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Mutti C, Misirocchi F, Zilioli A, Rausa F, Pizzarotti S, Spallazzi M, Parrino L. Sleep and brain evolution across the human lifespan: A mutual embrace. FRONTIERS IN NETWORK PHYSIOLOGY 2022; 2:938012. [PMID: 36926070 PMCID: PMC10013002 DOI: 10.3389/fnetp.2022.938012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 07/08/2022] [Indexed: 11/13/2022]
Abstract
Sleep can be considered a window to ascertain brain wellness: it dynamically changes with brain maturation and can even indicate the occurrence of concealed pathological processes. Starting from prenatal life, brain and sleep undergo an impressive developmental journey that accompanies human life throughout all its steps. A complex mutual influence rules this fascinating course and cannot be ignored while analysing its evolution. Basic knowledge on the significance and evolution of brain and sleep ontogenesis can improve the clinical understanding of patient's wellbeing in a more holistic perspective. In this review we summarized the main notions on the intermingled relationship between sleep and brain evolutionary processes across human lifespan, with a focus on sleep microstructure dynamics.
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Affiliation(s)
- Carlotta Mutti
- Department of General and Specialized Medicine, Parma University Hospital, Parma, Italy
| | - Francesco Misirocchi
- Department of General and Specialized Medicine, Parma University Hospital, Parma, Italy
| | - Alessandro Zilioli
- Department of General and Specialized Medicine, Parma University Hospital, Parma, Italy
| | - Francesco Rausa
- Department of General and Specialized Medicine, Parma University Hospital, Parma, Italy
| | - Silvia Pizzarotti
- Department of General and Specialized Medicine, Parma University Hospital, Parma, Italy
| | - Marco Spallazzi
- Department of General and Specialized Medicine, Parma University Hospital, Parma, Italy
| | - Liborio Parrino
- Department of General and Specialized Medicine, Parma University Hospital, Parma, Italy
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52
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Zhuo J, Gill JP, Jansen ED, Jenkins MW, Chiel HJ. Use of an invertebrate animal model ( Aplysia californica) to develop novel neural interfaces for neuromodulation. Front Neurosci 2022; 16:1080027. [PMID: 36620467 PMCID: PMC9813496 DOI: 10.3389/fnins.2022.1080027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022] Open
Abstract
New tools for monitoring and manipulating neural activity have been developed with steadily improving functionality, specificity, and reliability, which are critical both for mapping neural circuits and treating neurological diseases. This review focuses on the use of an invertebrate animal, the marine mollusk Aplysia californica, in the development of novel neurotechniques. We review the basic physiological properties of Aplysia neurons and discuss the specific aspects that make it advantageous for developing novel neural interfaces: First, Aplysia nerves consist only of unmyelinated axons with various diameters, providing a particularly useful model of the unmyelinated C fibers in vertebrates that are known to carry important sensory information, including those that signal pain. Second, Aplysia's neural tissues can last for a long period in an ex vivo experimental setup. This allows comprehensive tests such as the exploration of parameter space on the same nerve to avoid variability between animals and minimize animal use. Third, nerves in large Aplysia can be many centimeters in length, making it possible to easily discriminate axons with different diameters based on their conduction velocities. Aplysia nerves are a particularly good approximation of the unmyelinated C fibers, which are hard to stimulate, record, and differentiate from other nerve fibers in vertebrate animal models using epineural electrodes. Fourth, neurons in Aplysia are large, uniquely identifiable, and electrically compact. For decades, researchers have used Aplysia for the development of many novel neurotechnologies. Examples include high-frequency alternating current (HFAC), focused ultrasound (FUS), optical neural stimulation, recording, and inhibition, microelectrode arrays, diamond electrodes, carbon fiber microelectrodes, microscopic magnetic stimulation and magnetic resonance electrical impedance tomography (MREIT). We also review a specific example that illustrates the power of Aplysia for accelerating technology development: selective infrared neural inhibition of small-diameter unmyelinated axons, which may lead to a translationally useful treatment in the future. Generally, Aplysia is suitable for testing modalities whose mechanism involves basic biophysics that is likely to be similar across species. As a tractable experimental system, Aplysia californica can help the rapid development of novel neuromodulation technologies.
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Affiliation(s)
- Junqi Zhuo
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Jeffrey P Gill
- Department of Biology, Case Western Reserve University, Cleveland, OH, United States
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States.,Biophotonics Center, Vanderbilt University, Nashville, TN, United States.,Department of Neurological Surgery, Vanderbilt University, Nashville, TN, United States
| | - Michael W Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States.,Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - Hillel J Chiel
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States.,Department of Biology, Case Western Reserve University, Cleveland, OH, United States.,Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
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53
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Zada D, Sela Y, Matosevich N, Monsonego A, Lerer-Goldshtein T, Nir Y, Appelbaum L. Parp1 promotes sleep, which enhances DNA repair in neurons. Mol Cell 2021; 81:4979-4993.e7. [PMID: 34798058 PMCID: PMC8688325 DOI: 10.1016/j.molcel.2021.10.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 10/18/2021] [Accepted: 10/26/2021] [Indexed: 10/19/2022]
Abstract
The characteristics of the sleep drivers and the mechanisms through which sleep relieves the cellular homeostatic pressure are unclear. In flies, zebrafish, mice, and humans, DNA damage levels increase during wakefulness and decrease during sleep. Here, we show that 6 h of consolidated sleep is sufficient to reduce DNA damage in the zebrafish dorsal pallium. Induction of DNA damage by neuronal activity and mutagens triggered sleep and DNA repair. The activity of the DNA damage response (DDR) proteins Rad52 and Ku80 increased during sleep, and chromosome dynamics enhanced Rad52 activity. The activity of the DDR initiator poly(ADP-ribose) polymerase 1 (Parp1) increased following sleep deprivation. In both larva zebrafish and adult mice, Parp1 promoted sleep. Inhibition of Parp1 activity reduced sleep-dependent chromosome dynamics and repair. These results demonstrate that DNA damage is a homeostatic driver for sleep, and Parp1 pathways can sense this cellular pressure and facilitate sleep and repair activity.
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Affiliation(s)
- David Zada
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yaniv Sela
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv-Yafo 69978, Israel
| | - Noa Matosevich
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv-Yafo 69978, Israel
| | - Adir Monsonego
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Tali Lerer-Goldshtein
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yuval Nir
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv-Yafo 69978, Israel
| | - Lior Appelbaum
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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54
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Jaggard JB, Wang GX, Mourrain P. Non-REM and REM/paradoxical sleep dynamics across phylogeny. Curr Opin Neurobiol 2021; 71:44-51. [PMID: 34583217 PMCID: PMC8719594 DOI: 10.1016/j.conb.2021.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 12/14/2022]
Abstract
All animals carefully studied sleep, suggesting that sleep as a behavioral state exists in all animal life. Such evolutionary maintenance of an otherwise vulnerable period of environmental detachment suggests that sleep must be integral in fundamental biological needs. Despite over a century of research, the knowledge of what sleep does at the tissue, cellular or molecular levels remain cursory. Currently, sleep is defined based on behavioral criteria and physiological measures rather than at the cellular or molecular level. Physiologically, sleep has been described as two main states, non-rapid eye moment (NREM) and REM/paradoxical sleep (PS), which are defined in the neocortex by synchronous oscillations and paradoxical wake-like activity, respectively. For decades, these two sleep states were believed to be defining characteristics of only mammalian and avian sleep. Recent work has revealed slow oscillation, silencing, and paradoxical/REM-like activities in reptiles, fish, flies, worms, and cephalopods suggesting that these sleep dynamics and associated physiological states may have emerged early in animal evolution. Here, we discuss these recent developments supporting the conservation of neural dynamics (silencing, oscillation, paradoxical activity) of sleep states across phylogeny.
