JARO - Journal of the Association for Research in Otolaryngology
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166 records returned
Phase-Locked Responses to Tones of Chinchilla Auditory Nerve Fibers: Implications for Apical Cochlear Mechanics
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Abstract Responses to tones with frequency ≤ 5 kHz were recorded from auditory nerve fibers (ANFs) of anesthetized chinchillas. With
increasing stimulus level, discharge rate–frequency functions shift toward higher and lower frequencies, respectively, for
ANFs with characteristic frequencies (CFs) lower and higher than ∼0.9 kHz. With increasing frequency separation from CF, rate–level
functions are less steep and/or saturate at lower rates than at CF, indicating a CF-specific nonlinearity. The strength of
phase locking has lower high-frequency cutoffs for CFs >4 kHz than for CFs...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 17, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Effects of Hearing Preservation on Psychophysical Responses to Cochlear Implant StimulationEmail this article to a colleague.
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Abstract Previous studies have shown that residual acoustic hearing supplements cochlear implant function to improve speech recognition
in noise as well as perception of music. The current study had two primary objectives. First, we sought to determine how cochlear
implantation and electrical stimulation over a time period of 14 to 21 months influence cochlear structures such as hair cells
and spiral ganglion neurons. Second, we sought to investigate whether the structures that provide acoustic hearing also affect
the perception of electrical stimulation. We compared psychophysical responses to cochlear...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 10, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Glycosylation Regulates Prestin Cellular ActivityEmail this article to a colleague.
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Abstract Glycosylation is a common post-translational modification of proteins and is implicated in a variety of cellular functions
including protein folding, degradation, sorting and trafficking, and membrane protein recycling. The membrane protein prestin
is an essential component of the membrane-based motor driving electromotility changes (electromotility) in the outer hair
cell (OHC), a central process in auditory transduction. Prestin was earlier identified to possess two N-glycosylation sites
(N163, N166) that, when mutated, marginally affect prestin nonlinear capacitance (NLC) function in cultured cel...
Source: JARO - Journal of the Association for Research in Otolaryngology - November 7, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Tympanic Membrane Boundary Deformations Derived from Static Displacements Observed with Computerized Tomography in Human and GerbilEmail this article to a colleague.
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Abstract The middle ear is too complex a system for its function to be fully understood with simple descriptive models. Realistic mathematical
models must be used in which structural elements are represented by geometrically correct three-dimensional (3D) models with
correct physical parameters and boundary conditions. In the past, the choice of boundary conditions could not be based on
experimental evidence as no clear-cut data were available. We have, therefore, studied the deformation of the tympanic membrane
(TM) at its boundaries using X-ray microscopic computed tomography in human and gerbil while stat...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 16, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
A Quantitative Analysis of the Spatiotemporal Pattern of Transient Receptor Potential Gene Expression in the Developing Mouse CochleaEmail this article to a colleague.
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Abstract TRP genes encode a diverse family of ion channels which have been implicated in many sensory functions. Because several TRP
channels have similar properties to the elusive hair cell transduction channel, recent attention has focused on TRP gene expression
in the inner ear. At least four TRP genes are known to be expressed in hair cells: TRPC3, TRPV4, TRPA1, and TRPML3. However,
there is little evidence supporting any of these as a component of the transduction complex. Other less well-characterized
TRP channels are expressed in the inner ear, in particular, within the organ of Corti. Because of thei...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 16, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Simultaneous Grouping in Cochlear Implant Listeners: Can Abrupt Changes in Level Be Used to Segregate Components from a Complex Tone?Email this article to a colleague.
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Abstract A sudden increase in the amplitude of a component often causes its segregation from a complex tone, and shorter rise times
enhance this effect. We explored whether this also occurs in implant listeners (n = 8). Condition 1 used a 3.5-s “complex tone” comprising concurrent stimulation on five electrodes distributed across the
array of the Nucleus CI24 implant. For each listener, the baseline stimulus level on each electrode was set at 50% of the
dynamic range (DR). Two 1-s increments of 12.5%, 25%, or 50% DR were introduced in succession on adjacent electrodes within
the “inner” thre...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 14, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Cell-Specific Inducible Gene Recombination in Postnatal Inner Ear Supporting Cells and GliaEmail this article to a colleague.
