[Characterization of the neurons of the basal forebrain complex in the rat: A Nissl- and Golgi impregnation study].

Nissl stained neurons were classified in some nuclei of the basal forebrain complex of the rat (Nc. septi medialis, MS; vertical limb of the nucleus of the diagonal band, vDB; horizontal limb of the nucleus of the diagonal band, hDB; Nc. preopticus magnocellularis, NPM; Substantia innominata, SI; Nc. basalis Meynert, NB). Several types of neurons are coexistent in each of these nuclei. They differ in soma size and shape, but also in their cytoplasmic and nuclear texture. We found three classes of neurons as well in the MS-vDB, as in the hDB and NPM, but five classes in the SI-NB complex. On the basis of these findings some conclusions were drawn regarding the cytoarchitecture of this region, as the demarcation of vDB and hDB and of hDB and NPM. The borderline between vDB and hDB was found to be undefinable in Nissl stained preparations, whereas the NPM is characterized by its high content of giant neurons in cotontrast the adjacent hDB. Additionally, we tried to identify the Nissl stained neurons on the basis of soma features with Golgi impregnated neurons. The daimpregnations of Golgi impregnated neurons enabled us to compare the width of the cytoplasm and the nuclear position of neurons stained after these methods. From the thirteen classes of neurons described in Golgi investigations, 8 were identified in Nissl stained sections through this region of the rat's forebrain.