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{{Dablink|For the 3D platform video game, see [[Alpha Waves]].}}

[[Image:eeg alpha.svg|thumb|Alpha waves |400px|right]]
'''Alpha waves''' are [[Electromagnetic radiation|electromagnetic]] [[neural oscillations|oscillations]] in the frequency range of 8–12 [[Hertz|Hz]] arising from ''[[Neural synchronization|synchronous]]'' and ''coherent'' (''in phase'' / ''constructive'') electrical activity of [[Human thalamus|thalamic]] pacemaker cells in humans. They are also called [[Hans Berger|Berger]]'s wave in memory of the founder of EEG.

''Alpha waves'' are one type of [[Neural oscillations|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. Historically, they were thought to represent the activity of the visual cortex in an idle state.  More recent papers have argued that they inhibit areas of the cortex not in use, or alternatively that they play an active role in network coordination and communication.<ref>Palva, S. and Palva, J.M., New vistas for a-frequency band oscillations, Trends Neurosci. (2007), doi:10.1016/j.tins.2007.02.001</ref> Occipital alpha waves during periods of eyes closed are the strongest EEG brain signals. They usually can be detected with the naked eye.{{cCitation needed|date=January 2011}}

An alpha-like variant called [[Mu rhythm|mu (μ)]] can be found over the motor cortex (central scalp) that is reduced with movement, or the intention to move. Alpha waves do not start to appear until three years of age.<ref>Kolev V, Başar-Eroglu C, Aksu F, Başar E. (1994). EEG rhythmicities evoked by visual stimuli in three-year-old children.
Int J Neurosci. 75(3-4):257-70. PMID 8050866</ref>

==History of alpha waves==

Alpha waves were discovered by German [[Neurologist|neurologist]] [[Hans Berger|Hans Berger]], most famous for his invention of the EEG. Alpha waves were among the first waves documented by Berger, along with beta waves, and he displayed an interest in “alpha blockage”, the process by which alpha waves decrease and beta waves increase upon a subject opening their eyes. This distinction earned the alpha wave the alternate title of “Berger’s Wave”.  

Berger took a cue from Eastern European physiologist [[Vladimir Pravdich-Neminsky|Pravdich-Neminski]], who used a [[string galvanometer|string galvanometer]] to create a photograph of the electrical activity of a dog's brain. Using similar techniques, Berger confirmed the existence of electrical activity in the human brain. He first did this by presenting a stimulus to hospital patients with skull damage and measuring the electrical activity in their brains. Later he ceased the stimulus method and be(contracted; show full)L. S., et. al(2009). Tobacco smoking produces widespread dominant brainwave alpha frequency increases. International Journal of Psychophysiology. 74(3):192-198.</ref> 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. <ref>Niedermeyer E.(1997). Alpha rhythms as physiological and abnormal phenomena. International Journal of Psychophysiology. 26(1-3):31-49.</ref>
    

The second occurrence of alpha wave activity is during REM sleep. As opposed to the awake form of alpha activity, this form is located in a frontal-central location in the brain. The purpose of alpha activity during REM sleep has yet to be fully understood. Currently, there are arguments that alpha patterns are a normal part of REM sleep, and for the notion that it indicates a semi-arousal period. It has been suggested that this alpha activity is inversely related to REM sleep pressure.  

The third occurrence of alpha wave activity is the alpha-delta or slow-wave (SWS) state. This activity spreads across the brain in an anterior-posterior gradient. <ref>Pivik R. T., Harman K. (1995). A Reconceptualization of EEG alpha activity as an index of arousal during sleep: all alpha activity is not equal.
Journal of Sleep Research. 4(3):131-137.</ref>

It has long been believed that alpha waves indicate a wakeful period during sleep. This has been attributed to studies where subjects report non-refreshing sleep and have EEG records reporting high levels of alpha intrusion into sleep. This occurrence is known as alpha wave intrusion. <ref>Allas Task Force (1992). ASDA report on EEG arousals: scoring rules and examples. Sleep. 15(2):173-184.</ref> However, it is possible that these explanations may be misleading, as they only focus on alpha waves being generated from the occipital lobe.  

==Alpha wave intrusion==

Alpha wave intrusion occurs when alpha waves appear with non-REM sleep when delta activity is expected.  It is hypothesized to be associated with [[fibromyalgia]]<ref>{{cite journal |author=Germanowicz D, Lumertz MS, Martinez D, Margarites AF |title=Sleep disordered breathing concomitant with fibromyalgia syndrome |journal=J Bras Pneumol |volume=32 |issue=4 |pages=333–8 |year=2006 |pmid=17268733 |doi= |url=}}</ref>, although the study may be inadequate due to a small (contracted; show full)

There are several different prospects of this training that are currently being explored. Arguably, the most popular one is the use of this training in [[meditation|meditation]]. Zen-trained meditation masters produce noticeably more alpha waves during meditation. This fact has led to a popular fad of biofeedback training programs for everyday stress relief. Most of these have little psychological basis, and are used as fads or scams.
  

This is not to be confused with the real potential for biofeedback in therapeutic sessions. Psychologists are hoping to use this technique to help people overcome [[phobia|phobias]], calm down [[hyperactivity|hyperactive]] children, and help children with [[stuttering|stuttering]] problems to relax enough to practice regular speech.

One psychologist, Elmer Green, is attempting to train patients to lower their alpha waves, as he believes that, in a low-alpha, high-theta brain state, it is easier to access unconscious problems.
Similar to this relaxed-state thinking, some major companies, such as Martin Marietta and Xerox, are hoping to facilitate creative thinking in their employees through biofeedback use.  

There are other uses of biofeedback training beyond therapy. Defense Department researchers are exploring biofeedback as a way of getting captured soldiers to create alpha waves, potentially messing up enemy lie detectors. And biofeedback training has been receiving attention as a way of monitoring attention. It has been theorized that teaching machines could use biofeedback as a way of monitoring childrens' attention, with the appearance of alpha waves signaling a lapse of attention. <ref> Tim(contracted; show full)
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