Hearing ResearchPub Date : 2026-10-01Epub Date: 2026-08-08DOI: 10.1016/j.heares.2026.109772
Emily B J Coffey, Philippe Fournier
{"title":"Special issue on misophonia and hyperacusis.","authors":"Emily B J Coffey, Philippe Fournier","doi":"10.1016/j.heares.2026.109772","DOIUrl":"10.1016/j.heares.2026.109772","url":null,"abstract":"","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":" ","pages":"109772"},"PeriodicalIF":3.0,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148792210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2026-08-30DOI: 10.1016/j.heares.2026.109791
Thiago Mathias de Oliveira, Amauri Amorin Assef, Denis de Jesus Batista, Joaquim Miguel Maia, Alexandre Francisco de Morais, Adriana Bender Moreira de Lacerda, Tiago da Silva Santos, Guilherme Augusto Queiroz Schunemann Manfrin De Oliveira
{"title":"Mathematical and computational modelling of cochlear responses to environmental noise exposure: A preliminary multiscale computational study.","authors":"Thiago Mathias de Oliveira, Amauri Amorin Assef, Denis de Jesus Batista, Joaquim Miguel Maia, Alexandre Francisco de Morais, Adriana Bender Moreira de Lacerda, Tiago da Silva Santos, Guilherme Augusto Queiroz Schunemann Manfrin De Oliveira","doi":"10.1016/j.heares.2026.109791","DOIUrl":"https://doi.org/10.1016/j.heares.2026.109791","url":null,"abstract":"<p><strong>Introduction: </strong>Environmental noise is recognised by the World Health Organization and the European Environment Agency as a major environmental risk factor. However, the biophysical mechanisms linking acoustic exposure to cochlear mechanical and neural responses remain incompletely characterised.</p><p><strong>Objective: </strong>This preliminary study organises established cochlear modelling approaches within a multiscale computational framework to examine how environmental sound levels are translated into passive mechanical responses and simulated neural activity.</p><p><strong>Methods: </strong>Passive in silico simulations were performed using three complementary computational modules: (i) a one-dimensional transmission-line model of longitudinal cochlear mechanics; (ii) a three-dimensional finite-difference time-domain model incorporating cochlear-fluid propagation and fluid-basilar-membrane coupling; and (iii) a perceptual post-processing pipeline based on equivalent rectangular bandwidth filtering, inner hair cell transduction, and stochastic auditory-nerve activity. Acoustic inputs included synthetic and environmental signals calibrated between 30 and 85 dB SPL. Both mechanical models were implemented under passive linear assumptions and did not include outer-hair-cell-mediated amplification, compressive nonlinearity, or level-dependent active tuning.</p><p><strong>Results: </strong>Higher acoustic input levels produced greater basilar membrane displacement in the 1D and 3D mechanical models, increased pressure magnitude in the three-dimensional fluid domain, and greater simulated neural activity and burstiness in the perceptual module. In the passive 1D model, increasing the input from 30 to 85 dB SPL produced an approximately 55 dB increase in basilar membrane displacement level while the normalised frequency-position ridge geometry remained essentially unchanged, consistent with proportional linear scaling. The derived characteristic-frequency and Q10 distributions reproduced the expected longitudinal tonotopic gradient within the frequency range reliably resolved by the simulations, although their extension into the most apical region was limited by the 200 Hz lower-frequency boundary and the peak-identification criteria. The Environmental Auditory Risk Index was used as an exploratory, model-derived composite indicator for integrating the mechanical and simulated neural outputs evaluated in the study.</p><p><strong>Conclusion: </strong>The proposed framework provides a controlled computational representation of how environmental acoustic inputs are translated into passive cochlear mechanics and simulated neural activity across complementary modelling domains. The results should not be interpreted as evidence of active cochlear amplification, physiological injury, or clinically validated auditory risk. Incorporation of nonlinear outer hair cell mechanics, extension of the low-frequency simulation range, sensitivity a","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"481 ","pages":"109791"},"PeriodicalIF":3.0,"publicationDate":"2026-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148880228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2026-08-28DOI: 10.1016/j.heares.2026.109790
David López-Ramos, Almudena Eustaquio-Martín, Miriam I Marrufo-Pérez, Luis E López-Bascuas, Enrique A Lopez-Poveda
