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Milosavljevic S, Piroli MV, Sandago EJ, Piroli GG, Smith HH, Beggiato S, Frizzell N, Pocivavsek A. Parental kynurenine 3-monooxygenase genotype in mice directs sex-specific behavioral outcomes in offspring. Biol Sex Differ 2025; 16:22. [PMID: 40176166 PMCID: PMC11967062 DOI: 10.1186/s13293-025-00703-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2024] [Accepted: 03/13/2025] [Indexed: 04/04/2025] Open
Abstract
BACKGROUND Disruptions in brain development can impact behavioral traits and increase the risk of neurodevelopmental conditions such as autism spectrum disorder, attention-deficit/hyperactivity disorder (ADHD), schizophrenia, and bipolar disorder, often in sex-specific ways. Dysregulation of the kynurenine pathway (KP) of tryptophan metabolism has been implicated in cognitive and neurodevelopmental disorders. Increased brain kynurenic acid (KYNA), a neuroactive metabolite implicated in cognition and sleep homeostasis, and variations in the Kmo gene, which encodes kynurenine 3-monooxygenase (KMO), have been identified in these patients. We hypothesize that parental Kmo genetics influence KP biochemistry, sleep behavior and brain energy demands, contributing to impairments in cognition and sleep in offspring through the influence of parental genotype and genetic nurture mechanisms. METHODS A mouse model of partial Kmo deficiency, Kmo heterozygous (HET-Kmo+/-), was used to examine brain KMO activity, KYNA levels, and sleep behavior in HET-Kmo+/- compared to wild-type control (WT-Control) mice. Brain mitochondrial respiration was assessed, and KP metabolites and corticosterone levels were measured in breast milk. Behavioral assessments were conducted on wild-type offspring from two parental groups: (i) WT-Control from WT-Control parents, (ii) wild-type Kmo (WT-Kmo+/+) from Kmo heterozygous parents (HET-Kmo+/-). All mice were C57Bl/6J background strain. Adult female and male offspring underwent behavioral testing for learning, memory, anxiety-like behavior and sleep-wake patterns. RESULTS HET-Kmo+/- mice exhibited reduced brain KMO activity, increased KYNA levels, and disrupted sleep architecture and electroencephalogram (EEG) power spectra. Mitochondrial respiration (Complex I and Complex II activity) and electron transport chain protein levels were impaired in the hippocampus of HET-Kmo+/- females. Breast milk from HET-Kmo+/- mothers increased kynurenine exposure during lactation but corticosterone levels were unchanged. Compared to WT-Control offspring, WT-Kmo+/+ females showed impaired spatial learning, heightened anxiety, reduced sleep and abnormal EEG spectral power. WT-Kmo+/+ males had deficits in reversal learning but no sleep disturbances or anxiety-like behaviors. CONCLUSIONS These findings suggest that Kmo deficiency impacts KP biochemistry, sleep behavior, and brain mitochondrial function. Even though WT-Kmo+/+ inherit identical genetic material as WT-Control, their development might be shaped by the parent's physiology, behavior, or metabolic state influenced by their Kmo genotype, leading to phenotypic sex-specific differences in offspring.
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Affiliation(s)
- Snezana Milosavljevic
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Building 1, D26, 6311 Garners Ferry Rd, Columbia, SC, 29209, USA
| | - Maria V Piroli
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Building 1, D26, 6311 Garners Ferry Rd, Columbia, SC, 29209, USA
| | - Emma J Sandago
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Building 1, D26, 6311 Garners Ferry Rd, Columbia, SC, 29209, USA
| | - Gerardo G Piroli
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Building 1, D26, 6311 Garners Ferry Rd, Columbia, SC, 29209, USA
| | - Holland H Smith
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Building 1, D26, 6311 Garners Ferry Rd, Columbia, SC, 29209, USA
| | - Sarah Beggiato
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Norma Frizzell
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Building 1, D26, 6311 Garners Ferry Rd, Columbia, SC, 29209, USA
| | - Ana Pocivavsek
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Building 1, D26, 6311 Garners Ferry Rd, Columbia, SC, 29209, USA.
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Bencze D, Marián M, Szőllősi Á, Simor P, Racsmány M. Increase in slow frequency and decrease in alpha and beta power during post-learning rest predict long-term memory success. Cortex 2025; 183:167-182. [PMID: 39662242 DOI: 10.1016/j.cortex.2024.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 08/26/2024] [Accepted: 11/11/2024] [Indexed: 12/13/2024]
Abstract
Formation of episodic memories is linked to cortico-hippocampal interactions during learning, practice, and post-learning rest, although the role of cortical activity itself in such processes remains elusive. Behaviorally, long-term retention of episodic memories has been shown to be aided by several different practice strategies involving memory reencounters, such as repeated retrieval and repeated study. In a two-session resting state electroencephalography (EEG) experiment, using data from 68 participants, we investigated the electrophysiological predictors of long-term memory success in situations where such reencounters occurred after learning. Participants learned word pairs which were subsequently practiced either by cued recall or repeated studying in a between-subjects design. Participants' cortical activity was recorded before learning (baseline) and after practice during 15-min resting periods. Long-term memory retention after a 7-day period was measured. To assess cortical activity, we analyzed the change in spectral power from the pre-learning baseline to the post-practice resting state recordings. From baseline to post-practice, changes in alpha and beta power were negatively, while slow frequency power change was positively associated with long-term memory performance, regardless of practice strategy. These results are in line with previous observations pointing to the role of specific frequency bands in memory formation and extend them to situations where memory reencounters occur after learning. Our results also highlight that the effectiveness of practice by repeated testing seems to be independent from the beneficial neural mechanisms mirrored by EEG frequency power changes.
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Affiliation(s)
- Dorottya Bencze
- Institute of Cognitive Neuroscience and Psychology, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary; Institute of Psychology, University of Szeged, Szeged, Hungary
| | - Miklós Marián
- Institute of Cognitive Neuroscience and Psychology, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary; Institute of Psychology, University of Szeged, Szeged, Hungary.
| | - Ágnes Szőllősi
- Institute of Cognitive Neuroscience and Psychology, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary; Institute of Psychology, University of Szeged, Szeged, Hungary; Cognitive Medicine Research Group, Competence Centre for Neurocybernetics of the Life Sciences Cluster of the Centre of Excellence for Interdisciplinary Research, Development and Innovation of the University of Szeged, University of Szeged, Szeged, Hungary
| | - Péter Simor
- Institute of Psychology, Eötvös Loránd University, Budapest, Hungary; Institute of Behavioral Sciences, Semmelweis University, Budapest, Hungary
| | - Mihály Racsmány
- Institute of Cognitive Neuroscience and Psychology, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary; Institute of Psychology, University of Szeged, Szeged, Hungary; Cognitive Medicine Research Group, Competence Centre for Neurocybernetics of the Life Sciences Cluster of the Centre of Excellence for Interdisciplinary Research, Development and Innovation of the University of Szeged, University of Szeged, Szeged, Hungary
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3
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Trinh DQ, Mai NH, Pham TD. Insufficient Sleep and Alzheimer's Disease: Potential Approach for Therapeutic Treatment Methods. Brain Sci 2024; 15:21. [PMID: 39851389 PMCID: PMC11763454 DOI: 10.3390/brainsci15010021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2024] [Revised: 12/26/2024] [Accepted: 12/27/2024] [Indexed: 01/26/2025] Open
Abstract
The interaction between Alzheimer's disease (AD) and sleep deprivation has recently gained attention in the scientific literature, and recent advances suggest that AD epidemiology management should coincide with the management of sleeping disorders. This review focuses on the aspects of the mechanisms underlying the link between AD and insufficient sleep with progressing age. We also provide information which could serve as evidence for future treatments of AD from the early stages in connection with sleep disorder medication.
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Affiliation(s)
- Dieu Quynh Trinh
- Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City 700000, Vietnam;
| | - Nhu Huynh Mai
- Faculty of Pharmacy, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City 700000, Vietnam;
| | - Toan Duc Pham
- Faculty of Pharmacy, Ton Duc Thang University, Ho Chi Minh City 700000, Vietnam
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4
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Srinivasan K, Ribeiro TL, Kells P, Plenz D. The recovery of parabolic avalanches in spatially subsampled neuronal networks at criticality. Sci Rep 2024; 14:19329. [PMID: 39164334 PMCID: PMC11335857 DOI: 10.1038/s41598-024-70014-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Accepted: 08/12/2024] [Indexed: 08/22/2024] Open
Abstract
Scaling relationships are key in characterizing complex systems at criticality. In the brain, they are evident in neuronal avalanches-scale-invariant cascades of neuronal activity quantified by power laws. Avalanches manifest at the cellular level as cascades of neuronal groups that fire action potentials simultaneously. Such spatiotemporal synchronization is vital to theories on brain function yet avalanche synchronization is often underestimated when only a fraction of neurons is observed. Here, we investigate biases from fractional sampling within a balanced network of excitatory and inhibitory neurons with all-to-all connectivity and critical branching process dynamics. We focus on how mean avalanche size scales with avalanche duration. For parabolic avalanches, this scaling is quadratic, quantified by the scaling exponent, χ = 2, reflecting rapid spatial expansion of simultaneous neuronal firing over short durations. However, in networks sampled fractionally, χ is significantly lower. We demonstrate that applying temporal coarse-graining and increasing a minimum threshold for coincident firing restores χ = 2, even when as few as 0.1% of neurons are sampled. This correction crucially depends on the network being critical and fails for near sub- and supercritical branching dynamics. Using cellular 2-photon imaging, our approach robustly identifies χ = 2 over a wide parameter regime in ongoing neuronal activity from frontal cortex of awake mice. In contrast, the common 'crackling noise' approach fails to determine χ under similar sampling conditions at criticality. Our findings overcome scaling bias from fractional sampling and demonstrate rapid, spatiotemporal synchronization of neuronal assemblies consistent with scale-invariant, parabolic avalanches at criticality.
