Questions: Which term refers to the period of time after a nerve cell has responded to a stimulus in which it cannot be excited by a threshold stimulus? Inhibitory period Refractory period Latent period Excitatory period

The answer is the second one (or B): the refractory period.

Explanation for each option:

• Inhibitory period: This term is not typically used to describe the period after a nerve cell has responded to a stimulus. It generally refers to a period when a neuron is less likely to fire due to inhibitory signals.
• Refractory period: This is the correct term. It refers to the period of time after a nerve cell has responded to a stimulus during which it cannot be excited by a new threshold stimulus. This period ensures that the nerve cell has time to reset before it can be activated again.
• Latent period: This term refers to the time between the application of a stimulus and the beginning of the response. It does not describe the period after the response.
• Excitatory period: This term is not used to describe the period after a nerve cell has responded to a stimulus. It generally refers to a period when a neuron is more likely to fire due to excitatory signals.

Summary: The term that refers to the period of time after a nerve cell has responded to a stimulus in which it cannot be excited by a threshold stimulus is the refractory period.