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

We are a colony organism

[RichMan]

We are 90% bacteria. It is time we stopped viewing ourselves as a monlithic organism and started viewing ourselves as some sort of managed colony.
http://www.npr.org/templates/s...

"We think that there are 10 times more microbial cells on and in our bodies than there are human cells. That means that we're 90 percent microbial and 10 percent human. There's also an estimated 100 times more microbial genes than the genes in our human genome. So we're really a compendium [and] an amalgamation of human and microbial parts."

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.

Re:We are a colony organism

[cold fjord]

...the human genome is a monolithic kernel, and the bacteria are all the shell scripts and daemons that help manage it.

So what you're telling me is essentially that the viability of myself and any offspring is going to depend on a massive collection of perl scripts. Lovely. I'm forked. :(

Re:We are a colony organism

[rmdingler]

My gut tells me you're onto something here.

Machines

[i kan reed]

I don't think I mind being an extraordinary complex machine functioning to protect the interests of very simple organisms incapable of thinking for themselves. But that might just be my bacterial overlords talking.

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:Morality questions

[danlip]

Independent of this, there is a moral question of "should we be punishing people?" The alternative is to focus on deterrence, rehabilitation, and protecting society. "Protecting society" could justify locking someone away for ever (if the justice system determines there is no chance of rehabilitation). "Rehabilitation" could include altering their microbiome if we figure out how, or it could just be psychological work. Punishment is government administered revenge - it may provide some deterrence, but it's not particularly good at it. But modern justice systems still focus almost entirely on punishment.