of the round window (RW) with an active middle ear prosthesis (AMEP) has shown functional benefit in clinical reports in patients with mixed hearing loss (MHL). Further objective physiological data on the efficacy of RW stimulation is needed, however, to demonstrate that RW stimulation with an AMEP can generate input to the inner ear comparable to acoustic input. Cochlear microphonic (CM) and mechanical (stapes velocity) responses to sinusoidal stimuli were measured by electrode and laser Doppler vibrometry in 8 chinchillas in response to normal acoustic stimulation via sealed calibrated insert earphones and to AMEP stimulation (Otologics MET, Boulder CO USA) of the RW with and without lateral ossicular ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2762280 Thu, 27 Aug 2009 23:00:00 +0100 2762280 http://www.medworm.com/index.php?rid=2752653&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%3D19715747%26dopt%3DAbstract Authors: Ding D, Jiang H, Salvi RJ Concurrent administration of a high dose of gentamicin (GM; 125 mg/kg IM) and ethacrynic acid (EA; 40 mg/kg IV) results in rapid destruction of virtually all cochlear hair cells; however, the cell death signaling pathways underlying this rapid form of hair-cell degeneration are unclear. To elucidate the mechanisms underlying GM/EA-mediated cell death, several key cell death markers were assessed in the chinchilla cochlea during the early stages of degeneration. In the middle and basal turns of the cochlea, massive hair-cell loss including destruction of the stereocilia and cuticular plate occurred 12 h after GM/EA treatment. Condensation and fragmentation of outer hair-cell nuclei, morphological features of apoptosis, were first observed 5-6 h post-tr... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2752653 Mon, 24 Aug 2009 23:00:00 +0100 2752653 http://www.medworm.com/index.php?rid=2742241&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%3D19706320%26dopt%3DAbstract In conclusion, our results show partial support for frequency-specific enhancement. PMID: 19706320 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2742241 Fri, 21 Aug 2009 23:00:00 +0100 2742241 http://www.medworm.com/index.php?rid=2735712&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%3D19703532%26dopt%3DAbstract Authors: Fallon JB, Shepherd RK, Brown M, Irvine DR The use of cochlear implants in patients with severe hearing losses but residual low-frequency hearing raises questions concerning the effects of chronic intracochlear electrical stimulation (ICES) on cortical responses to auditory and electrical stimuli. We investigated these questions by studying responses to tonal and electrical stimuli in primary auditory cortex (AI) of two groups of neonatally-deafened cats with residual high-threshold, low-frequency hearing. One group were implanted with a multi-channel intracochlear electrode at eight weeks of age, and received chronic ICES for up to nine months before cortical recording. Cats in the other group were implanted immediately prior to cortical recording as adults. In all cats in bo... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2735712 Thu, 20 Aug 2009 23:00:00 +0100 2735712 http://www.medworm.com/index.php?rid=2730514&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%3D19699286%26dopt%3DAbstract Authors: Gutschalk A, Oldermann K, Rupp A The rate perception of tone sequences reflects the physical repetition rate for identical sound elements. More complex sequences are perceived at the physical rate or at lower rates, depending on perceptual organization. Here, we used magnetoencephalography and psychophysical studies to evaluate the possible relationship between rate perception of such rapid, 40-Hz tone trains and the 40-Hz steady-state response (SSR) in human primary auditory cortex. In Experiment 1, the 40-Hz SSR evoked by monotone sequences of 1000 and 600 Hz were compared to the response evoked by alternating-tone sequences of the same frequencies. The results showed that the 40-Hz SSR for the alternating-tones was attenuated compared to the monotones. In Experiment 2, freq... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2730514 Tue, 18 Aug 2009 23:00:00 +0100 2730514 http://www.medworm.com/index.php?rid=2730513&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%3D19699287%26dopt%3DAbstract Authors: Melcher JR, Levine RA, Bergevin C, Norris B Sound-evoked fMRI activation of the inferior colliculi (IC) was compared between tinnitus and non-tinnitus subjects matched in threshold (normal), age, depression, and anxiety. Subjects were stimulated with broadband sound in an "on/off" fMRI paradigm with and without on-going sound from the scanner coolant pump. (1) With pump sounds off, the tinnitus group showed greater stimulus-evoked activation of the IC than the non-tinnitus group, suggesting abnormal gain within the auditory pathway of tinnitus subjects. (2) Having pump sounds on reduced activation in the tinnitus, but not the non-tinnitus group. This result suggests response saturation in tinnitus subjects, possibly occurring because abnormal gain increased response amplitude ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2730513 Tue, 18 Aug 2009 23:00:00 +0100 2730513 http://www.medworm.com/index.php?rid=2730515&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%3D19698773%26dopt%3DAbstract Authors: Krueger J, Royal DW, Fister MC, Wallace MT Previous work has established that the spatial receptive fields (SRFs) of multisensory neurons in the cerebral cortex are strikingly heterogeneous, and that SRF architecture plays an important deterministic role in sensory responsiveness and multisensory integrative capacities. The initial part of this contribution serves to review these findings detailing the key features of SRF organization in cortical multisensory populations by highlighting work from the cat anterior ectosylvian sulcus (AES). In addition, we have recently conducted parallel studies designed to examine SRF architecture in the classic model for multisensory studies, the cat superior colliculus (SC), and we present some of the preliminary observations from the SC her... