Editing Threshold potential (section)

===Depolarization===
However, once a stimulus activates the voltage-gated sodium channels to open, positive sodium ions flood into the cell and the voltage increases. This process can also be initiated by ligand or neurotransmitter binding to a [[Ligand-gated ion channel|ligand-gated channel]]. More sodium is outside the cell relative to the inside, and the positive charge within the cell propels the outflow of potassium ions through delayed-rectifier voltage-gated potassium channels. Since the potassium channels within the cell membrane are delayed, any further entrance of sodium activates more and more voltage-gated sodium channels. Depolarization above threshold results in an increase in the conductance of Na sufficient for inward sodium movement to swamp outward potassium movement immediately.{{sfn|Nicholls|Martin|Fuchs|Brown|2012|p=121}} If the influx of sodium ions fails to reach threshold, then sodium conductance does not increase a sufficient amount to override the resting potassium conductance. In that case, [[subthreshold membrane potential oscillations]] are observed in some type of neurons. If successful, the sudden influx of positive charge depolarizes the membrane, and potassium is delayed in re-establishing, or hyperpolarizing, the cell. Sodium influx depolarizes the cell in attempt to establish its own equilibrium potential (about +52 mV) to make the inside of the cell more positive relative to the outside.