What change in a neuron's electrical state is associated with an increased likelihood of action potentials?

The increased likelihood of action potentials in a neuron is primarily associated with depolarization. Depolarization occurs when the membrane potential of the neuron becomes less negative (or more positive) compared to its resting state. This change is typically due to the influx of sodium ions (Na+) through voltage-gated ion channels, which reduces the negative charge inside the neuron.

When depolarization reaches a certain threshold, it triggers the opening of more sodium channels, leading to a rapid spike in membrane potential that constitutes the action potential. This process is fundamental for the generation and propagation of electrical signals in the nervous system, allowing neurons to communicate effectively with each other.

While excitation often refers to the general concept of stimulating a neuron, it does not specify the electrical change as precisely as depolarization does. Hyperpolarization and inhibition, on the other hand, make the inside of the neuron more negative and therefore decrease the likelihood of firing an action potential.