{"title":"The effect of sound level and signal-to-noise ratio on adaptation to noise in spectral and temporal modulation detection.","authors":"David López-Ramos, Almudena Eustaquio-Martín, Miriam I Marrufo-Pérez, Luis E López-Bascuas, Enrique A Lopez-Poveda","doi":"10.1016/j.heares.2026.109790","DOIUrl":"https://doi.org/10.1016/j.heares.2026.109790","url":null,"abstract":"<p><p>Adaptation to noise is the improvement in auditory function as the signal of interest is delayed in the noise. Previous research has shown that adaptation to noise occurs in the detection of temporal and spectral modulations when these modulations occur separately but not when they occur simultaneously. The aim of the present study was to investigate if adaptation to noise in spectral and temporal modulation detection depends on the signal level or on the signal-to-noise ratio (SNR). The signal was a 200-ms spectrally (2 cycles/oct) or temporally (10 Hz) modulated ripple noise embedded in white noise with noise-signal onset delays of 50 ms (early condition) and 800 ms (late condition). Adaptation was calculated as the improvement in the modulation detection threshold in the late condition with respect to the early condition. To explore if adaptation depends on the sound level (Experiment 1), adaptation was measured for ripple noise levels of 45, 60 and 75 dB SPL and a fixed SNR of 0 dB. Statistically significant adaptation occurred in spectral modulation detection at all three levels. Adaptation in temporal modulation detection was statistically significant at 60 and 75 dB SPL, but not at 45 dB SPL. To explore if adaptation to noise depends on the SNR (Experiment 2), adaptation was measured for five SNRs (-10, -5, 0, 5 and 10 dB) while fixing the level of the white noise at 60 dB SPL. Adaptation in spectral modulation detection was statistically significant for all SNRs except +5 dB. Adaptation in temporal modulation detection was statistically significant only at -10 and 0 dB SNR. Findings are discussed with regard to potential mechanisms involved in adaptation to noise.</p>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"481 ","pages":"109790"},"PeriodicalIF":3.0,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148887091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2026-08-28DOI: 10.1016/j.heares.2026.109781
Renata Sisto, Arturo Moleti
{"title":"Close-to-critical Hopf oscillators boost cochlear gain in realistic models with fluid focusing.","authors":"Renata Sisto, Arturo Moleti","doi":"10.1016/j.heares.2026.109781","DOIUrl":"https://doi.org/10.1016/j.heares.2026.109781","url":null,"abstract":"<p><p>Critical Hopf oscillators have been proposed for modeling the cochlear micromechanics, and the generation of spontaneous otoacoustic emissions. In such top-down models, the cochlear micromechanical elements are abstractly represented through equations written in normal form. There is a gap to be filled between this abstract formulation and the complexity of the motion of the Organ of Corti as revealed by recent optical coherent tomography measurements. The aim of the present work is bridging this gap using a bottom-up approach: starting from realistic equations schematizing the actual physical elements of cochlear micromechanics, we show explicitly how these equations admit a normal form representation. To do that, the Organ of Corti is schematized as a system of two oscillators coupled by an internal active low-passed nonlinear force, and to an incompressible 2D fluid. We generalize the classical two-equation normal form to a three-equation system, demonstrating that the normal form approach may be used to compute the relative motion of the main elements of the Organ of Corti, while the center of mass motion depends on the fluid forces only. This way, the parameters of the critical oscillator are no longer abstract mathematical quantities, but acquire a direct physical interpretation in terms of the dynamics of the underlying physical elements. In particular, the approach to the critical behavior, and the consequent dramatic variation of the cochlear response gain and bandwidth, are quantified in terms of a few dimensionless parameters of obvious physiological meaning.</p>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"481 ","pages":"109781"},"PeriodicalIF":3.0,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148864606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2026-08-26DOI: 10.1016/j.heares.2026.109788
Melissa M McGovern, Luyi Zhou, Michelle R Randle, Andrew K Groves, Brandon C Cox
