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Sample records for cerebellar purkinje cell

  1. Cerebellar endocannabinoids: retrograde signaling from purkinje cells.

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    Marcaggi, Païkan

    2015-06-01

    The cerebellar cortex exhibits a strikingly high expression of type 1 cannabinoid receptor (CB1), the cannabinoid binding protein responsible for the psychoactive effects of marijuana. CB1 is primarily found in presynaptic elements in the molecular layer. While the functional importance of cerebellar CB1 is supported by the effect of gene deletion or exogenous cannabinoids on animal behavior, evidence for a role of endocannabinoids in synaptic signaling is provided by in vitro experiments on superfused acute rodent cerebellar slices. These studies have demonstrated that endocannabinoids can be transiently released by Purkinje cells and signal at synapses in a direction opposite to information transfer (retrograde). Here, following a description of the reported expression pattern of the endocannabinoid system in the cerebellum, I review the accumulated in vitro data, which have addressed the mechanism of retrograde endocannabinoid signaling and identified 2-arachidonoylglycerol as the mediator of this signaling. The mechanisms leading to endocannabinoid release, the effects of CB1 activation, and the associated synaptic plasticity mechanisms are discussed and the remaining unknowns are pointed. Notably, it is argued that the spatial specificity of this signaling and the physiological conditions required for its induction need to be determined in order to understand endocannabinoid function in the cerebellar cortex.

  2. Mapping the development of cerebellar Purkinje cells in zebrafish.

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    Hamling, Kyla R; Tobias, Zachary J C; Weissman, Tamily A

    2015-11-01

    The cells that comprise the cerebellum perform a complex integration of neural inputs to influence motor control and coordination. The functioning of this circuit depends upon Purkinje cells and other cerebellar neurons forming in the precise place and time during development. Zebrafish provide a useful platform for modeling disease and studying gene function, thus a quantitative metric of normal zebrafish cerebellar development is key for understanding how gene mutations affect the cerebellum. To begin to quantitatively measure cerebellar development in zebrafish, we have characterized the spatial and temporal patterning of Purkinje cells during the first 2 weeks of development. Differentiated Purkinje cells first emerged by 2.8 days post fertilization and were spatially patterned into separate dorsomedial and ventrolateral clusters that merged at around 4 days. Quantification of the Purkinje cell layer revealed that there was a logarithmic increase in both Purkinje cell number as well as overall volume during the first 2 weeks, while the entire region curved forward in an anterior, then ventral direction. Purkinje cell dendrites were positioned next to parallel fibers as early as 3.3 days, and Purkinje cell diameter decreased significantly from 3.3 to 14 days, possibly due to cytoplasmic reappropriation into maturing dendritic arbors. A nearest neighbor analysis showed that Purkinje cells moved slightly apart from each other from 3 to 14 days, perhaps spreading as the organized monolayer forms. This study establishes a quantitative spatiotemporal map of Purkinje cell development in zebrafish that provides an important metric for studies of cerebellar development and disease.

  3. Remodeling of monoplanar Purkinje cell dendrites during cerebellar circuit formation.

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    Megumi Kaneko

    Full Text Available Dendrite arborization patterns are critical determinants of neuronal connectivity and integration. Planar and highly branched dendrites of the cerebellar Purkinje cell receive specific topographical projections from two major afferent pathways; a single climbing fiber axon from the inferior olive that extend along Purkinje dendrites, and parallel fiber axons of granule cells that contact vertically to the plane of dendrites. It has been believed that murine Purkinje cell dendrites extend in a single parasagittal plane in the molecular layer after the cell polarity is determined during the early postnatal development. By three-dimensional confocal analysis of growing Purkinje cells, we observed that mouse Purkinje cells underwent dynamic dendritic remodeling during circuit maturation in the third postnatal week. After dendrites were polarized and flattened in the early second postnatal week, dendritic arbors gradually expanded in multiple sagittal planes in the molecular layer by intensive growth and branching by the third postnatal week. Dendrites then became confined to a single plane in the fourth postnatal week. Multiplanar Purkinje cells in the third week were often associated by ectopic climbing fibers innervating nearby Purkinje cells in distinct sagittal planes. The mature monoplanar arborization was disrupted in mutant mice with abnormal Purkinje cell connectivity and motor discoordination. The dendrite remodeling was also impaired by pharmacological disruption of normal afferent activity during the second or third postnatal week. Our results suggest that the monoplanar arborization of Purkinje cells is coupled with functional development of the cerebellar circuitry.

  4. Dendritic differentiation of cerebellar Purkinje cells is promoted by ryanodine receptors expressed by Purkinje and granule cells.

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    Ohashi, Ryo; Sakata, Shin-ichi; Naito, Asami; Hirashima, Naohide; Tanaka, Masahiko

    2014-04-01

    Cerebellar Purkinje cells have the most elaborate dendritic trees among neurons in the brain. We examined the roles of ryanodine receptor (RyR), an intracellular Ca(2+) release channel, in the dendrite formation of Purkinje cells using cerebellar cell cultures. In the cerebellum, Purkinje cells express RyR1 and RyR2, whereas granule cells express RyR2. When ryanodine (10 µM), a blocker of RyR, was added to the culture medium, the elongation and branching of Purkinje cell dendrites were markedly inhibited. When we transferred small interfering RNA (siRNA) against RyR1 into Purkinje cells using single-cell electroporation, dendritic branching but not elongation of the electroporated Purkinje cells was inhibited. On the other hand, transfection of RyR2 siRNA into granule cells also inhibited dendritic branching of Purkinje cells. Furthermore, ryanodine reduced the levels of brain-derived neurotrophic factor (BDNF) in the culture medium. The ryanodine-induced inhibition of dendritic differentiation was partially rescued when BDNF was exogenously added to the culture medium in addition to ryanodine. Overall, these results suggest that RyRs expressed by both Purkinje and granule cells play important roles in promoting the dendritic differentiation of Purkinje cells and that RyR2 expressed by granule cells is involved in the secretion of BDNF from granule cells.

  5. Voltage-gated sodium channels in cerebellar Purkinje cells of mormyrid fish

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    M.M. de Ruiter (Martijn); C.I. de Zeeuw (Chris); C.R.W. Hansel (Christian)

    2006-01-01

    textabstractCerebellar Purkinje cells of mormyrid fish differ in some morphological as well as physiological parameters from their counterparts in mammals. Morphologically, Purkinje cells of mormyrids have larger dendrites that are characterized by a lower degree of branching in the molecular layer.

