Action Potential initiation and backpropagation in Neocortical L5 Pyramidal Neuron (Hu et al. 2009)


"...Previous computational studies have yielded conflicting conclusions about the role of Na+ channel density and biophysical properties in action potential initiation as a result of inconsistent estimates of channel density. Our modeling studies integrated the immunostaining and electrophysiological results and showed that the lowest threshold for action potential initiation at the distal AIS was largely determined by the density of low-threshold Nav1.6 channels ... Distinct from the function of Nav1.6 channel, the Nav1.2 channel may control action potential backpropagation because of its high density at the proximal AIS and high threshold. ... In conclusion, distal AIS accumulation of Nav1.6 channels determines the low threshold for action potential initiation; whereas proximal AIS accumulation of Nav1.2 channels sets the threshold for the generation of somatodendritic potentials and ensures action potential backpropagation to the soma and dendrites. Thus, Nav1.6 and Nav1.2 channels serve distinct functions in action potential initiation and backpropagation."

Model Type: Neuron or other electrically excitable cell; Axon; Channel/Receptor

Cell Type(s): Neocortex U1 L2/6 pyramidal intratelencephalic GLU cell; Neocortex U1 L5B pyramidal pyramidal tract GLU cell

Currents: I K; I M; I K,Ca; I Sodium; I Calcium

Genes: Nav1.2 SCN2A; Nav1.6 SCN8A

Model Concept(s): Action Potential Initiation; Ion Channel Kinetics; Axonal Action Potentials

Simulation Environment: NEURON

Implementer(s): Hu, Wenqin [huwenqin at ion.ac.cn]; Hou, Han [hh at ion.ac.cn]

References:

Hu W, Tian C, Li T, Yang M, Hou H, Shu Y. (2009). Distinct contributions of Na(v)1.6 and Na(v)1.2 in action potential initiation and backpropagation. Nat Neurosci 12 [PubMed]