behavioral transplants: tards are full of _______ - but there may be a simple solution...,

nature |  Twelve Canadian scientists accomplished something we've only heard about in science fiction: They transplanted a set of behaviors from one set of animals to another set of animals! And you'll never guess what part of these animals they physically transplanted to achieve this feat: It was not their brains; It was not their hearts; It was their gut-contents! We have all heard the phrase "you are what you eat", but scientists have discovered the real truth: You are what you poop. 

Science is rapidly discovering that the intestinal tract is a vast ecosystem of microbes and the proportion of each microbe species present doesn't just influence digestion, but also brain development, cognition and even behavior. This connection has been termed the microbiota-gut-brain axis and is a new and quickly growing area of research. Different strains of lab mice are known to have different personalities: Some are more anxious and skittish, while others are more easy-going and friendly. When scientists looked at the microbes in their guts, they found that anxious mice and easy-going mice had different proportions of these microbial species. Different microbe species seem to have different effects on their hosts. While some gut microbes can cause illness, mice that have been raised so that they have never had any gut microbes have all kinds of problems, including symptoms of irritable bowel syndrome (IBS), obsessive compulsive disorder (OCD), depression, and autism, suggesting that some microbe species are important for healthy brain functioning.

Stephen Collins of McMaster University and his research collaborators tested the effects of gut microbes on behavior by giving BALB/c mice either 7 days of oral antibiotics or water. BALB/c mice are a very timid and anxious mouse strain. Normally, BALB/c mice that are placed in a box that is half dark and half bright will prefer to spend more time hiding in the dark side. BALB/c mice placed on an elevated platform will hesitate and take a long time to step down to explore. After a week of antibiotic treatment, mice given the antibiotic had a different proportion of microbe species in their guts, spent more time in the bright side of the light-dark box and were quick to step down from the elevated platform to explore! The scientists also found brain changes in these mice that correspond to decreased anxiety. But when the mice were tested a second time two weeks after treatment, all effects were gone, likely because the gut microbes were able to repopulate and rebalance their ecosystems.