That slight mental discomfort is often the sign that the brain is actually being trained, a lot like that good workout burn in your muscles. As a neurologist who studies brain activity, I use electroencephalograms, or EEGs, to record the brain’s electrical patterns. The crucial importance of restAmong all forms of rest, sleep is the most powerful. During REM sleep, the stage of sleep linked to dreaming, the brain replays patterns from the day to consolidate memories. You can start now, with choices that tell your brain that growth is still the plan.