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Lesku JA, Libourel PA, Kelly ML, Hemmi JM, Kerr CC, Collin SP, Radford CA. An electrophysiological correlate of sleep in a shark. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024. [PMID: 38957102 DOI: 10.1002/jez.2846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/11/2024] [Accepted: 06/13/2024] [Indexed: 07/04/2024]
Abstract
Sleep is a prominent physiological state observed across the animal kingdom. Yet, for some animals, our ability to identify sleep can be masked by behaviors otherwise associated with being awake, such as for some sharks that must swim continuously to push oxygenated seawater over their gills to breathe. We know that sleep in buccal pumping sharks with clear rest/activity cycles, such as draughtsboard sharks (Cephaloscyllium isabellum, Bonnaterre, 1788), manifests as a behavioral shutdown, postural relaxation, reduced responsiveness, and a lowered metabolic rate. However, these features of sleep do not lend themselves well to animals that swim nonstop. In addition to video and accelerometry recordings, we tried to explore the electrophysiological correlates of sleep in draughtsboard sharks using electroencephalography (EEG), electromyography, and electrooculography, while monitoring brain temperature. The seven channels of EEG activity had a surprising level of (apparent) instability when animals were swimming, but also when sleeping. The amount of stable EEG signals was too low for replication within- and across individuals. Eye movements were not measurable, owing to instability of the reference electrode. Based on an established behavioral characterization of sleep in draughtsboard sharks, we offer the original finding that muscle tone was strongest during active wakefulness, lower in quietly awake sharks, and lowest in sleeping sharks. We also offer several critical suggestions on how to improve techniques for characterizing sleep electrophysiology in future studies on elasmobranchs, particularly for those that swim continuously. Ultimately, these approaches will provide important insights into the evolutionary confluence of behaviors typically associated with wakefulness and sleep.
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Affiliation(s)
- John A Lesku
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
| | - Paul-Antoine Libourel
- Center for Functional and Evolutionary Ecology, MAD Team, Montpellier, France
- Neuroscience Research Center of Lyon, Sleep Team, Bron, France
| | - Michael L Kelly
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
- Australian Centre for Disease Preparedness, Commonwealth Scientific and Industrial Research Organisation, Geelong, Victoria, Australia
| | - Jan M Hemmi
- School of Biological Sciences, The University of Western Australia, Perth, Western Australia, Australia
- Oceans Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Caroline C Kerr
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
| | - Shaun P Collin
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
- Oceans Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Craig A Radford
- Institute of Marine Science, Leigh Marine Laboratory, The University of Auckland, Auckland, New Zealand
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Norman H, Munson A, Cortese D, Koeck B, Killen SS. The interplay between sleep and ecophysiology, behaviour and responses to environmental change in fish. J Exp Biol 2024; 227:jeb247138. [PMID: 38860399 PMCID: PMC11213526 DOI: 10.1242/jeb.247138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Evidence of behavioural sleep has been observed in every animal species studied to date, but current knowledge of the behaviour, neurophysiology and ecophysiology associated with sleep is concentrated on mammals and birds. Fish are a hugely diverse group that can offer novel insights into a variety of sleep-related behaviours across environments, but the ecophysiological relevance of sleep in fish has been largely overlooked. Here, we systematically reviewed the literature to assess the current breadth of knowledge on fish sleep, and surveyed the diverse physiological effects and behaviours associated with sleep. We also discuss possible ways in which unstudied external factors may alter sleep behaviours. For example, predation risk may alter sleep patterns, as has been shown in mammalian, avian and reptilian species. Other environmental factors - such as water temperature and oxygen availability - have the potential to alter sleep patterns in fish differently than for terrestrial endotherms. Understanding the ecological influences on sleep in fish is vital, as sleep deprivation has the potential to affect waking behaviour and fitness owing to cognitive and physiological impairments, possibly affecting ecological phenomena and sensitivity to environmental stressors in ways that have not been considered.
