Brain Broadcasts

When sensitive electrodes are fastened to the head, they pick up tiny electrical impulses from the brain. These impulses can be amplified, measured and traced to specific nerve cells. The man who thus tuned in on the brain was Dr. Edgar Douglas Adrian, fellow of Trinity College, Cambridge, who won a Nobel physiology prize for his discovery in 1932. Last week Dr. Adrian reported his progress in this scientific eavesdropping. The messages he has picked up from the brain, he told an audience of distinguished scientists in the second Pilgrim Trust Lecture in Washing ton, have so far been vague and rather crude, but he has heard enough to make him hopeful that some day an electrical listening post will be able to report what, if anything, a brain is thinking.

Nerve cells, Dr. Adrian found, give off electrical waves (resulting from changes in potential) when they are stimulated. The nerve impulses that set off these brain waves all seem to be of the same kind, regardless of where the stimulation comes from. What distinguishes the sense signals from one another is the place in the brain where they are received: a visual image, for example, is recorded in one area of the brain, a hearing image in another.

By moving his electrodes on a subject's head, Dr. Adrian located these areas definitely, and also located the image. Thus, when a subject looked at a cross of light, electrical impulses defined a cross-shaped area at the back of the occipital lobe of the brain. A sound heard by the subject likewise made a brain image of a characteristic shape. Dr. Adrian observed that he had not yet discovered the shape of a violet's smell but he is confident that eventually he will.

When he showed a subject a flickering light, his brain-broadcasting instrument recorded flickering electrical impulses of the same frequency. This experiment revealed "an interesting borderland" between the visual area and the rest of the brain -- the image spread out over a wider area, into parts of the brain not primarily concerned with sight. Dr. Adrian suggests that this spreading activity in the brain represents the reaction of the brain cells to the image, i.e., an approach to thinking. But his recordings of this complex process are so confusing and difficult to interpret that "the present technique of recording brain events, by oscillographs connected with electrodes on the head, is not likely to lead very far." Nonetheless, Dr. Adrian is sure, on the basis of progress already made, that new instruments will be developed that will be able to record "brain events" in much greater detail.

Then, says Dr. Adrian, "an electrical survey could scarcely avoid giving some entirely novel information about what is happening in the brain when we think or solve problems or decide what to do."

This file is automatically generated by a robot program, so reader's discretion is required.