John Eccles (neurophysiologist)

Sir John Carew Eccles AC ( born January 27, 1903 in Melbourne, † 2 May 1997 Locarno ) was an Australian physiologist and Nobel Prize winner. With his research on signal transduction of neurons, he contributed greatly to elucidate the processes in the human brain. For this research he received along with two colleagues in 1963 the Nobel Prize for Medicine and Physiology.

Life and work

John Carew Eccles was born in 1903 as the son of teacher couple William James and Mary Eccles Eccles (born Carew ) in Melbourne. He studied medicine at the University of Melbourne and graduated from there in 1925. At Oxford University, he continued his studies. He conducted research there from 1927 to 1931 at the Department of the physiologist Charles Sherrington Scott ( 1857-1952 ) over the course of reflections and signal transmission across the synaptic cleft and published during this time, together with Sherrington eight scientific articles. 1929 Eccles received the Doctor of Philosophy. Until 1937 he remained in various positions in Oxford.

From 1937 to 1966 worked and taught Eccles at the University of Otago and the Australian National University. After that, he conducted research at the American Medical Association Institute for Biomedical Research in Chicago on biomedical issues. In 1968, Eccles faculty member at the College of the University at Buffalo, The State University of New York. In 1961 he was elected a member of the Leopoldina.

During his work in Oxford Eccles discovered in 1951 along with his colleague, the British physiologists, Alan Lloyd Hodgkin ( 1914-1998 ) and Andrew Fielding Huxley ( 1917-2012 ), the electro- physiological mechanism of postsynaptic inhibition of impulse conduction: The cell on the extension of the motor neuron ( motoneuron ) incoming pulse causes excitation or inhibition, as will be distributed to the nerve fiber endings, synapses, excitatory or inhibitory chemical substances that transmitter substances called. Thus, the electrical impulse transmission between nerve cells was elucidated at the synapses. For this work, Eccles received together with Hodgkin and Huxley in 1963 the Nobel Prize for Medicine and Physiology. In the grounds of the Nobel Committee stated: " For their discovery concerning the ionic mechanism that takes place at the excitation and inhibition in the peripheral and central portions of the nerve cell membrane. "

The estate of Eccles is located at the " Institute for the History of Medicine " in Dusseldorf.

Scientific work

After reading Charles Scott Sherrington's Integrative Action of the book The Nervous System Oxford Eccles had deliberately chosen as the first stop of his research career to participate in the laboratory can Sherrington. When he received the Nobel Prize in 1932, Eccles was involved in the publication of the book Reflex Activity of the Spinal Cord in the Sherrington Group gave an overview of their studies of the past decade. Another leading figures with significant influence on his research Eccles mentioned in his 1964 book The Physiology of Synapses Santiago Ramón y Cajal and Henry Hallett Dale.

The first phase Eccles ' research was how the action potentials across the synaptic cleft of time to be forwarded. For a long time stood on this issue two theories opposite: while the one that, among other things inspired by Sherrington, assumed that chemical messengers play a central role at the synapses, held the other a direct electrical transmission more likely. Eccles hung on a long time of electrical theory and collected in his experiments, data to support this. After hearing a philosophy of science Karl Popper's lecture series in May 1945, Eccles began to formulate his theories increasingly sharper and propose experiments to their falsification.

However, he interpreted his following studies initially still in full accordance with the predictions of the theory of an electrical impulse conduction. In 1949 he had to modify this but for the first time and now admitted a chemical mediation at the neuromuscular junction. After he had succeeded with colleagues in his laboratory in Dunedin, carry potential measurements in single cells of living animals, he found in 1951 at an inhibitory synapse, a potential whose sign was contrary to his theory. Although Eccles had been one of the sharpest critics of the theory of chemical mediation, he had his own theory can thus refute the first clear and accepted the validity of the chemical transmission now available to the central nervous system.

Philosophical position

Eccles also dealt with the philosophical problem of consciousness. For him, it was clear that only humans possess a " self-awareness ". This was created by procreation to the people and develop through the relationship with the outside world in the first years of life. Eccles rejected a strict materialism, ie the position, let the consciousness be reduced to purely physical and chemical processes, from. He likened about the brain with a computer and the "I" with the programmer. His idea of ​​the interaction between the brain and intangible awareness presented Eccles in the 1970s together with the philosopher Karl Popper in the book The Self and Its Brain ago ( German: The Self and Its Brain ). He referred back to Popper's three-world theory, claiming that there are certain regions in the left hemisphere of the brain associated with the mental " World 2 " enabled the interaction of the material " world 1".

Conjecture how this interaction could take place, Eccles presented only in old age, inspired by ideas of the German physicist and philosopher Henry Margenau. He postulated that the smallest processes at the level of quantum physics are enough to affect the release of neurotransmitters and concluded that the effect of an energy-and mass-less mind to the brain thus will be explained by an influence of the quantum mechanical probability fields. Critics point out that this proposal is the explanation problem of interactionism only was shifting, since now the type of interaction between mind and probability field is unclear. Despite an enormous respect for his scientific life's work is Eccles ' position to the mind-body problem, from which he derived also hope for a life after death, today mostly regarded as implausible and seen as an example of how much the thinking of many brain researchers religious beliefs and is marked by a interactionist dualism in the sense of René Descartes.

Writings

• The Physiology of Synapses. Berlin 1964.
• Karl Popper: The Self and Its Brain. Munich 1982, ISBN 3-492-21096-1.
• How the self controls its brain. Berlin 1994.
• The evolution of the brain - the creation of the self. Munich 2002, ISBN 3-492-23709-6.

More Awards

In 1962, the Royal Medal of the Royal Society awarded him.