Gut Feelings? Maternal Separation, Microbiota, and Mood — in Mice

Intestinal microbiota appear to communicate with the central nervous system, influencing brain and behavior via endocrine, immune, and neural pathways. In mice, early alterations in intestinal microbiota produce shifts in hippocampal and amygdala neurohumoral processes and behavioral patterns; for example, germ-free mice exhibit fewer anxiety-like behaviors. Because early traumatic experiences influence gastrointestinal functioning and shape aspects of behavior later in life, investigators asked whether such adversity might affect intestinal microbiota, eventually altering behavior.

Mice were either germ-free or conventional and either separated from mothers when young (which reliably generates behavioral abnormalities) or typically raised. …