Magnetoencephalography with a chip-scale atomic magnetometer
Svenja A. Knappe, Tillman H. Sander, Jan Preusser, Rahul R. Mhaskar, John E. Kitching, Lutz Trahms
We report on the measurement of somatosensory-evoked and spontaneous magnetoencephalography signals with a chip-scale atomic magnetometer. This uncooled, fiber-coupled sensor has a sensitive volume of 0.58 mm3 inside a sensor head of volume 1 cm3. When positioned over O1 of a healthy human subject, ∝-oscillations were observed in the component of the magnetic field perpendicular to the scalp surface, when the subject was verbally instructed to close his eyes. Furthermore, somatosensory-evoked fields were measured by stimulation at the right wrist of the subject and placing the sensor over C3. The N20m brain response was clearly visible in the averaged data, recorded with the chip-scale optical magnetometer, and confirmed by comparison with equivalent data from a SQUID magnetometer.