Final answer:
A change in the potential across a neuron's membrane is turned into a signal that is sent down the axon through a process called depolarization and generation of an action potential.
Step-by-step explanation:
When a neurotransmitter binds to receptors located on a neuron's dendrites, it opens ion channels in the dendrite's plasma membrane. This allows sodium ions to enter the neuron, causing depolarization of the membrane. If the depolarization reaches the threshold of excitation, an action potential is generated, which is a self-propagating reversal of the resting membrane potential. This action potential then travels down the axon, triggering the release of neurotransmitters at the axon terminal to transmit the signal to the next neuron.