1
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Amedzrovi Agbesi RJ, El Merhie A, Spencer NJ, Hibberd T, Chevalier NR. Tetrodotoxin-resistant mechanosensitivity and L-type calcium channel-mediated spontaneous calcium activity in enteric neurons. Exp Physiol 2024; 109:1545-1556. [PMID: 38979869 PMCID: PMC11363105 DOI: 10.1113/ep091977] [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: 05/13/2024] [Accepted: 06/20/2024] [Indexed: 07/10/2024]
Abstract
Gut motility undergoes a switch from myogenic to neurogenic control in late embryonic development. Here, we report on the electrical events that underlie this transition in the enteric nervous system, using the GCaMP6f reporter in neural crest cell derivatives. We found that spontaneous calcium activity is tetrodotoxin (TTX) resistant at stage E11.5, but not at E18.5. Motility at E18.5 was characterized by periodic, alternating high- and low-frequency contractions of the circular smooth muscle; this frequency modulation was inhibited by TTX. Calcium imaging at the neurogenic-motility stages E18.5-P3 showed that CaV1.2-positive neurons exhibited spontaneous calcium activity, which was inhibited by nicardipine and 2-aminoethoxydiphenyl borate (2-APB). Our protocol locally prevented muscle tone relaxation, arguing for a direct effect of nicardipine on enteric neurons, rather than indirectly by its relaxing effect on muscle. We demonstrated that the ENS was mechanosensitive from early stages on (E14.5) and that this behaviour was TTX and 2-APB resistant. We extended our results on L-type channel-dependent spontaneous activity and TTX-resistant mechanosensitivity to the adult colon. Our results shed light on the critical transition from myogenic to neurogenic motility in the developing gut, as well as on the intriguing pathways mediating electro-mechanical sensitivity in the enteric nervous system. HIGHLIGHTS: What is the central question of this study? What are the first neural electric events underlying the transition from myogenic to neurogenic motility in the developing gut, what channels do they depend on, and does the enteric nervous system already exhibit mechanosensitivity? What is the main finding and its importance? ENS calcium activity is sensitive to tetrodotoxin at stage E18.5 but not E11.5. Spontaneous electric activity at fetal and adult stages is crucially dependent on L-type calcium channels and IP3R receptors, and the enteric nervous system exhibits a tetrodotoxin-resistant mechanosensitive response. Abstract figure legend Tetrodotoxin-resistant Ca2+ rise induced by mechanical stimulation in the E18.5 mouse duodenum.
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Affiliation(s)
| | - Amira El Merhie
- Laboratoire Matière et Systèmes Complexes UMR 7057Université Paris Cité/CNRSParisFrance
| | - Nick J. Spencer
- College of Medicine and Public HealthFlinders UniversityAdelaideSouth AustraliaAustralia
| | - Tim Hibberd
- College of Medicine and Public HealthFlinders UniversityAdelaideSouth AustraliaAustralia
| | - Nicolas R. Chevalier
- Laboratoire Matière et Systèmes Complexes UMR 7057Université Paris Cité/CNRSParisFrance
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2
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Hunt JE, Pratt KG, Molnár Z. Ocular Necessities: A Neuroethological Perspective on Vertebrate Visual Development. BRAIN, BEHAVIOR AND EVOLUTION 2024; 99:96-108. [PMID: 38447544 PMCID: PMC11152017 DOI: 10.1159/000536035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 12/24/2023] [Indexed: 03/08/2024]
Abstract
BACKGROUND By examining species-specific innate behaviours, neuroethologists have characterized unique neural strategies and specializations from throughout the animal kingdom. Simultaneously, the field of evolutionary developmental biology (informally, "evo-devo") seeks to make inferences about animals' evolutionary histories through careful comparison of developmental processes between species, because evolution is the evolution of development. Yet despite the shared focus on cross-species comparisons, there is surprisingly little crosstalk between these two fields. Insights can be gleaned at the intersection of neuroethology and evo-devo. Every animal develops within an environment, wherein ecological pressures advantage some behaviours and disadvantage others. These pressures are reflected in the neurodevelopmental strategies employed by different animals across taxa. SUMMARY Vision is a system of particular interest for studying the adaptation of animals to their environments. The visual system enables a wide variety of animals across the vertebrate lineage to interact with their environments, presenting a fantastic opportunity to examine how ecological pressures have shaped animals' behaviours and developmental strategies. Applying a neuroethological lens to the study of visual development, we advance a novel theory that accounts for the evolution of spontaneous retinal waves, an important phenomenon in the development of the visual system, across the vertebrate lineage. KEY MESSAGES We synthesize literature on spontaneous retinal waves from across the vertebrate lineage. We find that ethological considerations explain some cross-species differences in the dynamics of retinal waves. In zebrafish, retinal waves may be more important for the development of the retina itself, rather than the retinofugal projections. We additionally suggest empirical tests to determine whether Xenopus laevis experiences retinal waves.
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Affiliation(s)
- Jasper Elan Hunt
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Kara Geo Pratt
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
- Program in Neuroscience, University of Wyoming, Laramie, WY, USA
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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3
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Laurent G. Mysterious ultraslow and ordered activity observed in the cortex. Nature 2024; 625:244-245. [PMID: 38123849 DOI: 10.1038/d41586-023-03795-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
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4
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Abstract
The nervous system regulates tissue stem and precursor populations throughout life. Parallel to roles in development, the nervous system is emerging as a critical regulator of cancer, from oncogenesis to malignant growth and metastatic spread. Various preclinical models in a range of malignancies have demonstrated that nervous system activity can control cancer initiation and powerfully influence cancer progression and metastasis. Just as the nervous system can regulate cancer progression, cancer also remodels and hijacks nervous system structure and function. Interactions between the nervous system and cancer occur both in the local tumour microenvironment and systemically. Neurons and glial cells communicate directly with malignant cells in the tumour microenvironment through paracrine factors and, in some cases, through neuron-to-cancer cell synapses. Additionally, indirect interactions occur at a distance through circulating signals and through influences on immune cell trafficking and function. Such cross-talk among the nervous system, immune system and cancer-both systemically and in the local tumour microenvironment-regulates pro-tumour inflammation and anti-cancer immunity. Elucidating the neuroscience of cancer, which calls for interdisciplinary collaboration among the fields of neuroscience, developmental biology, immunology and cancer biology, may advance effective therapies for many of the most difficult to treat malignancies.
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Affiliation(s)
- Rebecca Mancusi
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
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5
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Tarchick MJ, Clute DA, Renna JM. Modeling cholinergic retinal waves: starburst amacrine cells shape wave generation, propagation, and direction bias. Sci Rep 2023; 13:2834. [PMID: 36808155 PMCID: PMC9938278 DOI: 10.1038/s41598-023-29572-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 02/07/2023] [Indexed: 02/19/2023] Open
Abstract
Stage II cholinergic retinal waves are one of the first instances of neural activity in the visual system as they are present at a developmental timepoint in which light-evoked activity remains largely undetectable. These waves of spontaneous neural activity sweeping across the developing retina are generated by starburst amacrine cells, depolarize retinal ganglion cells, and drive the refinement of retinofugal projections to numerous visual centers in the brain. Building from several well-established models, we assemble a spatial computational model of starburst amacrine cell-mediated wave generation and wave propagation that includes three significant advancements. First, we model the intrinsic spontaneous bursting of the starburst amacrine cells, including the slow afterhyperpolarization, which shapes the stochastic process of wave generation. Second, we establish a mechanism of wave propagation using reciprocal acetylcholine release, synchronizing the bursting activity of neighboring starburst amacrine cells. Third, we model the additional starburst amacrine cell release of GABA, changing the spatial propagation of retinal waves and in certain instances, the directional bias of the retinal wave front. In total, these advancements comprise a now more comprehensive model of wave generation, propagation, and direction bias.
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Affiliation(s)
| | - Dustin A Clute
- Department of Biology, University of Akron, Akron, OH, 44325-3908, USA
| | - Jordan M Renna
- Department of Biology, University of Akron, Akron, OH, 44325-3908, USA.
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6
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Guo C, Wang A, Cheng H, Chen L. New imaging instrument in animal models: Two-photon miniature microscope and large field of view miniature microscope for freely behaving animals. J Neurochem 2023; 164:270-283. [PMID: 36281555 DOI: 10.1111/jnc.15711] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 09/19/2022] [Accepted: 10/12/2022] [Indexed: 11/30/2022]
Abstract
Over the past decade, novel optical imaging tools have been developed for imaging neuronal activities along with the evolution of fluorescence indicators with brighter expression and higher sensitivity. Miniature microscopes, as revolutionary approaches, enable the imaging of large populations of neuron ensembles in freely behaving rodents and mammals, which allows exploring the neural basis of behaviors. Recent progress in two-photon miniature microscopes and mesoscale single-photon miniature microscopes further expand those affordable methods to navigate neural activities during naturalistic behaviors. In this review article, two-photon miniature microscopy techniques are summarized historically from the first documented attempt to the latest ones, and comparisons are made. The driving force behind and their potential for neuroscientific inquiries are also discussed. Current progress in terms of the mesoscale, i.e., the large field-of-view miniature microscopy technique, is addressed as well. Then, pipelines for registering single cells from the data of two-photon and large field-of-view miniature microscopes are discussed. Finally, we present the potential evolution of the techniques.
