Neuronal types in the claustrum of man.

Neuronal types of the human claustrum have been investigated by means of a transparent Golgi technique which enables one to study the characteristics of not only the cellular processes but also the marking features of the nuclei, the cellular organelles, and the paraplasmic substances of various types of nerve cells. Five varieties of neurons have been distinguished: Type I represents a class of spiny nerve cells varying to a certain extent in size and shape. These cells contain fine and widely dispersed lipofuscin granules which can only faintly be tinged by aldehydefuchsin. Type II cells are large aspiny neurons. Their cell bodies contain a great number of deeply stained coarse pigment granules. Type III cells are large aspiny neurons devoid of pigment deposits. Type IV is a small pigment-laden aspiny neuron. Type V is a small aspiny neuron devoid of lipofuscin granules. The pattern of pigmentation revealed by the different types of nerve cells turns out to be highly characteristic. It can well be used for classification of the various types of nerve cells which occur within the reaches of the claustrum.