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Affiliation(s)
- James B Jaggard
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Gordon X Wang
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA; Wu Tsai Neuroscience Institute, Stanford University, Stanford, CA, USA
| | - Philippe Mourrain
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA; INSERM 1024, Ecole Normale Supérieure, Paris, France.
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55
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Huang H, Possidente DR, Vecsey CG. Optogenetic activation of SIFamide (SIFa) neurons induces a complex sleep-promoting effect in the fruit fly Drosophila melanogaster. Physiol Behav 2021; 239:113507. [PMID: 34175361 DOI: 10.1016/j.physbeh.2021.113507] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/20/2021] [Accepted: 06/22/2021] [Indexed: 10/21/2022]
Abstract
Sleep is a universal and extremely complicated function. Sleep is regulated by two systems-sleep homeostasis and circadian rhythms. In a wide range of species, neuropeptides have been found to play a crucial role in the communication and synchronization between different components of both systems. In the fruit fly Drosophila melanogaster, SIFamide (SIFa) is a neuropeptide that has been reported to be expressed in 4 neurons in the pars intercerebralis (PI) area of the brain. Previous work has shown that transgenic ablation of SIFa neurons, mutation of SIFa itself, or knockdown of SIFa receptors reduces sleep, suggesting that SIFa is sleep-promoting. However, those were all constitutive manipulations that could have affected development or resulted in compensation, so the role of SIFa signaling in sleep regulation during adulthood remains unclear. In the current study, we examined the sleep-promoting effect of SIFa through an optogenetic approach, which allowed for neuronal activation with high temporal resolution, while leaving development unaffected. We found that activation of the red-light sensor Chrimson in SIFa neurons promoted sleep in flies in a sexually dimorphic manner, where the magnitude of the sleep effect was greater in females than in males. Because neuropeptidergic neurons often also release other transmitters, we used RNA interference to knock down SIFa while also optogenetically activating SIFa neurons. SIFa knockdown only partially reduced the magnitude of the sleep effect, suggesting that release of other transmitters may contribute to the sleep induction when SIFa neurons are activated. Video-based analysis showed that activation of SIFa neurons for as brief a period as 1 second was able to decrease walking behavior for minutes after the stimulus. Future studies should aim to identify the transmitters that are utilized by SIFa neurons and characterize their upstream activators and downstream targets. It would also be of interest to determine how acute optogenetic activation of SIFa neurons alters other behaviors that have been linked to SIFa, such as mating and feeding.
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Affiliation(s)
- Haoyang Huang
- Neuroscience Program, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866
| | - Debra R Possidente
- Neuroscience Program, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866
| | - Christopher G Vecsey
- Neuroscience Program, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866.
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56
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Flies sense the world while sleeping. Nature 2021; 598:423-424. [PMID: 34588643 DOI: 10.1038/d41586-021-02441-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Smidt SDE, Hitt T, Zemel BS, Mitchell JA. Sex differences in childhood sleep and health implications. Ann Hum Biol 2021; 48:474-484. [PMID: 35105205 PMCID: PMC9254351 DOI: 10.1080/03014460.2021.1998624] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 06/16/2021] [Accepted: 06/28/2021] [Indexed: 10/19/2022]
Abstract
CONTEXT Sleep is critical for optimal childhood metabolic health and neurodevelopment. However, there is limited knowledge regarding childhood sex differences in sleep, including children with neurodevelopmental disorders, and the impact of such differences on metabolic health. OBJECTIVE To evaluate if sex differences in childhood sleep exist and if sleep associates with metabolic health outcomes equally by sex. Using autism spectrum disorder (ASD) as a case study, we also examine sleep sex differences in children with a neurodevelopmental disorder. METHODS A narrative review explored the literature focussing on sex differences in childhood sleep. RESULTS Sex differences in sleep were not detected among pre-adolescents. However, female adolescents were more likely to report impaired sleep than males. Childhood obesity is more common in males. Shorter sleep duration may be associated with obesity in male pre-adolescents/adolescents; although findings are mixed. ASD is male-predominant; yet, there was an indication that pre-adolescent female children with ASD had more impaired sleep. CONCLUSION Sex differences in sleep appear to emerge in adolescence with more impaired sleep in females. This trend was also observed among pre-adolescent female children with ASD. Further research is needed on sex differences in childhood sleep and metabolic health and the underlying mechanisms driving these differences.
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Affiliation(s)
- Stacey D. Elkhatib Smidt
- Division of Neurology, Children’s Hospital of Philadelphia, PA
- Sleep Center, Children’s Hospital of Philadelphia, PA
- Division of Sleep Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Talia Hitt
- Division of Endocrinology and Diabetes, Children’s Hospital of Philadelphia, PA
| | - Babette S. Zemel
- Division of Gastroenterology, Hepatology, and Nutrition, Children’s Hospital of Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Jonathan A. Mitchell
- Division of Gastroenterology, Hepatology, and Nutrition, Children’s Hospital of Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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58
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O'Gorman M, Thakur S, Imrie G, Moran RL, Choy S, Sifuentes-Romero I, Bilandžija H, Renner KJ, Duboué E, Rohner N, McGaugh SE, Keene AC, Kowalko JE. Pleiotropic function of the oca2 gene underlies the evolution of sleep loss and albinism in cavefish. Curr Biol 2021; 31:3694-3701.e4. [PMID: 34293332 DOI: 10.1016/j.cub.2021.06.077] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 03/22/2021] [Accepted: 06/25/2021] [Indexed: 12/29/2022]
Abstract
Adaptation to novel environments often involves the evolution of multiple morphological, physiological, and behavioral traits. One striking example of multi-trait evolution is the suite of traits that has evolved repeatedly in cave animals, including regression of eyes, loss of pigmentation, and enhancement of non-visual sensory systems.1,2 The Mexican tetra, Astyanax mexicanus, consists of fish that inhabit at least 30 caves in Mexico and ancestral-like surface fish that inhabit the rivers of Mexico and southern Texas.3 Cave A. mexicanus are interfertile with surface fish and have evolved a number of traits, including reduced pigmentation, eye loss, and alterations to behavior.4-6 To define relationships between different cave-evolved traits, we phenotyped 208 surface-cave F2 hybrid fish for numerous morphological and behavioral traits. We found differences in sleep between pigmented and albino hybrid fish, raising the possibility that these traits share a genetic basis. In cavefish and other species, mutations in oculocutaneous albinism 2 (oca2) cause albinism.7-12 Surface fish with mutations in oca2 displayed both albinism and reduced sleep. Further, this mutation in oca2 fails to complement sleep loss when surface fish harboring this engineered mutation are crossed to independently evolved populations of albino cavefish with naturally occurring mutations in oca2. Analysis of the oca2 locus in wild-caught cave and surface fish suggests that oca2 is under positive selection in 3 cave populations. Taken together, these findings identify oca2 as a novel regulator of sleep and suggest that a pleiotropic function of oca2 underlies the adaptive evolution of albinism and sleep loss.
