Last year, we put out a podcast called "The Power of Poop," which looked at the use of fecal transplants (a.k.a. "transpoosions") to treat everything from multiple sclerosis to Parkinson's disease. A fascinating Scientific American article explores how gut bacteria may have even further-reaching functions:
In the past few years scientists have been discovering that these microscopic inhabitants of our body may be subtly altering our moods, emotions and perhaps even our personalities. Gut microbiota appear to alter gene activity in the brain and the development of key regions involved in memory and learning. These denizens of our intestines could help explain why psychiatric symptoms vary among individuals, as well as their responses to medications. Gut microbes could also account for some of the differences in mood, personality and thought processes that occur within and among individuals.
(HT: Market Design)