Scientific American reports that meditating Zen monks have an ability to bring the waves from disparate brain regions into "near lockstep, like numerous jump ropes turning precisely together," which is known as gamma synchrony-- "a pattern increasingly associated with robust brain function and the synthesis of activity that we call the mind. "
Such results connote more than spiritual harmony; they reflect the coordination of otherwise scattered groups of neurons. Gamma synchrony increases as a person concentrates or prepares to move. And lack of synchrony indicates discordant mental activity such as schizophrenia. Finally, a growing body of theory proposes that gamma synchrony helps to bind the brain's many sensory and cognitive operations into the miracle of consciousness.Read the report here: Zen Gamma
That hypothesis certainly agrees with the monks' gamma readings, seemingly confirming that Zen meditation produces not relaxation but an intense though serene attention.