Sample cell in FEF. (A) Activity of a single cell in FEF during the MIB task. Eleven individual trials are represented. The top trace of each trial represents the target; thick green line represents target ON, and thin black line target OFF. The middle trace represents lever presses; bars above the black trace represent a lever press signaling the appearance of the target, and bars below the black trace represent a lever press signaling the disappearance of the target. Green, black and red bars indicate real appearances, real disappearances and illusory transitions respectively. The lower trace (in blue) represents the spiking activity of the neuron; each tick corresponds to one action potential. (B) Average activity of cell shown in (A) preceding lever responses indicating target ON (top) and target OFF (bottom). Blue and Red traces indicate activity preceding real and illusory transitions respectively. Dark traces indicate activity exceeding two standard deviations from the mean. (C) Raster plot aligned to target ON (top) and OFF (bottom) at time 0 (blue vertical line), and sorted by reaction time, indicated by blue lines.