Final answer:
The inhibitory postsynaptic potential (IPSP) is more difficult for a neuron to respond to compared to the excitatory postsynaptic potential (EPSP) because it hyperpolarizes the neuron, moving the membrane potential away from the threshold necessary for firing an action potential.
Step-by-step explanation:
When considering the responsiveness of the postsynaptic potential, the inhibitory postsynaptic potential (IPSP) is typically more difficult to respond to than the excitatory postsynaptic potential (EPSP). The reason is that an IPSP hyperpolarizes the neuron, making it less likely to achieve the threshold required to fire an action potential. In contrast, an EPSP depolarizes the neuron, moving the membrane potential closer to the threshold, thus making the neuron more likely to generate an action potential.
In the context of synaptic transmission, the integration of EPSPs and IPSPs plays a crucial role in determining the overall excitability of the neuron. If multiple EPSPs occur simultaneously or in close succession (a process known as summation), they can collectively bring the neuron's membrane potential to the threshold, triggering an action potential. However, if IPSPs are also present, they can negate the effects of the EPSPs, preventing the neuron from firing an action potential by moving the membrane potential further from the threshold.