The gut-brain axis (GBA) is a bidirectional communication between the brain (central nervous system, or CNS) and the gut (gastrointestinal system, or GI). Cognitive and emotional systems in the CNS can influence gut function and environment, and vice versa, the GI environment can influence CNS-controlled cognitive and emotional systems, such as mood and behavior. Studies have shown that inflammatory bowel disease (IBD) patients are at higher risk for developing mood disorders, such as depression and anxiety. The gut microenvironment, consisting of a collection of microbes, microbial-derived metabolites, and host-associated cells and their responses, is thought to have a major impact on IBD-associated development of mood disorders, particularly depression and anxiety. Our lab investigates how changes in the gut microenvironment might influence brain function, with special emphasis on development of mood and behavioral disorders.