Equivalent Circuit of an Axon Membrane

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Equivalent Circuit of an Axon Membrane
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Measured voltage
Input Signal
Feedback Amplifier current proportional to
difference (E-input)
Measured Current
Hodgkin Huxleys voltage clamp of the squid
giant axon
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early inward Na
late outward K
Hodgkin Huxleys voltage clamp of the squid
giant axon Current response to
hyper-polarization and de-polarization
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late outward K
early Na
Hodgkin Huxleys voltage clamp of the squid
giant axon Current response to
hyper-polarization and de-polarization
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Hodgkin Huxley separation of Na and K currents
by variation of bath Na concentration
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Separation of Na and K Current-Voltage curves
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Rapid changes in gNa
Slow changes in gK
Separation of Na and K Ionic conductance changes
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Na and K conductance at various voltage clamp
steps
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Channel openings and closings during Action
Potential
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Example of time course of changes in n n4 gK
and m, h m3h gNa
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Voltage dependence of Hodgkin-Huxley model
parameters