The fact that our brains are electrical is a relatively new discovery.
The first article about electrical phenomena in the brains of monkeys and rabbits was published in the British Medical Journal of 1875.
Nearly a half century would pass before the first human EEG (electroencephalogram) was recorded. That distinction would go to German psychiatrist and physiologist Hans Berger who invented the device that would begin the field of electroencephalography.
The 4 Building Blocks of Consciousness
There are 4 basic brain wave frequencies and each correlates with a specific state of consciousness. Like sound frequencies, brain waves are measured in Hz, or cycles per second. In general, the slower the frequency of your brain waves, the more relaxed you feel.
Meditation, neurofeedback, hypnosis, and guided imagery have all been shown to help people control their brain waves more efficiently for better health, higher performance, and a more positive experience of life.
Beta Waves: 13-30 Hz
Your brain is producing beta waves as you are reading this. A predominance of beta waves is associated with being alert, active, and whenever you concentrate on learning something or doing an activity that requires focus.
Beta waves are also associated with over-thinking and worry. While the beta state has gotten a bad rap in some meditation circles, you need your brain to generate beta waves in order to think and function consciously.
But when you want to relax, it’s time to shift into alpha.
Alpha Waves: 8-13 Hz
Alpha is the brain wave associated with relaxed, daydreaming states of mind; it’s a state of relaxed, detached awareness. Many people are “in alpha” while watching TV. Alpha is often called a “hypnogogic” state because you may experience spontaneous mental imagery.
If you’re like most people, when you close your eyes and take a few slow, deep breaths you’ll experience a light, relaxed alpha state. Alpha is considered the gateway to meditation. Some people consider alpha waves to be the link between the conscious mind and the subconscious.
You produce alpha waves when you relax to guided imagery. Your brain also produces alpha waves just before you drift off to sleep and just before you wake up. At the beginning of “stage 1 sleep” alpha waves disappear and theta waves appear.
Theta: 4-8 Hz
Theta waves are often associated with deep states of meditation, peak spiritual experiences, and higher states of consciousness. Theta waves are associated with drowsiness or arousal in adults and older children. Young children are in theta most of the time.
Some people consider the theta state to be synonymous with the subconscious mind wherein reside suppressed emotions, as well as a storehouse of creativity. Theta is associated with REM (rapid eye movement) sleep where dreams occur.
Delta: up to 4 Hz
Delta waves occur in adults during deep, or “slow wave” sleep. It seems this state is needed by the brain because after a period of sleep deprivation, there’s usually a rebound of slow wave sleep. Alcohol interferes with delta wave sleep. A low carbohydrate diet has been shown to increase the amount of delta activity and deep sleep in healthy individuals.
Delta states sometimes occur during continuous attention tasks.
Delta is considered by some to be the bridge to what Carl Jung described as the “collective unconscious.” Babies are in delta much of the time. For some reason adult females have been shown to have more delta wave activity. This is true not just in humans but in most mammals.
Beyond the Basic Brain Waves
Gamma: 25-100 Hz
Neurologists have also described a Gamma brainwave that’s thought to be involved with our sense of conscious awareness. Gamma waves range in frequency from 25 to 100 Hz though usually they are around 40 Hz. Studies of Tibetan Buddhist monks have shown a correlation between gamma waves and transcendental states of consciousness, but not all neuroscientists are convinced.
Mu 8-13 Hz
The Mu wave is a brain frequency which has been observed and studied since the 1930′s. Mu waves are in the range of 8-13 Hz and arise from large groups of neurons in the brain.
Recently Mu brain waves have been associated with the “mirror neuron” system that activates when we watch another person’s activity. Because mu brain waves may play a role in our ability to understand and imitate others’ behavior, enhancing mu wave activity via neurofeedback is being studied as a therapy for autism. Early results are promising.