<P> The theoretical underpinnings of Moniz's psychosurgery were largely commensurate with the nineteenth century ones that had informed Burckhardt's decision to excise matter from the brains of his patients . Although in his later writings Moniz referenced both the neuron theory of Ramón y Cajal and the conditioned reflex of Ivan Pavlov, in essence he simply interpreted this new neurological research in terms of the old psychological theory of associationism . He differed significantly from Burckhardt, however in that he did not think there was any organic pathology in the brains of the mentally ill, but rather that their neural pathways were caught in fixed and destructive circuits leading to "predominant, obsessive ideas ." As Moniz wrote in 1936: </P> <P> (The) mental troubles must have...a relation with the formation of cellulo - connective groupings, which become more or less fixed . The cellular bodies may remain altogether normal, their cylinders will not have any anatomical alterations; but their multiple liaisons, very variable in normal people, may have arrangements more or less fixed, which will have a relation with persistent ideas and deliria in certain morbid psychic states . </P> <P> For Moniz, "to cure these patients," it was necessary to "destroy the more or less fixed arrangements of cellular connections that exist in the brain, and particularly those which are related to the frontal lobes," thus removing their fixed pathological brain circuits . Moniz believed the brain would functionally adapt to such injury . A significant advantage of this approach was that, unlike the position adopted by Burckhardt, it was unfalsifiable according to the knowledge and technology of the time as the absence of a known correlation between physical brain pathology and mental illness could not disprove his thesis . </P> <P> Egas Moniz (1937) </P>

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