1
|
Koga K, Kobayashi K, Tsuda M, Pickering AE, Furue H. Anterior cingulate cross-hemispheric inhibition via the claustrum resolves painful sensory conflict. Commun Biol 2024; 7:330. [PMID: 38491200 PMCID: PMC10943010 DOI: 10.1038/s42003-024-06008-9] [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: 12/08/2022] [Accepted: 03/04/2024] [Indexed: 03/18/2024] Open
Abstract
The anterior cingulate cortex (ACC) responds to noxious and innocuous sensory inputs, and integrates them to coordinate appropriate behavioral reactions. However, the role of the projections of ACC neurons to subcortical areas and their influence on sensory processing are not fully investigated. Here, we identified that ACC neurons projecting to the contralateral claustrum (ACC→contraCLA) preferentially respond to contralateral mechanical sensory stimulation. These sensory responses were enhanced during attending behavior. Optogenetic activation of ACC→contraCLA neurons silenced pyramidal neurons in the contralateral ACC by recruiting local circuit fast-spiking interneuron activation via an excitatory relay in the CLA. This circuit activation suppressed withdrawal behavior to mechanical stimuli ipsilateral to the ACC→contraCLA neurons. Chemogenetic silencing showed that the cross-hemispheric circuit has an important role in the suppression of contralateral nociceptive behavior during sensory-driven attending behavior. Our findings identify a cross-hemispheric cortical-subcortical-cortical arc allowing the brain to give attentional priority to competing innocuous and noxious inputs.
Collapse
Affiliation(s)
- Keisuke Koga
- Department of Neurophysiology, Hyogo Medical University, Nishinomiya, Japan.
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki, Japan
| | - Makoto Tsuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Anthony E Pickering
- Anesthesia, Pain and Critical Care Research, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Hidemasa Furue
- Department of Neurophysiology, Hyogo Medical University, Nishinomiya, Japan.
| |
Collapse
|
2
|
Ihara K, Shikano Y, Kato S, Yagishita S, Tanaka KF, Takata N. A reinforcement learning model with choice traces for a progressive ratio schedule. Front Behav Neurosci 2024; 17:1302842. [PMID: 38268795 PMCID: PMC10806202 DOI: 10.3389/fnbeh.2023.1302842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 12/13/2023] [Indexed: 01/26/2024] Open
Abstract
The progressive ratio (PR) lever-press task serves as a benchmark for assessing goal-oriented motivation. However, a well-recognized limitation of the PR task is that only a single data point, known as the breakpoint, is obtained from an entire session as a barometer of motivation. Because the breakpoint is defined as the final ratio of responses achieved in a PR session, variations in choice behavior during the PR task cannot be captured. We addressed this limitation by constructing four reinforcement learning models: a simple Q-learning model, an asymmetric model with two learning rates, a perseverance model with choice traces, and a perseverance model without learning. These models incorporated three behavioral choices: reinforced and non-reinforced lever presses and void magazine nosepokes, because we noticed that male mice performed frequent magazine nosepokes during PR tasks. The best model was the perseverance model, which predicted a gradual reduction in amplitudes of reward prediction errors (RPEs) upon void magazine nosepokes. We confirmed the prediction experimentally with fiber photometry of extracellular dopamine (DA) dynamics in the ventral striatum of male mice using a fluorescent protein (genetically encoded GPCR activation-based DA sensor: GRABDA2m). We verified application of the model by acute intraperitoneal injection of low-dose methamphetamine (METH) before a PR task, which increased the frequency of magazine nosepokes during the PR session without changing the breakpoint. The perseverance model captured behavioral modulation as a result of increased initial action values, which are customarily set to zero and disregarded in reinforcement learning analysis. Our findings suggest that the perseverance model reveals the effects of psychoactive drugs on choice behaviors during PR tasks.
