The Drosophila core circadian circuit contains distinct groups of interacting neurons that give rise to diurnal sleep-wake patterns. Previous work showed that a subset of dorsal neurons 1 (DN1s) are sleep-promoting through their inhibition of activity-promoting circadian pacemakers. Here we show that these anterior-projecting DNs (APDNs) also "exit" the circadian circuitry and communicate with the homeostatic sleep center in higher brain regions to regulate sleep and sleep-wake arousal. These APDNs connect to a small, discrete subset of tubercular-bulbar neurons, which are connected in turn to specific sleep-centric ellipsoid body (EB)-ring neurons of the central complex. Remarkably, activation of the APDNs produces sleep-like oscillations in the EB and affects arousal. The data indicate that this APDN-TuBu-EB circuit temporally regulates sleep-wake arousal in addition to the previously defined role of the TuBu-EB circuit in vision, navigation, and attention.
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http://dx.doi.org/10.1016/j.neuron.2018.09.002 | DOI Listing |
Clocks Sleep
January 2025
Circadian Physics Group, School of Physics, University of Sydney, Sydney, NSW 2006, Australia.
Fixed sleep schedules with an 8 h time in bed (TIB) are used to ensure participants are well-rested before laboratory studies. However, such schedules may lead to cumulative excess wakefulness in young individuals. Effects on older individuals are unknown.
View Article and Find Full Text PDFNat Sci Sleep
January 2025
Department of Insect Genetics, Institute of Cytology and Genetics of the Siberian Branch, the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
Purpose: Two previously proposed modelling approaches to explain the bimodal pattern of activity and/or sleep in are based on 1) the concept of morning and evening oscillators underlying the peaks of activity in the morning and evening, respectively, and 2) the concept of two cycles of buildup and decay of sleep pressure, gated only by the circadian oscillator. Previously, we simulated 24-h alertness-sleepiness curves in humans using a model postulating the circadian modulation of the buildup and decay phases of two (wake and sleep) homeostatic processes. Here, we tested whether a similar model could be applied to simulate the bimodal 24-h rhythm of fly locomotor activity and sleep.
View Article and Find Full Text PDFPeerJ
January 2025
Department of Graduate, Nanjing Sport Institute, Nanjing, Jiangsu, China.
Objective: Sleep is the most efficient means of recovery for athletes, guaranteeing optimal athletic performance. However, many athletes frequently experience sleep problems. Our study aims to describe the sleep-wake patterns of fencing athletes and determine whether factors, such as sex, competitive level and training schedules, could affect the sleep-wake rhythm.
View Article and Find Full Text PDFUnlabelled: The locus coeruleus (LC) is the primary source of noradrenaline (NA) in brain and its activity is essential for learning, memory, stress, arousal, and mood. LC-NA neuron activity varies over the sleep-wake cycle, with higher activity during wakefulness, correlating with increased CSF NA levels. Whether spontaneous and burst firing of LC-NA neurons during active and inactive periods is controlled by mechanisms independent of wakefulness and natural sleep, is currently unknown.
View Article and Find Full Text PDFJ Physiol Sci
January 2025
Department of Neuroscience, School of Science and Advanced Technologies in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by progressive cognitive decline and memory loss. Sleep-wake disorders are an extremely predominant and often disabling aspect of AD. Ox is vital in maintaining the sleep-wake cycle and promoting wakefulness.
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