RECONSTRUCTING VAGAL ANATOMY

With its large numbers of afferent (sensory) and efferent (motor) fibers, the vagus is the main conduit for bidirectional communication between the brain and visceral organs and participates in autonomic reflexes regulating cardiorespiratory, gastrointestinal, and neuroimmune functions. In the human vagus, nerve fibers are arranged in fascicles. Along the vagus, afferent and efferent fibers leave the fascicles and emerge from the nerve trunk to form branches, which in turn provide sensory and motor innervation to essentially all visceral organs in the neck, chest and abdomen. Even though much is known about the macroscopic and microscopic anatomy of the vagus, the spatial organization of fascicles and fibers within the nerve, as it relates to the innervated organs and the sensory and motor functions of the vagus, is largely unknown. The spatial organization of fibers in the human vagus has implications for vagus neuromodulation therapies. The overall objective of this proposal is to create and share with the scientific community a quantified map of the fascicular and microscopic structure and the organ connectivity of the human vagus nerve, from the brainstem to the abdominal region, with several cross-registered layers of anatomical information at the organ branch, fascicle, and single fiber level.