Mullinger Karen, Brookes Matthew, Stevenson Claire, Morgan Paul, Bowtell Richard
Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy University of Nottingham, Nottingham, United Kingdom.
Magn Reson Imaging. 2008 Sep;26(7):968-77. doi: 10.1016/j.mri.2008.02.014. Epub 2008 May 27.
The increased blood oxygenation level-dependent contrast available at high field makes the implementation of combined EEG/fMRI experiments at 7 T highly worthwhile from the point of view of fMRI data quality, but the higher field poses greater technical challenges for achieving good quality EEG data. A study of the feasibility of recording EEG signals from human subjects at 7 T using a commercially available, MR-compatible EEG system has therefore been carried out. This involved systematic measurement of the sources of noise in EEG recordings made in the 7 T scanner and measurement of RF heating effects on a gel phantom in the presence of a 32-electrode EEG cap. Having found no significant safety concerns and identified a set-up (involving switching off the magnet's cryo-cooler pumps and mounting the EEG amplifier on a cantilever) that limited scanner-induced noise, combined EEG/fMRI experiments employing visual stimulation were then successfully carried out on two human subjects. With the use of beamformer-based analysis of the EEG data, driven responses and alpha-band, event-related desynchronisation were identified in both subjects.
