p361fig10.10 Bipole grouping is achieved by long-range horizontal recurrent connections that also give rise to short-range inhibitory interneurons which inhibit nearby bipole cells as well as each other.<BR>||  Bipole property controls perceptual grouping. Collinear input on both sides.  Excitatory inputs summate. Inhibitory inputs normalize, Shunting inhibition!  Two-against-one.  Cell is excited.