  6. Calcium Imaging Reveals Coordinated Simple Spike Pauses in Populations of Cerebellar Purkinje Cells

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    Jorge E. Ramirez

    2016-12-01

    Full Text Available The brain’s control of movement is thought to involve coordinated activity between cerebellar Purkinje cells. The results reported here demonstrate that somatic Ca2+ imaging is a faithful reporter of Na+-dependent “simple spike” pauses and enables us to optically record changes in firing rates in populations of Purkinje cells in brain slices and in vivo. This simultaneous calcium imaging of populations of Purkinje cells reveals a striking spatial organization of pauses in Purkinje cell activity between neighboring cells. The source of this organization is shown to be the presynaptic gamma-Aminobutyric acid producing (GABAergic network, and blocking ionotropic gamma-Aminobutyric acid receptor (GABAARs abolishes the synchrony. These data suggest that presynaptic interneurons synchronize (inactivity between neighboring Purkinje cells, and thereby maximize their effect on downstream targets in the deep cerebellar nuclei.

  7. Molecular mechanisms governing competitive synaptic wiring in cerebellar Purkinje cells.

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    Watanabe, Masahiko

    2008-03-01

    Cerebellar Purkinje cells (PCs) play a principal role in motor coordination and motor learning. To fulfill these functions, PCs receive and integrate two types of excitatory inputs, climbing fiber (CF) and parallel fiber (PF). CFs are projection axons from the inferior olive, and convey error signals to PCs. On the other hand, PFs are T-shaped axons of cerebellar granule cells, and convey sensory and motor information carried through the pontocerebellar and spinocerebellar mossy fiber pathways. The most remarkable feature of PC circuits is the highly territorial innervation by these two excitatory afferents. A single climbing CF powerfully and exclusively innervates proximal PC dendrites, whereas hundreds of thousands of PFs innervate distal PC dendrites. Recent studies using gene-manipulated mice have been elucidating that the PC circuitry is formed and maintained by molecular mechanisms that fuel homosynaptic competition among CFs and heterosynaptic competition between CFs and PFs. GluRdelta2 (a PC-specific glutamate receptor) and precerebellin or Cbln1 (a granule cell-derived secretory protein) cooperatively work for selective strengthening of PF-PC synapses, and prevent excessive distal extension of CFs that eventually causes multiple innervation at distal dendrites. In contrast, P/Q-type Ca2+ channels, which mediate Ca2+ influx upon CF activity, selectively strengthen the innervation by a single main CF, and expel PFs and other CFs from proximal dendrites that it innervates. Therefore, we now understand that owing to these mechanisms, territorial innervation by CFs and PFs is properly structured and mono-innervation by CFs is established. Several key issues for future study are also discussed.

  8. Optogenetics in the cerebellum: Purkinje cell-specific approaches for understanding local cerebellar functions.

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    Tsubota, Tadashi; Ohashi, Yohei; Tamura, Keita

    2013-10-15

    The cerebellum consists of the cerebellar cortex and the cerebellar nuclei. Although the basic neuronal circuitry of the cerebellar cortex is uniform everywhere, anatomical data demonstrate that the input and output relationships of the cortex are spatially segregated between different cortical areas, which suggests that there are functional distinctions between these different areas. Perturbation of cerebellar cortical functions in a spatially restricted fashion is thus essential for investigating the distinctions among different cortical areas. In the cerebellar cortex, Purkinje cells are the sole output neurons that send information to downstream cerebellar and vestibular nuclei. Therefore, selective manipulation of Purkinje cell activities, without disturbing other neuronal types and passing fibers within the cortex, is a direct approach to spatially restrict the effects of perturbations. Although this type of approach has for many years been technically difficult, recent advances in optogenetics now enable selective activation or inhibition of Purkinje cell activities, with high temporal resolution. Here we discuss the effectiveness of using Purkinje cell-specific optogenetic approaches to elucidate the functions of local cerebellar cortex regions. We also discuss what improvements to current methods are necessary for future investigations of cerebellar functions to provide further advances.

  9. Cerebellar Purkinje cells incorporate immunoglobulins and immunotoxins in vitro: implications for human neurological disease and immunotherapeutics

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    Rose John W

    2009-10-01

    Full Text Available Abstract Background Immunoglobulin G (IgG antibodies reactive with intracellular neuronal proteins have been described in paraneoplastic and other autoimmune disorders. Because neurons have been thought impermeable to immunoglobulins, however, such antibodies have been considered unable to enter neurons and bind to their specific antigens during life. Cerebellar Purkinje cells - an important target in paraneoplastic and other autoimmune diseases - have been shown in experimental animals to incorporate a number of molecules from cerebrospinal fluid. IgG has also been detected in Purkinje cells studied post mortem. Despite the possible significance of these findings for human disease, immunoglobulin uptake by Purkinje cells has not been demonstrated in living tissue or studied systematically. Methods To assess Purkinje cell uptake of immunoglobulins, organotypic cultures of rat cerebellum incubated with rat IgGs, human IgG, fluorescein-conjugated IgG, and rat IgM were studied by confocal microscopy in real time and following fixation. An IgG-daunorubicin immunotoxin was used to determine whether conjugation of pharmacological agents to IgG could be used to achieve Purkinje cell-specific drug delivery. Results IgG uptake was detected in Purkinje cell processes after 4 hours of incubation and in Purkinje cell cytoplasm and nuclei by 24-48 hours. Uptake could be followed in real time using IgG-fluorochrome conjugates. Purkinje cells also incorporated IgM. Intracellular immunoglobulin did not affect Purkinje cell viability, and Purkinje cells cleared intracellular IgG or IgM within 24-48 hours after transfer to media lacking immunoglobulins. The IgG-daunomycin immunotoxin was also rapidly incorporated into Purkinje cells and caused extensive, cell-specific death within 8 hours. Purkinje cell death was not produced by unconjugated daunorubicin or control IgG. Conclusion Purkinje cells in rat organotypic cultures incorporate and clear host (rat and non

  10. Axonal abnormalities in cerebellar Purkinje cells of the Ts65Dn mouse.

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    Necchi, Daniela; Lomoio, Selene; Scherini, Elda

    2008-10-31

    Ts65Dn mice are a genetic model for Down syndrome. Among others, these mice have cerebellar pathology features which parallel those seen in Down syndrome patients. Both individuals with Down syndrome and Ts65Dn mice have reduced cerebellar volume and numbers of granule and Purkinje cells. In this report, we describe morphological abnormalities of axons of Purkinje cells in the cerebellum of Ts65Dn mice, by using anti-calbindin immunocytochemistry. A consistent number of Purkinje cells shows axons bearing giant varicosities along their transit through the granular layer. The cerebellar arbor vitae made by fasciculated Purkinje cell axons has a patchy appearance, some tracks being devoid of calbindin staining. The infraganglionic plexus, formed by recurrent collaterals of Purkinje cell axons, has enormously increased density, which is evidence for a compensatory reaction to degeneration of distal segments of axons. These alterations are accompanied by strong glial reaction as evidenced by GFAP immunocytochemistry. Moreover, the alterations are more consistent in the anterior lobules of the vermis and intermediate cortex. The axonal pathology of Purkinje cells may explain the impairment in cerebellar functions observed in Ts65Dn mice at the adulthood.

