On tickling brains to investigate minds

Stimulating the brain by either direct or eddy electrical currents for medical and research purposes has a long history. One of the first records dates back to 43AD and is attributed to Scribonius Largus, physician of the Roman Empire, who reported the treatment of migraines and headache through application of electrical currents with the torpedo fish. In the 15th century, Paracelsus suggested that magnetic forces can promote self-healing, and in the 18th century French physician Charles Le Roy started to experiment with electricity as a means to influence psychological function. Although he did not succeed in restoring vision to a blind patient by winding conducting wires around the patient’s head, he did manage to make him perceive vivid flashes of light (phosphenes). Noninvasive electrical stimulation, however, was associated with painful sensations and continued to be the main stimulation device for experimental and medical treatments even after the discovery, in the first half of the 19th century by Michael Faraday, that a changing magnetic field can induce an electric current in a conducting means. It was only with Jacques