> We now know that when one synapse undergoes LTP it spreads out to
> other synapses (the LTP signal is sent by the diffusion of nitric
> oxide). This means there must be a large amount of redundancy in
> the storage mechanism of memory and that could help a lot if we
> want to repair a badly damaged frozen brain.
It should be noted that this is not certain (John and I have
disagreed on this for ages :-); most studies of the spread of LTP
have been done using hippocampus slices in vitro, and these results
may not hold in vivo (for example, one study I heard about showed
very different results when done at 21 centigrades than when done at
37 degrees). One idea several neuroscientists discussed at a
symposium I visited was that the NO diffuses "a long way", but that
to achieve LTP you need other factors in the synapse; the spreading
out of LTP observed could be due to synchronous firing (due to the
artificial stimulation) of the other synapses.
I think we'll get our answers sooner or later, there is a lot of
interesting research going on in this field (and there are other
substances beside NO, like CO, that could act here).
-----------------------------------------------------------------------
Anders Sandberg Towards Ascension!
nv91-asa@nada.kth.se http://www.nada.kth.se/~nv91-asa/main.html
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y