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BP: Fachverband Biologische Physik

BP 12: Neuroscience

BP 12.1: Invited Talk

Tuesday, March 27, 2007, 10:30–11:00, H44

The first micro seconds in the life of a nerve impulse — •Fred Wolf — MPI for Dynamics and Self-Organization, 37073 Goettingen, Germany

The first micro seconds in the life of a nerve impulse

Neurons process and encode information by generating sequences of action potentials(APs). In the living brain, neurons operate under an intense synaptic bombardment causing strong and seemingly random fluctuations of their membrane potentials. Recent theoretical studies have revealed that under such conditions apparently minor modifications of the initiation dynamics of APs can dramatically change the nature of AP encoding (1-4). These studies have triggered a re-evaluation of the dynamics of AP generation in real nerve cells (3-5). Intriguingly, these studies indicate that (i) the actual dynamics of neuronal APs qualitatively deviates from the predictions of the canonical and widely accepted physiological model of AP generation, the Hodgkin and Huxley model, and that (ii) the AP dynamics appears to be optimized for the processing of fast varying signals (3,4). Here, I will discuss theoretical analyses of neuronal encoding, biophysical models, and in vitro experiments supporting the hypothesis that a direct cooperativity between sodium channel molecules within the neuronal membrane forms the origin of this unanticipated phenomenon.

(1) Fourcaud-Trocme et al. J.N. 23:11628 (2003) (2) Naundorf, Geisel, Wolf J.C.N. 18:297 (2005) (3) Naundorf, Wolf, Volgushev Nature 440:1060 (2006) (4) Naundorf, Wolf, Volgushev Nature, 445:E2 (2007) (5) MacCormick, Shu, Yu Nature 445:E1 (2007)