From: drarwingnuttephd@gmail.com   
      
   Gut Bacteria Might Guide The Workings Of Our Minds   
   by ROB STEIN   
   November 18, 2013 3:07 AM ET   
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   Illustration by Benjamin Arthur for NPR   
      
      
      
   Could the microbes that inhabit our guts help explain that old idea of "gut   
   feelings?" There's growing evidence that gut bacteria really might influence   
   our minds.   
      
   "I'm always by profession a skeptic," says Dr. Emeran Mayer, a professor of   
   medicine and psychiatry at the University of California, Los Angeles. "But I   
   do believe that our gut microbes affect what goes on in our brains."   
      
   Mayer thinks 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. "It opens up a completely new way of looking at   
   brain function and health and    
   disease," he says.   
      
   So Mayer is working on just that, doing MRI scans to look at the brains of   
   thousands of volunteers and then comparing brain structure to the types of   
   bacteria in their guts. He thinks he already has the first clues of a   
   connection, from an analysis of    
   about 60 volunteers.   
      
   Mayer found that the connections between brain regions differed depending on   
   which species of bacteria dominated a person's gut. That suggests that the   
   specific mix of microbes in our guts might help determine what kinds of brains   
   we have -- how our    
   brain circuits develop and how they're wired.   
      
       
   Credit: Benjamin Arthur for NPR   
   Of course, this doesn't mean that the microbes are causing changes in brain   
   structure, or in behavior.   
      
   But other researchers have been trying to figure out a possible connection by   
   looking at gut microbes in mice. There they've found changes in both brain   
   chemistry and behavior. One experiment involved replacing the gut bacteria of   
   anxious mice with    
   bacteria from fearless mice.   
      
   "The mice became less anxious, more gregarious," says Stephen Collins of   
   McMaster University in Hamilton, Ontario, who led a team that conducted the   
   research.   
      
   It worked the other way around, too -- 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.   
      
   While no one's sure which foods are good for our microbiomes, eating more   
   veggies can't hurt.   
   The Salt   
   Can We Eat Our Way To A Healthier Microbiome? It's Complicated   
   To find out what might be causing the behavior changes, Collins and his   
   colleagues then measured brain chemistry in mice. They found changes in a part   
   of the brain involved in emotion and mood, including increases in a chemical   
   called brain-derived    
   neurotrophic factor, which plays a role in learning and memory.   
      
   Scientists also have been working on a really obvious question -- how the gut   
   microbes could talk to the brain.   
      
   A big nerve known as the vagus nerve, which runs all the way from the brain to   
   the abdomen, was a prime suspect. And when researchers in Ireland cut the   
   vagus nerve in mice, they no longer saw the brain respond to changes in the   
   gut.   
      
   "The vagus nerve is the highway of communication between what's going on in   
   the gut and what's going on in the brain," says John Cryan of the University   
   College Cork in Ireland, who has collaborated with Collins.   
      
   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.   
      
   "I'm actually seeing new neurochemicals that have not been described before   
   being produced by certain bacteria," says Mark Lyte of the Texas Tech   
   University Health Sciences Center in Abilene, who studies how microbes affect   
   the endocrine system. "These    
   bacteria are, in effect, mind-altering microorganisms."   
      
   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.   
      
   Knight (left) and Bucheli take soil samples from beneath one of the   
   decomposing bodies.   
   Shots - Health News   
   Could Detectives Use Microbes To Solve Murders?   
   One group of scientists has tested mice that have behaviors similar to some of   
   the symptoms of autism in humans. The idea is that the probiotics might   
   correct problems the animals have with their gastrointestinal systems --   
   problems that many autistic    
   children also have.   
      
   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.   
      
   "The idea is that these probiotic treatments may alter what we call the   
   microbiome and then may contribute to an improvement of psychiatric symptoms,"   
   says Faith Dickerson, director of psychology at the Sheppard Pratt Health   
   System.   
      
   "It makes perfect sense to me," says Leah, a study participant who has been   
   diagnosed with bipolar disorder. She agreed to talk with NPR if we agreed not   
   to use her full name. "Your brain is just another organ. It's definitely   
   affected by what goes on in    
   the rest of your body."   
      
   It's far too soon to know whether the probiotic has any effect, but Leah   
   suspects it might. "I'm doing really well," she says. "I'm about to graduate   
   college, and I'm doing everything right."   
      
   Mayer also has been studying the effects of probiotics on the brain in humans.   
   Along with his colleague Kirsten Tillisch, Mayer gave healthy women yogurt   
   containing a probiotic and then scanned their brains. He found subtle signs   
   that the brain circuits    
   involved in anxiety were less reactive, according to a paper published in the   
   journal Gastroenterology.   
      
   But Mayer and others stress that a lot more work will be needed to know   
   whether that probiotic -- or any others -- really could help people feel less   
   anxious or help solve other problems involving the brain. He says, "We're   
   really in the early stages."   
      
   microbiome   
   microbes   
   bacteria   
   mental health   
      
   http://www.npr.org/blogs/health/2013/11/18/244526773/gut-bacteri   
   -might-guide-the-workings-of-our-minds   
      
      
      
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