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PTSD memory sites?

F. Frank LeFever flefever at ix.netcom.com
Tue Mar 23 21:46:49 EST 1999


Unfortunately, my browser cannot retrieve my original response to  this
query, only my follow-up to that response.  If YOU can retrieve it,
please read my discussion of the problem of locating ANY memory,
repressed or expressed., and my discussion of the relevance of LeDoux's
work, which provides a model for primitive conditioning of emotional
responses and thus for re-instatement of emotional responses to the
original trauma, with no need for "repression" (i.e. no well-developed
contextual memory to repress).

To the extent that there is some lateralization for other aspects of
memory (e.g. right lesions impairing memory for certain kinds of visual
nformation), and some lateralization for emotional activity, your
conjecture is reasonable.

LeDoux has examined in detail the neural pathways for various aspects
conditioned emotional responses (motoric, autonomic, etc.), but so far
as I know has done so in terms of rostral-caudal directions,
connections between specific structures within a hemisphere, etc., and
has not looked at laterality.

I may have a chance to ask him about it, this Saturday--I'll be
attending NYU's celebration of "A Century of Psychology at NYU" (as one
of the Psych Department's several thousand Ph.D. alumni).

There may already be SPECT studies of PTSD patients, relevant to 
questions of which areas are chronically increased/decreased compared
to controol subjects.  For the kind of study you are thinking of, a
less invasive technique, MEG, would allow localization in "real time",
i.e., moment to moment mapping of activity--e.g. while subjects are
presented with stimuli associated with their traumatic experiences.

Might not be too hard to get approval, informed consent, etc., if
experimenters are prepared to limit/treat the expected reactions, and
if used in the context of a behavior therapy procedure to desensitize
patients to these stimuli... 

F. Frank LeFever, Ph.D.
New York Neuropsychology Group


In <SPR990323110021-17339 at kauri.vuw.ac.nz> George <sawdust at sccoast.net>
writes: 
>
>Now before I get 'flamed', here remember that you are dealing with the
>delicate psych
>of an undergrad. . . LOL
>Starting with the though that there is a hemispheric division of
'labor' and
>activities
>in the brain, I wondered if trauma associated memories might be
'stored' in
>one side or the other.
>Since the right hemisphere exhibits superiority in nonverbal emotional
>expression, that is where I would expect to find such memories
located.  If
>in fact this was the case, it might be related to the 'hyper'
vigilance of
>surroundings experienced by PTSD clients, and also might begin to
unravel the
>mystery of the success of EMDR treatments in some PTSD cases; (my
thought
>there relating to better hemispheric communication via the corpus
callosum)
>
>I would think that examination of such memories could be accomplished
by
>placing a PTSD client
>in a PET scan, and drawing out said memories with the aid of a
therapist.
>Yes, I am aware of the ethical issues involved, and aware that this
research
>probably would not happen today because of said ethics.
>
>Nancy Stone wrote:
>
>> Daniel Schacter at Harvard is using imaging to study false memories.
>> That's not the same as repressed memories.  Is there some reason why
>> you believe that repressed memories wouldn't be located in the same
>> place as unrepressed memories?  Since most imaging shows brain
>> activity, how would you demonstrate a lack of activity for something
>> that is not being recalled?  Are you perhaps talking about imaging
the
>> mental effort involved in suppressing a memory (see Wegner)?  Or are
>> you referring to what occurs when someone recalls something
previously
>> repressed but now recallable?  Joe LeDoux's book "The Emotional
Brain"
>> discusses areas of the brain involved in memory, emotion, and
stress,
>> though I don't believe he is using imaging it might have some useful
>> references.
>>
>> Nancy
>
>--
>
>'`'`'`'`'`'`'`'`'`'`'`'`'`''`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'
'`
>            sci.psychology.research is a moderated newsgroup.  
>Before submitting an article, please read the guidelines which are
posted 
>here bimonthly or the charter on the web at http://www.grohol.com/spr/
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--

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            sci.psychology.research is a moderated newsgroup.  
Before submitting an article, please read the guidelines which are posted 
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               Submissions are acknowledged automatically.



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