
Plan of retinal neurons.
'Amacrine cells' are
interneurons in the
retina which deliver 70% of the ganglion cells input, and also regulates the output of the cone bipolar cells which deliver the other 30%.
Overview
Amacrine cells operate at the
inner plexiform layer (IPL), the second synaptic retinal layer where
bipolar cells and
ganglion cells
synapse. There are about 40 different types of amacrine cells, most lacking
axons. Like horizontal cells, amacrine cells work laterally affecting the output from bipolar cells, however, their tasks are often more specialized. Each type of amacrine cell connects with a particular type of bipolar cell, and generally has a particular type of
neurotransmitter. One such population, AII, 'piggybacks' rod bipolar cells onto the cone bipolar circuitry. It connects rod bipolar cell output with cone bipolar cell input, and from there the signal can travel to the respective ganglion cells.
They are classified by the width of their field of connection, which layer(s) of the stratum in the IPL they are in, and by neurotransmitter type. Most are inhibitory using either
GABA or
glycine as
neurotransmitters.
Functionality
Functionally, they are responsible for complex processing of the retinal
image, specifically adjusting image
brightness and, by integrating sequential activation of neurons, detecting
motion.
See also
★
Photoreceptor cell
★
Horizontal cell
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Bipolar cell
★
Ganglion cell
References
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From Neuron to Brain, , John G., Nicholls, Sinauer Associates, Inc, ,
★
The fundamental plan of the retina, Masland RH, , , Nat. Neurosci., 2001
External links
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Webvision amacrine cell article
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