Article ID Journal Published Year Pages File Type
4321863 Neuron 2010 14 Pages PDF
Abstract

SummaryStarburst amacrine cells (SACs) process complex visual signals in the retina using both acetylcholine (ACh) and gamma-aminobutyric acid (GABA), but the synaptic organization and function of ACh-GABA corelease remain unclear. Here, we show that SACs make cholinergic synapses onto On-Off direction-selective ganglion cells (DSGCs) from all directions but make GABAergic synapses onto DSGCs only from the null direction. ACh and GABA were released differentially in a Ca2+ level-specific manner, suggesting the two transmitters were released from different vesicle populations. Despite the symmetric cholinergic connection, the light-evoked cholinergic input to a DSGC, detected at both light onset and offset, was motion- and direction-sensitive. This input was facilitated by two-spot apparent motion in the preferred direction but supressed in the null direction, presumably by a GABAergic mechnism. The results revealed a high level of synaptic intricacy in the starburst circuit and suggested differential, yet synergistic, roles of ACh-GABA cotransmission in motion sensitivity and direction selectivity.

► Detected ACh-GABA synaptic cotransmission in the retina ► Discovered symmetric ACh and asymmetric GABA circuits in the starburst network ► Discovered differential regulation of ACh and GABA releases from starburst cells ► Revealed a role of ACh-GAB corelease in motion sensitivity and direction selectivity

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