What is an action potential?

An action potential is defined as a brief electrical charge that travels down an axon. This process is fundamental to the way neurons communicate with each other. When a neuron is stimulated past a certain threshold, it becomes depolarized, which means that the inside of the neuron becomes more positively charged relative to the outside. This change in electrical charge travels rapidly along the axon, allowing the neuron to transmit information quickly and efficiently to other neurons or to muscles and glands.

The propagation of the action potential is facilitated by the opening and closing of voltage-gated ion channels along the axon's membrane, leading to a wave of depolarization that moves along the axon. This is crucial for neuronal signaling—without action potentials, the nervous system would not be able to send signals effectively.

In contrast, the other responses describe different aspects of neural communication but do not accurately define an action potential. Neurotransmitters play a role in synaptic transmission, sensory neurons carry signals from sensory receptors, and internal communication methods for the brain involve various pathways and networks, but all these functions are separate from the specific phenomenon of an action potential traveling along an axon.