What is an action potential?

An action potential is fundamentally defined as a rapid change in electrical charge that occurs across the membrane of a nerve cell, or neuron, when it becomes activated. This event is critical for the conduction of electrical signals along the neuron and ultimately allows for communication between neurons and other cells.

When a neuron is stimulated, ion channels in its membrane open, leading to an influx of sodium ions. This causes depolarization, where the inside of the neuron briefly becomes more positively charged compared to the outside. This change in electrical charge propagates along the neuron, creating a wave of depolarization that travels down the length of the axon.

This is a pivotal process in the nervous system, enabling the transmission of information rapidly between different parts of the body. The action potential resets after reaching its peak, returning to its resting state through the repolarization process, ensuring that the neuron can fire again.

The other options, while related to neuronal function, do not accurately capture the definition of action potential. For instance, the process that deactivates neuron signals involves mechanisms like neurotransmitter uptake or receptor desensitization, which occurs after signal transmission rather than during the action potential itself. Likewise, neurotransmitter release is a separate process that follows an action potential