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Ono D, Weaver DR, Hastings MH, Honma KI, Honma S, Silver R. The Suprachiasmatic Nucleus at 50: Looking Back, Then Looking Forward. J Biol Rhythms 2024; 39:135-165. [PMID: 38366616 PMCID: PMC7615910 DOI: 10.1177/07487304231225706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
It has been 50 years since the suprachiasmatic nucleus (SCN) was first identified as the central circadian clock and 25 years since the last overview of developments in the field was published in the Journal of Biological Rhythms. Here, we explore new mechanisms and concepts that have emerged in the subsequent 25 years. Since 1997, methodological developments, such as luminescent and fluorescent reporter techniques, have revealed intricate relationships between cellular and network-level mechanisms. In particular, specific neuropeptides such as arginine vasopressin, vasoactive intestinal peptide, and gastrin-releasing peptide have been identified as key players in the synchronization of cellular circadian rhythms within the SCN. The discovery of multiple oscillators governing behavioral and physiological rhythms has significantly advanced our understanding of the circadian clock. The interaction between neurons and glial cells has been found to play a crucial role in regulating these circadian rhythms within the SCN. Furthermore, the properties of the SCN network vary across ontogenetic stages. The application of cell type-specific genetic manipulations has revealed components of the functional input-output system of the SCN and their correlation with physiological functions. This review concludes with the high-risk effort of identifying open questions and challenges that lie ahead.
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Affiliation(s)
- Daisuke Ono
- Stress Recognition and Response, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - David R Weaver
- Department of Neurobiology and NeuroNexus Institute, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Michael H Hastings
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Ken-Ichi Honma
- Research and Education Center for Brain Science, Hokkaido University, Sapporo, Japan
- Center for Sleep and Circadian Rhythm Disorders, Sapporo Hanazono Hospital, Sapporo, Japan
| | - Sato Honma
- Research and Education Center for Brain Science, Hokkaido University, Sapporo, Japan
- Center for Sleep and Circadian Rhythm Disorders, Sapporo Hanazono Hospital, Sapporo, Japan
| | - Rae Silver
- Stress Recognition and Response, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Neuroscience & Behavior, Barnard College and Department of Psychology, Columbia University, New York City, New York, USA
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Yao Y, Silver R. Mutual Shaping of Circadian Body-Wide Synchronization by the Suprachiasmatic Nucleus and Circulating Steroids. Front Behav Neurosci 2022; 16:877256. [PMID: 35722187 PMCID: PMC9200072 DOI: 10.3389/fnbeh.2022.877256] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/11/2022] [Indexed: 11/18/2022] Open
Abstract
Background Steroids are lipid hormones that reach bodily tissues through the systemic circulation, and play a major role in reproduction, metabolism, and homeostasis. All of these functions and steroids themselves are under the regulation of the circadian timing system (CTS) and its cellular/molecular underpinnings. In health, cells throughout the body coordinate their daily activities to optimize responses to signals from the CTS and steroids. Misalignment of responses to these signals produces dysfunction and underlies many pathologies. Questions Addressed To explore relationships between the CTS and circulating steroids, we examine the brain clock located in the suprachiasmatic nucleus (SCN), the daily fluctuations in plasma steroids, the mechanisms producing regularly recurring fluctuations, and the actions of steroids on their receptors within the SCN. The goal is to understand the relationship between temporal control of steroid secretion and how rhythmic changes in steroids impact the SCN, which in turn modulate behavior and physiology. Evidence Surveyed The CTS is a multi-level organization producing recurrent feedback loops that operate on several time scales. We review the evidence showing that the CTS modulates the timing of secretions from the level of the hypothalamus to the steroidogenic gonadal and adrenal glands, and at specific sites within steroidogenic pathways. The SCN determines the timing of steroid hormones that then act on their cognate receptors within the brain clock. In addition, some compartments of the body-wide CTS are impacted by signals derived from food, stress, exercise etc. These in turn act on steroidogenesis to either align or misalign CTS oscillators. Finally this review provides a comprehensive exploration of the broad contribution of steroid receptors in the SCN and how these receptors in turn impact peripheral responses. Conclusion The hypothesis emerging from the recognition of steroid receptors in the SCN is that mutual shaping of responses occurs between the brain clock and fluctuating plasma steroid levels.
