Fig. 2.

Mutual information analyses as a function of time. (Top) Eighty neurons from the medial premotor cortex. Each row corresponds to a different neuron. (All neurons in the dataset are included for which there were five or more trials for each condition.) The times when the f₂ stimuli are applied (the delay period and the behavioral response period) are indicated (Fig. 1). In particular, the f₂ period is 3.5–4.0 s. The postponed response delay period is 4.0–7.0 s. The behavioral response can be started at signal given at 7.0 s. The mutual information shown is that between the firing rate in a 200-ms window (sliding every 100 ms) and the response made by the monkey. The calibration bar shows the information value for a single neuron. (Middle) Eighty neurons in pool 1 of the graded firing rate simulation. Each row is a single neuron. The rows are sorted by the amount of information during the decision period, 3.5–4.0 s, which corresponds to the f₂ period for the MPC neurons. The delay period is 4–7 s. The equal external inputs are applied at t = 7.0–7.5 s, labeled recall period. The mutual information shown is that between the firing rate in a 200-ms sliding window and the firing in the decision period. (Bottom) SF simulation (conventions as in Middle).