The area, one more hay. and one more left. about the midline, is located on the underside of the brain. It is included in the basal forebrain (basal fore-brain) and is located there between the inner and outer olfactory strands (stria olfactoria medialis and s.o.lateralis). Here, the surface of the brain is pierced/perforated by numerous small but very clear holes; inlet for a bundle of narrow arteries (the anterior outer central/perforating cerebral arteries from the middle cerebral artery and the anterior inner central/perforating cerebral arteries from the anterior cerebrum artery). These blood vessels must supply parts of the nuclei of the lens and tail (nucleus lentiformis and caudate nucleus), parts of the inner filament capsule (capsula interna) and parts of the pile of vision (thalamus).
The arteries that enter the brain via the substantia perforata anterior include the thalamostriata artery and the lenticulostriata artery. The vessels are often attacked by atherosclerosis (arteriosclerosis) and, when they become clogged or rupture, give rise to a severe form of stroke where the opposite half of the body becomes more or less paralyzed. This includes the classic 'Capsula internal bleeding'.