Optic radiation

Optic radiation
Colour-coded diagram showing radiations in quadrants from retinal disc through the brain
Details
Identifiers
Latin	radiatio optica
NeuroNames	ancil-529
Dorlands /Elsevier	r_01/12686139
TA	A14.1.08.673 A14.1.09.542 A14.1.09.547
FMA	61941
Anatomical terms of neuroanatomy []

The optic radiation (also known as the geniculocalcarine tract, the geniculostriate pathway, and posterior thalamic radiation) are axons from the neurons in the lateral geniculate nucleus to the primary visual cortex. The optic radiation receives blood through deep branches of the middle cerebral artery and posterior cerebral artery.

They carry visual information through two divisions (called upper and lower division) to the visual cortex (also called striate cortex) along the calcarine fissure. There is one such tract on each side of the brain. If a lesion only exists in one optic radiation, the consequence is called quadrantanopia, which implies that only the respective superior or inferior quadrant of the visual field is affected.

The upper division:

The lower division:

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

The optic radiation contains tracts which transmit visual information from the retina of the eye to the visual cortex. Lesions of the optic radiations are usually unilateral and commonly vascular in origin. Field defects therefore develop abruptly, in contrast to the slow progression of defects associated with tumors.

Tracts contained within the optic radiation are examined as part of a cranial nerve examination.

Horizontal section of right cerebral hemisphere.

Diagram of the tracts in the internal capsule.

3D schematic representation of optic tracts