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Affiliation(s)
- Morgan O'Gorman
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Sunishka Thakur
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Gillian Imrie
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Rachel L Moran
- Department of Ecology, Evolution, and Behavior. University of Minnesota, St. Paul, MN 55108, USA
| | - Stefan Choy
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA
| | | | - Helena Bilandžija
- Department of Molecular Biology, Rudjer Boskovic Institute, 10000 Zagreb, Croatia
| | - Kenneth J Renner
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - Erik Duboué
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA; Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | | | - Suzanne E McGaugh
- Department of Ecology, Evolution, and Behavior. University of Minnesota, St. Paul, MN 55108, USA
| | - Alex C Keene
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA; Department of Biology Science, Florida Atlantic University, Jupiter, FL 33458, USA.
| | - Johanna E Kowalko
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter, FL 33458, USA; Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA.
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Giri A, Srinivasan A, Sundar IK. COVID-19: Sleep, Circadian Rhythms and Immunity - Repurposing Drugs and Chronotherapeutics for SARS-CoV-2. Front Neurosci 2021; 15:674204. [PMID: 34220430 PMCID: PMC8249936 DOI: 10.3389/fnins.2021.674204] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 05/05/2021] [Indexed: 01/08/2023] Open
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has affected nearly 28 million people in the United States and has caused more than five hundred thousand deaths as of February 21, 2021. As the novel coronavirus continues to take its toll in the United States and all across the globe, particularly among the elderly (>65 years), clinicians and translational researchers are taking a closer look at the nexus of sleep, circadian rhythms and immunity that may contribute toward a more severe coronavirus disease-19 (COVID-19). SARS-CoV-2-induced multi-organ failure affects both central and peripheral organs, causing increased mortality in the elderly. However, whether differences in sleep, circadian rhythms, and immunity between older and younger individuals contribute to the age-related differences in systemic dysregulation of target organs observed in SARS-CoV-2 infection remain largely unknown. Current literature demonstrates the emerging role of sleep, circadian rhythms, and immunity in the development of chronic pulmonary diseases and respiratory infections in human and mouse models. The exact mechanism underlying acute respiratory distress syndrome (ARDS) and other cardiopulmonary complications in elderly patients in combination with associated comorbidities remain unclear. Nevertheless, understanding the critical role of sleep, circadian clock dysfunction in target organs, and immune status of patients with SARS-CoV-2 may provide novel insights into possible therapies. Chronotherapy is an emerging concept that is gaining attention in sleep medicine. Accumulating evidence suggests that nearly half of all physiological functions follow a strict daily rhythm. However, healthcare professionals rarely take implementing timed-administration of drugs into consideration. In this review, we summarize recent findings directly relating to the contributing roles of sleep, circadian rhythms and immune response in modulating infectious disease processes, and integrate chronotherapy in the discussion of the potential drugs that can be repurposed to improve the treatment and management of COVID-19.
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Affiliation(s)
| | | | - Isaac Kirubakaran Sundar
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS, United States
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Lloyd E, Chhouk B, Conith AJ, Keene AC, Albertson RC. Diversity in rest-activity patterns among Lake Malawi cichlid fishes suggests a novel axis of habitat partitioning. J Exp Biol 2021; 224:238727. [PMID: 33658242 PMCID: PMC8077532 DOI: 10.1242/jeb.242186] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/11/2021] [Indexed: 12/04/2022]
Abstract
Animals display remarkable diversity in rest and activity patterns that are regulated by endogenous foraging strategies, social behaviors and predator avoidance. Alteration in the circadian timing of activity or the duration of rest–wake cycles provide a central mechanism for animals to exploit novel niches. The diversity of the >3000 cichlid species throughout the world provides a unique opportunity to examine variation in locomotor activity and rest. Lake Malawi alone is home to over 500 species of cichlids that display divergent behaviors and inhabit well-defined niches throughout the lake. These species are presumed to be diurnal, though this has never been tested systematically. Here, we measured locomotor activity across the circadian cycle in 11 Lake Malawi cichlid species. We documented surprising variability in the circadian time of locomotor activity and the duration of rest. In particular, we identified a single species, Tropheops sp. ‘red cheek’, that is nocturnal. Nocturnal behavior was maintained when fish were provided shelter, but not under constant darkness, suggesting that it results from acute response to light rather than an endogenous circadian rhythm. Finally, we showed that nocturnality is associated with increased eye size after correcting for evolutionary history, suggesting a link between visual processing and nighttime activity. Together, these findings identify diversity of locomotor behavior in Lake Malawi cichlids and provide a system for investigating the molecular and neural basis underlying variation in nocturnal activity. Summary: Cichlids show a remarkable diversity in morphology and behavior. Cichlid species exhibit differences in strength and polarity of activity rhythms, revealing a new axis of habitat partitioning.
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Affiliation(s)
- Evan Lloyd
- Department of Biological Science, Florida Atlantic University, Jupiter, FL 33401, USA
| | - Brian Chhouk
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Andrew J Conith
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Alex C Keene
- Department of Biological Science, Florida Atlantic University, Jupiter, FL 33401, USA
| | - R Craig Albertson
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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61
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Özcürümez M, Arzideh F, Torge A, Figge A, Haeckel R, Streichert T. The influence of sampling time on indirect reference limits, decision limits, and the estimation of biological variation of random plasma glucose concentrations. J LAB MED 2021. [DOI: 10.1515/labmed-2020-0146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Objectives
Plasma glucose concentrations exhibit a pronounced daytime-dependent variation. The oscillations responsible for this are currently not considered in the determination of reference limits (RL) and decision limits.
Methods
We characterized the daily variation inherent in large-scale laboratory data from two different university hospitals (site 1 n=513,682, site 2 n=204,001). Continuous and distinct RL for daytime and night were estimated. Diurnal characteristics of glucose concentrations were further investigated by quantile regression analyses introducing age and cosinor-functions as predictors in the model.
Results
Diurnal variations expressed as amplitude/Midline Estimating Statistic of Rhythm (MESOR) ratio, averaged 7.7% (range 5.9–9.3%). The amplitude of glucose levels decreased with increasing concentrations. Between 06:00 and 10:00 h an average decrease of 4% has to be considered. Nocturnal glucose samples accounted for only 5% of the total amount but contributed to 19.5% of all findings over 11.1 mmol/L. Partitioning of RL between day and night is merely justified for the upper reference limit. The nocturnal upper RLs for both genders differed from those obtained during the day by 11.0 and 10.6% at site 1 and by 7.6 and 7.5% at site 2.
Conclusions
We conclude that indirect approaches to estimate upper RL of random plasma glucose concentrations require stratification concerning the time of sample collection.