{"title":"SOX10 restricts the formation of ectopic sensory patches in the postnatal mouse cochlea.","authors":"Melissa M McGovern, Luyi Zhou, Michelle R Randle, Andrew K Groves, Brandon C Cox","doi":"10.1016/j.heares.2026.109788","DOIUrl":"https://doi.org/10.1016/j.heares.2026.109788","url":null,"abstract":"<p><p>During the development of the mammalian cochlea, Notch signaling induces prosensory cell formation and later directs the differentiation of prosensory progenitor cells into hair cells and supporting cells. Previous studies have demonstrated that ectopic activation of Notch signaling in the early embryonic cochlea results in the formation of ectopic sensory patches in non-sensory regions; however, the ability to respond to Notch signaling declines with age and is lost after embryonic day (E) 13.5. Here, we observed that Notch activation at birth induced ectopic sensory patches in the mouse cochlea. These ectopic patches produced hair cell-like cells that express some proteins found in mature hair cells. Ectopic sensory patches result from hyperplasia of non-sensory cells throughout the cochlear duct that reentered the cell cycle and produced foci of prosensory competent cells. Within the organ of Corti, cells remained quiescent, however, cellular patterning was altered leading to differentiation of outer sulcus cells into supporting cell-like cells and altering the identity of pillar cells. We further investigated different levels of activated Notch signaling using a doxycycline-inducible system and found that the competence of the neonatal cochlea to induce prosensory markers, such as Sox2, correlates with the level of Notch activation, whereby higher levels of Notch signaling induced ectopic Sox2 expression. Because this conflicted with previous reports, we investigated the mechanism underlying prosensory reactivation in our experiments and found that the loss of one copy of Sox10 resulting from our use of Sox10rt<sup>TA/+</sup>knock-in mice facilitated prosensory competence, and that higher levels of Notch activation increased the penetrance of the phenotype. Our results demonstrate that the interaction between Notch signaling and SOX10 is important for the regulation of cellular identity in the developing inner ear.</p>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"481 ","pages":"109788"},"PeriodicalIF":3.0,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148873844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hidden auditory dysfunction in tinnitus with normal audiograms: selective and chronicity-dependent ABR changes in middle-aged adults.","authors":"Qian He, Sheng-Yu Tao, Bingjie Li, Shiyu Kang, Xiaoliang Sheng, Ji-Sheng Liu, Duo-Duo Tao","doi":"10.1016/j.heares.2026.109786","DOIUrl":"https://doi.org/10.1016/j.heares.2026.109786","url":null,"abstract":"<p><p>Tinnitus can occur in adults with normal audiograms, suggesting subtle auditory dysfunction beyond conventional threshold measures. This study investigated whether middle-aged adults with tinnitus and clinically normal hearing show evidence of peripheral neural dysfunction and duration-related brainstem changes. Seventy-four tinnitus patients (101 ears) and 15 healthy controls (30 ears) with normal audiograms and preserved distortion-product otoacoustic emissions were enrolled; the tinnitus group was subdivided into acute (<6 months) and chronic (≥6 months) tinnitus. Click-evoked auditory brainstem responses were recorded from 45 to 90 dB nHL, and absolute wave latencies and amplitudes, interpeak latencies, intensity-response slopes, the wave V/I amplitude ratio, and wave V ABR growth ratio were analyzed using linear mixed-effects models. Pure-tone thresholds, wave V thresholds, and DPOAE measures did not differ across groups. Chronic tinnitus showed prolonged wave I latency at 55, 75, and 80 dB nHL, while both acute and chronic tinnitus showed reduced wave I amplitude at 45 dB nHL. Chronic tinnitus also showed a steeper wave V latency-intensity slope and a higher V/I ratio at 80 dB nHL, whereas interpeak latencies and wave V ABR growth ratio showed no robust group differences. These findings support selective ABR abnormalities in normal-audiogram tinnitus, centered on wave I changes, with additional suprathreshold brainstem alterations in chronic tinnitus.</p>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"481 ","pages":"109786"},"PeriodicalIF":3.0,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148864661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2026-08-25DOI: 10.1016/j.heares.2026.109785
Nick D van Huis, Niek J Versfeld, Cas Smits
