Abstract
In everyday life, we integrate visual and auditory information in routine tasks such as navigation and communication. Whereas concurrent sound can improve visual perception, the neuronal correlates of this audiovisual integration are not fully understood. Specifically, it remains unknown whether sound-induced improvement in detection and discriminability of visual stimuli is reflected in neuronal firing patterns in the primary visual cortex (V1). Furthermore, presentation of sound can induce movement in the subject, but little is understood about whether and how sound-induced movement affects audiovisual integration in V1. We investigated how sound and movement interact to modulate V1 visual responses in awake, head-fixed mice and whether this interaction improves neuronal encoding of the visual stimulus. We presented visual drifting gratings with and without simultaneous auditory white noise to awake male and female mice while recording mouse movement and V1 neuronal activity. Sound modulated light-evoked activity of 80% of light-responsive neurons, with 95% of neurons increasing activity when the auditory stimulus was present. Sound consistently induced movement. However, a generalized linear model revealed that sound and movement had distinct and complementary effects of the neuronal visual responses. Furthermore, decoding of the visual stimulus from the neuronal activity was improved with sound, even when controlling for movement. Thus, sound and movement modulate visual responses in complementary ways, improving neuronal representation of the visual stimulus. This study clarifies the role of movement as a potential confound in neuronal audiovisual responses and expands our knowledge of how multimodal processing is mediated in the awake brain.
Significance statement Sound and movement are both known to modulate visual responses in the primary visual cortex, however sound-induced movement has largely remained unaccounted for as a potential confound in audiovisual studies in awake animals. Here, authors found that sound and movement both modulate visual responses in an important visual brain area, the primary visual cortex, in distinct, yet complementary ways. Furthermore, sound improved encoding of the visual stimulus even when accounting for movement. This study reconciles contrasting theories on the mechanism underlying audiovisual integration and asserts the primary visual cortex as a key brain region participating in tripartite sensory interactions.
Preprint published on BioRXiv https://doi.org/10.1101/2021.08.03.454738
Competing Interest Statement
The authors have declared no competing interest.