Interactions between orientations in human vision

Single lines cause changes in the apparent orientation of nearby lines of somewhat different orientation: acute angles are perceptually expanded while obtuse angles apparently contract. This phenomenon is measured by a matching technique and evidence is presented that it is due to recurrent, inhibitory interactions among orientation selective neural channels. In particular, a third line added to an angle figure can have a disinhibiting effect on the orientational distortion. Orientation selective channels maximally sensitive to different orientations may have different distributions of inhibitory input in the orientation domain. The results are interpreted in terms of the organization of neurones in the visual cortex. Each cell may receive a crude orientation selectivity from its direct input, and be inhibited, over an even broader range of orientation, by neurones in the same column and adjacent ones. © 1973 Springer-Verlag.