AQA Biopsychology Exam 2025 – 400 Free Practice Questions to Pass the Exam

Inhibitory potential refers to changes in the neuron's membrane potential that make it less likely for the neuron to fire an action potential. This inhibitory effect typically occurs when neurotransmitters bind to receptors on the postsynaptic membrane, causing hyperpolarization, which increases the negativity of the inside of the neuron relative to the outside. This hyperpolarization makes it harder for the neuron to reach the threshold needed to trigger an action potential, thus inhibiting neuronal firing.

In contrast, excitatory potentials promote the likelihood of action potential firing by depolarizing the membrane, while an action potential itself refers to the rapid depolarization and repolarization that occur during neuronal firing. Resting potential is the state of the neuron when it is not actively firing and is usually stable, but does not actively inhibit firing; instead, it maintains a baseline state. Therefore, the concept of inhibitory potential directly aligns with the inhibition of neuronal firing.