The effect of body contouring surgery on weight loss maintenance following bariatric surgery

Introduction: Vagus Nerve Stimulation (VNS) is currently a neurosurgical management for medication-resistant epilepsy.In animal studies, VNS can activate cholinergic networks.Cholinergic projections are mainly received from the Pedunculopontine Nucleus (PPN) or the Nucleus Basalis of Meynert (NBM).Cholinergic dysfunction is implicated in symptoms of neurodegenerative disorders.Cholinergic activity can be assessed electrophysiologically using Prepulse Inhibition (PPI) and Short Latency Afferent Inhibition (SAI).Aim: To investigate whether VNS can access human cholinergic networks.Method: Twenty subjects were recruited in a double-blinded randomised control trial.SAI involved median nerve stimulation preceding transcranial magnetic stimulation of the motor cortex at various interstimulus intervals (ISI).PPI incorporated median nerve stimulation before supraorbital nerve stimulation at several ISIs.Electromyograms were recorded from first dorsal interosseous and orbicularis oculi muscles.Non-invasive VNS (nVNS) and placebo sham intervention were delivered to the right vagus nerve.Results: nVNS increased inhibitory effects of SAI significantly when compared with placebo stimulation (P ¼ 0.011).The significant effect was only seen in the SAI-PPI trial order subgroup (P ¼ 0.021).nVNS had no significant effect on PPI.Conclusion: nVNS can modulate cholinergic pathways in humans.The dissociation between PPI and SAI suggests nVNS effects are likely to be mediated via the NBM.