Acute high-intensity noise induces rapid Arc protein expression but fails to rapidly change GAD expression in amygdala and hippocampus of rats: Effects of treatment with D-cycloserine.
Abstract Tinnitus is a devastating auditory disorder impacting a growing number of people each year. The aims of the current experiment were to assess neuronal mechanisms involved in the initial plasticity after traumatic noise exposure that could contribute to the emergence of tinnitus and to test a potential pharmacological treatment to alter this early neural plasticity. Specifically, this study addressed rapid effects of acute noise trauma on amygdalo-hippocampal circuitry, characterizing biomarkers of both excitation and inhibition in these limbic regions, and compared them to expression of these same markers...
Source: Hearing Research - September 30, 2016 Category: Audiology Authors: Kapolowicz MR, Thompson LT Tags: Hear Res Source Type: research

The potential use of low-frequency tones to locate regions of outer hair cell loss.
In this study, we lowered the concentration of ouabain to 1 mM and determined the physiologic effects on outer hair cells using distortion-product otoacoustic emissions. As well as quantifying the effects of 1 mM ouabain on the auditory nerve and outer hair cells, we attempted to reduce the neural contribution to the CR by using near-infrasonic stimulus frequencies of 45 and 85 Hz, and hypothesized that these low-frequency stimuli would generate a cumulative amplitude function (CAF) that could reflect damage to hair cells in the apex more accurately than the 762 stimuli. One hour after application of 1 ...
Source: Hearing Research - September 23, 2016 Category: Audiology Authors: Kamerer A, Diaz FJ, Peppi M, Chertoff M Tags: Hear Res Source Type: research

Differential tinnitus-related neuroplastic alterations of cortical thickness and surface area.
Abstract Structural neuroimaging techniques have been used to identify cortical and subcortical regions constituting the neuroarchitecture of tinnitus. One recent investigation used voxel-based morphometry (VBM) to analyze a sample of tinnitus patients (TI, n=257) [1]. A negative relationship between individual distress and cortical volume (CV) in bilateral auditory regions was observed. However, CV has meanwhile been identified as a neuroanatomical measurement that confounds genetically distinct neuroanatomical traits, namely cortical thickness (CT) and cortical surface area (CSA). We performed a re-analysis of t...
Source: Hearing Research - September 22, 2016 Category: Audiology Authors: Meyer M, Neff P, Liem F, Kleinjung T, Weidt S, Langguth B, Schecklmann M Tags: Hear Res Source Type: research

Reorganization of neural systems mediating peripheral visual selective attention in the deaf: An optical imaging study.
We report data from severe to profoundly deaf adults and normal-hearing controls who performed the Useful Field of View task while cortical activity was recorded using the event-related optical signal. Behavioral performance, obtained in a separate session, showed that deaf subjects had lower thresholds (i.e., better performance) on the Useful Field of View task. The event-related optical data indicated greater activity for the deaf adults than for the normal-hearing controls during the task in the posterior portion of Brodmann area 22 in the right hemisphere. Furthermore, the behavioral thresholds correlated significantly...
Source: Hearing Research - September 22, 2016 Category: Audiology Authors: Seymour JL, Low KA, Maclin EL, Chiarelli AM, Mathewson KE, Fabiani M, Gratton G, Dye MW Tags: Hear Res Source Type: research

Circadian regulation of auditory function.
PMID: 27665709 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - September 21, 2016 Category: Audiology Authors: Basinou V, Park JS, Cederroth CR, Canlon B Tags: Hear Res Source Type: research

Study of tonotopic brain changes with functional MRI and FDG-PET in a patient with unilateral objective cochlear tinnitus.
The objective cochlear tinnitus was measured by Spontaneous Otoacoustic Emissions (SOAE) equipment (frequency 9689 Hz, intensity 57 dB SPL) and is clearly audible to anyone standing near the patient. Functional modifications in primary auditory areas and other brain regions were evaluated using 3T and 7T fMRI and FDG-PET. In the fMRI evaluations, a saturation of the auditory cortex at the tinnitus frequency was observed, but the global cortical tonotopic organization remained intact when compared to the results of fMRI of healthy subjects. The FDG-PET showed no evidence of an increase or decrease of activity in the auditor...
Source: Hearing Research - September 19, 2016 Category: Audiology Authors: Guinchard AC, Ghazaleh N, Saenz M, Fornari E, Prior JO, Maeder P, Adib S, Maire R Tags: Hear Res Source Type: research

