Midget cell

Midget cell
A sketch of a parasol cell (right) alongside a midget cell (left) for size comparison
Details
Part of	Retina of eye
System	Visual system
Identifiers
FMA	62360
Anatomical terminology [edit on Wikidata]

A midget cell is one type of retinal ganglion cell (RGC). Midget cells originate in the ganglion cell layer of the retina, and project to the parvocellular layers of the lateral geniculate nucleus (LGN). The axons of midget cells travel through the optic nerve and optic tract, ultimately synapsing with parvocellular cells in the LGN. These cells are known as midget retinal ganglion cells due to the small sizes of their dendritic trees and cell bodies. About 80% of RGCs are midget cells. They receive inputs from relatively few rods and cones. In many cases, they are connected to midget bipolar cells, which are linked to one cone each.^[1]

These neurons show roughly circular receptive fields with antagonistic center and surround; this property is known as spatial opponency and these neurons are typically divided into ON- or OFF-center, depending on whether they are excited or inhibited by photons falling on the center of their receptive fields.^[2] Most of these cells are chromatically opponent, meaning that long- and medium-wavelength visible light (commonly approximated to red and green, respectively) exert opposing effects on the center and the surround.^[2] For instance, a chromatically opponent L-ON midget cell would be excited (and more likely to spike action potentials) if light of long wavelength falls on the cone or cones in the center of its receptive field but would be inhibited by medium-wavelength light falling on the surround of its receptive field.^[2] However, not all midget cells are chromatically opponent.^[2]

They have slow conduction velocity and are very responsive to high temporal frequencies (i.e. rapidly and low spatial frequencies).^[3]

See also

• Bistratified cell
• Parasol cell
• Photosensitive ganglion cell

References

External links

• Media related to Midget cell at Wikimedia Commons

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Anatomy of the globe of the human eye

Fibrous tunic
(outer)

Sclera	Episcleral layer Schlemm's canal Trabecular meshwork
Cornea	Limbus layers Epithelium Bowman's Stroma Dua's layer Descemet's Endothelium

Uvea / vascular
tunic (middle)

Choroid	Capillary lamina of choroid Bruch's membrane Sattler's layer
Ciliary body	Ciliary processes Ciliary muscle Pars plicata Pars plana
Iris	Stroma Pupil Iris dilator muscle Iris sphincter muscle

Retina (inner)

Layers	Inner limiting membrane Nerve fiber layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer External limiting membrane Layer of rods and cones Retinal pigment epithelium
Cells	Photoreceptor cells (Cone cell, Rod cell) → (Horizontal cell) → Bipolar cell → (Amacrine cell) → Retina ganglion cell (Midget cell, Parasol cell, Bistratified cell, Giant retina ganglion cells, Photosensitive ganglion cell) → Diencephalon: P cell, M cell, K cell, Muller glia
Other	Macula Perifoveal area Parafoveal area Fovea Foveal avascular zone Foveola Optic disc Optic cup Ora serrata

Anatomical regions
of the eye

Anterior segment	Adnexa (Eyebrow, Eyelid, Conjunctiva, Lacrimal system, Orbit) Fibrous tunic Anterior chamber Aqueous humour Iris Posterior chamber Ciliary body Lens Capsule of lens Zonule of Zinn
Posterior segment	Vitreous chamber Vitreous body Retina Choroid

Other

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• Eye care professional
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• Physiological Optics
• Visual perception