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Affiliation(s)
- Mustafa Özcürümez
- Medizinische Klinik, Universitätsklinikum Knappschaftskrankenhaus Bochum , Bochum , Germany
| | - Farhad Arzideh
- Medizinische Klinik, Universitätsklinikum Knappschaftskrankenhaus Bochum , Bochum , Germany
| | - Antje Torge
- Institut für Klinische Chemie , Universitätsklinikum Schleswig-Holstein , Kiel , Germany
| | - Anja Figge
- Medizinische Klinik, Universitätsklinikum Knappschaftskrankenhaus Bochum , Bochum , Germany
| | - Rainer Haeckel
- Bremer Zentrum für Laboratoriumsmedizin, Klinikum Bremen Mitte , Bremen , Germany
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Silva V, Palacios-Muñoz A, Okray Z, Adair KL, Waddell S, Douglas AE, Ewer J. The impact of the gut microbiome on memory and sleep in Drosophila. J Exp Biol 2021; 224:jeb233619. [PMID: 33376141 PMCID: PMC7875489 DOI: 10.1242/jeb.233619] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/21/2020] [Indexed: 12/17/2022]
Abstract
The gut microbiome has been proposed to influence diverse behavioral traits of animals, although the experimental evidence is limited and often contradictory. Here, we made use of the tractability of Drosophila melanogaster for both behavioral analyses and microbiome studies to test how elimination of microorganisms affects a number of behavioral traits. Relative to conventional flies (i.e. with unaltered microbiome), microbiologically sterile (axenic) flies displayed a moderate reduction in memory performance in olfactory appetitive conditioning and courtship assays. The microbiological status of the flies had a small or no effect on anxiety-like behavior (centrophobism) or circadian rhythmicity of locomotor activity, but axenic flies tended to sleep for longer and displayed reduced sleep rebound after sleep deprivation. These last two effects were robust for most tests conducted on both wild-type Canton S and w1118 strains, as well for tests using an isogenized panel of flies with mutations in the period gene, which causes altered circadian rhythmicity. Interestingly, the effect of absence of microbiota on a few behavioral features, most notably instantaneous locomotor activity speed, varied among wild-type strains. Taken together, our findings demonstrate that the microbiome can have subtle but significant effects on specific aspects of Drosophila behavior, some of which are dependent on genetic background.
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Affiliation(s)
- Valeria Silva
- Instituto de Neurociencias, and Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Angelina Palacios-Muñoz
- Instituto de Neurociencias, and Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Centro de Investigación Interoperativo en Ciencias Odontológicas y Médicas, Facultad de Odontología, Universidad de Valparaíso, Valparaíso 2360004, Chile
| | - Zeynep Okray
- Centre for Neural Circuits & Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Karen L Adair
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA
| | - Scott Waddell
- Centre for Neural Circuits & Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Angela E Douglas
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
| | - John Ewer
- Instituto de Neurociencias, and Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso 2360102, Chile
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Tainton-Heap LAL, Kirszenblat LC, Notaras ET, Grabowska MJ, Jeans R, Feng K, Shaw PJ, van Swinderen B. A Paradoxical Kind of Sleep in Drosophila melanogaster. Curr Biol 2020; 31:578-590.e6. [PMID: 33238155 DOI: 10.1016/j.cub.2020.10.081] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 09/14/2020] [Accepted: 10/27/2020] [Indexed: 01/01/2023]
Abstract
The dynamic nature of sleep in many animals suggests distinct stages that serve different functions. Genetic sleep induction methods in animal models provide a powerful way to disambiguate these stages and functions, although behavioral methods alone are insufficient to accurately identify what kind of sleep is being engaged. In Drosophila, activation of the dorsal fan-shaped body (dFB) promotes sleep, but it remains unclear what kind of sleep this is, how the rest of the fly brain is behaving, or if any specific sleep functions are being achieved. Here, we developed a method to record calcium activity from thousands of neurons across a volume of the fly brain during spontaneous sleep and compared this to dFB-induced sleep. We found that spontaneous sleep typically transitions from an active "wake-like" stage to a less active stage. In contrast, optogenetic activation of the dFB promotes sustained wake-like levels of neural activity even though flies become unresponsive to mechanical stimuli. When we probed flies with salient visual stimuli, we found that the activity of visually responsive neurons in the central brain was blocked by transient dFB activation, confirming an acute disconnect from the external environment. Prolonged optogenetic dFB activation nevertheless achieved a key sleep function by correcting visual attention defects brought on by sleep deprivation. These results suggest that dFB activation promotes a distinct form of sleep in Drosophila, where brain activity appears similar to wakefulness, but responsiveness to external sensory stimuli is profoundly suppressed.
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Affiliation(s)
- Lucy A L Tainton-Heap
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Leonie C Kirszenblat
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia; RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Eleni T Notaras
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Martyna J Grabowska
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Rhiannon Jeans
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Kai Feng
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul J Shaw
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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64
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Hu Y, Korovaichuk A, Astiz M, Schroeder H, Islam R, Barrenetxea J, Fischer A, Oster H, Bringmann H. Functional Divergence of Mammalian TFAP2a and TFAP2b Transcription Factors for Bidirectional Sleep Control. Genetics 2020; 216:735-752. [PMID: 32769099 PMCID: PMC7648577 DOI: 10.1534/genetics.120.303533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/20/2020] [Indexed: 11/18/2022] Open
Abstract
Sleep is a conserved behavioral state. Invertebrates typically show quiet sleep, whereas in mammals, sleep consists of periods of nonrapid-eye-movement sleep (NREMS) and REM sleep (REMS). We previously found that the transcription factor AP-2 promotes sleep in Caenorhabditiselegans and Drosophila In mammals, several paralogous AP-2 transcription factors exist. Sleep-controlling genes are often conserved. However, little is known about how sleep genes evolved from controlling simpler types of sleep to govern complex mammalian sleep. Here, we studied the roles of Tfap2a and Tfap2b in sleep control in mice. Consistent with our results from C. elegans and Drosophila, the AP-2 transcription factors Tfap2a and Tfap2b also control sleep in mice. Surprisingly, however, the two AP-2 paralogs play contrary roles in sleep control. Tfap2a reduction of function causes stronger delta and theta power in both baseline and homeostasis analysis, thus indicating increased sleep quality, but did not affect sleep quantity. By contrast, Tfap2b reduction of function decreased NREM sleep time specifically during the dark phase, reduced NREMS and REMS power, and caused a weaker response to sleep deprivation. Consistent with the observed signatures of decreased sleep quality, stress resistance and memory were impaired in Tfap2b mutant animals. Also, the circadian period was slightly shortened. Taken together, AP-2 transcription factors control sleep behavior also in mice, but the role of the AP-2 genes functionally diversified to allow for a bidirectional control of sleep quality. Divergence of AP-2 transcription factors might perhaps have supported the evolution of more complex types of sleep.
