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an·te·ri·or per·fo·rat·ed sub·stance[TA]
a region at the base of the brain through which numerous small branches of the anterior and middle cerebral arteries (lenticulostriate arteries) enter the depth of the cerebral hemisphere; it is bordered medially by the optic chiasm and anterior half of the optic tract rostrally and laterally by the lateral olfactory stria; its anteromedial part corresponds to the olfactory tubercle.
The space pierced by blood vessels at the base of the brain.
See also: space