PET imaging of brain function during memorizing ?

Sean Marrett sean at petvax.mni.mcgill.ca
Thu Dec 5 16:44:54 EST 1991


In article <1991Dec5.191407.8926 at alw.nih.gov>, olds at helix.nih.gov (James L. Olds) writes:
> In article <1991Dec5.031216.7000 at thunder.mcrcim.mcgill.edu> sean at petvax.mni.mcgill.ca (Sean Marrett) writes:
> >The reference is probably to "A Functional Anatomy Study of Human Memory"
> >by Squire, Ojemann, Miezin, Petersen, Videen and Raichle.
> >
> >They used regional cerebral blood flow measured with [15-0]-H2O PET to
> >localise areas of cortical activation in a word recall/stem matching task.
> >They found activation in right hippocampal areas and right prefrontal cortex .
> >It was probably news 'cuz no one else has shown hippocampal activation in
> >a memory task.
> >
> >The reference is:
> >Squire, Ojemann, Miezin, Petersen, Videen and Raichle. Soc. Neurosci. Abstr.
> >Vol 17, Part 1, p4. 1991.
> >It was presented at the New Orleans Neuroscience meeting on Nov. 10th.
> >
> >Sean 
> 
> Hi Netters I feel obligated to respond to Sean's *error* here and point out
> that hippocampal activation in memory tasks has been reported repeatedly
> by numerous investigators from Cal Tech to NIH since 1972. For a review
> on the subject I would suggest Alkon's Scientific American piece in July
> of 1989.
> Let's try to be careful with our citations here (smile)
> Jim Olds
> NINDS NIH


Okay - mea culpa - I should have said human memory function, but then working
in PET day to day, one forgets that other experimenter's have different 
preparations. Anyway's here is the abstract in question (I hope the copyright
gods will not strike me down in my  sleep). I've emphasised the relevant
phrase. :-).  I'm sure there is a lesson to be learnt here 
but I'm not quite sure what it is. I'd be interested in some references
to other studies that have shown HUMAN hippocampal activation.
Now back to ATP sensitive K channels...

A FUNCTIONAL ANATOMICAL STUDY OF HUMAN MEMORY L. Squire, J. Ojemann,
F. Miezin, S. Petersen, T. Videen and M. Raichle. 

We studied regional cerebral blood flow using the [15-O] H2O method while
normal subjects performed  four closely similar tasks. In each task, subjects 
saw words and then saw 3-letter stems. Local blood flow was monitored during
a 40-sec period while subjects 1) silently viewed word stems; 2) completed
stems to form the first words to come to mind, but the stems could not form
study words(baseline); 3) completed stems and half of them could form study
words (priming); or 4) tried to recall study words, and half of the stems 
could form these words (memory). There were three major findings:
1) The memory task engaged the right hippocampal region (but not the 
amygdala) when the memory task was compared to either baseline or a fixation
point condition. The right hemispheric locus suggests that performance is
driven by the visual characteristics of the words rather than by semantic
or phonetic analysis. 2) Right prefrontal cortex was also activated in the 
memory minus baseline condition. 3) In the priming minus baseline comparison
, there was a reduction in blood flow in the right posterior cortex. The 
results provide the first evidence for selective activation of the human
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hippocampal region in association with memory function. The results also
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provide a specific proposal about the neural basis of priming; following
stimulis, less neural activity is required to process the same stimulus



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