Beta wave

Beta waves

Beta wave, or beta rhythm, is a neural oscillation (brainwave) in the brain with a frequency range of between 12.5 and 30 Hz (12.5 to 30 cycles per second). Beta waves can be split into three sections: Low Beta Waves (12.5–16 Hz, "Beta 1 power"); Beta Waves (16.5–20 Hz, "Beta 2 power"); and High Beta Waves (20.5–28 Hz, "Beta 3 power").[1] Beta states are the states associated with normal waking consciousness.

History

Beta waves were discovered and named by the German psychiatrist Hans Berger, who invented electroencephalography (EEG) in 1924, as a method of recording electrical brain activity from the human scalp. Berger termed the larger amplitude, slower frequency waves that appeared over the posterior scalp when the subject's eye were closed alpha waves. The smaller amplitude, faster frequency waves that replaced alpha waves when the subject opened his or her eyes were then termed beta waves.[2]

Function

Low amplitude beta waves with multiple and varying frequencies are often associated with active, busy or anxious thinking and active concentration.[3]

Over the motor cortex beta waves are associated with the muscle contractions that happen in isotonic movements and are suppressed prior to and during movement changes.[4] Bursts of beta activity are associated with a strengthening of sensory feedback in static motor control and reduced when there is movement change.[5] Beta activity is increased when movement has to be resisted or voluntarily suppressed.[6] The artificial induction of increased beta waves over the motor cortex by a form of electrical stimulation called Transcranial alternating-current stimulation consistent with its link to isotonic contraction produces a slowing of motor movements.[7]

Relationship with GABA

Diffuse beta waves present alongside other frequencies in spontaneous EEG recorded from a 28-month-old child with Dup15q syndrome.

Beta waves are often considered indicative of inhibitory cortical transmission mediated by gamma aminobutyric acid (GABA), the principal inhibitory neurotransmitter of the mammalian nervous system. Benzodiazepines, drugs that modulate GABAA receptors, induce beta waves in EEG recordings from humans [8] and rats.[9] Spontaneous beta waves are also observed diffusely in scalp EEG recordings from children with duplication 15q11.2-q13.1 syndrome (Dup15q) who have duplications of GABAA receptor subunit genes GABRA5, GABRB3, and GABRG3.[10] For this reason, it is possible that, in certain clinical contexts, beta waves could be a general biomarker of GABAA receptor gene overexpression or otherwise aberrant GABAergic transmission.

Brainwaves

References

  1. ↑ Rangaswamy M, Porjesz B, Chorlian DB, Wang K, Jones KA, Bauer LO, Rohrbaugh J, O'Connor SJ, Kuperman S, Reich T, Begleiter (2002). "Beta power in the EEG of alcoholics". Biological Psychology. 52 (8): 831–842. doi:10.1016/s0006-3223(02)01362-8. PMID 12372655.
  2. ↑ Buzsáki, György (2006). Rhythms of the Brain. New York: Oxford University Press. p. 4.
  3. ↑ Baumeister J, Barthel T, Geiss KR, Weiss M (2008). "Influence of phosphatidylserine on cognitive performance and cortical activity after induced stress". NUTRITIONAL NEUROSCIENCE. 11 (3): 103–110. doi:10.1179/147683008X301478. PMID 18616866.
  4. ↑ Baker, SN (2007). "Oscillatory interactions between sensorimotor cortex and the periphery". Current Opinion in Neurobiology. 17 (6): 649–55. doi:10.1016/j.conb.2008.01.007. PMC 2428102. PMID 18339546.
  5. ↑ Lalo, E; Gilbertson, T; Doyle, L; Di Lazzaro, V; Cioni, B; Brown, P (2007). "Phasic increases in cortical beta activity are associated with alterations in sensory processing in the human". Experimental Brain Research. Experimentelle Hirnforschung. Experimentation cerebrale. 177 (1): 137–45. doi:10.1007/s00221-006-0655-8. PMID 16972074.
  6. ↑ Zhang, Y; Chen, Y; Bressler, SL; Ding, M (2008). "Response preparation and inhibition: the role of the cortical sensorimotor beta rhythm". Neuroscience. 156 (1): 238–46. doi:10.1016/j.neuroscience.2008.06.061. PMC 2684699. PMID 18674598.
  7. ↑ Pogosyan, A; Gaynor, LD; Eusebio, A; Brown, P (2009). "Boosting cortical activity at Beta-band frequencies slows movement in humans". Current Biology. 19 (19): 1637–41. doi:10.1016/j.cub.2009.07.074. PMC 2791174. PMID 19800236.
  8. ↑ Feshchenko, V; Veselis, R; Reinsel, R (1997). "Comparison of the EEG effects of midazolam, thiopental, and propofol: the role of underlying oscillatory systems". Neuropsychobiology. 35: 211–20. doi:10.1159/000119347. PMID 9246224.
  9. ↑ Van Lier, Hester; Drinkenburg, Wilhelmus; Van Eeten, Yvonne; Coenen, Anton (2004). "Effects of diazepam and zolpidem on EEG beta frequencies are behavior-specific in rats". Neuropharmacology. doi:10.1016/j.neuropharm.2004.03.017. Retrieved 4 January 2017.
  10. ↑ Frohlich, Joel; Senturk, Damla; Saravanapandian, Vidya; Golshani, Peyman; Reiter, Lawrence; Sankar, Raman; Thibert, Ronald; DiStefano, Charlotte; Huberty, Scott; Cook, Edwin; Jeste, Shafali (December 2016). "A Quantitative Electrophysiological Biomarker of Duplication 15q11.2-q13.1 Syndrome" (PDF). PLOS One. 11: e0167179. doi:10.1371/journal.pone.0167179. PMC 5157977. PMID 27977700. Retrieved 4 January 2017.
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