What the Neocortex Does

Sergio Navega snavega at attglobal.net
Sat Aug 12 07:24:16 EST 2000


Ray Scanlon wrote in message <39904caf.0 at ns2.wsg.net>...
>
>Gary Forbis wrote:
>>
>> I fully agree with this... (where "the brain" is read "the system of
>neurons.")
>
>Of course. One is forced to use a little shorthand to get over the ground.
>Do we speak of brains, nuclei, neurons, molecules, atoms, sub-atomic
>particles, quarks? For us, I think that the neuron is the object of choice.
>For "amygdala", read "the neurons that comprise the amygdala".
>


"For us", you mean the average neuroscientist concerned with processes
occurring at the neural level. These are only a small part of the
scientists investigating brains.

This would be slightly different for neuroscientists with concerns
at the molecular level, which will tend to see not only "neurons", but
synaptic clefts, neurotransmitter vesicles and the like. This is
one level below the "neural level".

Take computational neuroscientists, and you'll see that they are
concerned not exactly with neurons, but mainly with electrical properties
of dendrites and axons. One sect of computational neuroscientists will
develop models not of a single neuron or a dendrite, but of a group of
neurons, which enter in dynamic and chaotic synchronous oscillations.
This line of investigation (which is one level UP of the realm of
"barely neurons") is of fundamental importance to solve the
"information coding" conundrum.

Cognitive neuroscientists go even one level higher, trying to
accompany the spread of activations through the cortex when someone
sees, for example, an inverted face. From their analysis, a dynamic
picture appears, revealing notions and concepts that one can't
infer from the basic properties of a single neuron. One day we
will eventually have all these explanation levels joined one to
another. But in order to get at that, we have to deal with them
individually, because that's what we can do now (we have a limited
brain to tacle a so complex problem all at once).

You cannot say that the level of neural investigation is the
only one to be considered "scientific". Science is about the
creation of models with predictive and explanatory power. One
can't rule out cognitive scientists, if what they do can be
experimentally assessed.

Regards,
Sergio Navega.









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