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Affiliation(s)
- Keshav Srinivasan
- Section on Critical Brain Dynamics, National Institute of Mental Health, Porter Neuroscience Research Center, Rm 3A-1000, 35 Convent Drive, Bethesda, MD, 20892, USA
| | - Tiago L Ribeiro
- Section on Critical Brain Dynamics, National Institute of Mental Health, Porter Neuroscience Research Center, Rm 3A-1000, 35 Convent Drive, Bethesda, MD, 20892, USA
| | - Patrick Kells
- Section on Critical Brain Dynamics, National Institute of Mental Health, Porter Neuroscience Research Center, Rm 3A-1000, 35 Convent Drive, Bethesda, MD, 20892, USA
| | - Dietmar Plenz
- Section on Critical Brain Dynamics, National Institute of Mental Health, Porter Neuroscience Research Center, Rm 3A-1000, 35 Convent Drive, Bethesda, MD, 20892, USA.
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Martinez JD, Wilson LG, Brancaleone WP, Peterson KG, Popke DS, Garzon VC, Perez Tremble RE, Donnelly MJ, Mendez Ortega SL, Torres D, Shaver JJ, Jiang S, Yang Z, Aton SJ. Hypnotic treatment improves sleep architecture and EEG disruptions and rescues memory deficits in a mouse model of fragile X syndrome. Cell Rep 2024; 43:114266. [PMID: 38787724 PMCID: PMC11910971 DOI: 10.1016/j.celrep.2024.114266] [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: 07/07/2023] [Revised: 12/20/2023] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
Fragile X syndrome (FXS) is associated with disrupted cognition and sleep abnormalities. Sleep loss negatively impacts cognitive function, and one untested possibility is that disrupted cognition in FXS is exacerbated by abnormal sleep. We tested whether ML297, a hypnotic acting on G-protein-activated inward-rectifying potassium (GIRK) channels, could reverse sleep phenotypes and disrupted memory in Fmr1-/y mice. Fmr1-/y mice exhibit reduced non-rapid eye movement (NREM) sleep and fragmented NREM architecture, altered sleep electroencephalogram (EEG) oscillations, and reduced EEG coherence between cortical areas; these are partially reversed following ML297 administration. Treatment following contextual fear or spatial learning restores disrupted memory consolidation in Fmr1-/y mice. During memory recall, Fmr1-/y mice show an altered balance of activity among hippocampal principal neurons vs. parvalbumin-expressing interneurons; this is partially reversed by ML297. Because sleep disruption could impact neurophysiological phenotypes in FXS, augmenting sleep may improve disrupted cognition in this disorder.
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Affiliation(s)
- Jessy D Martinez
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lydia G Wilson
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - William P Brancaleone
- Undergraduate Program in Neuroscience, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kathryn G Peterson
- Undergraduate Program in Neuroscience, University of Michigan, Ann Arbor, MI 48109, USA
| | - Donald S Popke
- Undergraduate Program in Neuroscience, University of Michigan, Ann Arbor, MI 48109, USA
| | - Valentina Caicedo Garzon
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Roxanne E Perez Tremble
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marcus J Donnelly
- Undergraduate Program in Neuroscience, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Daniel Torres
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - James J Shaver
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sha Jiang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhongying Yang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sara J Aton
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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Martinez JD, Brancaleone WP, Peterson KG, Wilson LG, Aton SJ. Atypical hypnotic compound ML297 restores sleep architecture immediately following emotionally valenced learning, to promote memory consolidation and hippocampal network activation during recall. Sleep 2023; 46:zsac301. [PMID: 36510822 PMCID: PMC9995787 DOI: 10.1093/sleep/zsac301] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/28/2022] [Indexed: 12/15/2022] Open
Abstract
Sleep plays a critical role in consolidating many forms of hippocampus-dependent memory. While various classes of hypnotic drugs have been developed in recent years, it remains unknown whether, or how, some of them affect sleep-dependent memory consolidation mechanisms. We find that ML297, a recently developed candidate hypnotic agent targeting a new mechanism (activating GIRK1/2-subunit containing G-protein coupled inwardly rectifying potassium [GIRK] channels), alters sleep architecture in mice over the first 6 hr following a single-trial learning event. Following contextual fear conditioning (CFC), ML297 reversed post-CFC reductions in NREM sleep spindle power and REM sleep amounts and architecture, renormalizing sleep features to what was observed at baseline, prior to CFC. Renormalization of post-CFC REM sleep latency, REM sleep amounts, and NREM spindle power were all associated with improved contextual fear memory (CFM) consolidation. We find that improvements in CFM consolidation due to ML297 are sleep-dependent, and are associated with increased numbers of highly activated dentate gyrus (DG), CA1, and CA3 neurons during CFM recall. Together our findings suggest that GIRK1/2 channel activation restores normal sleep architecture- including REM sleep, which is normally suppressed following CFC-and increases the number of hippocampal neurons incorporated into the CFM engram during memory consolidation.
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Affiliation(s)
- Jessy D Martinez
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - William P Brancaleone
- Undergraduate Program in Neuroscience, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kathryn G Peterson
- Undergraduate Program in Neuroscience, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lydia G Wilson
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sara J Aton
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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7
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B. Szabo A, Cretin B, Gérard F, Curot J, J. Barbeau E, Pariente J, Dahan L, Valton L. Sleep: The Tip of the Iceberg in the Bidirectional Link Between Alzheimer's Disease and Epilepsy. Front Neurol 2022; 13:836292. [PMID: 35481265 PMCID: PMC9035794 DOI: 10.3389/fneur.2022.836292] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
The observation that a pathophysiological link might exist between Alzheimer's disease (AD) and epilepsy dates back to the identification of the first cases of the pathology itself and is now strongly supported by an ever-increasing mountain of literature. An overwhelming majority of data suggests not only a higher prevalence of epilepsy in Alzheimer's disease compared to healthy aging, but also that AD patients with a comorbid epileptic syndrome, even subclinical, have a steeper cognitive decline. Moreover, clinical and preclinical investigations have revealed a marked sleep-related increase in the frequency of epileptic activities. This characteristic might provide clues to the pathophysiological pathways underlying this comorbidity. Furthermore, the preferential sleep-related occurrence of epileptic events opens up the possibility that they might hasten cognitive decline by interfering with the delicately orchestrated synchrony of oscillatory activities implicated in sleep-related memory consolidation. Therefore, we scrutinized the literature for mechanisms that might promote sleep-related epileptic activity in AD and, possibly dementia onset in epilepsy, and we also aimed to determine to what degree and through which processes such events might alter the progression of AD. Finally, we discuss the implications for patient care and try to identify a common basis for methodological considerations for future research and clinical practice.
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Affiliation(s)
- Anna B. Szabo
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
- *Correspondence: Anna B. Szabo
| | - Benjamin Cretin
- Clinical Neuropsychology Unit, Neurology Department, CM2R (Memory Resource and Research Centre), University Hospital of Strasbourg, Strasbourg, France
- CNRS, ICube Laboratory, UMR 7357 and FMTS (Fédération de Médecine Translationnelle de Strasbourg), Team IMIS, University of Strasbourg, Strasbourg, France
- CMRR d'Alsace, Service de Neurologie des Hôpitaux Universitaires de Strasbourg, Pôle Tête et Cou, Strasbourg, France
| | - Fleur Gérard
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
- Neurology Department, Hôpital Purpan Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Jonathan Curot
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
- Neurology Department, Hôpital Purpan Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Emmanuel J. Barbeau
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
| | - Jérémie Pariente
- Neurology Department, Hôpital Purpan Centre Hospitalier Universitaire de Toulouse, Toulouse, France
- Toulouse NeuroImaging Center (ToNIC), INSERM-University of Toulouse Paul Sabatier, Toulouse, France
| | - Lionel Dahan
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Luc Valton
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
- Neurology Department, Hôpital Purpan Centre Hospitalier Universitaire de Toulouse, Toulouse, France
- Luc Valton
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The Effect of Sleep Deprivation and Subsequent Recovery Period on the Synaptic Proteome of Rat Cerebral Cortex. Mol Neurobiol 2022; 59:1301-1319. [PMID: 34988919 PMCID: PMC8857111 DOI: 10.1007/s12035-021-02699-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 12/13/2021] [Indexed: 12/31/2022]
Abstract
Sleep deprivation (SD) is commonplace in the modern way of life and has a substantial social, medical, and human cost. Sleep deprivation induces cognitive impairment such as loss of executive attention, working memory decline, poor emotion regulation, increased reaction times, and higher cognitive functions are particularly vulnerable to sleep loss. Furthermore, SD is associated with obesity, diabetes, cardiovascular diseases, cancer, and a vast majority of psychiatric and neurodegenerative disorders are accompanied by sleep disturbances. Despite the widespread scientific interest in the effect of sleep loss on synaptic function, there is a lack of investigation focusing on synaptic transmission on the proteome level. In the present study, we report the effects of SD and recovery period (RP) on the cortical synaptic proteome in rats. Synaptosomes were isolated after 8 h of SD performed by gentle handling and after 16 h of RP. The purity of synaptosome fraction was validated with western blot and electron microscopy, and the protein abundance alterations were analyzed by mass spectrometry. We observed that SD and RP have a wide impact on neurotransmitter-related proteins at both the presynaptic and postsynaptic membranes. The abundance of synaptic proteins has changed to a greater extent in consequence of SD than during RP: we identified 78 proteins with altered abundance after SD and 39 proteins after the course of RP. Levels of most of the altered proteins were upregulated during SD, while RP showed the opposite tendency, and three proteins (Gabbr1, Anks1b, and Decr1) showed abundance changes with opposite direction after SD and RP. The functional cluster analysis revealed that a majority of the altered proteins is related to signal transduction and regulation, synaptic transmission and synaptic assembly, protein and ion transport, and lipid and fatty acid metabolism, while the interaction network analysis revealed several connections between the significantly altered proteins and the molecular processes of synaptic plasticity or sleep. Our proteomic data implies suppression of SNARE-mediated synaptic vesicle exocytosis and impaired endocytic processes after sleep deprivation. Both SD and RP altered GABA neurotransmission and affected protein synthesis, several regulatory processes and signaling pathways, energy homeostatic processes, and metabolic pathways.
