Microbial Brain Transplant?
In the decade since Brain Plague, extraordinary revelations have come out on how microbes control the mind. A recent article in PNAS reports how Lactobacillus bacteria in the digestive tract of mice decreased stress and anxiety behaviors. The bacteria were associated with increased neurotransmitter expression in the hippocampus area of the brain, among other brain effects. But how could digestive bacteria affect the brain? The effect actually involves the vagus nerve, a major nerve that connects the digestive tract with the brain.
If bacteria can control rodent behavior, why not humans? The brain regions involved affect memory and learning as well as mood. Other microbes, such as the parasite Toxoplasma, are suspected of controlling human brains ways that encourage spread of the parasite–with possibly more horrific effects. (Caveat, the last source is new to me; perhaps Paws4thot knows if it’s any good?) Data on toxoplasmosis are taken seriously by researchers, as are the possible connections with schizophrenia.
But intestinal bacteria are our friends–actually, part of us. For all we know, we’ll find out that intestinal bacteria are a normal “part of our brain,” just as fecal bacteria are part of our intestine. Last summer at Renovation I reported on fecal transplant, a miracle cure for C. diff and ulcerative colitis. Next, will we be treating psychiatric disorders with gut bacteria?