Potassium activation closing rate

Read the equation

The exponential β_n decreases as voltage rises and multiplies n in the gate’s closing term. At a fixed voltage, α_n and β_n together yield equilibrium n=α_n/(α_n+β_n) and relaxation time 1/(α_n+β_n). The expression is one component of the coupled membrane model.

Terms & definitions

How it works

Read the definition from its right-hand expression to the quantity on the left. Its surrounding source records the intended input, state, or parameter context. Where the source leaves an operation unspecified, this page preserves that gap.

Assumptions & limits

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Original context

    // α_n(V) = 0.01(V+55)/(1-exp(-(V+55)/10))
    float alpha_n(float V_) const {
        float x = V_ + 55.0f;
        if (std::abs(x) < 1e-6f) return 0.1f;
        return 0.01f * x / (1.0f - std::exp(-x / 10.0f));
    }

    // β_n(V) = 0.125*exp(-(V+65)/80)
    float beta_n(float V_) const {
        return 0.125f * std::exp(-(V_ + 65.0f) / 80.0f);
    }

    // Ionic currents
    float I_Na() const { return g_Na * m*m*m * h * (V - E_Na); }
    float I_K() const { return g_K * n*n*n*n * (V - E_K); }
    float I_L() const { return g_L * (V - E_L); }

    // Time step using Euler method

β_n(V) = 0.125*exp(-(V+65)/80)

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