Is the neuromagnetic field in the human brain detectable by MRI in practice?
Mandelkow H, Halder P, Brandeis D, Boesiger P, de Zanche N
University and ETH Zurich
We explore the possibility for direct detection of neuronal currents by fast dynamic MRI in conjunction with fully simultaneous recordings of the EEG. Specifically, our experiment is designed to localize the current source of alpha waves by analyzing the spectral coherence of EEG channel and MRI voxel time series recorded simultaneously in human subjects. A phantom containing a dipolar current source was constructed to determine the sensitivity of the measurement and to validate the analytical approach. The analysis of our in-vivo and in-vitro data indicates that a moderate improvement in SNR may render alpha waves detectable by this kind of correlation analysis, but the specificity of any such approach may be limited due to physiological confounds like cardiac pulsation.