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Affiliation(s)
- Yang Hu
- Max Planck Research Group "Sleep and Waking", Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
| | - Alejandra Korovaichuk
- Max Planck Research Group "Sleep and Waking", Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
| | - Mariana Astiz
- Institute of Neurobiology, University of Lübeck, 23562, Germany
| | - Henning Schroeder
- German Center for Neurodegenerative Diseases, Göttingen 37075, Germany
| | - Rezaul Islam
- German Center for Neurodegenerative Diseases, Göttingen 37075, Germany
| | - Jon Barrenetxea
- Max Planck Research Group "Sleep and Waking", Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
| | - Andre Fischer
- German Center for Neurodegenerative Diseases, Göttingen 37075, Germany
- Department for Psychiatry and Psychotherapy, University Medical Center, Göttingen 37075, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37073, Germany
| | - Henrik Oster
- Institute of Neurobiology, University of Lübeck, 23562, Germany
| | - Henrik Bringmann
- Max Planck Research Group "Sleep and Waking", Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
- Department of Animal Physiology/Neurophysiology, Philipps University Marburg, Marburg 35043, Germany
- BIOTEC of the Technical University Dresden, Dresden 01307, Germany
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65
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Ajayi OM, Eilerts DF, Bailey ST, Vinauger C, Benoit JB. Do Mosquitoes Sleep? Trends Parasitol 2020; 36:888-897. [PMID: 32952061 PMCID: PMC8094063 DOI: 10.1016/j.pt.2020.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 10/23/2022]
Abstract
Sleep is a phenomenon conserved across the animal kingdom, where studies on Drosophila melanogaster have revealed that sleep phenotypes and molecular underpinnings are similar to those in mammals. However, little is known about sleep in blood-feeding arthropods, which have a critical role in public health as disease vectors. Specifically, sleep studies in mosquitoes are lacking despite considerable focus on how circadian processes, which have a central role in regulating sleep/wake cycles, impact activity, feeding, and immunity. Here, we review observations which suggest that sleep-like states likely occur in mosquitoes and discuss the potential role of sleep in relation to mosquito biology and their ability to function as disease vectors.
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Affiliation(s)
- Oluwaseun M Ajayi
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA. @mail.uc.edu
| | - Diane F Eilerts
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Samuel T Bailey
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Clément Vinauger
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA. @uc.edu
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66
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Sarikaya DP, Cridland J, Tarakji A, Sheehy H, Davis S, Kochummen A, Hatmaker R, Khan N, Chiu J, Begun DJ. Phenotypic coupling of sleep and starvation resistance evolves in D. melanogaster. BMC Evol Biol 2020; 20:126. [PMID: 32962630 PMCID: PMC7507639 DOI: 10.1186/s12862-020-01691-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/13/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND One hypothesis for the function of sleep is that it serves as a mechanism to conserve energy. Recent studies have suggested that increased sleep can be an adaptive mechanism to improve survival under food deprivation in Drosophila melanogaster. To test the generality of this hypothesis, we compared sleep and its plastic response to starvation in a temperate and tropical population of Drosophila melanogaster. RESULTS We found that flies from the temperate population were more starvation resistant, and hypothesized that they would engage in behaviors that are considered to conserve energy, including increased sleep and reduced movement. Surprisingly, temperate flies slept less and moved more when they were awake compared to tropical flies, both under fed and starved conditions, therefore sleep did not correlate with population-level differences in starvation resistance. In contrast, total sleep and percent change in sleep when starved were strongly positively correlated with starvation resistance within the tropical population, but not within the temperate population. Thus, we observe unexpectedly complex relationships between starvation and sleep that vary both within and across populations. These observations falsify the simple hypothesis of a straightforward relationship between sleep and energy conservation. We also tested the hypothesis that starvation is correlated with metabolic phenotypes by investigating stored lipid and carbohydrate levels, and found that stored metabolites partially contributed towards variation starvation resistance. CONCLUSIONS Our findings demonstrate that the function of sleep under starvation can rapidly evolve on short timescales and raise new questions about the physiological correlates of sleep and the extent to which variation in sleep is shaped by natural selection.
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Affiliation(s)
- Didem P Sarikaya
- Department of Evolution and Ecology, University of California Davis, Davis, California, USA.
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, USA.
| | - Julie Cridland
- Department of Evolution and Ecology, University of California Davis, Davis, California, USA
| | - Adam Tarakji
- Department of Evolution and Ecology, University of California Davis, Davis, California, USA
| | - Hayley Sheehy
- Department of Evolution and Ecology, University of California Davis, Davis, California, USA
| | - Sophia Davis
- Department of Evolution and Ecology, University of California Davis, Davis, California, USA
| | - Ashley Kochummen
- Department of Evolution and Ecology, University of California Davis, Davis, California, USA
| | - Ryan Hatmaker
- Department of Evolution and Ecology, University of California Davis, Davis, California, USA
| | - Nossin Khan
- Department of Evolution and Ecology, University of California Davis, Davis, California, USA
| | - Joanna Chiu
- Department of Nematology and Entomology, University of California Davis, Davis, California, USA
| | - David J Begun
- Department of Evolution and Ecology, University of California Davis, Davis, California, USA
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67
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Ertekin D, Kirszenblat L, Faville R, van Swinderen B. Down-regulation of a cytokine secreted from peripheral fat bodies improves visual attention while reducing sleep in Drosophila. PLoS Biol 2020; 18:e3000548. [PMID: 32745077 PMCID: PMC7426065 DOI: 10.1371/journal.pbio.3000548] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 08/13/2020] [Accepted: 07/13/2020] [Indexed: 11/29/2022] Open
Abstract
Sleep is vital for survival. Yet under environmentally challenging conditions, such as starvation, animals suppress their need for sleep. Interestingly, starvation-induced sleep loss does not evoke a subsequent sleep rebound. Little is known about how starvation-induced sleep deprivation differs from other types of sleep loss, or why some sleep functions become dispensable during starvation. Here, we demonstrate that down-regulation of the secreted cytokine unpaired 2 (upd2) in Drosophila flies may mimic a starved-like state. We used a genetic knockdown strategy to investigate the consequences of upd2 on visual attention and sleep in otherwise well-fed flies, thereby sidestepping the negative side effects of undernourishment. We find that knockdown of upd2 in the fat body (FB) is sufficient to suppress sleep and promote feeding-related behaviors while also improving selective visual attention. Furthermore, we show that this peripheral signal is integrated in the fly brain via insulin-expressing cells. Together, these findings identify a role for peripheral tissue-to-brain interactions in the simultaneous regulation of sleep quality and attention, to potentially promote adaptive behaviors necessary for survival in hungry animals.
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Affiliation(s)
- Deniz Ertekin
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Leonie Kirszenblat
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Richard Faville
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
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68
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Dissel S. Drosophila as a Model to Study the Relationship Between Sleep, Plasticity, and Memory. Front Physiol 2020; 11:533. [PMID: 32547415 PMCID: PMC7270326 DOI: 10.3389/fphys.2020.00533] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 04/30/2020] [Indexed: 12/28/2022] Open
Abstract
Humans spend nearly a third of their life sleeping, yet, despite decades of research the function of sleep still remains a mystery. Sleep has been linked with various biological systems and functions, including metabolism, immunity, the cardiovascular system, and cognitive functions. Importantly, sleep appears to be present throughout the animal kingdom suggesting that it must provide an evolutionary advantage. Among the many possible functions of sleep, the relationship between sleep, and cognition has received a lot of support. We have all experienced the negative cognitive effects associated with a night of sleep deprivation. These can include increased emotional reactivity, poor judgment, deficit in attention, impairment in learning and memory, and obviously increase in daytime sleepiness. Furthermore, many neurological diseases like Alzheimer’s disease often have a sleep disorder component. In some cases, the sleep disorder can exacerbate the progression of the neurological disease. Thus, it is clear that sleep plays an important role for many brain functions. In particular, sleep has been shown to play a positive role in the consolidation of long-term memory while sleep deprivation negatively impacts learning and memory. Importantly, sleep is a behavior that is adapted to an individual’s need and influenced by many external and internal stimuli. In addition to being an adaptive behavior, sleep can also modulate plasticity in the brain at the level of synaptic connections between neurons and neuronal plasticity influences sleep. Understanding how sleep is modulated by internal and external stimuli and how sleep can modulate memory and plasticity is a key question in neuroscience. In order to address this question, several animal models have been developed. Among them, the fruit fly Drosophila melanogaster with its unparalleled genetics has proved to be extremely valuable. In addition to sleep, Drosophila has been shown to be an excellent model to study many complex behaviors, including learning, and memory. This review describes our current knowledge of the relationship between sleep, plasticity, and memory using the fly model.
