Herbert Spencer Gasser ( 5 July , 1888 - 11 May , 1963 ) was an American doctor . He won the 1944 Nobel Prize in Physiology or Medicine , along with Joseph Erlanger , for discovering the many functions of a single nerve fiber . Herbert Spencer Gasser ( July 5 , 1888 -- May 11 , 1963 ) was an American physiologist , and recipient of the Nobel Prize for Physiology or Medicine in 1944 for his work with action potentials in nerve fibers while on the faculty of Washington University in St. Louis , awarded jointly with Joseph Erlanger .