clean up hodgkin-huxley

1 files changed, 27 insertions, 19 deletions

diff --git a/examples/hodgkin_huxley/model.modelica b/examples/hodgkin_huxley/model.modelica
index 782cb20..7e44547 100644
--- a/examples/hodgkin_huxley/model.modelica
+++ b/examples/hodgkin_huxley/model.modelica
@@ -1,24 +1,32 @@
 model HodgkinHuxley
-    "Predator-Prey Model"
-    parameter Real G_Na =120        "conductance";
-    parameter Real G_K  =36         "conductance";
-    parameter Real G_lk =0.3        "conductance";
-    parameter Real C    =1.0        "membrane capacitance";
+    "Model of action potential in squid neurons (1952)"
+    parameter Real C_m  =1.0        "membrane capacitance";
+    parameter Real g_Na =120        "conductance";
+    parameter Real g_K  =36         "conductance";
+    parameter Real g_L  =0.3        "conductance";
     parameter Real V_Na =115        "potential";
     parameter Real V_K  =-12        "potential";
-    parameter Real V_lk =-49.387    "leakage";
-    Real n;
-    Real alpha_n;
-    Real beta_n;
-    Real m;
-    Real alpha_m;
-    Real beta_m;
-    Real h;
-    Real alpha_h;
-    Real beta_h;
+    parameter Real V_lk =-49.387    "leak reveral potential";
+    parameter Real E_Na =-190       "equilibrium potential";
+    parameter Real E_K  =-63        "equilibrium potential";
+    parameter Real E_lk =-85.613    "equilibrium potential";
+    parameter Real n    =0.31768    "dimensionless; 0 to 1";
+    parameter Real m    =0.05293    "dimensionless; 0 to 1";
+    parameter Real h    =0.59612    "dimensionless; 0 to 1";
+    Real V_m                        "membrane voltage potential";
+    Real I              =1.0        "membrane current";
+    Real alpha_n, alpha_m, alpha_h  "rate constants";
+    Real beta_n, beta_m, beta_h     "rate constants";
 equation
-    C * der(V_m) = - G_Na * (Vm - E_Na) - G_K * (V_m - E_K) - G_lk * (V_m - V_lk);
-    der(n) = - (alpha_n + beta_n) * n + alpha_n;
-    der(m) = - (alpha_m + beta_m) * m + alpha_m;
-    der(h) = - (alpha_h + beta_h) * h + alpha_h;
+    C_m * der(V_m) = I - g_Na * m^3 * h * (V_m - E_Na) - g_K * n^4 * (V_m - E_K) - G_lk * (V_m - E_lk);
+    der(n) = alpha_n - n * (alpha_n + beta_n);
+    der(m) = alpha_m - m * (alpha_m + beta_m);
+    der(h) = alpha_h - h * (alpha_h + beta_h);
+
+    alpha_n = 0.01 * (V_m + 10) / (e^((V_m + 10)/10) - 1);
+    alpha_m = 0.1 * (V_m + 25) / (e^((V_m + 25)/10) - 1);
+    alpha_h = 0.07 * e^(V_m / 20);
+    beta_n = 0.125 * e^(V_m / 80);
+    beta_m = 4*e^(V_m/18);
+    beta_h = 1 / (e^((V_m + 30)/10) + 1);
 end HodgkinHuxley;