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Affiliation(s)
- Yifan Yao
- Department of Psychology, Columbia University, New York City, NY, United States
- *Correspondence: Yifan Yao,
| | - Rae Silver
- Department of Psychology, Columbia University, New York City, NY, United States
- Department of Neuroscience, Barnard College, New York City, NY, United States
- Department of Psychology, Barnard College, New York City, NY, United States
- Department of Pathology and Cell Biology, Graduate School, Columbia University Irving Medical Center, New York City, NY, United States
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Li Y, Zhang Z. Enhanced Laterality Index: A Novel Measure for Hemispheric Asymmetry. JOURNAL OF HEALTHCARE ENGINEERING 2022; 2022:8997108. [PMID: 35529543 PMCID: PMC9076328 DOI: 10.1155/2022/8997108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/30/2022] [Accepted: 02/25/2022] [Indexed: 11/17/2022]
Abstract
During sleep, the two hemispheres display asymmetries in their activation pattern. Various hemispheric asymmetry measures have been utilized in existing works. Nevertheless, all these measures have one common problem that they would merely take one representative quantity into account when evaluating the functional asymmetry. However, there is a complex series of information exchanges between the two cerebral hemispheres, and only considering one quantity inevitably leads to one-sided or even incorrect conclusions. Consequently, to address the limitation of conventional laterality indices, we propose the so-called enhanced laterality index (ELI), which considers multiple measures of functional asymmetries. Normal sleep and obstructive sleep apnea electroencephalograms (EEGs) from 21 subjects collected in the clinical acquisition system are applied, and two representative quantities are considered simultaneously in this paper. We measure the signal complexity by using fuzzy entropy, and the signal strength is evaluated by calculating EEG energy. The difference of ELI is demonstrated by the comparison with the traditional laterality index (LI) in evaluating the functional asymmetry during sleep.
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Affiliation(s)
- Yuwen Li
- School of Instrument Science and Engineering, Southeast University, Nanjing 210000, China
| | - Zhimin Zhang
- Science and Technology on Information Systems Engineering Laboratory, The 28th Research Institute of CETC, Nanjing 210000, China
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Ono D, Mukai Y, Hung CJ, Chowdhury S, Sugiyama T, Yamanaka A. The mammalian circadian pacemaker regulates wakefulness via CRF neurons in the paraventricular nucleus of the hypothalamus. SCIENCE ADVANCES 2020; 6:eabd0384. [PMID: 33158870 PMCID: PMC7673716 DOI: 10.1126/sciadv.abd0384] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/23/2020] [Indexed: 05/29/2023]
Abstract
In mammals, the daily rhythms of physiological functions are timed by the central circadian clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Although the importance of the SCN for the regulation of sleep/wakefulness has been suggested, little is known about the neuronal projections from the SCN, which regulate sleep/wakefulness. Here, we show that corticotropin-releasing factor (CRF) neurons in the hypothalamic paraventricular nucleus mediate circadian rhythms in the SCN and regulate wakefulness. Optogenetic activation of CRF neurons promoted wakefulness through orexin/hypocretin neurons in the lateral hypothalamus. In vivo Ca2+ recording showed that CRF neurons were active at the initiation of wakefulness. Furthermore, chemogenetic suppression and ablation of CRF neurons decreased locomotor activity and time in wakefulness. Last, a combination of optical manipulation and Ca2+ imaging revealed that neuronal activity of CRF neurons was negatively regulated by GABAergic neurons in the SCN. Our findings provide notable insights into circadian regulation of sleep/wakefulness in mammals.