Hearing sensitivity differs between zebrafish lines used in auditory research.
Abstract Zebrafish are increasingly used in auditory studies, in part due to the development of several transgenic lines that express hair cell-specific fluorescent proteins. However, it is largely unknown how transgene expression influences auditory phenotype. We previously observed reduced auditory sensitivity in adult Brn3c:mGFP transgenic zebrafish, which express membrane-bound green fluorescent protein (GFP) in sensory hair cells. Here, we examine the auditory sensitivity of zebrafish from multiple transgenic and background strains. We recorded auditory evoked potentials in adult animals and observed signific...
Source: Hearing Research - September 16, 2016 Category: Audiology Authors: Monroe JD, Manning DP, Uribe PM, Bhandiwad A, Sisneros JA, Smith ME, Coffin AB Tags: Hear Res Source Type: research

Higher-order auditory areas in congenital deafness: Top-down interactions and corticocortical decoupling.
Abstract The theory of predictive coding assumes that higher-order representations influence lower-order representations by generating predictions about sensory input. In congenital deafness, one identified dysfunction is a reduced activation of deep layers in the auditory cortex. Since these layers play a central role for processing top-down influences, congenital deafness might interfere with the integration of top-down and bottom-up information flow. Studies in humans suggest more deficits in higher-order than in primary cortical areas in congenital deafness. That opens up the question how well neurons in highe...
Source: Hearing Research - September 12, 2016 Category: Audiology Authors: Kral A, Yusuf PA, Land R Tags: Hear Res Source Type: research

Time course and frequency specificity of sub-cortical plasticity in adults following acute unilateral deprivation.
Abstract Auditory deprivation and stimulation can change the threshold of the acoustic reflex, but the mechanisms underlying these changes remain largely unknown. In order to elucidate the mechanism, we sought to characterize the time-course as well as the frequency specificity of changes in acoustic reflex thresholds (ARTs). In addition, we compared ipsilateral and contralateral measurements because the pattern of findings may shed light on the anatomical location of the change in neural gain. Twenty-four normal-hearing adults wore an earplug continuously in one ear for six days. We measured ipsilateral and contr...
Source: Hearing Research - September 9, 2016 Category: Audiology Authors: Brotherton H, Plack CJ, Schaette R, Munro KJ Tags: Hear Res Source Type: research

Dopaminergic projections of the subparafascicular thalamic nucleus to the auditory brainstem.
Abstract Neuromodulators can alter the response properties of sensory neurons, including those in the auditory system. Dopamine, which plays a major role in reward and movement, has been shown to alter neural responses in the auditory brainstem and midbrain. Recently we identified the subparafascicular thalamic nucleus (SPF), part of the A11 dopaminergic cell group, as the source of dopamine to the inferior colliculus (IC). The superior olivary complex (SOC) is also a likely target of dopaminergic projections from the SPF because it receives projections from the SPF and contains fibers and terminals immunoreactive...
Source: Hearing Research - September 9, 2016 Category: Audiology Authors: Nevue AA, Felix RA, Portfors CV Tags: Hear Res Source Type: research

Cross-modal Plasticity in Developmental and Age-Related Hearing Loss: Clinical Implications.
We describe developmental cross-modal re-organization in the context of congenital or pre-lingual deafness in childhood and in the context of adult-onset, age-related hearing loss, with a focus on how cross-modal plasticity relates to clinical outcomes. We provide both single-subject and group-level evidence of cross-modal re-organization by the visual and somatosensory systems in bilateral, congenital deafness, single-sided deafness, adults with early-stage, mild-moderate hearing loss, and individual adult and pediatric patients exhibit excellent and average speech perception with hearing aids and cochlear implants. We di...
Source: Hearing Research - September 5, 2016 Category: Audiology Authors: Glick H, Sharma A Tags: Hear Res Source Type: research

A tri-coil bellows-type round window transducer with improved frequency characteristics for middle-ear implants.
In this study, a new tri-coil bellows-type transducer (TCBT), which has excellent low frequency output and is easy to implant, is proposed. To design the frequency characteristics of the TCBT, mechanical and electrical simulations were performed, and then a comparative analysis was conducted between a floating mass type transducer (like the FMT) and a fixed type transducer (like the TCBT). The features of the proposed TCBT are as follows. First, the TCBT's housing is fixed to the RW niche so that it does not vibrate. Second, the internal end of a tiny bellows is connected to a vibrating three-pole permanent magnet located ...
Source: Hearing Research - September 1, 2016 Category: Audiology Authors: Shin DH, Seong KW, Puria S, Lee KY, Cho JH Tags: Hear Res Source Type: research