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Reyes-Resina I, Samer S, Kreutz MR, Oelschlegel AM. Molecular Mechanisms of Memory Consolidation That Operate During Sleep. Front Mol Neurosci 2021; 14:767384. [PMID: 34867190 PMCID: PMC8636908 DOI: 10.3389/fnmol.2021.767384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
The role of sleep for brain function has been in the focus of interest for many years. It is now firmly established that sleep and the corresponding brain activity is of central importance for memory consolidation. Less clear are the underlying molecular mechanisms and their specific contribution to the formation of long-term memory. In this review, we summarize the current knowledge of such mechanisms and we discuss the several unknowns that hinder a deeper appreciation of how molecular mechanisms of memory consolidation during sleep impact synaptic function and engram formation.
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Affiliation(s)
- Irene Reyes-Resina
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Sebastian Samer
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Center for Behavioral Brain Sciences, Otto von Guericke University, Magdeburg, Germany.,German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Anja M Oelschlegel
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
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Hijacking of hippocampal-cortical oscillatory coupling during sleep in temporal lobe epilepsy. Epilepsy Behav 2021; 121:106608. [PMID: 31740330 DOI: 10.1016/j.yebeh.2019.106608] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/11/2019] [Accepted: 10/11/2019] [Indexed: 11/21/2022]
Abstract
Memory impairment is the most common cognitive deficit in patients with temporal lobe epilepsy (TLE). This type of epilepsy is currently regarded as a network disease because of its brain-wide alterations in functional connectivity between temporal and extra-temporal regions. In patients with TLE, network dysfunctions can be observed during ictal states, but are also described interictally during rest or sleep. Here, we examined the available literature supporting the hypothesis that hippocampal-cortical coupling during sleep is hijacked in TLE. First, we look at studies showing that the coordination between hippocampal sharp-wave ripples (100-200 Hz), corticothalamic spindles (9-16 Hz), and cortical delta waves (1-4 Hz) during nonrapid eye movement (NREM) sleep is critical for spatial memory consolidation. Then, we reviewed studies showing that animal models of TLE display precise coordination between hippocampal interictal epileptiform discharges (IEDs) and spindle oscillations in the prefrontal cortex. This aberrant oscillatory coupling seems to surpass the physiological ripple-delta-spindle coordination, which could underlie memory consolidation impairments. We also discuss the role of rapid eye movement (REM) sleep for local synaptic plasticity and memory. Sleep episodes of REM provide windows of opportunity for reactivation of expression of immediate early genes (i.e., zif-268 and Arc). Besides, hippocampal theta oscillations during REM sleep seem to be critical for memory consolidation of novel object place recognition task. However, it is still unclear which extend this particular phase of sleep is affected in TLE. In this context, we show some preliminary results from our group, suggesting that hippocampal theta-gamma phase-amplitude coupling is exacerbated during REM in a model of basolateral amygdala fast kindling. In conclusion, there is an increasing body of evidence suggesting that circuits responsible for memory consolidation during sleep seem to be gradually coopted and degraded in TLE. This article is part of the Special Issue "NEWroscience 2018".
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Kuboyama K, Shirakawa Y, Kawada K, Fujii N, Ojima D, Kishimoto Y, Yamamoto T, Yamada MK. Visually cued fear conditioning test for memory impairment related to cortical function. Neuropsychopharmacol Rep 2020; 40:371-375. [PMID: 33089673 PMCID: PMC7722643 DOI: 10.1002/npr2.12146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 08/26/2020] [Accepted: 09/15/2020] [Indexed: 11/10/2022] Open
Abstract
AIM Fear conditioning tests are intended to elucidate a subject's ability to associate a conditioned stimulus with an aversive, unconditioned stimulus, such as footshock. Among these tests, a paradigm related to precise cortical functions would be increasingly important in drug screening for disorders such as schizophrenia and dementia. Therefore, we established a new fear conditioning paradigm using a visual cue in mice. In addition, the validity of the test was evaluated using a genetically engineered mouse, heterozygous deficient in Mdga1 (Mdga1+/-), which is related to schizophrenia. RESULTS Mice were given footshocks associated with a visual cue of moving gratings at training in 25-minute sessions. The mice showed the conditioned response of freezing behavior to the visual stimulus at testing 24 hours after the footshocks. In the test for validation, the Mdga1+/- deficient mice showed significantly less freezing than wild-type mice. CONCLUSION The visually cued fear conditioning paradigm with moving gratings has been established, which is experimentally useful to evaluate animal cortical functions. The validity of the test was confirmed for Mdga1-deficient mice with possible deficiency in cortical functions.
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Affiliation(s)
- Kazuya Kuboyama
- Department of Neuropharmacology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki city, Kagawa, Japan
| | - Yuki Shirakawa
- Department of Neuropharmacology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki city, Kagawa, Japan
| | - Koji Kawada
- Department of Neuropharmacology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki city, Kagawa, Japan
| | - Naoki Fujii
- Department of Neuropharmacology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki city, Kagawa, Japan
| | - Daiki Ojima
- Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Yasushi Kishimoto
- Department of Biophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki city, Kagawa, Japan
| | - Tohru Yamamoto
- Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Maki K Yamada
- Department of Neuropharmacology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki city, Kagawa, Japan
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12
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Lewis PA, Knoblich G, Poe G. How Memory Replay in Sleep Boosts Creative Problem-Solving. Trends Cogn Sci 2019; 22:491-503. [PMID: 29776467 DOI: 10.1016/j.tics.2018.03.009] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/04/2018] [Accepted: 03/20/2018] [Indexed: 11/15/2022]
Abstract
Creative thought relies on the reorganisation of existing knowledge. Sleep is known to be important for creative thinking, but there is a debate about which sleep stage is most relevant, and why. We address this issue by proposing that rapid eye movement sleep, or 'REM', and non-REM sleep facilitate creativity in different ways. Memory replay mechanisms in non-REM can abstract rules from corpuses of learned information, while replay in REM may promote novel associations. We propose that the iterative interleaving of REM and non-REM across a night boosts the formation of complex knowledge frameworks, and allows these frameworks to be restructured, thus facilitating creative thought. We outline a hypothetical computational model which will allow explicit testing of these hypotheses.
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Affiliation(s)
| | - Günther Knoblich
- Department of Cognitive Science, Central European University, Budapest, Hungary
| | - Gina Poe
- Department of Integrative Biology and Physiology, UCLA, LA, USA
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13
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The up and down of sleep: From molecules to electrophysiology. Neurobiol Learn Mem 2019; 160:3-10. [DOI: 10.1016/j.nlm.2018.03.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/04/2018] [Accepted: 03/11/2018] [Indexed: 12/21/2022]
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14
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Seibt J, Frank MG. Primed to Sleep: The Dynamics of Synaptic Plasticity Across Brain States. Front Syst Neurosci 2019; 13:2. [PMID: 30774586 PMCID: PMC6367653 DOI: 10.3389/fnsys.2019.00002] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/09/2019] [Indexed: 11/13/2022] Open
Abstract
It is commonly accepted that brain plasticity occurs in wakefulness and sleep. However, how these different brain states work in concert to create long-lasting changes in brain circuitry is unclear. Considering that wakefulness and sleep are profoundly different brain states on multiple levels (e.g., cellular, molecular and network activation), it is unlikely that they operate exactly the same way. Rather it is probable that they engage different, but coordinated, mechanisms. In this article we discuss how plasticity may be divided across the sleep-wake cycle, and how synaptic changes in each brain state are linked. Our working model proposes that waking experience triggers short-lived synaptic events that are necessary for transient plastic changes and mark (i.e., 'prime') circuits and synapses for further processing in sleep. During sleep, synaptic protein synthesis at primed synapses leads to structural changes necessary for long-term information storage.
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Affiliation(s)
- Julie Seibt
- Surrey Sleep Research Centre, University of Surrey, Guildford, United Kingdom
| | - Marcos G. Frank
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University Spokane, Spokane, WA, United States
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15
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Alcaro A, Carta S. The "Instinct" of Imagination. A Neuro-Ethological Approach to the Evolution of the Reflective Mind and Its Application to Psychotherapy. Front Hum Neurosci 2019; 12:522. [PMID: 30728771 PMCID: PMC6351487 DOI: 10.3389/fnhum.2018.00522] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 12/11/2018] [Indexed: 11/20/2022] Open
Abstract
Recent neuro-psychoanalytic literature has emphasized the view that our subjective identity rests on ancient subcortical neuro-psychic processes expressing unthinking forms of experience, which are “affectively intense without being known” (Solms and Panksepp, 2012). Devoid of internal representations, the emotional states of our “core-Self” (Panksepp, 1998b) are entirely “projected” towards the external world and tend to be discharged through instinctual action-patterns. However, due to the close connections between the subcortical and the cortical midline brain, the emotional drives may also find a way to be reflected within an intrinsic self-referential processing, evident when the organism is not actively engaged with the external world. Thanks to such endogenous functioning, the core-Self emotional dispositions are not overtly executed, but they are organized within coherent dynamic mental structures, called “feeling-toned complexes” by C. G. Jung and “unconscious phantasies” by Melanie Klein. The intrinsic self-referential dynamism of the “brainmind” originated from REM sleep arousal and then evolved in the resting-state activity of a complex of cortico-limbic midline brain structures (CMS), also called Default Mode Network (DMN). From our neuro-ethological perspective, it is sustained by an “introverted” SEEKING activity leading to the subjective exploration of internally constructed virtual scenarios. This “mind wandering” function, implicated in dreaming, fantasy processing, remembering and thinking, is the essence of the imaginative function and constitutes the first form of reflection, where intentions and drives gain a primordial form of conscious (but not self-conscious) representation. During postnatal development, this original (“archetypal”) imaginative function is slowly attuned in a relational “transitional” space and may be expressed first in non-verbal and eventually in abstract-verbal social communicative patterns. Our view has noticeable implications for psychotherapy. Instead of trying to directly modify interpersonal, extrinsic relationships (a top-down approach), dysfunctional emotional-relational patterns may be modified by a process in which the patient is helped to let-go of the perceived feeling-objects in favor of an immersion, via the actual feeling, from the superficial level of perception towards a void feeling-state, empty of images. Only starting from this “anoetic” feeling-state, the deep imaginal creative and re-structuring self-referential activity may be reactivated by a process of spontaneous imagination.
