Inter- and Intra-hemispheric Sources of Vestibular Signals to V1

Sensations often trigger movements, but one’s movements also generate sensory experience. Vestibular organs monitor head movements and contribute to the brain’s ability to distinguish between self- and externally-generated sensory stimuli. Signals from the vestibular organs are broadcasted throughout the brain, including primary sensory regions such as the primary visual cortex (V1). However, what type of signals relative to head movements reach V1 and what the upstream sources of these signals are, remains poorly understood. Here we show that, in the absence of visual input, V1 neurons encode a complex representation of head movements in a cortical depth specific manner. Moreover, we discovered that the ipsilateral latero-posterior thalamus (LP) and the contralateral visual cortex are key sources of vestibular input to V1. The ipsilateral LP provides the main head movement signal and this signal is biased toward contraversive head movements (i.e. clockwise head movements when recording from left V1). Instead, the contralateral visual cortex provides head-movement signals during ipsiversive head movements. Thus, this study reveals a direction specific recruitment of intra- and inter-hemispheric sources of vestibular signals to V1.