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Lohof AM, Dufor T, Sherrard RM. Neural Circuit Repair by Low-Intensity rTMS. CEREBELLUM (LONDON, ENGLAND) 2022; 21:750-754. [PMID: 35023064 DOI: 10.1007/s12311-021-01354-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/25/2021] [Indexed: 06/14/2023]
Abstract
Electromagnetic brain stimulation is a promising treatment in neurology and psychiatry. However, clinical outcomes are variable and underlying mechanisms remain ill-defined, impeding the development of new effective stimulation protocols. There is increasing application of repetitive transcranial magnetic stimulation (rTMS) to the cerebellum to induce forebrain plasticity through its long-distance cerebello-cerebral circuits. To better understand what magnetic stimulation does within the cerebellum, we have developed tools to generate defined low-intensity (LI) magnetic fields and deliver them in vivo, in 3D organotypic culture and in primary cultures, over a range of stimulation parameters. Here we show that low-intensity rTMS (LI-rTMS) to the cerebellum induces axon growth and synapse formation providing olivocerebellar reinnervation. This repair depends on stimulation pattern, with complex biomimetic patterns being most effective, and this requires the presence of a cellular magnetoreceptor, cryptochrome. To explain these reparative changes, we found that repair-promoting LI-rTMS patterns, but not ineffective ones, increased c-fos expression in Purkinje neurons, consistent with the production of reactive oxygen species by activated cryptochrome. Rather than activating neurons via induced electric currents, we propose that weak magnetic fields act through cryptochrome, activating intracellular signals that induce climbing fibre-Purkinje cell reinnervation. This information opens new routes to optimize cerebellar magnetic stimulation and its potential role as an effective treatment for neurological diseases.
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Affiliation(s)
- A M Lohof
- Sorbonne Université and CNRS, IBPS-B2A UMR8256 Biological Adaptation and Ageing, Boite 256, 9 Quai St Bernard, 75005, Paris, France
| | - T Dufor
- Sorbonne Université and CNRS, IBPS-B2A UMR8256 Biological Adaptation and Ageing, Boite 256, 9 Quai St Bernard, 75005, Paris, France
| | - R M Sherrard
- Sorbonne Université and CNRS, IBPS-B2A UMR8256 Biological Adaptation and Ageing, Boite 256, 9 Quai St Bernard, 75005, Paris, France.
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2
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Beekhof GC, Osório C, White JJ, van Zoomeren S, van der Stok H, Xiong B, Nettersheim IH, Mak WA, Runge M, Fiocchi FR, Boele HJ, Hoebeek FE, Schonewille M. Differential spatiotemporal development of Purkinje cell populations and cerebellum-dependent sensorimotor behaviors. eLife 2021; 10:63668. [PMID: 33973524 PMCID: PMC8195607 DOI: 10.7554/elife.63668] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 05/10/2021] [Indexed: 12/17/2022] Open
Abstract
Distinct populations of Purkinje cells (PCs) with unique molecular and connectivity features are at the core of the modular organization of the cerebellum. Previously, we showed that firing activity of PCs differs between ZebrinII-positive and ZebrinII-negative cerebellar modules (Zhou et al., 2014; Wu et al., 2019). Here, we investigate the timing and extent of PC differentiation during development in mice. We found that several features of PCs, including activity levels, dendritic arborization, axonal shape and climbing fiber input, develop differentially between nodular and anterior PC populations. Although all PCs show a particularly rapid development in the second postnatal week, anterior PCs typically have a prolonged physiological and dendritic maturation. In line herewith, younger mice exhibit attenuated anterior-dependent eyeblink conditioning, but faster nodular-dependent compensatory eye movement adaptation. Our results indicate that specific cerebellar regions have unique developmental timelines which match with their related, specific forms of cerebellum-dependent behaviors.
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Affiliation(s)
| | - Catarina Osório
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Joshua J White
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | | | - Bilian Xiong
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | | | - Marit Runge
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | - Henk-Jan Boele
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Princeton Neuroscience Institute, Princeton, United States
| | - Freek E Hoebeek
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Department for Developmental Origins of Disease, University Medical Center Utrecht Brain Center and Wilhelmina Children's Hospital, Utrecht, Netherlands
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3
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Sathyanesan A, Zhou J, Scafidi J, Heck DH, Sillitoe RV, Gallo V. Emerging connections between cerebellar development, behaviour and complex brain disorders. Nat Rev Neurosci 2019; 20:298-313. [PMID: 30923348 DOI: 10.1038/s41583-019-0152-2] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The human cerebellum has a protracted developmental timeline compared with the neocortex, expanding the window of vulnerability to neurological disorders. As the cerebellum is critical for motor behaviour, it is not surprising that most neurodevelopmental disorders share motor deficits as a common sequela. However, evidence gathered since the late 1980s suggests that the cerebellum is involved in motor and non-motor function, including cognition and emotion. More recently, evidence indicates that major neurodevelopmental disorders such as intellectual disability, autism spectrum disorder, attention-deficit hyperactivity disorder and Down syndrome have potential links to abnormal cerebellar development. Out of recent findings from clinical and preclinical studies, the concept of the 'cerebellar connectome' has emerged that can be used as a framework to link the role of cerebellar development to human behaviour, disease states and the design of better therapeutic strategies.
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Affiliation(s)
- Aaron Sathyanesan
- Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, DC, USA.
| | - Joy Zhou
- Department of Pathology and Immunology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Joseph Scafidi
- Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, DC, USA.,George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Detlef H Heck
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
| | - Vittorio Gallo
- Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, DC, USA. .,George Washington University School of Medicine and Health Sciences, Washington, DC, USA.
