During wakefulness, monoaminergic and cholinergic nuclei inhibit VLPO neurons, thereby reducing their own inhibition and the inhibition of hypocretin/orexin neurons and other wake-promoting regions. This model suggests that the sleep-promoting gamma-aminobutyric acid- (GABA-)ergic neurons in the ventrolateral preoptic nucleus (VLPO) and the wake-promoting monoaminergic and cholinergic nuclei orchestrate a reciprocal inhibition to enable rapid transitions between sleep and wakefulness. 4 propose a “flip-flop” model of sleep regulation as a possible mechanism for physiological sleep-wake transitions. 3 They argued that although predominantly elements of REM sleep occur in other sleep stages (e.g., muscle tone loss in cataplexy during wakefulness), “almost all conceivable dissociations of normal state boundaries of wakefulness, NREM sleep, and REM sleep have been reported”. 2 opened a discourse in 1986 whether narcolepsy is a disorder of state boundary control rather than an exclusive disorder of REM sleep. Many symptoms in narcolepsy patients indicate a specific pathological dysregulation of REM sleep and wakefulness, whereas non-rapid eye movement (NREM) sleep seems to be less affected. 1 Most of these symptoms may appear in a broad range of sleep disorders, but cataplexy is pathognomonic for narcolepsy type 1. Patients with narcolepsy type 1 experience excessive daytime sleepiness, cataplexy (sudden loss of muscle tone upon strong emotions), fragmented nighttime sleep, and abnormal expressions of rapid eye movement (REM) sleep, such as rapid transitions into REM sleep, hypnagogic and hypnopompic hallucinations, and sleep paralysis. From a clinical perspective, this study also provides proof-of-principle that analysis of EEG dynamics may add to the diagnostic evaluation in sleep in patients with suspected narcolepsy. Our findings highlight the value of quantitative analyses of EEG in healthy and pathological sleep to gain greater understanding of the underlying mechanisms of dysfunctional sleep regulation.
This approach allows for the analysis of dynamic aspects of sleep, which are not accessible by conventional sleep analysis. We applied a model-based approach to analyze sleep electroencephalography (EEG) in patients with narcolepsy type 1 and control subjects.
0 kommentar(er)
