Primary structural modules of the dorsal nuclei of the thalamus and motor cortex in humans.

The aim of the present work was to study the primary structure of the modular organization of neurons in the dorsal nucleus of the thalamus (ventral anterior, ventral lateral, anterior ventral, anterior medial, anterior dorsal, medial, reticular) and motor cortex (fields 4 and 6) in humans by the Nissl, Kluver-Barrera, and Golgi silver nitrate impregnation methods. These studies showed that neurons in the dorsal nuclei of the thalamus and the motor cortex are organized as small groups and short chains fulfilling defined criteria. These neuronal complexes, forming individual structural units, were termed primary structural modules. Comparison of primary structural modules in the dorsal nuclei and motor cortex showed that the principles of organization were identical in both locations. Thus, the dorsal nuclei of the thalamus and motor cortex in humans show two principles of the organization of neurons into primary structural modules: the group and chain principles.