In <009001bdfbc6$9f4c0e20$2b242499 at default> rcb5 at MSN.COM ("RonBlue")
>> Conditions which impair LTP seem to
>>impair learning and long-term memory. Accordingly, many pathologies
>>which involve impaired memory might be based on interference with
>>initiation or maintenance of LTP--but many others might not be.
>Consider this interesting fact. If a child in the mild of winter
>falls into a ice pond and dies. We can take him or her to the
>and revive them. There memory before falling in is still intact.
>that memory is like a filter interacting with future stimuli.
One has to distinguish (or one SHOULD distinguish) between various
senses of the everyday speech term "memory", particulary between recall
of an already formed memory and the process of forming a memory.
Well consolidated memories are very resistant to disruption or
"erasure". However, consolidation is a matter of degree, and the
process can continue longer than one might think reasonable. One
outcome of this is that there can be a gradient of retroactive memory
loss following some brain insult, such as events just before the insult
are missing from memory, with more and more memory intact for events
earlier and earlier.
If you mean memory for most of what the knew before drowning is intact,
yes; but what of the moments just before drowning? The usual impact of
trauma/anoxia, etc. on memory consolidation of recent events may be
reduced somewhat because of the sharply decreased metabolism during
hypothermia (there are also circulatory reflexes based on face-wetting
which are prootective, I believe). Indeed, artificial cooling is
under study as a means of reducing damage due to mechanical trauma (at
the level of excitotoxic reactions, ischemia, anoxia due to respiratory
or cardiac arrest, and mechanical trauma are all quite similar).
No doubt our past experience filters all future inputs, but I fail to
see what this has to with the example you cite.
re LTP and Alzheimer's: LTP is just one of MANY neural activities which
may be impaired in Alzheimer's, but just because both have to do very
loosely with "memory" that does not mean that LTP is of central
importance in Alzheimer's.
F. Frank LeFever, Ph.D.
New York Neuropsychology Group