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Abstract Recent studies indicate that supporting cells play important roles in inner ear development, function, and regeneration after
injury, but the molecular mechanisms underlying these processes remain poorly understood. Inducible cell-specific gene recombination
in supporting cells could be a powerful tool to study the roles of specific molecules in these cells. Here we tested the feasibility,
effectiveness, and cell specificity of inducible Cre-mediated gene recombination in the postnatal inner ear using mice that
express an inducible form of Cre (CreERT) under the transcriptional control of the proteo...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 10, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Amplitude Modulation and Loudness in Cochlear ImplanteesEmail this article to a colleague.
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Abstract The effect of amplitude modulation of pulse trains on the loudness perceived by cochlear implantees was investigated for different
overall levels of the signal, modulation depth and the carrier rate of the pulse train. Equally loud and threshold levels
were determined for a variety of signal levels, modulation depths and carrier rates in six cochlear implantees. The pattern
of results was consistent with the predictions of a previously published loudness model of McKay et al. (J Acoust Soc Am 113:2054–2063,
2003). The degree to which the loudness of modulated stimuli differed from the loudness eli...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 2, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
The Effect of Contralateral Acoustic Stimulation on Spontaneous Otoacoustic EmissionsEmail this article to a colleague.
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Abstract Evoked otoacoustic emissions are often used to study the medial olivocochlear (MOC) efferents in humans. There has been concern
that the emission-evoking stimulus may itself elicit efferent activity and alter the evoked otoacoustic emission. Spontaneous
otoacoustic emissions (SOAEs) are hence advantageous as no external stimulation is necessary to record the response in the
test ear. Contralateral acoustic stimulation (CAS) has been shown to suppress SOAE level and elevate SOAE frequency, but the
time course of these effects is largely unknown. By utilizing the Choi–Williams distribution, here we ...
Source: JARO - Journal of the Association for Research in Otolaryngology - October 2, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
A Model of Incomplete Adaptation to a Severely Shifted Frequency-to-Electrode Mapping by Cochlear Implant UsersEmail this article to a colleague.
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Abstract In the present study, a computational model of phoneme identification was applied to data from a previous study, wherein cochlear
implant (CI) users’ adaption to a severely shifted frequency allocation map was assessed regularly over 3 months of continual
use. This map provided more input filters below 1 kHz, but at the expense of introducing a downwards frequency shift of up
to one octave in relation to the CI subjects’ clinical maps. At the end of the 3-month study period, it was unclear whether
subjects’ asymptotic speech recognition performance represented a complete or partial a...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 23, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Comodulation Masking Release Determined in the Mouse (Mus musculus) using a Flanking-band ParadigmEmail this article to a colleague.
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Abstract Comodulation masking release (CMR) has been attributed to auditory processing within one auditory channel (within-channel
cues) and/or across several auditory channels (across-channel cues). The present flanking-band (FB) experiment—using a 25-Hz-wide
on-frequency noise masker (OFM) centered at the signal frequency of 10 kHz and a single 25-Hz-wide noise FB—was designed to
separate the amount of CMR due to within- and across-channel cues and to investigate the role of temporal cues on the size
of within-channel CMR. The results demonstrated within-channel CMR in the Naval Medical Research I...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 17, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Interaural Correlation Fails to Account for Detection in a Classic Binaural Task: Dynamic ITDs Dominate N0Sπ DetectionEmail this article to a colleague.
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Abstract Binaural signal detection in an NoSπ task relies on interaural disparities introduced by adding an antiphasic signal to diotic
noise. What metric of interaural disparity best predicts performance? Some models use interaural correlation; others differentiate
between dynamic interaural time differences (ITDs) and interaural level differences (ILDs) of the effective stimulus. To examine
the relative contributions of ITDs and ILDs in binaural detection, we developed a novel signal processing technique that selectively
degrades different aspects (potential cues) of binaural stimuli (e.g., only ITDs are ...
Source: JARO - Journal of the Association for Research in Otolaryngology - September 17, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Discrimination of Time-Reversed Harmonic Complexes by Normal-Hearing and Hearing-Impaired ListenersEmail this article to a colleague.
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Abstract Normal-hearing (NH) listeners and hearing-impaired (HI) listeners detected and discriminated time-reversed harmonic complexes
constructed of equal-amplitude harmonic components with fundamental frequencies (F0s) ranging from 50 to 800 Hz. Component
starting phases were selected according to the positive and negative Schroeder-phase algorithms to produce within-period frequency
sweeps with relatively flat temporal envelopes. Detection thresholds were not affected by component starting phases for either
group of listeners. At presentation levels of 80 dB SPL, NH listeners could discriminate ...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 25, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Anatomy of the Distal Incus in HumansEmail this article to a colleague.
