Auditory cortex

The central tendency bias, or contraction bias, is a phenomenon where the judgment of the magnitude of items held in working memory appears to be biased toward the average of past observations. It is assumed to be an optimal strategy by the brain and commonly thought of as an expression of the brain's ability to learn the statistical structure of sensory input. On the other hand, recency biases such as serial dependence are also commonly observed and are thought to reflect the content of working memory. Recent results from an auditory delayed comparison task in rats suggest that both biases may be more related than previously thought: when the posterior parietal cortex (PPC) was silenced, both short-term and contraction biases were reduced...

OBJECTIVE: To explore the changes in the cerebral microstructure of patients with noise-induced hearing loss (NIHL) using diffusion tensor imaging (DTI). METHOD: Overall, 122 patients with NIHL (mild [MP, n = 79], relatively severe patients [including moderate and severe; RSP, n = 32], and undetermined [lost to follow-up, n = 11]) and 84 healthy controls (HCs) were enrolled. All clinical data, including age, education level, hearing threshold, occupation type, noise exposure time, and some scale scores (including the Mini-Mental State Examination [MMSE], tinnitus handicap inventory [THI], and Hamilton Anxiety Scale [HAMA]), were collected and analyzed...

UNLABELLED: Hearing is an active process in which listeners must detect and identify sounds, segregate and discriminate stimulus features, and extract their behavioral relevance. Adaptive changes in sound detection can emerge rapidly, during sudden shifts in acoustic or environmental context, or more slowly as a result of practice. Although we know that context- and learning-dependent changes in the spectral and temporal sensitivity of auditory cortical neurons support many aspects of flexible listening, the contribution of subcortical auditory regions to this process is less understood...

Schizophrenia is a complex neuropsychiatric disorder with significant morbidity. Treatment options that address the spectrum of symptoms are limited, highlighting the need for innovative therapeutic approaches. Gamma Entrainment Using Sensory Stimulation (GENUS) is an emerging treatment for neuropsychiatric disorders that uses sensory stimulation to entrain impaired oscillatory network activity and restore brain function. Aberrant oscillatory activity often underlies the symptoms experienced by patients with schizophrenia...

The auditory cortex is the source of descending connections providing contextual feedback for auditory signal processing at almost all levels of the lemniscal auditory pathway. Such feedback is essential for cognitive processing. It is likely that corticofugal pathways are degraded with aging, becoming important players in age-related hearing loss and, by extension, in cognitive decline. We are testing the hypothesis that surface, epidural stimulation of the auditory cortex during aging may regulate the activity of corticofugal pathways, resulting in modulation of central and peripheral traits of auditory aging...

BACKGROUND: Cortical thickness (CT) alterations, mismatch negativity (MMN) reductions, and cognitive deficits are robust findings in first-episode psychosis (FEP). However, most studies focused on medicated patients, leaving gaps in our understanding of the interrelationships between CT, MMN, neurocognition, and psychosocial functioning in unmedicated FEP. This study aimed to employ multiple mediation analysis to investigate potential pathways among these variables in unmedicated drug-naïve FEP...

Neuroimaging studies have shown that the neural representation of imagery is closely related to the perception modality; however, the undeniable different experiences between perception and imagery indicate that there are obvious neural mechanism differences between them, which cannot be explained by the simple theory that imagery is a form of weak perception. Considering the importance of functional integration of brain regions in neural activities, we conducted correlation analysis of neural activity in brain regions jointly activated by auditory imagery and perception, and then brain functional connectivity (FC) networks were obtained with a consistent structure...

INTRODUCTION: Subjective tinnitus, the perception of sound without an external acoustic source, is often subsequent to noise-induced hearing loss or ototoxic medications. The condition is believed to result from neuroplastic alterations in the auditory centers, characterized by heightened spontaneous neural activities and increased synchrony due to an imbalance between excitation and inhibition. However, the role of the thalamic reticular nucleus (TRN), a structure composed exclusively of GABAergic neurons involved in thalamocortical oscillations, in the pathogenesis of tinnitus remains largely unexplored...

Individuals with methamphetamine use disorder (MUD) often experience anxiety and depressive symptoms during abstinence, which can worsen the likelihood of relapse. Thus, it is essential to understand the neuro-mechanism behind methamphetamine use and its associated emotional withdrawal symptoms in order to develop effective clinical strategies. This study aimed to evaluate associations between emotional withdrawal symptoms and structural covariance networks (SCNs) based on cortical thickness (CTh) across the brain...

According to the predictive processing framework, perception emerges from the reciprocal exchange of predictions and prediction errors (PE) between hierarchically organized neural circuits. The nonlemniscal division of the inferior colliculus (IC) is the earliest source of auditory PE signals, but their neuronal generators, properties and functional relevance have remained mostly undefined. We recorded single-unit mismatch responses to auditory oddball stimulation at different intensities, together with activity evoked by two sequences of alternating tones to control frequency-specific effects...

