Research has shown that as brain ages or as people get older, there will be a decrease in brain weight and brain volume, widening of the grooves on the surface of the brain and enlargement of the ventricular system (ventricles- a cavity or hollow part of the brain).

The decrease in brain weight and brain volume are probably due to loss of neurons (specialized cells transmitting nerve impulses) and extra cellular fluid. Man may have a 20% reduction in brain weight between the ages of forty -five and eighty -five and lose thirty to fifty thousand neurons a day from the brain and nervous system as they age. Enlargement of the ventricular system may be probably due to loss of cells surrounding the ventricles (the spaces in the brain that contain cerebrospinal fluid).