Readers of this thread might be interested in reading _The High Performance Mind_ by Anna Wise. She discusses the various brainwave frequencies, and how to "activate" them. All of the brainwaves are present in varying proportions all the time - shifting into different "states" ius simply a matter of decreasing some and increasing others. A strong mixture of alpha and theta waves can be generated while lowering beta output through intense imagery exercises while keeping the body and conscious mind deeply relaxed.
