Sir John Carew Eccles (January 27, 1903 - May 2, 1997) was an Australian neurophysiologist who won the 1963 Nobel Prize in Physiology or Medicine for his work on the synapse. He shared the prize together with Andrew Fielding Huxley and Alan Lloyd Hodgkin.

John Eccles, shown here at his lab bench

Research

In the early 1950s, Eccles and his colleages performed the key experiments that would win Eccles the Nobel Prize. To study synapses in the periphrial nervous system, Eccles and colleagues used the stretch reflex as a model. This reflex is easily studied because it consists of only two neurons: a sensory neuron (the muscle spindle fiber) and the motor neuron. The sensory neuron synapses onto the motor neuron in the spinal cord. When Eccles passed a current into the sensory neruon in the quadriceps, the motor neuron ennervating the quadricep produced a small excitatory postsynaptic potential (EPSP). When he passed the same current through the hamstring, the opposing muscle to the quadricep, he saw an inhibitory postsynaptic potential (IPSP) in the quadricep motor neuron. Although a single EPSP was not enough to fire an action potential in the motor neuron, the sum of several EPSPs from multiple sensory neurons synapsing onto the motor neuron could cause the motor neuron to fire, thus contracting the quadricep. On the other hand, IPSPs could subtract from this sum of EPSPs, preventing the motor neuron from firing.

Apart from these seminal experiments, Eccles was key to a number of important developments in neuroscience. Until around 1949, Eccles believed that synaptic transmission was primarily electrical rather than chemical. Although he was wrong in this hypothesis, his arguements led himself and others to perform some of the experiments which proved chemical synaptic transmission. Bernard Katz and Eccles worked together on some of the experiments which elucidated the role of acetylcholine as a neurotransmitter.

Biography

Eccles was born in Melbourne, Australia. He graduated from Melbourne University in 1925. He was awarded a Rhodes Scholarship to study under Charles Scott Sherrington at Oxford University, where he received his Doctor of Philosophy in 1929. In 1937 Eccles returned to Australia, where he worked on military research during World War II. After the war, he became a professor at the University of Otago in New Zealand. From 1952 to 1962 he worked as a professor at the Australian National University. He won the Australian of the Year Award in 1963, the same year he won the Nobel Prize. In 1966 he moved to the United States to work at the Institute for Biomedical Reseach in Chicago, Illinois. Unhappy with the working conditions there, he left to become a professor at the State University of New York at Buffalo from 1968 until he retired in 1975. After retirement, he moved to Switzerland and wrote on the mind-body problem. He died in 1997 in Locarno, Switzerland.

Bibliography

• How the Self Controls Its Brain
• Mind and Brain (Editor)

External links

• Sir John Eccles Biography (http://nobelprize.org/medicine/laureates/1963/eccles-bio.html). Nobel Foundation.
• Pratt, D.: John Eccles on Mind and Brain (http://www.theosophy-nw.org/theosnw/science/prat-bra.htm).
• Sabbatini, R.M.E.: Neurons and synapses. The history of its discovery IV. Chemical transmission (http://www.cerebromente.org.br/n17/history/neurons5_i.htm). Brain & Mind, 2004.