What term describes the state of a neuron when it is not sending signals or being stimulated?

The state of a neuron when it is not sending signals or being stimulated is referred to as the resting potential. During this period, the neuron maintains a stable, negative internal charge relative to the outside environment, typically around -70 millivolts. This resting state is crucial for the neuron to be prepared for action potentials, which occur when the neuron is activated by stimuli.

Resting potential is maintained by the distribution of ions across the neuron's membrane, particularly sodium and potassium ions, with sodium channels being closed and potassium channels allowing limited permeability. This electrical gradient is fundamental for the signaling processes of neurons.

The other terms in the choices refer to different aspects of neuronal signaling. The activation potential is not a standard term; rather, action potential is used to describe the rapid rise and fall of voltage during signal transmission. The refractory period refers to the time following an action potential when a neuron is unable to fire another action potential due to ion channel dynamics. Hyperpolarization is a phase where the membrane potential becomes more negative than the resting potential, but it still occurs within the context of action potentials and is not indicative of the resting state.