Fig. 2.

Relationship of baseline activity to performance. (A) Relationship in a single cell for target in the receptive field. (Top) Raster diagrams. Each dot is an action potential; successive lines are successive trials synchronized on the appearance of the array (vertical line). Trials separated according to incorrect fixation trials (blue) and correct fixation trials (red). Asterisks show 100-ms epochs where there was a significant difference (Mann–Whitney u test, multiple comparison compensation by false discovery rate, P < 0.05) between correct and incorrect trials. Graphs at bottom show poststimulus histograms (bin width 20 ms), activity (ordinate, spikes per s) plotted against time (abscissa) of the rasters above, colors as in the rasters. (B) Same as A, for distractor in the receptive field. (C) Relationship across the population. Each dot is the median value for a single cell. Red, monkey T; black, monkey R; closed circles, unsuccessful trials statistically different (Mann–Whitney u test, P < 0.05); open circles, successful vs. unsuccessful trials not statistically different.