The afferent vagus nerve transmits ascending information regarding internal physiological states of the visceral organs, so-called interoception, to the brain. Recent studies have suggested that vagal interoceptive signals exert prominent impacts on emotional states such as anxiety and depression. While the significance of vagal-brain communications has been realized, basic research issues remain regarding whether and to what extent vagal afferent signals underpin brain neurophysiological activity that affects emotion. To address these issues, we recently developed a method to record spiking patterns from the cervical vagus nerve using a cuff–shaped electrode while simultaneously monitoring local field potential (LFP) signals from the medial prefrontal cortex (PFC) and the amygdala of mice. After identifying the relationship between vagus nerve activity and PFC-AMY LFP patterns at specific frequency bands, we examined how these vagal-brain interactions are altered by chronic stress loads. In addition, we tested whether these pathophysiological brain states can be restored by VNS that replicates VN sustained spike patterns identified from non-pathological states. These observations provide new insight for uncovered issues regarding the physiological dynamics of the vagus nerve.