Figure 1.

Task and recording sites. A, Schematic of the saccade task. The animals were required to fixate centrally and after a variable fixation time the fixation spot was toggled off at the same time a target was presented either to the left or right. The animals then made a saccade toward the target and were required to hold the target for 500 ms to successfully complete a trial. Stochastic reward (p = 0.7) was delivered for correct trials. B, Location of the 8 microelectrode arrays on the prefrontal cortex, surrounding the principal sulcus. Each array had 96 electrodes in a 10 × 10 arrangement. Numbers on the gray squares are an example of categorical distance, from the array located ventrolateral to the caudal end of the principal sulcus of the left hemisphere (labeled 0). PS, principal sulcus; Arc, arcuate sulcus; CS, central sulcus.