A fast, stochastic, and adaptive model of auditory nerve responses to cochlear implant stimulation.
In this study, a computationally efficient model that accurately predicts auditory nerve responses to CI pulse train input was developed. A three-dimensional volume conduction and active nerve model developed at Leiden University Medical Center was extended with stochasticity, adaptation, and accommodation. This complete model includes spatial and temporal characteristics of both the cochlea and the auditory nerve. The model was validated by comparison with experimentally measured single fiber action potential responses to pulse trains published in the literature. The effects of pulse rate and pulse amplitude on spiking pa...
Source: Hearing Research - September 1, 2016 Category: Audiology Authors: van Gendt MJ, Briaire JJ, Kalkman RK, Frijns JH Tags: Hear Res Source Type: research

Speech perception adjusts to stable spectrotemporal properties of the listening environment.
Abstract When perceiving speech, listeners compensate for reverberation and stable spectral peaks in the speech signal. Despite natural listening conditions usually adding both reverberation and spectral coloration, these processes have only been studied separately. Reverberation smears spectral peaks across time, which is predicted to increase listeners' compensation for these peaks. This prediction was tested using sentences presented with or without a simulated reverberant sound field. All sentences had a stable spectral peak (added by amplifying frequencies matching the second formant frequency [F2] in the tar...
Source: Hearing Research - September 1, 2016 Category: Audiology Authors: Stilp CE, Anderson PW, Assgari AA, Ellis GM, Zahorik P Tags: Hear Res Source Type: research

The effect of distraction on change detection in crowded acoustic scenes.
Abstract In this series of behavioural experiments we investigated the effect of distraction on the maintenance of acoustic scene information in short-term memory. Stimuli are artificial acoustic 'scenes' composed of several (up to twelve) concurrent tone-pip streams ('sources'). A gap (1000 ms) is inserted partway through the 'scene'; Changes in the form of an appearance of a new source or disappearance of an existing source, occur after the gap in 50% of the trials. Listeners were instructed to monitor the unfolding 'soundscapes' for these events. Distraction was measured by presenting distractor stimuli du...
Source: Hearing Research - September 1, 2016 Category: Audiology Authors: Petsas T, Harrison J, Kashino M, Furukawa S, Chait M Tags: Hear Res Source Type: research

Modelling the effect of round window stiffness on residual hearing after cochlear implantation.
Abstract Preservation of residual hearing after cochlear implantation is now considered an important goal of surgery. However, studies indicate an average post-operative hearing loss of around 20 dB at low frequencies. One factor which may contribute to post-operative hearing loss, but which has received little attention in the literature to date, is the increased stiffness of the round window, due to the physical presence of the cochlear implant, and to its subsequent thickening or to bone growth around it. A finite element model was used to estimate that there is approximately a 100-fold increase in the round wi...
Source: Hearing Research - August 28, 2016 Category: Audiology Authors: Elliott SJ, Ni G, Verschuur CA Tags: Hear Res Source Type: research

The effects of aging and sex on detection of ultrasonic vocalizations by adult CBA/CaJ mice (Mus musculus).
In conclusion, the results highlight the importance of studying complex signals across the lifespan. PMID: 27579993 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - August 26, 2016 Category: Audiology Authors: Kobrina A, Dent ML Tags: Hear Res Source Type: research

The contribution of inferior colliculus activity to the auditory brainstem response (ABR) in mice.
In conclusion, the slow ABR wave P0 in the scalp ABR may represent a complementary non-invasive marker for IC activity in the mouse. Further, the latency of synchronized click-evoked activity in the IC supports the view that IC contributes to ABR wave V, and possibly also to ABR wave IV. PMID: 27562195 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - August 21, 2016 Category: Audiology Authors: Land R, Burghard A, Kral A Tags: Hear Res Source Type: research

Auditory Thalamic Circuits and GABAA Receptor Function: Putative Mechanisms in Tinnitus Pathology.
Abstract Tinnitus is defined as a phantom sound (ringing in the ears), and can significantly reduce the quality of life for those who suffer its effects. Ten to fifteen percent of the general adult population report symptoms of tinnitus with 1-2% reporting that tinnitus negatively impacts their quality of life. Noise exposure is the most common cause of tinnitus and the military environment presents many challenging high-noise situations. Military noise levels can be so intense that standard hearing protection is not adequate. Recent studies suggest a role for inhibitory neurotransmitter dysfunction in response to...
Source: Hearing Research - August 19, 2016 Category: Audiology Authors: Caspary DM, Llano DA Tags: Hear Res Source Type: research