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Affiliation(s)
- Daisuke Ono
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- CREST, JST, Honcho Kawaguchi, Saitama 332-0012, Japan
| | - Yasutaka Mukai
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- CREST, JST, Honcho Kawaguchi, Saitama 332-0012, Japan
- JSPS Research Fellowship for Young Scientists, Tokyo 102-0083, Japan
| | - Chi Jung Hung
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- CREST, JST, Honcho Kawaguchi, Saitama 332-0012, Japan
- JSPS Research Fellowship for Young Scientists, Tokyo 102-0083, Japan
| | - Srikanta Chowdhury
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- CREST, JST, Honcho Kawaguchi, Saitama 332-0012, Japan
| | | | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- CREST, JST, Honcho Kawaguchi, Saitama 332-0012, Japan
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Good CH, Brager AJ, Capaldi VF, Mysliwiec V. Sleep in the United States Military. Neuropsychopharmacology 2020; 45:176-191. [PMID: 31185484 PMCID: PMC6879759 DOI: 10.1038/s41386-019-0431-7] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/23/2019] [Accepted: 05/31/2019] [Indexed: 02/07/2023]
Abstract
The military lifestyle often includes continuous operations whether in training or deployed environments. These stressful environments present unique challenges for service members attempting to achieve consolidated, restorative sleep. The significant mental and physical derangements caused by degraded metabolic, cardiovascular, skeletomuscular, and cognitive health often result from insufficient sleep and/or circadian misalignment. Insufficient sleep and resulting fatigue compromises personal safety, mission success, and even national security. In the long-term, chronic insufficient sleep and circadian rhythm disorders have been associated with other sleep disorders (e.g., insomnia, obstructive sleep apnea, and parasomnias). Other physiologic and psychologic diagnoses such as post-traumatic stress disorder, cardiovascular disease, and dementia have also been associated with chronic, insufficient sleep. Increased co-morbidity and mortality are compounded by traumatic brain injury resulting from blunt trauma, blast exposure, and highly physically demanding tasks under load. We present the current state of science in human and animal models specific to service members during- and post-military career. We focus on mission requirements of night shift work, sustained operations, and rapid re-entrainment to time zones. We then propose targeted pharmacological and non-pharmacological countermeasures to optimize performance that are mission- and symptom-specific. We recognize a critical gap in research involving service members, but provide tailored interventions for military health care providers based on the large body of research in health care and public service workers.
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Affiliation(s)
- Cameron H. Good
- 0000 0001 2151 958Xgrid.420282.ePhysical Scientist, US Army Research Laboratory, Aberdeen Proving Ground, MD, 21005 USA
| | - Allison J. Brager
- 0000 0001 0036 4726grid.420210.5Sleep Research Center, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD 20910 USA
| | - Vincent F. Capaldi
- 0000 0001 0036 4726grid.420210.5Department of Behavioral Biology Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, Silver Spring, MD 20910 USA
| | - Vincent Mysliwiec
- 0000 0004 0467 8038grid.461685.8San Antonio Military Health System, Department of Sleep Medicine, JBSA, Lackland, TX 78234 USA
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Interhemispheric Brain Switching Correlates with Severity of Sleep-Disordered Breathing for Obstructive Sleep Apnea Patients. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9081568] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
(1) Background: Alternating interhemispheric slow-wave activity during sleep is well-established in birds and cetaceans, but its investigation in humans has been largely neglected. (2) Methods: Fuzzy entropy was used to calculate a laterality index (LI) from C3 and C4 EEG channels. The subjects were grouped according to an apnoea-hypopnoea index (AHI) for statistical analyses: Group A AHI < 15 (mild); Group B 15 ≤ AHI < 30 (moderate); Group C AHI ≥ 30 (severe). The LI distribution was analysed to characterise the brain activity variation in both hemispheres, and the cross-zero switching rate was given statistical tests to find the correlations with the severity of obstructive sleep apnea and sleep states, i.e., wake (W), light sleep (LS), deep sleep (DS), and REM. (3) Results: EEG brain switching activity was observed in all sleep stages, and the LI distribution shows that, for obstructive sleep apnea patients, the interhemispheric asymmetry of brain activity is more obvious than healthy people. A one-way ANOVA revealed a significant difference of switching rate among three groups (F(2,95) = 7.23, p = 0.0012), with Group C shows the least, and also a significant difference among four sleep stages (F(3,94) = 5.09, p = 0.0026), with REM the highest. (4) Conclusions: The alternating interhemispheric activity is confirmed ubiquitous for humans during sleep, and sleep-disordered breathing intends to exacerbate the interhemispheric asymmetry.
