The establishment of a meaningful alignment between sensory and motor maps is a prerequisite for the execution of all animal behaviours. A prime candidate brain region for implementing this sensory-motor transformation is the superior colliculus (SC). However, the extent to which motor and sensory representations converge in individual collicular motor neurons and what is the logic governing the presumed sensory-motor alignment remains unknown.
In order to understand the nature and logic of sensory-motor integration, in vivo intracellular and extracellular recordings were performed across the SC, in restrained and unrestrained conditions, to assess both the motor and the sensory tuning of individual neurons. Whilst traditional models of sensory-motor alignment have centred on the mapping between static spatial features, such as stimulus location and movement endpoints, we show that collicular motor units respond primarily to kinetic visual features, and reveal the existence of an alignment in vectorial space between the encoded sensory flow and movement vectors rather than between visual receptive fields and movement endpoints as previously hypothesised. Such an alignment is ideally placed to drive rapid interception of incoming targets, we show that a neural network built on these connectivity premises is able to support key aspect of SC functionality, such as visual grasping and tracking.
Overall these findings reveal a novel dimension of the sensory motor alignment. By extending the concept of spatial-motor alignment from the static to the kinetic domain this work provides a novel conceptual framework to understand the origin of sensory-motor convergence and its relevance in guiding sensory-driven goal-directed behaviour.