Endothelin-1 Mediated Induction of Extracellular Matrix Genes in Strial Marginal Cells Underlies Strial Pathology in Alport Mice.
Abstract Alport syndrome, a type IV collagen disorder, manifests as glomerular disease associated with hearing loss with thickening of the glomerular and strial capillary basement membranes (SCBMs). We have identified a role for endothelin-1 (ET-1) activation of endothelin A receptors (ETARs) in glomerular pathogenesis. Here we explore whether ET-1 plays a role in strial pathology. Wild type (WT) and Alport mice were treated with the ETAR antagonist, sitaxentan. The stria vascularis was analyzed for SCBM thickness and for extracellular matrix (ECM) proteins. Additional WT and Alport mice were exposed to noise or h...
Source: Hearing Research - August 19, 2016 Category: Audiology Authors: Meehan DT, Delimont D, Dufek B, Zallocchi M, Phillips G, Gratton MA, Cosgrove D Tags: Hear Res Source Type: research

Low-Frequency Bias Tone Suppression of Auditory-Nerve Responses to Low-Level Clicks and Tones.
Abstract We used low-frequency "bias" tones (BT's) to explore whether click and tone responses are affected in the same way by cochlear active processes. In nonlinear systems the responses to clicks are not always simply related to the responses to tones. Cochlear amplifier gain depends on the incremental slope of the outer-hair-cell (OHC) stereocilia mechano-electric transductance (MET) function. BTs transiently change the operating-point of OHC MET channels and can suppress cochlear-amplifier gain by pushing OHC METs into low-slope saturation regions. BT effects on single auditory-nerve (AN) fibers hav...
Source: Hearing Research - August 17, 2016 Category: Audiology Authors: Nam H, Guinan JJ Tags: Hear Res Source Type: research

Differences in synaptic and intrinsic properties result in topographic heterogeneity of temporal processing of neurons within the inferior colliculus.
Abstract The identification and characterization of organization principals is essential for the understanding of neural function of brain areas. The inferior colliculus (IC) represents a midbrain nexus involved in numerous aspects of auditory processing. Likewise, neurons throughout the IC are tuned to a diverse range of specific stimulus features. Yet beyond a topographic arrangement of the cochlea-inherited frequency tuning, the functional organization of the IC is not well understood. Particularly, a common principle that links the diverse tuning characteristics is unknown. Here we used in vitro patch cla...
Source: Hearing Research - August 16, 2016 Category: Audiology Authors: Yassin L, Pecka M, Kajopoulos J, Gleiss H, Li L, Leibold C, Felmy F Tags: Hear Res Source Type: research

Across-site patterns of electrically evoked compound action potential amplitude-growth functions in multichannel cochlear implant recipients and the effects of the interphase gap.
Abstract Electrically evoked compound action potential (ECAP) measures of peak amplitude, and amplitude-growth function (AGF) slope have been shown to reflect characteristics of cochlear health (primarily spiral ganglion density) in anesthetized cochlear-implanted guinea pigs. Likewise, the effect of increasing the interphase gap (IPG) in each of these measures also reflects SGN density in the implanted guinea pig. Based on these findings, we hypothesize that suprathreshold ECAP measures, and also how they change as the IPG is increased, have the potential to be clinically applicable in human subjects. However, fu...
Source: Hearing Research - August 9, 2016 Category: Audiology Authors: Schvartz-Leyzac KC, Pfingst BE Tags: Hear Res Source Type: research

Effects of sustained release dexamethasone hydrogels in hearing preservation cochlear implantation.
r C Abstract It has been shown that glucocorticoids reduce the hearing threshold shifts associated with cochlear implantation. Previous studies evaluated the administration of glucocorticoids immediately before surgery or the repeated pre- or perioperative systemic application of glucocorticoids. The aim of this study was to evaluate the effects of a sustained release dexamethasone hydrogel in hearing preservation cochlear implantation. To address this issue, a guinea pig model of cochlear implantation was used. 30 normal hearing pigmented guinea pigs were randomized into a group receiving a single dose of a dexam...
Source: Hearing Research - August 8, 2016 Category: Audiology Authors: Honeder C, Zhu C, Schöpper H, Gausterer JC, Walter M, Landegger LD, Saidov N, Riss D, Plasenzotti R, Gabor F, Arnoldner C Tags: Hear Res Source Type: research

Controlled exploration of the effects of conductive hearing loss on wideband acoustic immittance in human cadaveric preparations.
We report measurements before and after simulation of stapes fixation (n = 8), malleus fixation (n = 10), ossicular disarticulation (n = 10), and superior canal dehiscence (n = 8). Our results are consistent with the small set of previously published reflectance measurements made in temporal bones and patients. In this present study, these temporal bone experiments with different middle- and inner-ear pathologies were compared to the initial normal state by analyzing both WAI and ossicular motion, demonstrating that WAI can be a valuable tool in the diagnosis of conductive hearing lo...
Source: Hearing Research - August 2, 2016 Category: Audiology Authors: Merchant GR, Merchant SN, Rosowski JJ, Nakajima HH Tags: Hear Res Source Type: research

