Reach a threshold of about −55 mV and a neuron fires an all-or-nothing spike: sodium floods in, then potassium floods out. Hit Stimulate and follow the voltage.
Action potential
Resting−70 mV
💡 It's all-or-none: below threshold, nothing happens; at threshold, you get the same full-size spike every time. A stronger stimulus fires them more often, not bigger.
📷 Reference image
A real labeled figure to compare with the interactive above.
The Action Potential — OpenStax, CC BY 4.0 (via Wikimedia Commons)
