Tell me something, I've just finished reading your reply and I would like to
know what you think of the following. If the brain processess information in
both analogue and binary forms (more in the case of the former, according to
u ;-)), then is it truly a hopeless cause to ever think that a artificial
sentient being can be created using the limited computer technology we have
access to??? I mean, a graded response must on the molecular scale be
incomprehensibly complex on each occasion that it is initiated, and thus no
correlation will be ever be found between one graded response and the
situation that it may produce (i.e. an emotion for example) - I suppose this
also depends on whether u believe that information can be processed on such
a microscopic scale.
I respect and know that the brain does indeed possess graded responses,
and as I have said, each one must on the molecular scale be unique and thus
makes understanding the phenomenon of consciousness totally beyond our
grasp. Does this make sense? How can a seemingly random event give rise to
the coherence patterns of mental activity? Is this question answerable?
T.L.S.
Richard Norman <rsnorman at mediaone.net> wrote in message
news:iEUp5.1660$_e4.240409 at typhoon.mw.mediaone.net...
> I think you are missing the importance of what we two Richards are
> saying. The fact is that there are, indeed, large numbers of neurons
> that work completely without action potentials in any form. And many
> neurons that do produce action potentials still interact with
> dendro-dendritic synapses that are completely graded. It is quite likely
> that most of the important "computations" done by the nervous system
> are in this graded format. Only when a message must be transported
> some distance is it translated into the binary form of the all-or-none
> action potential.
>> "Theophilus Samuels" <theophilus.samuels at btinternet.com> wrote in message
> news:8o91ca$6ro$1 at plutonium.btinternet.com...> > I understand what you are trying to say and I agree with you. The
original
> > thought was that the 'brain is sorta like a computer that is not based
on
> > binary' - what exactly was this fellow trying to say?
> > Sometimes, one should break down a problem into its simplest
components.
> > The neuron initiates an action potential at the axon hillock and this
> > 'event' can be manipulated by other synapses, be they inhibitory or
> > excitatory via dendrodendritic, axosomatic or even axoaxonic
interactions.
> > Here is a basic fact, only when the potential difference across the
> membrane
> > component reaches the threshold potential is an action potential
> initiated -
> > given, that graded action potentials can occur without reaching this
> > potential, but again remember, in the brain what is the use of a graded
> > potential in the realms of information processing?? Here is where I
think
> we
> > have got our wires crossed, I am referring to the way information is
> handled
> > within the brain.
> > Thus, I am referring to is the 'all or nothing' response generated by
> > neurons in the form of the overstated AP. This is what is ultimately
used
> to
> > carry information from one part of the brain to the other! For instance,
> > information coming in from the left visual field is processed by the
right
> > occipital cortex and vice versa. Thus, the only way for both occipital
> areas
> > to communicate with each other is via the corpus callosum, or more
> > specifically via AP travelling through these myelinated axons - there is
> the
> > key, ACTION POTENTIALS, or in computer terms ON events, there is no way
> that
> > graded AP can give rise to corticocortical interactions on such scales.
> > To close, what I am saying is that ultimately the first and foremost
> level
> > of processing within the brain can only be the ON or OFF AP fired at
> > DIFFERENT FREQUENCIES - there is where we shall find the greatest
> > difference, a difference that no computer engineer will probably be ever
> to
> > replicate, that of AP firing frequencies to process information.
> >
> > T.L.S.
> >
> >
> > "Richard L. Hall" <rhall at webmail.uvi.edu> wrote in message
> > news:v0422080ab5cc75761001@[146.226.154.76]...
> > >
> > > Yep...most brain cells use grade synaptic transmission driven by
> > > slight changes in potential. Even at "resting" potentials some cells
> > > release neurotransmitter. Thus, synaptic interactions merely modify
> > > a continuous process. This has the advantages of:
> > >
> > > 1. reducing the response time of the system,
> > > 2. reducing the requirements for large signal to noise resolution
> > > while increasing
> > > information content, and
> > > 3. averaging the rates of energy consumption so you do not have
> problems
> > like
> > > running out of fuel just when you need maximal computing power.
> > >
> > > The response of an on/off system driven by action potentials would be
> > > complicated by refractory periods and make it hard to summate
> > > information....timing is everything.