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Abstract The anatomy of the distal incus, including the lenticular process, was examined in histological sections from 270 normal cadaveric
human temporal bones aged between less than 1 month and 100 years. All but nine of these sectioned specimens showed signs
of a bony connection between the long process of the incus and the flattened plate of the lenticular process, and in 108 specimens
a complete bony attachment was observed in a single 20 μm section. In these 108 ears, the bony lenticular process consisted
of a proximal narrow “pedicle” connected to a distal flattened “plate” tha...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 15, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Auditory Cortical Activity During Cochlear Implant-Mediated Perception of Spoken Language, Melody, and RhythmEmail this article to a colleague.
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Abstract Despite the significant advances in language perception for cochlear implant (CI) recipients, music perception continues to
be a major challenge for implant-mediated listening. Our understanding of the neural mechanisms that underlie successful implant
listening remains limited. To our knowledge, this study represents the first neuroimaging investigation of music perception
in CI users, with the hypothesis that CI subjects would demonstrate greater auditory cortical activation than normal hearing
controls. H2
15O positron emission tomography (PET) was used here to assess auditory cortical activatio...
Source: JARO - Journal of the Association for Research in Otolaryngology - August 7, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Supporting Cell Characteristics in Long-deafened Aged Mouse EarsEmail this article to a colleague.
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We examined the expression
of several known support cell markers to investigate for possible support cell dedifferentiation in the damaged ears. The
support cell markers investigated included the microtubule protein acetylated tubulin, the transcription factor Sox2, and
the Notch signaling ligand Jagged1. Non-sensory epithelial cells remaining in the organ of Corti retain acetylated tubulin,
Sox2 and Jagged1 expression, even when the epithelium has a monolayer-like appearance. These results suggest a lack of marked
SC dedifferentiation in these aged and badly damaged ears.
Content Type Journal ArticleDOI 10.1007/s1...
Source: JARO - Journal of the Association for Research in Otolaryngology - July 31, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Abnormal Cochlear Potentials from Deaf Patients with Mutations in the Otoferlin GeneEmail this article to a colleague.
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Abstract Otoferlin is involved in neurotransmitter release at the synapse between inner hair cells (IHCs) and auditory nerve fibres,
and mutations in the OTOF gene result in severe to profound hearing loss. Abnormal sound-evoked cochlear potentials were recorded with transtympanic
electrocochleography from four children with otoferlin (OTOF) mutations to evaluate physiological effects in humans of abnormal neurotransmitter release from IHCs. The subjects were
profoundly deaf with absent auditory brainstem responses and preserved otoacoustic emissions consistent with auditory neuropathy.
Two children were com...
Source: JARO - Journal of the Association for Research in Otolaryngology - July 28, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
On- and Off-Frequency Forward Masking by Schroeder-Phase ComplexesEmail this article to a colleague.
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Abstract Forward masking by harmonic tone complexes was measured for on- and off-frequency maskers as a function of masker phase curvature
for two masker durations (30 and 200 ms). For the lowest signal frequency (1 kHz), the results matched predictions based on
the expected interactions between the phase curvature and amplitude compression of peripheral auditory filtering. For the
higher signal frequencies (2 and 6 kHz), the data increasingly departed from predictions in two respects. First, the effects
of the masker phase curvature became stronger with increasing masker duration, inconsisten...
Source: JARO - Journal of the Association for Research in Otolaryngology - July 24, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Acoustic Clicks Activate both the Canal and Otolith Vestibulo-Ocular Reflex Pathways in Behaving MonkeysEmail this article to a colleague.
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Abstract Acoustic activation of the vestibular system has been well documented in humans and animal models. In the past decade, sound-evoked
myogenic potentials in the sternocleidomastoid muscle (cVEMP) and the extraocular muscles (oVEMP) have been extensively studied,
and their potentials as new tests for vestibular function have been widely recognized. However, the extent to which sound
activates the otolith and canal pathways remains controversial. In the present study, we examined this issue in a recently
developed nonhuman primate model of acoustic activation of the vestibular system, i.e., sound-evoked...
Source: JARO - Journal of the Association for Research in Otolaryngology - July 24, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Otoacoustic Emission Theories and Behavioral Estimates of Human Basilar Membrane Motion Are Mutually ConsistentEmail this article to a colleague.
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Abstract When two pure tones (or primaries) of slightly different frequencies (f
1 and f
2) are presented to the ear, new frequency components are generated by nonlinear interaction of the primaries within the cochlea.
