Vagus nerve stimulation (VNS) is a treatment for epilepsy with an unknown mechanism of action. The role of the locus coeruleus and noradrenergic neurotransmission in VNS will be investigated using neurophysiological techniques, selective brain lesions and noradrenergic antagonists/agonists. Unraveling the mechanism of action of VNS could lead to the optimization of stimulation parameters and efficacy of the treatment.