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Affiliation(s)
- Antonio Alcaro
- Department of Psychology, Sapienza University of Rome, Rome, Italy
| | - Stefano Carta
- Department of Pedagogy, Psychology, and Philosophy, Università degli Studi di Cagliari, Cagliari, Italy
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16
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Koyanagi I, Akers KG, Vergara P, Srinivasan S, Sakurai T, Sakaguchi M. Memory consolidation during sleep and adult hippocampal neurogenesis. Neural Regen Res 2019; 14:20-23. [PMID: 30531064 PMCID: PMC6263001 DOI: 10.4103/1673-5374.243695] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In anticipation of the massive burden of neurodegenerative disease within super-aged societies, great efforts have been made to utilize neural stem and progenitor cells for regenerative medicine. The capacity of intrinsic neural stem and progenitor cells to regenerate damaged brain tissue remains unclear, due in part to the lack of knowledge about how these newly born neurons integrate into functional circuitry. As sizable integration of adult-born neurons naturally occurs in the dentate gyrus region of the hippocampus, clarifying the mechanisms of this process could provide insights for applying neural stem and progenitor cells in clinical settings. There is convincing evidence of functional correlations between adult-born neurons and memory consolidation and sleep; therefore, we describe some new advances that were left untouched in our recent review.
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Affiliation(s)
- Iyo Koyanagi
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
| | | | - Pablo Vergara
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
| | - Sakthivel Srinivasan
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
| | - Takeshi Sakurai
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
| | - Masanori Sakaguchi
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
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17
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Rennó-Costa C, da Silva ACC, Blanco W, Ribeiro S. Computational models of memory consolidation and long-term synaptic plasticity during sleep. Neurobiol Learn Mem 2018; 160:32-47. [PMID: 30321652 DOI: 10.1016/j.nlm.2018.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 09/18/2018] [Accepted: 10/11/2018] [Indexed: 12/19/2022]
Abstract
The brain stores memories by persistently changing the connectivity between neurons. Sleep is known to be critical for these changes to endure. Research on the neurobiology of sleep and the mechanisms of long-term synaptic plasticity has provided data in support of various theories of how brain activity during sleep affects long-term synaptic plasticity. The experimental findings - and therefore the theories - are apparently quite contradictory, with some evidence pointing to a role of sleep in the forgetting of irrelevant memories, whereas other results indicate that sleep supports the reinforcement of the most valuable recollections. A unified theoretical framework is in need. Computational modeling and simulation provide grounds for the quantitative testing and comparison of theoretical predictions and observed data, and might serve as a strategy to organize the rather complicated and diverse pool of data and methodologies used in sleep research. This review article outlines the emerging progress in the computational modeling and simulation of the main theories on the role of sleep in memory consolidation.
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Affiliation(s)
- César Rennó-Costa
- BioMe - Bioinformatics Multidisciplinary Environment, Federal University of Rio Grande do Norte, Natal, Brazil; Digital Metropolis Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Ana Cláudia Costa da Silva
- BioMe - Bioinformatics Multidisciplinary Environment, Federal University of Rio Grande do Norte, Natal, Brazil; Digital Metropolis Institute, Federal University of Rio Grande do Norte, Natal, Brazil; Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil; Federal University of Paraiba, João Pessoa, Brazil
| | - Wilfredo Blanco
- BioMe - Bioinformatics Multidisciplinary Environment, Federal University of Rio Grande do Norte, Natal, Brazil; Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil; State University of Rio Grande do Norte, Natal, Brazil
| | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil.
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18
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Almeida-Filho DG, Queiroz CM, Ribeiro S. Memory corticalization triggered by REM sleep: mechanisms of cellular and systems consolidation. Cell Mol Life Sci 2018; 75:3715-3740. [PMID: 30054638 PMCID: PMC11105475 DOI: 10.1007/s00018-018-2886-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 06/27/2018] [Accepted: 07/19/2018] [Indexed: 01/29/2023]
Abstract
Once viewed as a passive physiological state, sleep is a heterogeneous and complex sequence of brain states with essential effects on synaptic plasticity and neuronal functioning. Rapid-eye-movement (REM) sleep has been shown to promote calcium-dependent plasticity in principal neurons of the cerebral cortex, both during memory consolidation in adults and during post-natal development. This article reviews the plasticity mechanisms triggered by REM sleep, with a focus on the emerging role of kinases and immediate-early genes for the progressive corticalization of hippocampus-dependent memories. The body of evidence suggests that memory corticalization triggered by REM sleep is a systemic phenomenon with cellular and molecular causes.
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Affiliation(s)
- Daniel G Almeida-Filho
- Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, 59056-450, Brazil
| | - Claudio M Queiroz
- Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, 59056-450, Brazil
| | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, 59056-450, Brazil.
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19
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Acute and chronic escitalopram alter EEG gamma oscillations differently: relevance to therapeutic effects. Eur J Pharm Sci 2018; 121:347-355. [DOI: 10.1016/j.ejps.2018.06.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 05/24/2018] [Accepted: 06/13/2018] [Indexed: 12/13/2022]
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20
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Brawn TP, Nusbaum HC, Margoliash D. Differential development of retroactive and proactive interference during post-learning wakefulness. ACTA ACUST UNITED AC 2018; 25:325-329. [PMID: 29907640 PMCID: PMC6004066 DOI: 10.1101/lm.046573.117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 04/27/2018] [Indexed: 12/31/2022]
Abstract
Newly encoded, labile memories are prone to disruption during post-learning wakefulness. Here we examine the contributions of retroactive and proactive interference to daytime forgetting on an auditory classification task in a songbird. While both types of interference impair performance, they do not develop concurrently. The retroactive interference of task-B on task-A developed during the learning of task-B, whereas the proactive interference of task-A on task-B emerged during subsequent waking retention. These different time courses indicate an asymmetry in the emergence of retroactive and proactive interference and suggest a mechanistic framework for how different types of interference between new memories develop.
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Affiliation(s)
- Timothy P Brawn
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois 60637, USA.,Department of Psychology, University of Chicago, Chicago, Illinois 60637, USA
| | - Howard C Nusbaum
- Department of Psychology, University of Chicago, Chicago, Illinois 60637, USA
| | - Daniel Margoliash
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois 60637, USA.,Department of Psychology, University of Chicago, Chicago, Illinois 60637, USA
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21
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Cho J, Sypniewski KA, Arai S, Yamada K, Ogawa S, Pavlides C. Fear memory consolidation in sleep requires protein kinase A. Learn Mem 2018; 25:241-246. [PMID: 29661836 PMCID: PMC5903399 DOI: 10.1101/lm.046458.117] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 02/05/2018] [Indexed: 01/30/2023]
Abstract
It is well established that protein kinase A (PKA) is involved in hippocampal dependent memory consolidation. Sleep is also known to play an important role in this process. However, whether sleep-dependent memory consolidation involves PKA activation has not been clearly determined. Using behavioral observation, animals were categorized into sleep and awake groups. We show that intrahippocampal injections of the PKA inhibitor Rp-cAMPs in post-contextual fear conditioning sleep produced a suppression of long-term fear memory, while injections of Rp-cAMPs during an awake state, at a similar time point, had no effect. In contrast, injections of the PKA activator Sp-cAMPs in awake state, rescued sleep deprivation-induced memory impairments. These results suggest that following learning, PKA activation specifically in sleep is required for the consolidation of long-term memory.
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Affiliation(s)
- Jiyeon Cho
- Faculty of Human Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
| | | | - Shoko Arai
- Faculty of Human Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
| | - Kazuo Yamada
- Faculty of Human Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
| | - Sonoko Ogawa
- Faculty of Human Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
| | - Constantine Pavlides
- Faculty of Human Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
- The Rockefeller University, New York, New York 10065, USA
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22
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Maier JG, Piosczyk H, Holz J, Landmann N, Deschler C, Frase L, Kuhn M, Klöppel S, Spiegelhalder K, Sterr A, Riemann D, Feige B, Voderholzer U, Nissen C. Brief periods of NREM sleep do not promote early offline gains but subsequent on-task performance in motor skill learning. Neurobiol Learn Mem 2017; 145:18-27. [DOI: 10.1016/j.nlm.2017.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 07/11/2017] [Accepted: 08/18/2017] [Indexed: 12/27/2022]
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23
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Formation and suppression of acoustic memories during human sleep. Nat Commun 2017; 8:179. [PMID: 28790302 PMCID: PMC5548898 DOI: 10.1038/s41467-017-00071-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/30/2017] [Indexed: 11/09/2022] Open
Abstract
Sleep and memory are deeply related, but the nature of the neuroplastic processes induced by sleep remains unclear. Here, we report that memory traces can be both formed or suppressed during sleep, depending on sleep phase. We played samples of acoustic noise to sleeping human listeners. Repeated exposure to a novel noise during Rapid Eye Movements (REM) or light non-REM (NREM) sleep leads to improvements in behavioral performance upon awakening. Strikingly, the same exposure during deep NREM sleep leads to impaired performance upon awakening. Electroencephalographic markers of learning extracted during sleep confirm a dissociation between sleep facilitating memory formation (light NREM and REM sleep) and sleep suppressing learning (deep NREM sleep). We can trace these neural changes back to transient sleep events, such as spindles for memory facilitation and slow waves for suppression. Thus, highly selective memory processes are active during human sleep, with intertwined episodes of facilitative and suppressive plasticity.Though memory and sleep are related, it is still unclear whether new memories can be formed during sleep. Here, authors show that people could learn new sounds during REM or light non-REM sleep, but that learning was suppressed when sounds were played during deep NREM sleep.
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24
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Abstract
It is possible that one of the essential functions of sleep is to take out the garbage, as it were, erasing and "forgetting" information built up throughout the day that would clutter the synaptic network that defines us. It may also be that this cleanup function of sleep is a general principle of neuroscience, applicable to every creature with a nervous system.
