The technique involves placing electrodes on the scalp of the head and applying random electrical noise to stimulate parts of the brain and encourage nerve cells to fire. In this case the electrodes were placed on the head to target regions of the brain known to be involved in doing maths.
Electrical boost to mental arithmetic powers
19 May 2013
A weak electrical signal can boost people's powers of mental arithmetic over a period of months, suggests a small scale study at the University of Oxford.