{"title":"The band importance function for the Dutch digits-in-noise test: A computational derivation using human and automatic speech recognition data, including extended high frequencies.","authors":"Nick D van Huis, Niek J Versfeld, Cas Smits","doi":"10.1016/j.heares.2026.109785","DOIUrl":"https://doi.org/10.1016/j.heares.2026.109785","url":null,"abstract":"<p><p>The band importance function (BIF) quantifies the contribution of each frequency band to the intelligibility of speech and is a key element of the speech intelligibility index. The BIF depends on the type of speech material and speaker characteristics. Several BIFs exist, but they do not cover all test materials used in audiology. This study aimed to determine the BIF for the Dutch digits-in-noise (DIN) test, a widely used speech-in-noise measure. Twenty young adults with normal hearing completed a speech recognition task using Dutch DIN triplets presented at multiple signal-to-noise ratios (SNRs) and filtered according to one-third octave bands. The BIF was estimated using the computational method of Kates (2013), applying both digit and triplet scoring approaches. In addition, two automatic speech recognition (ASR) systems, Whisper and FADE, were used to generate comparative BIF estimates. Extended high frequencies (EHFs) were included to assess their contribution to intelligibility. The results showed that the BIF of the Dutch DIN test substantially deviates from other BIFs, particularly in the contribution of high frequencies. Approximately 9% of speech information was attributed to the EHFs. Validation showed improved prediction of DIN test speech recognition thresholds using the newly derived BIF compared to the SPIN BIF. Scoring method influenced band importance slightly, whereas ASR-based estimates did not match human-derived BIFs.</p>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"481 ","pages":"109785"},"PeriodicalIF":3.0,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148864592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2026-03-01Epub Date: 2025-12-17DOI: 10.1016/j.heares.2025.109509
Christoph Müller, Nico Bilic, Matthias Bornitz, Marcus Neudert, Thomas Zahnert, Martin Koch
{"title":"Relationship of sound transmission and ossicular chain mobility: investigations for the development of an intraoperative predictive surgical tool using a robotic approach","authors":"Christoph Müller, Nico Bilic, Matthias Bornitz, Marcus Neudert, Thomas Zahnert, Martin Koch","doi":"10.1016/j.heares.2025.109509","DOIUrl":"10.1016/j.heares.2025.109509","url":null,"abstract":"<div><div>Intraoperative assessment of ossicular chain mobility remains challenging in reconstructive middle-ear surgery because conventional palpation is subjective. To better predict the postoperative air–bone gap (ABG) and guide decisions on whether revision surgery may be beneficial for hearing restoration, a more refined intraoperative assessment that differentiates the degree of ossicular chain mobility reduction is required. In this ex vivo study, we evaluated whether quasi-static stiffness measurements can predict sound transmission.</div><div>Twelve human cadaveric temporal bones were mounted on a robotic setup in which a force-sensing needle robotically executed a standardized palpation sequence along a predefined trajectory, enabling calculation of direction-specific stiffness metrics. Stepwise artificial stiffening of the annular ligament, the stapes superstructure and the surrounding anatomical spaces of the tympanic cavity with thin layers of UV-curable resin produced graded sound transmission losses across up to five increments (for a total of ≈20–30 dB). The derived stiffness metrics tracked this decline only partially and anisotropically, with changes corresponding to <10 dB equivalents in specific probing directions. Nevertheless, binomial generalized linear models identified stiffness thresholds that discriminated among clinically relevant ABG categories (<10 dB, 10–20 dB, >20 dB). Similar trends were observed in three additional specimens with an opened incudostapedial joint. These finding demonstrate that quantitative force measurements or simplified surgical tools fitted to specific force thresholds could potentially provide surgeons with an intraoperative evaluation support tool.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"473 ","pages":"Article 109509"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2026-03-01Epub Date: 2026-02-10DOI: 10.1016/j.heares.2026.109572
Evangelia Tserga , Ivan A. Lopez , Barbara Canlon
