Left–right synchronicity of vagal spikes and their coordination with peripheral and cortical activity in rats

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The vagus nerve (VN) serves as a major communication pathway between the brain and peripheral organs. The left and right VN exhibit asymmetric structures and are considered to sense diverse peripheral organ states. However, it remains unknown how coordinately the left and right VN generate physiological spike activity. Here, we performed simultaneous electrophysiological recordings of left and right cervical VN spike patterns in rats. During non-movement periods, ongoing spike activity in both VNs was predominantly organized into burst events. The occurrence timing of burst events was partially synchronized between the left and right VN, whereas individual spike timing within burst events showed no pronounced synchronization. Under anesthetized conditions, VN spike activity was not strongly entrained to oscillatory gastric or intestinal motility on a cycle-by-cycle basis but pharmacological enhancement of gastrointestinal activity was sufficient to induce bilaterally synchronized burst events in a pattern closely resembling that observed under freely moving conditions. During VN burst events in non-movement periods, prefrontal cortical local field potential power across the wide frequency range was substantially modulated, suggesting a functional link between vagal afferent activity and higher-order brain dynamics. Taken together, these findings advance our insight into VN-mediated brain–body interactions.