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Affiliation(s)
- Helena Norman
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Amelia Munson
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Daphne Cortese
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Barbara Koeck
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Shaun S. Killen
- School of Biodiversity, One Health, and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
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Omond SET, Barker RG, Sanislav O, Fisher PR, Annesley SJ, Lesku JA. Oxygen consumption rate of flatworms under the influence of wake- and sleep-promoting neurotransmitters. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024. [PMID: 38801005 DOI: 10.1002/jez.2828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 05/09/2024] [Accepted: 05/09/2024] [Indexed: 05/29/2024]
Abstract
Flatworms are among the best studied animal models for regeneration; however, they also represent an emerging opportunity to investigate other biological processes as well. For instance, flatworms are nocturnal and sleep during the day, a state that is regulated by sleep/wake history and the action of the sleep-promoting neurotransmitter gamma-aminobutyric acid (or GABA). Sleep is widespread across the animal kingdom, where it serves many nonexclusive functions. Notably, sleep saves energy by reducing metabolic rate and by not doing something more energetically taxing. Whether the conservation of energy is apparent in sleeping flatworms is unclear. We measured the oxygen consumption rate (OCR) of flatworms dosed with either (1) GABA (n = 29) which makes flatworms inactive or (2) dopamine (n = 20) which stimulates flatworms to move, or (3) day and night neurotransmitter-free controls (n = 28 and 27, respectively). While OCR did not differ between the day and night, flatworms treated with GABA used less oxygen than those treated with dopamine, and less than the day-time control. Thus, GABA affected flatworm physiology, ostensibly by enforcing energy-conserving sleep. Evidence that dopamine increased metabolism was less strong. This work broadens our understanding of flatworm physiology and expands the phylogenetic applicability of energy conservation as a function of sleep.
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Affiliation(s)
- Shauni E T Omond
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
| | - Robert G Barker
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
| | - Oana Sanislav
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
| | - Paul R Fisher
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
| | - Sarah J Annesley
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
| | - John A Lesku
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
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Mao X, Han D, Guo W, Zhang W, Wang H, Zhang G, Zhang N, Jin L, Nie B, Li H, Song Y, Wu Y, Chang L. Lateralized brunt of sleep deprivation on white matter injury in a rat model of Alzheimer's disease. GeroScience 2024; 46:2295-2315. [PMID: 37940789 PMCID: PMC10828179 DOI: 10.1007/s11357-023-01000-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/25/2023] [Indexed: 11/10/2023] Open
Abstract
Sleep disturbance is a recognized risk factor for Alzheimer's disease (AD), but the underlying micro-pathological evidence remains limited. To bridge this gap, we established an amyloid-β oligomers (AβO)-induced rat model of AD and subjected it to intermittent sleep deprivation (SD). Diffusion tensor imaging (DTI) and transmission electron microscopy were employed to assess white matter (WM) integrity and ultrastructural changes in myelin sheaths. Our findings demonstrated that SD exacerbated AβO-induced cognitive decline. Furthermore, we found SD aggravated AβO-induced asymmetrical impairments in WM, presenting with reductions in tract integrity observed in commissural fibers and association fasciculi, particularly the right anterior commissure, right corpus callosum, and left cingulum. Ultrastructural changes in myelin sheaths within the hippocampus and corpus callosum further confirmed a lateralized effect. Moreover, SD worsened AβO-induced lateralized disruption of the brain structural network, with impairments in critical nodes of the left hemisphere strongly correlated with cognitive dysfunction. This work represents the first identification of a lateralized impact of SD on the mesoscopic network and cognitive deficits in an AD rat model. These findings could deepen our understanding of the complex interplay between sleep disturbance and AD pathology, providing valuable insights into the early progression of the disease, as well as the development of neuroimaging biomarkers for screening early AD patients with self-reported sleep disturbances. Enhanced understanding of these mechanisms may pave the way for targeted interventions to alleviate cognitive decline and improve the quality of life for individuals at risk of or affected by AD.
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Affiliation(s)
- Xin Mao
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Ding Han
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Wensheng Guo
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Wanning Zhang
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Hongqi Wang
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Guitao Zhang
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Ning Zhang
- Department of Neuropsychiatry and Behavioral Neurology and Clinical Psychology, China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Liangyun Jin
- Electron Microscope Room of Central Laboratory, Capital Medical University, Beijing, 100069, China
| | - Binbin Nie
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
| | - Hui Li
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yizhi Song
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yan Wu
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China.
| | - Lirong Chang
- Department of Anatomy, School of Basic Medical Sciences, Capital Medical University, Beijing, China.
