Figure 2.
Spatiotemporal tuning and contrast sensitivity of suppressed-by-contrast cells. A, B, Spatial frequency tuning of a representative cell (temporal frequency, 5 Hz; A) and the average curve for all cells (B; spatial frequency is normalized to the frequency of maximum suppression, on average 1.9 cycles/deg). Filled circles, Average discharge rate during presentation of a grating; open circles, amplitude of the modulated response at the frequency of stimulation (F1). Error bars show ±1 SEM. Dashed lines show the average rate of spontaneous discharge (top line) and the average spontaneous F1 (bottom line). Inset shows maintained discharge (gray line) and average response to passage of one cycle of the grating at each of two spatial frequencies (thin black line, 0 cycles/deg; thick black line, 8 cycles/deg). C, D, Temporal frequency tuning of the same cell as in A (spatial frequency, 3 cycles/deg; C) and the average curve for all cells (D), obtained using drifting gratings of the most suppressive spatial frequency. E, F, Response as a function of contrast for the same cell as in A, C (spatial frequency, 3 cycles/deg; temporal frequency, 9 Hz; E) and averaged over all cells (F). Other conventions are as in A.