Each level shows a target recording. Tune the density of each ion channel until your cell produces the same action potential.
Slide to change how many channels of each type the membrane carries.
| Feature | You | Target |
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Ion flow at its true rate, slowed down. Each dot stands for a fixed number of ions, so the dots that cross add up to the real number of ions moved (|I| ÷ ze). The pore opens with the channel's open probability (Po).
Under each voltage-gated channel: its steady-state activation curve (solid), with the fraction of channels open running from closed on the left to open on the right and membrane potential on the shared vertical axis. The dashed curve is inactivation, from inactivated (left) to available (right). The red line is the membrane potential; it crosses each curve at that channel's own point, and the dashed horizontal line marks its activation threshold (the shaded zone above it is where the channel opens). Ring: where the gate is heading; marker: where it is. Buckets below show the concentration of each ion inside the cell, under the channels that carry it: the dashed line is the starting level, and one action potential moves so few ions that the thin tube beside each bucket magnifies the change (tube ×N).
Each plot shows how a channel's gates respond to voltage, with V on the horizontal axis and the fraction of gates open (solid line, activation) or still available (dashed line, inactivation) on the vertical axis. The triangle (▲) marks the half-activation voltage, the diamond (◆) the half-inactivation voltage; each fills in once V has passed it, and the shaded region is above the activation threshold. The vertical line is the membrane potential now. The ring is where the gates are heading at this voltage; the filled marker is where they actually are. The accent-coloured gap between them is the delay, and the faint trail shows the path so far. Below each plot, the time constant τ (log scale) shows how slowly the gates follow at every voltage: a gap closes fast where τ is small and slowly where it is large.
Drag on the voltage or concentration plots, or the time slider, to scrub. Keys: ← → step (Shift ×10) · , . previous/next event · Space play/pause · Home/End.