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Zaid E, Rainsford FW, Johnsson RD, Valcu M, Vyssotski AL, Meerlo P, Lesku JA. Semelparous marsupials reduce sleep for sex. Curr Biol 2024; 34:606-614.e3. [PMID: 38278151 DOI: 10.1016/j.cub.2023.12.064] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/16/2023] [Accepted: 12/19/2023] [Indexed: 01/28/2024]
Abstract
Sleep is a prominent, seemingly universal animal behavior. Although sleep maintains optimal waking performance, the biological drive to sleep may be incompatible with the life history of some species. In a multi-year study on semelparous marsupials in Australia, we provide the first direct evidence of ecological sleep restriction in a terrestrial mammal. Dusky (Antechinus swainsonii) and agile (A. agilis) antechinus have an unusual reproductive strategy characterized by the synchronous death of all males at the end of their only breeding season. Using accelerometry, electrophysiology, and metabolomics, we show that males, but not females, increase their activity during the breeding season by reducing sleep. In a trade-off between the neurophysiological requirements for sleep and evolutionary necessity for reproduction, strong sexual selection might drive males to sacrifice sleep to increase access to fertile females and ultimately maximize their fitness.
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Affiliation(s)
- Erika Zaid
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia.
| | - Frederick W Rainsford
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
| | - Robin D Johnsson
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia; Department of Psychology, Franklin and Marshall College, Lancaster, PA 17603, USA
| | - Mihai Valcu
- Department of Ornithology, Max Planck Institute for Biological Intelligence, 82319 Seewiesen, Germany
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zurich and Swiss Federal Institute of Technology (ETH), 8057 Zurich, Switzerland
| | - Peter Meerlo
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen 9747 AG, the Netherlands
| | - John A Lesku
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia.
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Ungurean G, Rattenborg NC. A mammal and bird's-eye-view of the pupil during sleep and wakefulness. Eur J Neurosci 2024; 59:584-594. [PMID: 37038095 DOI: 10.1111/ejn.15983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 03/03/2023] [Accepted: 03/30/2023] [Indexed: 04/12/2023]
Abstract
Besides regulating the amount of light that reaches the retina, fluctuations in pupil size also occur in isoluminant conditions during accommodation, during movement and in relation to cognitive workload, attention and emotion. Recent studies in mammals and birds revealed that the pupils are also highly dynamic in the dark during sleep. However, despite exhibiting similar sleep states (rapid eye movement [REM] and non-REM [NREM] sleep), wake and sleep state-dependent changes in pupil size are opposite between mammals and birds, due in part to differences in the type (striated vs. smooth) and control of the iris muscles. Given the link between pupil dynamics and cognitive processes occurring during wakefulness, sleep-related changes in pupil size might indicate when related processes are occurring during sleep. Moreover, the divergent pupillary behaviour observed between mammals and birds raises the possibility that changes in pupil size in birds are a readout of processes not reflected in the mammalian pupil.
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Affiliation(s)
- Gianina Ungurean
- Max Planck Institute for Biological Intelligence, Seewiesen, Germany
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Libourel PA, Lee WY, Achin I, Chung H, Kim J, Massot B, Rattenborg NC. Nesting chinstrap penguins accrue large quantities of sleep through seconds-long microsleeps. Science 2023; 382:1026-1031. [PMID: 38033080 DOI: 10.1126/science.adh0771] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 10/05/2023] [Indexed: 12/02/2023]
Abstract
Microsleeps, the seconds-long interruptions of wakefulness by eye closure and sleep-related brain activity, are dangerous when driving and might be too short to provide the restorative functions of sleep. If microsleeps do fulfill sleep functions, then animals faced with a continuous need for vigilance might resort to this sleep strategy. We investigated electroencephalographically defined sleep in wild chinstrap penguins, at sea and while nesting in Antarctica, constantly exposed to an egg predator and aggression from other penguins. The penguins nodded off >10,000 times per day, engaging in bouts of bihemispheric and unihemispheric slow-wave sleep lasting on average only 4 seconds, but resulting in the accumulation of >11 hours of sleep for each hemisphere. The investment in microsleeps by successfully breeding penguins suggests that the benefits of sleep can accrue incrementally.
