Microcircuitry for Two Types of Achromatic Ganglion Cell in Primate Fovea.
From: Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA. david.j.calkins@vanderbilt.edu
The Journal of neuroscience : the official journal of the Society for Neuroscience
- Publish Date: Mar 2007
- ISSN: 1529-2401
- Volume: 27
- Issue: 10
- Pages: 2646-53
- Medium: Internet
- Language: English
- Citation (JAMA): Calkins David J, Sterling Peter, et al. Microcircuitry for Two Types of Achromatic Ganglion Cell in Primate Fovea.. J. Neurosci. Mar 2007;27:2646-53
Abstract
Synaptic circuits in primate fovea have been quantified for midget/parvocellular ganglion cells. Here, based on partial reconstructions from serial electron micrographs, we quantify synaptic circuits for two other types of ganglion cell: the familiar parasol/magnocellular cell and a smaller type, termed “garland.” The excitatory circuits both derive from two types of OFF diffuse cone bipolar cell, DB3 and DB2, which collected unselectively from at least 6 +/- 1 cones, including the S type. Cone contacts to DB3 dendrites were usually located between neighboring triads, whereas half of the cone contacts to DB2 were triad associated. Ribbon outputs were as follows: DB3, 69 +/- 5; DB2, 48 +/- 4. A complete parasol cell (30 microm dendritic field diameter) would collect from approximately 50 cones via approximately 120 bipolar and approximately 85 amacrine contacts; a complete garland cell (25 microm dendritic field) would collect from approximately 40 cones via approximately 75 bipolar and approximately 145 amacrine contacts. The bipolar types contributed differently: the parasol cell received most contacts (60%) from DB3, whereas the garland cell received most contacts (67%) from DB2. We hypothesize that DB3 is a transient bipolar cell and that DB2 is sustained. This would be consistent with their relative inputs to the brisk-transient (parasol) ganglion cell. The garland cell, with its high proportion of DB2 inputs plus its high proportion of amacrine synapses (70%) and dense mosaic, might correspond to the local-edge cell in nonprimate retinas, which serves finer acuity at low temporal frequencies. The convergence of S cones onto both types could contribute S-cone input for cortical areas primary visual cortex and the middle temporal area.
Mesh Headings (Keywords): Amacrine Cells, Animals, Cell Communication, Cones (Retina), Dendrites, Fovea Centralis, Image Processing, Computer-Assisted, Macaca fascicularis, Male, Microscopy, Electron, Neural Pathways, Retinal Bipolar Cells, Synapses
Check for Full Text / PubMed Unique Identifier (PMID): 17344402
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