Gut Bacteria Affect the Brain

Rambo Tribble writes "John Cryan, a researcher at the University College Cork, explains the relationship between the bacteria in your gut and your brain. 'In a pioneering study, a Japanese research team showed that mice raised without any gut bacteria had an exaggerated physical response to stress, releasing more hormone than mice that had a full complement of bacteria. However, this effect could be reduced in bacteria-free mice by repopulating their gut with Bifidobacterium infantis, one of the major symbiotic bacteria found in the gut. Cryan’s team built on this finding, showing that this effect could be reproduced even in healthy mice.' It seems the flora in your intestines can influence brain development as well as aspects of health and nutrition, which in turn affect such things as hormones and neurotransmitters. 'His team tested the effects of two strains of bacteria, finding that one improved cognition in mice. His team is now embarking on human trials, to see if healthy volunteers can have their cognitive abilities enhanced or modulated by tweaking the gut microbiome.'"

Comments

Morality questions

[DoofusOfDeath]

I know I'm not the first person to think of this, but...

The more external influences we see on brain function, the less sure I am of how appropriate it is to hold people responsible for their actions.

For example, if child molestation is something one is predisposed to after being molested as a child, what's a just punishment if/when that person him/herself goes on to molest? Or, in this case, if ones gut bacteria makes on prone to certain behaviors, for example stress --> violence (not sure that's right, but just for the sake of discussion), should we hold every to persons equally accountable for having a violent reaction?

Re:We are a colony organism

[Samantha Wright]

As someone who does this stuff for a living, I'd argue the contrary—that the weight ratio is misleading, because it's an exception. In terms of RNA and protein-coding genes, isoforms, homologues, and selection rates, in addition to more obvious things like number of cells, they vastly outstrip the core of the body. Think also of how much more time they've cumulatively had to evolve and swap genes!

The best analogy for this, I think, is a *nix distro—the human genome is a monolithic kernel, and the bacteria are all the shell scripts and daemons that help manage it.