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Updated: May 30, 2026
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Simultaneous fMRI and Electrophysiology in the Rodent Brain
Published on: August 19, 2010
How ongoing neuronal oscillations account for evoked fMRI variability.
Robert Becker1, Matthias Reinacher, Frank Freyer
1Bernstein Center for Computational Neuroscience Berlin and Bernstein Focus State Dependencies of Learning, Department of Neurology, Charité Universitaetsmedizin Berlin, Berlin, Germany. robert.becker@charite.de
Summary
Brain activity fluctuations, measured by electroencephalography (EEG) alpha rhythms, explain variations in functional magnetic resonance imaging (fMRI) responses to visual stimuli. This links brain rhythms to trial-by-trial processing variability.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Systems Neuroscience
Background:
- Variability in brain signals, like functional magnetic resonance imaging (fMRI), is observed even with consistent stimuli.
- Previous research suggested this variability impacts perception and behavior.
- The intrinsic neuronal sources of this fMRI signal variability remain unclear.
Purpose of the Study:
- To investigate if spontaneous neuronal oscillations, specifically the posterior alpha rhythm, account for the variability in evoked fMRI responses.
- To test the hypothesis of linear superposition between alpha rhythm fluctuations and visually evoked fMRI activity.
Main Methods:
- Simultaneous electroencephalography (EEG) and fMRI were used in human subjects.
- Real-time classification of ongoing alpha-rhythm states was performed.
- Visual stimulation was triggered based on these alpha-rhythm states.
Main Results:
- Spontaneous fluctuations in alpha-rhythm power significantly explained the variance in evoked fMRI responses across multiple brain regions, including extrastriate, thalamic, and cerebellar areas.
- The hypothesis of linear superposition was confirmed for extrastriate areas.
- This demonstrates a link between intrinsic brain rhythm power and evoked fMRI response variability.
Conclusions:
- Spontaneous fluctuations in the posterior alpha rhythm are a key source of trial-by-trial variability in evoked fMRI responses.
- This finding advances the understanding of how intrinsic brain rhythms influence stimulus processing and neural signal variability.
