A neurochemical is an organic molecule that participates in neural activity. This term is often used to refer to neurotransmitters and other molecules such as neuro-active drugs that influence neuron function Norepinephrine, dopamine, and serotonin were examples of neurochemicals. o GABA is an example of an inhibitory neurotransmitter. o Dopamine is another example of a neurotransmitter. It plays a key role in the functioning of the limbic system, which is involved in emotional function and control. o Serotonin plays a regulatory role in mood, sleep, and other areas. o Acetylcholine assists motor function.