N. A digital low pass filter at 30 Hz was applied on the averaged signals for further analysis. The subject was a healthy male whose median nerve of the right wrist was electrically stimulated. The MEG signals from 160 ch sensors. A large peak at 0 ms is an artifact noise from a somatosensory stimulator. An isofield contour map of the data set at 20.5 ms of latency.
Dots mean locations of sensors.
Top and bottom correspond to forehead and occipital region, respectively. One step corresponds to 10 fT change. Dark gray lines represent outgoing fields of the head. Light gray lines represent incoming fields. The first peak of the evoked fields appeared at 20.5 ms after stimulus.