hh model using forward euler in matlab

main.m
% Constants
Cm = 1; % Membrane capacitance
gNa = 120; % Sodium conductance
ENa = 115; % Sodium equilibrium potential
gK = 36; % Potassium conductance
EK = -12; % Potassium equilibrium potential
gL = 0.3; % Leak conductance
EL = 10.6; % Leak equilibrium potential
dt = 0.01; % Time step size
t_max = 50; % Maximum simulation time

% Initial values
V = 0; % Membrane voltage
m = 0; % Sodium activation variable
h = 0; % Sodium inactivation variable
n = 0; % Potassium activation variable

% Arrays to store values
V_array = zeros(1, t_max/dt);
m_array = zeros(1, t_max/dt);
h_array = zeros(1, t_max/dt);
n_array = zeros(1, t_max/dt);

% Simulation loop
for i = 1:(t_max/dt)
    % Calculate membrane currents
    INa = gNa * m^3 * h * (V - ENa);
    IK = gK * n^4 * (V - EK);
    IL = gL * (V - EL);
    
    % Update gating variables using HH model equations
    alpha_m = (0.1 * (V + 40)) / (1 - exp(-(V + 40)/10));
    beta_m = 4 * exp(-(V + 65)/18);
    alpha_h = 0.07 * exp(-(V + 65)/20);
    beta_h = 1 / (1 + exp(-(V + 35)/10));
    alpha_n = (0.01 * (V + 55)) / (1 - exp(-(V + 55)/10));
    beta_n = 0.125 * exp(-(V + 65)/80);
    
    m = m + dt * ((alpha_m * (1 - m)) - (beta_m * m));
    h = h + dt * ((alpha_h * (1 - h)) - (beta_h * h));
    n = n + dt * ((alpha_n * (1 - n)) - (beta_n * n));
    
    % Update membrane voltage using forward Euler method
    dv = (1 / Cm) * (-(INa + IK + IL));
    V = V + dt * dv;
    
    % Store values in arrays
    V_array(i) = V;
    m_array(i) = m;
    h_array(i) = h;
    n_array(i) = n;
end

% Plot the membrane voltage
time = 0:dt:t_max-dt;
plot(time, V_array);
xlabel('Time (ms)');
ylabel('Membrane Voltage (mV)');
title('Hodgkin-Huxley Model using Forward Euler');
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