The brain processes information using both slow and fast currents. Until now, researchers had to use electrodes placed inside the brain in order to measure the latter. For the first time, researchers from Charité – Universitätsmedizin Berlin and the Physikalisch-Technische Bundesanstalt (PTB) have successfully visualized these fast brain signals from the outside—and found a surprising degree of variability. According to their article in PNAS, the researchers used a particularly sensitive magnetoencephalography device to accomplish this feat.