DC lesion? - a lesson?

NMF nm_fournier at ns.sympatico.ca
Tue Feb 17 01:34:23 EST 2004

Dear Peter F,

> Generally considered, there is "gating", "filtering", and *active*
> habituation$ (or repression) occurring in relation to distress motivating
> neurons' signal output, or their firing or signaling activity itself,
> whenever an animal (eg. a human individual) has ended up in a traumatizing
> situation (what I call a SHITS - for "selective Hibernation imploring type
> situation").

Clever.  SHITS  (I like that!)    (more below).

> It may be worth noting - in respect of our capability of retaining such
> situations (through neurons undergoing LTP changes that form a kind of
> partly or entirely unconscious - not consciously remembered or
recallable -
> states of SHITS-specific remembrance) - that (according to one laboratory
> report that I can remeber having read) neurons can whilst being actively
> habituated (prevented from firing) become progressively conditioned, by
> afferent signals, into a state of being "LTP'ed".

Well there has been some interesting work by Mark Bear showing sliding
modification threshold for evoking LTP and LTD, which are based on the
previous correlated firing activity of the postsynaptic neuron importance
argued from the mathematical modeling of Bienenstock-Cooper-Munroe Theory.
It seems that if you have a developing nervous system the threshold moves
towards the easy evocation of producing LTP.  As more and more connections
are gained along the entire dendritic arbor, competitive actions between
neigboring synaptic sites will compete with each other in terms of trophic
support etc.. Thus instead of getting to a point where the saturability of
LTP would occur, the converse situation emerges, that is the threshold moves
towards readily evoking LTD.  (This has been verified in monocular
deprivation studies, environmental enrichment studies, and recently studies
assesing these hypotheses in normal animals... see Mark Bear).   (more

Maybe some of Nadel and LeDoux work published in Neuron (2002?) might be
useful to look into especially with respect to mechanism.  Also K. Nadel has
an excellent paper that he published (i think 2003? or 2002) in trends in
the neurosciences, that I would definitely encourage you to read on
implications of some important physiological processes involved memory
consolidation and psychopathological disorders.  i'll find the paper and if
you want i can send you the .pdf  (Just let me know).

> Neurotic defences (a meaning more than covered by what I have
> as AEVASIVE) are an assortment of self-regulatory capacities the
> part of which is itself partly (~half) covered both by what has been
> repression and by (despite its traditionally sloppy and/or hypocritical
> definitions) "Habituation" $. (The other half of this "inhibition part",
> provided by learnt and instinctive behavioural habits or AEVASIVE focuses
> actention.)

Hmm.  That's interesting and I never thought of it quite like that.  I
personally don't believe that repression, in the psychodynamical and
Freudian sense, exists.  And I agree with you on the limitations of it's
traditionally sloppy and hypocritical definitions. Even Freud threw away the
concept of "repression" in his later work, which essentially considered it
as BS.  He later adopted the approach that it was derived by therapist and
client selective reinforcement. (the infamous "flash bulb memory" cases are
prime examples of this silliness).  However, most people do not read the
original work and as a result incorrect and Hollywood views circulate.

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