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Affiliation(s)
- Stephane Dissel
- Department of Molecular Biology and Biochemistry, School of Biological and Chemical Sciences, University of Missouri-Kansas City, Kansas City, MO, United States
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69
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McGaugh SE, Passow CN, Jaggard JB, Stahl BA, Keene AC. Unique transcriptional signatures of sleep loss across independently evolved cavefish populations. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 334:497-510. [PMID: 32351033 DOI: 10.1002/jez.b.22949] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 01/28/2020] [Accepted: 04/04/2020] [Indexed: 12/12/2022]
Abstract
Animals respond to sleep loss with compensatory rebound sleep, and this is thought to be critical for the maintenance of physiological homeostasis. Sleep duration varies dramatically across animal species, but it is not known whether evolutionary differences in sleep duration are associated with differences in sleep homeostasis. The Mexican cavefish, Astyanax mexicanus, has emerged as a powerful model for studying the evolution of sleep. While eyed surface populations of A. mexicanus sleep approximately 8 hr each day, multiple blind cavefish populations have converged on sleep patterns that total as little as 2 hr each day, providing the opportunity to examine whether the evolution of sleep loss is accompanied by changes in sleep homeostasis. Here, we examine the behavioral and molecular response to sleep deprivation across four independent populations of A. mexicanus. Our behavioral analysis indicates that surface fish and all three cavefish populations display robust recovery sleep during the day following nighttime sleep deprivation, suggesting sleep homeostasis remains intact in cavefish. We profiled transcriptome-wide changes associated with sleep deprivation in surface fish and cavefish. While the total number of differentially expressed genes was not greater for the surface population, the surface population exhibited the highest number of uniquely differentially expressed genes than any other population. Strikingly, a majority of the differentially expressed genes are unique to individual cave populations, suggesting unique expression responses are exhibited across independently evolved cavefish populations. Together, these findings suggest sleep homeostasis is intact in cavefish despite a dramatic reduction in overall sleep duration.
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Affiliation(s)
- Suzanne E McGaugh
- Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, Minnesota
| | - Courtney N Passow
- Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, Minnesota
| | - James Brian Jaggard
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida
| | - Bethany A Stahl
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida
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70
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Maldonado E, Rangel-Huerta E, Rodriguez-Salazar E, Pereida-Jaramillo E, Martínez-Torres A. Subterranean life: Behavior, metabolic, and some other adaptations of Astyanax cavefish. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 334:463-473. [PMID: 32346998 DOI: 10.1002/jez.b.22948] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 03/25/2020] [Accepted: 04/04/2020] [Indexed: 12/20/2022]
Abstract
The ability of fishes to adapt to any aquatic environment seems limitless. It is enthralling how new species keep appearing at the deep sea or in subterranean environments. There are close to 230 known species of cavefishes, still today the best-known cavefish is Astyanax mexicanus, a Characid that has become a model organism, and has been studied and scrutinized since 1936. There are two morphotypes for A. mexicanus, a surface fish and a cavefish. The surface fish lives in central and northeastern Mexico and south of the United States, while the cavefish is endemic to the "Sierra del Abra-Tanchipa region" in northeast Mexico. The extensive genetic and genomic analysis depicts a complex origin for Astyanax cavefish, with multiple cave invasions and persistent gene flow among cave populations. The surface founder population prevails in the same region where the caves are. In this review, we focus on both morphotype's main morphological and physiological differences, but mainly in recent discoveries about behavioral and metabolic adaptations for subterranean life. These traits may not be as obvious as the troglomorphic characteristics, but are key to understand how Astyanax cavefish thrives in this environment of perpetual darkness.
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Affiliation(s)
- Ernesto Maldonado
- EvoDevo Research Group, Unidad de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, México
| | - Emma Rangel-Huerta
- EvoDevo Research Group, Unidad de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, México
| | - Elizabeth Rodriguez-Salazar
- EvoDevo Research Group, Unidad de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, México
| | - Elizabeth Pereida-Jaramillo
- Laboratorio de Neurobiología Molecular y Celular, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Santiago de Querétaro, México
| | - Ataulfo Martínez-Torres
- Laboratorio de Neurobiología Molecular y Celular, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Santiago de Querétaro, México
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71
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Abstract
Sleep is a ubiquitous and complex behavior in both its manifestation and regulation. Despite its essential role in maintaining optimal performance, health, and well-being, the genetic mechanisms underlying sleep remain poorly understood. Here, we review the forward genetic approaches undertaken in the last four years to elucidate the genes and gene pathways affecting sleep and its regulation. Despite an increasing number of studies and mining large databases, a coherent picture on “sleep” genes has yet to emerge. We highlight the results achieved by using unbiased genetic screens mainly in humans, mice, and fruit flies with an emphasis on normal sleep and make reference to lessons learned from the circadian field.
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Affiliation(s)
- Maxime Jan
- Centre for Integrative Genomics, University of Lausanne, Lausanne, 1015, Switzerland
| | - Bruce F O'Hara
- Department of Biology, University of Kentucky, Lexington, 40515, USA
| | - Paul Franken
- Centre for Integrative Genomics, University of Lausanne, Lausanne, 1015, Switzerland
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72
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Brown EB, Shah KD, Faville R, Kottler B, Keene AC. Drosophila insulin-like peptide 2 mediates dietary regulation of sleep intensity. PLoS Genet 2020; 16:e1008270. [PMID: 32160200 PMCID: PMC7089559 DOI: 10.1371/journal.pgen.1008270] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 03/23/2020] [Accepted: 12/06/2019] [Indexed: 01/30/2023] Open
Abstract
Sleep is a nearly universal behavior that is regulated by diverse environmental stimuli and physiological states. A defining feature of sleep is a homeostatic rebound following deprivation, where animals compensate for lost sleep by increasing sleep duration and/or sleep depth. The fruit fly, Drosophila melanogaster, exhibits robust recovery sleep following deprivation and represents a powerful model to study neural circuits regulating sleep homeostasis. Numerous neuronal populations have been identified in modulating sleep homeostasis as well as depth, raising the possibility that the duration and quality of recovery sleep is dependent on the environmental or physiological processes that induce sleep deprivation. Here, we find that unlike most pharmacological and environmental manipulations commonly used to restrict sleep, starvation potently induces sleep loss without a subsequent rebound in sleep duration or depth. Both starvation and a sucrose-only diet result in increased sleep depth, suggesting that dietary protein is essential for normal sleep depth and homeostasis. Finally, we find that Drosophila insulin like peptide 2 (Dilp2) is acutely required for starvation-induced changes in sleep depth without regulating the duration of sleep. Flies lacking Dilp2 exhibit a compensatory sleep rebound following starvation-induced sleep deprivation, suggesting Dilp2 promotes resiliency to sleep loss. Together, these findings reveal innate resilience to starvation-induced sleep loss and identify distinct mechanisms that underlie starvation-induced changes in sleep duration and depth. Sleep is nearly universal throughout the animal kingdom and homeostatic regulation represents a defining feature of sleep, where animals compensate for lost sleep by increasing sleep over subsequent time periods. Despite the robustness of this feature, the neural mechanisms regulating recovery from different types of sleep deprivation are not fully understood. Fruit flies provide a powerful model for investigating the genetic regulation of sleep, and like mammals, display robust recovery sleep following deprivation. Here, we find that unlike most stimuli that suppress sleep, sleep deprivation by starvation does not require a homeostatic rebound. These findings are likely due to flies engaging in deeper sleep during the period of partial sleep deprivation, suggesting a natural resilience to starvation-induced sleep loss. This unique resilience to starvation-induced sleep loss is dependent on Drosophila insulin-like peptide 2, revealing a critical role for insulin signaling in regulating interactions between diet and sleep homeostasis.
