Photo from the Nobel Foundation archive.
Walter Rudolf Hess
Born: 17 March 1881, Frauenfeld, Switzerland
Died: 12 August 1973, Ascona, Switzerland
Affiliation at the time of the award: University of Zurich, Zurich, Switzerland
Prize motivation: "for his discovery of the functional organization of the interbrain as a coordinator of the activities of the internal organs."
Prize share: 1/2
The diencephalon of both human and animal brains has cells that govern many behaviors. During the 1930s Walter Hess inserted a narrow metal thread into different parts of anesthetized cats' hypothalamus, an area on the underside of the diencephalon. When the cats awoke, he could trigger different behaviors with weak electrical impulses to different parts of the hypothalamus - not just simple reactions but complex behaviors. Among other things, the cats could be made to display defensive and aggressive behaviors and to curl up and go to sleep.
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