Population statistics of FF in each task. Top, Histograms of FF during the foreperiod, under the preferred stimulus during delay, and under the least preferred stimulus during delay, for all neurons with well-tuned delay activity. Bottom, Scatterplot of FF under the preferred stimulus versus under the least preferred stimulus, along with histogram of the difference in FF (preferred – the least preferred stimulus). A, Results of the ODR task. FF under the preferred stimulus was slightly greater than that under the least preferred stimulus. B, Results of the VDD task. FF under the preferred stimulus was not significantly different from that under the least preferred stimulus. C, Results of the MNM task. FF under the preferred stimulus was greater than that under the least preferred stimulus. *p < 0.05. **p < 0.01. ***p < 0.001.