In addition to the known signaling molecules in the brain (acetylcholine, glutamate, GABA, dopamine, norepinephrine, serotonin), 35 types of neurochemicals (signaling molecules) have been identified as effective in the brain. These signaling molecules primarily mediate the regulation of learning, memory, and behavioral functions. The relationships of these signaling molecules with the gut microbiota are being investigated. It is possible to obtain entirely new information on this subject in the future. In fact, the roles of the gut microbiota in regulating brain functions are understood to be much more than just the tip of the iceberg, in light of current findings.

For example, Galanin is a signaling molecule related to memory, or Orexins are signaling molecules related to memory, behavior, and cognitive skills (perception, comprehension, learning ability). The relationships of dozens of signaling molecules like this with the gut microbiota have been studied and researched in neuropsychiatric problems such as autism, Attention Deficit Disorder (ADD), Attention Deficit Hyperactivity Disorder (ADHD), anxiety, and depression, which often accompany autism. The relationships between the balance of gut microbiota and the balance of signaling molecules in the brain have been explained in numerous scientific articles.

Below is a list of some of the important neurochemicals related to memory, cognitive skills and behavior (*).

*Choudhury A, Tripti Sahu T, Ramanujam PL et al. (2018) Neurochemicals, behaviours and psychiatric perspectives of neurological diseases. Neuropsychiatry (London); 8(1):395-424.

DOI:   10.4172/Neuropsychiatry.1000361.