Radial time space plots. Radial histograms were performed on OIS data at all stimulus amplitudes. Radii were measured from the center of activation as demonstrated in the image at top-left. The dashed blue line is the maximum radial distance used in the maps shown. The schematic at bottom left indicates the anatomical orientation of the cortex in the image above. Absorbance values in maps shown represent an average at each radial distance at each frame after stimulus onset. Green arrows indicate stimulus onset (1s) while red arrows indicate stimulus offset (11s). Absorbance values are color coded as per the color bar shown at the right.