Vestibular-dependent inter-stimulus interval effects on sound evoked potentials of central origin.
Abstract Todd et al. (2014ab) have recently demonstrated the presence of vestibular-dependent contributions to auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs), including a particular deflection labeled as an N42/P52 prior to the long-latency AEPs N1 and P2. In this paper we report the results of an experiment to determine the effect of inter-stimulus interval (ISI) and regularity on potentials recorded above and below VEMP threshold. Five healthy, right-handed subjects were recruited and evoked potentials were recor...
Source: Hearing Research - August 2, 2016 Category: Audiology Authors: Todd NP, Govender S, Colebatch JG Tags: Hear Res Source Type: research

Frequency discrimination in the common marmoset (Callithrix jacchus).
Abstract The common marmoset (Callithrix jacchus) is a highly vocal New World primate species that has emerged in recent years as a promising model system for studies of auditory and vocal processing. Our recent studies have examined perceptual mechanisms related to the pitch of harmonic complex tones in this species. However, no previous psychoacoustic work has measured marmosets' frequency discrimination abilities for pure tones across a broad frequency range. Here we systematically examined frequency difference limens (FDLs), which measure the minimum discriminable frequency difference between two pure tones, i...
Source: Hearing Research - August 2, 2016 Category: Audiology Authors: Osmanski MS, Song X, Guo Y, Wang X Tags: Hear Res Source Type: research

Drug discovery for hearing loss: Phenotypic screening of chemical compounds on primary cultures of the spiral ganglion.
Abstract In the United States there are, at present, no drugs that are specifically FDA approved to treat hearing loss. Although several clinical trials are ongoing, including one testing D-methionine that is supported by the US Army, none of these trials directly address the effect of noise exposure on cochlear spiral ganglion neurons. We recently published the first report of a systematic chemical compound screen using primary, mammalian spiral ganglion cultures in which we were able to detect a compound and others in its class that increased neurite elongation, a critical step in restoring cochlear synapses aft...
Source: Hearing Research - August 1, 2016 Category: Audiology Authors: Whitlon DS Tags: Hear Res Source Type: research

Does the degree of linguistic experience (native versus nonnative) modulate the degree to which listeners can benefit from a delay between the onset of the maskers and the onset of the target speech?
Abstract Background noise has a greater adverse effect on word recognition when people are listening in their second language (L2) as opposed to their first language (L1). The present study investigates the extent to which linguistic experience affects the ability of L2 listeners to benefit from a delay between the onset of a masker and the onset of a word. In a previous study (Ben-David, Tse & Schneider, 2012), word recognition thresholds for young L1s were found to improve with the increase in the delay between the onset of a masker (either a stationary noise or a babble of voices) and the onset of a word. T...
Source: Hearing Research - August 1, 2016 Category: Audiology Authors: Ben-David BM, Avivi-Reich M, Schneider BA Tags: Hear Res Source Type: research

Evidence of activity-dependent plasticity in the dorsal cochlear nucleus, in  vivo, induced by brief sound exposure.
We examined the levels of multi- and single-unit spontaneous activity before and immediately following brief exposure (2 min) to tones at levels of either 109 or 85 dB SPL. Exposure frequency was selected to either correspond to the units' best frequency (BF) or fall within the borders of its inhibitory side band. The results demonstrate that these exposure conditions caused significant alterations in spontaneous activity and responses to BF tones. The induced changes have a fast onset (minutes) and are persistent for durations of at least 20 min. The directions of the change were found to depend on the freq...
Source: Hearing Research - July 31, 2016 Category: Audiology Authors: Gao Y, Manzoor N, Kaltenbach JA Tags: Hear Res Source Type: research

Motion of tympanic membrane in guinea pig otitis media model measured by scanning laser Doppler vibrometry.
In this study, the guinea pig AOM and OME models were created by transbullar injection of Streptococcus pneumoniae type 3 and lipopolysaccharide, respectively. To explore the effects of OM on the entire TM vibration, the measurements of full-field TM motions were performed in the AOM, OME and untreated control ears by using scanning laser Doppler vibrometry (SLDV). The results showed that both AOM and OME generally reduced the displacement peak and produced the traveling-wave-like motions at relatively low frequencies. Compared with the normal ear, OME resulted in a significant change of the TM displacement mainly in the i...
Source: Hearing Research - July 31, 2016 Category: Audiology Authors: Wang X, Guan X, Pineda M, Gan RZ Tags: Hear Res Source Type: research

