The types of neurons in the claustrum of bison bonasus: Nissl and Golgi study

The Nissl staining and Golgi impregnation methods has been used to characterize the types of neurons in the claustrum of bison bonasus. Two fairly divergent subpopulations of cells can be distinguished by means of Golgi preparation technique. The first group--comprising the bulk of claustral neurons--is composed of only one type of large, efferent nerve cells with long axons and dendrites covered with spines. The somata and initial portion of dendritic processes are devoid of spines. The second group consists of large and medium-size interneurons with smooth infrequently branching dendrites. Amongst them two sub-populations can be observed: with dendritic swellings and with dendrites deveoid of them. In Nissl stained sections the claustral neuronal population consists of large multipolar cells among which fewer large or medium-size, spindle-shaped cells are dispersed. The multipolar cells and also spindle-shaped neurons contain widely distributed, deeply-stained, medium-sized pigment granules. No orderly alignment of cells can be seen.