You may or may not be familiar with the practice of giving muscles a workout through electrostimulation. I understand it's done for people seriously bedridden for long periods to prevent muscle atrophy. It seems that now a similar effect can be achieved in the brain to the point that cognitive abilities can be restored to even overcome the effects of generous doses of Cocaine.
This could become a useful therapy depending on the long term benefits and/or side effects. One is reminded of Larry Niven's wireheads for whom electrostimulation of the pleasure centers of the brain is so addictive that they will starve rather than unplug.
This being a different effect, it could be a useful advantage to put on a stimulative headband before going to bed, and waking up more competitive in the morning. Either sort of thing has the potential for becoming a lucrative if illicit trade as long as the phrase "back-alley brain surgery" doesn't put you off.