Final answer:
The binding of a neurotransmitter causes spatially local changes in membrane voltage by opening ligand-gated ion channels on the postsynaptic membrane.
Step-by-step explanation:
The binding of a neurotransmitter causes spatially local changes in membrane voltage. When a specific neurotransmitter binds to ligand-gated ion channels on the postsynaptic membrane, it causes these channels to open. This allows ions, such as Na+ or K+, to flow into or out of the postsynaptic cell, resulting in changes in the membrane voltage. For example, the binding of acetylcholine at the neuromuscular junction causes Nat channels to open, leading to depolarization of the postsynaptic membrane.