  11. Purkinje cell activity in the cerebellar anterior lobe after rabbit eyeblink conditioning

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    Green, John T.; Steinmetz, Joseph E.

    2005-01-01

    The cerebellar anterior lobe may play a critical role in the execution and proper timing of learned responses. The current study was designed to monitor Purkinje cell activity in the rabbit cerebellar anterior lobe after eyeblink conditioning, and to assess whether Purkinje cells in recording locations may project to the interpositus nucleus. Rabbits were trained in an interstimulus interval discrimination procedure in which one tone signaled a 250-msec conditioned stimulus-unconditioned stimulus (CS-US) interval and a second tone signaled a 750-msec CS-US interval. All rabbits showed conditioned responses to each CS with mean onset and peak latencies that coincided with the CS-US interval. Many anterior lobe Purkinje cells showed significant learning-related activity after eyeblink conditioning to one or both of the CSs. More Purkinje cells responded with inhibition than with excitation to CS presentation. In addition, when the firing patterns of all conditioning-related Purkinje cells were pooled, it appeared that the population showed a pattern of excitation followed by inhibition during the CS-US interval. Using cholera toxin-conjugated horseradish peroxidase, Purkinje cells in recording areas were found to project to the interpositus nucleus. These data support previous studies that have suggested a role for the anterior cerebellar cortex in eyeblink conditioning as well as models of cerebellar-mediated CR timing that postulate that Purkinje cell activity inhibits conditioned response (CR) generation during the early portion of a trial by inhibiting the deep cerebellar nuclei and permits CR generation during the later portion of a trial through disinhibition of the cerebellar nuclei. PMID:15897252

  12. Atypical protein kinase C regulates primary dendrite specification of cerebellar Purkinje cells by localizing Golgi apparatus.

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    Tanabe, Koji; Kani, Shuichi; Shimizu, Takashi; Bae, Young-Ki; Abe, Takaya; Hibi, Masahiko

    2010-12-15

    Neurons have highly polarized structures that determine what parts of the soma elaborate the axon and dendrites. However, little is known about the mechanisms that establish neuronal polarity in vivo. Cerebellar Purkinje cells extend a single primary dendrite from the soma that ramifies into a highly branched dendritic arbor. We used the zebrafish cerebellum to investigate the mechanisms by which Purkinje cells acquire these characteristics. To examine dendritic morphogenesis in individual Purkinje cells, we marked the cell membrane using a Purkinje cell-specific promoter to drive membrane-targeted fluorescent proteins. We found that zebrafish Purkinje cells initially extend multiple neurites from the soma and subsequently retract all but one, which becomes the primary dendrite. In addition, the Golgi apparatus specifically locates to the root of the primary dendrite, and its localization is already established in immature Purkinje cells that have multiple neurites. Inhibiting secretory trafficking through the Golgi apparatus reduces dendritic growth, suggesting that the Golgi apparatus is involved in the dendritic morphogenesis. We also demonstrated that in a mutant of an atypical protein kinase C (aPKC), Prkci, Purkinje cells retain multiple primary dendrites and show disrupted localization of the Golgi apparatus. Furthermore, a mosaic inhibition of Prkci in Purkinje cells recapitulates the aPKC mutant phenotype. These results suggest that the aPKC cell autonomously controls the Golgi localization and thereby regulates the specification of the primary dendrite of Purkinje cells.

  13. Purkinje cell heterotopy with cerebellar hypoplasia in two free-living American kestrels (Falco sparverius).

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    Armién, A G; McRuer, D L; Ruder, M G; Wünschmann, A

    2013-01-01

    Two wild fledgling kestrels exhibited lack of motor coordination, postural reaction deficits, and abnormal propioception. At necropsy, the cerebellum and brainstem were markedly underdeveloped. Microscopically, there was Purkinje cells heterotopy, abnormal circuitry, and hypoplasia with defective foliation. Heterotopic neurons were identified as immature Purkinje cells by their size, location, immunoreactivity for calbindin D-28 K, and ultrastructural features. The authors suggest that this cerebellar abnormality was likely due to a disruption of molecular mechanisms that dictate Purkinje cell migration, placement, and maturation in early embryonic development. The etiology of this condition remains undetermined. Congenital central nervous system disorders have rarely been reported in birds.

  14. Fear conditioning-related changes in cerebellar Purkinje cell activities in goldfish

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    Yoshida Masayuki

    2012-10-01

    Full Text Available Abstract Background Fear conditioning-induced changes in cerebellar Purkinje cell responses to a conditioned stimulus have been reported in rabbits. It has been suggested that synaptic long-term potentiation and the resulting increases in firing rates of Purkinje cells are related to the acquisition of conditioned fear in mammals. However, Purkinje cell activities during acquisition of conditioned fear have not been analysed, and changes in Purkinje cell activities throughout the development of conditioned fear have not yet been investigated. In the present study, we tracked Purkinje cell activities throughout a fear conditioning procedure and aimed to elucidate further how cerebellar circuits function during the acquisition and expression of conditioned fear. Methods Activities of single Purkinje cells in the corpus cerebelli were tracked throughout a classical fear conditioning procedure in goldfish. A delayed conditioning paradigm was used with cardiac deceleration as the conditioned response. Conditioning-related changes of Purkinje cell responses to a conditioned stimulus and unconditioned stimulus were examined. Results The majority of Purkinje cells sampled responded to the conditioned stimulus by either increasing or decreasing their firing rates before training. Although there were various types of conditioning-related changes in Purkinje cells, more than half of the cells showed suppressed activities in response to the conditioned stimulus after acquisition of conditioned fear. Purkinje cells that showed unconditioned stimulus-coupled complex-spike firings also exhibited conditioning-related suppression of simple-spike responses to the conditioned stimulus. A small number of Purkinje cells showed increased excitatory responses in the acquisition sessions. We found that the magnitudes of changes in the firing frequencies of some Purkinje cells in response to the conditioned stimulus correlated with the magnitudes of the conditioned

  15. Cbln1 downregulates the formation and function of inhibitory synapses in mouse cerebellar Purkinje cells.

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    Ito-Ishida, Aya; Kakegawa, Wataru; Kohda, Kazuhisa; Miura, Eriko; Okabe, Shigeo; Yuzaki, Michisuke