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2730515 Mon, 17 Aug 2009 23:00:00 +0100 2730515 http://www.medworm.com/index.php?rid=2725431&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%3D19695320%26dopt%3DAbstract Authors: Luo F, Wang Q, Farid N, Liu X, Yan J The cochlear nucleus (CN) is the first sound processing center in the central auditory system that receives the almost unprocessed auditory information from the auditory periphery. The functional organization of the CN has been studied to a great extent in many mammals, including the cat, rat and bat. Yet, despite the general usefulness of the mouse, including the availability of various inbred strains and gene-manipulated lines, our current understanding of the mouse CN remains limited. The purpose of this study was to illustrate the functional organization of the CN in C57 mice, using an electrophysiological approach. Our results showed that the auditory response properties of CN neurons were similar in all three of the CN subdivisions. S... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2725431 Sun, 16 Aug 2009 23:00:00 +0100 2725431 http://www.medworm.com/index.php?rid=2692186&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%3D19666099%26dopt%3DAbstract Authors: Park HJ, Kim HJ, Bae GS, Seo SW, Kim DY, Jung WS, Kim MS, Song MY, Kim EK, Kwon KB, Hwang SY, Song HJ, Park CS, Park RK, Chong MS, Park SJ Glycogen synthase kinase-3 (GSK-3) plays an important role in the regulation of apoptosis. However, the role of GSK-3 in the auditory system remains unknown. Here we examined whether the GSK-3-specific inhibitors, SB 216763 and LiCl, could protect against cisplatin-induced cytotoxicity of auditory cells. GSK-3 was activated by cisplatin treatment of HEI-OC1 cells. SB 216763 or LiCl treatments inhibited cisplatin-induced apoptosis in a dose-dependent manner and activated caspase-9, -8 and -3. In rat primary explants of the organ of Corti, SB 216763 or LiCl treatments completely abrogated the cisplatin-induced destruction of outer hair cell a... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2692186 Thu, 06 Aug 2009 23:00:00 +0100 2692186 http://www.medworm.com/index.php?rid=2675409&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%3D19651198%26dopt%3DAbstract Authors: Knipper M, Zimmermann U, Müller M Molecular changes caused by sensory trauma and subsequent structural alterations of the central nervous system are only beginning to be identified. In most cases, the generation of tinnitus can be linked to damage of the peripheral auditory system, probably even in cases where hearing impairment cannot be assessed by audiometry. Within a common view, acoustic trauma and salicylate induce abnormal excitability at the level of the brainstem, subcortical and cortical level that may be related to tinnitus.The present review summarizes studies emphasizing a crucial role of molecular events that occur in the cochlea exhibiting the potential to alter the network activity in distinct areas of the brain, including the limbic system. We proceed fro... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2675409 Thu, 30 Jul 2009 23:00:00 +0100 2675409 http://www.medworm.com/index.php?rid=2675408&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%3D19651199%26dopt%3DAbstract This article summarizes evidence for a reorganization of multisensory brain areas and reduced crossmodal interactions on the behavioral level following congenital visual deprivation. PMID: 19651199 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2675408 Thu, 30 Jul 2009 23:00:00 +0100 2675408 http://www.medworm.com/index.php?rid=2668662&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%3D19647788%26dopt%3DAbstract Authors: Howard MF, Poeppel D We examine lateralization in the evoked magnetic field response to a click stimulus, observing that lateralization effects previously demonstrated for tones, noise, frequency modulated sweeps and certain syllables are also observed for (acoustically simpler) clicks. These effects include a difference in the peak latency of the M100 component of the evoked field waveform such that the peak consistently appears earlier in the right hemisphere, as well as rightward lateralization of field amplitude during the rise of the M100 component. Our review of previous findings on M100 lateralization, taken together with our data on the click-evoked response, leads to the hypothesis that these lateralization effects are elicited by stimuli containing a sharp sound ener... