Neurotransmission in the CNS

There are four neurotransmitters that are tiny molecules. These are acetylcholine, dopamine, norepinephrine, and serotonin. These small molecule neurotransmitters play a role on its neural activation system that regulates huge parts in the brain (Kolb and Whishaw, 2006, p. 168-169). The cholinergic system uses acetylcholine as a transmitter and is involved in the electroencephalographic maintenance while awake. It is suggested that it plays part in memory by the way of neuron exitability. Impairments of cholinergic neurons is suggested to play a role in Alzheimer's disease, a neurodegenerative memory disorder.

The dopaminergic system uses dopamine as a neurotransmitter. It has a role in nigostriatal as well as mesolimbic pathways. In the nigrostriatal pathway it has a role in normal motor behavior and diminished dopamine in this path has been associated with Parkinson's disease, which is characterized by rigidity of the muscles and dyskinesias.

The noradrenergic system uses norepinephrine as a neurotransmitter and plays a role in emotion. Decreases and increases to this system are associated with depression and mania, respectively.

The seotonergic system uses serotonin as a neurotransmitter. Like acetylcholine it is also involved in the electroencelographic awake state. Serotonin activity alterations have been found to be associated with obsessive-compulsive disorder, vocal/motor tics. In addition it is thought to play also a role in schizophrenia. Serotonin decrements are associated with depression.