Sympathetic components in left and right human cervical vagus nerve: implications for vagus nerve stimulation

Cervical vagus nerve stimulation is in a great variety of clinical situations indicated as form treatment. It textbook knowledge that at the cervical level contains many different fiber classes. Yet, recently, several reports have shown this also may contain an additional class potentially noradrenergic fibers, suggested to denote efferent sympathetic fibers. As such, nature and presence these fibers should be considered when choosing protocol. We studied human material extracted from dissection room cadavers order further confirm study their origin direction within determine distribution variability between subjects pairs left right nerves same individual. Sections were with immunohistochemical techniques using antibodies against tyrosine hydroxylase (TH: presumed indicate fibers), myelin basic protein neurofilament. Our results show least part TH-positive derive superior ganglion or trunk, do not follow cranial but take peripheral course through nerve. The portion highly variable individuals can distribute wander throughout fascicles maintain generally clustered appearance. fraction diminishes moving caudal remains more constant These help optimal parameters for settings.