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Grossberg S, Kishnan D. Neural Dynamics of Autistic Repetitive Behaviors and Fragile X Syndrome: Basal Ganglia Movement Gating and mGluR-Modulated Adaptively Timed Learning. Front Psychol 2018; 9:269. [PMID: 29593596 PMCID: PMC5859312 DOI: 10.3389/fpsyg.2018.00269] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 02/19/2018] [Indexed: 11/13/2022] Open
Abstract
This article develops the iSTART neural model that proposes how specific imbalances in cognitive, emotional, timing, and motor processes that involve brain regions like prefrontal cortex, temporal cortex, amygdala, hypothalamus, hippocampus, and cerebellum may interact together to cause behavioral symptoms of autism. These imbalances include underaroused emotional depression in the amygdala/hypothalamus, learning of hyperspecific recognition categories that help to cause narrowly focused attention in temporal and prefrontal cortices, and breakdowns of adaptively timed motivated attention and motor circuits in the hippocampus and cerebellum. The article expands the model's explanatory range by, first, explaining recent data about Fragile X syndrome (FXS), mGluR, and trace conditioning; and, second, by explaining distinct causes of stereotyped behaviors in individuals with autism. Some of these stereotyped behaviors, such as an insistence on sameness and circumscribed interests, may result from imbalances in the cognitive and emotional circuits that iSTART models. These behaviors may be ameliorated by operant conditioning methods. Other stereotyped behaviors, such as repetitive motor behaviors, may result from imbalances in how the direct and indirect pathways of the basal ganglia open or close movement gates, respectively. These repetitive behaviors may be ameliorated by drugs that augment D2 dopamine receptor responses or reduce D1 dopamine receptor responses. The article also notes the ubiquitous role of gating by basal ganglia loops in regulating all the functions that iSTART models.
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Affiliation(s)
- Stephen Grossberg
- Center for Adaptive Systems, Graduate Program in Cognitive and Neural Systems, Departments of Mathematics & Statistics, Psychological & Brain Sciences, and Biomedical Engineering, Boston University, Boston, MA, United States
| | - Devika Kishnan
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
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8
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Albers HE, Walton JC, Gamble KL, McNeill JK, Hummer DL. The dynamics of GABA signaling: Revelations from the circadian pacemaker in the suprachiasmatic nucleus. Front Neuroendocrinol 2017; 44:35-82. [PMID: 27894927 PMCID: PMC5225159 DOI: 10.1016/j.yfrne.2016.11.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 10/16/2016] [Accepted: 11/22/2016] [Indexed: 12/31/2022]
Abstract
Virtually every neuron within the suprachiasmatic nucleus (SCN) communicates via GABAergic signaling. The extracellular levels of GABA within the SCN are determined by a complex interaction of synthesis and transport, as well as synaptic and non-synaptic release. The response to GABA is mediated by GABAA receptors that respond to both phasic and tonic GABA release and that can produce excitatory as well as inhibitory cellular responses. GABA also influences circadian control through the exclusively inhibitory effects of GABAB receptors. Both GABA and neuropeptide signaling occur within the SCN, although the functional consequences of the interactions of these signals are not well understood. This review considers the role of GABA in the circadian pacemaker, in the mechanisms responsible for the generation of circadian rhythms, in the ability of non-photic stimuli to reset the phase of the pacemaker, and in the ability of the day-night cycle to entrain the pacemaker.