Plasticity in bilateral superior temporal cortex: effects of deafness and cochlear implantation on auditory and visual speech processing.
Abstract While many individuals can benefit substantially from cochlear implantation, the ability to perceive and understand auditory speech with a cochlear implant (CI) remains highly variable amongst adult recipients. Importantly, auditory performance with a CI cannot be reliably predicted based solely on routinely obtained information regarding clinical characteristics of the CI candidate. This review argues that central factors, notably cortical function and plasticity, should also be considered as important contributors to the observed individual variability in CI outcome. Superior temporal cortex (STC), incl...
Source: Hearing Research - July 25, 2016 Category: Audiology Authors: Anderson CA, Lazard DS, Hartley DE Tags: Hear Res Source Type: research

The effect of progressive hearing loss on the morphology of endbulbs of Held and bushy cells.
Abstract Studies of congenital and early-onset deafness have demonstrated that an absence of peripheral sound-evoked activity in the auditory nerve causes pathological changes in central auditory structures. The aim of this study was to establish whether progressive acquired hearing loss could lead to similar brain changes that would degrade the precision of signal transmission. We used complementary physiologic hearing tests and microscopic techniques to study the combined effect of both magnitude and duration of hearing loss on one of the first auditory synapses in the brain, the endbulb of Held (EB), along with...
Source: Hearing Research - July 25, 2016 Category: Audiology Authors: Connelly CJ, Ryugo DK, Muniak MA Tags: Hear Res Source Type: research

Cortical reorganization in postlingually deaf cochlear implant users: intra-modal and cross-modal considerations.
Abstract With the advances of cochlear implant (CI) technology, many deaf individuals can partially regain their hearing ability. However, there is a large variation in the level of recovery. Cortical changes induced by hearing deprivation and restoration with CIs have been thought to contribute to this variation. The current review aims to identify these cortical changes in postlingually deaf CI users and discusses their maladaptive or adaptive relationship to the CI outcome. Overall, intra-modal and cross-modal reorganization patterns have been identified in postlingually deaf CI users in visual and in auditory ...
Source: Hearing Research - July 25, 2016 Category: Audiology Authors: Stropahl M, Chen LC, Debener S Tags: Hear Res Source Type: research

Capturing contextual effects in spectro-temporal receptive fields.
PJ Abstract Spectro-temporal receptive fields (STRFs) are thought to provide descriptive images of the computations performed by neurons along the auditory pathway. However, their validity can be questioned because they rely on a set of assumptions that are probably not fulfilled by real neurons exhibiting contextual effects, that is, nonlinear interactions in the time or frequency dimension that cannot be described with a linear filter. We used a novel approach to investigate how a variety of contextual effects, due to facilitating nonlinear interactions and synaptic depression, affect different STRF models, and...
Source: Hearing Research - July 25, 2016 Category: Audiology Authors: Westö J, May PJ Tags: Hear Res Source Type: research

Atypical white-matter microstructure in congenitally deaf adults: a region of interest and tractography study using diffusion-tensor imaging.
Abstract Considerable research documents the cross-modal reorganization of auditory cortices as a consequence of congenital deafness, with remapped functions that include visual and somatosensory processing of both linguistic and nonlinguistic information. Structural changes accompany this cross-modal neuroplasticity, but precisely which specific structural changes accompany congenital and early deafness and whether there are group differences in hemispheric asymmetries remain to be established. Here, we used diffusion tensor imaging (DTI) to examine microstructural white matter changes accompanying cross-modal re...
Source: Hearing Research - July 25, 2016 Category: Audiology Authors: Karns CM, Stevens C, Dow MW, Schorr E, Neville HJ Tags: Hear Res Source Type: research

Acoustic input impedance of the avian inner ear measured in ostrich (Struthio camelus).
In this study, the aim was to quantify the acoustic impedance of the avian inner ear in the ostrich, which allows us to determine the effect on columellar vibrations and middle ear power flow in future studies. To determine the inner ear impedance, vibrations of the columella were measured for both the quasi-static and acoustic stimulus frequencies. In the frequency range of 0.3-4 kHz, we used electromagnetic stimulation of the ossicle and a laser Doppler vibrometer to measure the vibration response. At low frequencies, harmonic displacements were imposed on the columella using piezo stimulation and the resulting force res...
Source: Hearing Research - July 25, 2016 Category: Audiology Authors: Muyshondt PG, Aerts P, Dirckx JJ Tags: Hear Res Source Type: research

