What happens in the brain?
You probably know that your brain works by sending signals. Chemical messengers, called neurotransmitters, allow brain cells to communicate with each other. But a person with Alzheimer disease has decreased amounts of neurotransmitters. People with Alzheimer disease also develop deposits of stuff (protein and fiber) that prevent the cells from working properly. When this happens, the cells can't send the right signals to other parts of the brain. Over time, brain cells affected by Alzheimer disease also begin to shrink and die.