Sleep
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The fruit fly Drosophila melanogaster is emerging as a promising model system for the genetic dissection of sleep. As in mammals, sleep in the fruit fly is a reversible state of reduced responsiveness to the external world and has been defined using an array of behavioral, pharmacologic, molecular, and electrophysiologic criteria. A central feature of mammalian sleep is its homeostatic regulation by the amount of previous wakefulness. Dissecting the mechanisms of homeostatic regulation is likely to provide key insights into the functions of sleep. Thus, it is important to establish to what extent sleep homeostasis is similar between mammals and flies. This study was designed to determine whether in flies, as in mammals, (1) sleep rebound is dependent on prior time awake; (2) sleep deprivation affects the intensity, in addition to the duration, of sleep rebound; (3) sleep loss impairs vigilance and performance; (4) the sleep homeostatic response is conserved among different wild-type lines, and between female and male flies of the same line. ⋯ The sleep homeostatic response in fruit flies is a stable phenotype and shares most of, if not all, the major features of mammalian sleep homeostasis, thus supporting the use of Drosophila as a model system for the genetic dissection of sleep mechanisms and functions.
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To determine the frequency of classical markers of non-rapid eye movement (NREM) parasomnias--hypersynchronous delta sleep (HSD) electroencephalogram waves and sudden arousals from slow-wave sleep (SWS)--in patients without histories of somnambulism or other NREM parasomnias. ⋯ HSD and SWS arousals were a common finding in patients without clinical histories of sleepwalking or other parasomnias but who were found to have frequent respiratory-related arousals during sleep. HSD and SWS arousals thus have a low specificity for NREM parasomnias and, without further research, are not useful for the objective confirmation of parasomnias in clinical evaluations and in the forensic evaluation of sleepwalking as a legal defense.
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As the effects of general slowness and decreased attentional capacity on higher executive attention have not been fully taken into account in the sleep apnea literature, we statistically controlled for basic attentional performance in evaluating executive attention per se in sleep apnea patients. ⋯ In addition to vigilance decrements, attentional capacity deficits clearly emerge, ie, slowed information processing and decreased short-term memory span. However, no specific clinical indications for executive attentional deficits--such as disinhibition, distractibility, perseveration, attentional switching dysfunction, decreased design fluency, or an impaired central executive of working memory--are found in patients with severe sleep apnea. Their cognitive performance seems very similar to the cognitive decline found after sleep loss and qualitatively different from patients with chronic obstructive pulmonary disease, suggesting sleepiness as the primary factor in a parsimonious explanation for the attention deficits in sleep apnea, without the need to assume prefrontal brain damage.
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To compare sleep-spindle incidence (number of spindles per minute of non-rapid eye movement [NREM] stage 2 sleep) and duration, spindle wave time (seconds per epoch in NREM stage 2 sleep), spindle frequency activity, and pain measures (pressure pain threshold, number of tender points, skinfold tenderness) between midlife women with fibromyalgia (FM) and moderate to high pain to a control group of sedentary women without pain. A second goal was to explore the extent to which pain pressure thresholds, age, and depression explain the variance in spindle incidence. ⋯ Women with FM and pain have fewer sleep spindles and reduced electroencephalogram power in spindle frequency activity compared to control women of similar age. These data imply that some aspect of thalamocortical mechanisms of spindle generation might be impaired in FM.