FIGURE 13: Schematic representation of the texture filling-in stimulus used by De Weerd et al. (1995) in their comparison of perceptual filling-in and cortical cell responses.

Human subjects were asked to fixate the fixation point (FP) and indicate when they saw the hole fill in by releasing a button. Under similar stimulation conditions, cortical cell responses were measured for cells in V2 and V3 of the primate visual cortex.