These new components can be recorded in the ear canal as otoacoustic emissions (OAE). The level of the 2f
1−f
2 OAE component is known as the distortion product otoacoustic emission (DPOAE) and is regarded as an indicator of the physiological
state of the cochlea. The current view is that maximal level DPOAEs occur for primaries that produce equal excitation at the
f
2 cochlear region, b...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 13, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Lipid Lateral Mobility in Cochlear Outer Hair Cells: Regional Differences and Regulation by CholesterolEmail this article to a colleague.
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Abstract The outer hair cell (OHC) lateral plasma membrane houses the transmembrane protein prestin, a necessary component of the yet
unknown molecular mechanism(s) underlying electromotility and the exquisite sensitivity and frequency selectivity of mammalian
hearing. The importance of the plasma membrane environment in modulating OHC electromotility has been substantiated by recent
studies demonstrating that membrane cholesterol alters prestin activity in a manner consistent with cholesterol-induced changes
in auditory function. Cholesterol is known to affect membrane material properties, and measurements ...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 11, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Dynamic Displacement of Normal and Detached Semicircular Canal CupulaEmail this article to a colleague.
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Abstract The dynamic displacement of the semicircular canal cupula and modulation of afferent nerve discharge were measured simultaneously
in response to physiological stimuli in vivo. The adaptation time constant(s) of normal cupulae in response to step stimuli
averaged 36 s, corresponding to a mechanical lower corner frequency for sinusoidal stimuli of 0.0044 Hz. For stimuli equivalent
to 40–200 deg/s of angular head velocity, the displacement gain of the central region of the cupula averaged 53 nm per deg/s.
Afferents adapted more rapidly than the cupula, demonstrating the presence o...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 10, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Interaural Time-Delay Sensitivity in Bilateral Cochlear Implant Users: Effects of Pulse Rate, Modulation Rate, and Place of StimulationEmail this article to a colleague.
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Abstract Electrical interaural time delay (ITD) discrimination was measured using 300-ms bursts applied to binaural pitch matched electrodes
at basal, mid, and apical locations in each ear. Six bilateral implant users, who had previously shown good ITD sensitivity
at a pulse rate of 100 pulses per second (pps), were assessed. Thresholds were measured as a function of pulse rate between
100 and 1,000 Hz, as well as modulation rate over that same range for high-rate pulse trains at 6,000 pps. Results were similar
for all three places of stimulation and showed decreasing ITD sensitivity as either puls...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 10, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Processing Temporal Modulations in Binaural and Monaural Auditory Stimuli by Neurons in the Inferior Colliculus and Auditory CortexEmail this article to a colleague.
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Abstract Processing dynamic changes in the stimulus stream is a major task for sensory systems. In the auditory system, an increase
in the temporal integration window between the inferior colliculus (IC) and auditory cortex is well known for monaural signals
such as amplitude modulation, but a similar increase with binaural signals has not been demonstrated. To examine the limits
of binaural temporal processing at these brain levels, we used the binaural beat stimulus, which causes a fluctuating interaural
phase difference, while recording from neurons in the unanesthetized rabbit. We found that the cutoff f...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 9, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Basilar Membrane Responses to Noise at a Basal Site of the Chinchilla Cochlea: Quasi-Linear FilteringEmail this article to a colleague.
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Abstract Basilar membrane responses to clicks and to white noise were recorded using laser velocimetry at basal sites of the chinchilla
cochlea with characteristic frequencies near 10 kHz. Responses to noise grew at compressive rates and their instantaneous
frequencies decreased with increasing stimulus level. First-order Wiener kernels were computed by cross-correlation of the
noise stimuli and the responses. For linear systems, first-order Wiener kernels are identical to unit impulse responses. In
the case of basilar membrane responses, first-order Wiener kernels and responses to clicks measured at th...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 4, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Spatial and Temporal Effects of Interleaved Masking in Cochlear ImplantsEmail this article to a colleague.
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Abstract Modern cochlear implants utilize interleaved presentation of pulses on different electrodes to avoid physical interference
among multiple current fields, yet neural interaction still exists. In the present study, masking was examined with four Nucleus24
users with the banded electrode array in an interleaved masking paradigm, where a probe stimulus was interleaved with a masker
stimulus. Spatial and temporal aspects of masking were addressed by fixing the masker at the middle of the electrode array
and changing the location of the probe and by testing various stimulation rates: 125, 500, 2,000, and ...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 4, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Tuning of the Tectorial Membrane in the Basilar Papilla of the Northern Leopard FrogEmail this article to a colleague.
