In short, we still lack mechanistic understanding of the roles of vagal sensory neurons in the microbiota-gut-brain axis, calling for more cell-type specific ablation studies in the future

Accumulating evidence is suggesting that the vagus nerve is one of the major routes in the microbiome-gut-brain axis

The gastrointestinal (GI) tract is home to ~500 million enteric neurons, ~70% of the body’s immune cells, and over 100 trillion microbes

In particular, serotonin can activate vagal afferents via serotonin receptor HTR3A [7], and therefore, may serve as a major signaling molecule between gut microbiota and the vagus nerve

about two-thirds of enteroendocrine cells are able to make synapses with adjacent nerves

it has been shown that numerous brain regions are impacted by vagus nerve stimulation, and this connectivity has been termed the “vagus afferent network”.