Mental Changes Resulting from the Passage of Small Direct Currents Through the Human Brain

Abstract

The passage of small direct currents through nerve cells gives rise to changes in their excitability. For example an outward current flow through the membrane of the soma gives rise to depolarization and a consequent fall in the threshold for excitation of the neurone. When a cell lies in an applied external electrical field a potential gradient exists between the cell body and its distant processes. If this gradient is such that the cell body is negative relative to its processes, the cell becomes more excitable; it becomes less excitable when the cell body is relatively positive.