Role of ACh-GABA cotransmission in detecting image motion and motion direction

Neuron. 2010 Dec 22;68(6):1159-72. doi: 10.1016/j.neuron.2010.11.031.


Starburst 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 Ca(2+) 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 mechanism. 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.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / physiology*
  • Amacrine Cells / physiology
  • Animals
  • Motion Perception / physiology*
  • Photic Stimulation / methods
  • Rabbits
  • Retina / physiology*
  • Synapses / physiology
  • Synaptic Transmission / physiology*
  • gamma-Aminobutyric Acid / physiology*


  • gamma-Aminobutyric Acid
  • Acetylcholine