How aging affects the brain
Specific changes vary greatly from one person to the next, and may include the following, depending on their medical and psychological history:
Chemical messengers decrease
Brain mass shrinks: Beginning in our 60s or 70s, some people's overall brain mass may shrink a bit. Certain brain areas shrink more than others, including the frontal lobe (important for mental abilities) and the hippocampus (where new memories are formed).
Outer surface thins: The cortex—the heavily ridged outer surface of the brain—thins slightly with age. This thinning is not, as scientists once believed, the result of widespread loss of brain cells. Instead, the thinning of the brain's outer surface is likely due to a decrease in synaptic connections (a process that starts when we're about 20 years old). Synapses are like intersections. They allow brain cells to communicate with one another and to form connections.
White matter decreases: Many studies have linked aging with decreases in the brain's white matter (so called because it's made up, in part, of myelin—a fatty, white substance). Myelin helps to improve communication between brain cells.
Research shows that changes in white matter are linked with changes in speed of cognitive processing. Cognitive processing includes memory, attention, action, problem solving, and decision-making abilities
Chemical messengers decrease: As our brains age, they generate fewer neurotransmitters (chemicals like serotonin, which carry messages between brain cells), and have fewer receptors that lock onto these messengers. This change may have an effect on memory.
http://www.aarp.org/health/brain/aging/how_aging_changes_the_brai.html
I only posted the parts that talk about the affects of aging on the brain. I did not post the whole AARP article and you can go to the website and read the whole thing.
Aging has an affect on our brains. Towards the end of Reagan's second term he was beginning to have problems, luckily for us nothing drastic occured that would have required his removal.