Advances Boost Mind Control Tech

Electrodes implanted directly into the brain produce much clearer signals, but are not well tolerated by the body. "The brain tries to get rid of [the electrodes] by covering them with a sheet of tissue," explains Schalk. "The signal degrades over time." Schalk and colleagues at Albany Medical College, Washington University in St Louis, University of Washington, Seattle, and the University of Wisconsin at Madison, all US, think a third approach will face fewer hurdles. They cover part of the brain's surface with a polymer sheet containing a grid of electrodes 2 millimetres in diameter and spaced 10 mm apart, a method called electrocorticography (ECOG). Such electrode grids are often placed in people with severe epilepsy to identify the focus of seizures within the brain. "These grids are thin like a sheet of paper," says Schalk. "The electrodes record signals similar to those recorded by electrodes on the scalp, but with much greater fidelity."