NEURO DISCUSSION

Dear colleagues,

Given the delay of our volunteers, perhaps we could start up the neuro
discussion rather informally. As a provocation, I suggest the consideration
of the following initial topics (below). They are taken from some classical
discussions during the 70's and 80's by Horridge, Purves, Fox, etc. The
fine tuning and "aggiornamento" by our fis neuroscientists would be very
welcome.

1. STRANGENESS OF NEURONS

Indeed a very strange type of cell: amazing form, formidable cytoskeleton,
variable "tree" of synapses, multiplicity of differentiated neuronal
subtypes, lack of dividing capacity...

Coupled to a very expensive functioning: maintenance of the membrane
electrical potential, very exaggerate patterns of gene expression,
hypertrophic signaling system activity, a very complex net of internal
transportations...

2. ORIGINS AND EVOLUTION OF NERVOUS SYSTEMS

Can we assume that the above very rare and expensive peculiarities are but
evolutionary responses to the "info processing" role that neurons started
to play for the sake of the whole multicellular organism?

Or maybe, can we think that at the very beginning of animal evolution,
neurons were in charge of something else ("trophic integration"???), and
then info functions gradually took over and finally supersed the old
function?

If so, instead of a neat info adaptation, neurons would be "barroque"
contraptions, and we could point to quite a few gross reminiscenses of the
old functions surviving eg, in the very mysterious molecular maintanance of
"memory"...

3. EMERGENCE OF ABSTRACT PATTERNS

In the combined dance of electrical discharges, neuromodulators, hormones,
growth and disappearance of synapses, cycles and rythms of activity... have
we finally found good approximations to a coherent set of abstract
operations which might grant learning, memory, and in general the
"simulating" capabilities of brains?

In what extent some of the present (artificial) neural nets may be a sound
model for biological neurons?

Do we have clear evidences about nonlinear phenomena, chaos, attractors,
etc. as regularly used as central processing tools within concrete brain
substructures? Or could they be mere epiphenomena stemming from a deeper
info processing strategy taking place?

4. BEHAVIORAL EMERGENCE

Hundreds and hundreds of maps are crammed into the brain of any
vertebrate--it is curious that, in comparison with the present glut of
neural net models, we have very few theories on info processing by means of
massive mapping (topological!) relationships...

The physical organization of vertebrate brains (the packing of their
cortical maps) shows an optimized STRUCTURE --several authors agree. Do we
have serious hints that a similar optimizing process may occur concerning
the overall FUNCTION?

In other words, do "variational principles" exist in order to orient the
combined info processing of the whole substructures of the vertebrate brain
granting the emergence of complex adaptive behavior? Or conversely, given
the present evidence on brain functioning, is the search for such an
overall "variational principle" underlying behavior a mere science-fiction
possibility?

5. THE BRAIN VERSUS THE MIND: THE PHENOMENON OF CONSCIOUSNESS

In what extent could consciousness be amenable to brain sci. analysis
(evolutionary plus neuroscientific)? Do we forcefully need to invoque
quantum phenomena--and even New Physics-- in order to scientifically talk
about mind and consciousness?

Is it plausible that in the course of their bizarre evolutionary
trajectory, did nervous systems of mammals (primates) stumble upon New
Physics themes--and discovered "consciousness" as a quantum subatomic
epiphenomenon emerging from special protein-components of their
cytoskeletons? Perhaps even including, and integrating, the dynamics of
intracellular second messengers (as expostulated by Liberman)... and
crossing sort of a complexity threshold.

If so, could such consciousness phenomena ever emerge from logically
"shallow" non-protein components (eg, Silicon components)? Is, then, the
fancy quest for Artificial Intelligence necessarily doomed, unless
reoriented towards the Biological processing?

best greetings

Pedro

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Pedro C. Marijuan. FAX 34 976 761861 and / 762111. TEL / 761927
Dept. Ingenieria Electronica y Comunicaciones
CPS, Universidad de Zaragoza, Zaragoza 50015, SPAIN
email: marijuan@posta.unizar.es
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Received on Tue Apr 21 14:27:18 1998