Figure 6. Neural activity related to direction identification in a veridical judgment task.

(A) Neural response to the motion stimulus alone. (Left) Spatiotemporal firing pattern of pyramidal cells superimposed by the time course of the population vector (magenta). The arrow indicates the coherent motion direction (200°) of the stimulus. The motion stimulus is presented at 500 ms and lasts 1 s. (Right) Network activity profile at stimulus offset. The firing rate is calculated by counting the number of spikes fired by each neuron within 50 ms preceding the stimulus offset, divided by 50 ms. (B) Neural response to the microstimulation of MT neurons alone. The black arrow marks the microstimulated direction (90°). Same conventions as in (A). (C) Neural response to the simultaneous presentation of the motion stimulus and microstimulation. (Top three panels) Neural activity on three sample trials. (Bottom panels) Time course of population firing rates of two neural pools separately centered at 90° (red) and 200° (black), corresponding to the above three individual trials (from left to right).