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Affiliation(s)
- Changliang Guo
- Beijing Institute of Collaborative Innovation, Beijing, China.,State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China
| | - Aimin Wang
- School of Electronics, Peking University, Beijing, China.,State Key Laboratory of Advanced Optical Communication System and Networks, Peking University, Beijing, China
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China.,Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing, China
| | - Liangyi Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China.,PKU-IDG/McGovern Institute for Brain Research, Beijing, China.,Beijing Academy of Artificial Intelligence, Beijing, China
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7
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Konecny L, Quadir R, Ninan A, Rodríguez-Contreras A. Neurovascular responses to neuronal activity during sensory development. Front Cell Neurosci 2022; 16:1025429. [DOI: 10.3389/fncel.2022.1025429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/26/2022] [Indexed: 11/13/2022] Open
Abstract
Understanding the development of intercellular communication in sensory regions is relevant to elucidate mechanisms of physiological and pathological responses to oxygen shortage in the newborn brain. Decades of studies in laboratory rodents show that neuronal activity impacts sensory maturation during two periods of postnatal development distinguished by the maturation of accessory structures at the sensory periphery. During the first of these developmental periods, angiogenesis is modulated by neuronal activity, and physiological levels of neuronal activity cause local tissue hypoxic events. This correlation suggests that neuronal activity is upstream of the production of angiogenic factors, a process that is mediated by intermittent hypoxia caused by neuronal oxygen consumption. In this perspective article we address three theoretical implications based on this hypothesis: first, that spontaneous activity of sensory neurons has properties that favor the generation of intermittent tissue hypoxia in neonate rodents; second, that intermittent hypoxia promotes the expression of hypoxia inducible transcription factors (HIFs) in sensory neurons and astrocytes; and third, that activity-dependent production of angiogenic factors is involved in pathological oxygen contexts.
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8
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Banerjee P, Kubo F, Nakaoka H, Ajima R, Sato T, Hirata T, Iwasato T. Spontaneous activity in whisker-innervating region of neonatal mouse trigeminal ganglion. Sci Rep 2022; 12:16311. [PMID: 36175429 PMCID: PMC9522796 DOI: 10.1038/s41598-022-20068-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/08/2022] [Indexed: 11/17/2022] Open
Abstract
Spontaneous activity during the early postnatal period is thought to be crucial for the establishment of mature neural circuits. It remains unclear if the peripheral structure of the developing somatosensory system exhibits spontaneous activity, similar to that observed in the retina and cochlea of developing mammals. By establishing an ex vivo calcium imaging system, here we found that neurons in the whisker-innervating region of the trigeminal ganglion (TG) of neonatal mice generate spontaneous activity. A small percentage of neurons showed some obvious correlated activity, and these neurons were mostly located close to one another. TG spontaneous activity was majorly exhibited by medium-to-large diameter neurons, a characteristic of mechanosensory neurons, and was blocked by chelation of extracellular calcium. Moreover, this activity was diminished by the adult stage. Spontaneous activity in the TG during the first postnatal week could be a source of spontaneous activity observed in the neonatal mouse barrel cortex.
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Affiliation(s)
- Piu Banerjee
- Laboratory of Mammalian Neural Circuits, National Institute of Genetics (NIG), Mishima, Japan.,Department of Genetics, SOKENDAI, Mishima, Japan
| | - Fumi Kubo
- Department of Genetics, SOKENDAI, Mishima, Japan.,Laboratory of Systems Neuroscience, NIG, Mishima, Japan
| | - Hirofumi Nakaoka
- Department of Cancer Genome Research, Sasaki Institute, Tokyo, Japan
| | - Rieko Ajima
- Department of Genetics, SOKENDAI, Mishima, Japan.,Laboratory of Mammalian Development, NIG, Mishima, Japan
| | - Takuya Sato
- Laboratory of Mammalian Neural Circuits, National Institute of Genetics (NIG), Mishima, Japan
| | - Tatsumi Hirata
- Department of Genetics, SOKENDAI, Mishima, Japan.,Laboratory of Brain Function, NIG, Mishima, Japan
| | - Takuji Iwasato
- Laboratory of Mammalian Neural Circuits, National Institute of Genetics (NIG), Mishima, Japan. .,Department of Genetics, SOKENDAI, Mishima, Japan.
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9
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Ma S, Wu T, Chen X, Wang Y, Ma J, Chen H, Riaud A, Wan J, Xu Z, Chen L, Ren J, Zhang DW, Zhou P, Chai Y, Bao W. A 619-pixel machine vision enhancement chip based on two-dimensional semiconductors. SCIENCE ADVANCES 2022; 8:eabn9328. [PMID: 35921422 PMCID: PMC9348785 DOI: 10.1126/sciadv.abn9328] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 06/21/2022] [Indexed: 06/09/2023]
Abstract
The rapid development of machine vision applications demands hardware that can sense and process visual information in a single monolithic unit to avoid redundant data transfer. Here, we design and demonstrate a monolithic vision enhancement chip with light-sensing, memory, digital-to-analog conversion, and processing functions by implementing a 619-pixel with 8582 transistors and physical dimensions of 10 mm by 10 mm based on a wafer-scale two-dimensional (2D) monolayer molybdenum disulfide (MoS2). The light-sensing function with analog MoS2 transistor circuits offers low noise and high photosensitivity. Furthermore, we adopt a MoS2 analog processing circuit to dynamically adjust the photocurrent of individual imaging sensor, which yields a high dynamic light-sensing range greater than 90 decibels. The vision chip allows the applications for contrast enhancement and noise reduction of image processing. This large-scale monolithic chip based on 2D semiconductors shows multiple functions with light sensing, memory, and processing for artificial machine vision applications, exhibiting the potentials of 2D semiconductors for future electronics.
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Affiliation(s)
- Shunli Ma
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Tianxiang Wu
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Xinyu Chen
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Yin Wang
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Jingyi Ma
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Honglei Chen
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Antoine Riaud
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Jing Wan
- State Key Laboratory of ASIC and System, School of Information Science and Technology, Fudan University, Shanghai 200433, China
| | - Zihan Xu
- Shenzhen Sixcarbon Technology, 188 Jiangshi Road, Shenzhen 518106, China
| | - Lin Chen
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Junyan Ren
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - David Wei Zhang
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Peng Zhou
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Yang Chai
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Wenzhong Bao
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
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10
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Abstract
Nervous system activity regulates development, homeostasis, and plasticity of the brain as well as other organs in the body. These mechanisms are subverted in cancer to propel malignant growth. In turn, cancers modulate neural structure and function to augment growth-promoting neural signaling in the tumor microenvironment. Approaching cancer biology from a neuroscience perspective will elucidate new therapeutic strategies for presently lethal forms of cancer. In this review, we highlight the neural signaling mechanisms recapitulated in primary brain tumors, brain metastases, and solid tumors throughout the body that regulate cancer progression. Expected final online publication date for the Annual Review of Neuroscience, Volume 45 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Michael B Keough
- Department of Neurology and Neurological Sciences and Howard Hughes Medical Institute, Stanford University, Stanford, California, USA;
| | - Michelle Monje
- Department of Neurology and Neurological Sciences and Howard Hughes Medical Institute, Stanford University, Stanford, California, USA;
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11
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Behpour S, Field DJ, Albert MV. On the Role of LGN/V1 Spontaneous Activity as an Innate Learning Pattern for Visual Development. Front Physiol 2021; 12:695431. [PMID: 34776991 PMCID: PMC8589027 DOI: 10.3389/fphys.2021.695431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 10/05/2021] [Indexed: 11/16/2022] Open
Abstract
Correlated, spontaneous neural activity is known to play a necessary role in visual development, but the higher-order statistical structure of these coherent, amorphous patterns has only begun to emerge in the past decade. Several computational studies have demonstrated how this endogenous activity can be used to train a developing visual system. Models that generate spontaneous activity analogous to retinal waves have shown that these waves can serve as stimuli for efficient coding models of V1. This general strategy in development has one clear advantage: The same learning algorithm can be used both before and after eye-opening. This same insight can be applied to understanding LGN/V1 spontaneous activity. Although lateral geniculate nucleus (LGN) activity has been less discussed in the literature than retinal waves, here we argue that the waves found in the LGN have a number of properties that fill the role of a training pattern. We make the case that the role of “innate learning” with spontaneous activity is not only possible, but likely in later stages of visual development, and worth pursuing further using an efficient coding paradigm.
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Affiliation(s)
- Sahar Behpour
- Department of Information Science, University of North Texas, Denton, TX, United States
| | - David J Field
- Department of Psychology, Cornell University, Ithaca, NY, United States
| | - Mark V Albert
- Department of Computer Science and Engineering, University of North Texas, Denton, TX, United States.,Department of Biomedical Engineering, University of North Texas, Denton, TX, United States
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12
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Talukdar S, Emdad L, Das SK, Fisher PB. GAP junctions: multifaceted regulators of neuronal differentiation. Tissue Barriers 2021; 10:1982349. [PMID: 34651545 DOI: 10.1080/21688370.2021.1982349] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Gap junctions are intercellular membrane channels consisting of connexin proteins, which contribute to direct cytoplasmic exchange of small molecules, substrates and metabolites between adjacent cells. These channels play important roles in neuronal differentiation, maintenance, survival and function. Gap junctions regulate differentiation of neurons from embryonic, neural and induced pluripotent stem cells. In addition, they control transdifferentiation of neurons from mesenchymal stem cells. The expression and levels of several connexins correlate with cell cycle changes and different stages of neurogenesis. Connexins such as Cx36, Cx45, and Cx26, play a crucial role in neuronal function. Several connexin knockout mice display lethal or severely impaired phenotypes. Aberrations in connexin expression is frequently associated with various neurodegenerative disorders. Gap junctions also act as promising therapeutic targets for neuronal regenerative medicine, because of their role in neural stem cell integration, injury and remyelination.
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Affiliation(s)
- Sarmistha Talukdar
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States
| | - Luni Emdad
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States.,Vcu Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Swadesh K Das
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States.,Vcu Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States.,Vcu Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
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13
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Parmigiani E, Scalera M, Mori E, Tantillo E, Vannini E. Old Stars and New Players in the Brain Tumor Microenvironment. Front Cell Neurosci 2021; 15:709917. [PMID: 34690699 PMCID: PMC8527006 DOI: 10.3389/fncel.2021.709917] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/04/2021] [Indexed: 12/12/2022] Open
Abstract
In recent years, the direct interaction between cancer cells and tumor microenvironment (TME) has emerged as a crucial regulator of tumor growth and a promising therapeutic target. The TME, including the surrounding peritumoral regions, is dynamically modified during tumor progression and in response to therapies. However, the mechanisms regulating the crosstalk between malignant and non-malignant cells are still poorly understood, especially in the case of glioma, an aggressive form of brain tumor. The presence of unique brain-resident cell types, namely neurons and glial cells, and an exceptionally immunosuppressive microenvironment pose additional important challenges to the development of effective treatments targeting the TME. In this review, we provide an overview on the direct and indirect interplay between glioma and neuronal and glial cells, introducing new players and mechanisms that still deserve further investigation. We will focus on the effects of neural activity and glial response in controlling glioma cell behavior and discuss the potential of exploiting these cellular interactions to develop new therapeutic approaches with the aim to preserve proper brain functionality.
