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Deja vu

David B. Held dheld at uswest.net
Sun Feb 28 15:19:51 EST 1999


Hmm...

    The comments have all been very interesting and helpful, but it
seems to me that the most insightful comments I have seen thus far came
by mail from a certain Mr. Ron Blue.  I'm not sure what his credentials
are, and I didn't entirely follow his explanation, but I was wondering
if some of the neurophysiologists here could comment (hoping Ron doesn't
mind).

Ron wrote:

> You can make anyone experience déjà vu by modulat[ing] a magnetic
> field over the right temporal lobe.

    Since changing magnetic fields induce changing electric fields, I
suppose you could directly stimulate brain activity in this way; but I
have never had bizzarre mental experiences standing next to large
loudspeakers in operation.  Do people report strange psychological
phenomena while being subjected to an MRI?

> This suggest[s] that the brain is using time references for data
> analysis.  I do not remember the frequency, but as a guess it was
> around 15 hertz. Randomly, since you are a limited inferior
> biochemical computer, time phase errors occur.  Data goes into short
> term memory but is not strong enough to generate a conscious phase
> lock for that information.  The data comes in again slight[ly] out of
> time phase and you have the conscious experience of both. One as a
> subharmonic of the main gaussian wavelet stimulation and the memory
> opponent wavelet.

    This where things get a little fuzzy.  I seem to have a vague notion
of what Ron is saying here, but I don't know enough about phase locked
loops and the temporal aspects of cognitive processing to know if this
is a plausible explanation.  It sounds like there is a "time signal"
that exists somewhere in the brain, and that it correlates sensory
events with a timeline.  It seems further that if data from an event
gets processed at the wrong phase of the time signal, that the brain
will interpret this as occurring at a very different time from the data
currently in STM.  Thus, as the new data interacts with the remainder of
the old data, the temporal processing regions interpret this as a
"memory", instead of as more of the same experience coming in. Is this a
fair understanding of your explanation, Ron?

> With a wavelet system only small pieces of match up are necessary to
> stimulate a whole memory.  Technically speaking the memory can be a
> composite or creative memory suggesting a feeling of precognition,
> when in fact our memor[ies] are remarkabl[y] good.   For example, our
> visual memory is very good even 70 years later.  Locations are similar 
> enough to stimulate a holographic memory from the past which could be
> interpreted as déjà vu.

    I thought it was the autoassociative properties of neural networks
that allowed partial information to stimulate a whole memory.  I guess I
don't understand exactly what a wavelet model of cognitive processing
looks like.

> About 98% of the people experience déjà vu.  It is the experience of
> déjà vu that convinces the average person that ESP phenomen[a] [are]
> real and should be investigated by psychologist[s].   About 89% of
> the psychologist[s] checking out déjà vu as a ESP phenomenon report
> that the effort is a waste of [their] time and [that] there is NOTHING 
> important to the déjà vu phenomenon.
> 
> Actually the reports can be interpreted as supporting a more global
> model of how the brain works.  Namely a wavelet associational
> reciprocal inhibition, or correlational opponent processing model of
> how the brain works.

    Could you elaborate on this, Ron?  I have some idea of what wavelets
are from a mathematical perspective, and how they are used to compress
image data; but I don't know enough about signal processing and such to
see how they apply to the brain.
    If some of the neurophysiologists could comment on neural
stimulation by modulation of a magnetic field and give a brief
explanation of how the brain processes the temporal aspects of sensory
input, I would appreciate it.  This has all become rather intersting, if
I may say so!

Dave



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