<prompt> Post-tetanic facilitation is thought to be the result of which of the following?Opening of voltage-gated sodium channelsOpening of transmitter-gated potassium channelsA buildup of calcium in the presynaptic terminalElectrotonic conduction  <response>: Post-tetanic facilitation is the neuronal phenomenon in which a neuron is more easily excited after a brief period of activity. This phenomenon is thought to be due to the buildup of calcium in the presynaptic membrane caused by the prior neuronal activity. Subsequent neuronal impulses release neurotransmitter more readily as a result of this preplaced calcium from the prior stimulus. 