This article from Science NOW is a year old, but fascinating. More and more we're seeing how our bodies are not so much machine as ecologies, how critical gut bacteria are to our health. At the same time we're leaning more about how parasitic and symbiotic organisms can affect the nervous system and the mind and emotions. If bacteria in our guts, or Toxoplasma gondii in our brains, can affect our behavior and attitude, it's yet more evidence for the physical origin of consciousness. Mind-Altering Bugs - ScienceNOW
To further investigate the mind-altering potential of benign bacteria, Cryan and colleagues at McMaster University in Canada fed mice a broth containing a benign bacterium, Lactobacillus rhamnosus. The scientists chose this particular bug partly because they had a handy supply and also because related Lactobacillus bacteria are a major ingredient of probiotic supplements and very little is known about their potential side effects, Cryan says. In this case, the side effects appeared to be beneficial. Mice whose diets were supplemented with L. rhamnosus for 6 weeks exhibited fewer signs of stress and anxiety in standard lab tests, Cryan and colleagues report online today in the Proceedings of the National Academy of Sciences. For example, the rodents spent more time exploring narrow elevated walkways and wide-open spaces, which are scary to rodents, and they exhibited a smaller spike in stress hormone levels when the researchers put them in water. "This was really exciting because it tells us the animals are more chilled out and don't mount the same stress response," Cryan says.