Neural dynamics in superior colliculus of freely moving mice

Vision is an active process that depends on head and eye movements to explore the visual environment. Superior colliculus (SC) is known for its role in generating these movements, as well as processing visual information, but has not been studied extensively during free movement in complex visual environments. To determine the impact of active vision, we recorded neural activity across the depth of SC during free movement while simultaneously recording eye and head position. We find that superficial SC (sSC) neurons respond to visual input following gaze-shifting saccadic movements, whereas deep SC (dSC) neurons respond to the movements themselves, as demonstrated by their sustained response in darkness. Additionally, we find motor responses in dSC are more correlated to head movements rather than eye movements. Furthermore, we compared sSC gaze shift responses to known gaze shift responses in primary visual cortex (V1), finding similarities in key response types, although the temporal sequences following gaze shifts differ between the regions. Our results demonstrate distinct visual processing differences between SC and V1 as well as highlighting the various roles SC plays during active vision.