Elena Renken writes:

Our brains may seem physically far removed from our guts, but in recent years, research has strongly suggested that the vast communities of microbes concentrated in our digestive tract open lines of communication between the two. The intestinal microbiome has been shown to influence cognition and emotion, affecting moods and the state of psychiatric disorders, and even information processing. But how it could do so has been elusive.

Until recently, studies of the gut-brain relationship have mostly shown only correlations between the state of the microbiome and operations in the brain. But new findings are digging deeper, building on research that demonstrates the microbiome’s involvement in responses to stress. Focusing on fear, and specifically on how fear fades over time, researchers have now tracked how behavior differs in mice with diminished microbiomes. They identified differences in cell wiring, brain activity and gene expression, and they pinpointed a brief window after birth when restoring the microbiome could still prevent the adult behavioral deficits. They even tracked four particular compounds that may help to account for these changes. While it may be too early to predict what therapies could arise once we understand this relationship between the microbiome and the brain, these concrete differences substantiate the theory that the two systems are deeply entwined.

Pinning down these mechanisms of interaction with the brain is a central challenge in microbiome research, said Christopher Lowry, an associate professor of integrative physiology at the University of Colorado, Boulder. “They have some tantalizing leads,” he added.

Coco Chu, the new study’s lead author and a postdoctoral associate at Weill Cornell Medicine, was intrigued by the concept that microbes inhabiting our bodies could affect both our feelings and our actions. Several years ago, she set out to examine these interactions in fine-grained detail with the help of psychiatrists, microbiologists, immunologists and scientists from other fields. [Continue reading…]