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2668662 Wed, 29 Jul 2009 23:00:00 +0100 2668662 http://www.medworm.com/index.php?rid=2668661&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%3D19647789%26dopt%3DAbstract Authors: Pienkowski M, Eggermont JJ We recently reported that passive exposure for at least 4 months of adult cats to a 2-octave-wide tone pip ensemble at 80 dB SPL, decreased the responsiveness of primary auditory cortex (AI) to sound frequencies in the exposure band, and increased the responsiveness to frequencies at the outer edges of the band. Here we expand on this by demonstrating qualitatively similar plasticity for a 6-week exposure level of 68 dB SPL. Though no peripheral hearing loss is induced by the exposure, the resulting reorganization of the AI tonotopic map resembles that following a restricted lesion of the sensory epithelium. Most exposure-induced effects were likely present in the thalamus, as deduced from changes in local field potentials, but were further modified ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2668661 Wed, 29 Jul 2009 23:00:00 +0100 2668661 http://www.medworm.com/index.php?rid=2661028&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%3D19643173%26dopt%3DAbstract Authors: Lin CY, Wu JL, Shih TS, Tsai PJ, Sun YM, Guo YL The generation of Reactive Oxygen Species (ROS) is thought to be part of the mechanism underlying noise-induced hearing loss (NIHL). Glutathione is an important cellular antioxidant that limits cell damage by ROS. We aimed to determine the effect of genetic polymorphisms of glutathione S-transferase (GST) T1, GSTM1, and GSTP1, on temporary threshold shift (TTS) in 58 noise-exposed male workers from a steel factory. The pre-shift hearing impairment at high frequency (HF, average of 3, 4 and 6 kHz) was 30.7dB HL (S.D.=19.3). The amount of daily noise exposure was 83.0dBA (S.D.=5.0). Noise-induced TTS at HF by pure-tone audiometry (PTA) was related to the daily noise exposure (p<0.05). Based on combinatory analysis, we found that... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2661028 Sun, 26 Jul 2009 23:00:00 +0100 2661028 http://www.medworm.com/index.php?rid=2661027&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%3D19643174%26dopt%3DAbstract Authors: Lu E, Llano DA, Sherman SM We studied the distributions of calretinin and calbindin immunoreactivity in subdivisions of the mouse medial geniculate body and the adjacent paralaminar nuclei. We found that the vast majority of labeled cells in the dorsal division of the medial geniculate body were immunoreactive for calbindin only, whereas most of the remaining labeled cells were double-labeled. Very few calretinin+ only cells were observed. By contrast, we observed significant proportions of calbindin+ only, calretinin+ only and double-labeled cells in the medial division of the medial geniculate body. Further, the distributions of calbindin-only, calretinin-only and double-labeled cells did not differ between the medial division of the medial geniculate body, the supragenicula... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2661027 Sun, 26 Jul 2009 23:00:00 +0100 2661027 http://www.medworm.com/index.php?rid=2646278&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%3D19631727%26dopt%3DAbstract Authors: Wild JM, Krützfeldt NO, Kubke MF The presence and nature of a descending projection from the ventral nucleus of the lateral lemniscus (LLV) to the cochlear nuclei (NA, NM) and the third-order nucleus laminaris (NL) was investigated in a songbird using tract tracing and GAD immunohistochemistry. Tracer injections into LLV produced anterograde label in the ipsilateral NA, NM and NL, which was found not to be GABAergic. Double retrograde labelling from LLV and NA/NM/NL ruled out the possibility that the LLV projection actually arose from collaterals of superior olivary projections to NA/NM/NL. The LLV projection may be involved in the discrimination of laterality of auditory input. PMID: 19631727 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2646278 Tue, 21 Jul 2009 23:00:00 +0100 2646278 http://www.medworm.com/index.php?rid=2635137&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%3D19622390%26dopt%3DAbstract Authors: Finlayson PG, Kaltenbach JA Electrophysiological recordings in the dorsal cochlear nucleus (DCN) were conducted to determine the nature of changes in single unit activity following intense sound exposure and how they relate to changes in multiunit activity. Single and multiunit spontaneous discharge rates and auditory response properties were recorded from the left DCN of tone exposed and control hamsters. The exposure condition consisted of a 10 kHz tone presented in the free-field at a level of 115 dB for 4 hrs. Recordings conducted at 5-6 days postexposure revealed several important changes. Increases in multiunit spontaneous neural activity were observed at surface and subsurface levels of the DCN of exposed animals, reaching a peak at intermediate depths corresponding to ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2635137 Fri, 17 Jul 2009 23:00:00 +0100 2635137 http://www.medworm.com/index.php?rid=2628679&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%3D19619628%26dopt%3DAbstract Authors: Smiley JF, Falchier A Functional studies have demonstrated multisensory responses in auditory cortex, even in the primary and early auditory association areas. The features of somatosensory and visual responses in auditory cortex suggest that they are involved in multiple processes including spatial, temporal and object-related perception. Tract tracing studies in monkeys have demonstrated several potential sources of somatosensory and visual inputs to auditory cortex. These include potential somatosensory inputs from the retroinsular (RI) and granular insula (Ig) cortical areas, and from the thalamic posterior (PO) nucleus. Potential sources of visual responses include peripheral field representations of areas V2 and prostriata, as well as the superior temporal polysensory ar... