Functional specialisation of multisensory temporal integration in the mouse superior colliculus

TL;DR

The study shows how different parts of the mouse brain's superior colliculus handle timing of sensory signals, improving perception of the environment.

Contribution

The study reveals nonlinear integration and regional specialization in the superior colliculus for multisensory timing.

Findings

Multisensory neurons in the SC encode audiovisual delays through nonlinear integration.

Posterior-medial SC populations show superior temporal discriminability for peripheral sensory fields.

Multisensory neurons receive half of their local input from other multisensory neurons.

Abstract

Our perception of the world depends on the brain’s capacity to integrate information from multiple senses, with timing differences serving as crucial cues for binding or segregating cross-modal signals. The superior colliculus (SC) is a central hub for such integration, yet the contributions of its distinct regions remain poorly understood. Here we show, from recordings of over 5000 neurons in awake mice, that multisensory neurons reliably encode audiovisual delays through nonlinear integration of auditory and visual inputs. This nonlinearity enhances the precision of delay representation, with posterior-medial SC populations representing the peripheral sensory field showing superior temporal discriminability. Connectivity analyses reveal stronger coupling in the medial SC and function-specific recurrent networks, with multisensory neurons receiving about half of their local input from other multisensory neurons. Together, these results demonstrate how nonlinear integration, regional specialisation, and network architecture combine to support robust sensory binding and accurate encoding of temporal multisensory information.

Whether and how anatomically distinct regions of the superior colliculus (SC) exhibit specialisation in multisensory temporal integration to facilitate different behavioural responses are not fully understood. This study shows that nonlinear integration in the SC enhances temporal encoding of multisensory signals, varies across the sensory field, and is supported by specialized intracollicular subnetworks.

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