    2014-04-01

    The formation of excitatory and inhibitory synapses must be tightly coordinated to establish functional neuronal circuitry during development. In the cerebellum, the formation of excitatory synapses between parallel fibers and Purkinje cells is strongly induced by Cbln1, which is released from parallel fibers and binds to the postsynaptic δ2 glutamate receptor (GluD2). However, Cbln1's role, if any, in inhibitory synapse formation has been unknown. Here, we show that Cbln1 downregulates the formation and function of inhibitory synapses between Purkinje cells and interneurons. Immunohistochemical analyses with an anti-vesicular GABA transporter antibody revealed an increased density of interneuron-Purkinje cell synapses in the cbln1-null cerebellum. Whole-cell patch-clamp recordings from Purkinje cells showed that both the amplitude and frequency of miniature inhibitory postsynaptic currents were increased in cbln1-null cerebellar slices. A 3-h incubation with recombinant Cbln1 reversed the increased amplitude of inhibitory currents in Purkinje cells in acutely prepared cbln1-null slices. Furthermore, an 8-day incubation with recombinant Cbln1 reversed the increased interneuron-Purkinje cell synapse density in cultured cbln1-null slices. In contrast, recombinant Cbln1 did not affect cerebellar slices from mice lacking both Cbln1 and GluD2. Finally, we found that tyrosine phosphorylation was upregulated in the cbln1-null cerebellum, and acute inhibition of Src-family kinases suppressed the increased inhibitory postsynaptic currents in cbln1-null Purkinje cells. These findings indicate that Cbln1-GluD2 signaling inhibits the number and function of inhibitory synapses, and shifts the excitatory-inhibitory balance towards excitation in Purkinje cells. Cbln1's effect on inhibitory synaptic transmission is probably mediated by a tyrosine kinase pathway.

  16. Role of synchronous activation of cerebellar purkinje cell ensembles in multi-joint movement control

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    T.M. Hoogland (Tycho); J.R. de Gruijl (Jornt); L. Witter (Laurens); M.I. Canto (Marcia Irene); C.I. de Zeeuw (Chris)

    2015-01-01

    textabstractIt is a longstanding question in neuroscience how elaborate multi-joint movements are coordinated coherently. Microzones of cerebellar Purkinje cells (PCs) are thought to mediate this coordination by controlling the timing of particular motor domains. However, it remains to be elucidated

  17. Role of Synchronous Activation of Cerebellar Purkinje Cell Ensembles in Multi-joint Movement Control

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    Hoogland, Tycho M; De Gruijl, Jornt R; Witter, Laurens; Canto, Cathrin B; De Zeeuw, Chris I

    2015-01-01

    It is a longstanding question in neuroscience how elaborate multi-joint movements are coordinated coherently. Microzones of cerebellar Purkinje cells (PCs) are thought to mediate this coordination by controlling the timing of particular motor domains. However, it remains to be elucidated to what ext

  18. [Mathematical simulation of induction of long-term depression in cerebellar Purkinje cells].

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    Murzina, G B

    2003-01-01

    Mechanisms of associative and homosynaptic long-term depression (LTD) in cerebellar Purkinje cells are discussed. The possibility of LTD induction related to a decrease in efficacy of AMPA receptors through either their dephosphorylation or phosphorylation is investigated by mathematical simulation.

  19. Mathematical simulation of the induction of long-term depression in cerebellar Purkinje cells.

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    Murzina, G B

    2004-02-01

    The question of the mechanisms underlying the induction of associative and homosynaptic long-term depression in cerebellar Purkinje cells is addressed. Mathematical simulation was used to investigate the possibility that long-term depression, which is associated with a decrease in the efficiency of AMPA receptors, could be induced both by phosphorylation and dephosphorylation of these receptors.

  20. An improved method for culturing cerebellar Purkinje cells with differentiated dendrites under a mixed monolayer setting.

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    Furuya, S; Makino, A; Hirabayashi, Y

    1998-11-01

    We report here a novel cell culture protocol which facilitates in vitro survival and dendritic differentiation of cerebellar Purkinje cells in a monolayer, mixed culture setting. We found that the type of culture medium is a critical factor for the maintenance of these cells. Purkinje cells present in the single cell suspension of embryonic rat cerebellum were best maintained in a medium based on Dulbecco's modified Eagle's medium (DMEM)/F-12 without the addition of known neurotrophic factors. These cells maintained in DMEM/F-12-based media displayed an approximately 2.5-3.5-fold increase in survival compared with cells maintained in the widely used Basal Medium Eagle's (BME)-based serum-free culture medium with the same supplements. This novel protocol permits not only enhanced survival but also accelerated, improved dendritic differentiation of these cells. Purkinje cells developed highly branched spiny dendrites by 14-16 days in vitro, which matches the time course of the dendritic growth of these cells in vivo. The Purkinje cells expressed metabotropic glutamate receptor 1alpha in the cell bodies and branched dendrites, and the intradendritic calcium concentration increased when trans-ACPD, a selective agonist of this receptor, was applied. This novel protocol allows the development of functional branched dendrites and therefore is useful for electrophysiological and ion-imaging studies on dendrites of Purkinje cells grown in vitro.

  1. Properties and expression of Kv3 channels in cerebellar Purkinje cells.

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    Sacco, Tiziana; De Luca, Annarita; Tempia, Filippo

    2006-10-01

    In cerebellar Purkinje cells, Kv3 potassium channels are indispensable for firing at high frequencies. In Purkinje cells from young mice (P4-P7), Kv3 currents, recorded in whole-cell in slices, activated at -30 mV, with rapid activation and deactivation kinetics, and they were partially blocked by blood depressing substance-I (BDS-I, 1 microM). At positive potentials, Kv3 currents were slowly but completely inactivating, while the recovery from inactivation was about eightfold slower, suggesting that a previous firing activity or a small change of the resting potential could in principle accumulate inactivated Kv3 channels, thereby finely tuning Kv3 current availability for subsequent action potentials. Single-cell RT-PCR analysis showed the expression by all Purkinje cells (n=10 for each subunit) of Kv3.1, Kv3.3 and Kv3.4 mRNA, while Kv3.2 was not expressed. These results add to the framework for interpreting the physiological function and the molecular determinants of Kv3 currents in cerebellar Purkinje cells.