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25
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Constant Light Desynchronizes Olfactory versus Object and Visuospatial Recognition Memory Performance. J Neurosci 2017; 37:3555-3567. [PMID: 28264977 PMCID: PMC5373134 DOI: 10.1523/jneurosci.3213-16.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 01/12/2017] [Accepted: 02/04/2017] [Indexed: 01/03/2023] Open
Abstract
Circadian rhythms optimize physiology and behavior to the varying demands of the 24 h day. The master circadian clock is located in the suprachiasmatic nuclei (SCN) of the hypothalamus and it regulates circadian oscillators in tissues throughout the body to prevent internal desynchrony. Here, we demonstrate for the first time that, under standard 12 h:12 h light/dark (LD) cycles, object, visuospatial, and olfactory recognition performance in C57BL/6J mice is consistently better at midday relative to midnight. However, under repeated exposure to constant light (rLL), recognition performance becomes desynchronized, with object and visuospatial performance better at subjective midday and olfactory performance better at subjective midnight. This desynchrony in behavioral performance is mirrored by changes in expression of the canonical clock genes Period1 and Period2 (Per1 and Per2), as well as the immediate-early gene Fos in the SCN, dorsal hippocampus, and olfactory bulb. Under rLL, rhythmic Per1 and Fos expression is attenuated in the SCN. In contrast, hippocampal gene expression remains rhythmic, mirroring object and visuospatial performance. Strikingly, Per1 and Fos expression in the olfactory bulb is reversed, mirroring the inverted olfactory performance. Temporal desynchrony among these regions does not result in arrhythmicity because core body temperature and exploratory activity rhythms persist under rLL. Our data provide the first demonstration that abnormal lighting conditions can give rise to temporal desynchrony between autonomous circadian oscillators in different regions, with different consequences for performance across different sensory domains. Such a dispersed network of dissociable circadian oscillators may provide greater flexibility when faced with conflicting environmental signals. SIGNIFICANCE STATEMENT A master circadian clock in the suprachiasmatic nuclei (SCN) of the hypothalamus regulates physiology and behavior across the 24 h day by synchronizing peripheral clocks throughout the brain and body. Without the SCN, these peripheral clocks rapidly become desynchronized. Here, we provide a unique demonstration that, under lighting conditions in which the central clock in the SCN is dampened, peripheral oscillators in the hippocampus and olfactory bulb become desynchronized, along with the behavioral processes mediated by these clocks. Multiple clocks that adopt different phase relationships may enable processes occurring in different brain regions to be optimized to specific phases of the 24 h day. Moreover, such a dispersed network of dissociable circadian clocks may provide greater flexibility when faced with conflicting environmental signals (e.g., seasonal changes in photoperiod).
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26
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Differential modulation of global and local neural oscillations in REM sleep by homeostatic sleep regulation. Proc Natl Acad Sci U S A 2017; 114:E1727-E1736. [PMID: 28193862 DOI: 10.1073/pnas.1615230114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Homeostatic rebound in rapid eye movement (REM) sleep normally occurs after acute sleep deprivation, but REM sleep rebound settles on a persistently elevated level despite continued accumulation of REM sleep debt during chronic sleep restriction (CSR). Using high-density EEG in mice, we studied how this pattern of global regulation is implemented in cortical regions with different functions and network architectures. We found that across all areas, slow oscillations repeated the behavioral pattern of persistent enhancement during CSR, whereas high-frequency oscillations showed progressive increases. This pattern followed a common rule despite marked topographic differences. The findings suggest that REM sleep slow oscillations may translate top-down homeostatic control to widely separated brain regions whereas fast oscillations synchronizing local neuronal ensembles escape this global command. These patterns of EEG oscillation changes are interpreted to reconcile two prevailing theories of the function of sleep, synaptic homeostasis and sleep dependent memory consolidation.
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27
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Cholinergic Oculomotor Nucleus Activity Is Induced by REM Sleep Deprivation Negatively Impacting on Cognition. Mol Neurobiol 2016; 54:5721-5729. [PMID: 27660264 DOI: 10.1007/s12035-016-0112-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 09/07/2016] [Indexed: 01/06/2023]
Abstract
Several efforts have been made to understand the involvement of rapid eye movement (REM) sleep for cognitive processes. Consolidation or retention of recognition memories is severely disrupted by REM sleep deprivation (REMSD). In this regard, pedunculopontine tegmental nucleus (PPT) and other brainstem nuclei, such as pontine nucleus (Pn) and oculomotor nucleus (OCM), appear to be candidates to take part in this REM sleep circuitry with potential involvement in cognition. Therefore, the objective of this study was to investigate a possible association between the performance of Wistar rats in a declarative memory and PPT, Pn, and OCM activities after different periods of REMSD. We examined c-Fos and choline acetyltransferase (ChaT) expressions as indicators of neuronal activity as well as a familiarity-based memory test. The animals were distributed in groups: control, REMSD, and sleep rebound (REB). At the end of the different REMSD (24, 48, 72, and 96 h) and REB (24 h) time points, the rats were immediately tested in the object recognition test and then the brains were collected. Results indicated that OCM neurons presented an increased activity, due to ChaT-labeling associated with REMSD that negatively correlated (r = -0.32) with the cognitive performance. This suggests the existence of a cholinergic compensatory mechanism within the OCM during REMSD. We also showed that 24 h of REMSD impacted similarly in memory, compared to longer periods of REMSD. These data extend the notion that REM sleep is influenced by areas other than PPT, i.e., Pn and OCM, which could be key players in both sleep processes and cognition.
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28
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Affiliation(s)
- Bernat Kocsis
- Harvard Medical School, Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
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29
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Maciunas K, Snipas M, Paulauskas N, Bukauskas FF. Reverberation of excitation in neuronal networks interconnected through voltage-gated gap junction channels. ACTA ACUST UNITED AC 2016; 147:273-88. [PMID: 26880752 PMCID: PMC4772373 DOI: 10.1085/jgp.201511488] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 01/05/2016] [Indexed: 11/20/2022]
Abstract
Voltage-dependent gap junction gating contributes to reverberation in neuronal circuits. We combined Hodgkin–Huxley equations and gating models of gap junction (GJ) channels to simulate the spread of excitation in two-dimensional networks composed of neurons interconnected by voltage-gated GJs. Each GJ channel contains two fast and slow gates, each exhibiting current–voltage (I-V) rectification and gating properties that depend on transjunctional voltage (Vj). The data obtained show how junctional conductance (gj), which is necessary for synchronization of the neuronal network, depends on its size and the intrinsic firing rate of neurons. A phase shift between action potentials (APs) of neighboring neurons creates bipolar, short-lasting Vj spikes of approximately ±100 mV that induce Vj gating, leading to a small decay of gj, which can accumulate into larger decays during bursting activity of neurons. We show that I-V rectification of GJs in local regions of the two-dimensional network of neurons can lead to unidirectional AP transfer and consequently to reverberation of excitation. This reverberation can be initiated by a single electrical pulse and terminated by a low-amplitude pulse applied in a specific window of reverberation cycle. Thus, the model accounts for the influence of dynamically modulatable electrical synapses in shaping the function of a neuronal network and the formation of reverberation, which, as proposed earlier, may be important for the development of short-term memory and its consolidation into long-term memory.
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Affiliation(s)
- Kestutis Maciunas
- Institute of Cardiology, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
| | - Mindaugas Snipas
- Institute of Cardiology, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania Department of Mathematical Modelling, Kaunas University of Technology, 51368 Kaunas, Lithuania
| | - Nerijus Paulauskas
- Institute of Cardiology, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
| | - Feliksas F Bukauskas
- Institute of Cardiology, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461
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30
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Negrón-Oyarzo I, Aboitiz F, Fuentealba P. Impaired Functional Connectivity in the Prefrontal Cortex: A Mechanism for Chronic Stress-Induced Neuropsychiatric Disorders. Neural Plast 2016; 2016:7539065. [PMID: 26904302 PMCID: PMC4745936 DOI: 10.1155/2016/7539065] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 11/25/2015] [Accepted: 12/16/2015] [Indexed: 12/20/2022] Open
Abstract
Chronic stress-related psychiatric diseases, such as major depression, posttraumatic stress disorder, and schizophrenia, are characterized by a maladaptive organization of behavioral responses that strongly affect the well-being of patients. Current evidence suggests that a functional impairment of the prefrontal cortex (PFC) is implicated in the pathophysiology of these diseases. Therefore, chronic stress may impair PFC functions required for the adaptive orchestration of behavioral responses. In the present review, we integrate evidence obtained from cognitive neuroscience with neurophysiological research with animal models, to put forward a hypothesis that addresses stress-induced behavioral dysfunctions observed in stress-related neuropsychiatric disorders. We propose that chronic stress impairs mechanisms involved in neuronal functional connectivity in the PFC that are required for the formation of adaptive representations for the execution of adaptive behavioral responses. These considerations could be particularly relevant for understanding the pathophysiology of chronic stress-related neuropsychiatric disorders.
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Affiliation(s)
- Ignacio Negrón-Oyarzo
- Departamento de Psiquiatría, Facultad de Medicina, Centro Interdisciplinario de Neurociencia, Pontificia Universidad Católica de Chile, Avenida Marcoleta No. 391, 8320000 Santiago, Chile
| | - Francisco Aboitiz
- Departamento de Psiquiatría, Facultad de Medicina, Centro Interdisciplinario de Neurociencia, Pontificia Universidad Católica de Chile, Avenida Marcoleta No. 391, 8320000 Santiago, Chile
| | - Pablo Fuentealba
- Departamento de Psiquiatría, Facultad de Medicina, Centro Interdisciplinario de Neurociencia, Pontificia Universidad Católica de Chile, Avenida Marcoleta No. 391, 8320000 Santiago, Chile
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Horton CL, Malinowski JE. Autobiographical memory and hyperassociativity in the dreaming brain: implications for memory consolidation in sleep. Front Psychol 2015; 6:874. [PMID: 26191010 PMCID: PMC4488598 DOI: 10.3389/fpsyg.2015.00874] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/13/2015] [Indexed: 12/17/2022] Open
Abstract
In this paper we argue that autobiographical memory (AM) activity across sleep and wake can provide insight into the nature of dreaming, and vice versa. Activated memories within the sleeping brain reflect one’s personal life history (autobiography). They can appear in largely fragmentary forms and differ from conventional manifestations of episodic memory. Autobiographical memories in dreams can be sampled from non-REM as well as REM periods, which contain fewer episodic references and become more bizarre across the night. Salient fragmented memory features are activated in sleep and re-bound with fragments not necessarily emerging from the same memory, thus de-contextualizing those memories and manifesting as experiences that differ from waking conceptions. The constructive nature of autobiographical recall further encourages synthesis of these hyper-associated images into an episode via recalling and reporting dreams. We use a model of AM to account for the activation of memories in dreams as a reflection of sleep-dependent memory consolidation processes. We focus in particular on the hyperassociative nature of AM during sleep.
