Emotional Circuits

Last week Dr. James Weneeslas Papez, professor of anatomy at Cornell University, had a heavy mail. He had published in Archives of Neurology and Psychiatry a paper entitled A Proposed Mechanism of Emotion, which many experts considered to be the most coherent and logical explanation of human emotion yet devised by science. It was the first complete account, in physiological terms, of the evolution of a simple nerve impulse into a colorful, complex emotional experience. Queries and requests for reprints were coming in by dozens and scores.

In the human brain the cerebral cortex, whose outer layers are visible in pickled specimens as the familiar wrinkled folds which look like sweetbreads, is the seat of reason and intellection. It is also the seat of emotional consciousness. But consciousness is not a process; it is an end-product. The mechanisms which produce emotional consciousness appear to be situated in the diencephalon, a central cluster of organs which is enfolded by the cerebral hemispheres.

Dr. Papez singled out four bodies in the region of the diencephalon, with their numerous nerve connections, and postulated for them a new relationship. "Taken as a whole," he said, "this ensemble of structures is proposed as representing theoretically the anatomic basis of emotions." The four, and their functions according to Dr. Papez:

The hypothalatnus, a wedge-shaped object which serves as a clearing station for sense impressions coming in from the body.

The mamillary body, a small spheroid organ which is one of the three principal parts of the hypothalamus. It lies at one corner of the hypothalamus and picks up impulses from the hypothalamus and transmits them to

The gyrus cinguli, a belt-shaped organ lying above the thalamic region. This is the receiving gate for impulses going into the cerebral cortex. It appears to be the seat of vigilance and of sex emotions.

The hippocampus, connected with the mamillary body, is shaped like its namesake, the seahorse. The hippocampus builds up psychic emotion.

Psychic emotion occurs when a man sits down and gets angry by thinking about wrongs done to him by an enemy. In psychic emotion, therefore, the emotional impulse is initiated within the brain--that is, by the cerebral cortex. The incitation passes to the hippocampus, where it is built up into an emotional process. This passes through the mamillary body, thence to the gyrus cinguli and so back to the cortex where the emotional experience is felt.

Sensory emotion occurs when a child gets angry at a chair against which he has bumped his knee. The sense impressions reach the hypothalamus, where they become an emotional process. It emerges from the hypothalamus through the mamillary body and passes to the cortex by way of the gyrus cinguli.

Conclusion: "Is emotion a magic product, or is it a physiologic process which depends on an anatomic mechanism? . . . The evidence presented is ... suggestive of such a mechanism as a unit within the larger architectural mosaic of the brain."

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