Figure 8.

Speed tuning. A, A black spot (360 μm diameter) was repeatedly moved into and out of a cell's receptive field at six different speeds on a gray background. The binned spike rate (spikes per second) of the ON response (left, spot leaving the receptive field) and the OFF response (right, spot entering the receptive field) was averaged across seven stimulus cycles per spot speed. The height of each box indicates a spike rate of 200 Hz. B, Spike count per ON and OFF burst elicited by moving black spots, averaged across six stimulus cycles per spot speed in six cells. C, Peak spike rates at different spot speeds, averaged across six stimulus cycles per spot speed in six cells. Data points in B and C were fitted with a second-order bandpass function (solid curves). Gray, ON response; black, OFF response.