side of the anterior commissure. The coordinates of the FEF recording sites for monkey 1 were 1 mm anterior, 8–12 mm dorsal, and 13–16 mm to the right side of the anterior commissure. The coordinates of the FEF recording sites for monkey 2 were 2–4 mm anterior, 10–16 mm dorsal, and 12–16 mm to the right side of the anterior commissure. The ACC recording sites included areas 24d, 24b, and 10m according to the composite monkey brain atlas of Van Essen et al.57. The proper location of the FEF electrodes was confirmed by electrical microstimulation as described previously2 (train duration of 70 ms set at 300 Hz, biphasic pulses of 0.2 ms duration, current <50 μA). Supplementary Figure 1 shows a reconstruction of the ACC and FEF recording sites.