Collapse
Affiliation(s)
- Keiko Ihara
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Yu Shikano
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
- Department of Biology, Stanford University, Stanford, CA, United States
| | - Sae Kato
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Sho Yagishita
- Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kenji F. Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Norio Takata
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| |
Collapse
|
3
|
Shikano Y, Yagishita S, Tanaka KF, Takata N. Slow-rising and fast-falling dopaminergic dynamics jointly adjust negative prediction error in the ventral striatum. Eur J Neurosci 2023; 58:4502-4522. [PMID: 36843200 DOI: 10.1111/ejn.15945] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 02/22/2023] [Indexed: 02/28/2023]
Abstract
The greater the reward expectations are, the more different the brain's physiological response will be. Although it is well-documented that better-than-expected outcomes are encoded quantitatively via midbrain dopaminergic (DA) activity, it has been less addressed experimentally whether worse-than-expected outcomes are expressed quantitatively as well. We show that larger reward expectations upon unexpected reward omissions are associated with the preceding slower rise and following larger decrease (DA dip) in the DA concentration at the ventral striatum of mice. We set up a lever press task on a fixed ratio (FR) schedule requiring five lever presses as an effort for a food reward (FR5). The mice occasionally checked the food magazine without a reward before completing the task. The percentage of this premature magazine entry (PME) increased as the number of lever presses approached five, showing rising expectations with increasing proximity to task completion, and hence greater reward expectations. Fibre photometry of extracellular DA dynamics in the ventral striatum using a fluorescent protein (genetically encoded GPCR activation-based DA sensor: GRABDA2m ) revealed that the slow increase and fast decrease in DA levels around PMEs were correlated with the PME percentage, demonstrating a monotonic relationship between the DA dip amplitude and degree of expectations. Computational modelling of the lever press task implementing temporal difference errors and state transitions replicated the observed correlation between the PME frequency and DA dip amplitude in the FR5 task. Taken together, these findings indicate that the DA dip amplitude represents the degree of reward expectations monotonically, which may guide behavioural adjustment.
Collapse
Affiliation(s)
- Yu Shikano
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
- Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Sho Yagishita
- Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kenji F Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| | - Norio Takata
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| |
Collapse
|
4
|
Mirabella PN, Fenselau H. Advanced neurobiological tools to interrogate metabolism. Nat Rev Endocrinol 2023; 19:639-654. [PMID: 37674015 DOI: 10.1038/s41574-023-00885-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/24/2023] [Indexed: 09/08/2023]
Abstract
Engineered neurobiological tools for the manipulation of cellular activity, such as chemogenetics and optogenetics, have become a cornerstone of modern neuroscience research. These tools are invaluable for the interrogation of the central control of metabolism as they provide a direct means to establish a causal relationship between brain activity and biological processes at the cellular, tissue and organismal levels. The utility of these methods has grown substantially due to advances in cellular-targeting strategies, alongside improvements in the resolution and potency of such tools. Furthermore, the potential to recapitulate endogenous cellular signalling has been enriched by insights into the molecular signatures and activity dynamics of discrete brain cell types. However, each modulatory tool has a specific set of advantages and limitations; therefore, tool selection and suitability are of paramount importance to optimally interrogate the cellular and circuit-based underpinnings of metabolic outcomes within the organism. Here, we describe the key principles and uses of engineered neurobiological tools. We also highlight inspiring applications and outline critical considerations to be made when using these tools within the field of metabolism research. We contend that the appropriate application of these biotechnological advances will enable the delineation of the central circuitry regulating systemic metabolism with unprecedented potential.
Collapse
Affiliation(s)
- Paul Nicholas Mirabella
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Cologne, Germany
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany
| | - Henning Fenselau
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Cologne, Germany.
