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Updated: Oct 24, 2025
11:46
Axon Stretch Growth: The Mechanotransduction of Neuronal Growth
Published on: August 10, 2011
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Neural excitability increases with axonal resistance between soma and axon initial segment
Aurélie Fékété1, Norbert Ankri1, Romain Brette2
1UMR 1072, INSERM, Unité de Neurobiologie des canaux Ioniques et de la Synapse, Aix-Marseille Université, 13015 Marseille, France.
Summary
The axon initial segment
Area of Science:
- Neuroscience
- Computational Neuroscience
- Cellular Neuroscience
Background:
- The position of the axon initial segment (AIS) is crucial for neuronal excitability.
- Previous studies show conflicting results regarding AIS position and excitability.
- Theoretical models suggest increased axial resistance (Ra) may enhance excitability.
Purpose of the Study:
- To investigate the impact of axial resistance (Ra) at the axon hillock on the voltage threshold (Vth) of action potentials.
- To reconcile conflicting experimental and theoretical findings on AIS position and neuronal excitability.
Main Methods:
- Mechanical manipulation of the axon to alter axial resistance (Ra).
- Ionic substitution to modify internal ion mobility and axial resistance (Ra).
- Hodgkin-Huxley compartmental modeling to simulate changes in Vth.
Main Results:
- Increasing axial resistance (Ra) by pinching the axon lowered Vth by ~6 mV.
- Decreasing axial resistance (Ra) by increasing ion mobility elevated Vth.
- Model simulations accurately reproduced experimentally observed Ra-dependent changes in Vth.
Conclusions:
- Neuronal excitability in L5 pyramidal neurons increases with axial resistance (Ra).
- A distal shift in AIS position, which increases Ra, enhances neuronal excitability.
- These findings challenge previous assumptions and provide a new perspective on AIS function.
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