Mark Morningstar, DC, PhD
Neurotransmitters are the chemicals by which the brain controls nearly every function in the body. These chemicals vary in their locations, amounts, and functions. Many of these neurotransmitters vary their amounts even over the course of one day. For example, melatonin decreases from morning to midday as we wake up, then steadily increases again as it gets closer to nighttime. Melatonin is the neurotransmitter that make us tired and helps us fall asleep. Other neurotransmitters like gamma-amino-butyric acid (GABA) act on the emotional centers of the brain to make us happy. When levels of the neurotransmitters are deficient, excessive, or abnormally fluctuate, neurological or neuropsychological symptoms may result.