Re: New Scientist on memory

Date: Sun 01 Jun 2003 - 18:37:44 GMT

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    > > From:
    > > > >
    > > > > > Though the author himself doesn't seem to realize it, the
    > > > > > evidence discussed in this article abolishes the notion that
    > > > > > the brain alone is responsible for memory. Every time we
    > > > > > recall something, the relevant memory trace in the brain is
    > > > > > completely erased and then "reconstituted" from scratch. If
    > > > > > memory is nothing more than stored information in the brain,
    > > > > > there would be no way of recreating the memory once it's been
    > > > > > erased. The only explanation is that we literally recall the
    > > > > > past (often making mistakes in the process) enabling us to
    > > > > > reconstruct the memory after the neural trace has been
    > > > > > destroyed. Memory must be taken at face value-- as a
    > > > > > recollection of the past-- rather than simply the retrieval of
    > > > > > information from cerebral vaults. We may regard neural traces
    > > > > > as pointers to memories rather than the memories themselves.
    > > > > >
    > > > > > --TD
    > > > > >
    > > > > The article states that memory is not 'erased' so much as it is
    > > > > 'redynamized';
    > > >
    > > > Every time you remember something, the relevant "memory trace" in
    > > > your brain is erased. Ordinarily, you simply re-establish the
    > > > trace, perhaps in modified form, in the act of recalling the event
    > > > from the past. But if something interferes with your ability to
    > > > re-establish the trace, such as a drug that stops
    > > > protein-synthesis, you lose the memory. The trace, which had
    > > > already been erased, is now gone for good. It's in the gap
    > > > between recall, when the neural trace has been liquidated, and the
    > > > moment the trace is re-established, that the true nature of memory
    > > > is revealed. During that gap, your brain cannot help you
    > > > remember. It's up to you.
    > > >
    > > The memory is not erased, it is simply 'fluidified', that is,
    > > 'unfixed'
    > from
    > > its memory storage moorings. But it is still there during the
    > > active remembrance. It must be 'refixed' if it is to remain, and
    > > that usually happens by the very act of remembrance. However, this
    > > 'refixing' process can be interdicted by certain drugs. In this
    > > case, the 'unfixed' memory simply dissipates, thatis, it is
    > > forgotten, rather than being 'refixed' in memory storage.
    > When a memory is recalled, it must be "fixed" or forgotten. If lack
    > of protein prevents "reconstitution," the memory is gone. If there
    > were a backup-- a copy of the memory before it was recalled-- why
    > would it be erased at the very moment the attempt to re-fix it fails?
    > This doesn't make any sense. Clearly, the original memory trace is
    > gone from the very moment the memory is recalled, but this absence is
    > revealed only when reconstitution fails. Once the memory trace
    > becomes "fluid," it no longer has the structure that made it a memory
    > trace. There is thus no backup, no piece of the old memory we can
    > revert to once the new version fails. There's simply nothing.
    > This is what's so shocking and why some researchers, such as Cahill at
    > UC Irvine, refuse to believe it despite numerous replications of this
    > experiment on several species of animals. The new finding throws the
    > whole field into turmoil. What this means is that there is no memory
    > trace during the crucial period when the memory is being
    > reconstituted. All during the "fixing" process, nothing physically
    > guides the way. We remember on the basis of nothing-- at least
    > nothing in the brain. How could this be? For memory research this is
    > the end of the world as we know it.
    > Why is it that highly evolved creatures have no method of retaining
    > memories in the event that reconstitution fails? Why hasn't the
    > environment selected for animals that won't lose important memories
    > just because they lack sufficient protein when memories are called up?
    > If we're going to tamper with a memory, and the tampering could
    > easily go wrong, why not make a backup copy? But then, if the memory
    > doesn't consist of stored information in the first place, how could it
    > be copied?
    > The brain does not contain records of memories but mere "traces" that
    > point us to them. A trace can be wiped clean at the moment we
    > remember it because, now that we recall it, we don't need the trace
    > anymore. But we'll need it the next time we want to recall it. So
    > the trace is re-fixed. But if the fix isn't carried out, there's
    > nothing left, no "dynamized" or "fluidified" or "unmoored" relic.
    > Simply nothing.
    No, a memory that has been accessed is still in the brain, it is just in the realm of attention rather than being stored. If it is not chemically blocked from doing so, the very act of reaccessing it causes the axons, dendrites and synapses, through the electrical-stimulation-induced production of the MAP-2 protein, to strengthen their myelin sheaths, increasing the fixation of the memory pattern and therefor reinforcing the memory.
    > > From: Lawrence DeBivort (
    > >
    > > Dace, '"reconstituted" from scratch' sounds like an unmitigated
    > contradiction
    > > in terms to me. Can you explain how it isn't?
    > It is a contradiction, Lawry. You can't reconstitute something from
    > nothing, and there's nothing in the brain that could provide the model
    > for reconstituting a memory trace once the memory is recalled.
    > Therefore reconstitution of the memory trace proceeds through active
    > recollection of the past. Without true memory, a trace would indeed
    > have to be reconstituted from scratch-- an impossibility.
    Once again, Dace attempts to sneak his pet Sheldrakean 'morphic resonance' magickal mystical Einsteinian-spacetime-denying woo-woo in through yet another back door he mistakenly thinks he has discovered. But doors leading the serious and ungullible to such pseudoscientific and nonsensical absurdities just ain't there.
    > Ted
    > ===============================================================
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    > Journal of Memetics - Evolutionary Models of Information Transmission
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