Publications using TDT

Introduction: Hearing is critical for communication and clinical evidence suggests that hearing loss can lead to poorer mental well-being including social isolation, anxiety, depression, and cognitive decline. Deaf animal models offer opportunities to investigate the impact of hearing loss on behavioral correlates of mental health while controlling for genetic variability and shared etiological factors such as environmental stressors, aging, and metabolic diseases. We previously showed that conditional deletion of Ebf1 in the inner ear causes deafness. We hypothesize that otic-specific Ebf1 knockout (KO) mice recapitulate neurobehavioral alterations experienced in congenital deafness. Methods: Slc26a9P2A-Cre and Ebf1 floxed mice were crossed previously to generate the otic-specific Ebf1 conditional KO. We measured auditory brainstem response and behavior in groups of otic-specific Ebf1 conditional KO mice and Cre-negative littermate controls (WT). We performed behavioral tests including elevated plus maze, acoustic startle, locomotor activity, forced swim, and Y-maze. Results: We found that the KO mice spend significantly less time than WT mice in the open arms of the elevated plus maze. KO mice also show significantly increased latency to enter the open arms. Acoustic startle response was decreased in KO mice vs. WT controls and pre-pulse inhibition was also reduced in the KO, consistent with elevated hearing thresholds. We found no significant differences in exploratory behavior, forced swim immobility time, or other behavioral measures examined. Conclusions: Our findings demonstrate that deaf otic-specific KO mice are indeed a model for the study of effects of hearing loss on clinically relevant behavioral correlates. Our results provide new empirical evidence that hearing loss contributes to anxiety, which is consistent with clinical evidence that anxiety is associated with hearing loss in older adults.

Peripheral nerve injuries lead to diminished function and pain via nociplastic phenomena. We propose a new strategy called directed functional reinnervation, in which nerves are reassigned to new peripheral targets with the intention of altering circuit function. Here, we redirect the saphenous sensory nerve into a skeletal muscle graft to curb nociplasticity and provide benign sensations or useful inputs for prosthetic applications. Electrophysiological functional characterization demonstrated robust afferent responses to mechanical stimulation of the muscle. Immunofluorescence staining indicated widespread innervation of various synapses within the muscle graft. With immediate graft placement, the injured nerve's dorsal root ganglia revealed comparable levels of nociceptive markers to uninjured nerves, suggesting a molecular basis for the prevention of pain sensitization. These findings contribute to the mechanism by which skeletal muscle grafts alleviate neuropathic pain and can be used as a sensory transmitter in conjunction with neural interfaces.

The Mongolian gerbil is a common model organism for studying the neural and behavioral mechanisms of binaural and spatial hearing, largely because of its ability to hear lower frequencies better than other rodents and thus utilize both interaural time and level difference cues for sound localization. Prior spatial hearing studies in gerbils have relied on operant conditioning paradigms, requiring large amounts of time-consuming training and testing on multiple different tasks needed to make a comprehensive assessment of spatial hearing ability (including temporal processing, spatial acuity and spatial unmasking). This limits the ability of researchers to thoroughly assess behavioral performance in a population of animals. In this study, we used the prepulse inhibition of the acoustic startle reflex (PPI) to extensively assess spatial hearing and temporal processing abilities in a population of gerbils of both sexes. Results show that gerbils inhibit a startle response to a brief loud sound based on prepulse acoustical cues consisting of a 1) temporal gap in ongoing sounds, 2) change in sound source location, and 3) target sound in the presence of a masker. In each test, the magnitude of the suppression of startle increased monotonically as a function of the magnitude of the acoustical prepulse, not unlike a psychometric function, from which threshold performance could be measured. Thresholds in the gerbils in each task measured using PPI matched those acquired using operant conditioning methods.

The mammillary body (MB) has traditionally been regarded as a relay station for the hippocampus and plays a pivotal role in the Papez circuit. However, its molecular and cellular organization remains inadequately characterized. This study focuses on the horizontally symmetrically distributed neurotensin (Nts)-expressing and nitric oxide synthase 1 (Nos1)-expressing neurons in the MB, demonstrating that Grik4 (encoding a high-affinity kainate receptor subunit) underlies their distinct electrophysiological properties. Within neural circuits, Nts and Nos1 neurons receive excitatory inputs from the ventral subiculum and send parallel excitatory projections to the dorsomedial and ventrolateral subdivisions of the anteroventral thalamus (AV). These 2 cell type-specific circuits are essential for working memory and exhibit selective activation during the maintenance phase with a marked temporal difference. Together, our findings establish a direct link from molecular identity to circuit architecture and cognitive processing by demonstrating that molecularly distinct Nts and Nos1 neurons constitute differential circuits with convergent inputs, divergent outputs, and dissociable roles in working memory maintenance. This work thus reveals a fundamental cross-scale organizational principle—molecule, cell, circuit, function—within the MB.

