We must be learning if we are to feel fully alive, and when life, or love, becomes too predictable and it seems like there is little left to learn, we become restless - a protest, perhaps, of the plastic brain when it can no longer perform its essential task.

If you want to lift a hundred pounds, you don't expect to succeed the first time. You start with a lighter weight and work up little by little. You actually fail to life a hundred pounds, every day, until the day you succeed. But it is in the days when you are exerting yourself that the growth is occurring.

Language development, for instance, has a critical period that begins in infancy and ends between eight years and puberty. After this critical period closes, a person’s ability to learn a second language without an accent is limited. In fact, second languages learned after the critical period are not processed in the same part of the brain as is the native tongue.

Ironically, some of our most stubborn habits and disorders are products of our plasticity.

Analysis helps patients put their unconscious procedural memories and actions into words and into context, so they can better understand them. In the process they plastically retranscribe these procedural memories, so that they become conscious explicit memories, sometimes for the first time, and patients no longer need to "relive" or "reenact" them, especially if they were traumatic.

All of us have worries. We worry because we are intelligent beings. Intelligence predicts, that is its essence; the same intelligence that allows us to plan, hope, imagine, and hypothesize also allows us to worry and anticipate negative outcomes.

Nothing speeds brain atrophy more than being immobilized in the same environment.