Neural control of saccadic eye movements.

Recent experiments report that localization of brief targets presented during an ongoing saccade is not accurate. Because interpretations of these findings challenge an important tenet of existing oculomotor models, we examine the methodological and logical bases of these conclusions. Also, we review recent research related to the roles of the frontal eye fields and cerebellum in the control of saccadic eye movements. Pathways by which neurons in the frontal eye fields control the initiation and metrics of saccades have been clarified by studying the functional properties of neurons in the frontal eye fields that project to oculomotor regions of the pons, and the discovery of a short-latency pathway that enables relatively direct control of saccade initiation. We review the puzzling literature on the role of vermal lobules VIc, VII and the fastigial nuclei in the control of saccadic eye movements and suggest a testable hypothesis about how the fastigial projection to inhibitory burst neurons could modify saccade metrics.