Treatment of mice with Mycobacterium vaccae, a ‘friendly’ bacterium found in soil, activates a group of neurones that produce the brain chemical serotonin. The lack of serotonin in the brain is thought to cause depression in people, thus M. vaccae‘s effects on the behavior of mice may be due to increasing the release of serotonin in parts of the brain that regulate mood.
“These studies help us understand how the body communicates with the brain and why a healthy immune system is important for maintaining mental health. They also leave us wondering if we shouldn’t all be spending more time playing in the dirt.” ~ Dr Chris Lowry.
Interest in the project arose after human cancer patients being treated with the bacteria Mycobacterium vaccae unexpectedly reported increases in their quality of life.