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Affiliation(s)
- Elena Parmigiani
- Embryology and Stem Cell Biology, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Marta Scalera
- Neuroscience Institute, Consiglio Nazionale delle Ricerche (CNR), Pisa, Italy
| | | | - Elena Tantillo
- Neuroscience Institute, Consiglio Nazionale delle Ricerche (CNR), Pisa, Italy
| | - Eleonora Vannini
- Neuroscience Institute, Consiglio Nazionale delle Ricerche (CNR), Pisa, Italy
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14
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Nakazawa S, Iwasato T. Spatial organization and transitions of spontaneous neuronal activities in the developing sensory cortex. Dev Growth Differ 2021; 63:323-339. [PMID: 34166527 DOI: 10.1111/dgd.12739] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 12/30/2022]
Abstract
The sensory cortex underlies our ability to perceive and interact with the external world. Sensory perceptions are controlled by specialized neuronal circuits established through fine-tuning, which relies largely on neuronal activity during the development. Spontaneous neuronal activity is an essential driving force of neuronal circuit refinement. At early developmental stages, sensory cortices display spontaneous activities originating from the periphery and characterized by correlated firing arranged spatially according to the modality. The firing patterns are reorganized over time and become sparse, which is typical for the mature brain. This review focuses mainly on rodent sensory cortices. First, the features of the spontaneous activities during early postnatal stages are described. Then, the developmental changes in the spatial organization of the spontaneous activities and the transition mechanisms involved are discussed. The identification of the principles controlling the spatial organization of spontaneous activities in the developing sensory cortex is essential to understand the self-organization process of neuronal circuits.
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Affiliation(s)
- Shingo Nakazawa
- Laboratory of Mammalian Neural Circuits, National Institute of Genetics, Mishima, Japan.,Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | - Takuji Iwasato
- Laboratory of Mammalian Neural Circuits, National Institute of Genetics, Mishima, Japan.,Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima, Japan
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15
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Choi BJ, Chen YCD, Desplan C. Building a circuit through correlated spontaneous neuronal activity in the developing vertebrate and invertebrate visual systems. Genes Dev 2021; 35:677-691. [PMID: 33888564 PMCID: PMC8091978 DOI: 10.1101/gad.348241.121] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
During the development of the vertebrate nervous systems, genetic programs assemble an immature circuit that is subsequently refined by neuronal activity evoked by external stimuli. However, prior to sensory experience, the intrinsic property of the developing nervous system also triggers correlated network-level neuronal activity, with retinal waves in the developing vertebrate retina being the best documented example. Spontaneous activity has also been found in the visual system of Drosophila Here, we compare the spontaneous activity of the developing visual system between mammalian and Drosophila and suggest that Drosophila is an emerging model for mechanistic and functional studies of correlated spontaneous activity.
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Affiliation(s)
- Ben Jiwon Choi
- Department of Biology, New York University, New York, New York 10003, USA
| | | | - Claude Desplan
- Department of Biology, New York University, New York, New York 10003, USA
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16
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NMDA Receptor Enhances Correlation of Spontaneous Activity in Neonatal Barrel Cortex. J Neurosci 2021; 41:1207-1217. [PMID: 33372060 DOI: 10.1523/jneurosci.0527-20.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 12/09/2020] [Accepted: 12/14/2020] [Indexed: 01/07/2023] Open
Abstract
Correlated spontaneous activity plays critical role in the organization of neocortical circuits during development. However, cortical mechanisms regulating activity correlation are still elusive. In this study, using two-photon calcium imaging of the barrel cortex layer 4 (L4) in living neonatal mice, we found that NMDA receptors (NMDARs) in L4 neurons are important for enhancement of spontaneous activity correlation. Disruption of GluN1 (Grin1), an obligatory NMDAR subunit, in a sparse population of L4 neurons reduced activity correlation between GluN1 knock-out (GluN1KO) neuron pairs within a barrel. This reduction in activity correlation was even detected in L4 neuron pairs in neighboring barrels and most evident when either or both of neurons are located on the barrel edge. Our results provide evidence for the involvement of L4 neuron NMDARs in spatial organization of the spontaneous firing activity of L4 neurons in the neonatal barrel cortex.SIGNIFICANCE STATEMENT Precise wiring of the thalamocortical circuits is necessary for proper sensory information processing, and thalamus-derived correlated spontaneous activity is important for thalamocortical circuit formation. The molecular mechanisms involved in the correlated activity transfer from the thalamus to the neocortex are largely unknown. In vivo two-photon calcium imaging of the neonatal barrel cortex revealed that correlated spontaneous activity between layer four neurons is reduced by mosaic knock-out (KO) of the NMDA receptor (NMDAR) obligatory subunit GluN1. Our results suggest that the function of NMDARs in layer four neurons is necessary for the communication between presynaptic and postsynaptic partners during thalamocortical circuit formation.
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17
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Rao MS, Mizuno H. Elucidating mechanisms of neuronal circuit formation in layer 4 of the somatosensory cortex via intravital imaging. Neurosci Res 2020; 167:47-53. [PMID: 33309867 DOI: 10.1016/j.neures.2020.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/27/2020] [Accepted: 10/01/2020] [Indexed: 12/13/2022]
Abstract
The cerebral cortex has complex yet perfectly wired neuronal circuits that are important for high-level brain functions such as perception and cognition. The rodent's somatosensory system is widely used for understanding the mechanisms of circuit formation during early developmental periods. In this review, we summarize the developmental processes of circuit formation in layer 4 of the somatosensory cortex, and we describe the molecules involved in layer 4 circuit formation and neuronal activity-dependent mechanisms of circuit formation. We also introduce the dynamic mechanisms of circuit formation in layer 4 revealed by intravital two-photon imaging technologies, which include time-lapse imaging of neuronal morphology and calcium imaging of neuronal activity in newborn mice.
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Affiliation(s)
- Madhura S Rao
- Laboratory of Multi-dimensional Imaging, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, 860-0811, Japan; Graduate School of Medical Sciences, Kumamoto University, Kumamoto, 860-0811, Japan
| | - Hidenobu Mizuno
- Laboratory of Multi-dimensional Imaging, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, 860-0811, Japan; Graduate School of Medical Sciences, Kumamoto University, Kumamoto, 860-0811, Japan.
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18
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Cellular identity and Ca 2+ signaling activity of the non-reproductive GnRH system in the Ciona intestinalis type A (Ciona robusta) larva. Sci Rep 2020; 10:18590. [PMID: 33122709 PMCID: PMC7596717 DOI: 10.1038/s41598-020-75344-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 10/12/2020] [Indexed: 12/14/2022] Open
Abstract
Tunicate larvae have a non-reproductive gonadotropin-releasing hormone (GnRH) system with multiple ligands and receptor heterodimerization enabling complex regulation. In Ciona intestinalis type A larvae, one of the gnrh genes, gnrh2, is conspicuously expressed in the motor ganglion and nerve cord, which are homologous structures to the hindbrain and spinal cord, respectively, of vertebrates. The gnrh2 gene is also expressed in the proto-placodal sensory neurons, which are the proposed homologue of vertebrate olfactory neurons. Tunicate larvae occupy a non-reproductive dispersal stage, yet the role of their GnRH system remains elusive. In this study, we investigated neuronal types of gnrh2-expressing cells in Ciona larvae and visualized the activity of these cells by fluorescence imaging using a calcium sensor protein. Some cholinergic neurons and dopaminergic cells express gnrh2, suggesting that GnRH plays a role in controlling swimming behavior. However, none of the gnrh2-expressing cells overlap with glycinergic or GABAergic neurons. A role in motor control is also suggested by a relationship between the activity of gnrh2-expressing cells and tail movements. Interestingly, gnrh2-positive ependymal cells in the nerve cord, known as a kind of glia cells, actively produced Ca2+ transients, suggesting that active intercellular signaling occurs in the glia cells of the nerve cord.
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19
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Saternos H, Ley S, AbouAlaiwi W. Primary Cilia and Calcium Signaling Interactions. Int J Mol Sci 2020; 21:E7109. [PMID: 32993148 PMCID: PMC7583801 DOI: 10.3390/ijms21197109] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
The calcium ion (Ca2+) is a diverse secondary messenger with a near-ubiquitous role in a vast array of cellular processes. Cilia are present on nearly every cell type in either a motile or non-motile form; motile cilia generate fluid flow needed for a variety of biological processes, such as left-right body patterning during development, while non-motile cilia serve as the signaling powerhouses of the cell, with vital singling receptors localized to their ciliary membranes. Much of the research currently available on Ca2+-dependent cellular actions and primary cilia are tissue-specific processes. However, basic stimuli-sensing pathways, such as mechanosensation, chemosensation, and electrical sensation (electrosensation), are complex processes entangled in many intersecting pathways; an overview of proposed functions involving cilia and Ca2+ interplay will be briefly summarized here. Next, we will focus on summarizing the evidence for their interactions in basic cellular activities, including the cell cycle, cell polarity and migration, neuronal pattering, glucose-mediated insulin secretion, biliary regulation, and bone formation. Literature investigating the role of cilia and Ca2+-dependent processes at a single-cellular level appears to be scarce, though overlapping signaling pathways imply that cilia and Ca2+ interact with each other on this level in widespread and varied ways on a perpetual basis. Vastly different cellular functions across many different cell types depend on context-specific Ca2+ and cilia interactions to trigger the correct physiological responses, and abnormalities in these interactions, whether at the tissue or the single-cell level, can result in diseases known as ciliopathies; due to their clinical relevance, pathological alterations of cilia function and Ca2+ signaling will also be briefly touched upon throughout this review.
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Affiliation(s)
| | | | - Wissam AbouAlaiwi
- Department of Pharmacology and Experimental Therapeutics, University of Toledo Health Science Campus, Toledo, OH 43614, USA; (H.S.); (S.L.)
