IMT Institutional Repository: No conditions. Results ordered -Date Deposited. 2024-03-28T14:02:38ZEPrintshttp://eprints.imtlucca.it/images/logowhite.pnghttp://eprints.imtlucca.it/2016-01-28T11:37:59Z2017-08-04T10:18:57Zhttp://eprints.imtlucca.it/id/eprint/3032This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/30322016-01-28T11:37:59ZSleep reverts changes in human gray and white matter caused by wake-dependent trainingAbstract Learning leads to rapid microstructural changes in gray (GM) and white (WM) matter. Do these changes continue to accumulate if task training continues, and can they be reverted by sleep? We addressed these questions by combining structural and diffusion weighted {MRI} and high-density {EEG} in 16 subjects studied during the physiological sleep/wake cycle, after 12 h and 24 h of intense practice in two different tasks, and after post-training sleep. Compared to baseline wake, 12 h of training led to a decline in cortical mean diffusivity. The decrease became even more significant after 24 h of task practice combined with sleep deprivation. Prolonged practice also resulted in decreased ventricular volume and increased {GM} and {WM} subcortical volumes. All changes reverted after recovery sleep. Moreover, these structural alterations predicted cognitive performance at the individual level, suggesting that sleep's ability to counteract performance deficits is linked to its effects on the brain microstructure. The cellular mechanisms that account for the structural effects of sleep are unknown, but they may be linked to its role in promoting the production of cerebrospinal fluid and the decrease in synapse size and strength, as well as to its recently discovered ability to enhance the extracellular space and the clearance of brain metabolites.Giulio BernardiLuca Cecchettiluca.cecchetti@imtlucca.itFrancesca SiclariAndreas BuchmannXiaoqian YuGiacomo HandjarasMichele BellesiEmiliano Ricciardiemiliano.ricciardi@imtlucca.itSteven R. KecskemetiBrady A. RiednerAndrew L. AlexanderRuth M. BencaMaria Felice GhilardiPietro Pietrinipietro.pietrini@imtlucca.itChiara CirelliGiulio Tononi2015-11-10T10:32:22Z2016-09-13T09:43:21Zhttp://eprints.imtlucca.it/id/eprint/2859This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/28592015-11-10T10:32:22ZNeural and Behavioral Correlates of Extended Training during Sleep Deprivation in Humans: Evidence for Local, Task-Specific EffectsRecent work has demonstrated that behavioral manipulations targeting specific cortical areas during prolonged wakefulness lead to a region-specific homeostatic increase in theta activity (5–9 Hz), suggesting that theta waves could represent transient neuronal OFF periods (local sleep). In awake rats, the occurrence of an OFF period in a brain area relevant for behavior results in performance errors. Here we investigated the potential relationship between local sleep events and negative behavioral outcomes in humans.Volunteers participated in two prolonged wakefulness experiments (24 h), each including 12 h of practice with either a driving simulation (DS) game or a battery of tasks based on executive functions (EFs). Multiple high-density EEG recordings were obtained during each experiment, both in quiet rest conditions and during execution of two behavioral tests, a response inhibition test and a motor test, aimed at assessing changes in impulse control and visuomotor performance, respectively. In addition, fMRI examinations obtained at 12 h intervals were used to investigate changes in inter-regional connectivity.The EF experiment was associated with a reduced efficiency in impulse control, whereas DS led to a relative impairment in visuomotor control. A specific spatial and temporal correlation was observed between EEG theta waves occurring in task-related areas and deterioration of behavioral performance. The fMRI connectivity analysis indicated that performance impairment might partially depend on a breakdown in connectivity determined by a “network overload.”Present results demonstrate the existence of an association between theta waves during wakefulness and performance errors and may contribute explaining behavioral impairments under conditions of sleep deprivation/restriction.Giulio BernardiFrancesca SiclariXiaoqian YuCorinna ZennigMichele BellesiEmiliano Ricciardiemiliano.ricciardi@imtlucca.itChiara CirelliMaria Felice GhilardiPietro Pietrinipietro.pietrini@imtlucca.itGiulio Tononi