[NADPH-diaphorase positive cells of the human thalamic nuclei and internal capsule]

Isolated NADPH-diaphorase (NADPH-d)-positive neurons were demonstrated in the nuclei of human dorsal thalamus and nucleus reticularis. Staining of NADPH-d-positive neurons with all their processes and preceding study of neurons of dorsal thalamus using Golgi method enabled the identification of their types and their determination as sparsely-branched cells. Main types of efferent densely-branched neurons had no demonstrable NADPH-d activity. NADPH-d-positive neurons were represented by reticular neurons and by one type of short-axon interneurons. Capsula interna contains numerous NADPH-d-positive reticular neurons. NADPH-d-positive cells forming contacts with blood vessels were found. Thus, NADPH-d-positive cells of dorsal thalamus, reticular nucleus and capsula interna appear to be evolutionally more ancient and structurally less complex.