@article{vanrheede.23,
	title={Cortical signatures of sleep are altered following effective deep brain stimulation for depression},
	author={van Rheede, J.J., and Alagapan, S. and Denison, T. and  Riva-Posse, P. and  Rozell, C. and  Mayberg, H. and  Waters, A.C. and  Sharott, A.},
	year= 2023,
	month = jun,
	abstract = {High-frequency deep brain stimulation (DBS) of the subcallosal cingulate cortex (SCC) is an experimental therapy for treatment-resistant depression (TRD). Recent studies have shown that chronic SCC DBS leads to long-term changes in the electrophysiological dynamics meas- ured from local field potential (LFP) during wakefulness. However, it is unclear if the changes extend to electrophysiological markers of sleep. This is a crucial gap in knowledge, given the link between depression and sleep disturbances, and an emerging interest in the interaction between circadian rhythms and chronic DBS. To address this gap, we analysed two key electrophysiological signatures of sleep – slow-wave activity (SWA, 0.5-4.5Hz) and sleep spindles – in LFP recorded from SCC using state-of-art implantable devices with recording capabilities. All 9 participants in this cohort responded to treatment, allowing us to compare the electro- physiological changes before and after 24 weeks of therapeutically effective SCC DBS. SWA power was highly correlated between hemispheres, consistent with a global sleep state. Furthermore, SWA occurred earlier in the night after 24 weeks of chronic DBS and had a more prominent peak time of occurrence. While we found no evidence for changes to slow wave power or stability, we found an increase in the density and amplitude of sleep spindles. Our results represent the first-of-its-kind report on long-term electrophysiological markers of sleep recorded from SCC in patients with depression. We provide evidence of earlier sleeping and increased sleep spindle activity following successful DBS treatment for depression. Future work is needed to establish the causal relationship between long-term DBS and the neural mechanisms underlying sleep.},
	note={Under review.}
}