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2628679 Thu, 16 Jul 2009 23:00:00 +0100 2628679 http://www.medworm.com/index.php?rid=2628678&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%3D19619629%26dopt%3DAbstract Authors: Shechter B, Dobbins HD, Marvit P, Depireux DA We previously characterized the steady-state spectro-temporal tuning properties of cortical cells with respect to broadband sounds by using sounds with sinusoidal spectro-temporal modulation envelope where spectral density and temporal periodicity were constant over several seconds. However, since speech and other natural sounds have spectro-temporal features that change substantially over milliseconds, we study the dynamics of tuning by using stimuli of constant overall intensity, but alternating between a flat spectro-temporal envelope and a modulated envelope with well defined spectral density and temporal periodicity. This allows us to define the tuning of cortical cells to speech-like and other rapid transitions, on the order ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2628678 Thu, 16 Jul 2009 23:00:00 +0100 2628678 http://www.medworm.com/index.php?rid=2622242&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%3D19615433%26dopt%3DAbstract Authors: Bal R, Baydas G Neurons in the cochlear nucleus (CN) have distinct anatomical and biophysical specializations and extract various facets of auditory information which are transmitted to the higher auditory centres. The aim of the present study was to determine if the principal neurons (stellate, bushy and octopus cells) of the ventral cochlear nucleus (VCN) in two- week-old dog brain slices share common electrophysiological properties with the principal neurons of mouse VCN. Stellate cells (n=21, of which 3 were anatomically identified), fired large, regular trains of action potentials in response to depolarizing current pulses. Input resistance and membrane time constant were 176 +/- 35.9 MOmega (n=21) and 8.8 +/- 1.4 ms (n=21) respectively. Bushy cells, (n=6, of which 3 were... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2622242 Mon, 13 Jul 2009 23:00:00 +0100 2622242 http://www.medworm.com/index.php?rid=2615587&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%3D19607895%26dopt%3DAbstract Authors: Mulders WH, Paolini AG, Needham K, Robertson D The action of olivocochlear collaterals to the cochlear nucleus is not fully established. Synaptic ultrastructure suggests an excitatory role. Extracellular recordings show spikes evoked by electrical stimulation of olivocochlear axons, but these spikes in the cochlear nucleus may be antidromic (activation of output axons) or orthodromic (synaptic input). We therefore recorded intracellular responses to shocks to olivocochlear axons in anaesthetized guinea pigs. In chopper and primary-like neurons shocks caused either no response, or an inhibitory synaptic response (IPSP), but never an excitatory one (EPSP). In contrast, onset neurons never showed IPSPs but showed a variety of other responses; antidromic spikes, EPSPs, orthodromic... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2615587 Sun, 12 Jul 2009 23:00:00 +0100 2615587 http://www.medworm.com/index.php?rid=2615586&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%3D19607896%26dopt%3DAbstract Authors: Ealy M, Smith RJ Otosclerosis is a common form of conductive hearing loss with a prevalence of 0.3 to 0.4% in white adults. It is characterized by labyrinthine endochondral sclerosis which may invade the stapedio-vestibular joint and interfere with free motion of the stapes. Both environmental factors and genetic causes have been implicated in the disease process; however the pathogenesis of otosclerosis still remains poorly understood. To date, several loci have been mapped in families segregating autosomal dominant otosclerosis although no disease-causing mutations have been identified. In contrast, several association studies have implicated specific genes but their effects on risk-of-disease are small. The goal of this paper is to review the genetics of otosclerosis and to... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2615586 Sun, 12 Jul 2009 23:00:00 +0100 2615586 http://www.medworm.com/index.php?rid=2603150&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%3D19595753%26dopt%3DAbstract Authors: Luo X, Fu QJ, Wu HP, Hsu CJ In Mandarin Chinese, tonal patterns are lexically meaningful. In a multi-talker environment, competing tones may create interference in addition to competing vowels and consonants. The present study measured Mandarin-speaking cochlear implant (CI) users' ability to recognize concurrent vowels, tones, and syllables in a concurrent-syllable recognition test. Concurrent syllables were constructed by summing either one Chinese syllable each from one male and one female talker or two syllables from the same male talker. Each talker produced 16 different syllables (4 vowels combined with 4 tones); all syllables were normalized to have the same overall duration and amplitude. Both single- and concurrent-syllable recognition were measured in 4 adolescent an... