Potential distribution of vertex sharp wave and saw-toothed wave on the scalp

Potential distribution of vertex sharp wave characterizing stages 1 and 2 of NREM sleep and saw-toothed wave recorded in REM sleep were studied in 6 healthy young adults. Like the vertex sharp wave, saw-toothed wave appeared in a wide area on the scalp with the maximal amplitude at Cz and its equipotential lines showed concentric circles with their center at Cz, its amplitude decreasing with distance from Cz. The main component of saw-toothed wave was a positive wave with longer duration (about 250 msec) and lower amplitude than vertex sharp wave (about 200 msec in duration), the main component of which was a negative wave.