Anoxic encephalopathy occurs in settings of poor cerebral oxygenation - this is distinguished from poor overall cerebral perfusion, which causes cerebral infarcts (strokes), first in a watershed pattern.
Note that from a pathologic standpoint, CA1 of the cornu ammonis (of the hippocampus) forms the largest stretch of Ammon's horn and is distinctly susceptible to cerebral anoxia; although, as we see in these images, it is the cerebral cortex that first demonstrates signs of injury on MRI imaging.
Relevant anatomical links:
Basal ganglia
Thalami
Insular cortex