Figure 1.
Experimental design. In a repeated-measures, cross-over design (A), participants attended two fMRI sessions in which they were exposed to a mild visual stress task (B) before and after exhalatory- (e-RAVANS) or inhalatory-gated (i-RAVANS) transcutaneous auricular vagus nerve stimulation (C). All subjects completed three runs (6 min each) of the mild visual stress task before and after RAVANS. Each run consisted of 12 blocks, 4 each of neutral (low arousal/neutral valence), negative (high arousal/negative valence) IAPS images and fixation stimuli (Fourier transforms of neutral images). Each block consisted of six different images, each presented for 5 seconds. During the stimulation period, 4 scan runs (6:30 min each) were collected.