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Abstract The basilar papilla (BP) in the frog inner ear is a relatively simple auditory receptor. Its hair cells are embedded in a
stiff support structure, with the stereovilli connecting to a flexible tectorial membrane (TM). Acoustic energy passing the
papilla presumably causes displacement of the TM, which in turn deflects the stereovilli and stimulates the hair cells. Auditory
neurons that contact the BP’s hair cells are known to have nearly identical characteristic frequencies and frequency selectivity.
In this paper, we present optical measurements of the mechanical response of the TM. Results were o...
Source: JARO - Journal of the Association for Research in Otolaryngology - June 2, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Constitutive Expression of the α10 Nicotinic Acetylcholine Receptor Subunit Fails to Maintain Cholinergic Responses in Inner Hair Cells After the Onset of HearingEmail this article to a colleague.
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Abstract Efferent inhibition of cochlear hair cells is mediated by α9α10 nicotinic cholinergic receptors (nAChRs) functionally coupled
to calcium-activated, small conductance (SK2) potassium channels. Before the onset of hearing, efferent fibers transiently
make functional cholinergic synapses with inner hair cells (IHCs). The retraction of these fibers after the onset of hearing
correlates with the cessation of transcription of the Chrna10 (but not the Chrna9) gene in IHCs. To further analyze this developmental change, we generated a transgenic mice whose IHCs constitutively express
α10 into adulthood by...
Source: JARO - Journal of the Association for Research in Otolaryngology - May 19, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Hes5 Expression in the Postnatal and Adult Mouse Inner Ear and the Drug-Damaged CochleaEmail this article to a colleague.
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In this study, we use Hes5-GFP transgenic mice and
in situ hybridization to report the expression pattern of Hes5 in the inner ear. We find that Hes5 is expressed in the developing auditory epithelium of the cochlea beginning at embryonic day 14.5 (E14.5), becomes restricted
to a particular subset of cochlear supporting cells, is downregulated in the postnatal cochlea, and is not present in adults.
In the vestibular system, we detect Hes5 in developing supporting cells as early as E12.5 and find that Hes5 expression is maintained in some adult vestibular supporting cells. In order to determine the effect of hair ce...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 17, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Quantifying Envelope and Fine-Structure Coding in Auditory Nerve Responses to Chimaeric SpeechEmail this article to a colleague.
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Abstract Any sound can be separated mathematically into a slowly varying envelope and rapidly varying fine-structure component. This
property has motivated numerous perceptual studies to understand the relative importance of each component for speech and
music perception. Specialized acoustic stimuli, such as auditory chimaeras with the envelope of one sound and fine structure
of another have been used to separate the perceptual roles for envelope and fine structure. Cochlear narrowband filtering
limits the ability to isolate fine structure from envelope; however, envelope recovery from fine structure has be...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 14, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Enhanced Survival of Spiral Ganglion Cells After Cessation of Treatment with Brain-Derived Neurotrophic Factor in Deafened Guinea PigsEmail this article to a colleague.
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In this study, the survival and functionality
of SGCs were investigated after temporary treatment with brain-derived neurotrophic factor (BDNF). Guinea pigs in the experimental
group were deafened, and 2 weeks later, the right cochleae were implanted with an electrode array and drug delivery cannula.
BDNF was administered to the implanted cochleae during a 4-week period via a mini-osmotic pump. After completion of the treatment,
the osmotic pumps were removed. Two weeks later, the animals were killed and the survival of SGCs was analyzed. To monitor
the functionality of the auditory nerve, electrically evoked aud...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 14, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Epigenetic Influences on Sensory Regeneration: Histone Deacetylases Regulate Supporting Cell Proliferation in the Avian UtricleEmail this article to a colleague.
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This study examined effects of histone deacetylases (HDACs), whose main function is to modify histone acetylation,
on the regulation of regenerative proliferation in the chick utricle. Cultures of regenerating utricles and dissociated cells
from the utricular sensory epithelia were treated with the HDAC inhibitors valproic acid, trichostatin A, sodium butyrate,
and MS-275. All of these molecules prevent the enzymatic removal of acetyl groups from histones, thus maintaining nuclear
chromatin in a “relaxed” (open) configuration. Treatment with all inhibitors resulted in comparable decreases in supporting
cell prolif...
Source: JARO - Journal of the Association for Research in Otolaryngology - April 2, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Dynamical Instability Determines the Effect of Ongoing Noise on Neural FiringEmail this article to a colleague.
