ANOTHER STRIKE AGAINST EQUIPOTENTIALITY IN THE BRAIN.
A Critique of Amygdala activity related to enhanced memory for pleasant and aversive stimuli.
Hamann, S.B., Ely, T.D., Grafton, S.T., & Kilts, C.D. Amygdala activity related to enhanced memory for pleasant and aversive stimuli. Nature Neuroscience, 2(3): 289-293.
Never has a theory in brain research been as incorrect as the theory of equipotentialism, initiated in the early 17th century. The debate between localism and holism in the brain brought forth great thinkers such as Paul Broca and Jean-Baptiste Bouillaud who bolstered the localism argument, and Marie-Jean-Pierre Flourens who argued for holism or equipontiality. It was during this debate that Broca first concluded upon the lateralization of language in the left hemisphere. The investigation of localization of language in a brain disproving the holistic qualities of the brain was the first of a multitude of evidence that refuted equipotentiality as an applicable theory n the brain. Consistent with this legacy is research completed by Hamann et al. (1999), which further localizes brain function in the temporal lobes of a structure called the amygadala. Temporal lobes have been linked to memory via studies of amnesic subjects with damage to this structure, but there was an important dissociation made by Cahill and McGaugh as they studied a patient with amygdala damage and found that he remembered non-emotional aspects of a story normally but in contrast to healthy subjects, failed to show enhanced memory for emotional parts of the story. This finding allowed for researchers to dissociate amygdala function from the overall deleterious memory effects elicited by global temporal lobe damage. These dissociations allowed neuropsychologists such as Daniel Schacter to vehemently conclude that damage to the amygdala alone does not produce a serious impairment in recognition memory but instead causes a major deficit in memory for emotional experiences (Schacter, 1996).