Figure 1.

Task, Behavior, and Recording Locations

(A) Task. Following fixation on a central red dot (held until response interval; see below), each trial began with a cue stimulus indicating the current target. For each animal, two alternative cues were associated with two alternative targets based on preexperimental training (illustrated by stimuli for one animal in inset). After a first delay, the animal saw a choice display consisting of a single object to left or right of fixation or two objects, one to each side. Possible display objects included the cued target (T), the object associated with the alternative cue (inconsistent nontarget, NI), and a third object never serving as a target (consistent nontarget, NC). After a second delay, a change of fixation point to green cued the animal to indicate his behavioral decision. At this point, for go trials (T present in choice display), the monkey was rewarded with a drop of liquid for a saccade to the T location. For no-go trials (T absent), reward was contingent on holding fixation until the response interval finished (see Experimental Procedures).

(B) Mean response accuracies for each type of choice display.

(C) Approximate recording locations. ps, principal sulcus; sar, superior arcuate sulcus; iar, inferior arcuate sulcus. For further details, see Figure S1.