The mismatch response (MMR) is a critical neural indicator of the discrimination of speech contrasts. Previous research has demonstrated that language experience can affect MMRs: speech contrasts in one’s native language differ from nonnative speech contrasts. This effect is observed as early as 11–12 months, but not at 6–7 months, reflective of early learning of speech sounds. Yet, many challenges remain when using MMRs to study speech learning in infants, including prolonged recording time, inefficient use of data, and a lack of reconciliation of MMR recorded using different technologies (i.e., EEG vs. magnetoencephalography [MEG]). Using an improved recording paradigm and analysis approach, the current study addressed these challenges by examining (1) whether MEG-MMR is linked to the well-established EEG-MMR in the same adults and (2) whether our methods capture the difference in MEG-MMR between native and nonnative speech contrasts in adults and (3) in older infants. Results from 18 adults with simultaneous M/EEG demonstrated a high correlation between the MEG-MMR and the EEG-MMR. Additionally, MEG-MMRs to native speech contrasts were different from ones to nonnative speech contrasts, replicating spatiotemporal patterns documented in the existing literature. Finally, we replicated this effect in the MEG-MMR in 14 infants aged between 9 and 14 months using the same methods. These findings validate our new methodologies with less than 15 mins of recording time for acquiring and analyzing speech-related MMRs across ages, paving the way for studying early language development, and improving early detection of language-related disorders.

Physical exercise acutely improves hippocampus-dependent memory. Whereas animal studies have offered cellular- and synaptic-level accounts of these effects, human neuroimaging studies show that exercise improves hippocampal-cortical connectivity at the macroscale level. However, the neurophysiological basis of exercise-induced effects on hippocampal-cortical circuits remains unknown. Experimental evidence supports the idea that hippocampal sharp wave-ripples (SWR) play a critical role in learning and memory. Coupling between SWRs in the hippocampus and neocortex may reflect modulations in inter-regional connectivity required by mnemonic processes. Here, we examine the hypothesis that exercise modulates hippocampal-cortical ripple dynamics in the human brain. We performed intracranial recordings in epilepsy patients undergoing pre-surgical evaluation, during awake resting state, before and after an exercise session. Exercise increased ripple rate in the hippocampus. Exercise also enhanced the coupling and phase-synchrony between cortical ripples in the limbic and the default mode (DM) cortical networks and hippocampal SWRs. Further, a higher heart rate during exercise, reflecting exercise intensity, was related to a subsequent increase in resting state ripples across specific cortical networks, including the DM network. These results offer the first direct evidence that a single exercise session elicits changes in ripple events, a well-established neurophysiological marker of mnemonic processing. The characterisation and anatomical distribution of the described modulation points to hippocampal ripples as a potential mechanism by which exercise elicits its reported short-term effects in cognition.

In everyday settings, information processing depends on attentional focus, available cognitive resources, and stimulus characteristics such as its valence. Despite insights from laboratory studies, multisensory information processing in complex, realistic environments remains poorly understood. Using whole-head magnetoencephalography and eye tracking in a driving simulation, we addressed two research questions: (1) What are the distinct signatures of (socio-)emotional speech processing and visuo-spatial cognition in the dual task of driving and listening and (2) is information processing co-modulated by valence of speech and workload? We hypothesised two antagonistic processing modes: A top-down guided mode for (socio-)emotional speech processing and a bottom-up stimulus-driven mode for visuo-spatial cognition under high workload. A third mode was proposed to regulate emotional interference during driving under high visuo-spatial load and limited cognitive capacity. Its involvement is hypothesised to be co-modulated by valence and workload. Spatial clustering of oscillatory source activity supported the hypotheses: During emotional compared with neutral speech, parietal beta-band power increased, which likely supported processes related to predictive listening and socio-emotional cognition. In this top-down guided mode, driving-related activity decreased, as indicated by greater parietal alpha- and reduced gamma-band power. During high visuo-spatial workload, linked to the bottom-up stimulus-driven mode, gamma-band power increased in motor and orbitofrontal cortices, whereas beta-band power decreased in motor and temporo-parietal regions. Moreover, increased pupil dilation and decreased gaze dispersion were associated with this bottom-up stimulus-driven mode and visuo-spatial cognitive demands. Multivariate pattern analyses identified the third regulatory mode reflected in fronto-temporal gamma-band oscillations. It was co-modulated by valence and workload: Under low workload drives, gamma-band activity increased for negative compared with positive speech, pointing to the recruitment of inhibitory control processes. Under high workload drives with heightened visuo-spatial demands, gamma-band activity increased for positive speech, but decreased for negative speech, suggesting reduced cognitive resources and impaired control. To conclude, we found converging evidence of distinct signatures for (socio-)emotional speech, visuo-spatial cognition, and interference regulation in naturalistic multisensory environments. We propose that the top-down guided mode represents anticipatory listening and socio-emotional cognition, whereas the bottom-up stimulus-driven mode reflects the allocation of resources to driving-related spatial and sensorimotor processing but also cognitive strain under heightened task demands. Fronto-temporal gamma oscillations likely enable flexible up- and down-regulation of emotional speech processing in response to potential interference in complex, naturalistic environments.

