The Human Brain
Probing the Awesome Power of the Human Brain
A PRETTY Berkeley coed with electrodes pasted to her head reclines in an easy chair and closes her eyes. A look of beatific serenity gradually suffuses her face, and a soft, eerie tone arises from a loudspeaker. The tone tells the girl that she has learned, as hoped, to generate alpha waves, an electrical pattern in her brain that some scientists link to a yoga-like inner peace, a special state of relaxed awareness.
# At Boston City Hospital, a housewife awaits peace of a different sort. For 20 years she has suffered from epileptic seizures which recently have triggered such uncontrollable rage that she has several times beaten her small son severely. Now neurosurgeons plan to destroy the tiny cluster of abnormally functioning nerve cells in her brain that are related to her seizures by raising the temperature of the area with electricity.
# In another hospital, a 29-year-old man, tortured to the brink of suicide by spells of depression, walks into a laboratory. On his shaved skull are the terminals or electrodes implanted in his brain three months before. After doctors have hooked the wires to a metal control box, the patient merely presses a button and a sensation of pleasure is induced that is, by his own description, “better than sex.”
Until the seventies, such dramatic treatments were much the stuff of science fiction. No longer, thanks to the ever more exciting work of the probers of the three pounds of pinkish-gray jelly that make up the human brain.
Similar techniques ad treatments are fast finding growing acceptance in laboratories and hospitals across the nation. And as they do, many scientists have begun to talk with awe of the prospects that brain research may hold for the future. Some speak of “memory molecules” and the possibility of learning anything from basic French to integral calculus by taking the appropriate pill. Others discuss the possibility of eventual genetic engineering of men with super brains- brains with capacities beyond Einstein’s or talent beyond Bach’s. a few profess even to foresee the creation of a sort of totally rational super-creature-with complete mastery over the drives that contribute to war, poverty and most of the rest of man’s miseries.
Intricate Interplay. For the moment, however, the most dramatic work of the brain researchers turns on strides being made in fundamental research on the brain itself, whose major motor and sensory areas, as well as constituent parts, are already fairly well charted. At the top of the spinal cord lies the brain stem, which is critically involved in respiration, blood pressure and other involuntary functions essential to life. The top part of the brain stem and deeper part of the cerebral cortex (paleocortex or “old bark”) comprise the “limbic system.” Which plays a key part in controlling the emotions and basic drives of fear, hunger, pleasure and sex. At the rear of the brain lies the cerebellum (little brain), which regulates fine coordination. The top of the cerebral cortex is the neocortex (new bark), which not only governs movement and the senses, but also permits man to acquire new skills and gives him rational control over his baser drives.
This intricate interplay has been compared depending on the technology of the time, to everything from the shuttles of a loom to the high-speed computer. But the circuits of the brain are infinitely more complex. And in trying to decipher the brain’s wiring plan scientists are putting some old ideas to rest and making surprising new discoveries about the pathways of perception, learning and emotion.
When Down is up. For nearly 50 years, most researchers held that all neurons were more or less alike and had adapted to specialized roles through the influence of environment and experience. Now they know that at least some neurons are genetically ordained for remarkably specific tasks. For example, during world war ll, Caltech’s Roger Sperry cut the optic nerves of frogs and newts and rotated their eyes 180 degrees. When the nerves regenerated, as they do in amphibians, the animals saw upside down: if food was dangled overhead, they didn’t jump up, but dived down, to each it. Sperry concluded that the nerve cells of the eye were programmed to reconnect with only one specific point in the brain; they could not randomly seek out a new hookup that would permit the animal to see right side up.
But, although many neurons are committed to perform specific tasks in the brain, they are by no means unique and irreplaceable. “If they were,” said the late Hans-Lukas Teuber, then with the Massachusetts Institute of Technology, “we couldn’t bear losing hundreds of them every day through aging.” Indeed, the brain often shows remarkable powers of recovery from injury. If, say, the speech regions on the left side of the brain are destroyed early in life, speech is likely to develop in the corresponding areas of the right side. (For an adult, recovery is far less dramatic.)
Today’s researchers, moreover, are increasingly persuaded that the source of man’s hungers, drives and moods lies in the brain’s neuronal circuits. And their recently acquired knowledge about testing brain activity in patients with brain disorders has led to the precise procedures of psychosurgery. In one of these, a thin electrode is inserted through a small hole in the patient’s skull, and a segment of the limbic system is electrically destroyed. Dr. H.Thomas Ballantine, of Massachusetts General Hospital, found that eight of ten patients with severe manic-depressive psychosis show resulting improvement with no adverse side effects.
