"Alpha waves are one type of brain waves detected either by electroencephalography (EEG) or magnetoencephalography (MEG) and predominantly originate from the occipital lobe during wakeful relaxation with closed eyes. Alpha waves are reduced with open eyes, drowsiness and sleep."
Alpha waves are present at different stages of the wake-sleep cycle. The most widely researched is during the relaxed mental state, where the subject is at rest with eyes closed, but is not tired or asleep. This alpha activity is centered in the occipital lobe, and is presumed to originate there, although there has been recent speculation that it instead has a thalamic origin. This wave begins appearing at around four months, and is initially a frequency of 4 waves per second. The mature alpha wave, at 10 waves per second, is firmly established by age 3."
"It is a handy analogy to think of Brainwaves as musical notes - the low frequency waves are like a deeply penetrating drum beat, while the higher frequency brainwaves are more like a subtle high pitched flute. Like a symphony, the higher and lower frequencies link and cohere with each other through harmonics. "
DELTA WAVES (.5 TO 3 HZ)
Delta brainwaves are slow, loud brainwaves (low frequency and deeply penetrating, like a drum beat). They are generated in deepest meditation and dreamless sleep. Delta waves suspend external awareness and are the source of empathy. Healing and regeneration are stimulated in this state, and that is why deep restorative sleep is so essential to the healing process.
THETA WAVES (3 TO 8 HZ)
Theta brainwaves occur most often in sleep but are also dominant in deep meditation. It acts as our gateway to learning and memory. In theta, our senses are withdrawn from the external world and focused on signals originating from within. It is that twilight state which we normally only experience fleetingly as we wake or drift off to sleep. In theta we are in a dream; vivid imagery, intuition and information beyond our normal conscious awareness. It?s where we hold our ?stuff?, our fears, troubled history, and nightmares.
ALPHA WAVES (8 TO 12 HZ)
Alpha brainwaves are dominant during quietly flowing thoughts, and in some meditative states. Alpha is ?the power of now?, being here, in the present. Alpha is the resting state for the brain. Alpha waves aid overall mental coordination, calmness, alertness, mind/body integration and learning.
BETA WAVES (12 TO 38 HZ)
Beta brainwaves dominate our normal waking state of consciousness when attention is directed towards cognitive tasks and the outside world. Beta is a ?fast? activity, present when we are alert, attentive, engaged in problem solving, judgment, decision making, and engaged in focused mental activity.
Beta brainwaves are further divided into three bands; Lo-Beta (Beta1, 12-15Hz) can be thought of as a 'fast idle, or musing. Beta (Beta2, 15-22Hz) is high engagement or actively figuring something out. Hi-Beta (Beta3, 22-38Hz) is highly complex thought, integrating new experiences, high anxiety, or excitement. Continual high frequency processing is not a very efficient way to run the brain, as it takes a tremendous amount of energy.
GAMMA WAVES (38 TO 42 HZ)
Gamma brainwaves are the fastest of brain waves (high frequency, like a flute), and relate to simultaneous processing of information from different brain areas. It passes information rapidly, and as the most subtle of the brainwave frequencies, the mind has to be quiet to access it. Gamma was dismissed as 'spare brain noise' until researchers discovered it was highly active when in states of universal love, altruism, and the ?higher virtues?. Gamma is also above the frequency of neuronal firing, so how it is generated remains a mystery. It is speculated that Gamma rhythms modulate perception and consciousness, and that a greater presence of Gamma relates to expanded consciousness and spiritual emergence.