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A Unified Frequency Domain Model to Study the Effect of Demyelination on Axonal Conduction.

Chaubey S, Goodwin SJ - Biomed Eng Comput Biol (2016)

Bottom Line: The ability to transfer function in the frequency domain will help reduce effort and will give a much more realistic feel when compared to the classical time-based approach.Once a transfer function is identified, the conduction as a cascade of each linear time invariant system-based transfer function can be modeled.Using this approach, future studies can model the loss of myelin in various parts of nervous system.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.

ABSTRACT
Multiple sclerosis is a disease caused by demyelination of nerve fibers. In order to determine the loss of signal with the percentage of demyelination, we need to develop models that can simulate this effect. Existing time-based models does not provide a method to determine the influences of demyelination based on simulation results. Our goal is to develop a system identification approach to generate a transfer function in the frequency domain. The idea is to create a unified modeling approach for neural action potential propagation along the length of an axon containing number of Nodes of Ranvier (N). A system identification approach has been used to identify a transfer function of the classical Hodgkin-Huxley equations for membrane voltage potential. Using this approach, we model cable properties and signal propagation along the length of the axon with N node myelination. MATLAB/Simulink platform is used to analyze an N node-myelinated neuronal axon. The ability to transfer function in the frequency domain will help reduce effort and will give a much more realistic feel when compared to the classical time-based approach. Once a transfer function is identified, the conduction as a cascade of each linear time invariant system-based transfer function can be modeled. Using this approach, future studies can model the loss of myelin in various parts of nervous system.

No MeSH data available.


Related in: MedlinePlus

Architecture of the implemented model of the myelination sheath between two Nodes of Ranvier. This shows both side and cross-sectional views illustrating the parameters required for computation.
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f5-becb-7-2016-019: Architecture of the implemented model of the myelination sheath between two Nodes of Ranvier. This shows both side and cross-sectional views illustrating the parameters required for computation.

Mentions: In Equation 3, we see the overall single chamber transfer function of the neuron. The transfer function has been derived by the system identification method in MATLAB. We can see that the transfer function has an right hand plane (RHP) zero and two left hand plane (LHP) poles (dominant). This creates an approximate transfer function relating to the input injection current with the membrane potential with the appropriate phase responses for any localized region of axonal conduction. The overall neuron can be divided into three important regions: soma (the cell body), the periodic unmyelinated portions of axon, and the periodic myelinated portions of the axons. These three portions are illustrated in Figure 4. This figure shows the frequency domain circuit model for the unmyelinated section. The inputs and outputs are buffered from the external (chemical/electrical) environment using buffers, and the central response is governed by the LTI transfer function. The parameters of this transfer function depend on the radius and the length of the periodic myelinated portions. Figure 5 shows the proposed frequency domain model for the myelinated section of the axon. There is a transport delay caused by this section due to the repetition of the AP from its receiving end to its propagating end. The delay of this section depends on the radii of unmyelinated and myelinated portions and the length of the capsule as shown in the figure. The overall transfer function of the entire length will be the result of the cascade of such sections in alternate fashion (cascade of the sections of Figs. 4 and 5).


A Unified Frequency Domain Model to Study the Effect of Demyelination on Axonal Conduction.

Chaubey S, Goodwin SJ - Biomed Eng Comput Biol (2016)

Architecture of the implemented model of the myelination sheath between two Nodes of Ranvier. This shows both side and cross-sectional views illustrating the parameters required for computation.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4836623&req=5

f5-becb-7-2016-019: Architecture of the implemented model of the myelination sheath between two Nodes of Ranvier. This shows both side and cross-sectional views illustrating the parameters required for computation.
Mentions: In Equation 3, we see the overall single chamber transfer function of the neuron. The transfer function has been derived by the system identification method in MATLAB. We can see that the transfer function has an right hand plane (RHP) zero and two left hand plane (LHP) poles (dominant). This creates an approximate transfer function relating to the input injection current with the membrane potential with the appropriate phase responses for any localized region of axonal conduction. The overall neuron can be divided into three important regions: soma (the cell body), the periodic unmyelinated portions of axon, and the periodic myelinated portions of the axons. These three portions are illustrated in Figure 4. This figure shows the frequency domain circuit model for the unmyelinated section. The inputs and outputs are buffered from the external (chemical/electrical) environment using buffers, and the central response is governed by the LTI transfer function. The parameters of this transfer function depend on the radius and the length of the periodic myelinated portions. Figure 5 shows the proposed frequency domain model for the myelinated section of the axon. There is a transport delay caused by this section due to the repetition of the AP from its receiving end to its propagating end. The delay of this section depends on the radii of unmyelinated and myelinated portions and the length of the capsule as shown in the figure. The overall transfer function of the entire length will be the result of the cascade of such sections in alternate fashion (cascade of the sections of Figs. 4 and 5).

Bottom Line: The ability to transfer function in the frequency domain will help reduce effort and will give a much more realistic feel when compared to the classical time-based approach.Once a transfer function is identified, the conduction as a cascade of each linear time invariant system-based transfer function can be modeled.Using this approach, future studies can model the loss of myelin in various parts of nervous system.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.

ABSTRACT
Multiple sclerosis is a disease caused by demyelination of nerve fibers. In order to determine the loss of signal with the percentage of demyelination, we need to develop models that can simulate this effect. Existing time-based models does not provide a method to determine the influences of demyelination based on simulation results. Our goal is to develop a system identification approach to generate a transfer function in the frequency domain. The idea is to create a unified modeling approach for neural action potential propagation along the length of an axon containing number of Nodes of Ranvier (N). A system identification approach has been used to identify a transfer function of the classical Hodgkin-Huxley equations for membrane voltage potential. Using this approach, we model cable properties and signal propagation along the length of the axon with N node myelination. MATLAB/Simulink platform is used to analyze an N node-myelinated neuronal axon. The ability to transfer function in the frequency domain will help reduce effort and will give a much more realistic feel when compared to the classical time-based approach. Once a transfer function is identified, the conduction as a cascade of each linear time invariant system-based transfer function can be modeled. Using this approach, future studies can model the loss of myelin in various parts of nervous system.

No MeSH data available.


Related in: MedlinePlus