1 The threshold potential of most neurons is a depolarization to about -55mV or more. A depolarization to less than -55mV has no effect on the creation of an action potential less effect than a depolarization to the threshold more effect on the creation of an action potential the same effect as a depolarization to the threshold Clear my selection Multiple Choice 1 point

The correct answer is **less effect than a depolarization to the threshold**.<br /><br />Here's why:<br /><br />* **Threshold Potential:** The threshold potential is the critical level of depolarization a neuron must reach to trigger an action potential. Think of it as the "all-or-none" point. If the depolarization reaches the threshold (typically around -55mV), an action potential is generated and travels down the axon.<br /><br />* **Subthreshold Depolarization:** A depolarization that doesn't reach the threshold potential (-55mV in this case) will cause some change in membrane potential, but it won't be enough to open the voltage-gated sodium channels responsible for the rapid depolarization phase of the action potential. The neuron will partially depolarize, but it will return to its resting state without firing an action potential. These smaller depolarizations are called graded potentials.<br /><br />* **All-or-None Principle:** Action potentials follow the all-or-none principle. They either happen fully or not at all. A stronger stimulus doesn't create a "bigger" action potential; it simply increases the *frequency* of action potentials.<br />