{"title":"Circadian control of the peripheral vestibular organs in rodents and humans","authors":"Evangelia Tserga , Ivan A. Lopez , Barbara Canlon","doi":"10.1016/j.heares.2026.109572","DOIUrl":"10.1016/j.heares.2026.109572","url":null,"abstract":"<div><div>Circadian rhythms are fundamental for maintaining physiological homeostasis, influencing processes such as sleep-wake cycles, metabolism, and hormonal regulation. The suprachiasmatic nucleus (SCN), the primary pacemaker in the brain, is necessary to maintain behavioral circadian rhythms and to synchronize peripheral clocks throughout the body in mammals. The vestibular system, responsible for balance and spatial orientation, has been implicated in circadian regulation, yet its intrinsic clock machinery remains unexplored. Previous studies suggest vestibular input influences circadian rhythms, as evidenced by altered locomotor activity and temperature control in animals with vestibular dysfunction. Additionally, vestibular disorders in humans display time-dependent patterns, further supporting a vestibular-circadian interaction. Our study investigates the presence of an autonomous circadian clock in the peripheral vestibular organs (semicircular canals SCC, saccule, utricle and vestibular ganglia) by assessing core clock gene and protein expression in vestibular structures of mice and humans. Using PERIOD2::LUCIFERASE (PER2::LUC) bioluminescence assays from mouse tissues, we observed self-sustained oscillations in SCC, saccule, and utricle, with differential amplitudes and phase relationships. RNA scope (<em>Bmal1</em>) confirmed the rhythmic expression in the peripheral vestibular organ from mice, corroborating their functional circadian regulation. Furthermore, we explored the impact of cisplatin, a chemotherapeutic agent, on vestibular clock rhythms. Cisplatin administration disrupts PER2 oscillations in vestibular explants in a time-dependent manner, mirroring the cochlear findings where the day or night timing of drug delivery modulates drug response. Our findings provide the first direct evidence of a clock within the peripheral vestibular organ of rodents and humans, highlighting its potential role in modulating vestibular function and responses to pharmacological interventions. These findings suggest that vestibular disorders may follow a daily pattern, which could help explain why symptoms worsen or improve at different times of the day. This could lead to better treatment strategies for millions of people affected by vestibular dysfunction. Demonstrating that the chemotherapy drug cisplatin disrupts vestibular rhythms in a time-dependent manner, suggests that administering drugs at the right time of day could minimize side effects like dizziness and nausea while maximizing effectiveness. These results underscore the importance of considering circadian timing in vestibular research and therapeutic strategies.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"473 ","pages":"Article 109572"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2026-03-01Epub Date: 2026-02-18DOI: 10.1016/j.heares.2026.109575
John J. Guinan Jr. , Hui Nam
{"title":"Bias-tone suppression of the auditory-nerve initial-peak (ANIP) response supports the hypothesis that ANIP is driven by cortilymph-organ-of-Corti-core longitudinal motion","authors":"John J. Guinan Jr. , Hui Nam","doi":"10.1016/j.heares.2026.109575","DOIUrl":"10.1016/j.heares.2026.109575","url":null,"abstract":"<div><div>The auditory-nerve initial peak (ANIP) is the earliest response from moderate-to-high-level clicks in cat auditory-nerve type-1 fibers with characteristic frequencies (CFs) <3 kHz. ANIP is inhibited by medial-olivocochlear-efferent stimulation, and is suppressed when low-frequency (50 Hz) “bias” tones place the outer-hair-cell (OHC) mechano-electric-transduction (MET) function into low-slope, saturating edges. These properties show that ANIP emanates from OHC motility. Unexpectedly, the bias-tone phase that produces the most suppression (the major-suppression phase, MSP) is opposite for ANIP versus for low-level click or tone responses. We present data showing this difference, plus this hypothesis for its origin: Low-level responses take several cycles to build up and their gain is set by the local MET-function slope; their MSP is when the bias tone quasi-statically deflects the MET operating point to its nearest low-slope, saturation edge. In contrast, ANIP is the first half-cycle response from higher-level clicks, and requires OHC stereocilia deflection only in one direction. When a bias tone places the OHC-MET operating point at its nearest saturating edge, a rarefaction-click’s unidirectional initial stereocilia deflection is <em>away from</em> this saturation, enabling a large traverse of the MET-function high-slope, high-gain region. The bias-tone level necessary to reach criterion suppression was higher for ANIP than for low-level clicks, which indicates that ANIP suppression occurred more basal where BM stiffness is higher. We hypothesize that ANIP is driven by apically-directed transverse motion of cortilymph and nearby organ-of-Corti-core tissue, i.e., is separate from the traveling-wave. Waxing-and-waning click responses also show that traveling waves are not simple, unitary waves.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"473 ","pages":"Article 109575"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147270843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}