Optically pumped magnetometers enhance neuroimaging performance-An EEG, OPM, and SQUID-MEG study

Much of our understanding of how neural circuit activity relates to human behavior and cognition stems from non-invasive assessments of the central nervous system. Further progress on key questions, however, requires measurements with a higher signal-to-noise ratio (SNR). Here, we show that in an established 40 Hz auditory steady-state paradigm, optically pumped magnetometers (OPMs) significantly outperform not only electroencephalography (EEG) but also conventional magnetoencephalography (MEG) in SNR and inter-trial phase coherence (ITPC). SNRs of OPMs were increased by up to 205% compared to EEG and by up to 40% compared to conventional MEG. As few as 10-16 OPM sensors were sufficient to significantly outperform 56 EEG electrodes. To maximize the representation of evoked responses, we employed spatial filters, which greatly enhanced SNRs across measurement modalities. Our data provide evidence for the potential of OPMs to enhance non-invasive neuroimaging, paving the way for important advances in basic as well as translational neuroscience.