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Affiliation(s)
- H Elliott Albers
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States.
| | - James C Walton
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - John K McNeill
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Daniel L Hummer
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Department of Psychology, Morehouse College, Atlanta, GA 30314, United States
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9
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Evans JA. Collective timekeeping among cells of the master circadian clock. J Endocrinol 2016; 230:R27-49. [PMID: 27154335 PMCID: PMC4938744 DOI: 10.1530/joe-16-0054] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/06/2016] [Indexed: 01/09/2023]
Abstract
The suprachiasmatic nucleus (SCN) of the anterior hypothalamus is the master circadian clock that coordinates daily rhythms in behavior and physiology in mammals. Like other hypothalamic nuclei, the SCN displays an impressive array of distinct cell types characterized by differences in neurotransmitter and neuropeptide expression. Individual SCN neurons and glia are able to display self-sustained circadian rhythms in cellular function that are regulated at the molecular level by a 24h transcriptional-translational feedback loop. Remarkably, SCN cells are able to harmonize with one another to sustain coherent rhythms at the tissue level. Mechanisms of cellular communication in the SCN network are not completely understood, but recent progress has provided insight into the functional roles of several SCN signaling factors. This review discusses SCN organization, how intercellular communication is critical for maintaining network function, and the signaling mechanisms that play a role in this process. Despite recent progress, our understanding of SCN circuitry and coupling is far from complete. Further work is needed to map SCN circuitry fully and define the signaling mechanisms that allow for collective timekeeping in the SCN network.
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Affiliation(s)
- Jennifer A Evans
- Department of Biomedical SciencesMarquette University, Milwaukee, WI, USA
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10
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Evans JA, Gorman MR. In synch but not in step: Circadian clock circuits regulating plasticity in daily rhythms. Neuroscience 2016; 320:259-80. [PMID: 26861419 DOI: 10.1016/j.neuroscience.2016.01.072] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 01/26/2016] [Accepted: 01/27/2016] [Indexed: 11/16/2022]
Abstract
The suprachiasmatic nucleus (SCN) is a network of neural oscillators that program daily rhythms in mammalian behavior and physiology. Over the last decade much has been learned about how SCN clock neurons coordinate together in time and space to form a cohesive population. Despite this insight, much remains unknown about how SCN neurons communicate with one another to produce emergent properties of the network. Here we review the current understanding of communication among SCN clock cells and highlight a collection of formal assays where changes in SCN interactions provide for plasticity in the waveform of circadian rhythms in behavior. Future studies that pair analytical behavioral assays with modern neuroscience techniques have the potential to provide deeper insight into SCN circuit mechanisms.
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Affiliation(s)
- J A Evans
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA.
| | - M R Gorman
- Department of Psychology, University of San Diego, La Jolla, CA, USA
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11
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Dattolo T, Coomans CP, van Diepen HC, Patton DF, Power S, Antle MC, Meijer JH, Mistlberger RE. Neural activity in the suprachiasmatic circadian clock of nocturnal mice anticipating a daytime meal. Neuroscience 2015; 315:91-103. [PMID: 26701294 DOI: 10.1016/j.neuroscience.2015.12.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/22/2015] [Accepted: 12/08/2015] [Indexed: 01/10/2023]
Abstract
Circadian rhythms in mammals are regulated by a system of circadian oscillators that includes a light-entrainable pacemaker in the suprachiasmatic nucleus (SCN) and food-entrainable oscillators (FEOs) elsewhere in the brain and body. In nocturnal rodents, the SCN promotes sleep in the day and wake at night, while FEOs promote an active state in anticipation of a predictable daily meal. For nocturnal animals to anticipate a daytime meal, wake-promoting signals from FEOs must compete with sleep-promoting signals from the SCN pacemaker. One hypothesis is that FEOs impose a daily rhythm of inhibition on SCN output that is timed to permit the expression of activity prior to a daytime meal. This hypothesis predicts that SCN activity should decrease prior to the onset of anticipatory activity and remain suppressed through the scheduled mealtime. To assess the hypothesis, neural activity in the SCN of mice anticipating a 4-5-h daily meal in the light period was measured using FOS immunohistochemistry and in vivo multiple unit electrophysiology. SCN FOS, quantified by optical density, was significantly reduced at the expected mealtime in food-anticipating mice with access to a running disk, compared to ad libitum-fed and acutely fasted controls. Group differences were not significant when FOS was quantified by other methods, or in mice without running disks. SCN electrical activity was markedly decreased during locomotion in some mice but increased in others. Changes in either direction were concurrent with locomotion, were not specific to food anticipation, and were not sustained during longer pauses. Reduced FOS indicates a net suppression of SCN activity that may depend on the intensity or duration of locomotion. The timing of changes in SCN activity relative to locomotion suggests that any effect of FEOs on SCN output is mediated indirectly, by feedback from neural or systemic correlates of locomotion.
