Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter. When GABA binds to specific receptors on the postsynaptic membrane, it causes ligand-gated potassium channels to open. This results in the facilitated diffusion of positively charged potassium ions (K+\text{K}^+K+) out of the postsynaptic neurone.
Explain how the movement of K+\text{K}^+K+ ions out of the postsynaptic neurone inhibits the generation of an action potential in this neurone.