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4
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Beckinghausen J, Sillitoe RV. Insights into cerebellar development and connectivity. Neurosci Lett 2018; 688:2-13. [PMID: 29746896 DOI: 10.1016/j.neulet.2018.05.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 05/04/2018] [Accepted: 05/06/2018] [Indexed: 02/06/2023]
Abstract
The cerebellum has a well-established role in controlling motor functions such coordination, balance, posture, and skilled learning. There is mounting evidence that it might also play a critical role in non-motor functions such as cognition and emotion. It is therefore not surprising that cerebellar defects are associated with a wide array of diseases including ataxia, dystonia, tremor, schizophrenia, dyslexia, and autism spectrum disorder. What is intriguing is that a seemingly uniform circuit that is often described as being "simple" should carry out all of these behaviors. Analyses of how cerebellar circuits develop have revealed that such descriptions massively underestimate the complexity of the cerebellum. The cerebellum is in fact highly patterned and organized around a series of parasagittal stripes and transverse zones. This topographic architecture partitions all cerebellar circuits into functional modules that are thought to enhance processing power during cerebellar dependent behaviors. What are arguably the most remarkable features of cerebellar topography are the developmental processes that produce them. This review is concerned with the genetic and cellular mechanisms that orchestrate cerebellar patterning. We place a major focus on how Purkinje cells control multiple aspects of cerebellar circuit assembly. Using this model, we discuss evidence for how "zebra-like" patterns in Purkinje cells sculpt the cerebellum, how specific genetic cues mediate the process, and how activity refines the patterns into an adult map that is capable of executing various functions. We also discuss how defective Purkinje cell patterning might impact the pathogenesis of neurological conditions.
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Affiliation(s)
- Jaclyn Beckinghausen
- Department of Pathology and Immunology, 1250 Moursund Street, Suite 1325, Houston, TX 77030, USA; Department of Neuroscience, 1250 Moursund Street, Suite 1325, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute of TX Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, 1250 Moursund Street, Suite 1325, Houston, TX 77030, USA; Department of Neuroscience, 1250 Moursund Street, Suite 1325, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA; Jan and Dan Duncan Neurological Research Institute of TX Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA.
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5
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Grehl S, Martina D, Goyenvalle C, Deng ZD, Rodger J, Sherrard RM. In vitro Magnetic Stimulation: A Simple Stimulation Device to Deliver Defined Low Intensity Electromagnetic Fields. Front Neural Circuits 2016; 10:85. [PMID: 27857683 PMCID: PMC5093126 DOI: 10.3389/fncir.2016.00085] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/10/2016] [Indexed: 01/10/2023] Open
Abstract
Non-invasive brain stimulation (NIBS) by electromagnetic fields appears to benefit human neurological and psychiatric conditions, although the optimal stimulation parameters and underlying mechanisms remain unclear. Although, in vitro studies have begun to elucidate cellular mechanisms, stimulation is delivered by a range of coils (from commercially available human stimulation coils to laboratory-built circuits) so that the electromagnetic fields induced within the tissue to produce the reported effects are ill-defined. Here, we develop a simple in vitro stimulation device with plug-and-play features that allow delivery of a range of stimulation parameters. We chose to test low intensity repetitive magnetic stimulation (LI-rMS) delivered at three frequencies to hindbrain explant cultures containing the olivocerebellar pathway. We used computational modeling to define the parameters of a stimulation circuit and coil that deliver a unidirectional homogeneous magnetic field of known intensity and direction, and therefore a predictable electric field, to the target. We built the coil to be compatible with culture requirements: stimulation within an incubator; a flat surface allowing consistent position and magnetic field direction; location outside the culture plate to maintain sterility and no heating or vibration. Measurements at the explant confirmed the induced magnetic field was homogenous and matched the simulation results. To validate our system we investigated biological effects following LI-rMS at 1 Hz, 10 Hz and biomimetic high frequency, which we have previously shown induces neural circuit reorganization. We found that gene expression was modified by LI-rMS in a frequency-related manner. Four hours after a single 10-min stimulation session, the number of c-fos positive cells increased, indicating that our stimulation activated the tissue. Also, after 14 days of LI-rMS, the expression of genes normally present in the tissue was differentially modified according to the stimulation delivered. Thus we describe a simple magnetic stimulation device that delivers defined stimulation parameters to different neural systems in vitro. Such devices are essential to further understanding of the fundamental effects of magnetic stimulation on biological tissue and optimize therapeutic application of human NIBS.
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Affiliation(s)
- Stephanie Grehl
- Sorbonne Universités, UPMC Univ Paris 06 & CNRS, IBPS-B2A, UMR 8256 Biological Adaptation and AgeingParis, France; Experimental and Regenerative Neuroscience, School of Animal Biology, the University of Western Australia, PerthWA, Australia
| | - David Martina
- Institut Langevin, ESPCI ParisTech & CNRS, UMR7587 INSERM ERL U979 Paris, France
| | - Catherine Goyenvalle
- Sorbonne Universités, UPMC Univ Paris 06 & CNRS, IBPS-B2A, UMR 8256 Biological Adaptation and Ageing Paris, France
| | - Zhi-De Deng
- Non-invasive Neuromodulation Unit, Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, BethesdaMD, USA; Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, DurhamNC, USA
| | - Jennifer Rodger
- Experimental and Regenerative Neuroscience, School of Animal Biology, the University of Western Australia, Perth WA, Australia
| | - Rachel M Sherrard
- Sorbonne Universités, UPMC Univ Paris 06 & CNRS, IBPS-B2A, UMR 8256 Biological Adaptation and Ageing Paris, France
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6
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Morellini N, Grehl S, Tang A, Rodger J, Mariani J, Lohof AM, Sherrard RM. What does low-intensity rTMS do to the cerebellum? THE CEREBELLUM 2015; 14:23-6. [PMID: 25346177 DOI: 10.1007/s12311-014-0617-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Non-invasive stimulation of the human cerebellum, such as by transcranial magnetic stimulation (TMS), is increasingly used to investigate cerebellar function and identify potential treatment for cerebellar dysfunction. However, the effects of TMS on cerebellar neurons remain poorly defined. We applied low-intensity repetitive TMS (LI-rTMS) to the mouse cerebellum in vivo and in vitro and examined the cellular and molecular sequelae. In normal C57/Bl6 mice, 4 weeks of LI-rTMS using a complex biomimetic high-frequency stimulation (BHFS) alters Purkinje cell (PC) dendritic and spine morphology; the effects persist 4 weeks after the end of stimulation. We then evaluated whether LI-rTMS could induce climbing fibre (CF) reinnervation to denervated PCs. After unilateral pedunculotomy in adult mice and 2 weeks sham or BHFS stimulation, VGLUT2 immunohistochemistry was used to quantify CF reinnervation. In contrast to sham, LI-rTMS induced CF reinnervation to the denervated hemicerebellum. To examine potential mechanisms underlying the LI-rTMS effect, we verified that BHFS could induce CF reinnervation using our in vitro olivocerebellar explants in which denervated cerebellar tissue is co-cultured adjacent to intact cerebella and treated with brain-derived neurotrophic factor (BDNF) (as a positive control), sham or LI-rTMS for 2 weeks. Compared with sham, BDNF and BHFS LI-rTMS significantly increased CF reinnervation, without additive effect. To identify potential underlying mechanisms, we examined intracellular calcium flux during the 10-min stimulation. Complex high-frequency stimulation increased intracellular calcium by release from intracellular stores. Thus, even at low intensity, rTMS modifies PC structure and induces CF reinnervation.