  2. Regulation and functional roles of rebound potentiation at cerebellar stellate cell - Purkinje cell synapses

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    Tomoo eHirano

    2014-02-01

    Full Text Available Purkinje cells receive both excitatory and inhibitory synaptic inputs and send sole output from the cerebellar cortex. Long-term depression, a type of synaptic plasticity, at excitatory parallel fiber–Purkinje cell synapses has been studied extensively as a primary cellular mechanism of motor learning. On the other hand, at inhibitory synapses on a Purkinje cell, postsynaptic depolarization induces long-lasting potentiation of GABAergic synaptic transmission. This synaptic plasticity is called rebound potentiation (RP, and its molecular regulatory mechanisms have been studied. The increase in intracellular Ca2+ concentration caused by depolarization induces RP through enhancement of GABAA receptor (GABAAR responsiveness. RP induction depends on binding of GABAAR with GABAAR associated protein (GABARAP which is regulated by Ca2+/calmodulin-dependent kinase II (CaMKII. Whether RP is induced or not is determined by the balance between phosphorylation and de-phosphorylation activities regulated by intracellular Ca2+ and by metabotropic GABA and glutamate receptors. Recent studies have revealed that the subunit composition of CaMKII has significant impact on RP induction. A Purkinje cell expresses both alpha- and beta-CaMKII, and the latter has much higher affinity for Ca2+/calmodulin than the former. It was shown that when the relative amount of alpha- to beta-CaMKII is large, RP induction is suppressed. The functional significance of RP has also been studied using transgenic mice in which a peptide inhibiting association of GABARAP and GABAAR is expressed selectively in Purkinje cells. The transgenic mice show abrogation of RP and subnormal adaptation of vestibulo-ocular reflex, a type of motor learning. Thus, RP is involved in a certain type of motor learning.

  3. Climbing fiber synapse elimination in cerebellar Purkinje cells.

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    Watanabe, Masahiko; Kano, Masanobu

    2011-11-01

    Innervation of Purkinje cells (PCs) by multiple climbing fibers (CFs) is refined into mono-innervation during the first three postnatal weeks of rodents' lives. In this review article, we will integrate the current knowledge on developmental process and mechanisms of CF synapse elimination. In the 'creeper' stage of CF innervation (postnatal day 0 (P0)∼), CFs creep among PC somata to form transient synapses on immature dendrites. In the 'pericellular nest' stage (P5∼), CFs densely surround and innervate PC somata. CF innervation is then displaced to the apical portion of PC somata in the 'capuchon' stage (P9∼), and translocate to dendrites in the 'dendritic' (P12∼) stage. Along with the developmental changes in CF wiring, functional and morphological distinctions become larger among CF inputs. PCs are initially innervated by more than five CFs with similar strengths (∼P3). During P3-7 only a single CF is selectively strengthened (functional differentiation), and it undergoes dendritic translocation from P9 on (dendritic translocation). Following the functional differentiation, perisomatic CF synapses are eliminated nonselectively; this proceeds in two distinct phases. The early phase (P7-11) is conducted independently of parallel fiber (PF)-PC synapse formation, while the late phase (P12-17) critically depends on it. The P/Q-type voltage-dependent Ca(2+) channel in PCs triggers selective strengthening of single CF inputs, promotes dendritic translocation of the strengthened CFs, and drives the early phase of CF synapse elimination. In contrast, the late phase is mediated by the mGluR1-Gαq-PLCβ4-PKCγ signaling cascade in PCs driven at PF-PC synapses, whose structural connectivity is stabilized and maintained by the GluRδ2-Cbln1-neurexin system.

  4. Acid-sensitive channel inhibition prevents fetal alcohol spectrum disorders cerebellar Purkinje cell loss.

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    Ramadoss, Jayanth; Lunde, Emilie R; Ouyang, Nengtai; Chen, Wei-Jung A; Cudd, Timothy A

    2008-08-01

    Ethanol is now considered the most common human teratogen. Educational campaigns have not reduced the incidence of ethanol-mediated teratogenesis, leading to a growing interest in the development of therapeutic prevention or mitigation strategies. On the basis of the observation that maternal ethanol consumption reduces maternal and fetal pH, we hypothesized that a pH-sensitive pathway involving the TWIK-related acid-sensitive potassium channels (TASKs) is implicated in ethanol-induced injury to the fetal cerebellum, one of the most sensitive targets of prenatal ethanol exposure. Pregnant ewes were intravenously infused with ethanol (258+/-10 mg/dl peak blood ethanol concentration) or saline in a "3 days/wk binge" pattern throughout the third trimester. Quantitative stereological analysis demonstrated that ethanol resulted in a 45% reduction in the total number of fetal cerebellar Purkinje cells, the cell type most sensitive to developmental ethanol exposure. Extracellular pH manipulation to create the same degree and pattern of pH fall caused by ethanol (manipulations large enough to inhibit TASK 1 channels), resulted in a 24% decrease in Purkinje cell number. We determined immunohistochemically that TASK 1 channels are expressed in Purkinje cells and that the TASK 3 isoform is expressed in granule cells of the ovine fetal cerebellum. Pharmacological blockade of both TASK 1 and TASK 3 channels simultaneous with ethanol effectively prevented any reduction in fetal cerebellar Purkinje cell number. These results demonstrate for the first time functional significance of fetal cerebellar two-pore domain pH-sensitive channels and establishes them as a potential therapeutic target for prevention of ethanol teratogenesis.

  5. Alcohol Impairs Long-Term Depression at the Cerebellar Parallel Fiber–Purkinje Cell Synapse

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    Belmeguenai, Amor; Botta, Paolo; Weber, John T.; Carta, Mario; De Ruiter, Martijn; De Zeeuw, Chris I.; Valenzuela, C. Fernando; Hansel, Christian

    2008-01-01

    Acute alcohol consumption causes deficits in motor coordination and gait, suggesting an involvement of cerebellar circuits, which play a role in the fine adjustment of movements and in motor learning. It has previously been shown that ethanol modulates inhibitory transmission in the cerebellum and affects synaptic transmission and plasticity at excitatory climbing fiber (CF) to Purkinje cell synapses. However, it has not been examined thus far how acute ethanol application affects long-term depression (LTD) and long-term potentiation (LTP) at excitatory parallel fiber (PF) to Purkinje cell synapses, which are assumed to mediate forms of cerebellar motor learning. To examine ethanol effects on PF synaptic transmission and plasticity, we performed whole cell patch-clamp recordings from Purkinje cells in rat cerebellar slices. We found that ethanol (50 mM) selectively blocked PF–LTD induction, whereas it did not change the amplitude of excitatory postsynaptic currents at PF synapses. In contrast, ethanol application reduced voltage-gated calcium currents and type 1 metabotropic glutamate receptor (mGluR1)–dependent responses in Purkinje cells, both of which are involved in PF–LTD induction. The selectivity of these effects is emphasized by the observation that ethanol did not impair PF–LTP and that PF–LTP could readily be induced in the presence of the group I mGluR antagonist AIDA or the mGluR1a antagonist LY367385. Taken together, these findings identify calcium currents and mGluR1-dependent signaling pathways as potential ethanol targets and suggest that an ethanol-induced blockade of PF–LTD could contribute to the motor coordination deficits resulting from alcohol consumption. PMID:18922952

  6. Mitochondrial fission protein Drp1 regulates mitochondrial transport and dendritic arborization in cerebellar Purkinje cells.