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Affiliation(s)
- P-A Libourel
- Neuroscience Research Center of Lyon, Bron, France
| | - W Y Lee
- Korea Polar Research Institute, Incheon, Republic of Korea
| | - I Achin
- Neuroscience Research Center of Lyon, Bron, France
| | - H Chung
- Korea Polar Research Institute, Incheon, Republic of Korea
| | - J Kim
- Cheongju Zoo, Cheongju, Republic of Korea
| | - B Massot
- Lyon Institute of Nanotechnology, Villeurbanne, France
| | - N C Rattenborg
- Avian Sleep Group, Max Planck Institute for Biological Intelligence, Seewiesen, Germany
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Libourel PA, Lesku JA. Sleep: Hemispheres fight for dominance. Curr Biol 2023; 33:R729-R732. [PMID: 37433277 DOI: 10.1016/j.cub.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
A new study shows that bearded dragons have a peculiar way to coordinate sleep state changes between brain hemispheres. The hemisphere that acts first imposes its activity on the other during their REM sleep-like state.
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Affiliation(s)
- Paul-Antoine Libourel
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, SLEEP Team, F-69500, Bron, France.
| | - John A Lesku
- Sleep Ecophysiology Group, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne 3086, Australia.
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Ungurean G, Behroozi M, Böger L, Helluy X, Libourel PA, Güntürkün O, Rattenborg NC. Wide-spread brain activation and reduced CSF flow during avian REM sleep. Nat Commun 2023; 14:3259. [PMID: 37277328 DOI: 10.1038/s41467-023-38669-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 05/03/2023] [Indexed: 06/07/2023] Open
Abstract
Mammalian sleep has been implicated in maintaining a healthy extracellular environment in the brain. During wakefulness, neuronal activity leads to the accumulation of toxic proteins, which the glymphatic system is thought to clear by flushing cerebral spinal fluid (CSF) through the brain. In mice, this process occurs during non-rapid eye movement (NREM) sleep. In humans, ventricular CSF flow has also been shown to increase during NREM sleep, as visualized using functional magnetic resonance imaging (fMRI). The link between sleep and CSF flow has not been studied in birds before. Using fMRI of naturally sleeping pigeons, we show that REM sleep, a paradoxical state with wake-like brain activity, is accompanied by the activation of brain regions involved in processing visual information, including optic flow during flight. We further demonstrate that ventricular CSF flow increases during NREM sleep, relative to wakefulness, but drops sharply during REM sleep. Consequently, functions linked to brain activation during REM sleep might come at the expense of waste clearance during NREM sleep.
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Affiliation(s)
- Gianina Ungurean
- Avian Sleep Group, Max Planck Institute for Biological Intelligence, Seewiesen, Germany.
| | - Mehdi Behroozi
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, Bochum, Germany.
| | - Leonard Böger
- Max-Planck Research Group Neural Information Flow, Max Planck Institute for the Neurobiology of Behavior - caesar, Bonn, Germany
- Max-Planck Research Group Genetics of Behaviour, Max Planck Institute for the Neurobiology of Behavior - caesar, Bonn, Germany
| | - Xavier Helluy
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, Bochum, Germany
- Department of Neurophysiology, Medical Faculty, Ruhr-University Bochum, Bochum, Germany
| | - Paul-Antoine Libourel
- CRNL, SLEEP Team, UMR 5292 CNRS/U1028 INSERM, Université Claude Bernard Lyon 1, Lyon, Bron, France
| | - Onur Güntürkün
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, Bochum, Germany
- Research Center One Health Ruhr, Research Alliance Ruhr, Ruhr-University Bochum, Bochum, Germany
| | - Niels C Rattenborg
- Avian Sleep Group, Max Planck Institute for Biological Intelligence, Seewiesen, Germany
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