Figure 8.

Change in CRF response onset latency with contrast. A, Response onset latencies for stimuli driving the CRF alone are shown for C₅₀ and C₉₀ contrasts. The latency was determined to be the first time point where the stimulus-driven cumulative spike count was significantly greater than that of the spontaneous activity (see Materials and Methods). With lower contrast (C₅₀) the response onset latencies increase, as shown by the points lying below the unity line. B, Histogram of the difference in onset latency between the C₅₀ and C₉₀ conditions. The average increase in latency due to lowering of stimulus contrast from C₉₀ to C₅₀ was 20 ms.