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2603150 Wed, 08 Jul 2009 23:00:00 +0100 2603150 http://www.medworm.com/index.php?rid=2603149&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%3D19595754%26dopt%3DAbstract Authors: Bizley JK, King AJ Multisensory neurons are now known to be widespread in low-level regions of the cortex usually thought of as being responsible for modality-specific processing. The auditory cortex provides a particularly striking example of this, exhibiting responses to both visual and somatosensory stimulation. Single-neuron recording studies in ferrets have shown that each of auditory fields that have been characterized using physiological and anatomical criteria also receives visual inputs, with the incidence of visually-sensitive neurons ranging from 15-20% in the primary areas to around 50% or more in higher-level areas. Although some neurons exhibit spiking responses to visual stimulation, these inputs often have subthreshold influences that modulate the responses of ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2603149 Wed, 08 Jul 2009 23:00:00 +0100 2603149 http://www.medworm.com/index.php?rid=2603148&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%3D19595755%26dopt%3DAbstract Authors: Musacchia G, Schroeder CE Most auditory events in nature are accompanied by non-auditory signals, such as a view of the speaker's face during face-to-face communication or the vibration of a string during a musical performance. While it is known that accompanying visual and somatosensory signals can benefit auditory perception, often by making the sound seem louder, the specific neural bases for sensory amplification are still debated. In this review, we want to deal with what we regard as confusion on two topics that are crucial to our understanding of multisensory integration mechanisms in auditory cortex: 1) Anatomical Underpinnings (e.g. what circuits underlie multisensory convergence), and 2) Temporal Dynamics (e.g. what time windows of integration are physiologically fea... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2603148 Wed, 08 Jul 2009 23:00:00 +0100 2603148 http://www.medworm.com/index.php?rid=2524742&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%3D19341786%26dopt%3DAbstract Authors: Verhey JL, Ernst SM The present study investigates whether the difference in comodulation masking release (CMR) for different modulator types is due to the different degrees of modulator regularity, as suggested in the literature, or results from different envelope distributions. Thresholds of a sinusoidal signal are measured in the presence of a noise masker which was either broadband or narrow band. A square-wave modulator with different degrees of regularity is used that preserves the envelope distribution. The measured CMR does not decrease as the regularity decreases. This finding argues against the hypothesis that the difference in CMR for different modulator types reported in the literature is due to differences in regularity. The data for the narrow-band conditions whi... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524742 Sat, 27 Jun 2009 10:44:08 +0100 2524742 http://www.medworm.com/index.php?rid=2524739&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%3D19345257%26dopt%3DAbstract Authors: Pienkowski M, Hagerman B The just-noticeable difference (DeltaI) in the intensity (I) of sound is typically reported to be a constant or a slightly decreasing ratio of the baseline intensity (known as Weber's law, and the "near-miss to Weber's law", respectively). However, in the relatively few studies on the intensity discrimination of very brief sounds, DeltaI/I is usually found to be non-monotonic, with poorest discrimination in the middle of the auditory dynamic range. Here, it is demonstrated that this "severe departure from Weber's law" or "mid-level hump" is not merely a phenomenon of short-duration sounds. In normal-hearing subjects (n=8), the near-miss to Weber's law that is observed with the discrimination of 300 ms-long, 4 kHz tones, gives way to a significant mid-l... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524739 Sat, 27 Jun 2009 10:44:03 +0100 2524739 http://www.medworm.com/index.php?rid=2524736&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%3D19364527%26dopt%3DAbstract Authors: Adjamian P, Sereda M, Hall DA In this review, we highlight the contribution of advances in human neuroimaging to the current understanding of central mechanisms underpinning tinnitus and explain how interpretations of neuroimaging data have been guided by animal models. The primary motivation for studying the neural substrates of tinnitus in humans has been to demonstrate objectively its representation in the central auditory system and to develop a better understanding of its diverse pathophysiology and of the functional interplay between sensory, cognitive and affective systems. The ultimate goal of neuroimaging is to identify subtypes of tinnitus in order to better inform treatment strategies. The three neural mechanisms considered in this review may provide a basis for TI ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524736 Sat, 27 Jun 2009 10:43:57 +0100 2524736 http://www.medworm.com/index.php?rid=2524732&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%3D19376215%26dopt%3DAbstract This study documents a gradient in expression of SOD2 by spiral ganglion cells in basal versus apical turn of cochlea that is consistent with differential vulnerability of high frequency hearing to free radical damage. Immunohistochemical methods were used to identify distribution of SOD2 in temporal bone sections from mice, rats, macaques, and humans. In mice and rats, both the proportion of SOD2 immunopositive type 1 spiral ganglion cells and the intensity of immunoreactivity were elevated near cochlear apex. In macaques and humans, the proportion of SO2 immunopositive spiral ganglion cells was equal across cochlear turn, but the intensity of immunoreactivity remained highest for ganglion cells near cochlear apex. Strong SOD2 immunoreactivity was also observed in human type 1 spiral gang... