Neuromagnetism and Source Location
According to the electromagnetic theory, bioelectric currents within the brain produce electric and magnetic field phenomena. The measurement of the electric potentials at the surface of the head results in the EEG. The detection of the external magnetic fields yields the magnetoencephalogram (MEG). MEG recording is a contactless technique and does not require a reference electrode, as does the EEG. EEG is still the main tool of noninvasive detection of brain activity, but MEG seems to be influenced less strongly by intervening tissue. For this reason, MEG is expected to be more effective in the three-dimensional localization of current sources. However, the spatial source localization can be performed only on the basis of apropriate physical models for the field sources and the head.
KeywordsCurrent Source Magnetic Field Component Current Dipole Dipole Layer Spherical Head Model
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