The aging of cortical cytoarchitectonics in the light of stereological investigations.

With the help of stereological procedures quantitative results concerning the aging of the human cortex could be found. 1. Older brains shrink less during the histological treatment than younger ones. 2. The neuronal density does not change in all four estimated areas (Brodman 6, 7, 11, 17). 3. In two areas (frontal lobe) a statistical significant decrease of neuronal cell size could be found. The conclusion allows the statement that the various parts of cortex age differently.