6.021/Notes/2006-11-03
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Hodgkin-Huxley
- Each factor can also be written as rates [math]\displaystyle{ \alpha,\beta }[/math]
- [math]\displaystyle{ x_\infty=\frac{\alpha_x}{\alpha_x+\beta_x}, \tau_x=\frac{1}{\alpha_x+\beta_x} }[/math]
- The effect of temperature is to multiple rates by [math]\displaystyle{ K_T = 3^{T_c-6.3} }[/math]
- An increase in temperature decreases all 3 time constants but has no effect on the final values.
- At high temperature, no action potential is seen
- There's another time constant due to capacitance in membrance
- Changes in conductances have time delay before membrane potential changes
- [math]\displaystyle{ \tau_M }[/math] (membrane "RC" time constant) is about 1-2 ms.
- [math]\displaystyle{ \tau_m \approx 1-2 ms, \tau_n \approx 3-4 ms, \tau_h \approx 3-4 ms }[/math]
- increase in temperature causes the [math]\displaystyle{ G_K }[/math] wave to catch up with the [math]\displaystyle{ G_{Na} }[/math] wave
- As increase temperature, both approach [math]\displaystyle{ \tau_M }[/math]. If waves go at same speed, cannot have action potential.
