Spiking was stronger and more informative for contralateral than ipsilateral objects. Average MUA was significantly higher for contralateral than ipsilateral samples throughout the trial (Figure 2A, stars; p < 0.01, corrected, permutation paired t test). In fact, for ipsilateral samples, MUA was above baseline on average only during the response to the sample presentation and a brief ‘‘ramp-up’’ at the end of the delay (Figure 2A, dots; p < 0.01, corrected, randomized sign test). Ipsilateral samples had only a weak effect on spiking during the delay. Unlike contralateral samples, which increased spiking, ipsilateral samples elicited a balance between increased and decreased spiking relative to baseline (Figure S1).