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20
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Bachmann G, Frohns F, Thangaraj G, Bausch A, Layer PG. IPL Sublamination in Chicken Retinal Spheroids Is Initiated via Müller Cells and Cholinergic Differentiation, and Is Disrupted by NMDA Signaling. Invest Ophthalmol Vis Sci 2020; 60:4759-4773. [PMID: 31738824 DOI: 10.1167/iovs.18-24952] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Reaggregates from E6 embryonic chicken retina exhibit areas corresponding to an inner plexiform layer (IPL), which presents an ideal in vitro model to test conditions and constraints of cholinergic and glutamatergic network formation, providing a basis for retinal tissue engineering. Here, we show that ipl formation is regulated by cholinergic starburst amacrine cells (SACs), a glial scaffold and by L-glutamate. Methods Rosetted spheroids were cultured in absence or presence of 0.2 to 0.4 mM L-glutamate and analyzed by immuno- and enzyme histochemistry, proliferation, and apoptosis assays. Results After 2 days in vitro (div), ipl formation was announced by acetylcholinesterase+ (AChE) and choline acetyltransferase+ (ChAT) cells. Individual vimentin+ or transitin+ Müller glial cell precursors (MCPs) in ipl centers coexpressed ChAT. Comparable to in vivo, pairwise arranged ChAT+ SACs formed two laminar subbands. Projections of calretinin+ amacrine cells (ACs) into ipl associated with MCP processes. In L-glutamate-, or NMDA-treated spheroids ipls were disrupted, including loss of SACs and MCs; coincubation with NMDA receptor inhibitor MK-801 prevented these effects. Also, many Pax6+ cells, comprising most ACs, were lost, while rho4D2+ rod photoreceptors were increased. Cell proliferation was slightly increased, while apoptosis remained unaffected. Conclusions This demonstrated: (1) a far-advanced differentiation of an IPL in retinal spheroids, as never described before; (2) ipl sublamination was initiated by cholinergic precursor cells, which-functioning as "ipl founder cells"-(3) gave rise to neurons and glial cells; (4) these SACs and MCPs together organized ipl formation; and (5) this process was counteracted by NMDA-dependent glutamate actions.
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Affiliation(s)
- Gesine Bachmann
- Developmental Biology and Neurogenetics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Florian Frohns
- Developmental Biology and Neurogenetics, Technische Universität Darmstadt, Darmstadt, Germany.,Radiation Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | - Gopenath Thangaraj
- Developmental Biology and Neurogenetics, Technische Universität Darmstadt, Darmstadt, Germany.,Division of Biotechnology, Faculty of Life Sciences, JSS Academy of Higher Education & Research, Mysuru, India
| | - Alexander Bausch
- Developmental Biology and Neurogenetics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Paul G Layer
- Developmental Biology and Neurogenetics, Technische Universität Darmstadt, Darmstadt, Germany
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21
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Pan Y, Monje M. Activity Shapes Neural Circuit Form and Function: A Historical Perspective. J Neurosci 2020; 40:944-954. [PMID: 31996470 PMCID: PMC6988998 DOI: 10.1523/jneurosci.0740-19.2019] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 12/07/2019] [Accepted: 12/10/2019] [Indexed: 12/30/2022] Open
Abstract
The brilliant and often prescient hypotheses of Ramon y Cajal have proven foundational for modern neuroscience, but his statement that "In adult centers the nerve paths are something fixed, ended, immutable … " is an exception that did not stand the test of empirical study. Mechanisms of cellular and circuit-level plasticity continue to shape and reshape many regions of the adult nervous system long after the neurodevelopmental period. Initially focused on neurons alone, the field has followed a meteoric trajectory in understanding of activity-regulated neurodevelopment and ongoing neuroplasticity with an arc toward appreciating neuron-glial interactions and the role that each neural cell type plays in shaping adaptable neural circuity. In this review, as part of a celebration of the 50th anniversary of Society for Neuroscience, we provide a historical perspective, following this arc of inquiry from neuronal to neuron-glial mechanisms by which activity and experience modulate circuit structure and function. The scope of this consideration is broad, and it will not be possible to cover the wealth of knowledge about all aspects of activity-dependent circuit development and plasticity in depth.
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Affiliation(s)
- Yuan Pan
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California 94305
| | - Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California 94305
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22
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Baram TZ, Donato F, Holmes GL. Construction and disruption of spatial memory networks during development. Learn Mem 2019; 26:206-218. [PMID: 31209115 PMCID: PMC6581006 DOI: 10.1101/lm.049239.118] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 04/02/2019] [Indexed: 01/18/2023]
Abstract
Spatial memory, the aspect of memory involving encoding and retrieval of information regarding one's environment and spatial orientation, is a complex biological function incorporating multiple neuronal networks. Hippocampus-dependent spatial memory is not innate and emerges during development in both humans and rodents. In children, nonhippocampal dependent egocentric (self-to-object) memory develops before hippocampal-dependent allocentric (object-to-object) memory. The onset of allocentric spatial memory abilities in children around 22 mo of age occurs at an age-equivalent time in rodents when spatially tuned grid and place cells arise from patterned activity propagating through the entorhinal-hippocampal circuit. Neuronal activity, often driven by specific sensory signals, is critical for the normal maturation of brain circuits This patterned activity fine-tunes synaptic connectivity of the network and drives the emergence of specific firing necessary for spatial memory. Whereas normal activity patterns are required for circuit maturation, aberrant neuronal activity during development can have major adverse consequences, disrupting the development of spatial memory. Seizures during infancy, involving massive bursts of synchronized network activity, result in impaired spatial memory when animals are tested as adolescents or adults. This impaired spatial memory is accompanied by alterations in spatial and temporal coding of place cells. The molecular mechanisms by which early-life seizures lead to disruptions at the cellular and network levels are now becoming better understood, and provide a target for intervention, potentially leading to improved cognitive outcome in individuals experiencing early-life seizures.
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Affiliation(s)
- Tallie Z Baram
- Department of Anatomy/Neurobiology, University of California-Irvine, Irvine, California 92697, USA
- Department of Pediatrics, University of California-Irvine, Irvine, California 92697, USA
- Department of Neurology, University of California-Irvine, Irvine, California 92697, USA
| | - Flavio Donato
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim 7491, Norway
- Biozentrum, Department of Cell Biology, University of Basel 4056, Switzerland
| | - Gregory L Holmes
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont 05401, USA
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23
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Iqbal J, Zhang K, Jin N, Zhao Y, Liu X, Liu Q, Ni J, Shen L. Alzheimer's Disease Is Responsible for Progressive Age-Dependent Differential Expression of Various Protein Cascades in Retina of Mice. ACS Chem Neurosci 2019; 10:2418-2433. [PMID: 30695639 DOI: 10.1021/acschemneuro.8b00710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disease associated with cognitive impairments and memory loss usually in aged people. In the past few years, it has been detected in the eye retina, manifesting the systematic spread of the disease. This might be used for biomarker discovery for early detection and treatment of the disease. Here, we have described the proteomic alterations in retina of 2, 4, and 6 months old 3×Tg-AD mice by using iTRAQ (isobaric tags for relative and absolute quantification) proteomics technology. Out of the total identified proteins, 121 (71 up- and 50 down-regulated), 79 (51 up- and 28 down-regulated), and 153 (37 up- and 116 down-regulated) significantly differentially expressed proteins (DEPs) are found in 2, 4, and 6 month's mice retina (2, 4, and 6 M), respectively. Seventeen DEPs are found common in these three groups with consistent expression behavior or opposite expression in the three groups. Bioinformatics analysis of these DEPs highlighted their involvement in vital AD-related biological phenomenon. To further prompt the results, four proteins from 2 M group, three from 4 M, and four from 6 M age groups are successfully validated with Western blot analysis. This study confirms the retinal involvement of AD in the form of proteomic differences and further explains the protein-based molecular mechanisms, which might be a step toward biomarker discovery for early detection and treatment of the disease.
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Affiliation(s)
- Javed Iqbal
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, P. R. China
| | - Kaoyuan Zhang
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, P. R. China
- Department of Dermatology, Peking University Shenzhen Hospital, Guangdong 518036, China
| | - Na Jin
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, P. R. China
| | - Yuxi Zhao
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, P. R. China
| | - Xukun Liu
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, P. R. China
| | - Qiong Liu
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, P. R. China
| | - Jiazuan Ni
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, P. R. China
| | - Liming Shen
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, P. R. China
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24
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Holman HA, Poppi LA, Frerck M, Rabbitt RD. Spontaneous and Acetylcholine Evoked Calcium Transients in the Developing Mouse Utricle. Front Cell Neurosci 2019; 13:186. [PMID: 31133810 PMCID: PMC6514437 DOI: 10.3389/fncel.2019.00186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
Spontaneous calcium transients are present during early postnatal development in the mouse retina and cochlea, and play an important role in maturation of the sensory organs and neural circuits in the central nervous system (CNS). It is not known whether similar calcium transients occur during postnatal development in the vestibular sensory organs. Here we demonstrate spontaneous intracellular calcium transients in sensory hair cells (HCs) and supporting cells (SCs) in the murine utricular macula during the first two postnatal weeks. Calcium transients were monitored using a genetically encoded calcium indicator, GCaMP5G (G5), at 100 ms-frame−1 in excised utricle sensory epithelia, including HCs, SCs, and neurons. The reporter line expressed G5 and tdTomato (tdT) in a Gad2-Cre dependent manner within a subset of utricular HCs, SCs and neurons. Kinetics of the G5 reporter limited temporal resolution to calcium events lasting longer than 200 ms. Spontaneous calcium transients lasting 1-2 s were observed in the expressing population of HCs at birth and slower spontaneous transients lasting 10-30 s appeared in SCs by P3. Beginning at P5, calcium transients could be modulated by application of the efferent neurotransmitter acetylcholine (ACh). In mature mice, calcium transients in the utricular macula occurred spontaneously, had a duration 1-2 s, and could be modulated by the exogenous application of acetylcholine (ACh) or muscarine. Long-lasting calcium transients evoked by ACh in mature mice were blocked by atropine, consistent with previous reports describing the role of muscarinic receptors expressed in calyx bearing afferents in efferent control of vestibular sensation. Large spontaneous and ACh evoked transients were reversibly blocked by the inositol trisphosphate receptor (IP3R) antagonist aminoethoxydiphenyl borate (2-APB). Results demonstrate long-lasting calcium transients are present in the utricular macula during the first postnatal week, and that responses to ACh mature over this same time period.
