Neuron workbench

The Hodgkin–Huxley model of the squid giant axon, solved live. Three conductances, four state variables, six rate constants, exactly as published in 1952. Move a slider and the model is re-solved — nothing here is a recording.

10.0 µA/cm²

Below rheobase the cell charges and stops. Above it, it fires repetitively.

6.3 °C

Gating is chemistry: Q10 of 3. Warming narrows the spike. Above about 25 °C this model stops firing altogether — a real result, and why squid are not warm-blooded.

Spikes

3

Rate

75Hz

Peak

40.3mV

Half-width

1.36ms

Membrane potential

-90-2050restE(Na)E(K)060 msmV

Gating variables

00.51060 msopen
  • m — Na activation
  • h — Na inactivation
  • n — K activation

m rises first and fastest — that is the spike. h falls behind it and shuts sodium off, which is the refractory period. n rises last and repolarises.

Ionic currents

-9000900060 msµA/cm²

Outward-positive, the electrophysiological convention. Sodium goes NEGATIVE as the spike rises — ions moving inward. Peak conductances this sweep: 32.7 and 12.7 mS/cm².