Amongst other great gifts for Christmas, my mother gave me a book entitled The Brain That Changes Itself, by Norman Doidge. In classic Jeff form, I procrastinated reading it until just recently. Once I got into it however, it became as engrossing as a Lee Child or Tom Clancy novel. It talks about neuroplasticity, which simply means that our brains can be changed positively with a little exercise. The book documents examples of people with Alzheimer's, strokes, brain injuries, and other ailments, and shows how what was once considered permanent brain damage can be reversed using the latest in neuroplastic advancements.
I'm only into the third chapter, but already, the information I've learned is incredible. The book explains why people become forgetful as they age, and the best ways to prevent this from happening. As the author explains, medical science has gotten very good at keeping people alive into their eighties using tools that make us more physically healthy. What's needed is a comparable amount of focus on mental health, so that everyone can fully enjoy this longevity.
There is a website one of the neuroplasticians founded called Posit Science, and you can try several exercises for free that help train your brain to become better.
It's a great book that explains complicated brain functions in a simple way, and every chapter is more interesting than the last. I HIGHLY recommend reading it. Don't procrastinate. :-)