UNIVERSITY OF HERTFORDSHIRE
           COMPUTER SCIENCE RESEARCH COLLOQUIUM

                          presents

         "Evolutionary Selection of Neural Network
                  Structure and Function"

                     Prof. Larry Yaeger
                 (Indiana University, USA)

                5 October 2011 (Wednesday)
                       Room C152

                 Hatfield, College Lane Campus
                         1-2 pm

                 Everyone is Welcome to Attend

                 Refreshments will be available

Abstract:

I will examine the relationship between evolved neural network structure
and function, applying graph theoretical tools to the analysis of
the topology of evolved artificial neural networks and information
theoretical tools to their dynamical neural complexity. Results suggest
a synergistic convergence between network structures emerging due
to physical constraints, such as wiring length and brain volume, and
optimal network topologies evolved purely for function in the absence of
physical constraints. Increases in clustering coefficient are observed
in concert with decreases in path length, together producing a driven
evolutionary bias towards small-world networks relative to comparable
networks drawn from a passive null model. These small-world biases
are exhibited during the same period that evolution actively selects
for increasing neural complexity, and during which the model's agents
are behaviorally adapting to their environment, thus strengthening the
association between small-world network structures and complex neural
dynamics. I will also introduce a new measure of path length in graphs,
"normalized path length", that is better behaved than existing metrics
for networks comprised of disjoint subgraphs and disconnected nodes,
a novel method of quantifying the degree of evolutionary selection for
small world networks, "small-world bias", and an open source suite of
graph theoretical tools, a C++ version of Sporns, Kötter, and Rubinov's
MATLAB "Brain Connectivity Toolbox", "bct-cpp".

Work funded by the (US) National Academies and Keck Futures Initiative,
and performed in collaboration with Olaf Sporns, Steven Williams, Xin
Shuai, and Sean Dougherty.


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Speaker's Website : http://www.soic.indiana.edu/people/profiles/yaeger-larry.shtml


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Hertfordshire Computer Science Research Colloquium
http://homepages.stca.herts.ac.uk/~nehaniv/colloq