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Affiliation(s)
- N Morellini
- UMR8256 Biological Adaptation and Ageing, IBPS-B2A, Sorbonne Universités UPMC-Univ Paris 6 and CNRS, 75005, Paris, France
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7
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Redefining the cerebellar cortex as an assembly of non-uniform Purkinje cell microcircuits. Nat Rev Neurosci 2015; 16:79-93. [PMID: 25601779 DOI: 10.1038/nrn3886] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The adult mammalian cerebellar cortex is generally assumed to have a uniform cytoarchitecture. Differences in cerebellar function are thought to arise primarily through distinct patterns of input and output connectivity rather than as a result of variations in cortical microcircuitry. However, evidence from anatomical, physiological and genetic studies is increasingly challenging this orthodoxy, and there are now various lines of evidence indicating that the cerebellar cortex is not uniform. Here, we develop the hypothesis that regional differences in properties of cerebellar cortical microcircuits lead to important differences in information processing.
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8
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Sherrard RM, Letellier M, Lohof AM, Mariani J. Formation and reformation of climbing fibre synapses in the cerebellum: a similar story? THE CEREBELLUM 2013; 12:319-21. [PMID: 23325508 DOI: 10.1007/s12311-012-0443-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The assembly of neural circuits involves multiple sequential steps, in particular the formation and maturation of synaptic connections. This often prolonged process involves several stages including the appropriate morphological and physiological maturation of each synaptic partner as well as their mutual interaction in order to ensure correct cellular and subcellular targeting. Understanding the processes involved becomes critical if neural circuits are to be appropriately reassembled following lesion, atrophy or neurodegeneration. We study the climbing fibre to Purkinje cell synapse as an example of a neural circuit which undergoes initial synaptic formation, selective stabilisation and elimination of redundant connections, in order to better understand the relative roles of each synaptic partner in the process of synaptogenesis and post-lesion synapse reformation. In particular, we are interested in the molecules which may underlie these processes. Here, we present data showing that the maturational state of both the target Purkinje cell and the climbing fibre axon influence their capacity for synapse formation. The climbing fibre retains some ability to recapitulate developmental processes irrespective of its maturational state. In contrast, the experience of synaptic formation and selective stabilisation/elimination permanently changes the Purkinje cell so that it cannot be repeated. Thus, if the climbing fibre-Purkinje cell synapse is recreated after the period of normal maturation, the process of synaptic competition, involving the gradual weakening of one climbing fibre synapse and stabilisation of another, no longer takes place. Moreover, we show that these processes of synaptic competition can only proceed during a specific developmental phase. To understand why these changes occur, we have investigated the role of molecules involved in the development of the olivocerebellar path and show that brain-derived neurotrophic factor, through activation of its receptor TrkB, as well as polysialated neural cell adhesion molecule and the transcription factor RORα regulate these processes.
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Affiliation(s)
- Rachel M Sherrard
- UPMC Univ Paris 6 and CNRS, UMR 7102 Neurobiologie des Processus Adaptatifs, Paris, France.
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9
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Affiliation(s)
| | - Richard Hawkes
- Department of Cell Biology and Anatomy, Genes and Development Research Group and Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary
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10
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White JJ, Sillitoe RV. Development of the cerebellum: from gene expression patterns to circuit maps. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 2:149-64. [DOI: 10.1002/wdev.65] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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11
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Wilson SL, Kalinovsky A, Orvis GD, Joyner AL. Spatially restricted and developmentally dynamic expression of engrailed genes in multiple cerebellar cell types. THE CEREBELLUM 2012; 10:356-72. [PMID: 21431469 DOI: 10.1007/s12311-011-0254-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cerebellum is a highly organized structure partitioned into lobules along the anterior-posterior (A-P) axis and into striped molecular domains along the medial-lateral (M-L) axis. The Engrailed (En) homeobox genes are required for patterning the morphological and molecular domains along both axes, as well as for the establishment of the normal afferent topography required to generate a fully functional cerebellum. As a means to understand how the En genes regulate multiple levels of cerebellum construction, we characterized En1 and En2 expression around birth and at postnatal day (P) 21 during the period when the cerebellum undergoes a remarkable transformation from a smooth ovoid structure to a highly foliated structure. We show that both En1 and En2 are expressed in many neuronal cell types in the cerebellum, and expression persists until at least P21. En1 and En2 expression, however, undergoes profound changes in their cellular and spatial distributions between embryonic stages and P21, and their expression domains become largely distinct. Comparison of the distribution of En-expressing Purkinje cells relative to early- and late-onset Purkinje cell M-L stripe proteins revealed that although En1- and En2-expressing Purkinje cell domains do not strictly align with those of ZEBRINII at P21, a clear pattern exists that is most evident at E17.5 by an inverse correlation between the level of En2 expression and PLCß4 and EPHA4.
