Non-invasive long-term recordings of cortical 'direct current' (DC-) activity in humans using magnetoencephalography.
Recently, biomagnetic fields below 0.1 Hz arising from nerve or muscle injury currents have been measured non-invasively using superconducting quantum interference devices (SQUIDs). Here we report first long-term recordings of cortical direct current (DC) fields in humans based on a horizontal modulation (0.4 Hz) of the body and, respectively, head position beneath the sensor array: near-DC fields with amplitudes between 90 and 540 fT were detected in 5/5 subjects over the auditory cortex throughout prolonged stimulation periods (here: 30 s) during which subjects were listening to concert music. These results prove the feasibility to record non-invasively low amplitude near-DC magnetic fields of the human brain and open the perspective for studies on DC-phenomena in stroke, such as anoxic depolarization or periinfarct depolarization, and in migraine patients.
Mackert
B M
BM
Neurophysics Group, Department of Neurology, Klinikum Benjamin Franklin, Freie Universität, Berlin, Germany. macbm@zedat.fu-berlin.de
Wübbeler
G
G
Burghoff
M
M
Marx
P
P
Trahms
L
L
Curio
G
G
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005240:Feasibility Studies; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D009146:Music