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Blanco W, Pereira CM, Cota VR, Souza AC, Rennó-Costa C, Santos S, Dias G, Guerreiro AMG, Tort ABL, Neto AD, Ribeiro S. Synaptic Homeostasis and Restructuring across the Sleep-Wake Cycle. PLoS Comput Biol 2015; 11:e1004241. [PMID: 26020963 PMCID: PMC4447375 DOI: 10.1371/journal.pcbi.1004241] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 03/14/2015] [Indexed: 01/12/2023] Open
Abstract
Sleep is critical for hippocampus-dependent memory consolidation. However, the underlying mechanisms of synaptic plasticity are poorly understood. The central controversy is on whether long-term potentiation (LTP) takes a role during sleep and which would be its specific effect on memory. To address this question, we used immunohistochemistry to measure phosphorylation of Ca2+/calmodulin-dependent protein kinase II (pCaMKIIα) in the rat hippocampus immediately after specific sleep-wake states were interrupted. Control animals not exposed to novel objects during waking (WK) showed stable pCaMKIIα levels across the sleep-wake cycle, but animals exposed to novel objects showed a decrease during subsequent slow-wave sleep (SWS) followed by a rebound during rapid-eye-movement sleep (REM). The levels of pCaMKIIα during REM were proportional to cortical spindles near SWS/REM transitions. Based on these results, we modeled sleep-dependent LTP on a network of fully connected excitatory neurons fed with spikes recorded from the rat hippocampus across WK, SWS and REM. Sleep without LTP orderly rescaled synaptic weights to a narrow range of intermediate values. In contrast, LTP triggered near the SWS/REM transition led to marked swaps in synaptic weight ranking. To better understand the interaction between rescaling and restructuring during sleep, we implemented synaptic homeostasis and embossing in a detailed hippocampal-cortical model with both excitatory and inhibitory neurons. Synaptic homeostasis was implemented by weakening potentiation and strengthening depression, while synaptic embossing was simulated by evoking LTP on selected synapses. We observed that synaptic homeostasis facilitates controlled synaptic restructuring. The results imply a mechanism for a cognitive synergy between SWS and REM, and suggest that LTP at the SWS/REM transition critically influences the effect of sleep: Its lack determines synaptic homeostasis, its presence causes synaptic restructuring.
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Affiliation(s)
- Wilfredo Blanco
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- Department of Computer and Automation, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- Department of Computer Science, State University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Catia M. Pereira
- Edmond and Lily Safra International Institute of Neuroscience of Natal (ELS-IINN), Natal, Rio Grande do Norte, Brazil
| | - Vinicius R. Cota
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- Laboratory of Neuroengineerging and Neuroscience, Federal University of São João Del-Rei, São João Del-Rei, Minas Gerais, Brazil
| | - Annie C. Souza
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - César Rennó-Costa
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Sharlene Santos
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Gabriella Dias
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Ana M. G. Guerreiro
- Department of Biomedical Engineering, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Adriano B. L. Tort
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Adrião D. Neto
- Department of Computer and Automation, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
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Not only … but also: REM sleep creates and NREM Stage 2 instantiates landmark junctions in cortical memory networks. Neurobiol Learn Mem 2015; 122:69-87. [PMID: 25921620 DOI: 10.1016/j.nlm.2015.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 04/16/2015] [Accepted: 04/16/2015] [Indexed: 12/13/2022]
Abstract
This article argues both rapid eye movement (REM) and non-rapid eye movement (NREM) sleep contribute to overnight episodic memory processes but their roles differ. Episodic memory may have evolved from memory for spatial navigation in animals and humans. Equally, mnemonic navigation in world and mental space may rely on fundamentally equivalent processes. Consequently, the basic spatial network characteristics of pathways which meet at omnidirectional nodes or junctions may be conserved in episodic brain networks. A pathway is formally identified with the unidirectional, sequential phases of an episodic memory. In contrast, the function of omnidirectional junctions is not well understood. In evolutionary terms, both animals and early humans undertook tours to a series of landmark junctions, to take advantage of resources (food, water and shelter), whilst trying to avoid predators. Such tours required memory for emotionally significant landmark resource-place-danger associations and the spatial relationships amongst these landmarks. In consequence, these tours may have driven the evolution of both spatial and episodic memory. The environment is dynamic. Resource-place associations are liable to shift and new resource-rich landmarks may be discovered, these changes may require re-wiring in neural networks. To realise these changes, REM may perform an associative, emotional encoding function between memory networks, engendering an omnidirectional landmark junction which is instantiated in the cortex during NREM Stage 2. In sum, REM may preplay associated elements of past episodes (rather than replay individual episodes), to engender an unconscious representation which can be used by the animal on approach to a landmark junction in wake.
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França ASC, Lobão-Soares B, Muratori L, Nascimento G, Winne J, Pereira CM, Jeronimo SMB, Ribeiro S. D2 dopamine receptor regulation of learning, sleep and plasticity. Eur Neuropsychopharmacol 2015; 25:493-504. [PMID: 25778861 DOI: 10.1016/j.euroneuro.2015.01.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 01/08/2015] [Accepted: 01/16/2015] [Indexed: 01/23/2023]
Abstract
Dopamine and sleep have been independently linked with hippocampus-dependent learning. Since D2 dopaminergic transmission is required for the occurrence of rapid-eye-movement (REM) sleep, it is possible that dopamine affects learning by way of changes in post-acquisition REM sleep. To investigate this hypothesis, we first assessed whether D2 dopaminergic modulation in mice affects novel object preference, a hippocampus-dependent task. Animals trained in the dark period, when sleep is reduced, did not improve significantly in performance when tested 24h after training. In contrast, animals trained in the sleep-rich light period showed significant learning after 24h. When injected with the D2 inverse agonist haloperidol immediately after the exploration of novel objects, animals trained in the light period showed reduced novelty preference upon retesting 24h later. Next we investigated whether haloperidol affected the protein levels of plasticity factors shown to be up-regulated in an experience-dependent manner during REM sleep. Haloperidol decreased post-exploration hippocampal protein levels at 3h, 6h and 12h for phosphorylated Ca(2+)/calmodulin-dependent protein kinase II, at 6h for Zif-268; and at 12h for the brain-derived neurotrophic factor. Electrophysiological and kinematic recordings showed a significant decrease in the amount of REM sleep following haloperidol injection, while slow-wave sleep remained unaltered. Importantly, REM sleep decrease across animals was strongly correlated with deficits in novelty preference (Rho=0.56, p=0.012). Altogether, the results suggest that the dopaminergic regulation of REM sleep affects learning by modulating post-training levels of calcium-dependent plasticity factors.
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Affiliation(s)
- A S C França
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), 59056-450 Natal, RN, Brazil
| | - B Lobão-Soares
- Department of Biophysics and Pharmacology, Federal University of Rio Grande do Norte (UFRN), Brazil.
| | - L Muratori
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), 59056-450 Natal, RN, Brazil; Department of Biochemistry, Federal University of Rio Grande do Norte (UFRN), Brazil
| | - G Nascimento
- Department of Biomedical Engineering, Federal University of Rio Grande do Norte (UFRN), Brazil; Edmond and Lily Safra International Institute of Neuroscience of Natal (ELS-IINN), Natal, RN, Brazil
| | - J Winne
- Edmond and Lily Safra International Institute of Neuroscience of Natal (ELS-IINN), Natal, RN, Brazil
| | - C M Pereira
- Edmond and Lily Safra International Institute of Neuroscience of Natal (ELS-IINN), Natal, RN, Brazil
| | - S M B Jeronimo
- Department of Biochemistry, Federal University of Rio Grande do Norte (UFRN), Brazil
| | - S Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), 59056-450 Natal, RN, Brazil.
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Vorster AP, Born J. Sleep and memory in mammals, birds and invertebrates. Neurosci Biobehav Rev 2015; 50:103-19. [DOI: 10.1016/j.neubiorev.2014.09.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 09/24/2014] [Accepted: 09/27/2014] [Indexed: 01/04/2023]
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Calais JB, Ojopi EB, Morya E, Sameshima K, Ribeiro S. Experience-dependent upregulation of multiple plasticity factors in the hippocampus during early REM sleep. Neurobiol Learn Mem 2015; 122:19-27. [PMID: 25626078 DOI: 10.1016/j.nlm.2015.01.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 12/26/2014] [Accepted: 01/05/2015] [Indexed: 11/16/2022]
Abstract
Sleep is beneficial to learning, but the underlying mechanisms remain controversial. The synaptic homeostasis hypothesis (SHY) proposes that the cognitive function of sleep is related to a generalized rescaling of synaptic weights to intermediate levels, due to a passive downregulation of plasticity mechanisms. A competing hypothesis proposes that the active upscaling and downscaling of synaptic weights during sleep embosses memories in circuits respectively activated or deactivated during prior waking experience, leading to memory changes beyond rescaling. Both theories have empirical support but the experimental designs underlying the conflicting studies are not congruent, therefore a consensus is yet to be reached. To advance this issue, we used real-time PCR and electrophysiological recordings to assess gene expression related to synaptic plasticity in the hippocampus and primary somatosensory cortex of rats exposed to novel objects, then kept awake (WK) for 60 min and finally killed after a 30 min period rich in WK, slow-wave sleep (SWS) or rapid-eye-movement sleep (REM). Animals similarly treated but not exposed to novel objects were used as controls. We found that the mRNA levels of Arc, Egr1, Fos, Ppp2ca and Ppp2r2d were significantly increased in the hippocampus of exposed animals allowed to enter REM, in comparison with control animals. Experience-dependent changes during sleep were not significant in the hippocampus for Bdnf, Camk4, Creb1, and Nr4a1, and no differences were detected between exposed and control SWS groups for any of the genes tested. No significant changes in gene expression were detected in the primary somatosensory cortex during sleep, in contrast with previous studies using longer post-stimulation intervals (>180 min). The experience-dependent induction of multiple plasticity-related genes in the hippocampus during early REM adds experimental support to the synaptic embossing theory.
