Matching the proton-magnetic-resonance frequency to the frequency of a periodic neural oscillation (e.g., alpha
or gamma band waves) by magnetic resonance imaging techniques, enables direct visualization of brain functional
connectivity. Functional connectivity has been studied by analyzing the correlation between coherent neural
oscillations in different areas of the brain. In electro- or magneto-encephalography, coherent source
reconstruction in a source-space is very tricky due to power leaking from the correlation among the sources.
For this reason, most studies have been limited to sensor-space analyses, which give doubtful results because
of volume current mixing. The direct visualization of coherent brain oscillations can circumvent this problem.
The feasibility of this idea was demonstrated by conducting phantom experiments with a SQUID-based, microTesla
NMR/MRI system. We introduce an experimental trick, an effective step-up of the measurement B-field
in a pulse sequence, to decouple the magnetic resonance signal from the strong magneto-encephalographic signal
at the same frequency.