Localizing movement-related primary sensorimotor cortices with multi-band EEG frequency changes and functional MRI

Area of Science:

• Neuroscience
• Cognitive Science
• Biomedical Engineering

Background:

• Cerebral cortex activity generates electroencephalographic (EEG) oscillations across multiple frequency bands.
• A key question is whether focal cortical activity, like during finger movements, corresponds to localized EEG changes.
• Previous research has compared EEG to functional MRI (fMRI) but not localized multiple EEG frequency changes with fMRI data during motor tasks.

Purpose of the Study:

• To investigate if focal EEG oscillatory changes during motor tasks align with fMRI-localized hemodynamic activity.
• To compare the spatial localization of multiple EEG frequency bands with fMRI data in the same individuals during motor tasks.

Main Methods:

• Five participants performed synchronized thumb and finger movement tasks while undergoing both EEG and fMRI.
• Dense-array EEG (dEEG) with 256 channels and high-resolution individual head models were used to localize changes in five frequency bands (5-120 Hz).
• EEG-derived localizations were directly compared with fMRI localizations.

Main Results:

• Beta-band (14-30 Hz) desynchronization (power decrease) was the most consistent finding across all participants.
• These beta-band changes were reliably localized to the hand region of the primary motor cortex.
• The localization of beta-band EEG changes strongly aligned with fMRI-identified activity.

Conclusions:

• Beta-band EEG desynchronization during motor tasks provides a reliable and spatially accurate marker of focal brain activity.
• This study demonstrates the congruence between EEG and fMRI in localizing cortical activity related to fine motor control.
• Dense-array EEG, combined with individual head models, offers a viable method for precise functional localization in the motor cortex.