Stimulation positions at the auricle. Stimulations were performed at two positions of the external ear respectively. The ta-VNS was marked as two red dots. The tan-VNS was marked as two blue dots. For stimulation, bipolar sliver electrodes were attached to the skin with cathode on the position marked as “a”, and anode on the position marked as “b”.
He et al. BMC Neuroscience 2013 14:85 doi:10.1186/1471-2202-14-85