A consistent topic I talk about is how important the microbiome of our gut is to our very being.
According to new research, the bacteria in our digestive systems may help mold brain structure as we're growing up, and possibly influence our moods, behavior and feelings when we're adults.
In mice, bold mice became timid when they got the microbes of anxious ones. And aggressive mice calmed down when the scientists altered their microbes by changing their diet, feeding them probiotics or dosing them with antibiotics.
A big nerve known as the vagus nerve, which runs all the way from the brain to the abdomen, was a prime suspect in how the bacteria communicates with the brain. And when researchers cut the vagus nerve in mice, they no longer saw the brain respond to changes in the gut.
Gut microbes may also communicate with the brain in other ways, scientists say, by modulating the immune system or by producing their own versions of neurotransmitters.
This research raises the possibility that scientists could someday create drugs that mimic the signals being sent from the gut to the brain, or just give people the good bacteria — probiotics — to prevent or treat problems involving the brain.
In the mice, many of their autism behaviors were no longer present or strongly ameliorated with probiotics, says Paul Patterson at the California Institute of Technology in Pasadena, Calif. His research will be published soon in the journal Cell.
Experiments to test whether changing gut microbes in humans could affect the brain are only just beginning.
One team of researchers in Baltimore is testing a probiotic to see if it can help prevent relapses of mania among patients suffering from bipolar disorder.