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Differences between left and right amygdala....question...

maxwell mmmaxwell at hotmail.com
Mon May 21 23:45:56 EST 2001

Tony Buchanan <tony-buchanan at uiowa.edu> wrote in message news:3B098A5E.5EEF1680 at uiowa.edu...
> The neuroimaging literature is littered with findings of functional
> differences between the left and right amygdala.  One side is active in
> one task, the other during another task and with no real pattern or
> consensus as to what this functional asymmetry might mean.  The most
> intriguing new finding in this area is that of gender differences in
> amygdala activity in association with the formation of emotional
> memories.  Larry Cahill and colleagues recently published a paper in
> Neurobiology of Learning and Memory (vol. 75 pp 1-9) which illustrates
> that in women, activity in the left, but not right amygdala predicts
> subsequent memory for emotional stimuli.  The converse pattern is found
> in men (right activity predicts memory).  This finding replicates two
> previous reports of same, so this is the most consistent finding of
> human amygdala asymmetry that I know of.  Work with lesion patients
> subsequent to unilateral temporal lobectomy has shown some interesting
> patterns in this regard.  Namely, damage to the left amygdala results in
> reduced memory for emotional verbal material and damage to the right
> amygdala impairs memory for emotional pictures (as well as reducing
> visuospatial performance in general).  These studies are complicated by
> the fact that it is not only the amygdala that resected in these
> surgeries, but the temporal pole and a variable amount of temporal
> cortex as well.  I've also read of some functional asymmetries in fear
> conditioning, but I can't remember what the pattern was...
> Tony W. Buchanan
> University of Iowa

Interesting (as to laterality) what you report WRT right amygdalal lesioning, 
i.e., impairment of emotional memory. Just popping in to mention that Haxby, et al, using PET,
 observed *significant* right cingulate activity in _recognition_ phase (though not during encoding phase) of tasks of memory of human faces-- surely visual objects of emotive importance.


The article is available for free dowload at:

Haxby, J.V., Ungerleider, L.G., Horwitz, B., Maisog, J.M., Rapoport, S.I.,  
Grady, C.L. (1996) Face encoding and recognition in the human 
brain, Proc. Natl. Acad. Sci., 93:922-27.


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