Diverse and dynamic influences of saccades on visual representations in the mouse superior colliculus

How do sensory systems account for stimuli generated by natural behavior? We addressed this question by examining how an ethologically relevant class of saccades modulates visual representations in the mouse superior colliculus (SC), a key region for sensorimotor integration. Leveraging the conserved natural tendency to make saccades that reset the eye-head angle to a default position via the optokinetic reflex, we developed an efficient and unbiased "white noise" approach to study the modulation of representations of visual stimuli by stochastically timed resetting saccades in large neuronal populations in awake, untrained head-fixed mice. Extracellular Neuropixels recordings revealed that saccades significantly impacted population representations of the visual probes in the SC, with early enhancement that began prior to saccade initiation and pronounced suppression for several hundred milliseconds following saccades, independent of units' visual response properties or directional tuning. To determine whether visual or motor signals are responsible for saccadic modulation, we presented fictive saccades-rapid translations of the visual scene-that simulated the visual experience during saccades in the absence of motor output. Some units exhibited similar modulation by fictive and real saccades, suggesting a sensory-driven origin of saccadic modulation, while others had dissimilar modulation, indicating a motor contribution. These findings establish a simple and robust mouse model to study how movements affect sensory representations and advance our understanding of the neural basis of natural visual coding across species and behaviors.