What does the term 'resting potential' refer to in neurons?

The term 'resting potential' refers to the state of a neuron when it is not actively sending an electrical signal. Specifically, it describes the electrical charge difference across the neuron's membrane during this inactive state. This difference in charge is primarily maintained by the distribution of ions, particularly sodium and potassium, with the inside of the neuron being more negatively charged relative to the outside. This resting potential is crucial for the generation of action potentials, as it sets the stage for neurons to respond to stimuli and transmit signals when necessary.

In contrast, the other options describe different aspects of neuronal activity. The first choice relates to the active state of a neuron when it is firing, which is not representative of resting potential. The third option discusses the refractory period, where a neuron is briefly unable to transmit signals after firing, and the fourth pertains to the recovery phase of an action potential, which is also distinct from the resting state. Thus, the correct understanding of resting potential is fundamental to grasping how neurons operate at both rest and during activity.