Seasonal variations in auditory processing in the inferior colliculus of Eptesicus fuscus.
Abstract Eptesicus fuscus is typical of temperate zone bats in that both sexes undergo marked seasonal changes in behavior, endocrine status, and reproductive status. Acoustic communication plays a key role in many seasonal behaviors. For example, males emit specialized vocalizations during mating in the fall, and females use different specialized vocalizations to communicate with infants in late spring. Bats of both sexes use echolocation for foraging during times of activity, but engage in little sound-directed behavior during torpor and hibernation in winter. Auditory processing might be expected to reflect the...
Source: Hearing Research - July 25, 2016 Category: Audiology Authors: Miller KE, Barr K, Krawczyk M, Covey E Tags: Hear Res Source Type: research

Neurofilament heavy chain expression and neuroplasticity in rat auditory cortex after unilateral and bilateral deafness.
Abstract Deafness induces many plastic changes in the auditory neural system. For instance, dendritic changes cause synaptic changes in neural cells. SMI-32, a monoclonal antibody reveals auditory areas and recognizes non-phosphorylated epitopes on medium- and high-molecular-weight subunits of neurofilament proteins in cortical pyramidal neuron dendrites. We investigated SMI-32-immunoreactive (-ir) protein levels in the auditory cortices of rats with induced unilateral and bilateral deafness. Adult male Sprague-Dawley rats were divided into unilateral deafness (UD), bilateral deafness (BD), and control groups. Dea...
Source: Hearing Research - July 21, 2016 Category: Audiology Authors: Park MH, Jang JH, Song JJ, Lee HS, Oh SH Tags: Hear Res Source Type: research

Speech-evoked activation in adult temporal cortex measured using functional near-infrared spectroscopy (fNIRS): Are the measurements reliable?
Abstract Functional near-infrared spectroscopy (fNIRS) is a silent, non-invasive neuroimaging technique that is potentially well suited to auditory research. However, the reliability of auditory-evoked activation measured using fNIRS is largely unknown. The present study investigated the test-retest reliability of speech-evoked fNIRS responses in normally-hearing adults. Seventeen participants underwent fNIRS imaging in two sessions separated by three months. In a block design, participants were presented with auditory speech, visual speech (silent speechreading), and audiovisual speech conditions. Optode arrays w...
Source: Hearing Research - July 20, 2016 Category: Audiology Authors: Wiggins IM, Anderson CA, Kitterick PT, Hartley DE Tags: Hear Res Source Type: research

Volumes of Cochlear Nucleus Regions in Rodents.
Abstract The cochlear nucleus receives all the coded information about sound from the cochlea and is the source of auditory information for the rest of the central auditory system. As such, it is a critical auditory nucleus. The sizes of the cochlear nucleus as a whole and its three major subdivisions - anteroventral cochlear nucleus (AVCN), posteroventral cochlear nucleus (PVCN), and dorsal cochlear nucleus (DCN) - have been measured in a large number of mammals, but measurements of its subregions at a more detailed level for a variety of species have not previously been made. Size measurements are reported here ...
Source: Hearing Research - July 15, 2016 Category: Audiology Authors: Godfrey DA, Lee AC, Hamilton WD, Benjamin LC, Vishwanath S, Simo H, Godfrey LM, Mustapha AI, Heffner RS Tags: Hear Res Source Type: research

Response to Letter: Whole scalp EEG power change is not a prerequisite for further EEG processing.
PMID: 27426297 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - July 13, 2016 Category: Audiology Authors: Hall DA, Pierzycki RH, Hoare DJ, McNamara AJ Tags: Hear Res Source Type: research

Whole scalp EEG power change is not a prerequisite for further EEG processing.
PMID: 27424300 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - July 13, 2016 Category: Audiology Authors: De Ridder D, Congedo M, Song JJ, Vanneste S Tags: Hear Res Source Type: research

Reprint of: Immune defense is the primary function associated with the differentially expressed genes in the cochlea following acoustic trauma.
Abstract Our previous RNA-sequencing analysis of the rat cochlear genes identified multiple biological processes and molecular pathways in the cochlear response to acoustic overstimulation. However, the biological processes and molecular pathways that are common to other species have not been documented. The identification of these common stress processes is pivotal for a better understanding of the essential response of the cochlea to acoustic injury. Here, we compared the RNA-sequencing data collected from mice and rats that sustained a similar, but not identical, acoustic injury. The transcriptome analysis of c...
Source: Hearing Research - July 8, 2016 Category: Audiology Authors: Yang S, Cai Q, Vethanayagam RR, Wang J, Yang W, Hu BH Tags: Hear Res Source Type: research

