Starburst cells nondirectionally facilitate the responses of direction-selective retinal ganglion cells.
The mechanism of direction selectivity in retinal ganglion cells remains controversial. An important issue is how the starburst amacrine cells, which are known to provide a major synaptic input to the direction-selective ganglion cells, participate in the directional discrimination. Here, we present evidence that the cholinergic outputs of the starburst cells affect the responses of the ganglion cells symmetrically; they provide a feedforward excitation that facilitates the response of the ganglion cells to movement in both the preferred and null directions. This seems to place a constraint on models of the directional discrimination in which the starburst cells participate, namely, that their cholinergic synapses be nondirectional in their effects on the ganglion cells.
Chiao
Chuan-Chin
CC
Howard Hughes Medical Institute, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
Masland
Richard H
RH
D025042:Amacrine Cells / Q000502:physiology*; D000818:Animals; D002450:Cell Communication; D046508:Culture Techniques; D005074:Evoked Potentials, Visual; D018756:GABA Antagonists / Q000494:pharmacology; D009039:Motion Perception; D018733:Nicotinic Antagonists / Q000494:pharmacology; D010852:Picrotoxin / Q000494:pharmacology; D011817:Rabbits; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission; D014403:Tubocurarine / Q000494:pharmacology; D014794:Visual Fields; D014795:Visual Pathways
D018756:GABA Antagonists; D018733:Nicotinic Antagonists; D010852:Picrotoxin; D014403:Tubocurarine