Our emotional behavior is influenced by ... intestinal microbes?

Intestinal microbes that live in the human digestive system exist not only to help digest food or cause stomach pain in the event of any disturbance. Scientific research suggests that these small creatures, forming in their intestines a kind of own world, significantly affect human behavior, including potentially can regulate how it reacts to fear.

The connection between the stomach and the brain

A new study conducted by a group of scientists from the University of California at Los Angeles seems to have revealed another rather strange connection between the stomach and the brain. Namely, intestinal bacteria, most likely, interact with those areas of the brain that are responsible for the mood and general behavior of a person. It is interesting that for the first time such a mechanism was found in healthy people.

According to previous studies, the emotional responses that were observed in rodents (including those associated with anxiety and depression) may vary depending on the microbiota of the intestine, but this relationship has not been proven in humans until now.

Features of the study of American scientists

A team of scientists collected fecal samples from 40 different women to study bacteria living in their intestines. Then the same women were connected to the magnetic resonance imaging (MRI) scanner and showed them various photos of people, environments, situations or objects that were supposed to provoke the emotional reactions of the participants.

According to data published in the journal Psychosomatic Medicine, scientists have discovered the existence of two primary groups of bacteria, which seem to be capable of exerting some influence on brain function.

How do bacteria of the first group

The bacterium Prevotella was found in seven women in the study group. The study of the brain of these participants showed the relationship between the visual, emotional and sensory areas of it, while their hippocampus was less active. Recall that the hippocampus is a region of the brain associated with consciousness, emotional regulation and the transformation of short-term memories into long-term memories.

Scientists suggest that these women, after looking at images with negative scenes, experience strong negative emotions (including those associated with anxiety).

How the brain is affected by bacteria of the second group

Bacterioids, which the researchers ranked as the second bacterial group, were more common among the remaining 33 women. Consequently, the work of their brain was different from that which was characteristic of the representatives of the first group. The frontal cortex and islet fraction - brain regions that are responsible for solving problems and complex information processing, had more gray matter than the other group of women. Their hippocampus was also more voluminous and active.

These participants, unlike women who were in the first group, were much less likely to experience negative emotions when they looked at images with negative scenes.

It is too early to draw conclusions ...

This study is undoubtedly of interest, but, as with most similar studies, it simply proves the existence of a strong correlation between the intestinal microbiome and cognitive functions. However, scientists have not been able to determine the cause-and-effect mechanisms.