ANOVA p -values. p-values for the two-way ANOVA as a function of time, for the significance of the stimulus effect (top panel) and for the significance of the difference in orientation selectivity (bottom panel). p-values obtained using the distribution (red), direct bootstrap (black) and χ2-based bootstrap from the appendix (green) are shown. p-values below the horizontal dotted line (constant value 0.05) are significant. The vertical dotted lines depict the stimulation times.