Scientist Do intestinal bacteria control the brain?

Microbes from the gut affect the brain and behavior

Neurobiologists say: microbes from the gut affect brain and behavior. They could cross the blood-brain barrier and migrate from the gut to the brain via nerves.

Excitement at the Neuroscience Society
The annual meeting of the Neuroscience Society is usually quiet and is of interest to neurobiologists themselves. But this time, spectacular theses were so startling that even the magazines Science and Nature wrote about it.

Bacteria colonize our intestines and allow them to digest food. Researchers now want to have bacteria detected in the brain. (Image: pixeljack / fotolia.com)

From the bowels to the center
The team around neuroanatomin Rosalinda Roberts assumes that intestinal microbes invade the brain, helping to shape human behavior. They could cross the blood-brain barrier, reach the brain via nerve tracts and be neither traumatized nor infected.

Body full of bacteria
Human bodies are full of microbes in various species and different populations. Some harm us and cause illness, others enable us to live. They settle in the vagina as well as in the lungs, in the mouth and in the intestine.

The microbiome
Researchers now speak of the microbiome as a supplement to the genome. Thus, man consists not only of his "own" genes, but also of "his" microbes, which contain much more cells and genetic information than the human body in which they move.

Intestinal microbes organize the digestion
The best research is the microbiome in the gut. Here live various forms of bacteria. These enable digestion and maintain the immune system.

Feeling - from the intestine to the brain
If we speak of a "gut feeling" in the vernacular, then we are right. The microbiome in the gut affects our feelings, moods and thoughts in direct communication with the brain.

Gut-brain axis
Scientists call this compound the intestinal brain axis. In the experiment, mice that got a gut microbiome from bolder mice also became bolder.

Is the brain affected??
So far, researchers have suggested that the intestinal flora and brain share information, but that signals from the brain are based on biochemical processes.

The blood-brain barrier
In the body there is the so-called blood-brain barrier. This prevents potential pathogens from getting into the brain from the blood. If microbes such as fungi, parasites or bacteria penetrate the brain, for example as a result of an injury, this can quickly lead to deadly consequences.

Microbes in the brain?
The researchers around Rosalinda Roberts discovered bacteria in 34 cases in the brains of the dead in varying numbers.

What are the microbes??
These were bacteria with a nucleus in rod form, with DNA, ribosomes and vacuoles.

Blood-brain barrier particularly populated
In the brains of humans, but also of mice, the bacteria sat in the hippocampus, in the prefrontal cortex, in the substantia nigra, in astrocytes and glial cells, but especially at the blood-brain barrier.

No infection?
The researchers emphasize that the bacteria did not reach the body through an intervention after death. The deceased had not previously suffered from infections that could explain the bacteria. This indicates that the bacteria live regularly in the brain.

The same bacteria as in the gut
Even more. The proteobasteries, Firmicutes and Bacteroidetes in the brain are the same as in the intestine. The microbial worlds in the gut and brain are possibly closely linked.

How did the microbes get to the brain??
How the bacteria got into the brain, the researchers do not answer clearly. They suspect that this could have gone over the blood.

Brain bacteria control our behavior?
Intestinal bacteria significantly affect intestinal activity. But what about the microbes in the brain? Are our perceptions, our thoughts, our brain functions co-determined by microscopic creatures? That sounds like science fiction and is waiting for further research. (Dr. Utz Anhalt)