Physical-psychological-cognitive multimorbidity: a narrative review.

Donald O. Hebb developed his cell assembly theory of neural function underlying behavior over at least 17 years, starting with his MA thesis at McGill University in 1932 and culminating in the publication of in 1949 (). There were many steps along the way, but the most important was Hebb’s application of “Lorente de Nó circuits” to his neuropsychological theory of perception and memory as these explained how a stimulus could be retained in the brain circuitry after its termination. This paper briefly summarizes Hebb’s education and academic career and then focuses on the influence of Cajal and Lorente de Nó on the development of Hebb’s neuropsychological theory. To follow this development, I have used a number of unpublished notes and papers written by Hebb between 1932 and 1947 which show the evolution of his thoughts about the “Hebb synapse,” the cell assembly and phase sequence. Portions of these unpublished papers, which are held in the McGill University Archives, are attached as supplemental files so that they are accessible to readers of this paper. Donald Olding Hebb was born in the village of Chester, Nova Scotia on 22 July 1904, the first of four children. Both of his parents were physicians, and he attended the local Chester School until the tenth grade when the family moved to Dartmouth, Nova Scotia. Hebb completed high school at the Halifax County Academy in Halifax, Nova Scotia, and in 1921, he entered Dalhousie University, majoring in English and Philosophy, with the intention of becoming a novelist (). At that time, Psychology was taught in the Philosophy Department at Dalhousie and Hebb was exposed to William James’s and Langfield and Allport’s . After graduating with his BA in 1925, he took summer classes to obtain a teaching certificate from the Provincial Normal School in Truro, Nova Scotia, and became the principal of his old school in Chester for a year (, ; ). Hebb then moved to Montreal, where he found a teaching job at Verdun High School (1927–28) and met Professor W. D. Tait, the Head of the Psychology Department at McGill University. In 1928, Hebb became a part-time graduate student in Psychology at McGill under the supervision of Professor Chester Kellogg, while by day he taught at Rushbrooke School in the Montreal suburb of Verdun, Quebec. During the 1930–31 school year, Hebb was bedridden with tuberculosis of the hip, which left him with a permanent limp. During this time, he convalesced at his father’s home in Dartmouth, Nova Scotia, and while he was bedridden, he studied
and
and wrote an MA thesis () which contains his first thoughts on the nature of synaptic activity during classical conditioning (). After the completion of his MA thesis, Hebb worked in the laboratory of Boris Babkin, a student of Pavlov, studying Pavlovian conditioning with Leonid Andreyev, who had also come from Pavlov’s laboratory to pursue his research at McGill. However, he became disillusioned with Pavlovian conditioning procedures and his graduate studies at McGill and decided to complete his PhD with Karl Lashley (, ).