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Inner S‐cone bipolar cells provide all of the central elements for S cones in macaque retina
Author(s) -
Herr Steve,
Klug Karl,
Sterling Peter,
Schein Stan
Publication year - 2003
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.10553
Subject(s) - retina , neuroscience , ribbon synapse , ganglion , biology , receptive field , growth cone , cone (formal languages) , anatomy , bistratified cell , axon , physics , giant retinal ganglion cells , retinal ganglion cell , synaptic vesicle , computer science , vesicle , genetics , algorithm , membrane
Synaptic terminals of cones ( pedicles ) are presynaptic to numerous processes that arise from the dendrites of many types of bipolar cell. One kind of process, a central element , reaches deeply into invaginations of the cone pedicle just below an active zone associated with a synaptic ribbon. By reconstruction from serial electron micrographs, we show that L‐ and M‐cone pedicles in macaque fovea are presynaptic to ∼20 central elements that arise from two types of inner (invaginating) bipolar cell, midget and diffuse. In contrast, S‐cone pedicles, with more synaptic ribbons, active zones/ribbon, and central elements/active zone, are presynaptic to ∼33 central elements. Moreover, all of these arise from one type of bipolar cell, previously described by others, here termed an inner S‐cone bipolar cell . Each provides ∼16 central elements. Thirty‐three is twice 16; correspondingly, these bipolar cells are twice as numerous as S cones. (Specifically, each S cone is presynaptic to four inner S‐cone bipolar cells; in turn, each bipolar cell provides central elements to two S cones.) These bipolar cells are presynaptic to an equal number of small‐field bistratified ganglion cells, giving cell numbers in 2G:2B:1S ratios. Each ganglion cell receives input from two or more inner S‐cone bipolar cells and thereby collects signals from three or more S cones. This convergence, along with chromatic aberration of short‐wavelength light, suggests that S‐cone contributions to this ganglion cell's coextensive blue‐ON/yellow‐OFF receptive field are larger than opponent L/M‐cone contributions via outer diffuse bipolar cells and that opponent L/M‐cone signals are conveyed mainly by inner S‐cone bipolar cells. J. Comp. Neurol. 457:185–201, 2003. © 2003 Wiley‐Liss, Inc.