Figure 5.

Proposed mechanism of bifidobacteria-mediated effects on host neurodevelopmental processes. In this proposed model, bifidobacteria down-regulate early expression of synapse-related genes in the host CNS. Additionally, bifidobacteria are important for the early reactive functionality of microglia, which prevent excess synapse formation during this critical window. This process promotes effective refinement of the developing synaptic network and potentiation of appropriate contacts, leading to circuit maturation. Functional organization of neural circuitry leads to synchronicity of firing and typical behavioral phenotypes.