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The effects of acute, short-term visual deprivation on low-frequency EEG activity during wakefulness and sleep

Bernardi, Giulio and Betta, Monica and Cataldi, Jacinthe and Leo, Andrea and Ricciardi, Emiliano and Haba-Rubio, J. and Pietrini, Pietro and Heinzer, R. and Siclari, Francesca The effects of acute, short-term visual deprivation on low-frequency EEG activity during wakefulness and sleep. In: World Sleep 2017, 7-11 October 2017, Prague (Submitted)

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Introduction: experimental evidence indicates that regional changes in slow-wave activity (SWA, 0.5-4.5 Hz) during NREM-sleep, and in theta activity (5-9 Hz) during wakefulness may reflect local variations in sleep need induced by recent experience-dependent brain plasticity1. However, such evidence is mainly based on studies involving the sensorimotor domain. Previous attempts to extend these findings to a purely sensory system –such as the visual system– provided contradictory results. To clarify this issue, here we evaluated the effects of short-term visual deprivation on low-frequency EEG activity during wakefulness and sleep. Materials and Methods: twelve healthy volunteers (25.5±3.7 yrs, 6 M) participated to two experimental sessions (order counterbalanced across participants), each lasting from ~2.30 pm to ~8.30 am of the following day: a visual deprivation (VD) condition, during which subjects were blindfolded, and a visual stimulation (VS) condition. All activities were rigorously regulated: in VD, subjects had to listen to audiobooks for ~6 h, while in VS they watched movies for a similar amount of time. All participants slept for ~7.5 h (11.30 pm – 7.00 am), while their brain activity was recorded using high-density (hd-)EEG (256 electrodes). Brief test sessions including an auditory psychomotor vigilance test (aPVT) and Likert-scales for sleepiness, alertness and mood were completed every 2 h and ~40 min after awakening. Three 2 min eyes closed hd-EEG recordings were obtained before and after sleep to investigate potential variations in local theta power. Mean SWA, slow wave density and amplitude6 were calculated for the first 20 min of NREM-sleep. Statistical analyses (paired t-tests) were restricted to an occipital and a centro-frontal region of interest (ROI). Results: relative to VS, VD was associated with reduced N1 and REM latency and with increased REM duration and proportion (p < 0.05). No differences were observed in other sleep parameters. No significant differences between VS and VD were observed in aPVT reaction time, subjective sleepiness, alertness and mood either before or after sleep. In eyes-closed wake recordings before sleep, occipital (but not frontal) theta power was higher after VS than after VD (p < 0.03; ~11.00 pm) and this difference disappeared after a night of sleep (p > 0.23; ~8.00 am). During the first 20 min of NREM-sleep, SWA and slow wave amplitude showed no significant differences across experimental condition. However, the density of occipital (but not frontal) slow waves tended to be higher in VS (p = 0.09). Additional analyses showed that small (amplitude < 30 µV), occipital (but not large and/or frontal) slow waves were significantly more numerous after VS than after VD (p < 0.02). Discussion: short-term visual deprivation is associated with an occipital decrease in theta activity during wakefulness, and in the density of small, local slow waves during NREM-sleep, likely reflecting local, experience-related changes in cortical plasticity. However, in contrast to previous observations involving the sensorimotor domain, sleep SWA and slow wave amplitude showed no clear changes, suggesting that important regional differences may exist with respect to the morphology of slow waves and their relation to experience-dependent modifications.

Item Type: Conference or Workshop Item (Speech)
Subjects: R Medicine > R Medicine (General)
Research Area: Computer Science and Applications
Depositing User: Monica Betta
Date Deposited: 05 Sep 2017 06:41
Last Modified: 05 Sep 2017 06:41
URI: http://eprints.imtlucca.it/id/eprint/3781

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