Fig. 1.

Schematic representation of the behavioral task. (A) Sequence of events in the free-viewing visual search task. Monkeys were required to fixate the central fixation spot and subsequently the cue that indicated the target stimulus. Following a delay period, monkeys were allowed to scan the array to locate and fixate the target. The solid lines indicate a hypothetical eye position trace (saccades to different stimuli in the array). (B) Conditions used to study feature attention. The oval indicates a hypothetical neuronal RF during the initial fixation. Note that stimuli in the RF are the same in all displays. However, depending on the identity of the target (shown below each display), the task relevance of the RF stimuli is different in the different trials.