Interactive Model
FitzHugh-Nagumo
Dynamics
A minimalist representation of neuronal excitability. The model simplifies the Hodgkin-Huxley equations into a 2D phase portrait, illustrating the mechanics of action potentials.
$$\frac{dV}{dt} = V - \frac{V^3}{3} - w + I_{\text{ext}}$$
$$\frac{dw}{dt} = \varepsilon(V + a - bw)$$
Biological Presets
System Parameters
Stimulus
I_ext
0.00
Timescale
ε
0.08
Threshold Shift
a
0.70
Feedback
b
0.80
Stability Analysis
Equilibrium (V*, w*)
(-1.199, -0.624)
Trace (T) / Det (D)
-0.503 /
0.115
State
Stable Spiral
Phase Portrait
V-nullcline
w-nullcline
Click and drag inside to perturb the system
Temporal Evolution
V:
-1.19
w:
-0.62