Sound-evoked orofacial motion only affects a fraction of visually responsive V1 neurons in a multisensory detection task with delayed reward delivery

Abstract

Auditory stimuli have been known to elicit neural responses in visual cortical areas, but such responses are partly associated with sound-evoked orofacial movements. However, it remains unclear to what extent neural correlates of movement can be dissociated from non-motor correlates. Here we developed a paradigm with a forced delayed-response mechanism by means of a moving reward apparatus in order to test whether this results in low amounts of movement-related neural activity shortly after stimulus onset. Animals performed a multisensory detection task, while we recorded neural activity from V1 and measured orofacial motion. During the delay, when only the stimulus was present, orofacial motion was relatively low. Reward-related motion increased after the delay, with a concomitant increase in motor-related spiking activity. Visual stimulation did neither elicit considerable motion nor corresponding neural responses in the delay period. Conversely, salient auditory stimuli led to modest, but increased orofacial motion and related neuronal activity during the delay. We identified a subpopulation of visually responsive V1 neurons that did not show correlations with orofacial movement, with only the stimulus being represented. These results present a forced delayed-response window as a method to help disentangle motor-related activity from visual (but not auditory) processing and show that motor-related activity only affects a fraction of visually selective neurons.