Quantitative studies in the cerebral cortex of aging humans.

The capillary network of the human cerebral cortex was morphometrically investigated in a young, aged and aged hypertonic group. In the aging cortex, augmented values of capillary diameter and volume are accompanied by smaller distances between capillaries and an extended length per unit cortex volume. An increased capillary diameter of the aged hypertonic group is probably due to a high blood pressure. The regulating influence of the surrounding astroglia and the extracellular fluid on capillaries seems to lack. In comparison to normotonic brains, higher distances between capillaries and a decreased capillary length were measured.