Gamma waves - 30 - 70 Hz
Helps in processing various stimuli (visual, auditory, touch) into a coherent whole.
- - Gamma waves do not generally describe a state of conciousness but instead, play a supporting role in the brain. They are predominantly present while awake and are always supported by the other four waves in the beta, alpha, theta, or delta ranges.
- Gamma waves have been noted during Buddhist meditation of compassion & music listening experiments.
Beta waves - 13 to 30 Hz
Associated with general and selelective attention, concentration & anticipation. These waves are typically associated with concentrated mental activity such as solving math problems, anxiety, and apprehension.
- - Beta waves occur when the brain is working on goal-oriented tasks, such as planning a date or reflecting actively over a particular issue.
Alpha waves - 7 to 13 Hz
Associated with relaxed wakefulness, and creative thought where attention may wander and free association is favored. They are also correlated with a general tranquility, pleasant or almost floating feeling.
- - Considered as the brainwaves of meditation. Most prominent during meditation.
- Considered as an integral part of the relaxation process before sleep. The alpha frequency band has been studied extensively in various types of meditations and in almost all cases an increase in the alpha waves has been noted during meditation.
- Use of Cannabis (marijuana) has also been linked to an increase in alpha waves in brain.
Theta waves - 4 to 7 Hz
Associated with dreams, deep meditation, sleep and hypnosis. Seemed to be involved with short-term memory. It is a state of somnolence with reduced consciousness. The theta-state is described by sleep researchers as stage 1 sleep or the twilight state. In this state subjects pass out of the alert alpha-state into a theta-state in which they maintain the sense of still being awake but lose the sense of lying in bed.
- - Easily awoken from this stage of sleep, and has many interesting properties. For a brief time, as we lie in bed at night, we are neither fully awake nor yet asleep. We pass through a twilight mental zone like a state of reverie. Many people associate this drowsy stage with hallucinatory images, more fleeting and disjointed than dreams,. A host of artists and scientists have credited the imagery of this twilight state with creative solutions and inspiration for their work.
- This theta stage is also observed in people under hypnosis.
Delta waves - 1 to 4 Hz
Associated with deep dreamless sleep. Consistently observed in deep sleep. The deeper the sleep, the higher is the amount of delta waves.
- - Meditative states associated with the increased presence of delta waves seem to occur mostly in very experienced practitioners, possibly because entering a delta state and maintaining consciousness at the same time is tremendously difficult.
- Also related to the state of Samadhi, the deepest state in meditation as appeared in ancient Indian Yoga text.
Meditation and Binaural Beats
Meditation lowers the brainwave levels to an alpha state of consciousness, through relaxation of the brain. And, as the meditation deepens, the brainwave levels progress to theta and finally to delta state.
Research has found that an external stimulus, such as sound, can assist the brain in reaching an alpha or theta level and as a result achieve a meditative state. Binaural Beats is a field of study that has had excellent results in attaining meditative staes. Binaural beats were originally discovered in 1839 by physicist Heinrich Wilhelm Dove. He discovered when signals of two different frequencies are presented separately, one to each ear, your brain creates its own third signal — called a binaural beat — which is equal to the difference between those two frequencies. So, if a frequency of 100 Hz is presented to your left ear, and a frequency of 105 Hz is presented to your right ear, your brain interpolates a third frequency pulsing at 5 Hz, the exact difference between the two frequencies.
Research has proven that introducing a binaural beat will cause the brain to begin resonating in tune with that beat. By creating a binaural beat at 10 Hz — an Alpha frequency — you can trigger your brain to resonate at that same 10 Hz frequency, automatically inducing brain activity in the Alpha range. This same technique can be used to quickly and easily guide your mind into any state.