Workshop CNS*2011 Stockholm (27-28, July 2011)

Reciprocal interactions of dynamical changes in network structure and function

Chair: Markus Butz and Arjen van Ooyen

Network structure determines the flow of electrical activity in every neural network and determines its functional and computational properties. Electrical activation of the neuron goes along with an intracellular increase in calcium which induces morphological alterations of the neuron on a slower time scale. Morphological changes, such as changes in dendritic spine and axonal bouton numbers as well as elongation, retraction and branching of axons and dendrites have direct impact on network connectivity (structural plasticity) even in the adult brain: As a consequence of morphological changes, synapses may break, new synapses can form and axonal branches can be re-routed. Rewired network connectivity, in turn, gives rise to an altered activity dynamic and may hold as a source for long term memory formation. Experimental data further support the notion that structural plasticity is not necessarily Hebbian-like but may serve as a neuronal mechanism to maintain electrical activity at a certain setpoint (neuronal homeostasis). Local structural changes at the single neuron compensating lasting disturbances in electrical activity may entail alterations in global network topology. Conversely, global topology can have impact on local compensation since certain network topologies may better support local structural plasticity mechanisms for maintaining neuronal homeostasis than others. These complex reciprocal interactions between structural changes and activity dynamics as well as local and global effects of structural plasticity necessitate theoretical modeling approaches to elucidate rapidly growing experimental data showing structural plasticity during memory formation and following brain lesions and degeneration. Therefore, the goal of this workshop is to bring together experimentalists and theoreticians in each session. Every session addresses one particular aspect of this topic and closes with a plenary discussion with all speakers of this session to integrate the different perspectives and approaches.