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Affiliation(s)
- Elizabeth B. Brown
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida, United States of America
| | - Kreesha D. Shah
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida, United States of America
- Wilkes Honors College, Florida Atlantic University, Jupiter, Florida, United States of America
| | | | | | - Alex C. Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida, United States of America
- * E-mail:
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73
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Kowalko J. Utilizing the blind cavefish Astyanax mexicanus to understand the genetic basis of behavioral evolution. J Exp Biol 2020; 223:223/Suppl_1/jeb208835. [DOI: 10.1242/jeb.208835] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
ABSTRACT
Colonization of novel habitats often results in the evolution of diverse behaviors. Comparisons between individuals from closely related populations that have evolved divergent behaviors in different environments can be used to investigate behavioral evolution. However, until recently, functionally connecting genotypes to behavioral phenotypes in these evolutionarily relevant organisms has been difficult. The development of gene editing tools will facilitate functional genetic analysis of genotype–phenotype connections in virtually any organism, and has the potential to significantly transform the field of behavioral genetics when applied to ecologically and evolutionarily relevant organisms. The blind cavefish Astyanax mexicanus provides a remarkable example of evolution associated with colonization of a novel habitat. These fish consist of a single species that includes sighted surface fish that inhabit the rivers of Mexico and southern Texas and at least 29 populations of blind cavefish from the Sierra Del Abra and Sierra de Guatemala regions of Northeast Mexico. Although eye loss and albinism have been studied extensively in A. mexicanus, derived behavioral traits including sleep loss, alterations in foraging and reduction in social behaviors are now also being investigated in this species to understand the genetic and neural basis of behavioral evolution. Astyanax mexicanus has emerged as a powerful model system for genotype–phenotype mapping because surface and cavefish are interfertile. Further, the molecular basis of repeated trait evolution can be examined in this species, as multiple cave populations have independently evolved the same traits. A sequenced genome and the implementation of gene editing in A. mexicanus provides a platform for gene discovery and identification of the contributions of naturally occurring variation to behaviors. This review describes the current knowledge of behavioral evolution in A. mexicanus with an emphasis on the molecular and genetic underpinnings of evolved behaviors. Multiple avenues of new research that can be pursued using gene editing tools are identified, and how these will enhance our understanding of behavioral evolution is discussed.
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Affiliation(s)
- Johanna Kowalko
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
- Program of Neurogenetics, Florida Atlantic University, Jupiter, FL 33458, USA
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74
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Pamboro ELS, Brown EB, Keene AC. Dietary fatty acids promote sleep through a taste-independent mechanism. GENES BRAIN AND BEHAVIOR 2020; 19:e12629. [PMID: 31845509 DOI: 10.1111/gbb.12629] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 12/04/2019] [Accepted: 12/05/2019] [Indexed: 01/28/2023]
Abstract
Consumption of foods that are high in fat contribute to obesity and metabolism-related disorders. Dietary lipids are comprised of triglycerides and fatty acids, and the highly palatable taste of dietary fatty acids promotes food consumption, activates reward centers in mammals and underlies hedonic feeding. Despite the central role of dietary fats in the regulation of food intake and the etiology of metabolic diseases, little is known about how fat consumption regulates sleep. The fruit fly, Drosophila melanogaster, provides a powerful model system for the study of sleep and metabolic traits, and flies potently regulate sleep in accordance with food availability. To investigate the effects of dietary fats on sleep regulation, we have supplemented fatty acids into the diet of Drosophila and measured their effects on sleep and activity. We found that flies fed a diet of hexanoic acid, a medium-chain fatty acid that is a by-product of yeast fermentation, slept more than flies starved on an agar diet. To assess whether dietary fatty acids regulate sleep through the taste system, we assessed sleep in flies with a mutation in the hexanoic acid receptor Ionotropic receptor 56D, which is required for fatty acid taste perception. We found that these flies also sleep more than agar-fed flies when fed a hexanoic acid diet, suggesting the sleep promoting effect of hexanoic acid is not dependent on sensory perception. Taken together, these findings provide a platform to investigate the molecular and neural basis for fatty acid-dependent modulation of sleep.
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Affiliation(s)
- Estelle L S Pamboro
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida
| | - Elizabeth B Brown
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida
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Kumar S, Smith KR, Serrano Negron YL, Harbison ST. Short-Term Memory Deficits in the SLEEP Inbred Panel. Clocks Sleep 2019; 1:471-488. [PMID: 32596662 PMCID: PMC7318870 DOI: 10.3390/clockssleep1040036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Although sleep is heritable and conserved across species, sleep duration varies from individual to individual. A shared genetic architecture between sleep duration and other evolutionarily important traits could explain this variability. Learning and memory are critical traits sharing a genetic architecture with sleep. We wanted to know whether learning and memory would be altered in extreme long or short sleepers. We therefore assessed the short-term learning and memory ability of flies from the Sleep Inbred Panel (SIP), a collection of 39 extreme long- and short-sleeping inbred lines of Drosophila. Neither long nor short sleepers had appreciable learning, in contrast to a moderate-sleeping control. We also examined the response of long and short sleepers to enriched social conditions, a paradigm previously shown to induce morphological changes in the brain. While moderate-sleeping control flies had increased daytime sleep and quantifiable increases in brain structures under enriched social conditions, flies of the Sleep Inbred Panel did not display these changes. The SIP thus emerges as an important model for the relationship between sleep and learning and memory.
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76
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Soto R, Goetting DL, Van Buskirk C. NPR-1 Modulates Plasticity in C. elegans Stress-Induced Sleep. iScience 2019; 19:1037-1047. [PMID: 31522115 PMCID: PMC6745490 DOI: 10.1016/j.isci.2019.08.050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/22/2019] [Accepted: 08/27/2019] [Indexed: 12/15/2022] Open
Abstract
Sleep is beneficial yet antagonistic to critical functions such as foraging and escape, and we aim to understand how these competing drives are functionally integrated. C. elegans, which lives in reduced oxygen environments, engages in developmentally timed sleep (DTS) during larval stage transitions and engages in stress-induced sleep (SIS) during recovery from damaging conditions. Although DTS and SIS use distinct mechanisms to coordinate multiple sleep-associated behaviors, we show that movement quiescence in these sleep states is similarly integrated with the competing drive to avoid oxygen. Furthermore, by manipulating oxygen to deprive animals of SIS, we observe sleep rebound in a wild C. elegans isolate, indicating that sleep debt accrues during oxygen-induced SIS deprivation. Our work suggests that multiple sleep states adopt a common, highly plastic effector of movement quiescence that is suppressed by aversive stimuli and responsive to homeostatic sleep pressure, providing a limited window of opportunity for escape.
