The neurobiology of gut feelings

“It’s a gut feeling.” Indeed, how and why do we get “gut feelings?” After the brain, the gut is the second most innervated bodily organ, diffusely interconnected with gastrointestinal afferent neurons. Whilst sensory neurons from the gut ascend by means of the spinal cord and vagal nerve to subcortical and higher cortical areas of the brain, caudally descending motor efferents from brain to gut seek to modulate gastrointestinal function. Such is the construct of the “brain–gut axis,” a bi-directional body nexus permitting constant information transfer between both brain and gut so as to provide us with visceral interoception. This chapter reviews the neurobiology of gut feelings and discuss their role in both physical and mental health and disease.