Push-pull modulation of ganglion cell responses of carp retina by amacrine cells. 
The responses of a ganglion and an amacrine cell were recorded simultaneously in the carp retina.  Sinusoidal current injected into amacrine cells modulated ganglion cell discharges either in phase (excitation) or in opposite phase (inhibition).  ON-center ganglion cells received excitatory inputs and OFF-center ganglion cells received inhibitory inputs from ON-center amacrine cells.  They received inputs of opposite polarity from OFF-center amacrine cells.  Namely, inputs from ON-center and OFF-center amacrine cells augment the responses of ON-center and OFF-center ganglion cells in a push-pull manner.