MIDBRAIN CIRCUITS FOR THE PURSUIT OF MOVING TARGETS IN MICE

Extraction of relevant stimulus features from the sensory scene must be dynamically coupled to the execution of appropriate adaptive responses to ensure survival. Coordination between sensory processing and motor output is critical during goal-directed behaviours, where animals continuously integrate sensory information and adjust their actions in real time. To investigate these processes, we developed a freely moving behavioural paradigm in which closed-loop presentation of visual stimuli on a touchscreen guided highly reproducible pursuit behaviour in mice. Target velocity and contrast determined the success of the interceptive approach. We found that mice flexibly adapted their pursuit strategies to the demands of the task by adjusting their trajectories and running speed. Importantly, they were able to capture targets that changed velocity mid-trial or were transiently masked, indicating that they use a combination of spatiotemporal prediction and continuous online sensorimotor updates.
To understand the neural basis of pursuit behaviour, we investigated the role of the superior colliculus (SC), a midbrain structure involved in visual sensorimotor transformations. Optogenetic silencing of the SC impaired orienting towards the target during pursuit. Building on this evidence, we performed Neuropixels recordings in freely moving mice. Neural activity was correlated with trial onset, and neurons were tuned to the presence of the target. Trial type could be decoded from SC population activity earlier than from behaviour, suggesting that SC activity encodes task-relevant sensory information prior to motor execution. Moreover, SC responses adapted to changes in sensory evidence, providing insight into how this structure dynamically supports goal-directed orienting behaviour.