From Great Genetics To Neuropsychology – Outline Of The Research On The Association Between Microbiota And Human Behaviour

After the success of the Human Genome Project, which lead to estimating the number of human genes at only about 30–40 thousand, researchers started paying attention to a great number of genes present inside and on the surface of the human body. The gastrointestinal tract alone is a habitat for up to 1000 species of bacteria and other microorganisms. These microorganisms add a pool of 2–4 million additional genes. In 2009, a hypothesis was proposed that changes in microbiota are sensed by neurons localized along the entire bowel length, and communicated to the brain, making up the gut-brain axis. The vagus nerve seems to serve as the main communication path. Besides affecting gastrointestinal tract functions, primary neuropsychological studies show that gut microbiota is linked to HPA activity, and thus with arousal regulation and emotional functions. Research also suggests a link to cognitive functions. For now, mechanisms of those connections remain, for the most part, unknown. History of the research on human microbiota shows a complex nature of human functions and the need for integration of knowledge from, as it may seem, distant branches of science, like microbiology and psychology. While connections between microbiota and host organism remain unrecognized, our knowledge of human biology will be incomplete.

1. Human Genome Project. 2. In search for the missing genes. 3. Human Microbiome Project. 4. In search for the structure in infinity. 5. Gut-brain axis, towards neuropsychology. 6. Conclusions