網膜神経節細胞

WordNet

small room in which a monk or nun lives (同)cubicle
a device that delivers an electric current as the result of a chemical reaction (同)electric cell
a room where a prisoner is kept (同)jail cell, prison cell
(biology) the basic structural and functional unit of all organisms; they may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals
any small compartment; "the cells of a honeycomb"
a small unit serving as part of or as the nucleus of a larger political movement (同)cadre
an encapsulated neural structure consisting of a collection of cell bodies or neurons
in or relating to the retina of the eye; "retinal cells"
the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve

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(刑務所の)『独房』;(修道院の)小さい独居室 / (ミツバチの)みつ房,巣穴 / 小さい部屋 / 『細胞』 / 電池 / 花粉室 / (共産党などの)細胞
神経節・ガングリオン，結節腫《主に手首にできる良性の嚢腫(のうしゆ)》・〔知的･産業的活動の〕中心，中枢〔of〕
(目の)網膜

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/06 17:12:49」(JST)

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Diagram showing cross-section of retinal layers. The area labeled "Ganglionic layer" contains retinal ganglion cells.

A retinal ganglion cell (RGC) is a type of neuron located near the inner surface (the ganglion cell layer) of the retina of the eye. It receives visual information from photoreceptors via two intermediate neuron types: bipolar cells and retina amacrine cells. Retina amacrine cells, particularly narrow field cells, are important for creating functional subunits within the ganglion cell layer and making it so that ganglion cells can observe a small dot moving a small distance. ^[1] Retinal ganglion cells collectively transmit image-forming and non-image forming visual information from the retina in the form of action potential to several regions in the thalamus, hypothalamus, and mesencephalon, or midbrain.

Retinal ganglion cells vary significantly in terms of their size, connections, and responses to visual stimulation but they all share the defining property of having a long axon that extends into the brain. These axons form the optic nerve, optic chiasm, and optic tract.

A small percentage of retinal ganglion cells contribute little or nothing to vision, but are themselves photosensitive; their axons form the retinohypothalamic tract and contribute to circadian rhythms and pupillary light reflex, the resizing of the pupil.

The four types of retinal neurons are bipolar cells, ganglion cells, horizontal cells, and retina amacrine cells.

Function

There are about 1.2 to 1.5 million retinal ganglion cells in the human retina. With about 125 million ^[2] photoreceptors per retina, on average each retinal ganglion cell receives inputs from about 100 rods and cones. However, these numbers vary greatly among individuals and as a function of retinal location. In the fovea (center of the retina), a single ganglion cell will communicate with as few as five photoreceptors. In the extreme periphery (ends of the retina), a single ganglion cell will receive information from many thousands of photoreceptors.^{[citation needed]}

Retinal ganglion cells spontaneously fire action potentials at a base rate while at rest. Excitation of retinal ganglion cells results in an increased firing rate while inhibition results in a depressed rate of firing.

A false-color image of a flat-mounted rat retina viewed through a fluorescence microscope at 50x magnification. The optic nerve was injected with a fluorophore, causing retinal ganglion cells to fluoresce.

Types

Three groups

W-ganglion- small, 40% of total, broad fields in retina, excitation from rods, detect direction movement anywhere in the field.
X-ganglion- medium diameter, 55% of total, small field, colour vision. Sustained response.
Y- ganglion cells- largest, 5%, very broad dendritic field, respond to rapid eye movement or rapid change in light intensity. Transient response.

Based on their projections and functions, there are at least five main classes of retinal ganglion cells:

Midget cell (Parvocellular, or P pathway; P cells)
Parasol cell (Magnocellular, or M pathway; M cells)
Bistratified cell (Koniocellular, or K pathway)
Photosensitive ganglion cells
Other ganglion cells projecting to the superior colliculus for eye movements (saccades)^[3]

Midget

Midget retinal ganglion cells project to the parvocellular layers of the lateral geniculate nucleus. These cells are known as midget retinal ganglion cells, based on the small sizes of their dendritic trees and cell bodies. About 80% of all retinal ganglion cells are midget cells in the parvocellular pathway. They receive inputs from relatively few rods and cones. In many cases, they are connected to midget bipolars, which are linked to one cone each.^[4] They have slow conduction velocity, and respond to changes in color but respond only weakly to changes in contrast unless the change is great (Kandel et al., 2000). They have simple center-surround receptive fields, where the center may be either ON or OFF while the surround is the opposite.

Parasol

Parasol retinal ganglion cells project to the magnocellular layers of the lateral geniculate nucleus. These cells are known as parasol retinal ganglion cells, based on the large sizes of their dendritic trees and cell bodies. About 10% of all retinal ganglion cells are parasol cells, and these cells are part of the magnocellular pathway. They receive inputs from relatively many rods and cones. They have fast conduction velocity, and can respond to low-contrast stimuli, but are not very sensitive to changes in color (Kandel et al., 2000). They have much larger receptive fields which are nonetheless also center-surround.

Bistratified

Bistratified retinal ganglion cells project to the koniocellular layers of the lateral geniculate nucleus. Bistratified retinal ganglion cells have been identified only relatively recently. Koniocellular means “cells as small as dust”; their small size made them hard to find. About 10% of all retinal ganglion cells are bistratified cells, and these cells go through the koniocellular pathway. They receive inputs from intermediate numbers of rods and cones. They have moderate spatial resolution, moderate conduction velocity, and can respond to moderate-contrast stimuli. They may be involved in color vision. They have very large receptive fields that only have centers (no surrounds) and are always ON to the blue cone and OFF to both the red and green cone.

