Vagus nerve stimulation (VNS) is increasingly considered for the treatment of intractable epilepsy and holds potential for the management of a variety of neuropsychiatric conditions. The emergence of the field of connectomics and the introduction of large-scale modeling of neural networks has helped elucidate the underlying neurobiology of VNS, which may be variably expressed in patient populations and related to responsiveness to stimulation. In this report, the authors outline current data on the underlying neural circuitry believed to be implicated in VNS responsiveness in what the authors term the "vagus afferent network." The emerging role of biomarkers to predict treatment effect is further discussed and important avenues for future work are highlighted.
Keywords: BDNF = brain-derived neurotrophic factor; BOLD = blood oxygenation level dependent; DRN = dorsal raphe nucleus; EEG = electroencephalography; FGF = fibroblast growth factor; GABA = gamma-aminobutyric acid; IL = interleukin; LC = locus coeruleus; NTS = nucleus tractus solitarius; PBN = parabrachial nucleus; SSEP = somatosensory evoked potential; VNS; VNS = vagus nerve stimulation; epilepsy; fEPSP = field excitatory postsynaptic potential; fMRI = functional MRI; neuromodulation; vagus nerve stimulation.