Final answer:
The amplitude of an EPSP is related to the change in the postsynaptic membrane potential caused by the binding of neurotransmitters to receptors on the postsynaptic membrane.
Step-by-step explanation:
In a neuron, the postsynaptic membrane potential refers to the electrical potential inside the postsynaptic cell membrane after receiving a synaptic signal. The amplitude of an excitatory postsynaptic potential (EPSP) is related to the change in the postsynaptic membrane potential caused by the binding of neurotransmitters to receptors on the postsynaptic membrane. A larger EPSP amplitude indicates a greater depolarization of the membrane potential, bringing it closer to the threshold for generating an action potential.