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Affiliation(s)
- Julien Braga Calais
- Laboratório de Neurociências (LIM/27), Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo (USP), Departamento e Instituto de Psiquiatria, São Paulo, Brazil; Laboratório Cesar Timo-Iaria, Instituto de Ensino e Pesquisa, Hospital Sírio-Libanês, São Paulo, Brazil
| | - Elida Benquique Ojopi
- Laboratório de Neurociências (LIM/27), Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo (USP), Departamento e Instituto de Psiquiatria, São Paulo, Brazil
| | - Edgard Morya
- Laboratório Cesar Timo-Iaria, Instituto de Ensino e Pesquisa, Hospital Sírio-Libanês, São Paulo, Brazil; Edmond and Lily Safra International Institute of Neuroscience of Natal (ELS-IINN), Natal, Brazil
| | - Koichi Sameshima
- Laboratório Cesar Timo-Iaria, Instituto de Ensino e Pesquisa, Hospital Sírio-Libanês, São Paulo, Brazil; Departamento de Radiologia e Oncologia, Faculdade de Medicina da Universidade de São Paulo (USP), São Paulo, Brazil.
| | - Sidarta Ribeiro
- Instituto do Cérebro, Universidade Federal do Rio Grande do Norte (UFRN), Natal, Brazil.
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Vyazovskiy VV, Delogu A. NREM and REM Sleep: Complementary Roles in Recovery after Wakefulness. Neuroscientist 2014; 20:203-19. [PMID: 24598308 DOI: 10.1177/1073858413518152] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The overall function of sleep is hypothesized to provide "recovery" after preceding waking activities, thereby ensuring optimal functioning during subsequent wakefulness. However, the functional significance of the temporal dynamics of sleep, manifested in the slow homeostatic process and the alternation between non-rapid eye movement (NREM) and REM sleep remains unclear. We propose that NREM and REM sleep have distinct and complementary contributions to the overall function of sleep. Specifically, we suggest that cortical slow oscillations, occurring within specific functionally interconnected neuronal networks during NREM sleep, enable information processing, synaptic plasticity, and prophylactic cellular maintenance ("recovery process"). In turn, periodic excursions into an activated brain state-REM sleep-appear to be ideally placed to perform "selection" of brain networks, which have benefited from the process of "recovery," based on their offline performance. Such two-stage modus operandi of the sleep process would ensure that its functions are fulfilled according to the current need and in the shortest time possible. Our hypothesis accounts for the overall architecture of normal sleep and opens up new perspectives for understanding pathological conditions associated with abnormal sleep patterns.
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Affiliation(s)
| | - Alessio Delogu
- Department of Neuroscience, Institute of Psychiatry, King's College London, London, UK
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Role of cardiorespiratory synchronization and sleep physiology: effects on membrane potential in the restorative functions of sleep. Sleep Med 2014; 15:279-88. [DOI: 10.1016/j.sleep.2013.10.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 10/18/2013] [Accepted: 10/19/2013] [Indexed: 01/26/2023]
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Grønli J, Soulé J, Bramham CR. Sleep and protein synthesis-dependent synaptic plasticity: impacts of sleep loss and stress. Front Behav Neurosci 2014; 7:224. [PMID: 24478645 PMCID: PMC3896837 DOI: 10.3389/fnbeh.2013.00224] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Accepted: 12/23/2013] [Indexed: 01/08/2023] Open
Abstract
Sleep has been ascribed a critical role in cognitive functioning. Several lines of evidence implicate sleep in the consolidation of synaptic plasticity and long-term memory. Stress disrupts sleep while impairing synaptic plasticity and cognitive performance. Here, we discuss evidence linking sleep to mechanisms of protein synthesis-dependent synaptic plasticity and synaptic scaling. We then consider how disruption of sleep by acute and chronic stress may impair these mechanisms and degrade sleep function.
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Affiliation(s)
- Janne Grønli
- Department of Biological and Medical Psychology, University of Bergen Bergen, Norway ; Norwegian Competence Center for Sleep Disorders, Haukeland University Hospital Bergen, Norway
| | - Jonathan Soulé
- Department of Biological and Medical Psychology, University of Bergen Bergen, Norway
| | - Clive R Bramham
- Department of Biomedicine and KG Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen Bergen, Norway
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Beijamini F, Pereira SIR, Cini FA, Louzada FM. After being challenged by a video game problem, sleep increases the chance to solve it. PLoS One 2014; 9:e84342. [PMID: 24416219 PMCID: PMC3885559 DOI: 10.1371/journal.pone.0084342] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 11/14/2013] [Indexed: 11/18/2022] Open
Abstract
In the past years many studies have demonstrated the role of sleep on memory consolidation. It is known that sleeping after learning a declarative or non-declarative task, is better than remaining awake. Furthermore, there are reports of a possible role for dreams in consolidation of declarative memories. Other studies have reported the effect of naps on memory consolidation. With similar protocols, another set of studies indicated that sleep has a role in creativity and problem-solving. Here we hypothesised that sleep can increase the likelihood of solving problems. After struggling to solve a video game problem, subjects who took a nap (n = 14) were almost twice as likely to solve it when compared to the wake control group (n = 15). It is interesting to note that, in the nap group 9 out 14 subjects engaged in slow-wave sleep (SWS) and all solved the problem. Surprisingly, we did not find a significant involvement of Rapid Eye Movement (REM) sleep in this task. Slow-wave sleep is believed to be crucial for the transfer of memory-related information to the neocortex and implement intentions. Sleep can benefit problem-solving through the generalisation of newly encoded information and abstraction of the gist. In conclusion, our results indicate that sleep, even a nap, can potentiate the solution of problems that involve logical reasoning. Thus, sleep's function seems to go beyond memory consolidation to include managing of everyday-life events.
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Affiliation(s)
- Felipe Beijamini
- Laboratório de Cronobiologia Humana, Departamento de Fisiologia, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
- * E-mail:
| | - Sofia Isabel Ribeiro Pereira
- Laboratório de Cronobiologia Humana, Departamento de Fisiologia, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Felipe Augusto Cini
- Laboratório de Cronobiologia Humana, Departamento de Fisiologia, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Fernando Mazzilli Louzada
- Laboratório de Cronobiologia Humana, Departamento de Fisiologia, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
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Such stuff as dreams are made on? Elaborative encoding, the ancient art of memory, and the hippocampus. Behav Brain Sci 2013; 36:589-607. [PMID: 24304746 DOI: 10.1017/s0140525x12003135] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractThis article argues that rapid eye movement (REM) dreaming is elaborative encoding for episodic memories. Elaborative encoding in REM can, at least partially, be understood through ancient art of memory (AAOM) principles: visualization, bizarre association, organization, narration, embodiment, and location. These principles render recent memories more distinctive through novel and meaningful association with emotionally salient, remote memories. The AAOM optimizes memory performance, suggesting that its principles may predict aspects of how episodic memory is configured in the brain. Integration and segregation are fundamental organizing principles in the cerebral cortex. Episodic memory networks interconnect profusely within the cortex, creating omnidirectional “landmark” junctions. Memories may be integrated at junctions but segregated along connecting network paths that meet at junctions. Episodic junctions may be instantiated during non–rapid eye movement (NREM) sleep after hippocampal associational function during REM dreams. Hippocampal association involves relating, binding, and integrating episodic memories into a mnemonic compositional whole. This often bizarre, composite image has not been present to the senses; it is not “real” because it hyperassociates several memories. During REM sleep, on the phenomenological level, this composite image is experienced as a dream scene. A dream scene may be instantiated as omnidirectional neocortical junction and retained by the hippocampus as an index. On episodic memory retrieval, an external stimulus (or an internal representation) is matched by the hippocampus against its indices. One or more indices then reference the relevant neocortical junctions from which episodic memories can be retrieved. Episodic junctions reach a processing (rather than conscious) level during normal wake to enable retrieval. If this hypothesis is correct, the stuff of dreams is the stuff of memory.
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Ota SM, Moreira KDM, Suchecki D, Oliveira MGM, Tiba PA. Lithium prevents REM sleep deprivation-induced impairments on memory consolidation. Sleep 2013; 36:1677-84. [PMID: 24179301 DOI: 10.5665/sleep.3126] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Pre-training rapid eye movement sleep (REMS) deprivation affects memory acquisition and/or consolidation. It also produces major REMS rebound at the cost of waking and slow wave sleep (SWS). Given that both SWS and REMS appear to be important for memory processes, REMS rebound after training may disrupt the organization of sleep cycles, i.e., excessive amount of REMS and/or little SWS after training could be harmful for memory formation. OBJECTIVE To examine whether lithium, a drug known to increase SWS and reduce REMS, could prevent the memory impairment induced by pre-training sleep deprivation. DESIGN Animals were divided in 2 groups: cage control (CC) and REMS-deprived (REMSDep), and then subdivided into 4 subgroups, treated either with vehicle or 1 of 3 doses of lithium (50, 100, and 150 mg/kg) 2 h before training on the multiple trial inhibitory avoidance task. Animals were tested 48 h later to make sure that the drug had been already metabolized and eliminated. Another set of animals was implanted with electrodes and submitted to the same experimental protocol for assessment of drug-induced sleep-wake changes. SUBJECTS Wistar male rats weighing 300-400 g. RESULTS Sleep deprived rats required more trials to learn the task and still showed a performance deficit during test, except from those treated with 150 mg/kg of lithium, which also reduced the time spent in REM sleep during sleep recovery. CONCLUSION Lithium reduced rapid eye movement sleep and prevented memory impairment induced by sleep deprivation. These results indicate that these phenomena may be related, but cause-effect relationship cannot be ascertained.
