From a fascinat ing
Scientific American article:
Regardless of how these intestinal “guests” exert their influence, these studies suggest that brain-directed behaviors, which influence the manner in which
animals interact with the external world, may be deeply influenced by that animal’ s relation
ship with the microbial organisms living in its gut.
And the discovery that gut bacteria exert their influence on the brain within a discrete
developmental stage may have important implications for developmental
brain disorders.