On 23 Jan 1995 23:11:08 -0500,
Thomas R. Gregg <greggt at strauss.udel.edu> wrote:
> <jwwilliams at gems.vcu.edu> wrote:
>>Those of us who deal with the brain and thought are at the same impass. We
>>cannot explain how its working using 16th century physics. The paradigm must
>>change but science need not be abandon.
> ^^^ ^^^^^^^ ^^^^ ^^^ ^^ ^^^^^^^
>I'm glad to hear you say that.
>>>As per the discussion: Paul Werbos recently presented a model showing that it
>>takes 20 neurons to process one bit of information. (I don't know who
>>developed it or if its been submitted for critical review). One bit, for
>>instance, being one color. If we look at one landscape imagine the bits of
>>information that must be processes instantaneously,
>>This ratio of "20 neurons to 1 bit" is misleading. A bit is a one or a
>zero. Neurons fire APs, lasting about 1 ms. These APs could possibly be
>considered a "bit" of one. Let us say that the average neuron can fire at
>200 Hz. Then it is capable of processing 200 bits per second. If there
>are a billion neurons in the cerebral cortex, this is comparable to a
>32-bit microprocessor with a 6250 MHz speed. The new Pentiums have 90 MHz
>speed.
>>However, this does not give the brain enough credit, because the
>combinations of neurotransmitter and synapses, and connections between
>neurons, must raise the "processing capacity of the brain" exponentially.
>>Neurons also release neurotransmitter, and some of them (in the retina)
>pass analog voltage changes along to other neurons without converting them
>to the "digital" APs.
>>Remember that attention filters out most details from consciousness.
>Thus while, yes, some brain areas must process those stimuli, association
>cortical areas do not have to process sensory information all the time.
>>>numerous colors, shades,
>>hues, shapes, distances, the movement of things, smells...on and on. When we
>>still need neural circuits to maintain motor and visceral function, where is
>>all this being processed?
>>See a biopsychology textbook.
>>>Where thought is taking place is an excellent question.
>>But where is any of this taking place.
>>....
>>>broken up into energy packets. It all moves into what Einstein caled the
>>void. His frustration about relativity was that E=MC2 was intrepreted as
>>energy comes from matter. His focus was the opposite. Energy it the primal
>>source of everything. Energy makes up our mass. We only perceive mass.
>>The
>>only way we know what is around us is through perception and the brain does
>>not have the ability to process all this.
>>You haven't provided very strong evidence for this statement.
>>>So, in conclusion, if the brain does not have the capacity to process
>>everything
>>I think you mean that the brain does not have enough capacity to account
>for our experience of perception and thought. Even if this is right,
>you should provide a reasonable alternative to the idea that the brain is
>the thing that thinks. If not the brain, then what?
>>>and this matter that makes up our world, bodies and brain is only
>>an electromagnetic illusion,
>>what the heck are we.
>>E=mc^2 does not imply that mass does not exist. For the purposes of this
>discussion, I think we can assume that both mass and energy are real.
>>>Where it this thought?
>>What is this thought?
>>We are at a point where these questions cannot be
>>ignored. If we do we will never understand brain function.
>>The "where is this thought?" question is interesting. Does it exist in
>my mind, your mind, or on the computer screen?
>"What is this thought?" is even more difficult to answer. However, I
>think of "brain function" as being manifested in observable behavior. So
>from my perspective, for example, the function of motor cortex is to help
>initiate movements. The function of visual cortex is to help decode the
>meanings (i.e., relevance to reproductive fitness) of visual stimuli. We
>can understand these functions of brain areas without asking questions
>like "what is a thought?" We can understand much of brain function while
>ignoring questions like those.
>--
>Tom
Since physicists have been dragged into this debate I think it is relevant
to point out that physics is the study of things that can be measured. If
a process, such as thought, cannot be measured it exists outside the realm
of physics, at least until some measure is found. Most likely belonging to
the field of philosophy. Thus, applying the formulations of physics to
questions about the nature of thought is inappropriate. In fact, even the
discussion of how many bits of information are processed by neurons is
untenable without knowing the code used by the neurons. If the code is
analog the number of processed bits/neuron is limited only by the noise in
the transmitter, communication line and receiver. At the other extreme, if
the code is binary then the limiting factor on the number of processed
bits/neuron is time.
Despite these limitations, it is possible to understand the function of the
brain. We already know a tremendous amount about the function of the
brain, what we do not know and may never know, is what constitutes the
abstract concept commonly refered to as thought.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Robert M. Caudle "If I had my life to
NAB, NIDR, NIH live over, I'd be a
Bldg. 49, Rm 1A-11 plumber."
9000 Rockville Pike A. Einstein
Bethesda, MD 20892
Caudle at yoda.nidr.nih.gov
or
Caudle at irp.nidr.nih.gov
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