Fig. 1

In vivo data acquisition, stimulation parameter design, and outcomes quantification. A Schema of vagus nerve stimulation (VNS) showing cuff implantation site on the right cervical vagus nerve and two wire electrodes placed under the thyroid cartilage to measure EMG (adapted from (Tabler et al. 2017) under the Creative Commons Attribution License). B VNS parameters. “Amplitude”: stimulation amplitude of symmetric biphasic pulse (300 μs per phase) normalized to bradycardia threshold (BCT). “Mean Pulse Rate”: number of pulses applied per burst for 1 s repeating patterns (e.g., 10 pulses/s, 5 pulses/s). “Frequency”: intra-burst frequency of pulses (e.g., 40 Hz, 20 Hz). C Illustrative data from single trial (1.0xBCT, 20 Hz constant frequency). ECG (top) used to quantify heart rate (HR, middle). EMG collected from same trial (bottom). VNS begins at t = 10 s and ends at t = 40 s (red bar). D Stimulation artifact removal using template subtraction and quantification of VNS-evoked EMG. Template subtraction was performed to remove stimulus artifact (left). Stimulus was applied at 1 ms and trigger signal was used to identify time-course of pulse (yellow dashed line at left). Second-wave (starting at 2.5 ms) was identified as VNS-evoked EMG. Rectified EMG quantified using average rectified value (EMG_ARV, red dashed) during window of EMG waveform (right, red shading)