Final answer:
Neuromodulation that causes an IPSP results in hyperpolarization of the membrane potential, making it less likely for an action potential to be generated.
Step-by-step explanation:
Neuromodulation that causes an IPSP (inhibitory postsynaptic potential) would have the effect of hyperpolarization on a membrane potential.
For example, when the neurotransmitter GABA (gamma-aminobutyric acid) is released from a presynaptic neuron, it binds to and opens Cl- channels, causing Cl- ions to enter the cell and hyperpolarize the membrane. This makes the neuron less likely to fire an action potential.
Hyperpolarization in inhibitory postsynaptic potentials (IPSPs) moves the membrane potential away from the threshold, making it more difficult for an action potential to be generated.