Neuronal activity in macaque supplementary eye field during planning of saccades in response to pattern and spatial cues

The aim of this study was to determine whether neuronal activity in the mac aque supplementary eye field (SEF) is influenced by the rule used for sacca dic target selection. Two monkeys were trained to perform a variant of the memory-guided saccade task in which any of four visible dots (rightward, up ward, leftward, and downward) could be the target. On each trial, the cue i dentifying the target was either a spot flashed in superimposition on the t arget (spatial condition) or a foveally presented digitized image associate d with the target (pattern condition). Trials conforming to the two conditi ons were interleaved randomly. On recording from 439 SEF neurons, we found that two aspects of neuronal activity were influenced by the nature of the cue. 1) Activity reflecting the direction of the impending response develop ed more rapidly following spatial than following pattern cues. 2) Activity throughout the delay period tended to be higher following pattern than foll owing spatial cues. We consider these findings in relation to the possible involvement of the SEF in processes underlying attention, arousal, response -selection, and motor preparation.