A Theory of Sleep
zhil at online.no
Sat Aug 18 09:45:16 EST 2001
"yan king yin" <y.k.y@(no spam please)lycos.com> skrev i melding
news:9lkjot$om31 at imsp212.netvigator.com...
> "Brian" <zhil at online.no>:
> > "yan king yin":
> > > Some neurites undergo maturation in the cytoskeleton and also
> > > After that their structure is much more stabilized, and it seems that
> > > process is irreversible. Maybe the brain is modular so that some
> > > retain plasticity while others are more stable.
> > Thanks for the reply.
> > Your last point about plasticity of the neurites, question - are there
> > papers about which neurites remain the plasticity and those that
> I dont know what causes some axons to be myelinated and others not.
> A study by Francine Benes says:
> "Myelination levels kept rising into the early twenties, she found, and
> flattened out after having doubled in the second decade of life. But
> took off again in the forties and continued into the mid fifties,
> average, another increase of 50 percent before leveling off again."
> I dont know what to make of it.. it doesnt correlate very well with
> learning and cognitive abilities.
Sounds like the brain is consolidating itself to me,making it more
The the brain developes through apoptosis (programmed cell-death) from
course depending of it's usage.
But the downside is of course the danger of reducing the numbers to much, to
make it more vulnerable and dependant on each cell.
> Also I found this review in PubMed:
> Neurol Neurochir Pol 2000;34(3 Suppl):41-4 Related Articles, Books
> [Pivotal role of axonal adhesion molecules in central nervous system
> [Article in Polish] Lubetzki C, Charles P, Stankoff B, Hernandez P, Zalc
> In the abstract it says that "blocking or stimulating electrical activity
> inhibit or induce myelination respectively".
> I speculated that some neurons might retain plasticity because different
> neurotransmitter receptor subtypes are expressed in different regions of
> the brain, and the hippocampus is more strongly associated with various
> forms of amnesia (eg failure to form new memories) than other brain
> regions, and its lesion does not cause loss of early memory. This is cited
> as evidence that the hippocampus consolidates memory but does not
> store it. But according to the selectionist perspective, memory should be
> distributed in all brain regions. This is very perplexing...
Hmm, that is longterm memory, but short-time memory goes through the
selective attention system (Thalamus) and then through Hippocampus.
I wonder if attention is directly connected to short-time memory, and that
somehow stimulates myelination......
But what perplexes me are those changes of levels in myelination you
Anyway, correct me if I'm mistaken - "Conversations vith Neils Brain" is
good, but there are more to it I suspect.
> > By the way, I logged onto your homepage and there was a picture of a
> > was that you ? (He seemed to say "Hey you!")
> It was me last summer visiting London, i'll update it soon =)
As if it not comprehensible from before :)
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