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Affiliation(s)
- Holly A Holman
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Lauren A Poppi
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,School of Biomedical Science and Pharmacy, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia
| | - Micah Frerck
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Richard D Rabbitt
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,Neuroscience Program, University of Utah, Salt Lake City, UT, United States.,Otolaryngology-Head and Neck Surgery, University of Utah, Salt Lake City, UT, United States
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25
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Dalrymple AN, Sharples SA, Osachoff N, Lognon AP, Whelan PJ. A supervised machine learning approach to characterize spinal network function. J Neurophysiol 2019; 121:2001-2012. [PMID: 30943091 DOI: 10.1152/jn.00763.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Spontaneous activity is a common feature of immature neuronal networks throughout the central nervous system and plays an important role in network development and consolidation. In postnatal rodents, spontaneous activity in the spinal cord exhibits complex, stochastic patterns that have historically proven challenging to characterize. We developed a software tool for quickly and automatically characterizing and classifying episodes of spontaneous activity generated from developing spinal networks. We recorded spontaneous activity from in vitro lumbar ventral roots of 16 neonatal [postnatal day (P)0-P3] mice. Recordings were DC coupled and detrended, and episodes were separated for analysis. Amplitude-, duration-, and frequency-related features were extracted from each episode and organized into five classes. Paired classes and features were used to train and test supervised machine learning algorithms. Multilayer perceptrons were used to classify episodes as rhythmic or multiburst. We increased network excitability with potassium chloride and tested the utility of the tool to detect changes in features and episode class. We also demonstrate usability by having a novel experimenter use the program to classify episodes collected at a later time point (P5). Supervised machine learning-based classification of episodes accounted for changes that traditional approaches cannot detect. Our tool, named SpontaneousClassification, advances the detail in which we can study not only developing spinal networks, but also spontaneous networks in other areas of the nervous system. NEW & NOTEWORTHY Spontaneous activity is important for nervous system network development and consolidation. Our software uses machine learning to automatically and quickly characterize and classify episodes of spontaneous activity in the spinal cord of newborn mice. It detected changes in network activity following KCl-enhanced excitation. Using our software to classify spontaneous activity throughout development, in pathological models, or with neuromodulation, may offer insight into the development and organization of spinal circuits.
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Affiliation(s)
- A N Dalrymple
- Neuroscience and Mental Health Institute, University of Alberta , Edmonton, Alberta , Canada
| | - S A Sharples
- Hotchkiss Brain Institute, University of Calgary , Calgary, Alberta , Canada.,Graduate Program in Neuroscience, University of Calgary , Calgary, Alberta , Canada
| | - N Osachoff
- Department of Comparative Biology and Experimental Medicine, University of Calgary , Calgary, Alberta , Canada
| | - A P Lognon
- Hotchkiss Brain Institute, University of Calgary , Calgary, Alberta , Canada.,Graduate Program in Neuroscience, University of Calgary , Calgary, Alberta , Canada
| | - P J Whelan
- Hotchkiss Brain Institute, University of Calgary , Calgary, Alberta , Canada.,Department of Comparative Biology and Experimental Medicine, University of Calgary , Calgary, Alberta , Canada
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26
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Mizuno H, Ikezoe K, Nakazawa S, Sato T, Kitamura K, Iwasato T. Patchwork-Type Spontaneous Activity in Neonatal Barrel Cortex Layer 4 Transmitted via Thalamocortical Projections. Cell Rep 2019; 22:123-135. [PMID: 29298415 DOI: 10.1016/j.celrep.2017.12.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 10/22/2017] [Accepted: 12/01/2017] [Indexed: 12/12/2022] Open
Abstract
Establishment of precise neuronal connectivity in the neocortex relies on activity-dependent circuit reorganization during postnatal development; however, the nature of cortical activity during this period remains largely unknown. Using two-photon calcium imaging of the barrel cortex in vivo during the first postnatal week, we reveal that layer 4 (L4) neurons within the same barrel fire synchronously in the absence of peripheral stimulation, creating a "patchwork" pattern of spontaneous activity corresponding to the barrel map. By generating transgenic mice expressing GCaMP6s in thalamocortical axons, we show that thalamocortical axons also demonstrate the spontaneous patchwork activity pattern. Patchwork activity is diminished by peripheral anesthesia but is mostly independent of self-generated whisker movements. The patchwork activity pattern largely disappeared during postnatal week 2, as even L4 neurons within the same barrel tended to fire asynchronously. This spontaneous L4 activity pattern has features suitable for thalamocortical (TC) circuit refinement in the neonatal barrel cortex.
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Affiliation(s)
- Hidenobu Mizuno
- Division of Neurogenetics, National Institute of Genetics, Mishima 411-8540, Japan; Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima 411-8540, Japan.
| | - Koji Ikezoe
- Department of Neurophysiology, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Shingo Nakazawa
- Division of Neurogenetics, National Institute of Genetics, Mishima 411-8540, Japan; Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima 411-8540, Japan
| | - Takuya Sato
- Division of Neurogenetics, National Institute of Genetics, Mishima 411-8540, Japan
| | - Kazuo Kitamura
- Department of Neurophysiology, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Takuji Iwasato
- Division of Neurogenetics, National Institute of Genetics, Mishima 411-8540, Japan; Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima 411-8540, Japan.
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27
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Imaging Cortical Dynamics in GCaMP Transgenic Rats with a Head-Mounted Widefield Macroscope. Neuron 2018; 100:1045-1058.e5. [PMID: 30482694 DOI: 10.1016/j.neuron.2018.09.050] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 08/03/2018] [Accepted: 09/27/2018] [Indexed: 01/01/2023]
Abstract
Widefield imaging of calcium dynamics is an emerging method for mapping regional neural activity but is currently limited to restrained animals. Here we describe cScope, a head-mounted widefield macroscope developed to image large-scale cortical dynamics in rats during natural behavior. cScope provides a 7.8 × 4 mm field of view and dual illumination paths for both fluorescence and hemodynamic correction and can be fabricated at low cost using readily attainable components. We also report the development of Thy-1 transgenic rat strains with widespread neuronal expression of the calcium indicator GCaMP6f. We combined these two technologies to image large-scale calcium dynamics in the dorsal neocortex during a visual evidence accumulation task. Quantitative analysis of task-related dynamics revealed multiple regions having neural signals that encode behavioral choice and sensory evidence. Our results provide a new transgenic resource for calcium imaging in rats and extend the domain of head-mounted microscopes to larger-scale cortical dynamics. VIDEO ABSTRACT.
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28
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Homeostatic Feedback Modulates the Development of Two-State Patterned Activity in a Model Serotonin Motor Circuit in Caenorhabditis elegans. J Neurosci 2018; 38:6283-6298. [PMID: 29891728 DOI: 10.1523/jneurosci.3658-17.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 06/03/2018] [Accepted: 06/06/2018] [Indexed: 01/31/2023] Open
Abstract
Neuron activity accompanies synapse formation and maintenance, but how early circuit activity contributes to behavior development is not well understood. Here, we use the Caenorhabditis elegans egg-laying motor circuit as a model to understand how coordinated cell and circuit activity develops and drives a robust two-state behavior in adults. Using calcium imaging in behaving animals, we find the serotonergic hermaphrodite-specific neurons (HSNs) and vulval muscles show rhythmic calcium transients in L4 larvae before eggs are produced. HSN activity in L4 is tonic and lacks the alternating burst-firing/quiescent pattern seen in egg-laying adults. Vulval muscle activity in L4 is initially uncoordinated but becomes synchronous as the anterior and posterior muscle arms meet at HSN synaptic release sites. However, coordinated muscle activity does not require presynaptic HSN input. Using reversible silencing experiments, we show that neuronal and vulval muscle activity in L4 is not required for the onset of adult behavior. Instead, the accumulation of eggs in the adult uterus renders the muscles sensitive to HSN input. Sterilization or acute electrical silencing of the vulval muscles inhibits presynaptic HSN activity and reversal of muscle silencing triggers a homeostatic increase in HSN activity and egg release that maintains ∼12-15 eggs in the uterus. Feedback of egg accumulation depends upon the vulval muscle postsynaptic terminus, suggesting that a retrograde signal sustains HSN synaptic activity and egg release. Our results show that egg-laying behavior in C. elegans is driven by a homeostat that scales serotonin motor neuron activity in response to postsynaptic muscle feedback.SIGNIFICANCE STATEMENT The functional importance of early, spontaneous neuron activity in synapse and circuit development is not well understood. Here, we show in the nematode Caenorhabditis elegans that the serotonergic hermaphrodite-specific neurons (HSNs) and postsynaptic vulval muscles show activity during circuit development, well before the onset of adult behavior. Surprisingly, early activity is not required for circuit development or the onset of adult behavior and the circuit remains unable to drive egg laying until fertilized embryos are deposited into the uterus. Egg accumulation potentiates vulval muscle excitability, but ultimately acts to promote burst firing in the presynaptic HSNs which results in egg laying. Our results suggest that mechanosensory feedback acts at three distinct steps to initiate, sustain, and terminate C. elegans egg-laying circuit activity and behavior.
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Abstract
During development, the environment exerts a profound influence on the wiring of brain circuits. Due to the limited resolution of studies in fixed tissue, this experience-dependent structural plasticity was once thought to be restricted to a specific developmental time window. The recent introduction of two-photon microscopy for in vivo imaging has opened the door to repeated monitoring of individual neurons and the study of structural plasticity mechanisms at a very fine scale. In this review, we focus on recent work showing that synaptic structural rearrangements are a key mechanism mediating neural circuit adaptation and behavioral plasticity in the adult brain. We examine this work in the context of classic studies in the visual systems of model organisms, which have laid much of the groundwork for our understanding of activity-dependent synaptic remodeling and its role in brain plasticity.