    Science.gov (United States)

    Fukumitsu, Kansai; Hatsukano, Tetsu; Yoshimura, Azumi; Heuser, John; Fujishima, Kazuto; Kengaku, Mineko

    2016-03-01

    Mitochondria dynamically change their shape by repeated fission and fusion in response to physiological and pathological conditions. Recent studies have uncovered significant roles of mitochondrial fission and fusion in neuronal functions, such as neurotransmission and spine formation. However, the contribution of mitochondrial fission to the development of dendrites remains controversial. We analyzed the function of the mitochondrial fission GTPase Drp1 in dendritic arborization in cerebellar Purkinje cells. Overexpression of a dominant-negative mutant of Drp1 in postmitotic Purkinje cells enlarged and clustered mitochondria, which failed to exit from the soma into the dendrites. The emerging dendrites lacking mitochondrial transport remained short and unstable in culture and in vivo. The dominant-negative Drp1 affected neither the basal respiratory function of mitochondria nor the survival of Purkinje cells. Enhanced ATP supply by creatine treatment, but not reduced ROS production by antioxidant treatment, restored the hypomorphic dendrites caused by inhibition of Drp1 function. Collectively, our results suggest that Drp1 is required for dendritic distribution of mitochondria and thereby regulates energy supply in growing dendritic branches in developing Purkinje cells.

  7. A new Purkinje cell antibody (anti-Ca associated with subacute cerebellar ataxia: immunological characterization

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    Horn Sigrun

    2010-03-01

    Full Text Available Abstract We report on a newly discovered serum and cerebrospinal fluid (CSF reactivity to Purkinje cells (PCs associated with subacute inflammatory cerebellar ataxia. The patient, a previously healthy 33-year-old lady, presented with severe limb and gait ataxia, dysarthria, and diplopia two weeks after she had recovered from a common cold. Immunohistochemical studies on mouse, rat, and monkey brain sections revealed binding of a high-titer (up to 1:10,000 IgG antibody to the cerebellar molecular layer, Purkinje cell (PC layer, and white matter. The antibody is highly specific for PCs and binds to the cytoplasm as well as to the inner side of the membrane of PC somata, dendrites and axons. It is produced by B cell clones within the CNS, belongs to the IgG1 subclass, and activates complement in vitro. Western blotting of primate cerebellum extract revealed binding of CSF and serum IgG to an 80-97 kDa protein. Extensive control studies were performed to rule out a broad panel of previously described paraneoplastic and non-paraneoplastic antibodies known to be associated with cerebellar ataxia. Screening of >9000 human full length proteins by means of a protein array and additional confirmatory experiments revealed Rho GTPase activating protein 26 (ARHGAP26, GRAF, oligophrenin-1-like protein as the target antigen. Preadsorption of the patient's serum with human ARHGAP26 but not preadsorption with other proteins resulted in complete loss of PC staining. Our findings suggest a role of autoimmunity against ARHGAP26 in the pathogenesis of subacute inflammatory cerebellar ataxia, and extend the panel of diagnostic markers for this devastating disease.

  8. SK2 channel modulation contributes to compartment-specific dendritic plasticity in cerebellar Purkinje cells.

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    Ohtsuki, Gen; Piochon, Claire; Adelman, John P; Hansel, Christian

    2012-07-12

    Small-conductance Ca(2+)-activated K(+) channels (SK channels) modulate excitability and curtail excitatory postsynaptic potentials (EPSPs) in neuronal dendrites. Here, we demonstrate long-lasting plasticity of intrinsic excitability (IE) in dendrites that results from changes in the gain of this regulatory mechanism. Using dendritic patch-clamp recordings from rat cerebellar Purkinje cells, we find that somatic depolarization or parallel fiber (PF) burst stimulation induce long-term amplification of synaptic responses to climbing fiber (CF) or PF stimulation and enhance the amplitude of passively propagated sodium spikes. Dendritic plasticity is mimicked and occluded by the SK channel blocker apamin and is absent in Purkinje cells from SK2 null mice. Triple-patch recordings from two dendritic sites and the soma and confocal calcium imaging studies show that local stimulation limits dendritic plasticity to the activated compartment of the dendrite. This plasticity mechanism allows Purkinje cells to adjust the SK2-mediated control of dendritic excitability in an activity-dependent manner.

  9. Kv3 K+ channels enable burst output in rat cerebellar Purkinje cells.

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    McKay, B E; Turner, R W

    2004-08-01

    The ability of cells to generate an appropriate spike output depends on a balance between membrane depolarizations and the repolarizing actions of K(+) currents. The high-voltage-activated Kv3 class of K(+) channels repolarizes Na(+) spikes to maintain high frequencies of discharge. However, little is known of the ability for these K(+) channels to shape Ca(2+) spike discharge or their ability to regulate Ca(2+) spike-dependent burst output. Here we identify the role of Kv3 K(+) channels in the regulation of Na(+) and Ca(2+) spike discharge, as well as burst output, using somatic and dendritic recordings in rat cerebellar Purkinje cells. Kv3 currents pharmacologically isolated in outside-out somatic membrane patches accounted for approximately 40% of the total K(+) current, were very fast and high voltage activating, and required more than 1 s to fully inactivate. Kv3 currents were differentiated from other tetraethylammonium-sensitive currents to establish their role in Purkinje cells under physiological conditions with current-clamp recordings. Dual somatic-dendritic recordings indicated that Kv3 channels repolarize Na(+) and Ca(2+) spikes, enabling high-frequency discharge for both types of cell output. We further show that during burst output Kv3 channels act together with large-conductance Ca(2+)-activated K(+) channels to ensure an effective coupling between Ca(2+) and Na(+) spike discharge by preventing Na(+) spike inactivation. By contributing significantly to the repolarization of Na(+) and especially Ca(2+) spikes, our data reveal a novel function for Kv3 K(+) channels in the maintenance of high-frequency burst output for cerebellar Purkinje cells.

