Posterior cerebral artery syndrome is a condition whereby the blood supply from the posterior cerebral artery (PCA) is restricted, leading to a reduction of the function of the portions of the brain supplied by that vessel: the occipital lobe, the inferomedial temporal lobe, a large portion of the thalamus, and the upper brainstem and midbrain.

[2] Depending upon the location and severity of the occlusion, signs and symptoms may vary within the population affected with PCA syndrome.

Blockages of the proximal portion of the vessel produce only minor deficits due to the collateral blood flow from the opposite hemisphere via the posterior communicating artery.

Visual deficits, such as agnosia, prosopagnosia or cortical blindness (with bilateral infarcts) may be a product of ischemic damage to occipital lobe.

[1] Left posterior cerebral artery syndrome presents alexia without agraphia; the lesion is in the splenium of the corpus callosum.