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Affiliation(s)
- T Dattolo
- Department of Psychology, Simon Fraser University, BC, Canada
| | - C P Coomans
- Leiden University Medical Center, Leiden, Netherlands
| | | | - D F Patton
- Department of Psychology, Simon Fraser University, BC, Canada
| | - S Power
- Department of Psychology, Simon Fraser University, BC, Canada
| | - M C Antle
- University of Calgary, Calgary, AB, Canada
| | - J H Meijer
- Leiden University Medical Center, Leiden, Netherlands
| | - R E Mistlberger
- Department of Psychology, Simon Fraser University, BC, Canada.
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12
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Feng Z, Zhong YJ, Wang L, Wei TQ. Resuscitation therapy for traumatic brain injury-induced coma in rats: mechanisms of median nerve electrical stimulation. Neural Regen Res 2015; 10:594-8. [PMID: 26170820 PMCID: PMC4424752 DOI: 10.4103/1673-5374.155433] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2014] [Indexed: 11/30/2022] Open
Abstract
In this study, rats were put into traumatic brain injury-induced coma and treated with median nerve electrical stimulation. We explored the wake-promoting effect, and possible mechanisms, of median nerve electrical stimulation. Electrical stimulation upregulated the expression levels of orexin-A and its receptor OX1R in the rat prefrontal cortex. Orexin-A expression gradually increased with increasing stimulation, while OX1R expression reached a peak at 12 hours and then decreased. In addition, after the OX1R antagonist, SB334867, was injected into the brain of rats after traumatic brain injury, fewer rats were restored to consciousness, and orexin-A and OXIR expression in the prefrontal cortex was downregulated. Our findings indicate that median nerve electrical stimulation induced an up-regulation of orexin-A and OX1R expression in the prefrontal cortex of traumatic brain injury-induced coma rats, which may be a potential mechanism involved in the wake-promoting effects of median nerve electrical stimulation.
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Affiliation(s)
- Zhen Feng
- Department of Rehabilitation Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Ying-Jun Zhong
- Department of Rehabilitation Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Liang Wang
- Department of Rehabilitation Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Tian-Qi Wei
- Department of Rehabilitation Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
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13
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Evans JA, Suen TC, Callif BL, Mitchell AS, Castanon-Cervantes O, Baker KM, Kloehn I, Baba K, Teubner BJW, Ehlen JC, Paul KN, Bartness TJ, Tosini G, Leise T, Davidson AJ. Shell neurons of the master circadian clock coordinate the phase of tissue clocks throughout the brain and body. BMC Biol 2015; 13:43. [PMID: 26099272 PMCID: PMC4489020 DOI: 10.1186/s12915-015-0157-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 06/16/2015] [Indexed: 11/18/2022] Open
Abstract
Background Daily rhythms in mammals are programmed by a master clock in the suprachiasmatic nucleus (SCN). The SCN contains two main compartments (shell and core), but the role of each region in system-level coordination remains ill defined. Herein, we use a functional assay to investigate how downstream tissues interpret region-specific outputs by using in vivo exposure to long day photoperiods to temporally dissociate the SCN. We then analyze resulting changes in the rhythms of clocks located throughout the brain and body to examine whether they maintain phase synchrony with the SCN shell or core. Results Nearly all of the 17 tissues examined in the brain and body maintain phase synchrony with the SCN shell, but not the SCN core, which indicates that downstream oscillators are set by cues controlled specifically by the SCN shell. Interestingly, we also found that SCN dissociation diminished the amplitude of rhythms in core clock gene and protein expression in brain tissues by 50–75 %, which suggests that light-driven changes in the functional organization of the SCN markedly influence the strength of rhythms in downstream tissues. Conclusions Overall, our results reveal that body clocks receive time-of-day cues specifically from the SCN shell, which may be an adaptive design principle that serves to maintain system-level phase relationships in a changing environment. Further, we demonstrate that lighting conditions alter the amplitude of the molecular clock in downstream tissues, which uncovers a new form of plasticity that may contribute to seasonal changes in physiology and behavior. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0157-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jennifer A Evans
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53233, USA.