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Affiliation(s)
- Kalen P Berry
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; .,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Elly Nedivi
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; .,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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Venkatesh H, Monje M. Neuronal Activity in Ontogeny and Oncology. Trends Cancer 2017; 3:89-112. [PMID: 28718448 DOI: 10.1016/j.trecan.2016.12.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 12/29/2016] [Accepted: 12/30/2016] [Indexed: 01/06/2023]
Abstract
The nervous system plays a central role in regulating the stem cell niche in many organs, and thereby pivotally modulates development, homeostasis, and plasticity. A similarly powerful role for neural regulation of the cancer microenvironment is emerging. Neurons promote the growth of cancers of the brain, skin, prostate, pancreas, and stomach. Parallel mechanisms shared in development and cancer suggest that neural modulation of the tumor microenvironment may prove a universal theme, although the mechanistic details of such modulation remain to be discovered for many malignancies. We review here what is known about the influences of active neurons on stem cell and cancer microenvironments across a broad range of tissues, and we discuss emerging principles of neural regulation of development and cancer.
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Affiliation(s)
- Humsa Venkatesh
- Department of Neurology, Stanford University School of Medicine, Stanford, CA, USA; Cancer Biology Graduate Program, Stanford University School of Medicine, Stanford, CA, USA
| | - Michelle Monje
- Department of Neurology, Stanford University School of Medicine, Stanford, CA, USA; Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA; Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA, USA.
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Shoykhet M, Middleton JW. Cardiac Arrest-Induced Global Brain Hypoxia-Ischemia during Development Affects Spontaneous Activity Organization in Rat Sensory and Motor Thalamocortical Circuits during Adulthood. Front Neural Circuits 2016; 10:68. [PMID: 27610077 PMCID: PMC4996986 DOI: 10.3389/fncir.2016.00068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 08/09/2016] [Indexed: 11/13/2022] Open
Abstract
Normal maturation of sensory information processing in the cortex requires patterned synaptic activity during developmentally regulated critical periods. During early development, spontaneous synaptic activity establishes required patterns of synaptic input, and during later development it influences patterns of sensory experience-dependent neuronal firing. Thalamocortical neurons occupy a critical position in regulating the flow of patterned sensory information from the periphery to the cortex. Abnormal thalamocortical inputs may permanently affect the organization and function of cortical neuronal circuits, especially if they occur during a critical developmental window. We examined the effect of cardiac arrest (CA)-associated global brain hypoxia-ischemia in developing rats on spontaneous and evoked firing of somatosensory thalamocortical neurons and on large-scale correlations in the motor thalamocortical circuit. The mean spontaneous and sensory-evoked firing rate activity and variability were higher in CA injured rats. Furthermore, spontaneous and sensory-evoked activity and variability were correlated in uninjured rats, but not correlated in neurons from CA rats. Abnormal activity patterns of ventroposterior medial nucleus (VPm) neurons persisted into adulthood. Additionally, we found that neurons in the entopeduncular nucleus (EPN) in the basal ganglia had lower firing rates yet had higher variability and higher levels of burst firing after injury. Correlated levels of power in local field potentials (LFPs) between the EPN and the motor cortex (MCx) were also disrupted by injury. Our findings indicate that hypoxic-ischemic injury during development leads to abnormal spontaneous and sensory stimulus-evoked input patterns from thalamus to cortex. Abnormal thalamic inputs likely permanently and detrimentally affect the organization of cortical circuitry and processing of sensory information. Hypoxic-ischemic injury also leads to abnormal single neuron and population level activity in the basal ganglia that may contribute to motor dysfunction after injury. Combination of deficits in sensory and motor thalamocortical circuit function may negatively impact sensorimotor integration in CA survivors. Modulation of abnormal activity patterns post-injury may represent a novel therapeutic target to improve neurologic function in survivors.
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Affiliation(s)
- Michael Shoykhet
- Department of Pediatrics, Washington University School of Medicine in St. LouisSt. Louis, MO, USA; Department of Pediatrics, St. Louis Children's HospitalSt. Louis, MO, USA
| | - Jason W Middleton
- Department of Cell Biology and Anatomy, School of Medicine, Louisiana State University Health Sciences CenterNew Orleans, LA, USA; Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences CenterNew Orleans, LA, USA
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Xu H, Tian N. Pathway-Specific Maturation, Visual Deprivation, and Development of Retinal Pathway. Neuroscientist 2016; 10:337-46. [PMID: 15271261 DOI: 10.1177/1073858404265254] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
One of the fundamental features of the visual system is the segregation of neural circuits that process increments and decrements of luminance into ON and OFF pathways. In mature retina, the dendrites of retinal ganglion cells (RGCs) in the inner plexiform layer (IPL) of retina are separated into ON or OFF sublaminaspecific stratification. At an early developmental stage, however, the dendrites of most RGCs are ramified throughout the IPL. The maturation of RGC ON/OFF dendritic stratification requires neural activities mediated by afferent inputs from bipolar and amacrine cells. The synchronized spontaneous burst activities in early postnatal developing retina regulate RGC dendritic filopodial movements and the maintenance or elimination of dendritic processes. After eye opening, visual experience further remodels and consolidates the retinal neural circuit into mature forms. Several neurotransmitter systems, including glutamatergic, acetylcholinergic, GAB Aergic, and glycinergic systems, might act together to modulate the RGC dendritic refinement. In addition, both the bipolar cells and cholinergic amacrine cells may provide laminar cues for the maturation of RGC dendritic stratification.
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Affiliation(s)
- Hongping Xu
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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O'Donovan MJ. Review : Robustness and Self-regulation in the Production of Neural Activity by Developing Networks. Neuroscientist 2016. [DOI: 10.1177/107385849900500106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Spontaneous activity is an important regulator of network development throughout the nervous system. Activity produced in different parts of the developing nervous system shares many features, which suggests that it does not depend on the detailed architecture of developing networks but rather on their common properties. Insights into the mechanisms responsible for generating spontaneous activity have come from recent studies of the spinal cord. Developing spinal networks are hyperexcitable and their immature syn apses are subject to activity-dependent synaptic depression. The conjunction of these properties, which may be common throughout the developing nervous system, is responsible for the spontaneous, episodic activity expressed by spinal networks. These properties endow developing spinal networks with an extremely robust mechanism for generating spontaneous activity that is resistant to major pharmacological and surgical per turbations. NEUROSCIENTIST 5:41-47, 1999
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Affiliation(s)
- Michael J. O'Donovan
- Section on Developmental Neurobiology Laboratory of
Neural Control National Institute of Neurological Disorders and Stroke Bethesda,
Maryland
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Javaid FZ, Brenton J, Guo L, Cordeiro MF. Visual and Ocular Manifestations of Alzheimer's Disease and Their Use as Biomarkers for Diagnosis and Progression. Front Neurol 2016; 7:55. [PMID: 27148157 PMCID: PMC4836138 DOI: 10.3389/fneur.2016.00055] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/29/2016] [Indexed: 12/21/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia affecting the growing aging population today, with prevalence expected to rise over the next 35 years. Clinically, patients exhibit a progressive decline in cognition, memory, and social functioning due to deposition of amyloid β (Aβ) protein and intracellular hyperphosphorylated tau protein. These pathological hallmarks of AD are measured either through neuroimaging, cerebrospinal fluid analysis, or diagnosed post-mortem. Importantly, neuropathological progression occurs in the eye as well as the brain, and multiple visual changes have been noted in both human and animal models of AD. The eye offers itself as a transparent medium to cerebral pathology and has thus potentiated the development of ocular biomarkers for AD. The use of non-invasive screening, such as retinal imaging and visual testing, may enable earlier diagnosis in the clinical setting, minimizing invasive and expensive investigations. It also potentially improves disease management and quality of life for AD patients, as an earlier diagnosis allows initiation of medication and treatment. In this review, we explore the evidence surrounding ocular changes in AD and consider the biomarkers currently in development for early diagnosis.
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Affiliation(s)
- Fatimah Zara Javaid
- Glaucoma and Retinal Degeneration Research Group, Visual Neurosciences, UCL Institute of Ophthalmology, London, UK
| | - Jonathan Brenton
- Glaucoma and Retinal Degeneration Research Group, Visual Neurosciences, UCL Institute of Ophthalmology, London, UK
| | - Li Guo
- Glaucoma and Retinal Degeneration Research Group, Visual Neurosciences, UCL Institute of Ophthalmology, London, UK
| | - Maria F. Cordeiro
- Glaucoma and Retinal Degeneration Research Group, Visual Neurosciences, UCL Institute of Ophthalmology, London, UK
- Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK
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Kirwan P, Turner-Bridger B, Peter M, Momoh A, Arambepola D, Robinson HPC, Livesey FJ. Development and function of human cerebral cortex neural networks from pluripotent stem cells in vitro. Development 2016; 142:3178-87. [PMID: 26395144 PMCID: PMC4582178 DOI: 10.1242/dev.123851] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A key aspect of nervous system development, including that of the cerebral cortex, is the formation of higher-order neural networks. Developing neural networks undergo several phases with distinct activity patterns in vivo, which are thought to prune and fine-tune network connectivity. We report here that human pluripotent stem cell (hPSC)-derived cerebral cortex neurons form large-scale networks that reflect those found in the developing cerebral cortex in vivo. Synchronised oscillatory networks develop in a highly stereotyped pattern over several weeks in culture. An initial phase of increasing frequency of oscillations is followed by a phase of decreasing frequency, before giving rise to non-synchronous, ordered activity patterns. hPSC-derived cortical neural networks are excitatory, driven by activation of AMPA- and NMDA-type glutamate receptors, and can undergo NMDA-receptor-mediated plasticity. Investigating single neuron connectivity within PSC-derived cultures, using rabies-based trans-synaptic tracing, we found two broad classes of neuronal connectivity: most neurons have small numbers (<10) of presynaptic inputs, whereas a small set of hub-like neurons have large numbers of synaptic connections (>40). These data demonstrate that the formation of hPSC-derived cortical networks mimics in vivo cortical network development and function, demonstrating the utility of in vitro systems for mechanistic studies of human forebrain neural network biology. Summary: Human PSC-derived cerebral cortex neurons form large-scale functional networks that change over time and mimic those found in the developing cerebral cortex in vivo.
