Does the superior colliculus not encode the motor error? A new model of the saccadic system

Summary form only given, as follows. The superior colliculus (SC) is a motor center of the saccadic eye movement in the brain stem. A well-defined motor map of saccade to the contralateral visual field is formed in the SC. Electrical stimulation of the SC evokes a saccade with short latency. In some cases of colliding saccades where a stimulation-induced saccade interrupts a prior saccade, the vectorial displacement of a second saccade had quite different dimensions from what the motor map of the SC indicated. The author proposes a novel model of the saccadic system to explain this phenomenon and also the frequent occurrence of a compensatory saccade with an unusually short latency of 20 ms or less