When I saw an Associated Press article this month promising brain improvement - "Study suggests old brains can be improved" - I got excited. Old brains can be improved? Like laundry detergent? I had to know more. Researchers discovered the key to young brain function, a neurochemical called GABA. GABA keeps young people's brains spry by suppressing "stray signals" that can "distract and overwhelm" your brain "in the same way the ear is overwhelmed when trying to hear a whisper at a rock concert." What I wonder is this: Is the whisper what is overwhelming your ear at a rock...