[Structural organization of pedunculopontine tegmental nucleus in the dog's midbrain].

The aim of this study was to determine the borders of pedunculopontine tegmental nucleus (PPN) in the dog's brain and to describe its individual substructures on the basis of the cytoarchitectonic study of this nucleus. Using the methods of Nissl, Kluver-Barrera and histochemical demonstration of NADPH-diaphorase, which is a selective marker of cholinergic neurones of tegmental area, the analysis of fiber organization, morphological types of neurons and density of their distribution in PPN was carried out. As a result, mapping this nucleus in dog's brain was performed and the borders of its parts including a compact and a diffuse one were described. It was not possible to distinguish mesencephalic extrapyramidal area from the general composition of PPN.