  10. A note on the definition and the development of cerebellar purkinje cell zones

    NARCIS (Netherlands)

    J. Voogd (Jan)

    2012-01-01

    textabstractThe definition of Purkinje cell zones by their white matter comprtments, their physiological properties, and their molecular identity and the birthdate of their Purkinje cells will be reviewed.

  11. A spiking network model of cerebellar Purkinje cells and molecular layer interneurons exhibiting irregular firing

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    William eLennon

    2014-12-01

    Full Text Available While the anatomy of the cerebellar microcircuit is well studied, how it implements cerebellar function is not understood. A number of models have been proposed to describe this mechanism but few emphasize the role of the vast network Purkinje cells (PKJs form with the molecular layer interneurons (MLIs – the stellate and basket cells. We propose a model of the MLI-PKJ network composed of simple spiking neurons incorporating the major anatomical and physiological features. In computer simulations, the model reproduces the irregular firing patterns observed in PKJs and MLIs in vitro and a shift toward faster, more regular firing patterns when inhibitory synaptic currents are blocked. In the model, the time between PKJ spikes is shown to be proportional to the amount of feedforward inhibition from an MLI on average. The two key elements of the model are: (1 spontaneously active PKJs and MLIs due to an endogenous depolarizing current, and (2 adherence to known anatomical connectivity along a parasagittal strip of cerebellar cortex. We propose this model to extend previous spiking network models of the cerebellum and for further computational investigation into the role of irregular firing and MLIs in cerebellar learning and function.

  12. Purkinje cell-specific ablation of Cav2.1 channels is sufficient to cause cerebellar ataxia in mice.

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    Todorov, Boyan; Kros, Lieke; Shyti, Reinald; Plak, Petra; Haasdijk, Elize D; Raike, Robert S; Frants, Rune R; Hess, Ellen J; Hoebeek, Freek E; De Zeeuw, Chris I; van den Maagdenberg, Arn M J M

    2012-03-01

    The Cacna1a gene encodes the α(1A) subunit of voltage-gated Ca(V)2.1 Ca(2+) channels that are involved in neurotransmission at central synapses. Ca(V)2.1-α(1)-knockout (α1KO) mice, which lack Ca(V)2.1 channels in all neurons, have a very severe phenotype of cerebellar ataxia and dystonia, and usually die around postnatal day 20. This early lethality, combined with the wide expression of Ca(V)2.1 channels throughout the cerebellar cortex and nuclei, prohibited determination of the contribution of particular cerebellar cell types to the development of the severe neurobiological phenotype in Cacna1a mutant mice. Here, we crossed conditional Cacna1a mice with transgenic mice expressing Cre recombinase, driven by the Purkinje cell-specific Pcp2 promoter, to specifically ablate the Ca(V)2.1-α(1A) subunit and thereby Ca(V)2.1 channels in Purkinje cells. Purkinje cell Ca(V)2.1-α(1A)-knockout (PCα1KO) mice aged without difficulties, rescuing the lethal phenotype seen in α1KO mice. PCα1KO mice exhibited cerebellar ataxia starting around P12, much earlier than the first signs of progressive Purkinje cell loss, which appears in these mice between P30 and P45. Secondary cell loss was observed in the granular and molecular layers of the cerebellum and the volume of all individual cerebellar nuclei was reduced. In this mouse model with a cell type-specific ablation of Ca(V)2.1 channels, we show that ablation of Ca(V)2.1 channels restricted to Purkinje cells is sufficient to cause cerebellar ataxia. We demonstrate that spatial ablation of Ca(V)2.1 channels may help in unraveling mechanisms of human disease.

  13. Interneuron- and GABAA receptor-specific inhibitory synaptic plasticity in cerebellar Purkinje cells

    Science.gov (United States)

    He, Qionger; Duguid, Ian; Clark, Beverley; Panzanelli, Patrizia; Patel, Bijal; Thomas, Philip; Fritschy, Jean-Marc; Smart, Trevor G.

    2015-07-01

    Inhibitory synaptic plasticity is important for shaping both neuronal excitability and network activity. Here we investigate the input and GABAA receptor subunit specificity of inhibitory synaptic plasticity by studying cerebellar interneuron-Purkinje cell (PC) synapses. Depolarizing PCs initiated a long-lasting increase in GABA-mediated synaptic currents. By stimulating individual interneurons, this plasticity was observed at somatodendritic basket cell synapses, but not at distal dendritic stellate cell synapses. Basket cell synapses predominantly express β2-subunit-containing GABAA receptors; deletion of the β2-subunit ablates this plasticity, demonstrating its reliance on GABAA receptor subunit composition. The increase in synaptic currents is dependent upon an increase in newly synthesized cell surface synaptic GABAA receptors and is abolished by preventing CaMKII phosphorylation of GABAA receptors. Our results reveal a novel GABAA receptor subunit- and input-specific form of inhibitory synaptic plasticity that regulates the temporal firing pattern of the principal output cells of the cerebellum.

  14. Mesenchymal stem cell transplantation ameliorates motor function deterioration of spinocerebellar ataxia by rescuing cerebellar Purkinje cells

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    Ma Wei-Hsien

    2011-08-01

    Full Text Available Abstract Background Spinocerebellar ataxia (SCA refers to a disease entity in which polyglutamine aggregates are over-produced in Purkinje cells (PCs of the cerebellum as well as other neurons in the central nervous system, and the formation of intracellular polyglutamine aggregates result in the loss of neurons as well as deterioration of motor functions. So far there is no effective neuroprotective treatment for this debilitating disease although numerous efforts have been made. Mesenchymal stem cells (MSCs possess multi-lineage differentiation potentials as well as immuno-modulatory properties, and are theoretically good candidates for SCA treatment. The purpose of this study is to investigate whether transplantation of human MSCs (hMSCs can rescue cerebellar PCs and ameliorate motor function deterioration in SCA in a pre-clinical animal model. Method Transgenic mice bearing poly-glutamine mutation in ataxin-2 gene (C57BL/6J SCA2 transgenic mice were serially transplanted with hMSCs intravenously or intracranially before and after the onset of motor function loss. Motor function of mice was evaluated by an accelerating protocol of rotarod test every 8 weeks. Immunohistochemical stain of whole brain sections was adopted to demonstrate the neuroprotective effect of hMSC transplantation on cerebellar PCs and engraftment of hMSCs into mice brain. Results Intravenous transplantation of hMSCs effectively improved rotarod performance of SCA2 transgenic mice and delayed the onset of motor function deterioration; while intracranial transplantation failed to achieve such neuroprotective effect. Immunohistochemistry revealed that intravenous transplantation was more effective in the preservation of the survival of cerebellar PCs and engraftment of hMSCs than intracranial injection, which was compatible to rotarod performance of transplanted mice. Conclusion Intravenous transplantation of hMSCs can indeed delay the onset as well as improve the motor