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Affiliation(s)
- Peter Kirwan
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Benita Turner-Bridger
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Manuel Peter
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Ayiba Momoh
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Devika Arambepola
- Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Hugh P C Robinson
- Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Frederick J Livesey
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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Knipper M, Panford-Walsh R, Singer W, Rüttiger L, Zimmermann U. Specific synaptopathies diversify brain responses and hearing disorders: you lose the gain from early life. Cell Tissue Res 2015; 361:77-93. [PMID: 25843689 PMCID: PMC4487345 DOI: 10.1007/s00441-015-2168-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/05/2015] [Indexed: 01/08/2023]
Abstract
Before hearing onset, inner hair cell (IHC) maturation proceeds under the influence of spontaneous Ca(2+) action potentials (APs). The temporal signature of the IHC Ca(2+) AP is modified through an efferent cholinergic feedback from the medial olivocochlear bundle (MOC) and drives the IHC pre- and post-synapse phenotype towards low spontaneous (spike) rate (SR), high-threshold characteristics. With sensory experience, the IHC pre- and post-synapse phenotype matures towards the instruction of low-SR, high-threshold and of high-SR, low-threshold auditory fiber characteristics. Corticosteroid feedback together with local brain-derived nerve growth factor (BDNF) and catecholaminergic neurotransmitters (dopamine) might be essential for this developmental step. In this review, we address the question of whether the control of low-SR and high-SR fiber characteristics is linked to various degrees of vulnerability of auditory fibers in the mature system. In particular, we examine several IHC synaptopathies in the context of various hearing disorders and exemplified shortfalls before and after hearing onset.
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Affiliation(s)
- Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | | | - Wibke Singer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Ulrike Zimmermann
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
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Ohno Y, Otaki JM. Spontaneous long-range calcium waves in developing butterfly wings. BMC DEVELOPMENTAL BIOLOGY 2015; 15:17. [PMID: 25888365 PMCID: PMC4445562 DOI: 10.1186/s12861-015-0067-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/15/2015] [Indexed: 11/11/2022]
Abstract
Background Butterfly wing color patterns emerge as the result of a regular arrangement of scales produced by epithelial scale cells at the pupal stage. These color patterns and scale arrangements are coordinated throughout the wing. However, the mechanism by which the development of scale cells is controlled across the entire wing remains elusive. In the present study, we used pupal wings of the blue pansy butterfly, Junonia orithya, which has distinct eyespots, to examine the possible involvement of Ca2+ waves in wing development. Results Here, we demonstrate that the developing pupal wing tissue of the blue pansy butterfly displayed spontaneous low-frequency Ca2+ waves in vivo that propagated slowly over long distances. Some waves appeared to be released from the immediate peripheries of the prospective eyespot and discal spot, though it was often difficult to identify the specific origins of these waves. Physical damage, which is known to induce ectopic eyespots, led to the radiation of Ca2+ waves from the immediate periphery of the damaged site. Thapsigargin, which is a specific inhibitor of Ca2+-ATPases in the endoplasmic reticulum, induced an acute increase in cytoplasmic Ca2+ levels and halted the spontaneous Ca2+ waves. Additionally, thapsigargin-treated wings showed incomplete scale development as well as other scale and color pattern abnormalities. Conclusions We identified a novel form of Ca2+ waves, spontaneous low-frequency slow waves, which travel over exceptionally long distances. Our results suggest that spontaneous Ca2+ waves play a critical role in the coordinated development of scale arrangements and possibly in color pattern formation in butterflies. Electronic supplementary material The online version of this article (doi:10.1186/s12861-015-0067-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yoshikazu Ohno
- The BCPH Unit of Molecular Physiology, Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa, 903-0213, Japan.
| | - Joji M Otaki
- The BCPH Unit of Molecular Physiology, Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa, 903-0213, Japan.
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Martynyuk NY, Purnyn’ EE, Fedulova SA. Effect of a Blocker of Nicotine Acetylcholine Receptors on Excitatory Postsynaptic Currents in Ganglion Cells of the Rat Retina. NEUROPHYSIOLOGY+ 2015. [DOI: 10.1007/s11062-015-9482-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lansdell B, Ford K, Kutz JN. A reaction-diffusion model of cholinergic retinal waves. PLoS Comput Biol 2014; 10:e1003953. [PMID: 25474327 PMCID: PMC4256014 DOI: 10.1371/journal.pcbi.1003953] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 10/01/2014] [Indexed: 01/21/2023] Open
Abstract
Prior to receiving visual stimuli, spontaneous, correlated activity in the retina, called retinal waves, drives activity-dependent developmental programs. Early-stage waves mediated by acetylcholine (ACh) manifest as slow, spreading bursts of action potentials. They are believed to be initiated by the spontaneous firing of Starburst Amacrine Cells (SACs), whose dense, recurrent connectivity then propagates this activity laterally. Their inter-wave interval and shifting wave boundaries are the result of the slow after-hyperpolarization of the SACs creating an evolving mosaic of recruitable and refractory cells, which can and cannot participate in waves, respectively. Recent evidence suggests that cholinergic waves may be modulated by the extracellular concentration of ACh. Here, we construct a simplified, biophysically consistent, reaction-diffusion model of cholinergic retinal waves capable of recapitulating wave dynamics observed in mice retina recordings. The dense, recurrent connectivity of SACs is modeled through local, excitatory coupling occurring via the volume release and diffusion of ACh. In addition to simulation, we are thus able to use non-linear wave theory to connect wave features to underlying physiological parameters, making the model useful in determining appropriate pharmacological manipulations to experimentally produce waves of a prescribed spatiotemporal character. The model is used to determine how ACh mediated connectivity may modulate wave activity, and how parameters such as the spontaneous activation rate and sAHP refractory period contribute to critical wave size variability.
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Affiliation(s)
- Benjamin Lansdell
- Department of Applied Mathematics, University of Washington, Seattle, Washington, United States of America
| | - Kevin Ford
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - J. Nathan Kutz
- Department of Applied Mathematics, University of Washington, Seattle, Washington, United States of America
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Speer CM, Sun C, Liets LC, Stafford BK, Chapman B, Cheng HJ. Eye-specific retinogeniculate segregation proceeds normally following disruption of patterned spontaneous retinal activity. Neural Dev 2014; 9:25. [PMID: 25377639 PMCID: PMC4289266 DOI: 10.1186/1749-8104-9-25] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 10/20/2014] [Indexed: 11/10/2022] Open
Abstract
Background Spontaneous retinal activity (SRA) is important during eye-specific segregation within the dorsal lateral geniculate nucleus (dLGN), but the feature(s) of activity critical for retinogeniculate refinement are controversial. Pharmacologically or genetically manipulating cholinergic signaling during SRA perturbs correlated retinal ganglion cell (RGC) spiking and disrupts eye-specific retinofugal refinement in vivo, consistent with an instructive role for SRA during visual system development. Paradoxically, ablating the starburst amacrine cells (SACs) that generate cholinergic spontaneous activity disrupts correlated RGC firing without impacting retinal activity levels or eye-specific segregation in the dLGN. Such experiments suggest that patterned SRA during retinal waves is not critical for eye-specific refinement and instead, normal activity levels are permissive for retinogeniculate development. Here we revisit the effects of ablating the cholinergic network during eye-specific segregation and show that SAC ablation disrupts, but does not eliminate, retinal waves with no concomitant impact on normal eye-specific segregation in the dLGN. Results We induced SAC ablation in postnatal ferret pups beginning at birth by intraocular injection of a novel immunotoxin selective for the ferret vesicular acetylcholine transporter (Ferret VAChT-Sap). Through dual-patch whole-cell and multi-electrode array recording we found that SAC ablation altered SRA patterns and led to significantly smaller retinal waves compared with controls. Despite these defects, eye-specific segregation was normal. Further, interocular competition for target territory in the dLGN proceeded in cases where SAC ablation was asymmetric in the two eyes. Conclusions Our data demonstrate normal eye-specific retinogeniculate development despite significant abnormalities in patterned SRA. Comparing our current results with earlier studies suggests that defects in retinal wave size, absolute levels of SRA, correlations between RGC pairs, RGC burst frequency, high frequency RGC firing during bursts, and the number of spikes per RGC burst are each uncorrelated with abnormalities in eye-specific segregation in the dLGN. An increase in the fraction of asynchronous spikes occurring outside of bursts and waves correlates with eye-specific segregation defects in studies reported to date. These findings highlight the relative importance of different features of SRA while providing additional constraints for computational models of Hebbian plasticity mechanisms in the developing visual system. Electronic supplementary material The online version of this article (doi:10.1186/1749-8104-9-25) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Hwai-Jong Cheng
- Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA 95618, USA.
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Takeuchi H, Suzumura A. Gap junctions and hemichannels composed of connexins: potential therapeutic targets for neurodegenerative diseases. Front Cell Neurosci 2014; 8:189. [PMID: 25228858 PMCID: PMC4151093 DOI: 10.3389/fncel.2014.00189] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/19/2014] [Indexed: 12/03/2022] Open
Abstract
Microglia are macrophage-like resident immune cells that contribute to the maintenance of homeostasis in the central nervous system (CNS). Abnormal activation of microglia can cause damage in the CNS, and accumulation of activated microglia is a characteristic pathological observation in neurologic conditions such as trauma, stroke, inflammation, epilepsy, and neurodegenerative diseases. Activated microglia secrete high levels of glutamate, which damages CNS cells and has been implicated as a major cause of neurodegeneration in these conditions. Glutamate-receptor blockers and microglia inhibitors (e.g., minocycline) have been examined as therapeutic candidates for several neurodegenerative diseases; however, these compounds exerted little therapeutic benefit because they either perturbed physiological glutamate signals or suppressed the actions of protective microglia. The ideal therapeutic approach would hamper the deleterious roles of activated microglia without diminishing their protective effects. We recently found that abnormally activated microglia secrete glutamate via gap-junction hemichannels on the cell surface. Moreover, administration of gap-junction inhibitors significantly suppressed excessive microglial glutamate release and improved disease symptoms in animal models of neurologic conditions such as stroke, multiple sclerosis, amyotrophic lateral sclerosis, and Alzheimer's disease. Recent evidence also suggests that neuronal and glial communication via gap junctions amplifies neuroinflammation and neurodegeneration. Elucidation of the precise pathologic roles of gap junctions and hemichannels may lead to a novel therapeutic strategies that can slow and halt the progression of neurodegenerative diseases.
