What is "Mind" in Terms of Brain Function

F. Frank LeFever flefever at ix.netcom.com
Wed Dec 2 21:47:57 EST 1998



Tobi was quite brave to attempt an answer to this recurring question,
and did an excellent job rather concisely!  Deserves "reprinting"
because it was sooon lost in this newsgroup's usual flood (much of it 
nonsense).

I'll just add one or two thoughts...  At the end of Elizabeth
Warrington's talk at the NY Academy of Sciences two evenings ago (see
my post on "Knowledge Systems in the Brain" someone asked how she would
put it all together again after she had shown how "it" (call it mind,
if you will) could be taken apart; she confessed she could not, but
alluded vaguely to frontal lobe functions, which prompts me to talk
about different LEVELS of integration.  

There is, of course the very gross level of integration via (mainly)
the corpus callosum, allowing interhemispheric monitoring  (without the
cc this is very impoverished--cf. famous examples of left hemisphere
not being able to say precisely what the right hemisphere saw but
somewhat aware of the emotional valence of the stimulus).

There is also the frontal lobe monitoring and tying together various
aspects of posterior cortical representations (extensively explored by
Joaquim Fuster).

The dissociations revealed by Dr. Warrington's patients are perhaps at
a more basic level: one, for example, could not connect any aspect of
the concept of an inanimate object (e.g. a hammer) with its visual
appearance, but could do so when it was named, and had no trouble with
visual representations of animals; another could identify animals
visually but could not describe them when they were simply named--and
had no such problem with inanimate objects.

Conceivably, this is a matter of separate "memory stores" being
selectively destroyed (by stroke), rather than routes between them
being lost, but even so they imply another level of integration, a bit
above the "black" and "horizontal bar" level.  Do we invoke numerous
interconnections, or the "40Hz" connection?

(Hmmm...has anyone looked at these "40Hz" integrations after focal
lesions??)

Of course, these are not mutually exclusive.  I've heard Rodolfo Llinas
describe differences in transmission times of neurons from disparate
sources converging on a common target so that their signals arrive at
the same time...

Gee, if I'd thought of all this before, I would have invited Llinas to
Warrington's talk! (He's at NYU, only about 1.5 miles from NYAS!)

(Maybe I should be more explicit: Llinas is one of the exponents of the
synchronized activity idea Tobi discussed, and 40Hz is the noominal
value often cited in these studies)

F. Frank LeFever, Ph.D.
New York Neuropsychology Group



In <36641691.6DC5E700 at mail.rz.uni-duesseldorf.de> Tobias Kalenscher
<kalensch at mail.rz.uni-duesseldorf.de> writes: 
>
>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)
>> Rex
>
>
>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.
>Cheers,
>Tobi
>
>
>
>




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