The more that is learned about the human brain, the more closely it resembles—insofar as function is concerned —a servo-mechanism. For example, Dr. Wilder Penfield, director of the Montreal Neurological Institute, recently reported at a meeting of the National Academy of Sciences, that he had discovered a recording mechanism in a small area of the brain, which apparently records everything that a person has ever experienced, observed or learned. During a brain operation in which the patient was fully awake, Dr. Penfield happened to touch a small area of the cortex with a surgical instrument. At once the patient exclaimed that she was "reliving" an incident from her childhood, which she had consciously forgotten. Fur­ther experiments along this line brought the same results. When certain areas of the cortex were touched, patients did not merely "remember" past experiences, they "re­lived" them, experiencing as very real all the sights, sounds and sensations of the original experience. It was just as if past experiences had been recorded on a tape recorder and played back. Just how a mechanism as small as the human brain can store such a vast amount of in­formation is still a mystery.
British neurophysicist W. Grey Walter has said that at least ten billion electronic cells would be needed to build a facsimile of man's brain. These cells would occupy about a million and a half cubic feet, and several addi­tional millions of cubic feet would be needed for the "nerves" or wiring. Power required to operate it would be one billion watts.