Everything You Always Wanted To Know About the Brain

By R.Z. Sheppard

MAN AND MEMORY: BREAKTHROUGHS IN THE SCIENCE OF THE HUMAN MIND by D.S. Halacy Jr. 259 pages. Harper & Row. $6.95.

Here is everything you always wanted to know about the brain but were afraid to ask. For example, does size really make a difference?

Unfortunately, yes. The average male human brain weighs three pounds, a size exceeded only by the brains of elephants, sperm whales and dolphins. However, it is the ratio of total body weight to brain weight that is more important. In this respect, of the three above, only the dolphin compares favorably with man.

The critical mass of the human brain is the cortex, a wrinkled grayish pink covering. It is the seat of such processes as thinking, judgment, speech and that tricky blessing, memory. According to D.S. Halacy Jr., an experienced popularizer of science, if the cortex were ironed flat, it would approximate the size of a newspaper page. Whether regular or tabloid size remains anybody's guess. But then, as Halacy makes totally clear, all the really important things about the brain are mysterious.

The most teasing of the brain's secrets is just what is the physical basis of memory. Halacy notes that there are scientists who despair of ever solving that one, on the theory that the brain, by its nature, cannot fully define itself.

Fortunately there are men and women who are too busy studying the brain to bother with sorting out such semantic eels. The big conceptual problem has been to come up with a model, or analogue, that will explain the dynamics of learning and memory. Although there are minds that warp and others that gather wool, Lord Sherrington's definition of the brain as an "enchanted loom" is more poetic than precise. The electronic computer at first seems promising. Unhappily, though the brain generates and can be prodded by electrical impulses, the most sophisticated cybernetic device is still a primitive instrument when compared with the human brain.

The theory that learning and memory are dependent on molecular chemical groupings and regroupings seems more promising. Halacy surveys the major researches in this area, including controversial experiments in which trained flatworms were minced and fed to untrained flatworms. In equally controversial tests, the latter apparently cannibalized the former's acquired knowledge, which is believed to have been contained in RNA molecules that were coded during training. As late as the mid-'60s, chemicals such as glutamic acid were thought to increase alertness in humans and even to boost IQ scores. Alas, the latest word from the lab seems to be that an intelligence pill is not around the corner.

Part of the problem in writing about the brain has to do with language and loosely defined terminology. Halacy's brisk reportage, use of quaint diagrams and illustrations, and obvious enthusiasm for scientific breakthroughs tend to overshadow the innumerable qualifications he must employ. For the present, perhaps all that we can be certain of is Ambrose Bierce's definition of the brain: "An apparatus with which we think that we think."

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