Neural Crest Cells and Axonal Specificity
Adapted from D. Purves and J. W. Lichtman 1985. Principles of Neural Development. Sinauer Associates, Sunderland, MA.
Viktor Hamburger was born in Landeshut, Silesia (now a part of Poland, but then a province of Germany). Although his father was a businessman, much of Hamburger's youth was spent in a rural setting where his interest in biology was encouraged by teachers and a friend, who was later a leading taxonomist at the Berlin Museum of Natural History. He attended the Universities of Breslau, Heidelberg, Munich, and Freiburg and received his Ph.D. in zoology under the supervision of H. Spemann in 1925. He then took a post as a research associate at the Kaiser Wilhelm Institute for Biology in Berlin in the laboratory of 0. Mangold and, after two years, became a privatdozent and instructor at the Zoological Institute of the University of Freiburg).
In 1932, Hamburger received a yearlong Rockefeller fellowship to work in F. R. Lillie's laboratory at the University of Chicago, one of the few laboratories in the world then studying the embryology of the chick; his purpose was to apply Spemann's microsurgical methods to the chick embryo. When he arrived in Chicago in 1932, his intention was to stay only a year. However, the rise of the Nazi party in early 1933 resulted in a letter from the dean of the faculty at the University of Freiburg informing Hamburger that, due to "the cleansing of the professions," he had been dismissed from his position in Germany. Thus, he stayed on as a Rockefeller fellow at the University of Chicago until 1935, when he was appointed to the zoology faculty at Washington University in St. Louis, where he has remained.
Hamburger's research proceeded along four different but related lines. The first of these, fundamental to the other three, was his classic study of the normal development of the chick embryo. "Our real teacher," Hamburger said, "has been and still is the embryo-who is, incidentally, the only teacher who is always right" (Holtfreter, 1968). Because of Hamburger's work, this preparation now provides the standard for much vertebrate neuroembryology; the staged series published with H. Hamilton (Hamburger and Hamilton, 1951), which summarizes the major developmental landmarks of the chick, is one of the most cited papers in the biological literature.
The second avenue of Hamburger's work, and perhaps the most important, concerned the discovery and elucidation of neuronal death in normal embryonic development. A number of earlier investigators had noted that removal of a peripheral target-for example, the limb bud in a tadpole or a chick embryo-resulted in developmental failure of the related nerve centers. Hamburger, with his colleague R. Levi-Montalcini, showed that normal nerve cell death is also dictated by the peripheral target. These studies on normally occurring neuronal death in the chick embryo form the basis for present thinking about competitive processes in the nervous system.
The third line of Hamburger's research was his discovery with Levi-Montalcini in the late 1940s and early 1950s of the protein nerve growth factor (Levi-Montalcini and Hamburger, 1951). Since the 1950s, work in numerous laboratories has characterized the nerve growth factor molecule and established a good understanding of its biological significance.
The final line of Hamburger's research concerned the development of behavior. Using his knowledge of the normal development of the chick embryo, Hamburger explored the earliest stages of embryonic motor activity in a series of experiments carried out in the 1960s. Contrary to the view widely held by behavioral psychologists, he showed that the earliest movements of embryos are independent of sensory stimulation (Hamburger et al., 1966).
To a remarkable degree, Hamburger's work has set the course of developmental neuroembryology in this century. However, only in the last decade or so have neurobiologists (as distinguished from embryologists) recognized the fundamental significance of his contributions.
Hamburger, V. and Hamilton, H. L. 1951. A series of normal stages in the development of the chick embryo. J. Morphol. 88: 49-92.
Hamburger, V., Wenger, E., and Oppenheim, R. 1966. Motility in the chick embryo in the absence of sensory input. J. Exp. Zool. 162: 133-160.
Holtfreter, J. 1968. Address in honor of Viktor Hamburger. In Locke, M. (ed.) The Emergence of Order in Developing Systems. The Twenty-Seventh Symposium of the Society for Developmental Biology. Academic Press, NY. IX-XX.
Levi-Montalcini, R. and Hamburger, V. 1951. Selective growth stimulating effects of mouse sarcoma on the sensory and sympathetic nervous system of the chick embryo. J. Exp. Zool. 116: 321-361.