The brain is fascinating. It's capacity is amazing. I am not sure people understand a lot about what the brain does and how it functions. Knowing more about a 'normal' brain can help with understanding what goes wrong in a damaged brain, due to dementia. This brain tour from the Alzheimer's Association give a good, basic tutorial about the brain and how it is affected with dementia.
What faulty 'brain function' first concerned you with the person with dementia you know?