Situating the superior colliculus within the gaze control network

A wealth of evidence, much of it reviewed in this book, suggests that the superior colliculus (SC) plays a crucial role in the control of orienting eye and head movements. Activity in the superior colliculus, for example, predicts both the metrics and the timing of orienting movements. Electrical microstimulation of the SC, to take another example, can be used to elicit saccadic eye movements that are virtually indistinguishable from naturally occurring saccades. Based upon data like these, many neurobiologists have come to regard the SC as a command center from which nearly all saccades are generated. Thus, the SC has come to be viewed as a final common path for the generation of rapid eye movements in the same sense that Sherrington used the term final common path to describe alpha-motor neurons in the spinal cord. For most oculomotor scientists, activity in the SC is assumed to reflect the cumulative output of the neural systems that select and execute orienting movements.