Figure 1. Measurement of somatosensory-evoked magnetic fields for the hard palate. (A) Anatomical diagrams showing 3 stimulation sites for the palate. (B,C) The Ag-AgCl electrodes (approximately 2.5 mm between electrodes) were embedded in a custom-made plastic splint attached to the maxillary dentition to obtain a fixed stimulus position. (D) Typical examples of whole-scalp magnetic responses of somatosensory-evoked magnetic fields following stimulation of the right first transverse palatine ridge. Traces are plotted on the "flattened head", as viewed from above with the person’s nose upwards. Each trace began 100 msec prior to and ended 300 msec after stimulus onset. Circles indicate channels showing prominent magnetic signals. (E) Enlarged superimposed traces of the somatosensory-evoked magnetic field evoked by right-side stimulation of the first (upper) and third transverse palatine ridges (middle), and the greater palatine foramen (lower). The 3 successive identifiable peak signal components were designated 1M, 2M, and 3M.