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Abstract At low stimulation rates, electrically stimulated auditory nerve fibers typically fire regularly, in lock-step to the applied
stimulus. At high stimulation rates, however, these same fibers fire irregularly. Firing irregularity has been attributed
to the random opening and closing of voltage-gated sodium channels at the spike generation site. We demonstrate, however,
that the nonlinear dynamics of neural excitation and refractoriness embodied in the FitzHugh–Nagumo (FN) model produce realistic
firing irregularity at high stimulus rates, even in the complete absence of ongoing physiological noise. ...
Source: JARO - Journal of the Association for Research in Otolaryngology - March 24, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Immunocytochemical Traits of Type IV Fibrocytes and Their Possible Relations to Cochlear Function and PathologyEmail this article to a colleague.
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This report presents an animal model for type IV fibrocyte loss, along with immunocytochemical evidence
that noise-induced loss of these cells may account for previously unexplained hearing losses. The remarkably low threshold
for noise-induced loss of type IV fibrocytes, approximately 24 dB less than the threshold for adjacent hair cell destruction,
may account for the prevalence of missing fibrocytes in humans. In mice, changes in the spectrum of traumatizing noise had
little effect upon the site of loss of the fibrocytes, suggesting that the primary site of damage that induced the loss was
the basal-most cochl...
Source: JARO - Journal of the Association for Research in Otolaryngology - March 11, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Electrophysiological Properties of Octopus Neurons of the Cat Cochlear Nucleus: an In Vitro StudyEmail this article to a colleague.
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In conclusion, the similarity of octopus cells in mice and kittens suggests that the anatomical and biophysical specializations
that allow octopus cells to detect and convey synchronous firing among auditory nerve fibers are common to all mammals.
Content Type Journal ArticleDOI 10.1007/s10162-009-0159-xAuthors
Ramazan Bal, Firat University Department of Biophysics, Faculty of Medicine 23119 Elazig TurkeyGiyasettin Baydas, Firat University Department of Physiology, Faculty of Medicine Elazig Turkey
Journal JARO - Journal of the Association for Research in OtolaryngologyOnline ISSN 1438-7573Print ISSN 1525-3961...
Source: JARO - Journal of the Association for Research in Otolaryngology - March 11, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Human Medial Olivocochlear Reflex: Effects as Functions of Contralateral, Ipsilateral, and Bilateral Elicitor BandwidthsEmail this article to a colleague.
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Abstract Animal studies have led to the view that the acoustic medial olivocochlear (MOC) efferent reflex provides sharply tuned frequency-specific
feedback that inhibits cochlear amplification. To determine if MOC activation is indeed narrow band, we measured the MOC effects
in humans elicited by 60-dB sound pressure level (SPL) contralateral, ipsilateral, and bilateral noise bands as a function
of noise bandwidth from 1/2 to 6.7 octaves. MOC effects were quantified by the change in stimulus frequency otoacoustic emissions
from 40 dB SPL probe tones near 0.5, 1, and 4 kHz. In a second experiment, ...
Source: JARO - Journal of the Association for Research in Otolaryngology - March 5, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Trafficking of Systemic Fluorescent Gentamicin into the Cochlea and Hair CellsEmail this article to a colleague.
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Abstract Aminoglycosides enter inner ear hair cells across their apical membranes via endocytosis, or through the mechanoelectrical
transduction channels in vitro, suggesting that these drugs enter cochlear hair cells from endolymph to exert their cytotoxic
effect. We used zebrafish to determine if fluorescently tagged gentamicin (GTTR) also enters hair cells via apically located
calcium-sensitive cation channels and the cytotoxicity of GTTR to hair cells. We then examined the serum kinetics of GTTR
following systemic injection in mice and which murine cochlear sites preferentially loaded with systemically a...
Source: JARO - Journal of the Association for Research in Otolaryngology - March 3, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Electrical Properties and Functional Expression of Ionic Channels in Cochlear Inner Hair Cells of Mice Lacking the α10 Nicotinic Cholinergic Receptor SubunitEmail this article to a colleague.
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Abstract Cochlear inner hair cells (IHCs) release neurotransmitter onto afferent auditory nerve fibers in response to sound stimulation.
During early development, synaptic transmission is triggered by spontaneous Ca2+ spikes which are modulated by an efferent cholinergic innervation to IHCs. This synapse is inhibitory and mediated by the
α9α10 nicotinic cholinergic receptor (nAChR). After the onset of hearing, large-conductance Ca2+-activated K+ channels are acquired and both the spiking activity and the efferent innervation disappear from IHCs. In this work, we studied
the developmental changes in the memb...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 28, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Stem/Progenitor Cells Derived from the Cochlear Sensory Epithelium Give Rise to Spheres with Distinct Morphologies and FeaturesEmail this article to a colleague.