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Affiliation(s)
- Simone M Ota
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
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Owens J, Gruber R, Brown T, Corkum P, Cortese S, O'Brien L, Stein M, Weiss M. Future research directions in sleep and ADHD: report of a consensus working group. J Atten Disord 2013; 17:550-64. [PMID: 22982880 DOI: 10.1177/1087054712457992] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE To explore relationships between basic and translational science research regarding sleep and ADHD in children. METHOD A multidisciplinary group of experts in pediatric sleep medicine and ADHD convened in November 2010 to summarize the current literature, delineate knowledge gaps, and formulate recommendations regarding future research directions and priorities. RESULTS Six major research areas of interest were identified: (a) brain centers regulating sleep, arousal, and attention; (b) neurotransmitter systems involved in both sleep and attention regulation; (c) alterations of neural systems regulating sleep in ADHD; (d) phenotypic similarities between behavioral, mood, and cognitive manifestations of insufficient/disrupted sleep and ADHD; (e) hypoarousal and sleepiness in ADHD; and (f) external sleep-wake signals that affect sleep regulation in ADHD. CONCLUSION An enhanced understanding of the complex mechanisms regulating sleep promotion, wakefulness, and attention may contribute to new insights regarding the core impairments in ADHD and lead to the development of new therapies.
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Affiliation(s)
- Judith Owens
- 1George Washington School of Medicine and Health Sciences, Washington, DC, USA
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Perogamvros L, Dang-Vu TT, Desseilles M, Schwartz S. Sleep and dreaming are for important matters. Front Psychol 2013; 4:474. [PMID: 23898315 PMCID: PMC3722492 DOI: 10.3389/fpsyg.2013.00474] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 07/06/2013] [Indexed: 12/24/2022] Open
Abstract
Recent studies in sleep and dreaming have described an activation of emotional and reward systems, as well as the processing of internal information during these states. Specifically, increased activity in the amygdala and across mesolimbic dopaminergic regions during REM sleep is likely to promote the consolidation of memory traces with high emotional/motivational value. Moreover, coordinated hippocampal-striatal replay during NREM sleep may contribute to the selective strengthening of memories for important events. In this review, we suggest that, via the activation of emotional/motivational circuits, sleep and dreaming may offer a neurobehavioral substrate for the offline reprocessing of emotions, associative learning, and exploratory behaviors, resulting in improved memory organization, waking emotion regulation, social skills, and creativity. Dysregulation of such motivational/emotional processes due to sleep disturbances (e.g., insomnia, sleep deprivation) would predispose to reward-related disorders, such as mood disorders, increased risk-taking and compulsive behaviors, and may have major health implications, especially in vulnerable populations.
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Affiliation(s)
- L Perogamvros
- Sleep Laboratory, Division of Neuropsychiatry, Department of Psychiatry, University Hospitals of Geneva Geneva, Switzerland ; Department of Neuroscience, University of Geneva Geneva, Switzerland ; Swiss Center for Affective Sciences, University of Geneva Geneva, Switzerland
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Abstract
Over more than a century of research has established the fact that sleep benefits the retention of memory. In this review we aim to comprehensively cover the field of "sleep and memory" research by providing a historical perspective on concepts and a discussion of more recent key findings. Whereas initial theories posed a passive role for sleep enhancing memories by protecting them from interfering stimuli, current theories highlight an active role for sleep in which memories undergo a process of system consolidation during sleep. Whereas older research concentrated on the role of rapid-eye-movement (REM) sleep, recent work has revealed the importance of slow-wave sleep (SWS) for memory consolidation and also enlightened some of the underlying electrophysiological, neurochemical, and genetic mechanisms, as well as developmental aspects in these processes. Specifically, newer findings characterize sleep as a brain state optimizing memory consolidation, in opposition to the waking brain being optimized for encoding of memories. Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during SWS and transform respective representations for integration into long-term memory. Ensuing REM sleep may stabilize transformed memories. While elaborated with respect to hippocampus-dependent memories, the concept of an active redistribution of memory representations from networks serving as temporary store into long-term stores might hold also for non-hippocampus-dependent memory, and even for nonneuronal, i.e., immunological memories, giving rise to the idea that the offline consolidation of memory during sleep represents a principle of long-term memory formation established in quite different physiological systems.
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Affiliation(s)
- Björn Rasch
- Division of Biopsychology, Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland.
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Bueno-Junior LS, Lopes-Aguiar C, Ruggiero RN, Romcy-Pereira RN, Leite JP. Muscarinic and nicotinic modulation of thalamo-prefrontal cortex synaptic plasticity [corrected] in vivo. PLoS One 2012; 7:e47484. [PMID: 23118873 PMCID: PMC3484139 DOI: 10.1371/journal.pone.0047484] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 09/11/2012] [Indexed: 02/06/2023] Open
Abstract
The mediodorsal nucleus of the thalamus (MD) is a rich source of afferents to the medial prefrontal cortex (mPFC). Dysfunctions in the thalamo-prefrontal connections can impair networks implicated in working memory, some of which are affected in Alzheimer disease and schizophrenia. Considering the importance of the cholinergic system to cortical functioning, our study aimed to investigate the effects of global cholinergic activation of the brain on MD-mPFC synaptic plasticity by measuring the dynamics of long-term potentiation (LTP) and depression (LTD) in vivo. Therefore, rats received intraventricular injections either of the muscarinic agonist pilocarpine (PILO; 40 nmol/µL), the nicotinic agonist nicotine (NIC; 320 nmol/µL), or vehicle. The injections were administered prior to either thalamic high-frequency (HFS) or low-frequency stimulation (LFS). Test pulses were applied to MD for 30 min during baseline and 240 min after HFS or LFS, while field postsynaptic potentials were recorded in the mPFC. The transient oscillatory effects of PILO and NIC were monitored through recording of thalamic and cortical local field potentials. Our results show that HFS did not affect mPFC responses in vehicle-injected rats, but induced a delayed-onset LTP with distinct effects when applied following PILO or NIC. Conversely, LFS induced a stable LTD in control subjects, but was unable to induce LTD when applied after PILO or NIC. Taken together, our findings show distinct modulatory effects of each cholinergic brain activation on MD-mPFC plasticity following HFS and LFS. The LTP-inducing action and long-lasting suppression of cortical LTD induced by PILO and NIC might implicate differential modulation of thalamo-prefrontal functions under low and high input drive.
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Affiliation(s)
- Lezio Soares Bueno-Junior
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Cleiton Lopes-Aguiar
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rafael Naime Ruggiero
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rodrigo Neves Romcy-Pereira
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- * E-mail:
| | - João Pereira Leite
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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48
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Tort ABL, Scheffer-Teixeira R, Souza BC, Draguhn A, Brankačk J. Theta-associated high-frequency oscillations (110-160Hz) in the hippocampus and neocortex. Prog Neurobiol 2012; 100:1-14. [PMID: 23022096 DOI: 10.1016/j.pneurobio.2012.09.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 08/31/2012] [Accepted: 09/14/2012] [Indexed: 12/27/2022]
Abstract
We review recent evidence for a novel type of fast cortical oscillatory activity that occurs circumscribed between 110 and 160Hz, which we refer to as high-frequency oscillations (HFOs). HFOs characteristically occur modulated by theta phase in the hippocampus and neocortex. HFOs can co-occur with gamma oscillations nested in the same theta cycle, in which case they typically peak at different theta phases. Despite the overlapping frequency ranges, HFOs differ from hippocampal ripple oscillations in some key characteristics, including amplitude, region of occurrence, associated behavioral state, and activity time-course (sustained vs intermittent). Recent in vitro evidence suggests that HFOs depend on fast GABAergic transmission and may also depend on axonal gap junctions. The functional role of HFOs is currently unclear. Both hippocampal and neocortical theta-HFO coupling increase during REM sleep, suggesting a role for HFOs in memory processing.
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Affiliation(s)
- Adriano B L Tort
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil.
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Slow wave sleep during a daytime nap is necessary for protection from subsequent interference and long-term retention. Neurobiol Learn Mem 2012; 98:188-96. [DOI: 10.1016/j.nlm.2012.06.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 06/12/2012] [Accepted: 06/18/2012] [Indexed: 11/19/2022]
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Saletin JM, Walker MP. Nocturnal mnemonics: sleep and hippocampal memory processing. Front Neurol 2012; 3:59. [PMID: 22557988 PMCID: PMC3340569 DOI: 10.3389/fneur.2012.00059] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 03/28/2012] [Indexed: 11/20/2022] Open
Abstract
As critical as waking brain function is to learning and memory, an established literature now describes an equally important yet complementary role for sleep in information processing. This overview examines the specific contribution of sleep to human hippocampal memory processing; both the detriments caused by a lack of sleep, and conversely, the proactive benefits that develop following the presence of sleep. First, a role for sleep before learning is discussed, preparing the hippocampus for initial memory encoding. Second, a role for sleep after learning is considered, modulating the post-encoding consolidation of hippocampal-dependent memory. Third, a model is outlined in which these encoding and consolidation operations are symbiotically accomplished, associated with specific NREM sleep physiological oscillations. As a result, the optimal network outcome is achieved: increasing hippocampal independence and hence overnight consolidation, while restoring next-day sparse hippocampal encoding capacity for renewed learning ability upon awakening. Finally, emerging evidence is considered suggesting that, unlike previous conceptions, sleep does not universally consolidate all information. Instead, and based on explicit as well as saliency cues during initial encoding, sleep executes the discriminatory offline consolidation only of select information. Consequently, sleep promotes the targeted strengthening of some memories while actively forgetting others; a proposal with significant theoretical and clinical ramifications.
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Affiliation(s)
- Jared M Saletin
- Sleep and Neuroimaging Laboratory, Department of Psychology, University of California Berkeley, CA, USA
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