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Affiliation(s)
- Sandra L Wilson
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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12
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Cell Death as a Regulator of Cerebellar Histogenesis and Compartmentation. THE CEREBELLUM 2010; 10:373-92. [DOI: 10.1007/s12311-010-0222-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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13
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Synapse elimination in olivo-cerebellar explants occurs during a critical period and leaves an indelible trace in Purkinje cells. Proc Natl Acad Sci U S A 2009; 106:14102-7. [PMID: 19666592 DOI: 10.1073/pnas.0902820106] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During developmental synaptogenesis, the pre- and postsynaptic cells undergo specific interactions that lead to the establishment of the mature circuit. We have studied the roles of the pre- and postsynaptic cells in establishing this mature innervation by using an in vitro model of synaptic development. We describe climbing fiber (CF)-Purkinje cell (PC) synaptogenesis in cultured mouse hindbrain explants and show that synaptic competition occurs during early development in vitro. By manipulating the maturation stage of each of the synaptic partners in a coculture experimental paradigm, we found that multi-innervation does not occur when both synaptic partners are mature and have already experienced synapse elimination; in contrast, mature PCs can be multi-innervated when they have never experienced synapse elimination and/or when CFs are immature. However in these cases, the normal process of synapse elimination is impaired. These results show that CF-synapse elimination occurs only during a PC-dependant critical period and triggers indelible signals that prevent synapse competition in the mature system.
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14
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Sillitoe RV, Joyner AL. Morphology, molecular codes, and circuitry produce the three-dimensional complexity of the cerebellum. Annu Rev Cell Dev Biol 2007; 23:549-77. [PMID: 17506688 DOI: 10.1146/annurev.cellbio.23.090506.123237] [Citation(s) in RCA: 285] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The most noticeable morphological feature of the cerebellum is its folded appearance, whereby fissures separate its anterior-posterior extent into lobules. Each lobule is molecularly coded along the medial-lateral axis by parasagittal stripes of gene expression in one cell type, the Purkinje cells (PCs). Additionally, within each lobule distinct combinations of afferents terminate and supply the cerebellum with synchronized sensory and motor information. Strikingly, afferent terminal fields are organized into parasagittal domains, and this pattern bears a close relationship to PC molecular coding. Thus, cerebellum three-dimensional complexity obeys a basic coordinate system that can be broken down into morphology and molecular coding. In this review, we summarize the sequential stages of cerebellum development that produce its laminar structure, foliation, and molecular organization. We also introduce genes that regulate morphology and molecular coding, and discuss the establishment of topographical circuits within the context of the two coordinate systems. Finally, we discuss how abnormal cerebellar organization may result in neurological disorders like autism.
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Affiliation(s)
- Roy V Sillitoe
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY 10021, USA.
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15
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Vogel MW, Caston J, Yuzaki M, Mariani J. The Lurcher mouse: Fresh insights from an old mutant. Brain Res 2007; 1140:4-18. [PMID: 16412991 DOI: 10.1016/j.brainres.2005.11.086] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Accepted: 11/29/2005] [Indexed: 11/30/2022]
Abstract
The Lurcher mouse was first discovered in 1954 as a spontaneously occurring autosomal dominant mutation that caused the degeneration of virtually all cerebellar Purkinje cells and most olivary neurons and granule cells. More recent molecular studies revealed that Lurcher is a gain of function mutation in the delta2 glutamate receptor (GluRdelta2) that converts an alanine to threonine in the highly conserved third hydrophobic segment of GluRdelta2. The mutation converts the receptor into a constitutively leaky cation channel. The GluRdelta2 receptor is predominantly expressed in cerebellar Purkinje cells and in the heterozygous Lurcher mutant (+/Lc). Purkinje cells die due to the mutation in the GluRdelta2 receptor, while olivary neurons and granule cells degenerate due to the loss of their Purkinje cell targets. The purpose of the review is to provide highlights from 5 decades of research on the Lurcher mutant that have provided insights into the developmental mechanisms that regulate cell number during development, cerebellar pattern formation, cerebellar physiology, and the role of the cerebellum in CNS function.
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Affiliation(s)
- Michael W Vogel
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA.
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16
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Fournier B, Lohof AM, Bower AJ, Mariani J, Sherrard RM. Developmental modifications of olivocerebellar topography: the granuloprival cerebellum reveals multiple routes from the inferior olive. J Comp Neurol 2005; 490:85-97. [PMID: 16041715 DOI: 10.1002/cne.20648] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Correct function of neural circuits depends on highly organized neuronal connections, refined from less precise projections through synaptic elimination, collateral regression, or neuronal death. We examined regressive phenomena that define olivocerebellar topography during maturation from Purkinje cell polyinnervation to monoinnervation. We used bilateral retrograde tracing to determine the source of olivocerebellar afferents to posterior vermis lobules VII-VIII in a model of retained immature Purkinje cell polyinnervation, the granuloprival cerebellum. In controls, labelled neurons were found only in the contralateral inferior olive (ION) clustered in a small ventromedial locus that is congruent with known olivocerebellar topography. In granuloprival animals, olivary labelling appeared more dispersed and was present in homologous ipsilateral regions. Double-labelled neurons were never seen. Retrograde tracing following unilateral olivocerebellar transection in adult granuloprival rats revealed: 1) the origin of the normal (remaining) path projecting through the contralateral inferior peduncle was more localized than in irradiated nonpedunculotomized rats, 2) a small double-crossed path, and 3) a projection that ascends the peduncle ipsilateral to the ION of origin, part of which crosses the midline within the cerebellum. Electrophysiological and immunohistochemical assessment in the neonatal cerebellum revealed that transcommissural paths are not present during development but sprout within the irradiated cerebellum. Therefore, the olivocerebellar projection in the granuloprival rat, as a model of the immature path, shows parasagittal organization similar to that of controls in its normally crossed path but possesses additional abnormal projections. Thus, maturation of olivocerebellar topography involves removal of whole developmental paths to define laterality plus synapse elimination within largely predefined parasagittal zones.
