Amacrine cells

The Amacrine cells have no axons but their extensive neurites contribute properties of both the axons and dendrites. They are very diverse group morphologically, and most of the neurotransmitters specified in the nervous system are used by one or other of the 30 or so kinds of amacrine cell.

The Amacrine cells are implicated in surround inhibition, rod signaling, and detecting the direction of motion of an object across the visual field. Only the Dopaminergic amacrine cells are about 1% of all amacrine cells but their long dendrites interconnect, possibly through gap junctions to form a network. Such cells get input from the cone bipolar cells therefore the network is capable to signal average illumination that is used to produce surround inhibition. In the dark-adapted eye, the ganglion cells become very much sensitive to light as dopamine surround inhibition is turned off. A few of the ganglion cells are sensitive to the direction of motion of a stimulus. The direction sensitivity is conferred by amacrine cell circuits.