What is "Mind" in Terms of Brain Function
kalensch at mail.rz.uni-duesseldorf.de
Tue Dec 1 11:17:21 EST 1998
Rex Bennett schrieb:
> Someone out there may be able to answer this for me.
> I understand, in general terms, how the brain functions. (As a layman.)
> I know that the brain is electro-chemical in function and that the
> firing of the synapses (millions of them) create the metafunction we
> tend to call "mind." This places the functions squarely in the world of
> matter/energy. However, of this metafunction we call "mind," how
> does it come to be? What is its structure? Is the mind made up of
> "brain waves?" Is it made from specific firing sequences? Is it a
> form of electron plasma?
> I know these questions may sound silly to some out there, but I
> would be appreciative if some knowledgeable soul could tell me
> the (matter/energy) physical nature of "mind" as opposed to
> the brain that creates it.
> Thanks in advance, (rbennet2 at tampabay.rr.com)
One of the many aspects of mind is an 'inner-eye function', or the ability
to represent internal states on a meta-level. This comprises not only
representations of sensory and motor functions, respectively the outcome of
their processes, but also a value assigning system. Conscious brains are
capable of optimizing their future acts in terms of flexibility and
adaptability by a monitoring mechanism additional to its signal-analysis
mechanisms. This is a second order process that monitors and analyses the
processes of the first order systems (like primary sensory signal-analysis
etc.), represents them on a meta level, compares their presumed performance
with incoming signals and computes optimized future acts. It is like a
represenation of a representation. If we can understand how neuronal
representations work in general, we can speculate how meta-representations
and therefore awareness might work under the assumption that the underlying
neuronal mechanisms are similar.
In the visual cortex, we find feature-specific neurons that show a maximum
response to a specific stimulus, like for instance a particularly shaped
optical stimulus. An object that we look at consists of a huge variety of
these features, therefore a neuronal representation of such an object might
be a coincident activity of the respective neurons. However, these cells are
often distributed over wide cortical areas and are sometimes quite distant
from each other. Hence, an important question in neuroscience today is how
these cells are recognized as representing the same object. One explanation
is that the identifying code is a synchronised oscillation-activity of these
feature-specific cells, thus the coding works on a temporal basis: Active
cells that relate to the same complex stimulus fire in a synchronized
manner. Or the other way around: If different neurons fire synchronously,
they represent parts of the same sensory stimulus. If for example a neuron
encoding the colour black and a neuron encoding a horizontal bar fire
synchronously, the subject is looking at a black bar. If we generalize this
idea to meta-representations, we might say that consciousness seems to be
related to the appropriate temporal coding, i.e. second-order
representations are nothing else but synchronous activity in the brain.
Of course, this idea has its disadvantages as well, but to answer your
question more detailed or more critically would take too long, I therefore
suggest you'll have a look at the following publication.
I am referring to an interesting and comprehensive article by Wolf Singer:
Singer, W. (1997), Consciousness and the structure of neuronal
representations, in: The Conscious Brain (1997), New York
I hope this helped you a bit.
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