Optic radiation

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Brain: Optic radiation
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Deep dissection of cortex and brain-stem. (Optic radiation labeled at center left.)
Latin radiatio optica
NeuroNames ancil-529
Dorlands/Elsevier r_01/12686139

The optic radiation (also known as the geniculo-calcarine tract or as the geniculostriate pathway) is a collection of axons from relay neurons in the lateral geniculate nucleus of the thalamus carrying visual information to the visual cortex (also called striate cortex) along the calcarine fissure.

There is one such tract on each side of the brain.

Parts

A distinctive feature of the optic radiations is that they split into two parts on each side:

Source Path Information Damage
Fibers from the inferior retina (also called "Meyer's loop" or "Archambault's loop") must pass into the temporal lobe by looping around the inferior horn of the lateral ventricle. Carry information from the superior part of the visual field A lesion in the temporal lobe that results in damage to Meyer's loop causes a characteristic loss of vision in a superior quadrant (quadrantanopia.)
Fibers from the superior retina travel straight back to the occipital lobe in the retrolenticular limb of the internal capsule to the visual cortex. Carry information from the inferior part of the visual field Taking the shorter path, these fibers are less susceptible to damage.
File:Right superior quadrantanopia.png
Right superior quadrantanopia. The areas of the visual field lost in each eye are shown as black areas. This visual field defect is characteristic of damage to Meyer's loop on the left side of the brain.

Additional images

External links

nl:Geniculostriate route


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