ALL OR NOTHING PRINCIPLE

• WHAT ARE ALL ACTION POTENTIALS?

  same size
• WHAT DOES THE ALL OR NOTHING PRINCIPLE STATE?

  there is a threshold value that the stimulus must meet to trigger an action potential

  -> if it is below threshold = no action potential

  -> if it is above threshold = action potential
• HOW IS THE STRENGTH OF A STIMULUS DETERMINED IF ALL ACTION POTENTIALS STAY THE SAME SIZE?

  • number of impulses in a given time
  • different neurones having different thresholds