What happens to neurons during the all-or-none response?

During the all-or-none response, neurons operate under a principle where once a certain threshold of stimulation is reached, they will fire an action potential fully, or not fire at all. This means that the action potential is not a graded response; there is no middle ground. The firing is an all-or-nothing event.

When a neuron receives a stimulus that is strong enough to reach the threshold, voltage-gated sodium channels open, resulting in a rapid influx of sodium ions and the generation of an action potential. This process occurs in a uniform manner; it does not vary in strength. If the stimulus does not reach the threshold, the neuron will remain at rest and not fire.

This contrasts with other potential outcomes suggested in the incorrect choices. For instance, if there is variability in the strength of the response or if the neuron may not fire based on the stimulus, it would not align with the all-or-none principle. Neurons must reach a specific threshold to trigger the full response, emphasizing the consistency of the firing mechanism once that threshold is met.