Techniques, devices and systems are disclosed for magnetoencephalography (MEG) source imaging. In one aspect, a method includes selecting signal data associated with one or more frequency bands from a spectrum of the signal data in the frequency domain, in which the signal data represents magnetic signals emitted by a brain of a subject and detected by a plurality of sensors outside the brain, defining locations of sources within the brain that generate the magnetic signals, in which the number of locations of the sources is selected to be greater than the number of sensors, and generating a source value of signal power based on the selected signal data corresponding to a respective location of the locations at the one or more frequencies.
