The Chemistry of Thought

What is mind?

No matter!

What is matter?

Never mind!

To man through most of history, the mind has seemed too marvelous to be made up of mere matter. Yet it obviously consists of some arrangement of molecules in the brain that work collectively to remember and reason. Last week in San Francisco, a score of the world's most eminent scientists of the mind heard Swedish Neurobiologist Holger Hyden (pronounced he-dam), 43, offer a theory about the chemistry of thought. Hyden, who is chief of tissue studies at the University of Goteborg, even named a chemical that dictators might use to disrupt the thought process and enslave the minds of their subjects.

Man's brain, explained Professor Hyden, contains two main types of cells: neurons and glial cells. The neurons are giant, as cells go, with elaborate systems of filaments connecting them to other neurons. The smaller glial (meaning gluey) cells stick to the neurons like caviar on a canape. Hyden and his colleagues at Goteborg, by exquisitely delicate techniques, have separated neurons from their adherent glial cells and have weighed them in units as small as millionths of a millionth of a gram. By taking fresh, still-living cells from a rabbit's brain, the Hyden team has been able to find out how they use and convert their chemical fuels under varying conditions.

Spinning Rabbits. The neuron's basic function is to transmit "nerve impulses" by high-speed electrochemical reactions. Hyden's team devised an ingenious way to find out what happens to nerve cells when they receive a stimulus. The scientists spun rabbits on a centrifuge, just fast enough to make them dizzy and cause the cells in the acoustic nerve and the vestibular apparatus of the inner ear (a center of balance) to stimulate the brain with a sense of distress. Then they painlessly killed the animals and analyzed the nerve cells.

Stimulation, they found, resulted in a marked increase in the neurons' content of enzyme proteins, while the glial cells showed a corresponding drop. The glial cells behave like the self-sacrificing wife who eats mostly potatoes and gives the high-energy meat to her ditchdigger husband. The "information" contained in the protein which the neuron forms, reasons Hyden, becomes the impulse that the neuron sends along the filaments to other neighboring neurons.

Modified Proteins. The higher brain functions of memory and reasoning, Hyden hypothesizes, are achieved by the way the neuron alters the protein it forms. Each neuron contains millions of molecules of ribonucleic acid (RNA). Each of these molecules is chemically keyed by the arrangement of its internal building blocks. These molecules dictate, in accordance with their keys, the nature of the proteins that the neuron forms, in cooperation with the glial cells. The modified proteins are the chemical representations of thoughts.

Memory is thus the imprinting of a code on RNA molecules in millions of cells, like punch holes in a set of IBM cards. For example, an impulse caused by the ear's hearing "concert A" scurries from cell to cell until it finds those containing RNA molecules already keyed to respond to that note, and it is this chemical response that constitutes recognition of the note. The average human brain has ten billion neurons, so the number of possible permutations is astronomical. Further, said Dr. Hyden, this theory explains why neurologists have been unable to find precise centers in the brain for most higher mental functions: through its content of many imprinted molecules, each neuron may participate simultaneously in many neuronal networks--and therefore in many memories and complex thoughts.

Brainwasher on Tap. The next thing was to learn whether mental function can be chemically controlled. It can, said Dr. Hyden. Small doses of a new synthetic substance called tricyano-amino-propene ("triap") caused drastic changes in neuronal RNA and proteins in animals--and, according to preliminary studies, in man.

"There is now evidence," said Hyden, "to prove that the RNA and enzyme changes are followed by an increased suggestibility in man. A defined change of functionally important substances in the brain could be used for conditioning a whole population." A police state government, he theorizes, could add such substances to tap water and brainwash the whole population at once.

Dr. Hyden's picture of the possibilities was not all dark. Chemical countermeasures to reverse the brainwashing are "not difficult to imagine," he said. And where mental disease can be shown (as a few uncommon forms have been) to result from a metabolic defect, the defect might be remedied by chemical stimulation of the neurons.

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