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Affiliation(s)
- Betty Fournier
- Laboratoire Développement et Vieillissement du Système Nerveux, Unité Mixte de Recherche 7102 Neurobiologie des Processus Adaptatifs, Centre National de la Recherche Scientifique et Université Pierre et Marie Curie, Paris 75005, France
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17
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Madalosso SH, Pérez-Villegas EM, Armengol JA. Naturally occurring neuronal death during the postnatal development of Purkinje cells and their precerebellar afferent projections. ACTA ACUST UNITED AC 2005; 49:267-79. [PMID: 16111555 DOI: 10.1016/j.brainresrev.2004.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Revised: 09/23/2004] [Accepted: 10/01/2004] [Indexed: 01/10/2023]
Abstract
Naturally occurring neuronal death plays a substantial developmental role in the building of the neural circuitries. The neuronal death caused by different cerebellar mutations is mostly of an apoptotic nature. Apart from the identity of the intrinsic mechanisms of the mutations, adult cerebellar mutants are a powerful tool to causally study the development of the cerebellar connectivity. Thus, studies on adult cerebellar neuronal cell death occurring in mouse mutants elucidate: (i) the dependence of the postsynaptic neurons on their partners, (ii) the 'en cascade' postsynaptic transneuronal degeneration after target-deprivation, and (iii) the close relationship between the molecular modular organization of the cerebellar cortex and dying Purkinje cells. Neuronal cell death has been extensively studied in developing olivocerebellar system. However, less data are available on the occurrence of naturally occurring neuronal death during the in vivo normal development of the Purkinje cells and the mossy fiber system neurons. The developmental role of neuronal death during the establishment and refinement of the olivocerebellar projection is currently discussed. Moreover, the occurrence of neuronal death during the development of the basilar pontine nuclei and its role in the acquisition of the adult pontocerebellar projection is still poorly understood. In the present review, we correlate the dates of Purkinje cells death with the inferior olivary and basilar pontine neuronal apoptosis, discussing their developmental relationships during the elaboration of the fine-grained maps of the cerebellar afferent connections.
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Affiliation(s)
- Silvia H Madalosso
- Laboratory of Neuroscience, Human Anatomy and Embryology Unit, School of Sports, University Pablo de Olavide, Ctra. Utrera km 1 E-41013 Seville, Spain
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Sotelo C, Chédotal A. Development of the olivocerebellar system: migration and formation of cerebellar maps. PROGRESS IN BRAIN RESEARCH 2005; 148:1-20. [PMID: 15661177 DOI: 10.1016/s0079-6123(04)48001-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Constantino Sotelo
- Cátedra de Neurobiología del Desarrollo Remedios Caro Almela at the Instituto de Neurociencias de la Universidad Miguel Hernández and CSIC San Juan, 03550 Alicante, Spain.
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Grimaldi P, Carletti B, Magrassi L, Rossi F. Fate restriction and developmental potential of cerebellar progenitors. Transplantation studies in the developing CNS. PROGRESS IN BRAIN RESEARCH 2005; 148:57-68. [PMID: 15661181 DOI: 10.1016/s0079-6123(04)48006-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The generation of cell diversity from undifferentiated progenitors is regulated by interdependent mechanisms, including cell intrinsic programs and environmental cues. This interaction can be investigated by means of heterochronic/heterotopic transplantation, which allows to examine the behaviour of precursor cells in an unusual environment. The cerebellum provides an ideal model to study cell specification, because its neurons originate according to a well-defined timetable and they can be are readily recognised by morphological features and specific markers. Cerebellar progenitors transplanted to the embryonic cerebellum develop fully mature cerebellar neurons, which often integrate in the host circuitry in a highly specific manner. In extracerebellar locations, cerebellar progenitors preferentially settle in caudal CNS regions where they exclusively acquire cerebellar identities. By contrast, neocortical precursors preferentially settle in rostral regions and fail to develop hindbrain phenotypes. The phenotypic repertoire generated by transplanted cerebellar progenitors is strictly dependent on their age. Embryonic progenitors originate all mature cerebellar cells, whereas postnatal ones exclusively generate later-born types, such as molecular layer interneurons and granule cells. Together, these observations foster the hypothesis that neural progenitors are first specified towards region-specific phenotypes along the rostro-caudal axis of the neural tube. Thereafter, the developmental potential of progenitor cells is progressively restricted towards later generated types. Such a progressive specification of precursor cells in space and time is stably transmitted to their progeny and it cannot be modified by local cues, when these cells are confronted with heterotopic and/or heterochronic environments.
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Affiliation(s)
- Piercesare Grimaldi
- Department of Neuroscience and Rita Levi Montalcini Centre for Brain Repair, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy
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Narboux-Nême N, Louvi A, Alexandre P, Wassef M. Regionalization of the isthmic and cerebellar primordia. PROGRESS IN BRAIN RESEARCH 2005; 148:29-36. [PMID: 15856550 DOI: 10.1016/s0079-6123(04)48003-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The complex migrations of neurons born in the dorsal neural tube of the isthmic and rhombomere l (rl) domains complicate the delineation of the cerebellar primordium. We show that Purkinje cells (P) are likely generated over a wide territory before gathering in the future cerebellar primordium under the developing external granular layer. Later expansion of the cerebellum over a restricted ependymal domain could rely on mutual interations between P cells and granule cell progenitors (GCP). P are attracted by GCP and in turn stimulate their proliferation, increasing the surface of the developing cortex. At later stages, regionalization of the developing and adult cerebellar cortex can be detected through regional variations in the distribution of several P cell markers. Whether and how the developmental and adult P subtypes are related is still unknown and it is unclear if they delineate the same sets of cerebellar subdivisions. We provide evidence that the early P regionalization is involved in intrinsic patterning of the cerebellar primordium, in particular it relate to the organization of the corticonuclear connection. We propose that the early P regionalization provides a scaffold to the mature P regionalization but that the development of functional afferent connections induces a period of P plasticity during which the early regional identity of P could be remodeled.