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524732 Sat, 27 Jun 2009 10:43:47 +0100 2524732 http://www.medworm.com/index.php?rid=2524510&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%3D19545617%26dopt%3DAbstract Authors: Lanting CP, de Kleine E, van Dijk P Tinnitus is the percept of sound that is not related to an acoustic source outside the body. For many forms of tinnitus, mechanisms in the central nervous system are believed to play an important role in the pathology. Specifically, three mechanisms have been proposed to underlie tinnitus: (1) changes in the level of spontaneous neural activity in the central auditory system, (2) changes in the temporal pattern of neural activity, and (3) reorganization of tonotopic maps. The neuroimaging methods fMRI and PET measure signals that presumably reflect the firing rates of multiple neurons and are assumed to be sensitive to changes in the level of neural activity. There are two basic paradigms that have been applied in functional neuroimaging of ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524510 Thu, 18 Jun 2009 23:00:00 +0100 2524510 http://www.medworm.com/index.php?rid=2524511&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%3D19540324%26dopt%3DAbstract This study demonstrated that some proteins can be related to salicylate ototoxicity, and provides basic information about candidate proteins which are related to pathologic changes in salicylate-induced ototoxicity. PMID: 19540324 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524511 Tue, 16 Jun 2009 23:00:00 +0100 2524511 http://www.medworm.com/index.php?rid=2524512&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%3D19539739%26dopt%3DAbstract Conclusions Hearing protection is improved by increasing the time that dexamethasone is applied to the round window prior to cochlear implantation, and the waiting time can be reduced by increasing the steroid concentration. These results suggest that the diffusion dexamethasone through the cochlea is the prime determinant of the extent of hearing protection. PMID: 19539739 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524512 Mon, 15 Jun 2009 23:00:00 +0100 2524512 http://www.medworm.com/index.php?rid=2524516&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%3D19539016%26dopt%3DAbstract Authors: Apoux F, Healy EW The number of auditory filter outputs required to identify phonemes was estimated in two experiments. Stimuli were divided into 30 contiguous equivalent rectangular bandwidths (ERBN) spanning 80 to 7563 Hz. Normal-hearing listeners were presented with limited numbers of bands having frequency locations determined randomly from trial to trial to provide a general view, i.e., irrespective of specific band location, of the number of 1-ERBN-wide speech bands needed to identify phonemes. The first experiment demonstrated that 20 such bands are required to accurately identify vowels, and 16 are required to identify consonants. In the second experiment, speech-shaped noise or timereversed speech was introduced to the non-speech bands at various signal-to-noise ratio... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524516 Sun, 14 Jun 2009 23:00:00 +0100 2524516 http://www.medworm.com/index.php?rid=2524515&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%3D19539017%26dopt%3DAbstract Authors: Manley GA Lizard families can be grouped into larger units comprising those families that are closely related and whose auditory papillae are morphologically very similar. Based on the few species studied at that time (Manley, 1997), it was suggested that SOAE spectral patterns are strongly influenced by papillar anatomy. However, in two family groups, only one single species has been studied and we have no data on the regularity of pattern within related lizard families. Within the group of skink-like lizards, whose papillae all have salletal tectorial structures, the only detailed SOAE studies so far were on the skink genus Tiliqua. To ascertain the similarity of SOAE in species from families related to the skinks, we have studied one species each from two families that are ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524515 Sun, 14 Jun 2009 23:00:00 +0100 2524515 http://www.medworm.com/index.php?rid=2524514&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%3D19539018%26dopt%3DAbstract Authors: Nava E, Bottari D, Bonfioli F, Beltrame MA, Pavani F We assessed sound localisation abilities of late-implanted adults fitted with a single cochlear implant (CI) and examined whether these abilities are affected by the duration of implant use. Ten prelingually and four postlingually deafened adults who received a unilateral CI were tested in a sound-source identification task. Above chance performance was observed in those prelingual CI recipients who had worn their implant for longer time (9 years on average), revealing some monaural sound localization abilities in this population but only after extensive CI use. On the contrary, the four postlingual recipients performed equal or better with respect to the best prelingual participants despite shorter experience with the monau... