[Original response, as documented elsewhere.]
I do not know. At the level of ionic conductances, and to the degree that such
enter into activation-dependent trophic responses, it makes no difference with
respect to what I posted, does it? ken
to which I'll add, here:
On a whim, stopped in the college lib up the street and picked up the 1st 4 issues
of _Science_ in the pile... the 2nd had neurons on the cover, so I checked the toc
and found this:
see _Science_, 9Jan98, p227 (related comments p191): "Sensitivity of CaM Kinase II
to the Frequency of Ca(2+) Oscillations", by P. De Poninck and H. Schulmas [dept
of Neurology Stanford Med.]... LTP is a factor in these activity-dependent,
information-carrying dynamics... and my comments, above, apply... and there is a
major subset within the set of all AD that's non-familial.
Although it's not its main point, another article in the same issue of _Science_
your Q concisely: _Science_, 9Jan98, "Frameshift Mutants of B Amyloid Precursor
Protein and Ubiquitin-B in Alzheimer's and Down Patients", by F. W. van Leeuwen,
et. al., p242 (related discussion p174)... "In Alzheimer's disease (AD) and Down
syndrome (DS) patients, intracellular and extracellular deposits if proteins in
tangles are correlated with neuronal dysfunction leading to dementia(cites R. D.
Terry, Et. Al. in _Alzheimer Disease_, R. D. Terry, et. al. Ed., Raven, NY, 1994,
Again, I work at a fundamental level, integrating Foundation Stuff... I don't
study pathology with an eye to explaining it... but if I were studying patholgy,
after reading the De Koninck article, I'd feel Obliged to take the LTP thing the
whole nine yards.
[BTW, I do not read in the stacks much anymore... not because I do not want to,
but because its been the case for about 15 years that I can't pick up anything
without witnissing a flood that needs to be dealt with with respect to it... the
reading is too painful... folks who view the stacks as dust-receptacles don't like
such disturbed... it's a Sorrow to see how "scientists" actually feel about what
should be their Beauty.] ken
Walter Eric Johnson wrote:
>kkollins at pop3.concentric.net wrote:
> : [snip]
> : > Alzheimer's disease is characterized by progressive dementia and a
> : > characteristic neuropathology - the appearance of large numbers of
> : > senile placques and neurofibrillary tangles.
> : [snip]
> : I've studied the wholely-functional nervous system, and I've not
> : specifically studied Alsheimer's, nor its organic-damage correlates, so take
> : what's here "with a grain of salt".
> : "Ttangled" neural growth does correlate well with a condition in which
> : neural activation "states" have been enduringly-relatively-random. This's is
> : because, since neural trophy occurs as a function of activation, if the
> : activation is relatively-disordered, the activation-dependent growth will
> : reflect the randomness of the activation... this'd yield "tangles"... growth
> : that follows a "random walk", and all manner of abnormal dynamics could
> : cause such, including desynchronization within what would, otherwise, be LTP
> : "states".
>> I thought the neurofibrillary tangles were of neurofilaments within a
> cell and not tangles of neurons themselves. Did I misunderstand this?
>> Eric Johnson