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
| |
Collapse
|
5
|
Kato T, Tanaka KF, Natsubori A. Dopamine Receptor Type 2-Expressing Medium Spiny Neurons in the Ventral Lateral Striatum Have a Non-REM Sleep-Induce Function. eNeuro 2023; 10:ENEURO.0327-23.2023. [PMID: 37704366 PMCID: PMC10540673 DOI: 10.1523/eneuro.0327-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023] Open
Abstract
Dopamine receptor type 2-expressing medium spiny neurons (D2-MSNs) in the medial part of the ventral striatum (VS) induce non-REM (NREM) sleep from the wake state in animals. However, it is unclear whether D2-MSNs in the lateral part of the VS (VLS), which is anatomically and functionally different from the medial part of the VS, contribute to sleep-wake regulation. This study aims to clarify whether and how D2-MSNs in the VLS are involved in sleep-wake regulation. Our study found that specifically removing D2-MSNs in the VLS led to an increase in wakefulness time in mice during the dark phase using a diphtheria toxin-mediated cell ablation/dysfunction technique. D2-MSN ablation throughout the VS further increased dark phase wakefulness time. These findings suggest that VLS D2-MSNs may induce sleep during the dark phase with the medial part of the VS. Next, our fiber photometric recordings revealed that the population intracellular calcium (Ca2+) signal in the VLS D2-MSNs increased during the transition from wake to NREM sleep. The mean Ca2+ signal level of VLS D2-MSNs was higher during NREM and REM sleep than during the wake state, supporting their sleep-inducing role. Finally, optogenetic activation of the VLS D2-MSNs during the wake state always induced NREM sleep, demonstrating the causality of VLS D2-MSNs activity with sleep induction. Additionally, activation of the VLS D1-MSNs, counterparts of D2-MSNs, always induced wake from NREM sleep, indicating a wake-promoting role. In conclusion, VLS D2-MSNs could have an NREM sleep-inducing function in coordination with those in the medial VS.
Collapse
Affiliation(s)
- Tomonobu Kato
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
- Faculty of Science and Technology, Keio University, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Kenji F Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Akiyo Natsubori
- Sleep Disorders Project, Tokyo Metropolitan Institute of Medical Science, Setagaya-Ku, Tokyo 156-8506, Japan
| |
Collapse
|
6
|
Del Rey NLG, Trigo-Damas I, Obeso JA, Cavada C, Blesa J. Neuron types in the primate striatum: stereological analysis of projection neurons and interneurons in control and parkinsonian monkeys. Neuropathol Appl Neurobiol 2022; 48:e12812. [PMID: 35274336 DOI: 10.1111/nan.12812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 02/08/2022] [Accepted: 02/12/2022] [Indexed: 11/26/2022]
Abstract
AIMS The striatum is mainly composed of projection neurons. It also contains interneurons, which modulate and control striatal output. The aim of the present study was to assess the percentages of projection neurons and interneuron populations in the striatum of control monkeys and of parkinsonian monkeys. METHODS Unbiased stereology was used to estimate the volume density of every neuron population in the caudate, putamen and ventral striatum of control monkeys and of monkeys treated with MPTP, which results in striatal dopamine depletion. The various neuron population phenotypes were identified by immunohistochemistry. All analyses were performed within the same subjects using similar processing and analysis parameters, thus allowing for reliable data comparisons. RESULTS In control monkeys, the projection neurons, which express the Dopamine-and-cAMP-Regulated-Phosphoprotein, 32-KDa (DARPP-32), were the most abundant: ~86% of the total neurons counted. The interneurons accounted for the remaining 14%. Among the interneurons, those expressing Calretinin were the most abundant (Cr+: ~57%; ~8% of the total striatal neurons counted), followed those expressing Parvalbumin (Pv+: ~18 %; 2.6%), Dinucleotide Phosphate-Diaphorase (NADPH+: ~13 %; 1.8%), Choline Acetyltransferase (ChAT+: ~11%; 1.5%) and Tyrosine Hydroxylase (TH+: ~0.5%; 0.1%). No significant changes in volume densities occurred in any population following dopamine depletion, except for the TH+ interneurons, which increased in parkinsonian non-symptomatic monkeys and even more in symptomatic monkeys. CONCLUSIONS These data are relevant for translational studies targeting specific neuron populations of the striatum. The fact that dopaminergic denervation does not cause neuron loss in any population has potential pathophysiological implications.
