What occurs during repolarization of a neuron?

During repolarization of a neuron, the membrane potential of the cell returns to a more negative value after depolarization. This process primarily involves the movement of potassium ions. When a neuron is excited and reaches the threshold to fire an action potential, sodium channels open, allowing sodium ions to flow into the cell, causing depolarization. Following this phase, the sodium channels close, and potassium channels open, permitting potassium ions to flow out of the cell.

The efflux of potassium results in the restoration of the negative resting membrane potential. This is essential for preparing the neuron to be capable of firing another action potential in the future, thereby allowing the neuron to reset its membrane potential after the excitatory phase of the action potential. Therefore, the movement of potassium ions out of the cell is a critical and defining characteristic of the repolarization phase.