Fig. 5
From: Contrast and luminance adaptation alter neuronal coding and perception of stimulus orientation
Psychophysical measurement of orientation discrimination. a The experimental paradigm. Each trial consisted of a short movie of rapidly presented sinusoidal gratings with random orientations and phases (each for two monitor frames, 16.7 ms). Subjects fixated on the cross throughout the trial. Subjects performed an orientation discrimination task after which the contrast (luminance) of the gratings changed to a higher contrast (lower luminance). The orientation discrimination was performed either 0.2–1.2 s (early trials) or 5–6 s (late trials) after the switch. b, c Psychometric data with cumulative Gaussian fit for a single subject performing the contrast- (b) and luminance-increment (c) tasks. d–g Comparison of discrimination thresholds for early and late phases of four different luminance- and contrast-adaptation conditions (the number of participants from (d–g): n = 7, 7, 14, and 8). The small arrow in (d) and (f) refers to the participant on the left, and the red circle shows the average threshold. Error bars show bootstrap standard deviation
