"Robert J. Bradbury" <bradbury@www.aeiveos.com> writes:
> There would seem to be several requirements here:
> (a) Processing of sensory input and presumably storing the
> relevant stuff it in a short term pattern buffer
Yes. There are likely several levels of buffering, from perceptual memory (visual scratchpad, auditory loop; lasts a few seconds at most), working memory (tens of seconds) to short term memory (hours). And maybe "intermediate term memory" linked to the hippocampus.
> (b) Some application of that short term "eletrical" pattern into
> a chemico-physico structure (i.e. long term memory)
Yes. Most likely the "writing" for long term memory is synaptic rewiring. This requires gene expression and a lot of steps, so it takes time to achieve.
> (c) Some logical resolution of conflicts in the data.
Much of this is likely done when patterns fail to evoke or get into conflicts with other attractor states. During lunch our research groups speculated in the existence of "collators", the opposite of modulators, systems which gather overall information about the state of our cognition and sends it to relevant systems. One example we discussed was just conflict/contradiction detection, another recognition.
Relevance signals are also worth mentioning. Some memories should be stored, others best ignored. Emotional valence, coherence and links to other memories likely play in. This area is likely where most nootropics play in, although some like ampakines influence (a) and piracetam likely (b).
> (d) Perhaps rehersal of conclusions to strenghen the results & connections.
>
> Do you see any problem with sleeping & dreaming being the primary
> processes that allow (c) and (d) to function in the process of
> transfering data from (a) to (b)?
Not really, although I think there is more to the issue. The theory of memory consolidation I'm working on is based on the ideas of James L. McClelland and Nigel H. Goddard, who suggested that we need the intermediate buffer system to prevent overwriting of our cortical memories. Having fast learning means that you easily overwrite important information, but you need it to survive in the real world. So it is stored in the hippocampus and then used to slowly train the cortex when there is the time. This is of course also ideal for (c) and (d).
> It is interesting to consider that the sleep requirements decline
> significantly in older healthy adults. Now there could be many
> reasons for this but one would expect that they have well honed
> survival skills and have sufficiently developed their accept/reject
> pathways that most of the data gets processed very quickly.
I would rather blame age-influenced decrease in melatonin receptors. But I think your explanation is partially true, and might also relate to "the conservativism of old age" (which I also think is partially due to a dopamine deficiency... OK, I'm getting neurochauvinistic here :-)
> One possible way of testing this would be to see if sleep requirements
> increase in individuals who have traveled to a "strange" place.
I think this is true, both from personal experience (I sleep very soundly abroad or after doing something unusual during the day), and from some studies I heard about REM in chess players before, during and after a competition.
> It might be difficult to account however for decreases in sleep
> that might be caused by a higher arousal/alertness state due to
> potential dangers perceived from the environmental differences.
This can likely be factored out in a good test design.
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