Controlling the Computer with the Brain
UNTIL RECENTLY, controlling computers by human thought was science fiction, but it's rapidly becoming science
fact. Now researchers have succeeded in tapping directly into thoughts, by implanting tiny electrodes into the brain.
It is called cognitive engineering.
In the classic science-fiction movie Forbidden Planet, space travellers from Earth land on a distant world, where
they encounter the remnants of a technologically advanced civilisation. Remarkably, the human visitors are able to
communicate with one of the alien computers, that is still functioning. Connected through glowing head probes, the
men's thoughts and feelings are directly conveyed to the machine over a neural link.
Many similar examples of people having their minds coupled to computers have appeared in other works of fiction.
As often depicted, a person simply thinks of a command, and the computer immediately responds--a scheme
analogous to the computer voice recognition in use today. Thought recognition would be the ultimate computer
interface, the machine acting as an extension of the human nervous system itself.
Electronic circuits can detect the tiny voltage fluctuations on a person's face that arise when the eyes shift in
orientation. These impulses are called an electrooculographic signal, or EOG (the name for recordings made of
them). EOG signals are used to detect left and right eye motion mapped to left and right cursor motion or on/off
The electrical signal from muscles is called an electromyographic signal, or EMG. EMGs can control program
commands, switch closures, keyboard commands and the functions of the left and right mouse buttons.
The Electro Encephalo Graphic signal describe recordings of voltage fluctuations of the brain that can be detected
using electrodes attached to the scalp. These EEG signals arise from the cerebral cortex, a several-centimeter-
thick layer of highly convoluted neuronal tissue. The signal is continuous and used for control of cursor vertical or
horizontal movement on different signal channels. Most attempts to control a computer with continuous EEG
measurements work by monitoring alpha or mu waves, because people can learn to change the amplitude of these
two rhythms by making the appropriate mental effort. A person might accomplish this result, for instance, by
recalling some strongly stimulating image or by raising his or her level of attention.
(Source: Scientific American 10/96, HUGH S. LUSTED and R. BENJAMIN KNAPP)
The brain-computer interface
Department of Medical Informatics and Ludwig Boltzmann Institute of Medical Informatics and Neuroinformatics