Figure 4: Left and Right tcVNS produce equivalent activation of the vagus nerve and neck muscles.
a) tcVNS of the left and right branches of the vagus nerve produce comparable activation of the HB reflex. b) Similarly, no difference in muscle activation was observed between left and right tcVNS. c-e) There is no difference in the muscle activation thresholds, vagus activation thresholds, or the ratio between the two for left and right tcVNS. * denotes intensities at which the mean response significantly differed from zero.