Gamma wave

A gamma wave is a pattern of brain waves, associated with perception and consciousness. Gamma waves are produced when masses of neurons emit electrical signals at the rate of around 40 times a second (40 hertz or Hz), but can often be between 26 and upwards of 70 Hz. By one definition, gamma waves are manifest at 24 Hz and higher, though researchers have recognized that higher level cognitive activities occur when lower frequency gamma waves suddenly double into the 40 Hz range. Research has shown gamma waves are continuously present during low voltage fast neocortical activity (LVFA), which occurs during the process of awakening and during active rapid eye movement (REM) sleep. Some researchers do not distinguish gamma waves as a distinct class but include them in beta brain waves.

Linked to higher reasoning faculties

Gamma waves are involved in higher mental activity. Transient periods of synchronized firing over the gamma waveband, of entire banks of neurons from different parts of the brain, have been proposed as a mechanism for bringing a distributed matrix of cognitive processes together to generate a coherent, concerted cognitive act, such as perception. For example, it has been suggested that gamma waves are associated with solving the binding problem. Recent studies have shown that recognition of new insights occur when patterns jump from 20 to 40 Hz.Fact|date=September 2007

Consciousness

Gamma waves have been studied in how visual cues elicit a neural synchronic reaction with both conscious and subliminal stimuli. [ [http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=17285879&ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum] Ward LM, Doesburg SM, Kitajo K, MacLean SE, Roggeveen AB. "Neural synchrony in stochastic resonance, attention, and consciousness." Can J Exp Psychol. 2006 Dec;60(4):319-26.] This research also sheds light on how neural synchrony may explain stochastic resonance in the nervous system. [ Lucia Melloni, Carlos Molina, Marcela Pena, David Torres, Wolf Singer and Eugenio Rodriguez. [http://www.jneurosci.org/cgi/pmidlookup?view=long&pmid=17360907 Final proof of role of neural coherence in consciousness?] The Journal of Neuroscience, March 14, 2007, 27(11):2858-2865; doi:10.1523/JNEUROSCI.4623-06.2007.]

Risk of false detection

There are studies showing that EEG-measured gamma waves could be in many cases an artifact of electromyographic activity cite journal |author=Whitham EM, Pope KJ, Fitzgibbon SP, "et al" |title=Scalp electrical recording during paralysis: quantitative evidence that EEG frequencies above 20 Hz are contaminated by EMG |journal=Clin Neurophysiol |volume=118 |issue=8 |pages=1877–88 |year=2007 |month=August |pmid=17574912 |doi=10.1016/j.clinph.2007.04.027 |url=http://linkinghub.elsevier.com/retrieve/pii/S1388-2457(07)00198-8] and miniature eye movements. cite journal |author=Yuval-Greenberg S, Tomer O, Keren AS, Nelken I, Deouell LY |title=Transient induced gamma-band response in EEG as a manifestation of miniature saccades |journal=Neuron |volume=58 |issue=3 |pages=429–41 |year=2008 |month=May |pmid=18466752 |doi=10.1016/j.neuron.2008.03.027 |url=http://linkinghub.elsevier.com/retrieve/pii/S0896-6273(08)00301-2] cite journal |author=Whitham EM, Lewis T, Pope KJ, "et al" |title=Thinking activates EMG in scalp electrical recordings |journal=Clin Neurophysiol |volume=119 |issue=5 |pages=1166–75 |year=2008 |month=May |pmid=18329954 |doi=10.1016/j.clinph.2008.01.024 |url=http://linkinghub.elsevier.com/retrieve/pii/S1388-2457(08)00045-X] Therefore, careful signal separation is necessary to discern them from real brain gamma-activity.

ee also

* Electroencephalography
* SMR
* Sensory Integration Dysfunction
* Holonomic brain theory
* Epilepsy
* Sleep
* Mu wave
* Alpha wave
* Beta wave
* Delta wave
* Theta wave

External links

* [http://www.epilepsyhealth.com/biofeedback.html EpilepsyHealth.com] - 'A Sampling from Chapter 3' "Biofeedback, Neurofeedback and Epilepsy", Sally Fletcher (2005)
* [http://www.nature.com/news/1999/990211/pf/990211-2_pf.html Nature.com] - 'Thinking in Synchrony', Henry Gee (February, 1999)

References

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Further reading

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* https://www.dalailama.com/news.112.htm