from wsj: What you think is going on in your head may be caused in part by what's happening in your gut. A growing body of research shows the gut affects bodily functions far beyond digestion. Studies have shown intriguing links from the gut's health to bone formation, learning and memory and even conditions including Parkinson's disease. Recent research found disruptions to the stomach or intestinal bacteria can prompt depression and anxiety - at least in lab rats. Better understanding the communication between the gut and the brain could help reveal the causes of and treatments for a range of ailments, and provide diagnostic clues for doctors.