What signifies the end of depolarization in a neuron?

The end of depolarization in a neuron is signified by the closure of voltage-gated sodium channels and the opening of voltage-gated potassium channels. During depolarization, sodium ions influx into the cell through opened sodium channels, causing the membrane potential to become more positive. As depolarization reaches its peak, the sodium channels begin to close, stopping the influx of sodium ions. Simultaneously, the voltage-gated potassium channels open in response to the change in membrane potential.

This opening of potassium channels allows potassium ions to flow out of the neuron, which is the primary mechanism for repolarization. The movement of potassium ions out of the cell restores the negative charge inside the neuron, thus signaling the end of the depolarization phase. The closure of sodium channels prevents further sodium entry, while the opening of potassium channels initiates the repolarization process.

Other choices focus on aspects of the action potential but do not directly address the termination of the depolarization phase as comprehensively as the correct answer does. For instance, repolarization is the consequence of the events initiated by the closure of sodium channels and the opening of potassium channels, and while returning to the resting membrane potential is a subsequent phase, it follows after depolar