Tan Kah Kee Award in Life Sciences
Zhang Xiangtong
Zhang Xiangtong (or, Hsiang-tung Chang) (1907.11-2007.11) was a native of Zhengding, Hebei province. Zhang was neurophysiologist. Zhang graduated from Department of Physiology, Peking University in 1933 and obtained his Ph.D. degree (in Physiology) in Yale University in 1946. He was elected as academician of Chinese Academy of Sciences (CAS) in 1957. He was a Professor in Shanghai Institute of Physiology, CAS from 1957 to 1980. He was appointed as Professor and Director of Shanghai Brain Research Institute, CAS from 1980 until 1984, and served as the Honorary Director of that Institute from 1984 to 1999. He was also a member of Central Council of International Brain Research Organization and an advisor in neuroscience for World Health Organization (WHO).

Zhang was one of the pioneers studying the function of dendrites of central neurons. In early 1950s, he investigated the functional characteristics of apical dendrites of pyramidal neurons in the cerebral cortex with electrophysiological approach. He hypothesized that dendrites were electrically excitable and action potentials could be conducted along apical dendrites. He also emphasized the importance of synapses formed on dendrites: as they are distributed all the way along the dendrites and many are formed within dendritic spines, these synapses may not be as efficient as those on the soma in inducing action potentials in postsynaptic neurons. However, he thought they are paramount important for subtly and accurately regulating and adjusting the excitability of the neurons. Zhang's investigation had large impact at the time and in many years afterwards. His hypothesis that dendrites are able to conduct action potentials, in spite of controversies and objections in more than 30 years, is finally proved to be correct by leading laboratories very recently. Zhang has made other important contributions as well. He made his two classical investigations: Topographical representation of muscles in motor cortex of monkeys and afferent fiber composition in muscle nerves. His discovery, "Light Intensification" phenomenon, was named "Zhang's Effect" by the global physiological circle. Hsiang-tung Chang is also a pioneer in the study of neurophysiological basis of acupuncture analgesia. He and his groups' important contribution in this field is the demonstration that inputs from acupuncture stimulation interact with and thus depress pain-inducing signals at various levels of the central nervous system. This provided a good basis for further in-depth study on the mechanisms. In recognition of his significant contribution to understanding on neural network, he was conferred Lifetime Achievement Award by International Neural Network Society in 1992. He was given Ho Leung Ho Lee Award for Science and Technology Achievement in 2000.