Neural Control of Instantaneous Kinematics of Eye-Head Gaze Shifts in Monkey Superior Colliculus

Abstract

The midbrain superior colliculus (SC) is a crucial sensorimotor stage for programming and execution of saccadic eye-head gaze shifts. Although it is well established that cells in the SC encode a neural command that specifies the coordinates of the upcoming gaze-shift vector, there is controversy about the role of the firing rate dynamics of SC neurons in generating saccades. In our earlier work, we proposed a simple quantitative model that explains how the recruited SC population specifies the detailed kinematics (trajectories and velocity profiles) of head-restrained saccadic eye movements. We here show that the same principles may apply to a wide range of saccadic eye-head gaze shifts with strongly varying kinematics. This is quite surprising, given the substantial nonlinearities and redundancy in programming and execute goal-directed eye-head gaze shifts to peripheral targets. We hypothesize that our findings provide additional evidence for an important role of the SC in the optimal control of saccades.