Origin of the kink of somatic action potentials
© Teleńczuk et al. 2015
Published: 4 December 2015
The Hodgkin and Huxley (1952) model of action potential (AP) generation accounts for many properties of APs observed experimentally and has been successfully used in modeling neurons of different types. In this model, however, the spike onset is much shallower than in experimental recordings from the soma suggesting different activation properties of sodium channels in the real tissue. To explain the origin of the observed sharpness (kink) in the spike onset three hypotheses were proposed: 1. Cooperative hypothesis: sodium channels cooperate in the axon initial segment, which makes their collective activation curve much sharper . However, there is no experimental evidence for this hypothesis. 2. Active backpropagation hypothesis: spikes are initiated in the axon and backpropagate to the soma. The kink is caused by the sharpening of the axonal spike by active conductances during its backpropagation through the axon . 3. Compartmentalization hypothesis: the kink comes from distal initiation and the current sink caused by the difference in the size of the soma and axon .
MTT is the recipient of an École des Neurosciences de Paris (ENP) Graduate Program fellowship and the Région Ile-de-France (DIM Cerveau et Pensée). This work was also supported by Agence Nationale de la Recherche (ANR-14-CE13-0003).
- Naundorf B, Wolf F, Volgushev M: Unique features of action potential initiation in cortical neurons. Nature. 2006, 440 (7087): 1060-1063.PubMedView ArticleGoogle Scholar
- Yu Y, Shu Y, McCormick D: Cortical action potential backpropagation explains spike threshold variability and rapid-onset kinetics. J Neurosci. 2008, 28 (29): 7260-7272.PubMedPubMed CentralView ArticleGoogle Scholar
- Brette R: Sharpness of spike initiation in neurons explained by compartmentalization. PLoS Comp Biol. 2013, 9 (12): e1003338-View ArticleGoogle Scholar
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