Cognitive abilities are impaired by sleep deprivation and can be recovered when sufficient sleep is obtained. Changes in alpha-band oscillations are considered to be closely related to sleep deprivation. In this study, power spectrum, source localization and functional connectivity analyses were used to investigate the changes in resting-state alpha-band activity after normal sleep, sleep deprivation and recovery sleep. The results showed that the global alpha power spectrum decreased and source activation was notably reduced in the precuneus, posterior cingulate cortex, cingulate gyrus, and paracentral lobule after sleep deprivation. Functional connectivity analysis after sleep deprivation showed a weakened functional connectivity pattern in a widespread network with the precuneus and posterior cingulate cortex as the key nodes. Furthermore, the changes caused by sleep deprivation were reversed to a certain extent but not significantly after one night of sleep recovery, which may be due to inadequate time for recovery sleep. In conclusion, large-scale resting-state alpha-band activation and functional connectivity were weakened after sleep deprivation, and the inhibition of default mode network function with the precuneus and posterior cingulate cortex as the pivotal nodes may be an important cause of cognitive impairment. These findings provide new insight into the physiological response to sleep deprivation and determine how sleep deprivation disrupts brain alpha-band oscillations.

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Most studies on the effects of light exposure have been conducted with continuous light. The present study investigated the effects of intermittent light exposure on sleepiness, mood, electroencephalographic activity during sleep and performance the next morning. Fifteen volunteers were scheduled to come to the sleep laboratory to experience different lighting conditions: intermittent bright light, continuous bright light and continuous dim light. Subjective sleepiness and mood were assessed during light exposure, with electroencephalographic recording during sleep. After waking the next morning, participants filled out questionnaires and went through two cognitive tasks. The results revealed significantly lower ratings of sleepiness after intermittent light exposure, which is not different from the ratings in the continuous bright light condition, and an increase in vitality during later part of the evening and more beta activity during the first 90 minutes of sleep in the intermittent light condition, in comparison with the continuous dim light condition. However, both intermittent and continuous bright light exposure showed no difference from the continuous dim light condition in subjects' mood and cognitive functioning the next morning. The data indicated intermittent light during evening decreased sleepiness, had only minimal impact on mood in the evening, increased beta electroencephalographic activity during sleep, but had no significant influence on cognitive functioning the next morning.

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BackgroundCognitive abilities are impaired by sleep deprivation and can be recovered when sufficient sleep is obtained. Changes in alpha-band oscillations are considered to be highly related to sleep deprivation. The effect of sleep deprivation on brain activation and functional connectivity in the resting-state alpha band remains unclear. The purpose of this study was to investigate how sleep deprivation and recovery sleep could change resting-state alpha-band neural oscillations.MethodsIn this study, thirty young, healthy participants obtained approximately 8 h of normal sleep, followed by 36 h of sleep deprivation. On the following recovery night, subjects underwent recovery sleep. Resting-state EEG after normal sleep, sleep deprivation and recovery sleep was recorded. Power spectrum, source localization and functional connectivity analyses were used to investigate the changes in resting-state alpha-band activity after normal sleep, sleep deprivation and recovery sleep.ResultsThe results showed that the global alpha power spectrum decreased and source activation was notably reduced in the precuneus, posterior cingulate cortex, cingulate gyrus, and paracentral lobule after sleep deprivation. Functional connectivity analysis after sleep deprivation showed a weakened functional connectivity pattern in a widespread network with the precuneus and posterior cingulate cortex as the key nodes. Furthermore, the changes caused by sleep deprivation were reversed to a certain extent but not significantly after one night of sleep recovery, which may be due to inadequate time for recovery sleep.ConclusionsIn conclusion, large-scale resting-state alpha-band activation and functional connectivity were weakened after sleep deprivation, and the inhibition of default mode network function with the precuneus and posterior cingulate cortex as the pivotal nodes may be an important cause of cognitive impairment. These findings provide new insight into the physiological response of sleep deprivation and determine how sleep deprivation disrupts brain alpha-band oscillations.