At Boston City Hospital, neurosurgeon Vernon Mark and psychiatrist Frank Ervin have employed electrical stimulation of the brain and other forms of neurosurgery to test and record persons subject to violent outbursts of rage that are associated with psychomotor seizures or limbic epilepsy. While the patient lies conscious surgeons implant electrodes in various areas of the brain. Later they apply a weak electrical current and wait for the patient to show signs of a psychomotor seizure which may include a rage attack (one patient struck a technician in the jaw). Once the area responsible for the disturbance has been located, it is inactivated by heat.
Electronic Matador, In the field of electrical stimulation of the brain (ESB), the most headline-catching experiment came several years ago when Yale’s Dr. Jose Delgado stopped a charging bull in its tracks by stimulating electrodes in the animal’s brain with remote-control radio waves. At the Stanford Research Institute in the mid-to-late sixties, psychologist Law-rence Pinneo used ESB to control the limbs of brain-damaged monkeys. A computer transmits to electrodes in the monkey’s brain stem impulses resembling those that would normally flow from its cerebral cortex, and the monkey is then able to perform simple movements with its hitherto disabled limbs. When perfected for humans, Pinneo’s system could perhaps permit the victims of strokes or other brain injuries to regain some control over their movements by using ESB to bypass the disabled cortex.
Perhaps not surprisingly, it is prospect that man may be able to use his own brain to control his most involuntary functions that will attract the most attention among laymen. This is the technique called biofeedback. Until several years ago most reputable scientists didn’t think it was possible. But then Neal E. Miller and Leo V. DiCara, New York’s Rockefeller University, announced that they had trained rats to alter visceral activities such as heart rate and urinary output by operate conditioning –conventional reward-and-punishment learning.
At the time, it was firmly believed that the autonomic nervous system that controls such functions was too primitive to respond to teaching methods usually applied to the cerebral cortex. I one experiment, rats were rewarded by bursts of electricity from an electrode buried in the pleasure regions of the hypothalamus each time their heart rates dropped to a pre-determined level, until they achieved a steady 20-percet reduction. Ultimately some rats learned highly specific control, and could actually make one ear blush and not the other. Investigators have tried to determine whether patients can use this kind of conditioning to improve their health. At the Gerontology Research Center in Baltimore, to control potentially lethal irregularities in heart rhythm, Bernard T. Engel and his colleagues trained eight persons to slow their heartbeat by concentrating intensely when a red light appeared and to speed up the beat at a green light. Ultimately, they learned to maintain a safe mid-pace indicated by a steady yellow light.
Still experimental, biofeedback is also being tested in the treatment of high blood pressure and a number of psychosomatic diseases including asthma and migraine headaches. In one of the more exotic applications of the technique, volunteers learn to turn on the alpha waves of their brains, hopefully to achieve alpha’s special state of relaxed awareness. Prof. Donald B. Lindsley, professor emeritus of psychology at the University of California at Los Angeles, thinks that such brain-wave studies may help define the times when children are most receptive to schoolwork.
A Pill for French? None of the objectives of basic brain research, however, is given greater weight in the implications for man’s future than an understanding of memory and the learning process. What determines whether a memory becomes lastingly fixed in the brain, according to Dr. Robert Livingston, of the University of California at San Diego, is the “now-print” mechanism that informs the brain that what is happening is worth remembering. The fact that almost everyone can recall precisely where he was and what he was doing. When he heard the news of President Kennedy’s assassination is a classic example of now-print, says Livingston.
It is the implication that chemicals, including proteins, play a role in such memory storage that underlies all the talk about a pills to improve the mind. Thus, a number of scientists have reported finding peptides derivatives of proteins, in increased amounts in the brains of animals after training. And some have even claimed to transfer skills to untrained animals by injections of peptides removed from these brains. One of the most impressive of these experiments came from the late Dr. Georges Ungar, of Houston’s Baylor College of Medicine. Ungar conditioned some 4000 rats to fear the dark by subjecting them to mild electric shocks each time they chose a dark passage over a brightly lighted one. From their brains, he isolated a compound that he called “scotophobin,” injections of which, he claimed, induced fear of the dark in unconditioned animals.
Even so, many scientists remain highly skeptical of an injection or a pill that could impart any kind of learning. For the most part, they point out, drugs improve deficient function, but do not boost normal function. “Drugs function at the level of emotion, not cognition,” said Dr. Seymour Kety, of McLean hospital in Belmont, Mass. “I don’t see how you could make one that would teach French.”
Australian-born Sir John Eccles, who won a Nobel Prize in 1963 for his work on the transmission of impulses between neurons, agreed, but added, “In this business we’ve learned that everything is possible. We’re always learning, learning, learning.” For Eccles, the search for a understanding of the brain is like charting continents, and each new landmark produces yet another challenge. “The more heights you reach, the more country you see that looks interesting.”