Final answer:
The time during which auditory nerve fibers cannot fire the next action potential is called the absolute refractory period. During this period, the voltage-gated sodium channels in the neuron are inactivated and unable to open. A stronger stimulus is required to initiate a new action potential after the refractory period.
Step-by-step explanation:
The time during which auditory nerve fibers cannot fire the next action potential is known as the absolute refractory period. This is a brief period immediately following the transmission of an impulse, in which a neuron regains its ability to transmit another impulse.
During the absolute refractory period, the voltage-gated sodium (Na+) channels are inactivated and cannot be opened. Once the channels are back to their resting conformation, a new action potential could be initiated, but only by a stronger stimulus than the one that initiated the previous action potential.