| | - Ting-Chung Suen
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Ben L Callif
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53233, USA
| | - Andrew S Mitchell
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | | | - Kimberly M Baker
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53233, USA
| | - Ian Kloehn
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, 53233, USA
| | - Kenkichi Baba
- Department of Pharmacology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Brett J W Teubner
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA, 30302, USA.,Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - J Christopher Ehlen
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Ketema N Paul
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Timothy J Bartness
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA, 30302, USA
| | - Gianluca Tosini
- Department of Pharmacology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Tanya Leise
- Department of Mathematics and Statistics, Amherst College, Amherst, MA, 01002, USA
| | - Alec J Davidson
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, 30310, USA
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14
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ZHONG YINGJUN, FENG ZHEN, WANG LIANG, WEI TIANQI. Wake-promoting actions of median nerve stimulation in TBI-induced coma: An investigation of orexin-A and orexin receptor 1 in the hypothalamic region. Mol Med Rep 2015; 12:4441-4447. [DOI: 10.3892/mmr.2015.3898] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 05/08/2015] [Indexed: 11/06/2022] Open
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Silver R, Kriegsfeld LJ. Circadian rhythms have broad implications for understanding brain and behavior. Eur J Neurosci 2014; 39:1866-80. [PMID: 24799154 DOI: 10.1111/ejn.12593] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 03/14/2014] [Accepted: 03/19/2014] [Indexed: 12/28/2022]
Abstract
Circadian rhythms are generated by an endogenously organized timing system that drives daily rhythms in behavior, physiology and metabolism. In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus is the locus of a master circadian clock. The SCN is synchronized to environmental changes in the light:dark cycle by direct, monosynaptic innervation via the retino-hypothalamic tract. In turn, the SCN coordinates the rhythmic activities of innumerable subordinate clocks in virtually all bodily tissues and organs. The core molecular clockwork is composed of a transcriptional/post-translational feedback loop in which clock genes and their protein products periodically suppress their own transcription. This primary loop connects to downstream output genes by additional, interlocked transcriptional feedback loops to create tissue-specific 'circadian transcriptomes'. Signals from peripheral tissues inform the SCN of the internal state of the organism and the brain's master clock is modified accordingly. A consequence of this hierarchical, multilevel feedback system is that there are ubiquitous effects of circadian timing on genetic and metabolic responses throughout the body. This overview examines landmark studies in the history of the study of circadian timing system, and highlights our current understanding of the operation of circadian clocks with a focus on topics of interest to the neuroscience community.
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Affiliation(s)
- Rae Silver
- Department of Psychology, Barnard College, Columbia University, New York, NY, USA; Department of Psychology, Columbia University, Mail Code 5501, 1190 Amsterdam Avenue, New York, NY, 10027, USA; Department of Pathology and Cell Biology, Columbia University Health Sciences, New York, NY, USA
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Evans JA, Leise TL, Castanon-Cervantes O, Davidson AJ. Dynamic interactions mediated by nonredundant signaling mechanisms couple circadian clock neurons. Neuron 2014; 80:973-83. [PMID: 24267653 DOI: 10.1016/j.neuron.2013.08.022] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2013] [Indexed: 11/24/2022]
Abstract
Interactions among suprachiasmatic nucleus (SCN) neurons are required for robust circadian rhythms entrained to local time. To investigate these signaling mechanisms, we developed a functional coupling assay that uniquely captures the dynamic process by which SCN neurons interact. As a population, SCN neurons typically display synchronized rhythms with similar peak times, but will peak 6-12 hr apart after in vivo exposure to long days. Once they are removed from these conditions, SCN neurons resynchronize through a phase-dependent coupling process mediated by both vasoactive intestinal polypeptide (VIP) and GABAA signaling. Notably, GABAA signaling contributes to coupling when the SCN network is in an antiphase configuration, but opposes synchrony under steady-state conditions. Further, VIP acts together with GABAA signaling to couple the network in an antiphase configuration, but promotes synchrony under steady-state conditions by counteracting the actions of GABAA signaling. Thus, SCN neurons interact through nonredundant coupling mechanisms influenced by the state of the network.
