Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 17: Poster II
BP 17.46: Poster
Mittwoch, 25. März 2009, 17:15–19:45, P3
Clusters of sustained activity in sparse networks - the influence of topology on networks bursts — •Olav Stetter1, Anna Levina1,2, and Theo Geisel1,2 — 1Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany — 2BCCN Göttingen, Germany
Recent studies demonstrated the dependence of the avalanche size in neuronal networks on the number and strength of its connections. In different experimental settings a similar dependence of the averaged network activity on the size of an external stimulus has been shown.
Additionally, in these experiments the temporal order of activation is shown to be non-random: There exists a topological hierarchy with a number of neurons that are more likely to take part in an early phase of synchronized network activity ("burst"). Their activity can in fact be used to predict the following network behavior.
Here we ask what characterizes these burst initiation zones. We use a simplified, analytically tractable model and concentrate on relations between the average number of neurons that take part in an avalanche (related to measurements using fluorescent dye imaging) and parameters of the network. We observe that certain classes of topological structures can enable the model network to exhibit sustained activity which then leads to an activation of large parts of the network. The likelihood of such sustained activity depends on characteristics of the network such as the number and strength of connections and the dependence of connection probability on the distance (related to the degree-degree correlation).