Does the brain listen to the gut?

Abstract

Transplanting gut bacteria from one mouse strain to another can override genetics and change behavior.

Keywords: behavior; brain; gut; microbiome; mouse; myelin; neuroscience; psychiatry.

Figure 1.. Mouse-based experiments provide further support for the idea that the gut microbiome can influence the brain and behavior.

Gacias et al. divided NOD mice into four groups, with each group receiving a different treatment (top). Only mice that received the oral control showed a change in behavior. These mice were less social and showed more "despair-like behaviors". These mice also had reduced myelination in the medial prefrontal cortex (this region’s location in the brain is shown with a blue dot). The gut microbiomes in these mice also became enriched with bacteria called Bacteroidetes and Firmicutes. Oral antibiotics didn’t affect behavior, but did reduce the diversity of the gut microbiome. Injections (control or antibiotics, right) had no effects.

Figure 2.. Altering the gut microbiome can trigger behavioral changes.

Gacias et al. transplanted the gut microbiome (via fecal transplants) from oral-control NOD mice into B6 mice. The B6 mice had first had their own gut microbiome depleted with antibiotics, and the recipient mice showed similar changes in behavior as the donors. As before, the blue dot indicates the location of the medial prefrontal cortex in the brain.