Auditory streaming emerges from fast excitation and slow delayed inhibition

TL;DR

This paper presents a neural circuit model with fast excitation and slow inhibition that explains how the brain perceives auditory streaming as either integrated or segregated sounds, aligning with experimental observations.

Contribution

It introduces a minimal firing rate model with specific neural interactions that reproduces key perceptual phenomena in auditory streaming.

Findings

Model reproduces perceptual states of integration and segregation.

Slow inhibition causes forward masking during segregation.

Fast excitation facilitates integration across large pitch differences.

Abstract

In the auditory streaming paradigm alternating sequences of pure tones can be perceived as a single galloping rhythm (integration) or as two sequences with separated low and high tones (segregation). Although studied for decades, the neural mechanisms underlining this perceptual grouping of sound remains a mystery. With the aim of identifying a plausible minimal neural circuit that captures this phenomenon, we propose a firing rate model with two periodically forced neural populations coupled by fast direct excitation and slow delayed inhibition. By analyzing the model in a non-smooth, slow-fast regime we analytically prove the existence of a rich repertoire of dynamical states and of their parameter dependent transitions. We impose plausible parameter restrictions and link all states with perceptual interpretations. Regions of stimulus parameters occupied by states linked with each percept matches those found in behavioral experiments. Our model suggests that slow inhibition masks the perception of subsequent tones during segregation (forward masking), while fast excitation enables integration for large pitch differences between the two tones.