Figure 1 –

(A) Experimental setup for data collection: fMRI data were collected with partial brain coverage focused on the brainstem (group-consistent coverage shown). Concurrently to fMRI, electrocardiography (ECG) and respiration signals were monitored, and the latter was used to trigger in real-time the onset of respiration-gated left auricular stimulation, delivered through custom electrodes placed either in the cymba conchae (RAVANS taVNS runs) or over the earlobe (greater auricular nerve control, GANctrl). (B) Example respiratory traces showing timing for exhalation-gated RAVANS (eRAVANS), inhalation-gated RAVANS (iRAVANS), and exhalation-gated GANctrl stimulation, counterbalanced across subjects. (C) Stimulation parameters (number of events, inter-stimulus interval (ISI), current) and ratings were not significantly different across conditions. Error bars represent SD.