An action potential is a rapid, all-or-nothing electrical signal that travels along the plasma membrane of a neuron. It is the fundamental means by which neurons communicate with each other. Action potentials are generated by the opening and closing of ion channels in the neuron's membrane, which allows ions to flow into and out of the neuron. This change in the electrical potential across the membrane causes the action potential to propagate down the neuron's axon.

Action potentials are essential for a variety of neural functions, including transmitting information between neurons, controlling muscle contractions, and regulating glandular secretions.