The non-rapid-eye movement (NREM) sleep power spectrum is composed of rhythmic and arrhythmic components, respectively associated with brain rhythms and scale-free dynamics. Both components are hypothesized to represent distinct processes underlying sleep-dependent memory consolidation as well as other brain complex processes. Recent advancements in spectral parametrization techniques and the use of multifractal models have enabled new insights into these components and their connection to brain networks. Aging impacts NREM sleep oscillations, but no animal studies considered the impact of age on rhythmic and arrhythmic components. In this study, we assessed the effects of age on the power spectrum and its two components using local field potential recordings in mice. We recorded across the cerebral cortex and within the hippocampus—a central brain hub involved in NREM sleep-dependent cognitive processing. Ten younger (7.6 months) and eleven older (15.7 months) C57BL/6 J male and female mice were continuously recorded over a 24-hour period. We extracted the NREM sleep standard and rhythmic spectra, controlled for scale-free activity, and estimated multifractal arrhythmic properties during NREM sleep using the Wavelet Leader and Bootstrap based MultiFractal analysis toolbox. Older mice showed specific alterations in both components compared to younger animals: reduced rhythmic gamma power in the anterior cortex, greater regional differentiation of scaling exponents, and higher multifractal dispersion of the arrhythmic component in the hippocampus. These findings demonstrate that aging alters rhythmic and arrhythmic properties of NREM sleep in distinct brain regions, suggesting that both contribute to age-related changes in sleep-dependent cognition.

The clinical use of alternating current stimulation (ACS) has been confounded by heterogeneity in patient responses. Optimization of this treatment requires understanding the dependence of neuronal responses on ACS parameters. We sought to characterize neuronal responses across varying ACS frequencies and amplitudes and assess the extent to which changes in neuronal activity persist beyond the cessation of the stimulation, thereby informing ACS optimization pathways and evaluating the potential for sustained neuromodulation. We delivered subcutaneous ACS while recording intracortical electrophysiological activity in adult rats. We applied ACS for 1 or 20 minutes and analyzed ensuing spiking activity, power spectra, and low-frequency to high-frequency phase–amplitude coupling (LF-HF PAC). Both durations of ACS elicited a modulation of firing patterns (either in rate or entrainment) in most neurons, in a stimulation frequency- and amplitude-dependent manner. Changes in firing rate were more frequent, albeit modest, whereas changes in entrainment were rarer, but pronounced. Increasing ACS amplitude or frequency increased the degree of entrainment. Further, entrainment changes persisted beyond the 20-minute ACS, at half their online level. Neuronal power and LF-HF PAC increased proximal to excited, but decreased near suppressed neurons. Neuronal entrainment was observed alongside decreased power and LF-HF PAC. The prominent entrainment response to prolonged high-frequency ACS observed here supports the potential of ACS for facilitating signal integration and promoting functional reorganization via spike timing-dependent plasticity. In turn, we found broader temporal windows of excitation under low ACS frequencies engendered greater variability in spike timing, which may be utilized to reduce hypersynchronous or task-irrelevant activity.

