The Brain’s Frequencies
The marvels of human Experience and our states of consciousness can be measured, and so objectified by using the electroencephalograph (EEG)! Though incredibly complex, the human brain follows norms of activity that repeat throughout the entire organ. The electroencephalograph is able to read the electrical potentials that are liberated by the neurons (brain cells) while they send their electrical messages across the body of the cell. When a great number of neurons liberate electricity at the same frequency (speed) in a localized area, they generate and electrical potential sufficiently large to be read by the sensor which is placed on the scalp over that area.
The number of neurons using a certain frequency to pass their messages is what defines the amplitude (power) of what the EEG reads. When we look at a spectrum of all the frequencies that are read by the EEG, we can usually notice one frequency the has an amplitude which predomains over the other frequencies. Here we see the electrical speed that is guiding the consciousness of that person at that instant (highly simplified).
This short text will serve to demonstrate the five frequencies that are most recognized as "states of consciousness". Our understand of the link between a brain frequency and a perceptual state comes to us with a LOT of research supporting it. Since 1929, neurologists, psychiatrists, anatomists, electrical engineers, and millions of research subjects have worked together to create a basic understanding of "consciousness". Today this knowledge is already applied on the clinical level; with consistently replicable results. Thus it is worth the effort to learn and remember this little bit of basic theory before going further into study of different problematic brain-electrical patterns. This "map" of consciousness can help you decide where you want to guide yourself.
Frequencies are measured in Hertz (waves per second). Manually reading the raw wave-form information is simple, though slow. The computer is able to instantly translate the waves into more palpable forms (see the bargraph on the left of this image). This doesn’t free us professionals from the responsibility to, at least, be able to do a manual reading of the raw information which we receive. Let’s look from slowest to fastest.
Delta: 0-4 Hz
Note that each vertical line of this wave-form represents one second. Now, choosing the second second, count how many times the wave has passed through the midline. Each two times that a wave passes throug the mid-line equal one wave. In the second "epoch" (in this case, an "epoch" is one second long) we can count 4 waves, and so we have defined this epoch as predominantly Delta.
Delta predomains in the brain when a person is in profound sleep; with the consciousness completely internalizes. For the bodies cells, Delta serves as a regenerative state. If a person has a predominance of Delta while awake, he will have difficulties even telling us that he is very tired. This person will have a manner that appears disconnected from his surrounding society.
In biofeedback, it is extremely rare to train in increase in Delta (only for experiences with transcendental states). And it is also rare to train to reduce Delta. Instead, trainers can choose to train to reduce the activity of ALL the frequencies, including Delta.
Theta: 4-8Hz:
The Theta waveform looks very much like the Delta wave. Both have a sort of flat spot on their peak, both are large and wide. The difference we see here is that we can count 4 to 8 waves inside any one second of Theta. The image at left shows that the epoch has amplitudes predomaining at 6Hz, though it is easy to see that this image also has some Delta waves and also some Alpha. Rembember that it is the wave the exerts the greatest amplitude that is considered "Head"of that brain region at that time..
When Theta is "Head" of the consciousness, the person could be considered sleeping while awake; in trance, intuitive and internal. This person will have dificulty maintaining a conversation and looking in the other’s eyes at the same time, because the connection with another breaks that "center of the universal" feeling. Theta is a creative state that doesn’t keep a single point of focus. Thoughts in Theta are visual/emotional as opposed to linguistic/rational thought.
When a person generates only Theta it is generaly because of a lack of oxygen and also blood flow. With low levels of that life-giving liquid, the brain is forced to operate at slow speeds of function. These people can have problems with the pace of our society. They have dificulty maintaining one job because of the inadaquecies Theta has maintaining external attention. They certainly will have dificulties in situations like a classroom or a rigidly structured job-place.
However, it is important to look at the whole spectrum before deciding what is someone’s state of consciousness. For example, if a person generates a lot of Theta and at the same time relatively high levels of Beta or Alpha, the two speeds will be in balance with eachother, and the person’s personality will not necessarily be internal, perhaps a bit more "colorful".
Alpha: 8-12Hz
This wave has now sharpened itself. The Alpha waveform doesn’t have those flat tops and wide troughs. It is a smooth and thin wave- which oscillates from 8 to 12 times in a second. In the second, third, and fourth second of this image almost all the waves are at the Alpha frequency (minus an eyeblink and a couple of dips into Theta).
Alpha is the moment that a person has looked out from inside solely his or herself and looked to the world about. It is still not a very active state of consciousness. It is merely observing the surroundings. It’s in this state that we sense the beauty of the sea and we sing along to our favorite song. It is in Alpha that a person is able to listen during a conversation, without thinking of his or her own response. Simply listening.
When it is the all-time predominant frequency being generated, this person will have problems acting on ideas. He or she can have excellent ideas, but lack motivation. On the contrary, if a person is hardly able to generate Alpha (especially if the person strongly generates Beta at the same time) he or she can have problems with fatigue and anxiety which build up to more distructive diseases bred through the stress of constant vigilance.
The person will lost contact with the silence that recharges our patience and our mind so that we may be productive and in contact with our surroundings.
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