Biology subjects

Huetz, C.

Publications and source records attributed to Huetz, C..

3 recordsLinked to original sources

bioRxiv2022

Subcortical and cortical tracking of communication sound envelopes in challenging listening conditions

Humans and animals constantly face challenging acoustic environments such as various background noises restricting the detection, discrimination and identification of behaviorally salient sounds. Here, we disentangled the role of temporal envelope tracking on the decrease in neuronal and behavioral discrimination between communication sounds in situations of acoustic degradations. We simulated responses of auditory nerve fibers and recorded neuronal activity in cochlear nucleus, inferior colliculus, thalamus and auditory cortex in anesthetized guinea-pigs. Furthermore, a Go/No-Go sound discrimination task involving two of the guinea-pig whistles was performed on mice in silence and noise. For all conditions, we found that auditory neurons better track the slow amplitude modulations (<20 Hz) of the stimulus envelopes than the faster ones. In addition, the decrease in neuronal and behavioral discrimination performance in noise can be explained by an increased similarity of the vocalization envelopes in the low frequency range (<20 Hz). Together, these results suggest that slow envelope tracking is a general property of auditory neurons, and any difference between the slow envelopes of natural stimuli allows coping with degraded conditions.

neuroscience↗

bioRxiv2020

A distributed network of noise-resistant neuronsin the central auditory system

Background noise strongly penalizes auditory perception of speech in humans or vocalizations in animals. Despite this, auditory neurons successfully detect and discriminate behaviorally salient sounds even when the signal-to-noise ratio is quite poor. Here, we collected neuronal recordings in cochlear nucleus, inferior colliculus, auditory thalamus, primary and secondary auditory cortex in response to vocalizations presented either against a stationary or a chorus noise. Using a clustering approach, we provide evidence that five behaviors exist at each level of the auditory system from neurons with high fidelity representations of the target, named target-specific neurons, mostly found in inferior colliculus and thalamus, to neurons with high fidelity representations of the noise, named masker-specific neurons mostly found in cochlear nucleus in stationary noise but in similar proportions in each structure in chorus noise. This indicates that the neural bases of auditory perception in noise rely on a distributed network along the auditory system.

neuroscience↗

bioRxiv2019

Cortical and subcortical neurons discriminate sounds in noise on the sole basis of acoustic amplitude modulations

Humans and animals maintain accurate sound discrimination in the presence of loud sources of background noise. It is commonly assumed that this ability relies on the robustness of auditory cortex responses. However, no attempt has been made to characterize neural discrimination of sounds masked by noise at each stage of the auditory system and disentangle the sub-effects of noise, namely the distortion of temporal cues conveyed by modulations in instantaneous amplitude and frequency, and the introduction of randomness (stochastic fluctuations in amplitude). Here, we measured neural discrimination between communication sounds masked by steady noise in the cochlear nucleus, inferior colliculus, auditory thalamus, primary and secondary auditory cortex at several signal-to-noise ratios. Sound discrimination by neuronal populations markedly decreased in each auditory structure, but collicular and thalamic populations showed better performance than cortical populations at each signal-to-noise ratio. Comparison with neural responses to tone-vocoded sounds revealed that the reduction in neural discrimination caused by noise was mainly driven by the attenuation of slow amplitude modulation cues, with the exception of the cochlear nucleus that showed a dramatic drop in discrimination caused by the randomness of noise. These results shed new light on the specific contributions of subcortical structures to robust sound encoding, and demonstrate that neural discrimination in the presence of background noise is mainly determined by the distortion of the slow temporal cues conveyed by communication sounds.

neuroscience↗