Article

New vistas for Alpha-frequency band oscillations

Neuroscience Center, University of Helsinki P.O. Box 56, FI-00014 University of Helsinki, Finland.
Trends in Neurosciences (Impact Factor: 12.9). 05/2007; 30(4):150-8. DOI: 10.1016/j.tins.2007.02.001
Source: PubMed

ABSTRACT The amplitude of alpha-frequency band (8-14 Hz) activity in the human electroencephalogram is suppressed by eye opening, visual stimuli and visual scanning, whereas it is enhanced during internal tasks, such as mental calculation and working memory. alpha-Frequency band oscillations have hence been thought to reflect idling or inhibition of task-irrelevant cortical areas. However, recent data on alpha-amplitude and, in particular, alpha-phase dynamics posit a direct and active role for alpha-frequency band rhythmicity in the mechanisms of attention and consciousness. We propose that simultaneous alpha-, beta- (14-30 Hz) and gamma- (30-70 Hz) frequency band oscillations are required for unified cognitive operations, and hypothesize that cross-frequency phase synchrony between alpha, beta and gamma oscillations coordinates the selection and maintenance of neuronal object representations during working memory, perception and consciousness.

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Available from: Satu Palva, Aug 27, 2015
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    • "2013 ) . While variations in the posterior alpha band have been extensively studied , the underlying neural mechanisms remain controversial ( for review see Palva & Palva , 2007 ; Thut & Miniussi , 2009 ; Klimesch , 2012 ) . We have recently demonstrated , by means of magnetic resonance spectroscopy , that GABA concentration decreased after transient mono - cular deprivation in the primary visual cortex of adult humans ( Lunghi et al . "
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    • "An experimental scenario was created where native Spanish speakers who were relatively proficient in English (i.e., foreign language) but had no knowledge of French (i.e., unknown language) completed a visual go/no-go task while different audio tracks including everyday conversations were being played in the background (a manipulation that was completely orthogonal to the main visual discrimination task). Because amplitude (power) and phase synchronization can reflect different neural processes (i.e., Palva & Palva, 2007), both were investigated here. Spectral power reflects local activations of large groups of neurons (Singer, 1999), indexing the resonance of the brain activity to the rhythms of speech (Buiatti, Peña, & Dehaene-Lambertz, 2009). "
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