Collapse
Affiliation(s)
- Natalia López-González Del Rey
- HM CINAC (Centro Integral de Neurociencias Abarca Campal), Hospital Universitario HM Puerta del Sur, HM Hospitales, Madrid, Spain.,CIBERNED (Center for Networked Biomedical Research on Neurodegenerative Diseases), Instituto Carlos III, Madrid, Spain.,PhD Program in Neuroscience Autónoma de Madrid University-Cajal Institute, Madrid, Spain
| | - Inés Trigo-Damas
- HM CINAC (Centro Integral de Neurociencias Abarca Campal), Hospital Universitario HM Puerta del Sur, HM Hospitales, Madrid, Spain.,CIBERNED (Center for Networked Biomedical Research on Neurodegenerative Diseases), Instituto Carlos III, Madrid, Spain
| | - J A Obeso
- HM CINAC (Centro Integral de Neurociencias Abarca Campal), Hospital Universitario HM Puerta del Sur, HM Hospitales, Madrid, Spain.,CIBERNED (Center for Networked Biomedical Research on Neurodegenerative Diseases), Instituto Carlos III, Madrid, Spain
| | - Carmen Cavada
- PhD Program in Neuroscience Autónoma de Madrid University-Cajal Institute, Madrid, Spain.,Department of Anatomy, Histology and Neuroscience, School of Medicine, Autónoma de Madrid University, Madrid, Spain
| | - Javier Blesa
- HM CINAC (Centro Integral de Neurociencias Abarca Campal), Hospital Universitario HM Puerta del Sur, HM Hospitales, Madrid, Spain.,CIBERNED (Center for Networked Biomedical Research on Neurodegenerative Diseases), Instituto Carlos III, Madrid, Spain
| |
Collapse
|
7
|
Chronic social defeat stress impairs goal-directed behavior through dysregulation of ventral hippocampal activity in male mice. Neuropsychopharmacology 2021; 46:1606-1616. [PMID: 33692477 PMCID: PMC8280175 DOI: 10.1038/s41386-021-00990-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/30/2021] [Accepted: 02/20/2021] [Indexed: 12/12/2022]
Abstract
Chronic stress is a risk factor for a variety of psychiatric disorders, including depression. Although impairments to motivated behavior are a major symptom of clinical depression, little is known about the circuit mechanisms through which stress impairs motivation. Furthermore, research in animal models for depression has focused on impairments to hedonic aspects of motivation, whereas patient studies suggest that impairments to appetitive, goal-directed motivation contribute significantly to motivational impairments in depression. Here, we characterized goal-directed motivation in repeated social defeat stress (R-SDS), a well-established mouse model for depression in male mice. R-SDS impaired the ability to sustain and complete goal-directed behavior in a food-seeking operant lever-press task. Furthermore, stress-exposed mice segregated into susceptible and resilient subpopulations. Interestingly, susceptibility to stress-induced motivational impairments was unrelated to stress-induced social withdrawal, another prominent effect of R-SDS in mouse models. Based on evidence that ventral hippocampus (vHP) modulates sustainment of goal-directed behavior, we monitored vHP activity during the task using fiber photometry. Successful task completion was associated with suppression of ventral hippocampal neural activity. This suppression was diminished after R-SDS in stress-susceptible but not stress-resilient mice. The serotonin selective reuptake inhibitor (SSRI) escitalopram and ketamine both normalized vHP activity during the task and restored motivated behavior. Furthermore, optogenetic vHP inhibition was sufficient to restore motivated behavior after stress. These results identify vHP hyperactivity as a circuit mechanism of stress-induced impairments to goal-directed behavior and a putative biomarker that is sensitive to antidepressant treatments and that differentiates susceptible and resilient individuals.
Collapse
|
8
|
Abe Y, Kwon S, Oishi M, Unekawa M, Takata N, Seki F, Koyama R, Abe M, Sakimura K, Masamoto K, Tomita Y, Okano H, Mushiake H, Tanaka KF. Optical manipulation of local cerebral blood flow in the deep brain of freely moving mice. Cell Rep 2021; 36:109427. [PMID: 34320360 DOI: 10.1016/j.celrep.2021.109427] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/07/2021] [Accepted: 06/29/2021] [Indexed: 11/18/2022] Open
Abstract
An artificial tool for manipulating local cerebral blood flow (CBF) is necessary for understanding how CBF controls brain function. Here, we generate vascular optogenetic tools whereby smooth muscle cells and endothelial cells express optical actuators in the brain. The illumination of channelrhodopsin-2 (ChR2)-expressing mice induces a local reduction in CBF. Photoactivated adenylyl cyclase (PAC) is an optical protein that increases intracellular cyclic adenosine monophosphate (cAMP), and the illumination of PAC-expressing mice induces a local increase in CBF. We target the ventral striatum, determine the temporal kinetics of CBF change, and optimize the illumination intensity to confine the effects to the ventral striatum. We demonstrate the utility of this vascular optogenetic manipulation in freely and adaptively behaving mice and validate the task- and actuator-dependent behavioral readouts. The development of vascular optogenetic animal models will help accelerate research linking vasculature, circuits, and behavior to health and disease.
