The Fitzhugh-Nagumo Model (A model for neural excitation) |
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The Fitzhugh-Nagumo modelThe Fitzhugh-Nagumo model is a model for the excitable dynamics of neural systems. The original, non-spatial version of the model describes a system that, when it is taken away from equilibrium for a sufficient extent by an external stimulus, initially runs away from this equilibrium to follow a extensive route to finally return to the equilibrium. When set in a 1D spatial setting, it predicts travelling wave dynamics that can explain the transmittance of a signal over a neuron. When set in a 2D spatial setting, it can predict a wide array of spatial patterns and dynamics, which can be explored in the model above. |
The model consists of the following partial differential equations ∂u / ∂t = u - u3 - v + ∇2u ∂v / ∂t = ϵ(u - a1v - ao) + δ∇2v Here, u is the membrane potential, and v is a recovery variable. ϵ (Epsilon), a0 and a1 are interaction constant, δ stands for the ration between the diffusivity of v to u, and ∇2 is the laplacian operator in two spatial dimensions. We adopted the version of the spatial Fitzhugh-Nagumo model that is described in “The Nonlinear Physics of Ecosystems” by Ehud Meron (2015). |