Magnetoencephalography: Evidence of Magnetic Fields Produced by Alpha-Rhythm Currents

Science  23 Aug 1968:
Vol. 161, Issue 3843, pp. 784-786
DOI: 10.1126/science.161.3843.784


Weak alternating magnetic fields outside the human scalp, produced by alpha-rhythm currents, are demonstrated. Subject ard magnetic detector were housed in a multilayer magnetically shielded chamber. Background magnetic noise was reduced by signal-averaging. The fields near the scalp are about 1 x 10-9 gauss (peak to peak). A course distribution shows left-right symmetry for the particular averaging technique used here.