Magnetoencephalographic response characteristics associated with tongue movement.

Whole-head magnetoencephalography (MEG) was employed to study the sources of activation evoked by both active tongue movement and swallowing in five healthy subjects. Evoked magnetic fields were adequately explained in both paradigms by a time-varying single-dipole model which localized in the tongue in all subjects. No additional brain sources were detectable. Therefore, MEG detects fields associated with tongue movement that best fit a single-dipole source in the tongue. Future electrophysiological brain activation studies where tongue movement is likely should be aware of this observation since the tongue behaves like a strong current dipole.