The number of nerve cells in the brain decreases. However, the brain can partly compensate for this loss in several ways:
As cells are lost, new connections are made between the remaining nerve cells.
New nerve cells form in some areas of the brain, even during old age.
The brain has more cells than it needs to do most activities—a characteristic called redundancy. ( there is more brain that is used).
Nerve cells lose some of their receptors for messages. Blood flow to the brain decreases. Because of these age-related changes, the brain functions slightly less. Older people react and do tasks more slowly, but given time, they do these things accurately. Some mental functions—such as vocabulary, short-term memory, the ability to learn new material, and the ability to recall words—are subtly reduced after age 70.
After about age 60, the number of cells in the spinal cord begins to decrease. Usually, this change does not affect strength or sensation. Nerves repair themselves more slowly and incompletely. But it is possible to stimulate the neural system (NEUREX) through the use of exercises, challenges, and electric stimulation. With the right stimulus, the loss of capacity can be compensated to a certain level.