> > >
> > > A system that is constantly transmitting information essentially
> > > integrates signals and noise. Since noise is random, it falls out
> > > over time making it possible to detect smaller signals. As a bonus,
> > > a constantly active system can either increase or DECREASE in
> > > activity giving even more flexibility and information value.
> > >
> > > The brain has virtually no energy reserves and without this
> > > adaptation, a sudden increase in energy demand would be fatal.
> > >
> > > Nifty stuff this evolution.
> > >
> > > rlh
> > >
> > > >Surely it IS correct. Action potentials are widely misunderstood to
be
> > > >the be-all and end-all of nervous system information processing.
They
> > are,
> > > >indeed, useful and important for transmitting information over any
> > "large"
> > > >distance, that is a few millimeters or more. But at the cellular
> level,
> > a
> > > >few
> > > >millimeters is an enormous distance and graded "analog" potentials
> along
> > > >with graded (analog) transmitter release form a large portion of the
> > > >information processing in local circuits. The best example of this
is
> > > >perhaps
> > > >the vertebrate retina, where the receptor cells (rods and cones), the
> > > >horizontal
> > > >cells, and the bipolar cells all do their thing without action
> > potentials.
> > > >The
> > > >amacrine cells produce half-hearted action potential and it is only
the
> > > >retinal
> > > >ganglion cells, who must send their output a long distance down the
> optic
> > > >nerve, that produces honest-to-goodness classical action potentials.
> > > >
> > > >And in days past, there were large numbers of analog computers in use
> > > >doing all kinds of engineering computations and simulations -- adding
> and
> > > >subtracting, multiplying and dividing, even integrating and
> > differentiating
> > > >in
> > > >the solution of complex systems of differential equations without the
> > need
> > > >for a "On/Off" events. Indeed, the very term "digital computer" was
> > > >necessary
> > > >to distinguish the newcomers from the ordinary, more common analog
> > > >variety.
> > > >
> > > >
> > > >"Theophilus Samuels" <theophilus.samuels at btinternet.com> wrote in
> message
> > > >news:8o6f77$ri1$1 at plutonium.btinternet.com...> > > > > > > It sounds as though the brain is sorta like a computer that
is
> > not
> > > >based
> > > > > on
> > > > > > > binary.
> > > > > >
> > > > > > Right.
> > > > >
> > > > > Surely that is incorrect? The fundamental principle used by
> computers
> > > >relies
> > > > > on 'ON' and 'OFF' events, or in binary form, 1's and 0's. Now
> > consider the
> > > > > neurons working within the brain. Essentially, all they do is
> > initiate
> > > > > action potentials that either produce excitatory or inhibitory
> > responses -
> > > > > 1's or 0's. Thus, you can actually say that the brain does indeed
> > work on
> > > >a
> > > > > binary system IN principle. The MAIN difference between the
binary
> > system
> > > > > used within a CPU and a brain, is that neurons are capable of
> firing
> > at
> > > > > differing rates, i.e. information in the brain is FREQUENCY
coded.
> So
> > to
> > > > > reiterate, the firing of neurons does indeed use a binary
principle
> > to
> > > > > create, well...., you or I.
> > > > >
> > > > > T.L.S.
> > > > >
> > > > > <dag.stenberg at helsinki.nospam.fi> wrote in message
> > > > > news:8o55if$nvm$1 at oravannahka.helsinki.fi...> > > > > > Phoenix <phoenix42 at uswest.net> wrote:
> > > > > > > It sounds as though the brain is sorta like a computer that
is
> > not
> > > >based
> > > > > on
> > > > > > > binary.
> > > > > >
> > > > > > Right.
> > > > > >
> > > > > > > Since the computers we
> > > > > > > currently used are binary based, I wonder if we'll have to
> > develop new
> > > > > > > computers that aren't binary based ...
> > > > > >
> > > > > > Before digital computers, there were analog computers.
> > > > > >
> > > > > > Dag Stenberg
> > > > >
> > > > >
> > >
> > > Richard L. Hall, Ph.D.
> > > Comparative Animal Physiologist
> > >
> > > University of the Virgin Islands
> > > 2 John Brewers Bay
> > > St. Thomas, U.S.V.I. 00802
> > >
> > > 340-693-1386
> > > 340-693-1385 FAX
> > >
> > > rhall at uvi.edu> > >
> > > "Live life on the edge...the view is always better" rlh
> > >
> > >
> > > ---
> >
> >
>>