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Affiliation(s)
- Hideyuki Takeuchi
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University Nagoya, Japan
| | - Akio Suzumura
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University Nagoya, Japan
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Assali A, Gaspar P, Rebsam A. Activity dependent mechanisms of visual map formation--from retinal waves to molecular regulators. Semin Cell Dev Biol 2014; 35:136-46. [PMID: 25152335 DOI: 10.1016/j.semcdb.2014.08.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/12/2014] [Accepted: 08/15/2014] [Indexed: 01/31/2023]
Abstract
The refinement of neural connections requires activity-dependent mechanisms in addition to the genetic program initially establishing wiring diagrams. The well-understood organization of the visual system makes it an accessible model for analyzing the contribution of activity in the formation of connectivity. Prior to visual experience, patterned spontaneous activity in the form of retinal waves has an important role for the establishment of eye-specific and retinotopic maps by acting on the refinement of axon arborization. In the present review, which focuses on experimental data obtained in mice and ferrets, we highlight the features of retinal activity that are important for visual map formation and question whether synaptic release and Hebbian based competition rules apply to this system. Recent evidence using genetic tools that allowed the manipulation of different features of neural activity have clarified the controversy on whether activity is instructive or permissive for visual map formation. Furthermore, current evidence strongly suggests that different mechanisms are at play for different types of axons (ipsilateral vs. contralateral), maps (eye-specific vs. retinotopic) or targets. Many molecules that either modulate activity or are modulated by activity are important in the formation of the visual map, such as adenylate cyclase 1, serotonin, or molecules from the immune system. Finally, new players in the game include retrograde messengers signaling from the target cell to the retinal axons as well as microglia that could help to eliminate inappropriate synapses.
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Affiliation(s)
- Ahlem Assali
- Inserm UMR-S839, Paris, 75005, France; Université Pierre & Marie Curie (UPMC), Sorbonne Universités, Paris, France; Institut du Fer à Moulin, Paris, 75005, France.
| | - Patricia Gaspar
- Inserm UMR-S839, Paris, 75005, France; Université Pierre & Marie Curie (UPMC), Sorbonne Universités, Paris, France; Institut du Fer à Moulin, Paris, 75005, France.
| | - Alexandra Rebsam
- Inserm UMR-S839, Paris, 75005, France; Université Pierre & Marie Curie (UPMC), Sorbonne Universités, Paris, France; Institut du Fer à Moulin, Paris, 75005, France.
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Ackman JB, Crair MC. Role of emergent neural activity in visual map development. Curr Opin Neurobiol 2013; 24:166-75. [PMID: 24492092 DOI: 10.1016/j.conb.2013.11.011] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 11/12/2013] [Accepted: 11/22/2013] [Indexed: 11/24/2022]
Abstract
The initial structural and functional development of visual circuits in reptiles, birds, and mammals happens independent of sensory experience. After eye opening, visual experience further refines and elaborates circuits that are critical for normal visual function. Innate genetic programs that code for gradients of molecules provide gross positional information for developing nerve cells, yet much of the cytoarchitectural complexity and synaptogenesis of neurons depends on calcium influx, neurotransmitter release, and neural activity before the onset of vision. In fact, specific spatiotemporal patterns of neural activity, or 'retinal waves', emerge amidst the development of the earliest connections made between excitable cells in the developing eye. These patterns of spontaneous activity, which have been observed in all amniote retinae examined to date, may be an evolved adaptation for species with long gestational periods before the onset of functional vision, imparting an informational robustness and redundancy to guide development of visual maps across the nervous system. Recent experiments indicate that retinal waves play a crucial role in the development of interconnections between different parts of the visual system, suggesting that these spontaneous patterns serve as a template-matching mechanism to prepare higher-order visually associative circuits for the onset of visuomotor learning and behavior. Key questions for future studies include determining the exact sources and nature of spontaneous activity during development, characterizing the interactions between neural activity and transcriptional gene regulation, and understanding the extent of circuit connectivity governed by retinal waves within and between sensory-motor systems.
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Affiliation(s)
- James B Ackman
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, United States
| | - Michael C Crair
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, United States; Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06510, United States; Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510, United States.
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Affiliation(s)
- Hideyuki Takeuchi
- Department of Neuroimmunology; Research Institute of Environmental Medicine; Nagoya University; Nagoya Japan
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Abstract
Throughout development, the nervous system produces patterned spontaneous activity. Research over the past two decades has revealed a core group of mechanisms that mediate spontaneous activity in diverse circuits. Many circuits engage several of these mechanisms sequentially to accommodate developmental changes in connectivity. In addition to shared mechanisms, activity propagates through developing circuits and neuronal pathways (i.e., linked circuits in different brain areas) in stereotypic patterns. Increasing evidence suggests that spontaneous network activity shapes synaptic development in vivo Variations in activity-dependent plasticity may explain how similar mechanisms and patterns of activity can be employed to establish diverse circuits. Here, I will review common mechanisms and patterns of spontaneous activity in emerging neural networks and discuss recent insights into their contribution to synaptic development.
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Affiliation(s)
- Daniel Kerschensteiner
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, MO, USA Department of Anatomy and Neurobiology, Washington University School of Medicine, Saint Louis, MO, USA Hope Center for Neurological Disorders, Washington University School of Medicine, Saint Louis, MO, USA
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Malmersjö S, Rebellato P, Smedler E, Uhlén P. Small-world networks of spontaneous Ca(2+) activity. Commun Integr Biol 2013; 6:e24788. [PMID: 23986813 PMCID: PMC3742060 DOI: 10.4161/cib.24788] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 04/23/2013] [Indexed: 11/19/2022] Open
Abstract
Synchronized network activity among groups of interconnected cells is essential for diverse functions in the brain. However, most studies have been made on cellular networks in the mature brain when chemical synapses have been formed. Much less is known about the situation earlier in development. When studying neural progenitors derived from embryonic stem cells and neural progenitors from mice embryos, we found networks of gap junction coupled cells with vivid spontaneous non-random calcium (Ca2+) activity driven by electrical depolarization that stimulated cell growth. Network activity was revealed by single-cell live Ca2+ imaging and further analyzed for correlations and network topology. The analysis revealed the networks to have small-world characteristics with scale-free properties. Taken together, these results demonstrate that immature cells in the developing brain organize in small-world networks that critically regulate neural progenitor proliferation.
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Affiliation(s)
- Seth Malmersjö
- Department of Medical Biochemistry and Biophysics; Karolinska Institutet; Stockholm, Sweden ; Department of Chemical and Systems Biology; School of Medicine; Stanford University; Stanford, CA USA
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Neural progenitors organize in small-world networks to promote cell proliferation. Proc Natl Acad Sci U S A 2013; 110:E1524-32. [PMID: 23576737 DOI: 10.1073/pnas.1220179110] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Coherent network activity among assemblies of interconnected cells is essential for diverse functions in the adult brain. However, cellular networks before formations of chemical synapses are poorly understood. Here, embryonic stem cell-derived neural progenitors were found to form networks exhibiting synchronous calcium ion (Ca(2+)) activity that stimulated cell proliferation. Immature neural cells established circuits that propagated electrical signals between neighboring cells, thereby activating voltage-gated Ca(2+) channels that triggered Ca(2+) oscillations. These network circuits were dependent on gap junctions, because blocking prevented electrotonic transmission both in vitro and in vivo. Inhibiting connexin 43 gap junctions abolished network activity, suppressed proliferation, and affected embryonic cortical layer formation. Cross-correlation analysis revealed highly correlated Ca(2+) activities in small-world networks that followed a scale-free topology. Graph theory predicts that such network designs are effective for biological systems. Taken together, these results demonstrate that immature cells in the developing brain organize in small-world networks that critically regulate neural progenitor proliferation.
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Reh TA. The Development of the Retina. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00013-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Before vision, a transient network of recurrently connected cholinergic interneurons, called starburst amacrine cells (SACs), generates spontaneous retinal waves. Despite an absence of robust inhibition, cholinergic retinal waves initiate infrequently and propagate within finite boundaries. Here, we combine a variety of electrophysiological and imaging techniques and computational modeling to elucidate the mechanisms underlying these spatial and temporal properties of waves in developing mouse retina. Waves initiate via rare spontaneous depolarizations of SACs. Waves propagate through recurrent cholinergic connections between SACs and volume release of ACh as demonstrated using paired recordings and a cell-based ACh optical sensor. Perforated-patch recordings and two-photon calcium imaging reveal that individual SACs have slow afterhyperpolarizations that induce SACs to have variable depolarizations during sequential waves. Using a computational model in which the properties of SACs are based on these physiological measurements, we reproduce the slow frequency, speed, and finite size of recorded waves. This study represents a detailed description of the circuit that mediates cholinergic retinal waves and indicates that variability of the interneurons that generate this network activity may be critical for the robustness of waves across different species and stages of development.
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Kleindienst T, Winnubst J, Roth-Alpermann C, Bonhoeffer T, Lohmann C. Activity-dependent clustering of functional synaptic inputs on developing hippocampal dendrites. Neuron 2012; 72:1012-24. [PMID: 22196336 DOI: 10.1016/j.neuron.2011.10.015] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2011] [Indexed: 11/29/2022]
Abstract
During brain development, before sensory systems become functional, neuronal networks spontaneously generate repetitive bursts of neuronal activity, which are typically synchronized across many neurons. Such activity patterns have been described on the level of networks and cells, but the fine-structure of inputs received by an individual neuron during spontaneous network activity has not been studied. Here, we used calcium imaging to record activity at many synapses of hippocampal pyramidal neurons simultaneously to establish the activity patterns in the majority of synapses of an entire cell. Analysis of the spatiotemporal patterns of synaptic activity revealed a fine-scale connectivity rule: neighboring synapses (<16 μm intersynapse distance) are more likely to be coactive than synapses that are farther away from each other. Blocking spiking activity or NMDA receptor activation revealed that the clustering of synaptic inputs required neuronal activity, demonstrating a role of developmentally expressed spontaneous activity for connecting neurons with subcellular precision.
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Affiliation(s)
- Thomas Kleindienst
- Netherlands Institute for Neuroscience, 1105 BA Amsterdam, The Netherlands
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