The evaluation of cell-densities and of nerve-cell-size distribution by stereological procedures in a layered tissue (cortex cerebri).

The procedure of a stereological investigation of the cytoarchitectonics in the cerebral cortex is described. The number of all cells and--in order to obtain a size-distribution--the area of nerve-cells are measured with the help of an optomanual system (MOP-AM). The values and the distance of the evaluation-field from the cortical surface are transferred to a magnetic-tape. The principle of the arrangement of the fields has been described in Microscopica Acta, Vol. 71. The actual results including their statistics are calculated with a table-computer by using stereological formulas and by considering the magnification and the shrinkage of embedding. The measurement of the latter is also mentioned. The results can be printed in the form of various tables for lines, superlines, layers and the whole cortex and in the form of a newly developed computer-graph. The latter demonstrates the size-distribution of the nerve-cells and their dependence on the distance of the cortical surface. The task of our present study--the aging of the human cortex cerebri--is briefly given.