Quantitative histological studies on the lateral geniculate nucleus in the cat. III. Distribution of different types of neurons in the several layers of LGN.

An attempt is made on the definition of proportional distribution of the different types of neurons in the layers of LGN by means of quantitative method. On the basis of nuclear volume, nuclear and cell diameters the different types of neurons were separated according to their size and shape. The ratio of relay and interneurons proved to be 2:1 in all layers of LGN of cat. The proportional distribution of further subgroups of neurons was also defined. The bilateral connections between the relay and interneurons based on initial axon collateral of TCR neurons and on axon terminals and dendritic appendages of INs, are also calculated. The interneurons--in the LGN--have widespread contacts with both types of relay neurons, similarly the relay neurons contact the interneurons. The numerical data of morphological observations are accord with the results of physiologists.