Final answer:
The correct answer is E) B and C, as presynaptic facilitation increases the probability of synaptic transmission leading to the depolarization of neurons and can be modified through synaptic plasticity associated with learning and conditioning.
Step-by-step explanation:
Presynaptic facilitation refers to the process by which synaptic transmission is made more efficient, increasing the likelihood that the postsynaptic neuron will fire an action potential. This facilitation typically results from an increase in the amount of neurotransmitter released into the synaptic cleft, often due to prolonged depolarization of the presynaptic neuron membrane, or by the insertion of additional receptors on the postsynaptic membrane, making it more sensitive to neurotransmitters.
Therefore, presynaptic facilitation typically enhances the synaptic function and is associated with long-term potentiation (LTP), a mechanism of synaptic plasticity where repeated activation strengthens synaptic connections. This stands in contrast to hyperpolarization, which inhibits action potential creation by making the inside of the neuron more negative, therefore moving the membrane potential away from the action potential threshold.
In summary, the main answer to the question is option E) B and C: presynaptic facilitation makes a pathway more likely to be in use through depolarization of selected neurons and capable of alteration through training and conditioning.