Transcript

You've had most of the neurons in your brain since birth, and most of those will stick around for the rest of your life, yet your brain is constantly changing. Learn a new skill or language, and your brain reacts by strengthening or weakening the connections between neurons, even creating new ones. Each new experience shapes your brain to become uniquely yours, and your brain's capacity to change is vital.

A brain damaged by injury or disease attempts to regain lost abilities, rerouting connections and sometimes even growing new neurons, but quite slowly still, a healthy brain needs neurons to die off too. During development, the human brain grows excess neurons early in life, the brain eliminates those extra cells to keep only those connections you need. Later on, unused neurons can wither away. Physical and mental exercise preserves them, keeping your brain healthy.