The influence of Cajal and Lorente de Nó on Donald O. Hebb's neuropsychological theory

Donald O. Hebb was born in Chester Nova Scotia on 22 July 1904, attended the Chester school and the Halifax County Academy, and obtained a BA in English and Philosophy from Dalhousie University in 1925. After obtaining a teacher's certificate he taught in his old school in Chester for a year and then in Montreal while attending McGill University to obtain his MA in Psychology as a part-time student. He moved to Chicago to work with Karl Lashley and then completed his PhD with Lashley at Harvard in 1936. He was an instructor for a year at Harvard (1936-37) and then received a Fellowship to work at the Montreal Neurological Institute (1937-39), conducting neuropsychological tests on the patients of Dr. Wilder Penfield. From 1939 to 1942 he was a professor at Queen's University in Kingston, Ontario and then a Research Associate of Professor Lashley, studying emotionality in chimpanzees at the Yerkes Primate Center in Florida (1942-1947). It was there that he began to write his influential book, The Organization of Behavior. This book introduced the concepts of synaptic change, cell assemblies, and phase sequences to account for the neural events underlying behavior. Hebb's work revolutionized the study of brain and behavior by establishing a biological basis for psychological phenomena. Hebb became a professor of Psychology at McGill University in 1947 and head of this department in 1948, completing his book at McGill in 1949. The crucial element in Hebb's theory was the concept of reverberatory circuits of Lorente de Nó, based on Cajal's concept of closed circuits. This paper examines the unpublished notes and papers written by Hebb between 1932 and 1947 as he developed his theory of neuropsychological function based on the concept of closed or reverberatory circuits and how this theory was used in psychology, neuroscience and the computer modeling of brain functions.