TY - JOUR TI - Non-invasive access to the vagus nerve and its projections in humans DO - https://doi.org/doi:10.7282/T3G73BZP PY - 2014 AB - The vagus nerve -- the main visceral nerve -- has a somatosensory auricular branch that innervates the external ear. The central projections of the auricular branch of the vagus nerve have not been reported on in humans. Therefore, the focus of this dissertation is to ascertain whether electrical stimulation of the external ear, in the sensory field of the auricular branch of the vagus nerve, activates the “classical” visceral vagus central projection sites in healthy men and women, and to characterize the regional brain activity elicited by cymba conchae stimulation. Mild electrical stimulation of the vagal sensory field in the cymba conchae of the left external ear activated “classical” vagal central projections, including the nucleus of the solitary tract, spinal trigeminal nucleus, parabrachial area, dorsal raphe, locus coeruleus, amygdala, and nucleus accumbens. Activation of the paracentral lobule of the cerebral cortex was also observed. Deactivations in response to the stimulation were observed in the hippocampus and hypothalamus. The activity within many of these areas was found to persist even after cessation of stimulation. Furthermore, there is a marked effect on the network among these areas during cymba conchae stimulation and after stimulation. These findings provide evidence that the central projections of the vagus nerve can be accessed non-invasively via the external ear in humans. The findings suggest a rational basis for the observed therapeutic anti-nociceptive, anti-depressive, and anti-convulsive effects of vagal stimulation. KW - Psychology KW - Vagus nerve KW - Labyrinth (Ear) LA - eng ER -