Photosensitive ganglion cell

Photosensitive ganglion cells, including but not limited to the giant retinal ganglion cells, contain their own photopigment, melanopsin, which makes them respond directly to light even in the absence of rods and cones. They project to, among other areas, the suprachiasmatic nucleus (SCN) via the retinohypothalamic tract for setting and maintaining circadian rhythms. Other retinal ganglion cells projecting to the lateral geniculate nucleus (LGN) include cells making connections with the Edinger-Westphal nucleus (EW), for control of the pupillary light reflex, and giant retinal ganglion cells.

Retinal ganglion cell physiology

Most mature ganglion cells are able to fire action potentials at a high frequency because of their expression of K_v3 potassium channels.^[5]^[6]^[7]

Myelination

In most mammals, the axons of retinal ganglion cells are not myelinated where they pass through the retina. However, the parts of axons that are beyond the retina, are myelinated. This myelination pattern is functionally explained by the relatively high opacity of myelin — myelinated axons passing over the retina would absorb some of the light before it reaches the photoreceptor layer, reducing the quality of vision. There are human eye diseases where this does, in fact, happen. In some vertebrates, for example the chicken, the ganglion cell axons are myelinated inside the retina.^[8]

References

^ Masland, R. H. (2012). "The tasks of amacrine cells". Visual neuroscience 29 (1): 3–9. PMC 3652807. PMID 22416289. edit
^ "Hecht, Eugene, Optics, 2nd Ed, Addison Wesley, 1987
^ Principles of Neural Science 4th Ed. Kandel et al.
^ "eye, human."Encyclopædia Britannica. 2008. Encyclopædia Britannica 2006 Ultimate Reference Suite DVD
^ http://ykolodin.50webs.com/
^ Henne,J.; Pottering,S.; Jeserich,G. (2000). "Voltage-gated potassium channels in retinal ganglion cells of trout: a combined biophysical, pharmacological, and single-cell RT-PCR approach". J.Neurosci.Res. 62 (5): 629–637. doi:10.1002/1097-4547(20001201)62:5<629::AID-JNR2>3.0.CO;2-X. PMID 11104501.
^ Henne,J.; Jeserich,G. (2004). "Maturation of spiking activity in trout retinal ganglion cells coincides with upregulation of Kv3.1- and BK-related potassium channels". J.Neurosci.Res. 75 (1): 44–54. doi:10.1002/jnr.10830. PMID 14689447.
^ Villegas, G.M. (1960). "Electron microscopic study of the vertebrate retina". J. Gen. Physiol. 43 (6): 15–43. doi:10.1085/jgp.43.6.15.

External links

Diagram at mit.edu
Overview and diagrams at webexhibits.org
Neuronbank Wiki page on RGCs
NIF Search - Retinal Ganglion Cell via the Neuroscience Information Framework

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English Journal

Effect of botulinum toxin A on the intraocular pressure and the retina in an animal model.

Gatzioufas Z, Stupp T, Moschos MM, Kopsidas K, Charalambous P, Thanos S.SourceInstitute of Experimental Ophthalmology, University of Muenster, Muenster, Germany. zisis.gkatzioufas@uks.eu
Cutaneous and ocular toxicology.Cutan Ocul Toxicol.2013 Jun;32(2):107-11. doi: 10.3109/15569527.2012.713419. Epub 2012 Aug 24.
OBJECTIVE: The purpose of our study was to investigate the effect of an inadvertent intravitreal injection of botulinum toxin A (BTA) on the intraocular pressure (IOP) and the retina in an animal model.METHODS: BTA was injected intravitreally in normotensive rats. IOP was measured preoperatively as
PMID 22917001

A novel optineurin truncating mutation and three glaucoma-associated missense variants in patients with familial amyotrophic lateral sclerosis in Germany.

Weishaupt JH, Waibel S, Birve A, Volk AE, Mayer B, Meyer T, Ludolph AC, Andersen PM.SourceDepartment of Neurology, Ulm University, Ulm, Germany. jochen.weishaupt@uni-ulm.de
Neurobiology of aging.Neurobiol Aging.2013 May;34(5):1516.e9-15. doi: 10.1016/j.neurobiolaging.2012.09.007. Epub 2012 Oct 10.
Mutations in the optineurin (OPTN) gene have been associated with normal tension glaucoma and with amyotrophic lateral sclerosis (ALS). Here, we screened German familial ALS cases for OPTN mutations to gain additional insight into the spectrum and pathogenic relevance of this gene for ALS. One hundr
PMID 23062601

A quantitative analysis of branching, growth cone turning, and directed growth in zebrafish retinotectal axon guidance.

Simpson HD, Kita EM, Scott EK, Goodhill GJ.SourceQueensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Australia.
The Journal of comparative neurology.J Comp Neurol.2013 Apr 15;521(6):1409-29. doi: 10.1002/cne.23248.
The topographic projection from the eye to the tectum (amphibians and fish)/superior colliculus (birds and mammals) is a paradigm model system for studying mechanisms of neural wiring development. It has previously been proposed that retinal ganglion cell axons use distinct guidance strategies in fi
PMID 23124714

Japanese Journal

Macular thickness changes in a patient with Leber's hereditary optic neuropathy

Mizoguchi Ayako,Hashimoto Yuki,Shinmei Yasuhiro,Nozaki Mayo,Ishijima Kan,Tagawa Yoshiaki,Ishida Susumu
BMC ophthalmology 15, 27, 2015-03-18
… Background: Leber's hereditary optic neuropathy (LHON) refers to an optic nerve dysfunction due to mutations in the mitochondrial DNA, resulting in visual loss by apoptosis of retinal ganglion cells (RGC). … There are some reports regarding the circumpapillary retinal nerve fiber layer (cpRNFL) and the ganglion cell analysis around the macula in LHON patients and carriers by using optical coherence tomography. …
NAID 120005606032