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Modeling extracellular space electrodiffusion during Leão's spreading depression.
A C G Almeida1, H Z Texeira, M A Duarte
1Federal University of Sao Joao del-Rei, Laboratory of Experimental and Computational Neuroscience, Pr. Dom Helvecio 74, Fabricas, Sao Joao del-Rei Minas Gerais 36301-160, Brazil. acga@usfj.edu.br
IEEE Transactions on Bio-Medical Engineering
|March 6, 2004
Summary
This study mathematically models the extracellular electric field in spreading depression (SD). The model explains the negative potential shift during SD, suggesting it originates from an electric field within the extracellular space.
Area of Science:
- Computational neuroscience
- Biophysics
- Mathematical biology
Background:
- Spreading depression (SD) is a wave of neural hypoexcitability.
- The origin of the extracellular electric field driving the DC potential shift in SD remains debated.
- Existing models often simplify the electrochemical processes involved.
Purpose of the Study:
- To present a mathematical derivation of the extracellular electric field within a computational model of spreading depression.
- To investigate the role of electrochemical ionic variations in the extracellular space (ECS) on the electric field generation.
- To refine computational models of SD by incorporating detailed ionic dynamics.
Main Methods:
- Developed a computational model based on Tuckwell and Miura's SD model.
- Employed electrodiffusion equations to simulate the movement of Na+, K+, Cl-, and Ca2+ ions.
- Coupled ionic movement with the electric field within the ECS.
- Calculated ionic variations electrochemically.
Main Results:
- The model successfully calculated the impact of ECS ionic changes on the electric field.
- Simulations reproduced key experimental features of spreading depression in retinal and hippocampal tissues.
- Demonstrated the ability to model the dynamic interplay between ion concentrations and electric fields.
Conclusions:
- The extracellular negative field-potential shift during SD is likely generated by an electric field within the ECS.
- A Goldman-Hodgkin-Katz type equation acting within the ECS can explain the observed potential shifts.
- This model provides a more electrochemically detailed approach to understanding SD mechanisms.