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Synaptic inputs to two types of koniocellular pathway ganglion cells in marmoset retina
Author(s) -
Percival Kumiko A.,
Martin Paul R.,
Grünert Ulrike
Publication year - 2011
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.22586
Subject(s) - parvocellular cell , neuroscience , inner plexiform layer , retina , biology , lateral geniculate nucleus , giant retinal ganglion cells , parasol cell , marmoset , retinal ganglion cell , nucleus , paleontology
Abstract The retinal connectivity of the diverse group of cells contributing to koniocellular visual pathways (widefield ganglion cells) is largely unexplored. Here we examined the synaptic inputs onto two koniocellular‐projecting ganglion cell types named large sparse and broad thorny cells. Ganglion cells were labeled by retrograde tracer injections targeted to koniocellular layer K3 in the lateral geniculate nucleus in marmosets ( Callithrix jacchus ) and subsequently photofilled. Retinal preparations were processed with antibodies against the C‐terminal binding protein 2, the AMPA receptor subunit GluR4, and against CD15 to identify bipolar (excitatory) and/or antibodies against gephyrin to identify amacrine (inhibitory) input. Large sparse cells are narrowly stratified close to the ganglion cell layer. Broad thorny ganglion cells are broadly stratified in the center of the inner plexiform layer. Bipolar input to large sparse cells derives from DB6 and maybe other ON bipolar types, whereas that to broad thorny cells derives from ON and OFF bipolar cell types. The total number of putative synapses on broad thorny cells is higher than the number on large sparse cells but the density of inputs (between 2 and 5 synapses per 100 μm 2 dendritic area) is similar for the two cell types, indicating that the larger number of synapses on broad thorny cells is attributable to the larger membrane surface area of this cell type. Synaptic input density is comparable to previous values for midget‐parvocellular and parasol‐magnocellular pathway cells. This suggests functional differences between koniocellular, parvocellular, and magnocellular pathways do not arise from variation in synaptic input densities. J. Comp. Neurol. 519:2135–2153, 2011. © 2010 Wiley‐Liss, Inc.