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The electrochemical activity of the brain produces electromagnetic waveforms known as brainwaves. These waveforms can be objectively measured with sensitive equipment such as an electroencephalograph (EEG). As long as you are alive, these continuous electrical waves circulate throughout your brain. As with cessation of the heartbeat, the lack of brainwave activity is a sign of death.
Research into brain-wave states began in the 1920s and has continued to evolve through the use of biofeedback instruments. Researchers have divided the range of brainwave activity into four categories. Each state can be associated with different mental characteristics, and each has its own recognizable cycle. Therefore, knowing which brainwave state is most conducive to an activity—be it peak output (high beta) or fully relaxation (theta)—allows for optimal accomplishment of that activity.
The four major brainwave states are:
1. Beta waves (14 to 35 Hz). These are found in the normal, waking state of consciousness. You are alert, with a focus on the everyday activities of the world. Beta is also present during states of anxiety, tension, fear, and alarm.
2. Alpha waves (8 to14 Hz). These accompany states of relaxed wakefulness, such as daydreaming and meditation. They are blocked by sensory awareness, conceptual thinking, and strong emotions. Alpha waves generally appear in the occipital region of the brain (the visual cortex) when the eyes are closed.
3. Theta waves (4 to 8 Hz). These are found in near-unconscious states, very deep meditation, and as you drift into or out of sleep. This rhythm has been connected to states of reverie and hypnogogic states that produce dreamlike imagery. It is difficult to maintain this state without training in the disciplines of meditation.
4. Delta waves (0.5 to 4 Hz). Found in the deepest part of the sleep cycle and in unconsciousness, these are the longest and slowest waves.
At any given time, the brain is not functioning in just one level of brainwave activity; it is the combination of these brainwave states that determines the focus of our activities. According to Anna Wise, an internationally respected brainwave feedback expert, “Each state that you experience entails a symphony of brainwaves, with each frequency playing its own characteristic part. Out of these symphonies come the art of Picasso, the dance of Martha Graham, the architecture of Frank Lloyd Wright, and the theories of Einstein.” The interrelationship of brain-wave frequencies is what contributes to our various states of mental and subconscious awareness.
Brainwaves work in partnership with the heart rate and the breath rate, and all three body pulses are susceptible to the powerful effects of rhythmic entrainment.
"Brain Waves" is excerpted from The Power of Sound, published by Healing Arts Press.
(c) 2001 Joshua Leeds. All rights reserved.
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