Background: Electrical stimulation targeting the motor thalamus (Mthal) represents an emerging strategy for regulating motor cortical activity patterns, however the fundamental mechanisms and optimal stimulation configurations are not well established. Objective: To characterize how burst Mthal stimulation modulates cortical activity and to identify stimulation parameters that maximize cortical co-firing via thalamocortical rebound mechanisms. Methods: We conducted acute electrophysiological experiments in anesthetized rats using Mthal stimulation with systematically manipulated burst stimulation parameters (i.e., number of pulses and pulse width) in the low-frequency band (1-8 Hz) modulation cycle. Cortical responses across large areas covering primary and secondary motor cortex were recorded. Additionally, intracortical recordings were performed for detailed spike activity monitoring during stimulation. Cortical activity patterns in local field potentials and spike activity were analyzed to quantify the effects of Mthal stimulation on motor cortex. Computational thalamocortical circuit models were employed to explore the mechanistic basis of frequency-selective modulation effects. Results: Burst Mthal stimulation elicited tunable cortical excitation, with optimal modulation achieved at 3-4 Hz. This preferred frequency corresponded to the natural rebound timing of thalamocortical (TC) cells and generated maximal cortical co-firing and synchronization. Higher stimulation frequencies (e.g., 8 Hz) resulted in suppressed and diminished responses. Computational modeling further validated that the cellular mechanism of the TC cell rebound excitation leads to frequency-dependent cortical modulation. Conclusion: Burst Mthal stimulation demonstrates frequency-selective modulation of cortical network excitability, with 3-4 Hz protocols providing optimal enhancement of synchronized activity through exploitation of thalamocortical rebound dynamics. These results establish motor thalamic stimulation as a promising and efficient methodology for precise cortical network control and offer mechanistic foundations for developing therapeutic neuromodulation interventions aimed at motor system rehabilitation.

In adults with acquired hearing loss, cortical reorganization and cross‐modal plasticity critically influence the timing and outcomes of cochlear implantation. This study examined the effects of 2 weeks of bilateral auditory deprivation—induced by intense broadband noise—on the structure and gene expression in the primary auditory (A1) and visual (V1) cortices of adult rats. The results revealed that the total neuronal counts in both the A1 and V1 remained unchanged compared to controls. Morphological analysis showed no significant change in mature dendritic spine density in either region, but immature spine density was significantly reduced in the V1 cortex. Ultrastructural examination demonstrated notable synaptic alterations in the A1 cortex, including significant reductions in postsynaptic density (PSD) length, thickness, area, and synaptic vesicle number—changes that were not observed in the V1 cortex. Transcriptomic profiling indicated a region‐specific response, with 197 differentially expressed genes (DEGs) in the A1 cortex, compared to a broader alteration of 545 DEGs in the V1 cortex, which were significantly involved in neuronal signaling and synaptic transmission. These findings demonstrate that auditory deprivation induces distinct molecular and synaptic remodeling in the A1 and V1 cortices, identifying neuronal plasticity and synaptic regulation as central mechanisms for cross‐modal reorganization in the adult brain.

Background DFNB16, the second most common genetic cause of hearing loss, is caused by mutations of the STRC gene encoding stereocilin, a protein essential for the effective functioning of outer hair cells (OHCs) as cochlear amplifiers. Strc −/− mice, which lack stereocilin, display severe to profound deafness and constitute a relevant preclinical model for DFNB16. Methods Using Strc − / − mice, we developed a gene therapy strategy based on the use of dual AAV9‐PHP.eB vectors to deliver the full‐length Strc cDNA. Therapeutic efficacy was assessed by evaluating stereocilin expression, OHC bundle architecture, and their attachment to the tectorial membrane, together with functional recovery using distortion product otoacoustic emissions (DPOAEs), auditory brainstem responses (ABR) measurements and Go/No‐Go behavioral testing with psychometric analysis. Results Dual‐AAV–mediated Strc gene delivery restored stereocilin expression, OHC bundle architecture and their attachment to the tectorial membrane, leading to the recovery of cochlear amplification and hearing to near normal thresholds, as confirmed by distortion product otoacoustic emission (DPOAE) and auditory brainstem response measurements. Behavioural assessment showed that treated Strc −/− mice regained normal frequency discrimination, indicating a restoration of higher‐order auditory processing, up to 100 days post‐treatment. Conclusion These findings provide the first proof‐of‐principle that peripheral gene therapy can restore OHC function, cochlear amplification and central auditory perception in a DFNB16 model. Key points Dual AAV‐mediated gene delivery restored peripheral hearing in a DFNB16 preclinical mouse model. The same treatment also restored central auditory processing. AAV‐mediated gene therapy represents a promising curative strategy for DFNB16. These results reinforce the translational potential for treating human genetic deafness.

