Selectivity for task rules in the SEF neurons. A, Activity of an example SEF neuron conditioned on task rule during the percstim epoch. The neuron fired more when the size rule RS was in effect, with the difference in firing emerging ∼300 ms after decision target onset. Conventions are as in Figure 4. B, Pie chart showing the numbers of rule selective neurons and their preference (rule RS, rule RB, or NS, nonselective). Histogram shows magnitudes of the neurons' significant (black) or nonsignificant (white) rule selectivity biases.