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Encyclopedia > Ganglion cell

A ganglion cell (or sometimes called a gangliocyte) is a type of neuron located in the retina that receives visual information from photoreceptors via various intermediate cells such as bipolar cells, amacrine cells, and horizontal cells. Retinal ganglion cells’ axons are myelinated. The myelinated parts are outside the eye. These axons form the optic nerve and connect mainly to the lateral geniculate nucleus (LGN). Neurons (also spelled neurones or called nerve cells) are the primary cells of the nervous system. ... Human eye cross-sectional view. ... Photoreceptors are light-sensitive proteins involved in the function of photoreceptor cells. ... As a part of the retina, the bipolar cell exists between photoreceptors (rod cells and cone cells) and ganglion cells. ... Amacrine cell Retinal cell interneuron interacting at the Inner Plexiform Layer (IPL), the second synaptic retinal layer where bipolar cells and ganglion cells synapse. ... Horizontal cells are the laterally interconnecting neurons in the outer plexiform layer of the retina. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, which conducts electrical impulses away from the neurons cell body or soma. ... In neuroscience, myelin is an electrically insulating fatty layer that surrounds the axons of many neurons, especially those in the peripheral nervous system. ... The optic nerve is the nerve that transmits visual information from the retina to the brain. ... The lateral geniculate nucleus (LGN) of the thalamus is a part of the brain, which is the primary processor of visual information, received from the retina, in the CNS. Schematic diagram of the primate lateral geniculate nucleus. ...


There are about 1.2-1.5 million retinal ganglion cells in the human retina. With about 105 million photoreceptors per retina, on average each retinal ganglion cell receives inputs from about 100 rods and cones. Normalised absoption spectra of human rod (R) and cone (S,M,L) cells. ... Normalised absorption spectra of human cone (S,M,L) and rod (R) cells Cone cells, or cones, are cells in the retina which only function in relatively bright light. ...


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. Schematic of an electrophysiological recording of an action potential showing the various phases which occur as the wave passes a point on a cell membrane. ...


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

  • Parvocellular (P)
  • Magnocellular (M)
  • Koniocellular (K)
  • Other

Parvocellular retinal ganglion cells project to the parvocellular layers of the lateral geniculate nucleus. These cells are also known as midget retinal ganglion cells, confusingly abbreviated to M, based on the small sizes of their dendritic trees and cell bodies. About 80% of retinal ganglion cells are parvocellular cells. They receive inputs from relatively few rods and cones. They have slow conduction velocity, and respond only to high-contrast stimuli. In biology, a dendrite is a slender, typically branched projection of a nerve cell, or neuron, which conducts the electrical stimulation received from other cells to the body or soma of the cell from which it projects. ...


Magnocellular (M) retinal ganglion cells project to the magnocellular layers of the lateral geniculate nucleus. These cells are also known as parasol retinal ganglion cells, confusingly abbreviated to P, based on the large sizes of their dendritic trees and cell bodies. About 10% of retinal ganglion cells are magnocellular cells. They receive inputs from relatively many rods and cones. They have fast conduction velocity, and can respond to low-contrast stimuli. Umbrella An umbrella is a device used for temporary shade or shelter from precipitation. ...


Koniocellular (K) retinal ganglion cells project to the koniocellular layers of the lateral geniculate nucleus. Koniocellular 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 retinal ganglion cells are koniocellular cells. They receive inputs from relatively 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 colour vision.


Other retinal ganglion cells include cells that project to the LGN and cells that project to the suprachiasmatic nucleus (SCN). These retinal ganglion cells (Photosensitive Ganglion Cell) contain their own photopigment, melanopsin, meaning they respond directly to light in the eye. Cells projecting to the LGN include those making connections with the Edinger-Westphal nucleus (EW) for control of the pupillary light reflex and giant retinal ganglion cells. Cells projecting to the SCN go via the retinohypothalamic tract for setting and maintaining circadian rhythms. The suprachiasmatic nucleus (SCN) is a nucleus in the hypothalamus and is so named because it resides immediately above the optic chaism (OX). ... This article needs to be cleaned up to conform to a higher standard of quality. ... Photoreceptors are light-sensitive proteins involved in the function of photoreceptor cells. ... Melanopsin is a photopigment found in the ganglion cells of the retina that is involved in the regulation of Circadian rhythms. ... The Edinger-Westphal nucleus is the accessory parasympathetic nucleus of the oculomotor nerve, supplying the constricting muscles of the iris. ... Giant retinal ganglion cells were discovered in the human and macaque retina by Dacey et al. ... The Circadian rhythm is a name given to the internal body clock that regulates the (roughly) 24 hour cycle of biological processes in animals and plants. ...



Sensory system - Visual system - Eye - Retina

Rod cell - Cone cell - Bipolar cell - Amacrine cell - Horizontal cell - Ganglion cell (See also sense) A sensory system is a part of the nervous system that consists of sensory receptors, neural pathways, and those parts of the brain responsible for processing the information. ... The visual system is what allows us to see. ... An eye is an organ that detects light. ... Human eye cross-sectional view. ... Normalised absoption spectra of human rod (R) and cone (S,M,L) cells. ... Normalised absorption spectra of human cone (S,M,L) and rod (R) cells Cone cells, or cones, are cells in the retina which only function in relatively bright light. ... As a part of the retina, the bipolar cell exists between photoreceptors (rod cells and cone cells) and ganglion cells. ... Amacrine cell Retinal cell interneuron interacting at the Inner Plexiform Layer (IPL), the second synaptic retinal layer where bipolar cells and ganglion cells synapse. ... Horizontal cells are the laterally interconnecting neurons in the outer plexiform layer of the retina. ...


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