Bilateral cochlear implant (BiCI) users do not perform as well as typical hearing listeners when discriminating the direction of sound motion. This is likely due to the lack of synchronization between two independently operating sound processors. The use of bilaterally linked processors can improve the timing of electrical stimulation across the ears. However, these improvements are potentially counteracted by spectral peak-picking in sound coding strategies that may activate different electrodes across the ears, thereby reducing the fidelity of the binaural cues that BiCI users rely on for sound localization. To improve interaural synchrony, a bilateral peak-picking strategy that guarantees coordinated stimulation across the ears was developed and tested using the CCi-MOBILE, a bilaterally linked research processor. The auditory motion tracking abilities of nine BiCI users were measured using the bilateral peak-picking strategy and compared to performance with commercially available, unsynchronized processors. Results showed no effect of bilateral peak-picking. However, a small benefit was observed when tracking the range of motion of a sound when listening with bilateral synchronization which appears to be due to reduced interaural level difference changes with auditory motion. These findings suggest that dynamic auditory perception with BiCI may likely need bilaterally-synchronized hardware.

Transcranial Focused Ultrasound Stimulation (tFUS) is a promising non-invasive technique capable of modulating brain activity with high spatial precision. However, its efficacy for seizure suppression requires further exploration. This study aims to address whether tFUS of white matter can suppress seizures non-invasively. Repeated injections of a 4-Aminopyridine (4-AP) cocktail into the right somatosensory cortex (S1) induced cortical seizures in male rats under anesthesia with recording of both EEG and intracranial signals. Approximately one hour of tFUS was applied to the corpus callosum (CC) using a 128-element random-array transducer with 20 ms pulse duration, 1 Hz pulse repetition frequency, 2% duty cycle, and ~127 kPa pressure. Another 2-3 hours were used to assess post-stimulation effects. Seizure duration, seizure count, percent time in seizure, and inter-seizure interval were compared to a sham control for quantifying efficacy. The absolute frequency power, asymmetry index (AI), and phase lag index (PLI) were calculated to analyze brain activity changes induced by tFUS. CC tFUS can significantly reduce percent time in seizure, seizure duration, and seizure count, as well as increase inter-seizure interval. These effects extended up to 2 hours post-stimulation. We also observed a decrease in absolute power of the beta band and changes in the brain network, as evidenced by a decrease in synchronization and an improvement in interhemispheric balance. Our study is the first to show that white matter tFUS can significantly suppress seizures with a lasting post stimulation effect, potentially providing a safer alternative for drug-resistant epilepsy patients.

Identification of speech sounds is influenced by spectral contrast effects (SCEs), the perceptual magnification of spectral differences between successive sounds. SCEs result in the categorization of a target sound being biased away from spectral properties in the preceding acoustic context. Given remarkable consistency in the magnitudes of these contrast effects within the same frequency region [Stilp (2019) J. Acoust. Soc. Am. 146(2), 1503–1517], it was hypothesized that they would also show stable relationships across different frequency regions. In this study, normal-hearing listeners' phoneme categorization and contrast effects were assessed where phonetic contrasts were driven by changes in low-frequency F1 (“big”-“beg” continuum), mid-frequency F3 (“dot”-“got”), or high-frequency frication spectrum regions (“sheet”-“seat”). On each trial, listeners heard a precursor sentence that was filtered to emphasize energy in the lower or higher range within one of these frequency regions, followed by a target word that hinged on the frequency region that was filtered. Results showed that SCEs influenced categorization in each frequency region, as expected. However, effect magnitudes were not correlated with each other across frequency regions within or across two participant samples. This clarifies perception-in-context on a broader scale as the influence of spectral contrast is independent across different frequency regions.

It is widely known that users of cochlear implants (CIs) often show deficits in binaural hearing. In particular, interaural time difference (ITD) discrimination tends to be substantially worse in CI users. However, only very few studies have investigated how CI stimulation affects the “precedence effect” (PE), and how this might be affected by abnormal hearing experience during development. We performed behavioral experiments to measure temporal weighting functions (TWFs) to quantify the PE in three different cohorts of rats: normally hearing (NH) acoustically stimulated, neonatally deafened (ND) CI-stimulated, and adult deafened (AD) CI-stimulated animals. Lateralization responses were recorded to bursts of eight stimulus pulses in which the ITD of each pulse varied independently, and probit analysis revealed the perceptual weight of each pulse. The NH and ND-CI cohorts were tested at 50, 300, and 900 pps; the AD-CI animals were tested only at 300 pps. The NH animals show a pronounced “onset dominance” at higher pulse rates, that is, the weighting of the first pulse was much larger than for subsequent pulses, exactly as one would expect given previous studies on human listeners. In contrast, the TWFs for the ND-CI and AD-CI animals were much flatter, with a reduction of onset dominance by ∼75%, especially for higher pulse rates. Since neither of our CI cohorts had any experience of reverberation in their electric hearing, we interpret these results to indicate that the PE may require domain-specific experience to develop.

