So at negative 70 millivolts. And at this point, the inside of the cell, this region, will contain a negative charge. The outside will contain a positive charge. Now, we know that outside of the cell, we have a higher concentration of sodium ions than on the inside of the cell. So as soon as our stimulus reaches our threshold value, that will open up our sodium, our sodium voltage gated channels. And when they open up, this is known as our depolarization period.