Slow-wave sleep

About: Slow-wave sleep is a research topic. Over the lifetime, 6543 publications have been published within this topic receiving 320663 citations. The topic is also known as: deep sleep.

Targeted Memory Reactivation during Sleep Depends on Prior Learning.

Abstract: Study objectives When sounds associated with learning are presented again during slow-wave sleep, targeted memory reactivation (TMR) can produce improvements in subsequent location recall. Here we used TMR to investigate memory consolidation during an afternoon nap as a function of prior learning. Participants Twenty healthy individuals (8 male, 19-23 y old). Measurements and results Participants learned to associate each of 50 common objects with a unique screen location. When each object appeared, its characteristic sound was played. After electroencephalography (EEG) electrodes were applied, location recall was assessed for each object, followed by a 90-min interval for sleep. During EEG-verified slow-wave sleep, half of the sounds were quietly presented over white noise. Recall was assessed 3 h after initial learning. A beneficial effect of TMR was found in the form of higher recall accuracy for cued objects compared to uncued objects when pre-sleep accuracy was used as an explanatory variable. An analysis of individual differences revealed that this benefit was greater for participants with higher pre-sleep recall accuracy. In an analysis for individual objects, cueing benefits were apparent as long as initial recall was not highly accurate. Sleep physiology analyses revealed that the cueing benefit correlated with delta power and fast spindle density. Conclusions These findings substantiate the use of targeted memory reactivation (TMR) methods for manipulating consolidation during sleep. TMR can selectively strengthen memory storage for object-location associations learned prior to sleep, except for those near-perfectly memorized. Neural measures found in conjunction with TMR-induced strengthening provide additional evidence about mechanisms of sleep consolidation.

Napping and the selective consolidation of negative aspects of scenes.

Abstract: After information is encoded into memory, it undergoes an offline period of consolidation that occurs optimally during sleep. The consolidation process not only solidifies memories, but also selectively preserves aspects of experience that are emotionally salient and relevant for future use. Here, we provide evidence that an afternoon nap is sufficient to trigger preferential memory for emotional information contained in complex scenes. Selective memory for negative emotional information was enhanced after a nap compared to wakefulness in two control conditions designed to carefully address interference and time-of-day confounds. Although prior evidence has connected negative emotional memory formation to rapid eye movement (REM) sleep physiology, we found that non-REM delta activity and the amount of slow wave sleep (SWS) in the nap were robustly related to the selective consolidation of negative information. These findings suggest that the mechanisms underlying memory consolidation benefits associated with napping and nighttime sleep are not always the same. Finally, we provide preliminary evidence that the magnitude of the emotional memory benefit conferred by sleep is equivalent following a nap and a full night of sleep, suggesting that selective emotional remembering can be economically achieved by taking a nap.

Decreased sleep quality and increased sleep related movements in patients with Tourette's syndrome.

Abstract: OBJECTIVE—Sleep quality and movement patterns across sleep stages in patients with Tourette's syndrome were examined to determine the influence of syndrome severity on sleep quality and the differential effect of sleep stages on tic and non-tic movements. METHODS—Twenty five patients with Tourette's syndrome (mean age 29 (SD 7) years) and 11 control subjects (29 (5) years) were studied by polysomnography and simultaneous split screen video monitoring to record standard sleep variables as well as to evaluate movements to differentiate between tics and regular movements. Severity of Tourette's syndrome during the day was assessed with the Tourette's syndrome severity scale. RESULTS—Sleep was significantly more disturbed in patients with Tourette's syndrome than in controls, with decreased sleep efficiency and slow wave sleep percentage, increased sleep latency, percentage of stage I, percentage of awakeness, number of awakenings, and sleep stage changes and more overall movements during sleep. Severity of Tourette's syndrome during the day correlated significantly and positive with number of awakenings and sleep stage changes and negatively with sleep efficiency. In addition to an increased number of regular movements patients had tics in all sleep stages. Tic frequency as well as frequency of regular movements was significantly higher in REM than in non-REM sleep which was also the case for regular movements of the controls. No disturbance of either REM sleep percentage or REM latency was found. CONCLUSION—Despite normal total sleep time and unaltered REM sleep variables patients with Tourette's syndrome have markedly disturbed sleep. Severity of the syndrome during the day is an important predictor of sleep alteration in patients. The increased rate of tics during REM sleep parallels the overall increased movement activity of patients during REM as well as non-REM sleep. The increased motor activity may be attributable to a state of hyperarousal rather than a disturbed cholinergic system.

Sleep-wake related discharge properties of basal forebrain neurons recorded with micropipettes in head-fixed rats.

Abstract: The basal forebrain has been shown to play an important role in cortical activation of wake and paradoxical sleep (PS), yet has also been posited to play a role in slow wave sleep (SWS). In an effo...

Sleep and circadian rhythms in mammalian torpor

Abstract: Sleep and circadian rhythms are the primary determinants of arousal state, and torpor is the most extreme state change that occurs in mammals. The view that torpor is an evolutionary extension of sleep is supported by electrophysiological studies. However, comparisons of factors that influence the expression of sleep and torpor uncover significant differences. Deep sleep immediately following torpor suggests that torpor is functionally a period of sleep deprivation. Recent studies that employ post-torpor sleep deprivation, however, show that the post-torpor intense sleep is not homeostatically regulated, but might be a reflection of synaptic loss and replacement. The circadian system regulates sleep expression in euthermic mammals in such a way that would appear to preclude multiday bouts of torpor. Indeed, the circadian system is robust in animals that show shallow torpor, but its activity in hibernators is at least damped if not absent. There is good evidence from some species, however, that the circadian system plays important roles in the timing of bouts of torpor.