The cuneus (plural: cunei) is a wedge-shaped region on the medial surface of the occipital lobe.
The parieto-occipital sulcus and calcarine sulcus join to form a "Y".
Blood supply to the cuneus is via the calcarine artery and parieto-occipital artery. The proportion varies from person to person and either artery can be the major source of perfusion .
Fibers of the superior optic radiation corresponding to the inferior quadrant of the visual field synapse on the cuneus .
Magneto encephalographic (MEG) measurements of occipital cortical signals have shown that the anteromedial cuneus activates almost simultaneously with the primary visual cortex (3-4 ms delay) in response to a visual stimulus and may act to modulate signals traveling from the primary visual cortex to the extrastriate cortices .
Lesions of the cuneus result in an inferior contralateral quadrantanopia .
Beyond its role in vision, a reduction of cortical thickness of the cuneus has also been associated with the pathogenesis of trigeminal neuralgia , as well as the development of psychosis in patients with a history of herpes simplex virus type 1 infection .
An MRI study found that thinning of posterior cortical regions, including the cuneus, is closely correlated with the occurrence and severity of visual hallucinations in dementia with Lewy bodies .