Recording is performed inside the shilded room which attenuated the outcoming magnetic and electric noise.
Magentic field is distributed in the clockwise direction against current dipole.
By recording the distribution of magnetic field on the skull, the location of current dipole can be calcurated with the accuracy of milimeters. The absolute locations of auditory cortex, somatosensory cortex and visual cortex can be presented. MEG is possible to localize the auditory cortex, sensory cortex, visual cortex with the accuracy of milimeters. MEG is also possible to localize the abnormal nuronal activity often observed in patients with epilepcy, CVD, anomaly etc. All the test needs reservation.