Fig. 1.

Schematic examples of three models of binocular simple cells: a, position-based model; b, phase-based model; and c, subregion correspondence. In each case, light and dark regions represent ON- and OFF-type subregions in the overlapping left- and right-eye RFs of a single cell. The key points illustrated are the phase of each eye’s RF relative to its center and the position shift along the axis perpendicular to the preferred orientation. RFs are displaced along the preferred orientation axis for simpler display; displacements in this direction are unconstrained in the phase-based and subregion correspondence models.