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Affiliation(s)
- Nicolas Narboux-Nême
- Régionalisation Nerveuse CNRS/ENS, UMR 8542, Ecole normale supérieure, 46 rue d'Ulm, 75005 Paris, France
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Onodera S, Nitatori T, Hicks TP. Olivary projection from the rostral part of the nucleus of Darkschewitsch in the postnatal rat as revealed through the use of a carbocyanine dye. Brain Res 2004; 1015:194-7. [PMID: 15223386 DOI: 10.1016/j.brainres.2004.04.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2004] [Indexed: 10/26/2022]
Abstract
Using a carbocyanine dye in postnatal rats, we have shown that the rostral part of the nucleus of Darkschewitsch (ND), consisting of a subnucleus of the so-called "area parafascicularlis prerubralis " and excluded from the rat's ND proper, projects ipsilaterally to the rostral part of the medial accessory olive. The present study suggests the existence of a precise topographic organization from subnuclei of the area parafascicularlis prerublaris to subnuclei of the inferior olive.
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Affiliation(s)
- Satoru Onodera
- Department of Anatomy, School of Medicine, Iwate Medical University, Uchimaru 19-1, Morioka 020-8505, Japan.
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Sugihara I, Lohof AM, Letellier M, Mariani J, Sherrard RM. Post-lesion transcommissural growth of olivary climbing fibres creates functional synaptic microzones. Eur J Neurosci 2004; 18:3027-36. [PMID: 14656298 DOI: 10.1111/j.1460-9568.2003.03045.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In the adult mammalian central nervous system, reinnervation and recovery from trauma is limited. During development, however, postlesion plasticity may generate alternate paths, providing models to investigate reinnervating axon-target interactions. After unilateral transection of the neonatal rat olivocerebellar path, axons from the ipsilateral inferior olive grow into the denervated hemicerebellum and develop climbing fibre (CF)-like arbors on Purkinje cells (PCs). However, the synaptic function and extent of PC reinnervation remain unknown. In adult rats pedunculotomized on postnatal day 3 the morphological and electrophysiological properties of reinnervating olivocerebellar axons were studied, using axonal reconstruction and patch-clamp PC recording of CF-induced synaptic currents. Reinnervated PCs displayed normal CF currents, and the frequency of PC reinnervation decreased with increasing laterality. Reinnervating CF arbors were predominantly normal but 6% branched within the molecular layer forming smaller secondary arbors. CFs arose from transcommissural olivary axons, which branched extensively near their target PCs to produce on average 36 CFs, which is six times more than normal. Axons terminating in the hemisphere developed more CFs than those terminating in the vermis. However, the precise parasagittal microzone organization was preserved. Transcommissural axons also branched, although to a lesser extent, to the deep cerebellar nuclei and terminated in a distribution indicative of the olivo-cortico-nuclear circuit. These results show that reinnervating olivocerebellar axons are highly plastic in the cerebellum, compensating anatomically and functionally for early postnatal denervation, and that this reparation obeys precise topographic constraints although axonal plasticity is modified by target (PC or deep nuclear neurons) interactions.
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Affiliation(s)
- Izumi Sugihara
- Department of Systems Neurophysiology, Tokyo Medical and Dental University Graduate School of Medicine, Tokyo, Japan
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23
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Abstract
The object of this review is to assemble much of the literature concerning Purkinje cell death in cerebellar pathology and to relate this to what is now known about the complex topography of the cerebellar cortex. A brief introduction to Purkinje cells, and their regionalization is provided, and then the data on Purkinje cell death in mouse models and, where appropriate, their human counterparts, have been arranged according to several broad categories--naturally-occurring and targeted mutations leading to Purkinje cell death, Purkinje cell death due to toxins, Purkinje cell death in ischemia, Purkinje cell death in infection and in inherited disorders, etc. The data reveal that cerebellar Purkinje cell death is much more topographically complex than is usually appreciated.
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Affiliation(s)
- Justyna R Sarna
- Genes Development Research Group, Department of Cell Biology & Anatomy, Faculty of Medicine, The University of Calgary, 3330 Hospital Drive NW, Calgary, Alta., Canada T2N 4N1
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Abstract
During development, inferior olivary axons cross the floor plate and project from the caudal to the rostral hindbrain, whence they grow into the cerebellar plate. We have investigated the axon guidance signals involved in the formation of this projection in vitro. When the cerebellar plate was grafted ectopically along the margin of the hindbrain in organotypic cultures, inferior olivary axons could pathfind to the ectopic cerebellum, establishing a topographically normal projection. Following rostrocaudal reversal of a region of tissue in the axon pathway between the inferior olive and the cerebellum, olivary axons still navigated towards the cerebellum. Moreover, olivary axons could cross a bridging tissue explant (spinal cord) to reach a cerebellar explant. In collagen gel cultures of inferior olive explants, olivary axon outgrowth increased significantly in the presence of cerebellar explants and axons deflected towards the cerebellar tissue. These results show that the cerebellum is a source of diffusible axon guidance signals for olivary axons. We also found that, in organotypic cultures, olivary axons which had crossed the floor plate showed an increased tendency to respond to cerebellar cues. Taken together, these results indicate that the cerebellum is the source of cues that are chemoattractant and growth-promoting for inferior olivary axons; prior exposure to the floor plate increases responsiveness to these cues.
