Alpha wave


Alpha wave

Alpha waves are electromagnetic oscillations in the frequency range of 8–12 Hz arising from "synchronous" and "coherent" ("in phase" / "constructive") electrical activity of thalamic pacemaker cells in the human brain. They are also called Berger's wave in memory of the founder of EEG Harv|Brazier|1970.

"Alpha waves" are one type of brain waves, commonly detected by electroencephalography (EEG) or magnetoencephalography (MEG) and predominantly found to originate from the occipital lobe during periods of waking relaxation with the eyes closed. Conversely alpha waves are attenuated with open eyes as well as by drowsiness and sleep. They are thought to represent the activity of the visual cortex in an idle state. Occipital alpha waves during periods of eyes closed are the strongest brain signals of the EEG. They usually can be detected with the naked eye.

An alpha-like normal variant called mu (μ) is sometimes seen over the motor cortex (central scalp) and attenuates with movement, or even with the intention to move.

References

*

ee also

* Electroencephalography
* SMR (Sensory Motor Rhythm)
* Sensory Integration Dysfunction
* Holonomic brain theory
* Epilepsy
* Sleep
* Mu wave
* Beta wave
* Delta wave
* Gamma wave
* Theta wave
* Theanine


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • alpha wave — n. any of the electrical waves from the parietal and occipital regions of the brain, having frequencies from 8 to 13 hertz: a sign of relaxation, since they indicate a lack of sensory stimulation in a conscious person: also alpha rhythm * * * …   Universalium

  • alpha wave — n an electrical rhythm of the brain with a frequency of 8 to 13 cycles per second that is often associated with a state of wakeful relaxation called also alpha …   Medical dictionary

  • alpha wave — n. any of the electrical waves from the parietal and occipital regions of the brain, having frequencies from 8 to 13 hertz: a sign of relaxation, since they indicate a lack of sensory stimulation in a conscious person: also alpha rhythm …   English World dictionary

  • alpha wave — noun the normal brainwave in the electroencephalogram of a person who is awake but relaxed; occurs with a frequency of 8 12 hertz • Syn: ↑alpha rhythm • Hypernyms: ↑brainwave, ↑brain wave, ↑cortical potential * * * noun or …   Useful english dictionary

  • alpha wave — {n.} A brain wave, 8 12 cycles per second, associated with a state of relaxation and meditation and, hence, free of anxieties. * /Try to produce some alpha waves; you will instantly feel a lot better./ …   Dictionary of American idioms

  • alpha wave — {n.} A brain wave, 8 12 cycles per second, associated with a state of relaxation and meditation and, hence, free of anxieties. * /Try to produce some alpha waves; you will instantly feel a lot better./ …   Dictionary of American idioms

  • alpha\ wave — noun A brain wave, 8 12 cycles per second, associated with a state of relaxation and meditation and, hence, free of anxieties. Try to produce some alpha waves; you will instantly feel a lot better …   Словарь американских идиом

  • alpha wave — /ˈælfə weɪv/ (say alfuh wayv) noun a periodic variation in the electrical potential of the normal cerebral cortex with a frequency about 8 to 12 hertz in the resting state. Compare beta wave. Also, alpha rhythm …   Australian English dictionary

  • alpha wave — noun Date: 1936 an electrical rhythm of the brain with a frequency of approximately 8 to 13 cycles per second that is often associated with a state of wakeful relaxation called also alpha, alpha rhythm …   New Collegiate Dictionary

  • alpha wave — noun An electrical signal produced by the brain while the subject is relaxed …   Wiktionary