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Abstract Nonmammalian vertebrates regenerate lost sensory hair cells by means of asymmetric division of supporting cells. Inner ear
or lateral line supporting cells in birds, amphibians, and fish consequently serve as bona fide stem cells resulting in high
regenerative capacity of hair cell-bearing organs. Hair cell regeneration does not happen in the mammalian cochlea, but cells
with proliferative capacity can be isolated from the neonatal cochlea. These cells have the ability to form clonal floating
colonies, so-called spheres, when cultured in nonadherent conditions. We noticed that the sphere population ...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 27, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Identification of FDA-Approved Drugs and Bioactives that Protect Hair Cells in the Zebrafish (
Danio rerio
) Lateral Line and Mouse (
Mus musculus
) UtricleEmail this article to a colleague.
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Abstract The hair cells of the larval zebrafish lateral line provide a useful preparation in which to study hair cell death and to
screen for genes and small molecules that modulate hair cell toxicity. We recently reported preliminary results from screening
a small-molecule library for compounds that inhibit aminoglycoside-induced hair cell death. To potentially reduce the time
required for development of drugs and drug combinations that can be clinically useful, we screened a library of 1,040 FDA-approved
drugs and bioactive compounds (NINDS Custom Collection II). Seven compounds that protect against neomyc...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 25, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
A Mouse Model for Degeneration of the Spiral LigamentEmail this article to a colleague.
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Abstract Previous studies have indicated the importance of the spiral ligament (SL) in the pathogenesis of sensorineural hearing loss.
The aim of this study was to establish a mouse model for SL degeneration as the basis for the development of new strategies
for SL regeneration. We injected 3-nitropropionic acid (3-NP), an inhibitor of succinate dehydrogenase, at various concentrations
into the posterior semicircular canal of adult C57BL/6 mice. Saline-injected animals were used as controls. Auditory function
was monitored by measurements of auditory brain stem responses (ABRs). On postoperative day 14,...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 12, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Auditory Nerve Fiber Responses to Combined Acoustic and Electric StimulationEmail this article to a colleague.
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Abstract Persons with a prosthesis implanted in a cochlea with residual acoustic sensitivity can, in some cases, achieve better speech
perception with “hybrid” stimulation than with either acoustic or electric stimulation presented alone. Such improvements
may involve “across auditory-nerve fiber” processes within central nuclei of the auditory system and within-fiber interactions
at the level of the auditory nerve. Our study explored acoustic–electric interactions within feline auditory nerve fibers
(ANFs) so as to address two goals. First, we sought to better understand recent results that showed...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 11, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Loudness Perception in the Domestic Cat: Reaction Time Estimates of Equal Loudness Contours and Recruitment EffectsEmail this article to a colleague.
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This study used a reaction time task to characterize loudness perception
in six behaviorally trained cats. The psychophysical approach was based on the assumption that sounds of equal loudness elicit
responses of equal latency. The resulting equal latency contours reproduced well-known features of human equal loudness contours.
At the completion of normal baseline measures, the cats were exposed to intense sound to investigate the behavioral correlates
of loudness recruitment, the abnormally rapid growth of loudness that is commonly associated with hearing loss. Observed recruitment
effects were similar in magnitude t...
Source: JARO - Journal of the Association for Research in Otolaryngology - February 7, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Commissural Neurons in the Rat Ventral Cochlear NucleusEmail this article to a colleague.
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Abstract Commissural neurons connect the cochlear nucleus complexes of both ears. Previous studies have suggested that the neurons
may be separated into two anatomical subtypes on the basis of percent apposition (PA); that is, the percentage of the soma
apposed by synaptic terminals. The present study combined tract tracing with synaptic immunolabeling to compare the soma area,
relative number, and location of Type I (low PA) and Type II (high PA) commissural neurons in the ventral cochlear nucleus
(VCN) of rats. Confocal microscopic analysis revealed that 261 of 377 (69%) commissural neurons have medium-siz...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 27, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Recruitment of Neurons and LoudnessEmail this article to a colleague.