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Affiliation(s)
- Yan Zhu
- MRC Centre for Developmental Neurobiology, 4th Floor New Hunt's House, King's College London, Guy's Campus, London SE1 1UL, UK
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Maier SE, West JR. Alcohol and nutritional control treatments during neurogenesis in rat brain reduce total neuron number in locus coeruleus, but not in cerebellum or inferior olive. Alcohol 2003; 30:67-74. [PMID: 12878276 DOI: 10.1016/s0741-8329(03)00096-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Although a significant amount of progress has been made during the past two decades in determining the effects of alcohol on brain development, there is still a gap in the literature in terms of when the neurons in the brain are more or less vulnerable to the deleterious effects of alcohol. Using a rat model system, we examined the effect of alcohol on the development of three brain regions after exposure to alcohol only during the period of neurogenesis of each specific region. Our working hypothesis was that all three regions would be equally vulnerable to alcohol-induced reductions in neuron number after exposure during neurogenesis. The Purkinje cells of the cerebellum and the neurons of the locus coeruleus and inferior olive were chosen for examination because of their functional relation to the neuroanatomical circuit for motor coordination and gait, which is disrupted in children exposed to alcohol during gestation. Groups of timed-pregnant Sprague-Dawley rats were administered alcohol or nutritional control substitute daily by gavage during the period of neurogenesis for each region, or they were given no treatments. On postnatal day 10, neuron counts were derived from the three regions of the offspring brains by using stereological cell-counting techniques. The number of neurons in the locus coeruleus was reduced in both the alcohol- and nutritional control-treated groups relative to findings for the normal control group. There was no similar reduction in neuron number in the Purkinje cells of the cerebellum, nor in the neurons of the inferior olive, among the treatment groups. These results demonstrate that the period of neurogenesis is not a uniformly vulnerable period for the three brain regions tested, and the findings support the suggestion of a possible avenue for examining the underlying explanation for why some regions are more vulnerable than other regions during various phases of neuronal development.
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Affiliation(s)
- Susan E Maier
- Human Anatomy and Medical Neurobiology, Room 228 Reynolds Medical Building, College of Medicine, 1114 TAMU, The Texas A&M University System Health Science Center, College Station, TX 77843-1114, USA.
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Zhu Y, Guthrie S. Expression of the ETS transcription factor ER81 in the developing chick and mouse hindbrain. Dev Dyn 2002; 225:365-8. [PMID: 12412022 DOI: 10.1002/dvdy.10166] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
ER81 is an ETS domain-containing transcription factor, which is expressed in various developing tissues and organs of the embryo and in pools of developing spinal motor neurons and proprioceptive sensory neurons. Analysis of mice lacking ER81 function showed that this gene played an important role in the establishment of sensory-motor circuitry in the spinal cord. Here, we investigate the expression pattern of er81 in the hindbrain of both chick and mouse embryos. We find that er81 is expressed in a subpopulation of inferior olive neurons, which send their projections to the caudal cerebellum.
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Affiliation(s)
- Yan Zhu
- MRC Centre for Developmental Neurobiology, King's College, Guy's Campus, London, UK
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27
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Rossi F, Saggiorato C, Strata P. Target-specific innervation of embryonic cerebellar transplants by regenerating olivocerebellar axons in the adult rat. Exp Neurol 2002; 173:205-12. [PMID: 11822884 DOI: 10.1006/exnr.2001.7843] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The reestablishment of topographically organized connections is a necessary prerequisite to obtain a full anatomical repair following brain injury. One system where such an issue can be addressed is the olivocerebellar system, where, normally, clusters of inferior olive neurons project to neurochemically heterogeneous Purkinje cell compartments defined by the expression of cell-specific markers, such as zebrin II. To assess whether adult injured olivocerebellar axons that regenerate into cerebellar transplants are able to establish target-specific innervation of grafted Purkinje cells, we made surgical transections in the white matter of adult rat cerebella and placed solid grafts from the embryonic cerebellar anlage into the lesion site. The transplanted tissue developed highly organized minicerebella, in which Purkinje cells were distributed into distinct clusters of zebrin II-immunopositive or -immunonegative neurons, mimicking the cortical compartments present in the normal adult cerebellum. Olivocerebellar axons, labeled by biotinylated dextran amine tracing, regenerated into the transplants where they formed discrete patches made of several terminal arbors impinging upon Purkinje cell dendrites. Among 401 such climbing fiber patches, 96% exclusively innervated Purkinje cells of either phenotype and stopped at the border of the zebrin II(+/-) Purkinje cell clusters, whereas only 4% were extended across this boundary and innervated both zebrin II-positive and -negative Purkinje cells. The results obtained support the view that the embryonic cerebellar tissue provides target-specific information that can be decoded by ingrowing adult olivocerebellar axons in order to establish appropriate innervation patterns with zebrin II-positive or -negative Purkinje cell compartments.
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Affiliation(s)
- Ferdinando Rossi
- Rita Levi Montalcini Centre for Brain Repair, Department of Neuroscience, University of Turin, Turin, Italy
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28
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Plagge A, Sendtner-Voelderndorff L, Sirim P, Freigang J, Rader C, Sonderegger P, Brümmendorf T. The contactin-related protein FAR-2 defines purkinje cell clusters and labels subpopulations of climbing fibers in the developing cerebellum. Mol Cell Neurosci 2001; 18:91-107. [PMID: 11461156 DOI: 10.1006/mcne.2001.1006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
FAR-2 is a novel neural member of the Ig superfamily, which is related to F11/F3/contactin and axonin-1/TAG-1. This protein is expressed by subpopulations of Purkinje cells in the chicken cerebellum and FAR-2-positive clusters of these neurons alternate with FAR-2-negative clusters in both tangential dimensions of the cerebellar cortex. Furthermore, FAR-2 is also expressed by one type of Purkinje cell afferents, namely, the climbing fibers, and different subpopulations of these axons show distinct levels of FAR-2 expression. Homology modeling using axonin-1 as a template reveals that the four aminoterminal Ig domains of FAR-2 form a compact U-shaped structure, which is likely to contain functionally important ligand-binding sites. FAR-2 is binding to the Ig superfamily protein NgCAM/L1, but not to the related receptor NrCAM, and it is also interacting with the modular ECM protein tenascin-R. These results suggest that FAR-2 may contribute to the formation of somatotopic maps of cerebellar afferents during the development of the nervous system.
