Fig. 3.

Dimming detection task. A: after 300 ms of fixation, 3 larger bars were presented among smaller distractor bars. One of the larger bars overlapped with a V4-RF. In half of the trials a train of 20 pulses (total duration 100 ms) with a current corresponding to 50% of the phosphene detection threshold was delivered to V4. After the end of the pulse train, 1 of the bars dimmed for 100 ms and monkeys had to make a saccade toward this bar. The luminance decrement was controlled by a staircase that kept performance at 79.4%. B: overlap between the RF of the stimulated V4 recording site and the bar in an example session. Color scale as in Fig. 1B. C: staircases of an example session, both for the blank (i.e., no MS) and the MS condition with a bar in the stimulated V4-RF. D: thresholds for blank and MS conditions of the example session computed as the mean of the last 15 reversals. Error bars indicate SE of the staircases.