Effect of Electrical Stimulation of the Nucleus of the Solitary Tract on Electroencephalographic Spectral Power and the Sleep-Wake Cycle in Freely Moving Cats

Background: The nucleus of the solitary tract (NTS) plays a determinant role in the antiepileptic effects of vagus nerve stimulation (VNS). One mechanism underlying the efficacy of VNS is the induction of cortical changes, detected by electroencephalogram (EEG), which can be mediated by the NTS through its projections to the cerebral nuclei responsible for modulating cortical activity. The effect of the electrical stimulation of the nucleus of the solitary tract (ENTS) on EEG activity and sleep states in freely moving animals is unknown. Objective: This study aims to analyze the effects of ENTS on the EEG spectral power and sleep-wake cycle in freely moving cats. Method: EEG was performed on the left amygdala and both pre-frontal cortices for 23 hours under baseline conditions and with ENTS in freely moving cats. The changes induced by ENTS on the EEG spectral power and the architecture of the sleep-wake cycle were analyzed. Results: ENTS increased the theta and beta band power for 12 hours. Furthermore, an increase in wakefulness occurred in the first six hours, followed by an increase in the total time of rapid eye movement (REM) sleep. Conclusion: ENTS produces a long-lasting increase in the theta and beta band power, which favors wakefulness and REM sleep in freely moving cats. (C) 2016 Elsevier Inc. All rights reserved.