"Spike initiation determines how the combined inputs to a neuron are converted to an output. Since the pioneering work of Hodgkin and Huxley, it is known that spikes are generated by the opening of sodium channels with depolarization. According to this standard theory, these channels should open gradually when the membrane potential increases, but spikes measured at the soma appear to suddenly rise from rest. This apparent contradiction has triggered a controversy about the origin of spike “sharpness.” This study shows with biophysical modelling that if sodium channels are placed in the axon rather than in the soma, they open all at once when the somatic membrane potential exceeds a critical value. This work explains the sharpness of spike initiation and provides another demonstration that morphology plays a critical role in neural function."
Model Type: Neuron or other electrically excitable cell; Axon
Currents: I Sodium
Model Concept(s): Dendritic Action Potentials; Action Potentials; Action Potential Initiation; Axonal Action Potentials; Simplified Models
Simulation Environment: Brian 2 (web link to model)
Implementer(s): Brette R
References:
Brette R. (2013). Sharpness of spike initiation in neurons explained by compartmentalization. PLoS computational biology. 9 [PubMed]