Brain signaling depends heavily on neurotransmitters—simple molecules rapidly manufactured from nutrients in human diets. Let us take a closer look at the most common neurotransmitters.
The most widespread neurotransmitter in the brain, glutamate—a nonessential amino acid (building block of protein) and as much food for your brain as for the rest of your body—supports the construction and maintenance of neural connections and is, therefore, relevant to research on learning and memory. It is an excitatory neurotransmitter, stimulating—rather than inhibiting—neurons. Too much of it may be the cause of certain forms of epilepsy.
Researchers working on depression know about serotonin and its relation to mood and feelings of well-being. Axons from the raphe nuclei in the reticular formation of the brainstem release mood-altering serotonin to the entire cortex. Clinically depressed patients sometimes have low serotonin levels, which can be boosted with serotonin reuptake inhibitors. Mysteriously, although these boost serotonin levels within hours, it may take days for a patient to feel any lift. As is often the case with psychoactive drugs, they typically work for a period and the depression may come back once the brain gets used to them. Serotonin is not only mood-altering but also involved in memory, sleep, and cognition.