Research › QEEG, Methods & Mechanisms
Very Slow EEG Fluctuations Predict the Dynamics of Stimulus Detection and Oscillation Amplitudes in Humans
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Study at a glance
- Area
- QEEG, Methods & Mechanisms
- Study type
- Observational study
- Authors
- Monto S, Palva S, Voipio J, Palva JM
- Journal
- The Journal of Neuroscience
- Year
- 2008
- Protocol
- full-band EEG during a somatosensory detection task
Key findings
- Prominent 0.01-0.1 Hz fluctuations appeared in full-band EEG during the detection task
- Stimulus detection correlated strongly with the phase, but not the amplitude, of infraslow EEG fluctuations
- Amplitudes of 1-40 Hz oscillations in six frequency bands were robustly correlated with infraslow phase
- Infraslow fluctuations are proposed to reflect the excitability dynamics of cortical networks
Using full-band EEG, researchers examined very slow (infraslow, 0.01 to 0.1 Hz) fluctuations in brain activity while people performed a somatosensory detection task, to explain why the ability to detect weak stimuli rises and falls in streaks over time. Detection performance showed similar slow fluctuations and tracked the phase, not the amplitude, of the infraslow EEG. The amplitude of faster oscillations was also tied to that phase. The authors conclude infraslow fluctuations reflect cortical excitability and are functionally significant during cognitive tasks.