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Affiliation(s)
- Jennifer A Evans
- Department of Neurobiology, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310, USA
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17
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Mahoney CE, McKinley Brewer J, Bittman EL. Central control of circadian phase in arousal-promoting neurons. PLoS One 2013; 8:e67173. [PMID: 23826226 PMCID: PMC3691112 DOI: 10.1371/journal.pone.0067173] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 05/14/2013] [Indexed: 11/18/2022] Open
Abstract
Cells of the dorsomedial/lateral hypothalamus (DMH/LH) that produce hypocretin (HCRT) promote arousal in part by activation of cells of the locus coeruleus (LC) which express tyrosine hydroxylase (TH). The suprachiasmatic nucleus (SCN) drives endogenous daily rhythms, including those of sleep and wakefulness. These circadian oscillations are generated by a transcriptional-translational feedback loop in which the Period (Per) genes constitute critical components. This cell-autonomous molecular clock operates not only within the SCN but also in neurons of other brain regions. However, the phenotype of such neurons and the nature of the phase controlling signal from the pacemaker are largely unknown. We used dual fluorescent in situ hybridization to assess clock function in vasopressin, HCRT and TH cells of the SCN, DMH/LH and LC, respectively, of male Syrian hamsters. In the first experiment, we found that Per1 expression in HCRT and TH oscillated in animals held in constant darkness with a peak phase that lagged that in AVP cells of the SCN by several hours. In the second experiment, hamsters induced to split their locomotor rhythms by exposure to constant light had asymmetric Per1 expression within cells of the middle SCN at 6 h before activity onset (AO) and in HCRT cells 9 h before and at AO. We did not observe evidence of lateralization of Per1 expression in the LC. We conclude that the SCN communicates circadian phase to HCRT cells via lateralized neural projections, and suggests that Per1 expression in the LC may be regulated by signals of a global or bilateral nature.
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Affiliation(s)
- Carrie E. Mahoney
- Neuroscience and Behavior Program, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Judy McKinley Brewer
- Neuroscience and Behavior Program, University of Massachusetts, Amherst, Massachusetts, United States of America
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Eric L. Bittman
- Neuroscience and Behavior Program, University of Massachusetts, Amherst, Massachusetts, United States of America
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
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18
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Michel S, Marek R, vanderLeest HT, vanSteensel MJ, Schwartz WJ, Colwell CS, Meijer JH. Mechanism of bilateral communication in the suprachiasmatic nucleus. Eur J Neurosci 2013; 37:964-71. [DOI: 10.1111/ejn.12109] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/17/2012] [Accepted: 11/26/2012] [Indexed: 01/01/2023]
Affiliation(s)
- Stephan Michel
- Laboratory for Neurophysiology; Department of Molecular Cell Biology; Leiden University Medical Center; LUMC PZ S5-P; PO 9600; 2300 RC; Leiden; The Netherlands
| | - Roger Marek
- The Queensland Brain Institute; University of Queensland; St Lucia; Qld; Australia
| | - Henk T. vanderLeest
- Laboratory for Neurophysiology; Department of Molecular Cell Biology; Leiden University Medical Center; LUMC PZ S5-P; PO 9600; 2300 RC; Leiden; The Netherlands
| | | | - William J. Schwartz
- Department of Neurology; University of Massachusetts Medical School; Worcester; MA; USA
| | | | - Johanna H. Meijer
- Laboratory for Neurophysiology; Department of Molecular Cell Biology; Leiden University Medical Center; LUMC PZ S5-P; PO 9600; 2300 RC; Leiden; The Netherlands
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