Electroencephalograph wave forms

From TinWiki.org

Electroencephalography (EEG) is the measurement of electrical activity produced by the brain as recorded from electrodes placed on the scalp.

Just as the activity in a computer can be perceived on multiple different levels, from the activity of individual transistors to the function of applications, so can the electrical activity of the brain be described on relatively small to relatively large scales. At one end are action potentials in a single axon or currents within a single dendrite, and at the other end is the activity measured by the scalp EEG.

1 Wave Form Activity
- 1.1 Comparison table
2 Alpha Waves and the Television
3 Theta Waves and Meditation
4 ATS Discussion Threads
5 External Source

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Wave Form Activity

The human brain oscillates on different frequences which correspond to different states of mind. When you are in a deep sleep, your brain is vibrating at anywhere from 1 to 3 Hz. When you are active, busy, anxious, or actively concentrating, your brain oscillates at anywhere from 12 to 30 Hz.

Here is a diagram from wikipedia which illustrates the different wave form attributes

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Comparison table

Comparison of EEG bands
Type	Frequency (Hz)	Location	Normally	Pathologically
Delta	up to 3	frontally in adults, posteriorly in children; high amplitude waves	adults slow wave sleep in babies	subcortical lesions diffuse lesions metabolic encephalopathy hydrocephalus deep midline lesions.
Theta	4 - 7 Hz		young children drowsiness or arousal in older children and adults	focal subcortical lesions metabolic encephalopathy deep midline disorders some instances of hydrocephalus
Alpha	8 - 12 Hz	posterior regions of head, both sides, higher in amplitude on dominant side. Central sites (c3-c4) at rest .	closing the eyes and by relaxation.	coma
Beta	12 - 30 Hz	both sides, symmetrical distribution, most evident frontally; low amplitude waves	active, busy or anxious thinking, active concentration	benzodiazepines
Gamma	26–100		certain cognitive or motor functions

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Alpha Waves and the Television

According to psychophysiologist [Thomas Mulholland][1] and his research, the brain starts emitting alpha waves after 30 seconds of watching the television. Alpha brain waves are associated with unfocused, overly receptive states of consciousness. A high frequency alpha waves does not occur normally when the eyes are open. In fact, Mulholland’s research implies that watching television is neurologically analogous to staring at a blank wall.

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Theta Waves and Meditation

It has been said that theta waves are elusive in nature. Most people only experience the theta wave state (4-7 Hz) right before they go to sleep and right before they wake up. Meditation, after continued practice, allows a person to consciously enter the theta wave state at will and allows a development of self mind control.

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