Bacteria are everywhere – including our bodies. This is not a bad thing as they help us in many ways. Many studies show that gut bacteria have an impact on behavior as well. During the first few months after birth, the brain actively develops. At the same time, bacteria enter from the diet and environment and multiply in the infants’ gut. As Bifidobacterium species (bifidobacteria) are the most common bacteria in the infants’ gut, we wanted to see if these bacteria play a role in the development of brain functions.
We examined the behavior of mice which we treated with bifidobacteria only and compared it to the behavior of mice without any bacteria and mice that had normal mouse gut bacteria. The germ-free mice showed many important behavioral differences when compared to mice with normal bacteria, and the mice that had only bifidobacteria behaved similarly to the normal mice demonstrating how important these bacteria are. The sex of the rodents also played an important role in whether bifidobacteria could change their behavior.