Edelman , Gerald Maurice

(1929–) American biochemist

Born in New York City, Edelman was educated at Ursinus College, the University of Pennsylvania, and Rockefeller University, where he obtained his PhD on human immunoglobulins in 1960. He remained at Rockefeller where he was appointed professor of biochemistry in 1966 and Vincent Astor Distinguished Professor in 1974. Edelman left Rockefeller in 1992 to set up and direct the Neuroscience Institute at the Scripps Research Institute, La Jolla, California.

Edelman was interested in determining the structure of human immunoglobulin. The molecule is very large and it was first necessary to break it into smaller portions, which was achieved by reducing and splitting the disulfide bonds. Following this, Edelman proposed that the molecule contained more than one polypeptide chain and, moreover, that two kinds of chain exist, light and heavy. Such studies helped Rodney Porter propose a structure for the antibody immunoglobulin G (IgG) in 1962.

Edelman was more interested in attempting to work out the complete amino-acid sequence of IgG. As it contained 1330 amino acids it was by far the largest protein then attempted. By 1969 he was ready to announce the results of his impressive work, the complete sequence, and was able to show that while much of the molecule was unchanging the tips of the Y-like structure were highly variable in their amino-acid sequence. It thus seemed obvious that such an area would be identical with the active antigen binding region in Porter's structure and that such variability represented the ability of IgG to bind many different antigens. It was for this work that Edelman and Porter shared the 1972 Nobel Prize for physiology or medicine.

Edelman has also speculated on antibody formation and the mechanism behind the spurt in production after contact with an antigen. In the former area he argued in 1966 for a major modification of the clonal theory of Macfarlane Burnet. In the latter case he suggested, in 1970, that the signal to the immune system to increase production is set off by the change in shape of the antibody molecule as it combines with its antigen.

Following his biochemical successes Edelman turned to the neurosciences. In such works as Neural Darwinism (1987) andBright Air, Brilliant Mind (1993), he produced a distinctive theory of the development and nature of the mind. We are, he claims, at the beginning of a neuroscientific revolution from which we will learn “how the mind works, what governs our nature, and how we know the world.”

Edelman was struck by a number of similarities between the immune system and the nervous system. Just as a lymphocyte can recognize and respond to a new antigen, the nervous system can respond similarly to novel stimuli. Neural mechanisms are selected, he argued, in the same manner as antibodies. Although the 10⁹ cells of the nervous system do not replicate, there is considerable scope for development and variation in the connections that form between the cells. Frequently used connections will be selected, others will decay or be diverted to other uses. There are two kinds of selection: developmental, which takes place before birth, and experiential. There are also innate ‘values’ – built in preferences for such features as light and warmth over the dark and the cold.

In Edelman's model, higher consciousness, including self-awareness and the ability to create scenes in the mind, have required the emergence during evolution of a new neuronal circuit. To remember a chair or one's grandmother is not to recall a bit of coded data from a specific location; it is rather to create a unity out of scattered mappings, a process called by Edelman a ‘reentry’. Edelman's views have been dismissed by many as obscure; some neurologists, however, consider Edelman to have begun what will eventually turn out to be a major revolution in the neurosciences.