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bioRxiv
BIORXIV
bioRxiv
Cold Spring Harbor Laboratory

10.1101/2024.05.24.595822
preprint
1
Article
A hierarchy of processing complexity and timescales for natural sounds in human auditory cortex
Rupp Kyle M.
Hect Jasmine L.
Harford Emily E.
Holt Lori L. http://orcid.org/0000-0002-8732-4977

Ghuman Avniel Singh
Abel Taylor J.
26 5 2024
2024.05.24.595822http://biorxiv.org/lookup/doi/10.1101/2024.05.24.595822
nihpp-2024.05.24.595822.pdf
Abstract

Efficient behavior is supported by humans’ ability to rapidly recognize acoustically distinct sounds as members of a common category. Within auditory cortex, there are critical unanswered questions regarding the organization and dynamics of sound categorization. Here, we performed intracerebral recordings in the context of epilepsy surgery as 20 patient-participants listened to natural sounds. We built encoding models to predict neural responses using features of these sounds extracted from different layers within a sound-categorization deep neural network (DNN). This approach yielded highly accurate models of neural responses throughout auditory cortex. The complexity of a cortical site’s representation (measured by the depth of the DNN layer that produced the best model) was closely related to its anatomical location, with shallow, middle, and deep layers of the DNN associated with core (primary auditory cortex), lateral belt, and parabelt regions, respectively. Smoothly varying gradients of representational complexity also existed within these regions, with complexity increasing along a posteromedial-to-anterolateral direction in core and lateral belt, and along posterior-to-anterior and dorsal-to-ventral dimensions in parabelt. When we estimated the time window over which each recording site integrates information, we found shorter integration windows in core relative to lateral belt and parabelt. Lastly, we found a relationship between the length of the integration window and the complexity of information processing within core (but not lateral belt or parabelt). These findings suggest hierarchies of timescales and processing complexity, and their interrelationship, represent a functional organizational principle of the auditory stream that underlies our perception of complex, abstract auditory information.
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pmc
