[Comp-neuro] Re: Attractors, variability and noise

Leslie Smith l.s.smith at cs.stir.ac.uk
Fri Aug 15 15:00:59 CEST 2008

Andrew Coward wrote:

> ...
> Understanding the brain will require an analogous hierarchy of
> descriptions. In other words, we have to find good approximations at
> several intermediate levels that can be mapped both into psychology
> and into more detailed neuron type models. One attempt at such a
> multilevel theory is [Coward 2005]. The danger of massive neuron
> modelling efforts is that we can create a system which may have
> properties similar to brains but do not help with genuine
> intellectual understanding.

Engineers build complex system using hierarchical design: without  
this makes them much easier to design and debug and extend etc. But
biological systems are not designed as such: as such they don't need to
work within hierarchies. Entities within biological systems can interact
across levels. And they do: even simple GA based experiments like Adrian
Thompson's FPGA's took advantage of unexpected interactions on an FPGA,
and (for example) animal brains often use neuromodulators whose release
affects a volume of the brain. Clearly, crossing levels is dangerous
(which is why engineers avoid it) but it can result in highly efficient
"clever" solutions (which is why evolution can utilise them).

A multi-level theory may help us to take an engineer's view of neural
systems, but the view that it results in is likely to be incomplete.


Professor Leslie S. Smith,
Head, Dept of Computing Science and Mathematics,
University of Stirling,
Stirling FK9 4LA, Scotland
l.s.smith at cs.stir.ac.uk
Tel (44) 1786 467435 Fax (44) 1786 464551
www http://www.cs.stir.ac.uk/~lss/

Academic Excellence at the Heart of Scotland.
The University of Stirling is a charity registered in Scotland, 
 number SC 011159.

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