What occurs during an action potential in neurons?

During an action potential, there is a critical change in the electrical charge of the neuron, which is primarily driven by the activity of sodium and potassium ions. When a neuron is stimulated past its threshold, voltage-gated sodium channels open, allowing sodium ions to rush into the cell. This influx of positively charged sodium ions depolarizes the membrane, creating a rapid increase in voltage.

As the membrane potential reaches its peak, the sodium channels close, and voltage-gated potassium channels open. Potassium ions then flow out of the neuron, causing repolarization, where the membrane potential returns to a negative value. This sequence of depolarization followed by repolarization constitutes the action potential.

Thus, the process specifically involves the active transport of sodium and potassium ions across the neuron's membrane, which is essential for the propagation of electrical signals along neurons and enables communication within the nervous system. This ion exchange is foundational to how neurons operate and transmit signals, making it the correct answer.