So basically what happens is this is the resting membrane potential of about negative 70 millivolts. This is our threshold value of about negative 45 millivolts. Now, if we apply stimulus onto the membrane of the neuron at the exxon hillock, and if the stimulus is equal to or exceeds this threshold value, then that will cause, that will signal the sodium voltage gated channels to actually open up. So at this point, they open up and this causes the depolarization of our membrane. So basically, as the sodium ions move down their electrochemical gradient and as they move into the cell, that causes the inside to go from negative to positive and the outside to go from positive to negative, as shown in this diagram. And that basically increases our cell voltage from negative 70 millivolts to about positive 45 millivolts.