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Affiliation(s)
- A Plagge
- Max-Planck-Institute for Developmental Biology, Tübingen, Germany
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Tashiro Y, Miyahara M, Shirasaki R, Okabe M, Heizmann CW, Murakami F. Local nonpermissive and oriented permissive cues guide vestibular axons to the cerebellum. Development 2001; 128:973-81. [PMID: 11222151 DOI: 10.1242/dev.128.6.973] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Information that originates from peripheral sensory organs is conveyed by axons of cephalic sensory cranial ganglia connecting the sensory organs to appropriate central targets in the brain. Thus, the establishment of correct axonal projections by sensory afferents is one of the most important issues in neural development. Previously, we examined the development of the vestibular nerve that originates from the VIIIth ganglion using a flat whole-mount preparation of the rat hindbrain and developed an in vitro, culture preparation that can recapitulate vestibular nerve development (Tashiro, Y., Endo, T., Shirasaki, R., Miyahara, M., Heizmann, C. W. and Murakami, F. (2000) J. Comp. Neurol. 417, 491–500). Both in vivo and in vitro, the ascending branch of the VIIIth ganglion projecting to the cerebellum reaches the base of the cerebellar primordium and starts to splay out towards the rhombic lip, apparently avoiding the ventral metencephalon. We now examine the nature of cues that guide vestibulocerebellar axons by applying various manipulations to the flat whole-mount in vitro preparation. Our observations suggest that local nonpermissive cues and oriented cues play a pivotal role in the guidance of vestibular axons to their central target.
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Affiliation(s)
- Y Tashiro
- Laboratory of Neuroscience, Division of Biophysical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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Chu T, Hullinger H, Schilling K, Oberdick J. Spatial and temporal changes in natural and target deprivation-induced cell death in the mouse inferior olive. JOURNAL OF NEUROBIOLOGY 2000; 43:18-30. [PMID: 10756063 DOI: 10.1002/(sici)1097-4695(200004)43:1<18::aid-neu2>3.0.co;2-c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The survival of inferior olive neurons is dependent on contact with cerebellar Purkinje cells. There is evidence that this dependence changes with time. Because inferior olivary axons, called climbing fibers, already show significant topographical ordering in cerebellar target zones during late embryogenesis in mice, the question arises as to whether olive neurons are dependent on target Purkinje cells for their survival at this early age. To better characterize this issue, inferior olive development was studied in two transgenic mouse mutants, wnt-1 and L7ADT, with embryonic and early postnatal loss of cerebellar target cells, respectively, and compared to that in the well-studied mutant, Lurcher. Morphological criteria as well as quantitative measures of apoptosis were considered in this developmental analysis. Survival of inferior olive neurons is observed to be independent of Purkinje cells throughout embryogenesis, but dependence begins immediately at birth in both wild types and mutants. Thereafter, wild types and mutants show a rapid increase in olive cell apoptosis, with a peak at postnatal day 4, followed by a period of low-level, but significant, apoptosis that continues to at least postnatal day 11; the main difference is that apoptosis is quantitatively enhanced in the mutants compared to wild types. The multiphasic course of these effects roughly parallels the known phases of climbing fiber synaptogenesis. In addition, despite significant temporal differences among the mutants with respect to absolute numbers of dying cells, there are common spatial features suggestive of distinct intrinsic programs linking different olivary subnuclei to their targets.
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Affiliation(s)
- T Chu
- Department of Neuroscience and the Neurobiotechnology Center, The Ohio State University College of Medicine, Columbus, Ohio, USA
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31
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Zagrebelsky M, Rossi F. Postnatal development and adult organisation of the olivocerebellar projection map in the hypogranular cerebellum of the rat. J Comp Neurol 1999; 407:527-42. [PMID: 10235643 DOI: 10.1002/(sici)1096-9861(19990517)407:4<527::aid-cne5>3.0.co;2-h] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The olivocerebellar system is characterised by a precise topographical organisation, in which distinct subsets of inferior olivary axons project to neurochemically heterogeneous Purkinje cell subpopulations, arranged into parasagittally oriented compartments in the cerebellar cortex. Adult climbing fibres and Purkinje cells are linked by a one-to-one relationship, which is established during postnatal development after a transitory phase of multiple climbing fibre innervation. The elimination of redundant climbing fibre synapses is thought to be regulated by granule cell-mediated activity-dependent processes. In order to assess whether this developmental remodelling is also important for the construction of the mature olivocerebellar projection map, we examined the hypogranular cerebella of rats treated by means of methylazoxymethanol acetate (MAM) during early postnatal life, in which multiple climbing fibre innervation persists in the adult. In these animals we investigated the distribution of calcitonin gene-related peptide (CGRP)-immunoreactive olivocerebellar axons and arbours during early postnatal development, and the correspondence between climbing fibre strips and zebrin II-defined Purkinje cell bands in the adult. Our results show that: (1) the pattern of CGRP-immunoreactive climbing fibres observed during the first three postnatal weeks is not disrupted after granule cell degeneration; and (2) the alignment between olivocerebellar axon subsets and zebrin II+/- Purkinje cell compartments is normally achieved in adult rats. In contrast, the climbing fibre-Purkinje cell relationship is abnormal, and single arbours innervate restricted dendritic regions of several neighbouring target neurons. These results indicate that the normal distribution of olivocerebellar axon subsets to distinct cerebellar cortical compartments can be established independently from granule cell-mediated remodelling processes. Thus, the postnatal climbing fibre plasticity, which is needed to achieve the normal climbing fibre-Purkinje cell relationship, appears to be confined within the framework of a projection map established during earlier developmental phases.
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Affiliation(s)
- M Zagrebelsky
- Department of Neuroscience, University of Turin, Italy
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