Functional properties of neurons in the monkey superior colliculus: coupling of neuronal activity and saccade onset.

One class of superior colliculus neuron was isolated which meets two criteria for participation in the initiation of visually elicited saccades. First, the pulse of spike activity recorded from these neurons was tightly coupled to saccade onset, preceding the onset of eye movements by approximately 20 msec. Secondly, if a visual stimulus sometimes elicited a saccade and sometimes failed to elicit a saccade, the occurrence of the spike pulse was highly correlated with saccade occurrence. For these neurons, there was a clear distinction between the most vigorous neuronal activity occurring in the absence of a saccade and the least vigorous activity accompanying appropriate saccades. These findings are consistent with views which attribute to the superior colliculus a role in the initiation of visually elicited saccades.