1 INTRODUCTION Vagus nerve stimulation (VNS) appears to modify neurochemistry and promote adaptive changes within the brain (Badran et al., 2017; Kaniusas et al., 2019). Preclinical evidence has shown that VNS influences the release of neurotransmitters, including norepinephrine, acetylcholine, serotonin, and gamma-aminobutyric acid (GABA) (Badran et al., 2017; Cheyuo et al., 2011; Frazer et al., 2014; Groves & Brown, 2005; Hulsey et al., 2019; Nichols et al., 2011).