What principle describes a neuron's reaction of either firing completely or not firing at all?

The concept that describes a neuron's reaction of either firing completely or not firing at all is known as the all-or-none principle. This principle states that once a neuron reaches a certain threshold of stimulation, it will fire an action potential with a consistent strength and duration, leading to the release of neurotransmitters. If the stimulation does not reach the threshold, the neuron will remain at its resting state and will not fire.

This principle ensures that neural communication is reliable and consistent, as the strength of the signal does not vary with the intensity of stimulation, but rather, it is an all-or-nothing response. The action potential itself is a result of this principle, but it does not specify the nature of the firing's completeness or its binary aspect. The resting potential refers to the stable, negative charge of the neuron when it is not firing, and while the threshold principle relates to the level of stimulation required to trigger an action potential, it does not encapsulate the binary firing nature as clearly as the all-or-none principle does.