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Content Type Journal ArticleCategory CommentaryDOI 10.1007/s10162-009-0156-0Authors
Philip X. Joris, University of Leuven Laboratory of Auditory Neurophysiology Campus Gasthuisberg O/N2, Herestraat 49 bus 1021 B-3000 Leuven Belgium
Journal JARO - Journal of the Association for Research in OtolaryngologyOnline ISSN 1438-7573Print ISSN 1525-3961 (Source: JARO - Journal of the Association for Research in Otolaryngology)
Source: JARO - Journal of the Association for Research in Otolaryngology - January 22, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Lipopolysaccharide-Induced Osteoclastogenesis from Mononuclear Precursors: A Mechanism for Osteolysis in Chronic OtitisEmail this article to a colleague.
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In this study, we examined the mechanisms
by which P. aeruginosa lipopolysaccharide (LPS) stimulates osteoclastogenesis directly from mononuclear osteoclast precursor cells. Osteoclast precursors
demonstrated robust, bone-resorbing osteoclast formation when stimulated by P. aeruginosa LPS only if previously primed with permissive, sub-osteoclastogenic doses of receptor activator of NF-κB ligand (RANKL),
suggesting that LPS is osteoclastogenic only during a specific developmental window. Numerous LPS-elicited cytokines were
found to be released by osteoclast precursors undergoing P. aeruginosa LPS-mediated osteoclast f...
Source: JARO - Journal of the Association for Research in Otolaryngology - January 15, 2009 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Variation in the Phase of Response to Low-Frequency Pure Tones in the Guinea Pig Auditory Nerve as Functions of Stimulus Level and FrequencyEmail this article to a colleague.
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Abstract The directionality of hair cell stimulation combined with the vibration of the basilar membrane causes the auditory nerve
fiber action potentials, in response to low-frequency stimuli, to occur at a particular phase of the stimulus waveform. Because
direct mechanical measurements at the cochlear apex are difficult, such phase locking has often been used to indirectly infer
the basilar membrane motion. Here, we confirm and extend earlier data from mammals using sine wave stimulation over a wide
range of sound levels (up to 90 dB sound pressure level). We recorded phase-locked responses to pure t...
Source: JARO - Journal of the Association for Research in Otolaryngology - December 18, 2008 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Responses to Diotic, Dichotic, and Alternating Phase Harmonic Stimuli in the Inferior Colliculus of Guinea PigsEmail this article to a colleague.
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We examined both the temporal and rate-tuning of IC clusters
and found no evidence for binaural integration. Stimuli comprised all harmonics below 10 kHz with fundamental frequencies
(F0) from 50 to 400 Hz in half-octave steps. In diotic conditions, all the harmonics were presented to both ears. In dichotic
conditions, odd harmonics were presented to one ear and even harmonics to the other. Neural characteristic frequencies (CF,
n = 85) were from 0.2 to 14.7 kHz; 29 had CFs below 1 kHz. The majority of clusters responded predominantly to the contralateral
ear, with the dominance of the contrala...
Source: JARO - Journal of the Association for Research in Otolaryngology - December 17, 2008 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Distribution of the Na,K-ATPase α Subunit in the Rat Spiral Ganglion and Organ of CortiEmail this article to a colleague.
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Abstract Processing of sound in the cochlea involves both afferent and efferent innervation. The Na,K-ATPase (NKA) is essential for
cells that maintain hyperpolarized membrane potentials and sodium and potassium concentration gradients. Heterogeneity of
NKA subunit expression is one mechanism that tailors physiology to particular cellular demands. Therefore, to provide insight
into molecular differences that distinguish the various innervation pathways in the cochlea, we performed a variety of double
labeling experiments with antibodies against three of the α isoforms of the NKA (NKAα1–3) and markers ide...
Source: JARO - Journal of the Association for Research in Otolaryngology - December 12, 2008 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
Differential Intracochlear Sound Pressure Measurements in Normal Human Temporal BonesEmail this article to a colleague.
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We present the first simultaneous sound pressure measurements in scala vestibuli and scala tympani of the cochlea in human
cadaveric temporal bones. The technique we employ, which exploits microscale fiberoptic pressure sensors, enables the study
of differential sound pressure at the cochlear base. This differential pressure is the input to the cochlear partition, driving
cochlear waves and auditory transduction. In our results, the sound pressure in scala vestibuli (P
SV) was much greater than scala tympani pressure (P
ST), except for very low and high frequencies where P
ST significantly affected the input to the c...
Source: JARO - Journal of the Association for Research in Otolaryngology - December 10, 2008 Category: ENT & OMF Tags: JARO - Journal of the Association for Research in Otolaryngology Source Type: journals
