Non-invasive long-term recordings of cortical 'direct current' (DC-) activity in humans using magnetoencephalography
Author(s):, , , ,
Journal/Book: Neurosci Lett. 1999; 273: 159-62.
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.
Keyword(s): Acoustic Stimulation/methods. Adult. Auditory Cortex/physiology. Evoked Potentials, Auditory/physiology. Feasibility Studies. Human. Magnetoencephalography/methods. Music. Support, Non-U.S. Gov't