So at negative 70 millivolts. Now, let's suppose we apply a stimulus onto the cell membrane of the neuron. And this stimulus is equal to, or it exceeds the threshold value, which is around, usually around negative 45 millivolts. So the threshold's value is basically the value of the stimulus that has to be just right so that the action potential is generated. So once we reach our threshold value, this threshold voltage of about negative 45 millivolts will signal the voltage gated sodium channels to actually open up. And as soon as they open up, our sodium ions will begin to flow.