Crossmodal plasticity in auditory, visual and multisensory cortical areas following noise-induced hearing loss in adulthood.
Abstract Complete or partial hearing loss results in an increased responsiveness of neurons in the core auditory cortex of numerous species to visual and/or tactile stimuli (i.e., crossmodal plasticity). At present, however, it remains uncertain how adult-onset partial hearing loss affects higher-order cortical areas that normally integrate audiovisual information. To that end, extracellular electrophysiological recordings were performed under anesthesia in noise-exposed rats two weeks post-exposure (0.8-20 kHz at 120 dB SPL for 2 h) and age-matched controls to characterize the nature and extent of crossmodal plas...
Source: Hearing Research - July 3, 2016 Category: Audiology Authors: Schormans AL, Typlt M, Allman BL Tags: Hear Res Source Type: research

Place dependent stimulation rates improve pitch perception in cochlear implantees with single-sided deafness.
aumann U Abstract In normal hearing, the pitch of an acoustic tone can theoretically be encoded by either the place of stimulation in the cochlea or the corresponding rate of vibration. Thus spectral attributes and temporal fine structure of an acoustic signal are naturally correlated. Cochlear implants (CIs), neural prosthetic devices that restore hearing in the profoundly hearing impaired, currently disregard this mechanism; electrical stimulation is provided at fixed electrode positions with default place independent stimulation rate assignments. This does not account for individual cochlear encoding depending ...
Source: Hearing Research - June 30, 2016 Category: Audiology Authors: Rader T, Döge J, Adel Y, Weißgerber T, Baumann U Tags: Hear Res Source Type: research

Endolymph Movement Visualized with Light Sheet Fluorescence Microscopy in an Acute Hydrops Model.
Abstract There are a variety of techniques available to investigate endolymph dynamics, primarily seeking to understand the cause of endolymphatic hydrops. Here we have taken the novel approach of injecting, via a glass micropipette, fluorescein isothiocyanate-dextran (FITC-dex) + artificial endolymph into scala media of anaesthetized guinea pigs, with subsequent imaging of the inner ear using Light Sheet Fluorescence Microscopy (LSFM) as a means to obtain highly resolved 3D visualization of fluid movements. Our results demonstrate endolymph movement into the utricle, semicircular canals and endolymphatic duct and...
Source: Hearing Research - June 30, 2016 Category: Audiology Authors: Brown DJ, Pastras C, Curthoys IS, Southwell CS, Van Roon L Tags: Hear Res Source Type: research

Subcortical correlates of auditory perceptual organization in humans.
Abstract To make sense of complex auditory scenes, the auditory system sequentially organizes auditory components into perceptual objects or streams. In the conventional view of this process, the cortex plays a major role in perceptual organization, and subcortical mechanisms merely provide the cortex with acoustical features. Here, we show that the neural activities of the brainstem are linked to perceptual organization, which alternates spontaneously for human listeners without any stimulus change. The stimulus used in the experiment was an unchanging sequence of repeated triplet tones, which can be interpreted ...
Source: Hearing Research - June 28, 2016 Category: Audiology Authors: Yamagishi S, Otsuka S, Furukawa S, Kashino M Tags: Hear Res Source Type: research

Correlation between word recognition score and intracochlear new bone and fibrous tissue after cochlear implantation in the human.
Abstract Cochlear implantation is an effective, established procedure for patients with profound deafness. Although implant electrodes have been considered as biocompatible prostheses, surgical insertion of the electrode induces various changes within the cochlea. Immediate changes include insertional trauma to the cochlea. Delayed changes include a tissue response consisting of inflammation, fibrosis and neo-osteogenesis induced by trauma and an immunologic reaction to a foreign body. The goal of this study was to evaluate the effect of these delayed changes on the word recognition scores achieved post-operativel...
Source: Hearing Research - June 28, 2016 Category: Audiology Authors: Kamakura T, Nadol JB Tags: Hear Res Source Type: research

Prepulse inhibition of the acoustic startle reflex vs. auditory brainstem response for hearing assessment.
Abstract The high prevalence of noise-induced and age-related hearing loss in the general population has warranted the use of animal models to study the etiology of these pathologies. Quick and accurate auditory threshold determination is a prerequisite for experimental manipulations targeting hearing loss in animal models. The standard auditory brainstem response (ABR) measurement is fairly quick and translational across species, but is limited by the need for anesthesia and a lack of perceptual assessment. The goal of this study was to develop a new method of hearing assessment utilizing prepulse inhibition (PPI...
Source: Hearing Research - June 23, 2016 Category: Audiology Authors: Longenecker RJ, Alghamdi F, Rosen MJ, Galazyuk AV Tags: Hear Res Source Type: research