Border-ownership coding in the visual cortex. The bar graph on the right shows the responses (mean firing rate) of an area V2 neuron to the visual stimuli shown on the left. Ellipses mark the conventional receptive field of the neuron. In each case, the receptive field is stimulated with the same local edge, but in a different image context. Note that the neuron responds more strongly if that edge perceptually belongs to a figure on the lower left. We find border-ownership selectivity in about 50% of the cells in V2. Thus, although neurons of V2 have tiny receptive fields and signal local contour features (orientation, color gradient), they also code the global figure-ground relationship. The elusive ‘gestalt principles’ of perceptual organization have their correlates in the neural mechanisms of image segmentation.