This as-told-to essay is based on a conversation with Dr. Majid Fotuhi, a neurologist and adjunct professor at Johns Hopkins University, who researches neuroplasticity and prevention of Alzheimer's disease. He is also the author of "The Invincible Brain." The following has been edited for length and clarity. Neuroplasticity is your brain's ability to change and rewire itself at any age. Making new connections in your brain leads to physical anatomical changes in your brain. There's a part of