Separate signals for target selection and movement specification in the superior colliculus

At any given instant, multiple potential targets for saccades are present i n the: visual world, implying that a "selection process" within the brain d etermines: the target of the next eye movement, Some superior colliculus (S C) neurons: begin discharging seconds before saccade initiation, suggesting involvement in target selection or, alternatively, in postselectional sacc ade preparation. SC neurons were recorded in monkeys who selected saccade t argets on the basis of motion direction in a visual display. Some neurons c arried a direction- selective visual signal, consistent with a role in targ et selection in this task, whereas other SC neurons appeared to be more inv olved in postselection specification of saccade parameters.