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Updated: Aug 11, 2026
10:44
Two-photon Imaging of Cellular Dynamics in the Mouse Spinal Cord
Published on: February 22, 2015
Conduction through demyelinated plaques in multiple sclerosis: computer simulations of facilitation by short
Summary
Shortening nerve fiber segments near demyelination can help electrical signals (action potentials) conduct past damaged areas. This finding may explain how some axons maintain function despite myelin loss.
Area of Science:
- Neuroscience
- Computational Biology
- Cellular Electrophysiology
Background:
- Action potential propagation along axons can be interrupted by demyelination.
- Sufficient sodium channel density in demyelinated regions is crucial for continuous conduction.
- Impedance mismatch at focal demyelination sites can cause conduction failure.
Purpose of the Study:
- To investigate conditions promoting action potential conduction into and beyond demyelinated zones.
- To examine the effect of proximal internode length reduction on conduction past demyelination.
Main Methods:
- Computer simulations were employed to model axonal conduction.
- The study focused on the impact of reducing the length of internodes adjacent to demyelinated regions.
Main Results:
- Reducing the length of the two internodes closest to the demyelinated region to approximately one-third of normal length facilitated conduction.
- Shorter internodes enabled action potentials to successfully propagate beyond the demyelinated plaque.
Conclusions:
- Reduced internode length can promote conduction past focally demyelinated zones.
- Observed histological reductions in internode length may possess functional significance for axonal conduction in demyelinated fibers.
Related Concept Videos
01:41Action Potentials
Overview
01:14Action Potential
Neurons communicate by firing action potentials—the electrochemical signal that is propagated along the axon. The signal results in the release of neurotransmitters at axon terminals, thereby transmitting information to the nervous system. An action potential is a specific "all-or-none" change in membrane potential that results in a rapid spike in voltage.
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
01:19The Role of Ion Channels in Neuronal Computation
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
01:14Action Potential
Neurons communicate by firing action potentials—the electrochemical signal that is propagated along the axon. The signal results in the release of neurotransmitters at axon terminals, thereby transmitting information to the nervous system. An action potential is a specific "all-or-none" change in membrane potential that results in a rapid spike in voltage.
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
01:23Propagation of Action Potentials
The propagation of an action potential refers to the process by which a nerve impulse, or "action potential," travels along a neuron.
Neurons (nerve cells) have a resting membrane potential, with a slightly negative charge inside compared to outside. This is maintained by ion channels, such as sodium (Na+) and potassium (K+) channels, which control the flow of ions. When a stimulus, like a touch or a signal from another neuron, triggers the neuron, sodium channels open, allowing sodium ions to...
Neurons (nerve cells) have a resting membrane potential, with a slightly negative charge inside compared to outside. This is maintained by ion channels, such as sodium (Na+) and potassium (K+) channels, which control the flow of ions. When a stimulus, like a touch or a signal from another neuron, triggers the neuron, sodium channels open, allowing sodium ions to...