title: Non-invasive long-term recordings of cortical 'direct current' (DC-) activity in humans using magnetoencephalography.
abstract: 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.
authors.affiliation: Neurophysics Group, Department of Neurology, Klinikum Benjamin Franklin, Freie Universität, Berlin, Germany. macbm@zedat.fu-berlin.de
authors.forename: B M
authors.initials: BM
authors.lastname: Mackert
authors.forename: G
authors.initials: G
authors.lastname: Wübbeler
authors.forename: M
authors.initials: M
authors.lastname: Burghoff
authors.forename: P
authors.initials: P
authors.lastname: Marx
authors.forename: L
authors.initials: L
authors.lastname: Trahms
authors.forename: G
authors.initials: G
authors.lastname: Curio
mesh_terms: 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