Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 14: Neuronal and Sensory Systems
BP 14.5: Vortrag
Mittwoch, 25. März 2009, 15:15–15:30, HÜL 186
From Integrator to Resonator: The effect of dendrites on neuronal excitability — •Christoph Kirst1, Andreas Herz2, and Martin Stemmler2 — 1Network Dynamics Group, MPI for Dynamics and Self-Organization and BCCN Göttingen, Germany — 2LMU and BCCN München
Neurons fall into two excitability classes: Type I integrates over synaptic inputs, while type II exhibits a resonance to a particular synaptic frequency [1]. Neuronal excitability is a function not only of the underlying ion-channel kinetics but also of the neuron’s spatial structure. For example, the addition of a dendritic tree can change a neuron from a resonator into an integrator [2]. Here we show that the opposite transition can also occur: the presence of dendrites changes a saddle node on limit cycle bifurcation into a Hopf bifurcation, leading to a resonance where there was none before.
In a Morris-Lecar neuron model we show how an increase in the dendritic leak – e.g. by increasing the dendritic membrane surface – induces a change from type I to type II excitability. We analyze the underlying bifurcation structure to reveal the mechanism and the universality of such a transition. Consequences for the dynamics of networks of such neurons are discussed.
[1] G. B. Ermentrout, Neural Comput. 8, 979 (1996); Izhikevich E.M.Dynamical Systems in Neuroscience: The Geometry of Excitability and Bursting. MIT Press (2007).
[2] J. A. Goldberg, C. A. Deister and C. J. Wilson, J. Neurophysiol. 97, 208 (2007).