Configuration of the magnocellular nuclei in the basal forebrain of the human adult.

Abstract

With the use of gapless series of thick sections (800 microns) stained for lipofuscin pigment as a stable intraneuronal characteristic, it was found in the human brain that the three magnocellular nuclei in the basal forebrain-the medial septal nucleus, the nucleus of the diagonal band (vertical and horizontal limb) and the basal nucleus of Meynert located within the substantia innominata-were tightly connected with each other. A band-like anteromedial subnucleus and a semilunar posterolateral subnucleus could be delineated in the basal nucleus and were found to be embedded in a zone of low cell density, the substantia innominata, which medially blends into the horizontal limb of the diagonal band nucleus. A three-dimensional reconstruction was made to demonstrate the complex shape of the magnocellular basal forebrain nuclei.