A sparse code for natural sound context in auditory cortex

• Published in: Current research in neurobiology Vol. 6; p. 100118
• Main Authors: López Espejo, Mateo, David, Stephen V.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2024; Elsevier
• Subjects: from the special issue: How Expectation Transforms Neural Representations and Perception, edited by Kerry Walker and Christopher I. Petkov
• ISSN: 2665-945X; 2665-945X
• DOI: 10.1016/j.crneur.2023.100118

Accurate sound perception can require integrating information over hundreds of milliseconds or even seconds. Spectro-temporal models of sound coding by single neurons in auditory cortex indicate that the majority of sound-evoked activity can be attributed to stimuli with a few tens of milliseconds. It remains uncertain how the auditory system integrates information about sensory context on a longer timescale. Here we characterized long-lasting contextual effects in auditory cortex (AC) using a diverse set of natural sound stimuli. We measured context effects as the difference in a neuron's response to a single probe sound following two different context sounds. Many AC neurons showed context effects lasting longer than the temporal window of a traditional spectro-temporal receptive field. The duration and magnitude of context effects varied substantially across neurons and stimuli. This diversity of context effects formed a sparse code across the neural population that encoded a wider range of contexts than any constituent neuron. Encoding model analysis indicates that context effects can be explained by activity in the local neural population, suggesting that recurrent local circuits support a long-lasting representation of sensory context in auditory cortex. [Display omitted] •Recent sound history defines a sensory context that modulates the cortical representation of ongoing natural sounds.•The similarity between past and ongoing sounds defines the amplitude of context modulation.•Context effects are distributed across the neural population, forming a sparse code.•Inhibitory interneurons show context effects that were smaller but more densely distributed across stimuli.•Context effects are explained by adaptation and recent neural population activity.