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Affiliation(s)
- Rony Soto
- Department of Biology, California State University Northridge, Northridge, CA 91330, USA
| | - Desiree L Goetting
- Department of Biology, California State University Northridge, Northridge, CA 91330, USA
| | - Cheryl Van Buskirk
- Department of Biology, California State University Northridge, Northridge, CA 91330, USA.
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77
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Daywake, an Anti-siesta Gene Linked to a Splicing-Based Thermostat from an Adjoining Clock Gene. Curr Biol 2019; 29:1728-1734.e4. [PMID: 31080079 DOI: 10.1016/j.cub.2019.04.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/26/2019] [Accepted: 04/12/2019] [Indexed: 01/25/2023]
Abstract
Sleep is fundamental to animal survival but is a vulnerable state that also limits how much time can be devoted to critical wake-dependent activities [1]. Although many animals are day-active and sleep at night, they exhibit a midday nap, or "siesta," that can vary in intensity and is usually more prominent on warm days. In humans, the balance between maintaining the wake state or sleeping during the day has important health implications [2], but the mechanisms underlying this dynamic regulation are poorly understood. Using the well-established Drosophila melanogaster animal model to study sleep [3], we identify a new wake-sleep regulator that we term daywake (dyw). dyw encodes a juvenile hormone-binding protein [4] that functions in neurons as a day-specific anti-siesta gene, with little effect on sleep levels during the nighttime or in the absence of light. Remarkably, dyw expression is stimulated in trans via cold-enhanced splicing of the dmpi8 intron [5] from the reverse-oriented but slightly overlapping period (per) clock gene [6]. The functionally integrated dmpi8-dyw genetic unit operates as a "behavioral temperate acclimator" by increasingly counterbalancing siesta-promoting pathways as daily temperatures become cooler and carry reduced risks from daytime heat exposure. While daily patterns of when animals are awake and when they sleep are largely scheduled by the circadian timing system, dyw implicates a less recognized class of modulatory wake-sleep regulators that primarily function to enhance flexibility in wake-sleep preference, a behavioral plasticity that is commonly observed in animals during the midday, raising the possibility of shared mechanisms.
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78
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Churgin MA, Szuperak M, Davis KC, Raizen DM, Fang-Yen C, Kayser MS. Quantitative imaging of sleep behavior in Caenorhabditis elegans and larval Drosophila melanogaster. Nat Protoc 2019; 14:1455-1488. [PMID: 30953041 DOI: 10.1038/s41596-019-0146-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 01/29/2019] [Indexed: 01/04/2023]
Abstract
Sleep is nearly universal among animals, yet remains poorly understood. Recent work has leveraged simple model organisms, such as Caenorhabditis elegans and Drosophila melanogaster larvae, to investigate the genetic and neural bases of sleep. However, manual methods of recording sleep behavior in these systems are labor intensive and low in throughput. To address these limitations, we developed methods for quantitative imaging of individual animals cultivated in custom microfabricated multiwell substrates, and used them to elucidate molecular mechanisms underlying sleep. Here, we describe the steps necessary to design, produce, and image these plates, as well as analyze the resulting behavioral data. We also describe approaches for experimentally manipulating sleep. Following these procedures, after ~2 h of experimental preparation, we are able to simultaneously image 24 C. elegans from the second larval stage to adult stages or 20 Drosophila larvae during the second instar life stage at a spatial resolution of 10 or 27 µm, respectively. Although this system has been optimized to measure activity and quiescence in Caenorhabditis larvae and adults and in Drosophila larvae, it can also be used to assess other behaviors over short or long periods. Moreover, with minor modifications, it can be adapted for the behavioral monitoring of a wide range of small animals.
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Affiliation(s)
- Matthew A Churgin
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Milan Szuperak
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kristen C Davis
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Center for Excellence in Environmental Toxicology (CEET), Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David M Raizen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Chronobiology Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA.,Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew S Kayser
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. .,Chronobiology Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. .,Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. .,Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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79
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Toda H, Shi M, Williams JA, Sehgal A. Genetic Mechanisms Underlying Sleep. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2019; 83:57-61. [PMID: 30936393 DOI: 10.1101/sqb.2018.83.037705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Sleep is important for cognitive ability, and perturbations of sleep are associated with a myriad of brain disorders. However, how sleep promotes health and function during wake is poorly understood. To address the cellular and molecular mechanisms underlying sleep, we use the fruit fly Drosophila melanogaster as a genetic model. Forward genetic approaches in flies were critical for deciphering molecular mechanisms of the circadian clock. Using similar approaches, we and others are gaining insights into the pathways that control sleep amount.
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Affiliation(s)
- Hirofumi Toda
- Howard Hughes Medical Institute, Perelman School of Medicine University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Mi Shi
- Howard Hughes Medical Institute, Perelman School of Medicine University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Julie A Williams
- Howard Hughes Medical Institute, Perelman School of Medicine University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Amita Sehgal
- Howard Hughes Medical Institute, Perelman School of Medicine University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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80
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Abstract
Sleep is a conserved neurobehavioral state observed in animals with sufficiently complex nervous systems and is critical for survival. While the exact function of sleep remains unknown, the lack of sleep can have a range of physiological and behavioral effects. Studies in invertebrates and vertebrates have identified conserved neural mechanisms and cellular pathways in control of sleep, wakefulness and arousal. Methodologies to measure sleep have ranged from EEG recordings in humans and rodents to in-depth analysis of locomotor patterns in flies, fish and worms. Here we focus on sleep measurements using activity monitoring in the highly versatile experimental model system, Drosophila melanogaster, which is amenable to a number of genetic, physiological and behavioral manipulations. Further, we also describe methods used to manipulate sleep and wakefulness to understand the neural regulation of sleep and how organisms balance sleep, wakefulness and behavioral arousal. Sleep as a behavioral state is regulated by a number of factors including food, environmental conditions, and genetic background. The methodologies described here provide, a high-throughput approach to study neural regulation of sleep and factors that affect this complex behavior.
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Affiliation(s)
- Margaret E Driscoll
- Department of Psychological Sciences, University of San Diego, San Diego, USA
| | - Callen Hyland
- Department of Psychological Sciences, University of San Diego, San Diego, USA
| | - Divya Sitaraman
- Department of Psychological Sciences, University of San Diego, San Diego, USA
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81
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Foster RG. There is no mystery to sleep. Psych J 2018; 7:206-208. [DOI: 10.1002/pchj.247] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 08/12/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Russell G. Foster
- Sleep & Circadian Neuroscience Institute (SCNi), Nuffield Laboratory of Ophthalmology & Nuffield Department of Clinical Neurosciences OMPI, Sir William Dunn School; University of Oxford; Oxford UK
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