EEG: brainwave generation, questions
rcb1 at LEX.LCCC.EDU
Mon Feb 5 09:20:23 EST 1996
On 2 Feb 1996, Friso Westerhuis wrote:
> (Hypnotics) wrote:
> >Also, it seems accepted that brainwaves can be broken down into their
> >component sine waves by fourier transform, but what evidence is there that
> >brainwaves ARE sinusoidal? What evidence shows that brainwaves cannot
> >REALLY be sawtooth in some instances, square in others etc. Are we
> >creating an artificial construct?
No, our concentration on neurotransmitters have blinded us to not seeing
that neurotransmitter/frequency/temporal relationship are the keys to
neuroprocessing. This is an understandable error considering the
historical development of our knowledge. Five years ago, I would have
said you were nuts for thinking such a relationship.
> The Fourier transformation is "just" a mathematical procedure to
> transform the signal from time domain (an EEG for example) into the
> frequency domain (the spectrum). It can be demonstrated that almost any
> function can be described by a set of sines and cosines. So the use of
> cosines and sines doesn't say a thing about the physiology.
It says alot about physiology but not in a way that will generate
easy data. The evolution of the physiology makes sense to me now.
Microtubules were the tranport mechanism which is likely to sensitive to
electrical osscilations. Modulations resulted in neurotransmitters tuned
to the modulation. Cells picked up the neurotransmitters and forwarded
the message. Self organization results due to correlational opponent
process. Self organization is very sensitive to the environment resulted
in learning. Learning lead to us. Ron Blue
> These functions are special because they are periodic and orthogonal.
> Other functions like blockwaves for exapample could also be used to
> descride a function (or a signal like an EEG).
> So this transformation, by using cosines and sines does not say anything
> about the generation of an EEG. It's useful though, because the spectrum
> (the "product" of an Fourier Transform (FFT) ) contains useful
> information about the (generation of the) EEG.
> A very good book about this subject is :
> Paul A. Lynn
> An Introduction to the Analysis of Signals and Processing of signals
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