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524514 Sun, 14 Jun 2009 23:00:00 +0100 2524514 http://www.medworm.com/index.php?rid=2524513&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%3D19539019%26dopt%3DAbstract We examined clarin-1 expression in the immortomouse-derived hair cell line UB/OC-1. Only isoform 2 is expressed in UB/OC-1 at both mRNA and protein levels, suggesting this isoform is biologically relevant to hair cell function. The protein co-localizes with microtubules and post-transgolgi vesicles. The sub-cellular localization of clarin-1 in hair cells and photoreceptors suggests it functions at both the basal and apical poles of neurosensoriepithelia. PMID: 19539019 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524513 Sun, 14 Jun 2009 23:00:00 +0100 2524513 http://www.medworm.com/index.php?rid=2524519&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%3D19531376%26dopt%3DAbstract Authors: El-Badry MM, McFadden SL Auditory neuropathy is a hearing disorder characterized by normal function of outer hair cells, evidenced by intact cochlear microphonic (CM) potentials and otoacoustic emissions (OAEs), with absent or severely dys-synchronized auditory brainstem responses (ABRs). To determine if selective lesions of inner hair cells (IHCs) and auditory nerve fibers (ANFs) can account for these primary clinical features of auditory neuropathy, we measured physiological responses from chinchillas with large lesions of ANFs (about 85%) and IHCs (45% loss in the apical half of the cochlea; 73% in the basal half). Distortion product OAEs and CM potentials were significantly enhanced, whereas summating potentials and compound action potentials (CAPs) were significantly redu... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524519 Fri, 12 Jun 2009 23:00:00 +0100 2524519 http://www.medworm.com/index.php?rid=2524518&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%3D19531377%26dopt%3DAbstract Authors: Rhode WS, Roth GL, Recio A Much of what is known about how the cochlear nuclei participate in mammalian hearing comes from studies of non-primate mammalian species. To determine to what extent the cochlear nuclei of primates resemble those of other mammalian orders, we have recorded responses to sound in three primate species: marmosets, Cynomolgus macaques, and squirrel monkeys. These recordings show that the same types of temporal firing patterns are found in primates that have been described in other mammals. Responses to tones of neurons in the ventral cochlear nucleus have similar tuning, latencies, post-stimulus time and interspike interval histograms as those recorded in non-primate cochlear nucleus neurons. In the dorsal cochlear nucleus, too, responses were similar. F... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524518 Fri, 12 Jun 2009 23:00:00 +0100 2524518 http://www.medworm.com/index.php?rid=2524526&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%3D19500658%26dopt%3DAbstract We present results showing that the modulation of auditory cortex is most likely mediated by feedback from heteromodal areas in the superior temporal cortex, but direct influences from visual cortex are not excluded. The influence of script on speech sound processing occurs automatically and shows extended development during reading acquisition. This review concludes with suggestions to answer currently still open questions to get closer to understanding the neural basis of normal and impaired literacy. PMID: 19500658 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524526 Thu, 11 Jun 2009 23:00:00 +0100 2524526 http://www.medworm.com/index.php?rid=2524525&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%3D19520151%26dopt%3DAbstract Authors: Maier JX, Groh JM We use both vision and audition when localizing objects and events in our environment. However, these sensory systems receive spatial information in different coordinate systems: sounds are localized using inter-aural and spectral cues, yielding a head-centered representation of space, whereas the visual system uses an eye-centered representation of space, based on the site of activation on the retina. In addition, the visual system employs a place-coded, retinotopic map of space, whereas the auditory system's representational format is characterized by broad spatial tuning and a lack of topographical organization. A common view is that the brain needs to reconcile these differences in order to control behavior, such as orienting gaze to the location of a sou... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524525 Mon, 08 Jun 2009 23:00:00 +0100 2524525 http://www.medworm.com/index.php?rid=2524524&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%3D19523509%26dopt%3DAbstract In conclusion, it is shown that the technique can reliably and quickly separate the source components, making it an attractive paradigm for applications in basic research and clinical diagnosis. PMID: 19523509 [PubMed - as supplied by publisher] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524524 Mon, 08 Jun 2009 23:00:00 +0100 2524524 http://www.medworm.com/index.php?rid=2524527&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%3D19497356%26dopt%3DAbstract Authors: Pap P, Kőszeghy A, Szűcs G, Rusznák Z The involvement of astrocytes in the cholinergic modulation of the cochlear nucleus has been studied using primary astrocyte cultures prepared from this nucleus. The cells were loaded with the membrane permeable form of the fluorescent Ca(2+) indicator Fluo-4, and carbachol-induced Ca(2+) concentration increases were monitored using an imaging system. In the presence of cholinergic stimulation 36.3% of the cells produced Ca(2+) transients. The time course of the transients was variable; 45.0% of the responding cells showed only a rapid Ca(2+) concentration increase, while in 50.5% of the astrocytes the fast component was followed by a slow plateau phase. Using muscarine as well as general and more specific cholinergic anta... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524527 Mon, 01 Jun 2009 23:00:00 +0100 2524527 http://www.medworm.com/index.php?rid=2524735&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%3D19371774%26dopt%3DAbstract Authors: Miranda JA, Wilczynski W Reproductive hormones can modulate communication-evoked behavior by acting on neural systems associated with motivation; however, recent evidence suggests that modulation occurs at the sensory processing level as well. The anuran auditory midbrain processes communication stimuli, and is sensitive to steroid hormones. Using multiunit electrophysiology, we tested whether sex and circulating testosterone influence auditory sensitivity to pure tones and to the natural vocalization in the green treefrog, Hyla cinerea. Sex did not influence audiogram best frequencies although sexes did differ in the sensitivities at those frequencies with males more sensitive in the lower frequency range. Females were more sensitive than males in response to the natural voca... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524735 Sun, 31 May 2009 23:00:00 +0100 2524735 http://www.medworm.com/index.php?rid=2524726&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%3D19397967%26dopt%3DAbstract Authors: Noirot IC, Adler HJ, Cornil CA, Harada N, Dooling RJ, Balthazart J, Ball GF Sex differences in song behavior and in the neural system controlling song in songbirds are well documented but relatively little is known about sex differences in hearing. We recently demonstrated the existence of sex differences in auditory brainstem responses in a songbird species, the zebra finch (Taeniopygia guttata). Many sex differences are regulated by sex steroid hormone action either during ontogeny or in adulthood. As a first step to test the possible implication of sex steroids in the control of sex differences in the zebra finch auditory system, we evaluated via immunocytochemistry whether estrogens are produced and act in the zebra finch inner ear. Specifically we examined the distributio... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524726 Sun, 31 May 2009 23:00:00 +0100 2524726 http://www.medworm.com/index.php?rid=2524725&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%3D19401225%26dopt%3DAbstract Authors: Miranda JA, Liu RC There is a growing consensus that the auditory system is dynamic in its representation of behaviorally relevant sounds. The auditory cortex in particular seems to be an important locus for plasticity that may reflect the memory of such sounds, or functionally improve their processing. The mechanisms that underlie these changes may be either intrinsic because they depend on the receiver's physiological state, or extrinsic because they arise from the context in which behavioral relevance is gained. Research in a mouse model of acoustic communication between offspring and adult females offers the opportunity to explore both of these contributions to auditory cortical plasticity in a natural context. Recent works have found that after the vocalizations of infant... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524725 Sun, 31 May 2009 23:00:00 +0100 2524725 http://www.medworm.com/index.php?rid=2524705&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%3D19450430%26dopt%3DAbstract Authors: McCullar JS, Oesterle EC Estrogen signaling in auditory and vestibular sensory epithelia is a newly emerging focus propelled by the role of estrogen signaling in many other proliferative systems. Understanding the pathways with which estrogen interacts can provide a means to identify how estrogen may modulate proliferative signaling in inner ear sensory epithelia. Reviewed herein are two signaling families, EGF and TGFbeta. Both pathways are involved in regulating proliferation of supporting cells in mature vestibular sensory epithelia and have well characterized interactions with estrogen signaling in other systems. It is becoming increasingly clear that elucidating the complexity of signaling in regeneration will be necessary for development of therapeutics that can initiate... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524705 Sun, 31 May 2009 23:00:00 +0100 2524705 http://www.medworm.com/index.php?rid=2524536&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%3D19450435%26dopt%3DAbstract Authors: Charitidi K, Meltser I, Tahera Y, Canlon B Recently significant progress was made in understanding the mechanisms by which the two estrogen receptors (alpha and beta) are involved in different pathways of estrogen action in a wide variance of tissues. Divergent responses of cells and tissues to estrogens or their ligands have been attributed to various isoforms and signaling pathways of estrogen receptors. Both subtypes of estrogen receptors have been identified in the cochlea and there are indications that they have neuroprotective effects but there is still limited information on the role and specific mechanisms of these two receptors in the auditory system. This review will examine the molecular and functional actions of the two estrogen receptor subtypes, the pivotal role ... Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524536 Sun, 31 May 2009 23:00:00 +0100 2524536 http://www.medworm.com/index.php?rid=2524517&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%3D19531444%26dopt%3DAbstract Authors: Canlon B, Frisina RD PMID: 19531444 [PubMed - in process] (Source: Hearing Research) Hearing Research journals http://www.medworm.com/rss/comments.php?id=2524517 Sun, 31 May 2009 23:00:00 +0100 2524517