Fig. 3.

Average left (1st row) and right (2nd row) hemisphere ERPs with the search target in the hemifield contralateral (dark curves) and ipsilateral (light curves) to the recording site. Bands around activity curves indicate SE. Solid vertical lines indicate onset of the m-N2pc. The bottom row shows histograms of m-N2pc minus single-neuron selection times for each monkey, in which m-N2pc was computed using contralateral vs. ipsilateral target responses. Despite the increased number of trials associated with the m-N2pc, single-neuron spikes selected targets earlier than the hemisphere-based m-N2pc (Wilcoxon signed-rank test, P < 0.001 for each monkey). Dashed vertical lines indicate zero difference between m-N2pc and neuron.