Multi-scale disruption of sleep-related cortical activity following ischemic lesions
Sleep plays a critical role in neuroplasticity related processes of learning and memory consolidation. Moreover, its importance in recovery after stroke is known. Yet, how ischemic lesions affect the sleep-wake cycle (SWC) neural dynamics remains poorly explored, with most studies not addressing the multi-scale extent of this pathology effects in brain function. Here, we performed chronic wideband electrophysiological recordings in behaving rats to investigate ischemic stroke impact in the primary motor cortex on SWC organization in connected, non-lesioned, areas of the sensorimotor loop. We combined behavioral assessment with multi-scale analyses spanning global SWC architecture, network level events of privileged functional reshaping during sleep, and single-unit activity. Lesioned animals, exhibiting sharp motor impairments, displayed clear alterations of SWC macro-architecture, including reduced latency to slow-wave sleep and correlations between spectral features and motor asymmetry. At meso-scale, ischemia disrupted the physiological coordination between slow oscillations and spindles, and the latter showed shift in spectral power distribution during intermediate sleep. In contrast, units firing and coupling with spindles were largely preserved. These findings reveal that ischemia perturbs the fine coordination of sleep-related processes across scales stage-specifically. The study lays solid evidence to be possibly leveraged for innovative protocols of neurorehabilitation targeting privileged windows of neuroplasticity.