Background: Cisplatin is a widely used chemotherapeutic agent, but its clinical application is limited by serious ototoxic side effects, including hearing loss, tinnitus, and vertigo. Inflammation is now recognized as a significant contributor to cisplatin-induced hearing loss, but the upstream regulators remain largely undefined. This study aimed to identify novel regulators of cisplatin-induced ototoxicity through CRISPR-Cas9 screening and to determine the role of growth arrest and DNA damage-inducible alpha (GADD45A) in cochlear inflammation and hearing loss. Methods: To identify upstream regulators of cisplatin-induced ototoxicity, a CRISPR-Cas9-based loss-of-function screen was first performed in OC1 cells. Following the identification of Gadd45a as a candidate gene, its effects on cisplatin-induced cytotoxicity were evaluated using cell viability assays, flow cytometry, and TUNEL staining. Integrated transcriptomic and proteomic analyses were subsequently conducted to elucidate the downstream molecular mechanisms. Finally, the protective role of Gadd45a inhibition was validated in vivo through siRNA delivery into the posterior semicircular canal and in Gadd45a conditional knockout (cKO) mice. Results: Gadd45a knockout significantly inhibited cisplatin-induced cell death in the OC1 cell line while simultaneously enhancing autophagy signaling. Transcriptomic profiling revealed a marked downregulation of the expression of C-X-C motif chemokine ligand (CXCL) family cytokines following Gadd45a loss, which was further supported by proteomic analysis of culture supernatants. Mechanistically, Gadd45a knockout specifically inhibited nuclear factor κB subunit 1 (NF-κB1) but not RELA proto-oncogene, NF-κB subunit (RELA). Immunofluorescence staining demonstrated that Gadd45a knockout inhibited the nuclear translocation of the NF-κB1 protein, and subsequent studies revealed that the NF-κB1 protein was degraded through the lysosomal pathway. In vivo, both si-Gadd45a injection into the semicircular canal and the knockout of Gadd45a effectively attenuated cisplatin-induced ototoxicity. Conclusions: This study identifies GADD45A as a key regulator of cisplatin ototoxicity and links the balance between apoptosis and autophagy with NF-κB1-CXCL-mediated inflammation. Targeted inhibition of GADD45A signaling may represent a promising therapeutic strategy to prevent hearing loss in patients receiving cisplatin chemotherapy.

Background Usher syndrome (USH) is an autosomal recessive disorder characterized by hearing loss, retinitis pigmentosa, and variable vestibular dysfunction. USH2A is one of the causative genes of USH. This study is aimed at exploring the mechanism of hearing loss induced by USH2A gene knockout. Method USH2A knockout (Ush2a −/− ) mice were used, and auditory brainstem response testing was performed on WT, Ush2a −/− , and Ush2a +/− mice. Then, the cochlea tissues were used to carry out immunofluorescence staining, hematoxylin and eosin (H&E) staining, and scanning electron microscopy (SEM). The mRNA expressions were detected by RT‐qPCR. Finally, the differentially expressed genes (DEGs) in cochlear tissues of Ush2a −/− and WT mice were identified by transcriptome sequencing. Results Compared to WT mice, Ush2a −/− and Ush2a +/− mice exhibited moderate‐to‐severe nonprogressive hearing loss, with more pronounced deficits at low (4 kHz) and high (32/24 kHz) frequencies. HE staining and immunofluorescence staining showed that the modiolus, stria vascularis, basilar membrane, and the number of inner hair cells and outer hair cells (OHCs) in USH2A knockout mice have not changed. However, SEM results showed that severe stereociliary collapse was evident in OHCs of the Ush2a −/− group. In addition, through transcriptomic analysis, 3632 upregulated genes and 2921 downregulated genes were obtained in the Ush2a −/− mice. Among these DEGs, the most DEGs associated with hearing loss were Scn2a, Shank2, Bsn, Fcer1g, Prkce, Tgfb1, and Irf7. Conclusion This study demonstrates that USH2A deficiency disrupts auditory function through stereociliary instability and dysregulation of genes critical for synaptic transmission and cytoskeletal dynamics.