Speech intelligibility declines with age and sensorineural hearing damage (SNHL). However, it remains unclear whether cochlear synaptopathy (CS), a recently discovered form of SNHL, significantly contributes to this issue. CS refers damaged auditory-nerve synapses that innervate the inner hair cells there is currently no go-to diagnostic test available. Furthermore, age-related can comprise various aspects (e.g., cell damage, CS) each play role in impaired sound perception. To explore link...

People with cochlear hearing loss have substantial difficulty understanding speech in real-world listening environments (e.g., restaurants), even amplification from a modern digital aid. Unfortunately, disconnect remains between human perceptual studies implicating diminished sensitivity to fast acoustic temporal fine structure (TFS) and animal showing minimal changes neural coding of TFS or slower envelope (ENV) structure. Here, we used general system-identification (Wiener kernel) analyses...

While changes in cochlear frequency tuning are thought to play an important role the perceptual difficulties of people with sensorineural hearing loss (SNHL), possible temporal processing deficits remains less clear. Our knowledge envelope coding impaired cochlea is limited two studies that examined auditory-nerve fiber responses narrowband amplitude modulated stimuli. In present study, we used Wiener-kernel analyses broadband Gaussian noise anesthetized chinchillas quantify noise-induced...

We hypothesized that active outer hair cells drive cochlear fluid circulation. The hypothesis was tested by delivering the neurotoxin, kainic acid, to intact round window of young gerbil cochleae while monitoring auditory responses in nucleus. Sounds presented at a modest level significantly expedited acid delivery. When outer-hair-cell motility suppressed salicylate, facilitation effect compromised. A low-frequency tone more effective than broadband noise, especially for drug delivery...

Frequency analysis by the cochlea forms a key foundation for all subsequent auditory processing. Stimulus-frequency otoacoustic emissions (SFOAEs) are potentially powerful alternative to traditional behavioral experiments estimating cochlear tuning without invasive testing, as is necessary in humans. Which methods accurately predict remains controversial due only single animal study comparing SFOAE-based, behavioral, and frequency same species. The budgerigar ( Melopsittacus undulatus )...

Speech intelligibility can vary dramatically between individuals with similar clinically defined severity of hearing loss based on the audiogram. These perceptual differences, despite equal audiometric-threshold elevation, are often assumed to reflect central-processing variations. Here, we compared peripheral-processing in auditory nerve (AN) fibers male chinchillas two prevalent etiologies: metabolic (MHL) and noise-induced (NIHL). MHL results from age-related reduction endocochlear...

Amplitude modulation (AM) is a crucial feature of many communication signals, including speech. Whereas average discharge rates in the auditory midbrain correlate with behavioral AM sensitivity rabbits, neural bases species human-like acuity are unexplored. Here, we used parallel and neurophysiological experiments to explore (midbrain) perception an avian speech mimic, budgerigar (Melopsittacus undulatus). Behavioral was quantified using operant conditioning procedures. Neural studied...

Loss of auditory-nerve (AN) afferent cochlear innervation is a prevalent human condition that does not affect audiometric thresholds and therefore remains largely undetectable with standard clinical tests. AN loss widely expected to cause hearing difficulties in noise, known as "hidden loss," but support for this hypothesis controversial. Here, we used operant conditioning procedures examine the perceptual impact on behavioral tone-in-noise (TIN) sensitivity budgerigar (Melopsittacus...

SUMMARY Songbirds exhibit seasonal plasticity in a broad variety of behavioral and morphological traits associated with reproduction. Changes song production are well described while changes reception not. In the present study, we test for variation auditory processing house sparrow (Passer domesticus L.) using brainstem responses (ABRs) to tone bursts. We measured amplitude latency first ABR peak spring, summer autumn at stimulus frequencies from 0.8 6.4 kHz intensity levels 24 80 dB SPL....

Summary 1. Environmental constraints in woodland habitats favour long‐range communication signals with slow modulations of frequency and amplitude, while open faster modulations. 2. Spectral filtering by the peripheral auditory system results a trade‐off between resolution temporal Greater requires integration acoustic over longer period time, which turn decreases responsiveness to 3. Here, we test hypothesis songbirds that have selected for narrowly tuned filters high tonal elements,...

Hearing in noise is a problem often assumed to depend on encoding of energy level by channels tuned target frequencies, but few studies have tested this hypothesis. The present study examined neural correlates behavioral tone-in-noise (TIN) detection budgerigars (<i>Melopsittacus undulatus</i>, either sex), parakeet species with human-like sensitivity many simple and complex sounds. Behavioral tones band-limited was assessed using operant-conditioning procedures. Neural recordings were made...