p374fig11.04 The three processing stages of monocular simple cells, and complex cells accomplish both contrast-specific binocular fusion and contrast-invariant boundary perception.<BR>||  Model unifies contrast-specific binocular fusion and contrast-invariant boundary perception (Ohzawa etal 1990; Grossberg, McLoughlin 1997). [Left, right] eye V1-4 simple cells-> V1-3B simple cells-> V1-2/3A complex cells.  Contrast-specific stereoscopic fusion by disparity-selective simple cells.  Contrast-invariant boundaries by pooling opposite polarity binocular simple cells at complex cells layer 2/3A.