Who is the founder of twentieth century experimental neuropsychology? Lashley is given the nod, though Hebb's conception of an empirically assembled nerve net (the cell assembly, 1949) became a seminal idea in theoretical neuropsychology.
2. Further, Abeles writes, "I am still fascinated by Lashley's boldness and direct approach: - if the memory engram is located in a particular region of the brain - let us remove brain pieces until we find a place that erases memory." After a lifetime of ablation experiments, Lashley had to conclude that a specific engram does not appear to be stored in any localized part of the cerebral cortex.
3. Abeles once again: "If information is processed via long cortico-cortical connections - let us sever these by multiple cuts and find the deficit." Lashley put his postdoctoral student Sperry to work on the problem. Sperry, who later won the Nobel Prize for medicine, devised the surgical procedure but could find no deficit in motor performance or vision after the transections.
4. And finally, "... if the mass action of brain is generated by ephaptic electric fields - let us lay gold foils over the cortex and disrupt these fields." Lashley and his students Chow and Semmes failed to affect behavior with these implants. Lashley liked to say that he had disproved all theories of higher nervous function, including his own.
5. In my view, among Lashley's greatest contributions to psychological thought were his efforts first, to replace Watson's early conception of the brain as an empty black box (S - R formula) with the view that the stimulus excites the organism and it is the organism that initiates the response, as in S - O - R; second, to nudge the Gestaltists away from their speculations of electrical (DC) fields in the cerebral cortex underlying higher mental functions; and finally, to persuade the early artificial intelligence theorists to abandon their wild analogy of inert wires with living, metabolizing neurons.
6. Lashley's introduction as early as 1937 of Lorente de Nó's reverberatory circuit as a mechanism to sustain activity in the cerebral cortex set the stage for Hebb's (1949) central autonomous process and cell assembly theory. But Lashley's demonstration that synapses inactive during the learning process can still show the effects of learning ("Lashley's lesson") challenges the universality of Hebb's rule (that lasting synaptic changes constitute the memory trace in the brain) and has yet to be incorporated into modern neuropsychological theory.
Abeles, Moshe (2001) Founders of Neuropsychology - Who is Ignored? Psycoloquy: 12(026).
Hebb, D. O. (1949) The Organization of Behavior. NY: Wiley & Son.
Lashley, K. S. (1950) In Search of the Engram. Reprinted in Orbach, Jack (1998) The Neuropsychological Theories of Lashley and Hebb. MD: University Press of America.
Orbach, Jack (1998) The Neuropsychological Theories of Lashley and Hebb. MD: University Press of America.
Orbach, Jack (1999) Précis of: The Neuropsychological Theories of Lashley and Hebb. PSYCOLOQUY: 10(029).