Autism spectrum disorder (ASD) is often associated with social communication impairments and specific sound processing deficits, for example problems in following speech in noisy environments. To investigate underlying neuronal processing defects located in the auditory neocortex (AC), we performed two-photon Ca2+ imaging in FMR1 ( Fragile X Messenger Ribonucleoprotein 1 ) knockout (KO) mice, a model for Fragile-X-Syndrome (FXS), the most common cause of hereditary ASD in humans. For primary AC (A1) and the anterior auditory field (AAF), topographic frequency representation was less ordered compared to control animals...

Tinnitus is a health condition that affects a large population. Clinical diagnosis and treatment have been developed for treating tinnitus for years. However, there are still limitations because researchers have yet to elucidate the mechanisms underlying how tinnitus neural signals develop in brain structures. Abnormal neural interactions among the brain areas are considered to play an important role in tinnitus generation. Researchers have been studying neural activities in the auditory brain structures, including the dorsal cochlear nucleus (DCN), inferior colliculus (IC), and auditory cortex (AC), to seek a better understanding of the information flow among these brain regions, especially in comparison with both health and tinnitus conditions...

Performance during perceptual decision-making exhibits an inverted-U relationship with arousal, but the underlying network mechanisms remain unclear. Here, we recorded from auditory cortex (A1) of behaving mice during passive tone presentation, while tracking arousal via pupillometry. We found that tone discriminability in A1 ensembles was optimal at intermediate arousal, revealing a population-level neural correlate of the inverted-U relationship. We explained this arousal-dependent coding using a spiking network model with a clustered architecture...

UNLABELLED: Prior lesion, noninvasive-imaging, and intracranial-electroencephalography (iEEG) studies have documented hierarchical, parallel, and distributed characteristics of human speech processing. Yet, there have not been direct, intracranial observations of the latency with which regions outside the temporal lobe respond to speech, or how these responses are impacted by task demands. We leveraged human intracranial recordings via stereo-EEG to measure responses from diverse forebrain sites during (i) passive listening to /bi/ and /pi/ syllables, and (ii) active listening requiring /bi/-versus-/pi/ categorization...

BACKGROUND: In children, hearing loss has been associated with hyperactivity, disturbed social interaction, and risk of cognitive disturbances. Mechanistic explanations of these relations sometimes involve language. To investigate the effect of hearing loss on behavioral deficits in the absence of language, we tested the impact of hearing loss in juvenile rats on motor, social, and cognitive behavior and on physiology of prefrontal cortex. METHODS: Hearing loss was induced in juvenile (postnatal day 14) male Sprague-Dawley rats by intracochlear injection of neomycin under general anesthesia...

The mismatch negativity and the P3a of the event-related EEG potential reflect the electrocortical response to a deviant stimulus in a series of stimuli. Although both components have been investigated in various paradigms, these paradigms usually incorporate many repetitions of the same deviant, thus leaving open whether both components vary as a function of the deviant's position in a series of deviant stimuli-i.e. whether they are subject to qualitative/quantitative habituation from one instantiation of a deviant to the next...

Hearing is critical to spoken language, cognitive, and social development. Little is known about how early auditory experiences impact the brain structure of children with bilateral sensorineural hearing loss. This study examined the influence of hearing aid use and residual hearing on the auditory cortex of children with severe to profound congenital sensorineural hearing loss. We evaluated cortical preservation in 103 young pediatric cochlear implant candidates (55 females and 48 males) by comparing their multivoxel pattern similarity of auditory cortical structure with that of 78 age-matched children with typical hearing...

Sensory stimulation is often accompanied by fluctuations at high frequencies (>30Hz) in brain signals. These could be "narrowband" oscillations in the gamma band (30-70 Hz) or non-oscillatory "broadband" high-gamma (70-150 Hz) activity. Narrowband gamma oscillations, which are induced by presenting some visual stimuli such as gratings and have been shown to weaken with healthy aging and the onset of Alzheimer's Disease, hold promise as potential biomarkers. However, since delivering visual stimuli is cumbersome as it requires head stabilization for eye tracking, an equivalent auditory paradigm could be useful...

Synaptic loss is a primary pathology in Alzheimer's disease and correlates best with cognitive impairment as found in post-mortem studies. Previously, we observed in vivo reductions of synaptic density with [11 C]UCB-J PET (radiotracer for synaptic vesicle protein 2A) throughout the neocortex and medial temporal brain regions in early Alzheimer's disease. In this study, we applied independent component analysis to synaptic vesicle protein 2A-PET data to identify brain networks associated with cognitive deficits in Alzheimer's disease in a blinded data-driven manner...

Spatiotemporally congruent sensory stimuli are fused into a unified percept. The auditory cortex (AC) sends projections to the primary visual cortex (V1), which could provide signals for binding spatially corresponding audio-visual stimuli. However, whether AC inputs in V1 encode sound location remains unknown. Using two-photon axonal calcium imaging and a speaker array, we measured the auditory spatial information transmitted from AC to layer 1 of V1. AC conveys information about the location of ipsilateral and contralateral sound sources to V1...