Collapse
Affiliation(s)
- Yoshifumi Abe
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan; Live Imaging Center, Central Institute for Experimental Animals, Kawasaki 210-0821, Japan
| | - Soojin Kwon
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan; Department of Physiology, Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Mitsuhiro Oishi
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Miyuki Unekawa
- Department of Neurology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Norio Takata
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan; Live Imaging Center, Central Institute for Experimental Animals, Kawasaki 210-0821, Japan
| | - Fumiko Seki
- Live Imaging Center, Central Institute for Experimental Animals, Kawasaki 210-0821, Japan; Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Manabu Abe
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Kazuto Masamoto
- Brain Science Inspired Life Support Research Center, University of Electro-Communications, Tokyo 182-8585, Japan
| | - Yutaka Tomita
- Department of Neurology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Hideyuki Okano
- Live Imaging Center, Central Institute for Experimental Animals, Kawasaki 210-0821, Japan; Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science, Saitama 351-0198, Japan
| | - Hajime Mushiake
- Department of Physiology, Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan.
| |
Collapse
|
9
|
Tsunematsu T, Sakata S, Sanagi T, Tanaka KF, Matsui K. Region-Specific and State-Dependent Astrocyte Ca 2+ Dynamics during the Sleep-Wake Cycle in Mice. J Neurosci 2021; 41:5440-5452. [PMID: 34006590 PMCID: PMC8221592 DOI: 10.1523/jneurosci.2912-20.2021] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 04/06/2021] [Accepted: 05/02/2021] [Indexed: 11/21/2022] Open
Abstract
Neural activity is diverse, and varies depending on brain regions and sleep/wakefulness states. However, whether astrocyte activity differs between sleep/wakefulness states, and whether there are differences in astrocyte activity among brain regions remain poorly understood. Therefore, in this study, we recorded astrocyte intracellular calcium (Ca2+) concentrations of mice during sleep/wakefulness states in the cortex, hippocampus, hypothalamus, cerebellum, and pons using fiber photometry. For this purpose, male transgenic mice expressing the genetically encoded ratiometric Ca2+ sensor YCnano50 specifically in their astrocytes were used. We demonstrated that Ca2+ levels in astrocytes substantially decrease during rapid eye movement (REM) sleep, and increase after the onset of wakefulness. In contrast, differences in Ca2+ levels during non-REM (NREM) sleep were observed among the different brain regions, and no significant decrease was observed in the hypothalamus and pons. Further analyses focusing on the transition between sleep/wakefulness states and correlation analysis with the duration of REM sleep showed that Ca2+ dynamics differs among brain regions, suggesting the existence of several clusters, i.e., the first comprising the cortex and hippocampus, the second comprising the hypothalamus and pons, and the third comprising the cerebellum. Our study thus demonstrated that astrocyte Ca2+ levels change substantially according to sleep/wakefulness states. These changes were consistent in general unlike neural activity. However, we also clarified that Ca2+ dynamics varies depending on the brain region, implying that astrocytes may play various physiological roles in sleep.SIGNIFICANCE STATEMENT Sleep is an instinctive behavior of many organisms. In the previous five decades, the mechanism of the neural circuits controlling sleep/wakefulness states and the neural activities associated with sleep/wakefulness states in various brain regions have been elucidated. However, whether astrocytes, which are a type of glial cell, change their activity during different sleep/wakefulness states was poorly understood. Here, we demonstrated that dynamic changes in astrocyte Ca2+ concentrations occur in the cortex, hippocampus, hypothalamus, cerebellum, and pons of mice during natural sleep. Further analyses demonstrated that Ca2+ dynamics slightly differ among different brain regions, implying that the physiological roles of astrocytes in sleep/wakefulness might vary depending on the brain region.
Collapse
Affiliation(s)
- Tomomi Tsunematsu
- Super-network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
- Advanced Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
| | - Shuzo Sakata
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, United Kingdom
| | - Tomomi Sanagi
- Advanced Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Ko Matsui
- Super-network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| |
Collapse
|