What change occurs in a neuron during depolarization?

During depolarization, the membrane potential of a neuron becomes more positive. This process occurs as a result of sodium ions (Na+) flowing into the neuron through voltage-gated sodium channels. When a stimulus reaches a certain threshold, these channels open, allowing Na+ to enter the cell. As sodium rushes in, the inside of the neuron becomes less negative or, more accurately, moves toward a positive value, leading to a change in the membrane potential. This change is crucial for the generation of an action potential, which is essential for the transmission of nerve signals.

The movement of the membrane potential toward a more positive value distinguishes depolarization from other states, such as hyperpolarization, where the membrane potential becomes more negative, or resting conditions, where it remains stable. Understanding this change is fundamental to the physiology of neurons and how they communicate within the nervous system.