Fig. 10.
The linear relation between l/‖v‖ and peak firing time is independent of background luminance or stimulus contrast, despite decreased responses at lower contrasts. A, Peak firing time relative to collision as a function of l/‖v‖ for four background luminances (B = 100%; 75, 50, and 25% of Imax = 95 cd/m2). Dashed line, Best linear fit for B = 75% (α = 4.20 ± 0.34; δ = 11.9 ± 6.6 msec). For clarity, only one linear fit is shown, and only the largest error for each value of l/‖v‖ is illustrated in one direction. B, Mean number of spikes ±SD elicited per trial for the same four background luminances as in A(symbols as in A). C, Peak firing time as a function of l/‖v‖ at four contrasts (C = −1.00, −0.75, −0.50, and −0.25). Dashed line, Best linear fit for C = −0.25 (α = 4.47 ± 1.56; δ = 17.9 ± 16.6 msec). D, Mean number of spikes ± SD elicited per trial for the same four contrasts as in C (symbols as in C). Data in A–D are from a single experiment.