Reduction in sound discrimination in noise is related to envelope similarity and not to a decrease in envelope tracking abilities

Abstract

In quiet, envelope tracking in the low amplitude modulation range (<20 Hz) is correlated with the neuronal discrimination between communication sounds as quantified by mutual information from the cochlear nucleus up to the auditory cortex.* At each level of the auditory system, auditory neurons keep their abilities to track the communication sound envelopes in situations of acoustic degradation such as vocoding and the addition of masking noises up to a signal-to-noise ratio of -10 dB. * In noise, the increase in between-stimulus envelope similarity explains both the reduction in behavioral and neuronal discrimination in the auditory system. * Envelope tracking can be viewed as a universal mechanism allowing neural and behavioral discrimination as long as the temporal envelope of communication sounds display some differences.

Can Extensive Training Transform a Mouse into a Guinea Pig? An Evaluation Based on the Discriminative Abilities of Inferior Colliculus Neurons

“…Mice were trained to an auditory discrimination task with a training procedure similar to those described in previous studies [9,[11][12][13]. First, each mouse was habituated to being restrained by progressively increasing the time during which the mouse was head-fixed with the hook screwed to a small metallic post (from 10 min to 40 min over a week) in a red plastic tube and rested on aluminum foil.…”

“…Positive and negative stimuli were played in a pseudorandom order with the constraint that 3 positive and 3 negative sounds must be played every 6 trials. The S+ and S− were guinea pig whistles used in several previous electrophysiological studies to assess the neuronal discrimination performance (indexed by mutual information) in the auditory system, from cochlear nucleus to auditory cortex [8,9,14]. The two whistles mostly differ in their temporal envelopes but also have slightly different spectral content (see Figure 1A in [8,9]).…”

“…However, recent studies have challenged this view by comparing the discriminative abilities of auditory neurons at five levels of the auditory system: by quantifying the neuronal discrimination between acoustically similar stimuli (four guinea pig whistles) and using Mutual Information (MI) as a metric, it was reported that thalamic and brainstem neurons largely outperformed cortical neurons [8,9]. More precisely, both the individual (from individual recordings, MI ind ) and the populational discriminative abilities (from small populations of recordings, MI pop ) were higher in the auditory thalamus, inferior colliculus and cochlear nucleus than in the auditory cortex, both in silence and noisy conditions.…”

“…Surprisingly, in the more challenging conditions, i.e., in a −10 dB signalto-noise ratio (SNR), inferior colliculus (IC) neurons showed the highest discrimination abilities, suggesting that the neurons of this brainstem structure are potentially responsible for robust representations of target stimuli in noisy conditions. One potential explanation is that the envelope tracking abilities of neurons are higher in the brainstem than in the cortex, and these abilities are preserved in noisy conditions [9].…”

Quantum information processing with superconducting circuits: a perspective

“…Then the high-frequency background noise in the cabin from the air conditioning and engines may swamp the music signal. And finally, the sensitivity and frequency response of passenger's ears, and the processing in the brain [143][144][145], may be less than perfect, making it difficult to discriminate against the noise. For the traveller, high-quality headphones with noise suppression therefore make a big difference.…”