Neurons fire

• A. stronger when there is a strong stimulus.
• B. either full strength or not at all.
• C. partially when there is a weak stimulus.
• D. partially when there is a strong stimulus.

Answer: (B)

Verified step by step guidance

1. Understand the concept of the 'all-or-none' principle in neural firing, which states that a neuron either fires at full strength or not at all.
2. Recognize that the strength of a stimulus does not affect the strength of the action potential; instead, it affects the frequency of firing.
3. Identify that a strong stimulus can cause neurons to fire more frequently, but each individual action potential remains at full strength.
4. Consider that a weak stimulus may result in fewer action potentials, but each one is still at full strength.
5. Conclude that neurons do not fire partially; they either fire completely or not at all, regardless of the stimulus strength.