Fig. 3. Response as a function of contrast of Gaussian windowed sinusoidal grating (Gabor patch). (A) Single trials showing responses to traditional `contrast step' stimulus. (B) `Contrast ramp' stimulus measures contrast-response relationship more rapidly. Blue line shows mean response and gray fill shows mean response ± instantaneous s.d. (C) Comparison of methods shown in A and B plotted on logarithmic contrast axis. Smooth red line shows analytic fit to contrast ramp data. Data are from frontal portion of the receptive field of a single male HSN cell viewing sinusoidal grating at 0.1 cycles deg.^-1 at 5 Hz. Values are means ± s.d. from at least 3 trials. Az, azimuth; El, elevation.