• Bashar W Badran, Logan T Dowdle, Oliver J Mithoefer, Nicholas T LaBate, James Coatsworth, Joshua C Brown, William H DeVries, Christopher W Austelle, Lisa M McTeague, and Mark S George.
• Department of Neuroscience, Medical University of South Carolina, Charleston, SC, 29425, United States; Department of Psychiatry, Medical University of South Carolina, Charleston, SC, 29425, United States; Department of Psychology, University of New Mexico, Albuquerque, NM, 87131, United States; US Army Research Lab, Aberdeen Proving Ground, MD, 21005, United States. Electronic address: badran@musc.edu.
• Brain Stimul. 2018 May 1; 11 (3): 492-500.

BackgroundElectrical stimulation of the auricular branch of the vagus nerve (ABVN) via transcutaneous auricular vagus nerve stimulation (taVNS) may influence afferent vagal networks. There have been 5 prior taVNS/fMRI studies, with inconsistent findings due to variability in stimulation targets and parameters.ObjectiveWe developed a taVNS/fMRI system to enable concurrent electrical stimulation and fMRI acquisition to compare the effects of taVNS in relation to control stimulation.MethodsWe enrolled 17 healthy adults in this single-blind, crossover taVNS/fMRI trial. Based on parameters shown to affect heart rate in healthy volunteers, participants received either left tragus (active) or earlobe (control) stimulation at 500 μs 25 HZ for 60 s (repeated 3 times over 6 min). Whole brain fMRI analysis was performed exploring the effect of: active stimulation, control stimulation, and the comparison. Region of interest analysis of the midbrain and brainstem was also conducted.ResultsActive stimulation produced significant increased BOLD signal in the contralateral postcentral gyrus, bilateral insula, frontal cortex, right operculum, and left cerebellum. Control stimulation produced BOLD signal activation in the contralateral postcentral gyrus. In the active vs. control contrast, tragus stimulation produced significantly greater BOLD increases in the right caudate, bilateral anterior cingulate, cerebellum, left prefrontal cortex, and mid-cingulate.ConclusionStimulation of the tragus activates the cerebral afferents of the vagal pathway and combined with our review of the literature suggest that taVNS is a promising form of VNS. Future taVNS/fMRI studies should systematically explore various parameters and alternative stimulation targets aimed to optimize this novel form of neuromodulation.Copyright © 2017 Elsevier Inc. All rights reserved.

23 keywords...

hide…