Simultaneous EEG and fMRI in the macaque monkey at 4.7 Tesla

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neuroimaging

Background:

• Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) are powerful tools for understanding brain function.
• Acquisition is challenging due to strong gradient-induced artifacts from magnetic resonance (MR) imaging, limiting combined use.
• Previous methods have struggled to effectively remove these artifacts, especially at high magnetic field strengths.

Purpose of the Study:

• To develop and validate a method for correcting gradient-induced artifacts in simultaneous EEG/fMRI acquisition.
• To demonstrate the feasibility of this method in phantom and in vivo macaque monkey experiments at 4.7 Tesla (T).
• To enable the study of neural processes underlying specific EEG patterns using combined EEG/fMRI.

Main Methods:

• Applied artifact correction techniques to phantom measurements of a 10 microV, 10 Hz signal.
• Conducted simultaneous EEG/fMRI acquisition in an awake behaving macaque monkey at 4.7 T.
• Validated artifact removal by assessing signal amplitude recovery and phase distortion in phantom data and by identifying EEG signals in vivo.

Main Results:

• Achieved 91% amplitude recovery of the phantom signal without phase distortions.
• Successfully extracted artifact-free EEG data from scalp recordings during fMRI acquisition in a macaque monkey.
• Reliably identified visual evoked potentials in the corrected EEG data.

Conclusions:

• Simultaneous EEG/fMRI acquisition is feasible and effective in macaque monkeys at 4.7 T with the developed artifact correction.
• This technique overcomes significant technical hurdles, paving the way for advanced neuroimaging research.
• The method holds great promise for investigating the neural basis of specific EEG patterns in non-human primates.