  15. A deficiency of ceramide biosynthesis causes cerebellar purkinje cell neurodegeneration and lipofuscin accumulation.

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    Lihong Zhao

    2011-05-01

    Full Text Available Sphingolipids, lipids with a common sphingoid base (also termed long chain base backbone, play essential cellular structural and signaling functions. Alterations of sphingolipid levels have been implicated in many diseases, including neurodegenerative disorders. However, it remains largely unclear whether sphingolipid changes in these diseases are pathological events or homeostatic responses. Furthermore, how changes in sphingolipid homeostasis shape the progression of aging and neurodegeneration remains to be clarified. We identified two mouse strains, flincher (fln and toppler (to, with spontaneous recessive mutations that cause cerebellar ataxia and Purkinje cell degeneration. Positional cloning demonstrated that these mutations reside in the Lass1 gene. Lass1 encodes (dihydroceramide synthase 1 (CerS1, which is highly expressed in neurons. Both fln and to mutations caused complete loss of CerS1 catalytic activity, which resulted in a reduction in sphingolipid biosynthesis in the brain and dramatic changes in steady-state levels of sphingolipids and sphingoid bases. In addition to Purkinje cell death, deficiency of CerS1 function also induced accumulation of lipofuscin with ubiquitylated proteins in many brain regions. Our results demonstrate clearly that ceramide biosynthesis deficiency can cause neurodegeneration and suggest a novel mechanism of lipofuscin formation, a common phenomenon that occurs during normal aging and in some neurodegenerative diseases.

  16. Persistent posttetanic depression at cerebellar parallel fiber to Purkinje cell synapses.

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    Astrid Bergerot

    Full Text Available Plasticity at the cerebellar parallel fiber to Purkinje cell synapse may underlie information processing and motor learning. In vivo, parallel fibers appear to fire in short high frequency bursts likely to activate sparsely distributed synapses over the Purkinje cell dendritic tree. Here, we report that short parallel fiber tetanic stimulation evokes a ∼7-15% depression which develops over 2 min and lasts for at least 20 min. In contrast to the concomitantly evoked short-term endocannabinoid-mediated depression, this persistent posttetanic depression (PTD does not exhibit a dependency on the spatial pattern of synapse activation and is not caused by any detectable change in presynaptic calcium signaling. This persistent PTD is however associated with increased paired-pulse facilitation and coefficient of variation of synaptic responses, suggesting that its expression is presynaptic. The chelation of postsynaptic calcium prevents its induction, suggesting that post- to presynaptic (retrograde signaling is required. We rule out endocannabinoid signaling since the inhibition of type 1 cannabinoid receptors, monoacylglycerol lipase or vanilloid receptor 1, or incubation with anandamide had no detectable effect. The persistent PTD is maximal in pre-adolescent mice, abolished by adrenergic and dopaminergic receptors block, but unaffected by adrenergic and dopaminergic agonists. Our data unveils a novel form of plasticity at parallel fiber synapses: a persistent PTD induced by physiologically relevant input patterns, age-dependent, and strongly modulated by the monoaminergic system. We further provide evidence supporting that the plasticity mechanism involves retrograde signaling and presynaptic diacylglycerol.

  17. Cerebellar transcriptional alterations with Purkinje cell dysfunction and loss in mice lacking PGC-1α

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    Elizabeth K Lucas

    2015-01-01

    Full Text Available Alterations in the expression and activity of the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator-1α (ppargc1a or PGC-1α have been reported in multiple movement disorders, yet it is unclear how a lack of PGC-1α impacts transcription and function of the cerebellum, a region with high PGC-1α expression. We show here that mice lacking PGC-1α exhibit ataxia in addition to the previously described deficits in motor coordination. Using q-RT-PCR in cerebellar homogenates from PGC-1α -/- mice, we measured expression of 37 microarray-identified transcripts upregulated by PGC-1α in SH-SY5Y neuroblastoma cells with neuroanatomical overlap with PGC-1α or parvalbumin (PV, a calcium buffer highly expressed by Purkinje cells. We found significant reductions in transcripts with synaptic (complexin1, Cplx1; Pacsin2, structural (neurofilament heavy chain, Nefh, and metabolic (isocitrate dehydrogenase 3a, Idh3a; neutral cholesterol ester hydrolase 1, Nceh1; pyruvate dehydrogenase alpha 1, Pdha1; phytanoyl-CoA hydroxylase, Phyh; ubiquinol-cytochrome c reductase, Rieske iron-sulfur polypeptide 1, Uqcrfs1 functions. Using conditional deletion of PGC-1α in PV-positive neurons, we determined that 50% of PGC-1α expression and a reduction in a subset of these transcripts could be explained by its concentration in PV-positive neuronal populations in the cerbellum. To determine whether there were functional consequences associated with these changes, we conducted stereological counts and spike rate analysis in Purkinje cells, a cell type rich in PV, from PGC-1α -/- mice. We observed a significant loss of Purkinje cells by six weeks of age, and the remaining Purkinje cells exhibited a 50% reduction in spike rate. Together, these data highlight the complexity of PGC-1α’s actions in the central nervous system and suggest that dysfunction in multiple cell types contribute to motor deficits in the context of PGC-1α deficiency.

  18. Cerebellar transcriptional alterations with Purkinje cell dysfunction and loss in mice lacking PGC-1α

    Science.gov (United States)

    Lucas, Elizabeth K.; Reid, Courtney S.; McMeekin, Laura J.; Dougherty, Sarah E.; Floyd, Candace L.; Cowell, Rita M.

    2014-01-01

    Alterations in the expression and activity of the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator-1α (ppargc1a or PGC-1α) have been reported in multiple movement disorders, yet it is unclear how a lack of PGC-1α impacts transcription and function of the cerebellum, a region with high PGC-1α expression. We show here that mice lacking PGC-1α exhibit ataxia in addition to the previously described deficits in motor coordination. Using q-RT-PCR in cerebellar homogenates from PGC-1α−/− mice, we measured expression of 37 microarray-identified transcripts upregulated by PGC-1α in SH-SY5Y neuroblastoma cells with neuroanatomical overlap with PGC-1α or parvalbumin (PV), a calcium buffer highly expressed by Purkinje cells. We found significant reductions in transcripts with synaptic (complexin1, Cplx1; Pacsin2), structural (neurofilament heavy chain, Nefh), and metabolic (isocitrate dehydrogenase 3a, Idh3a; neutral cholesterol ester hydrolase 1, Nceh1; pyruvate dehydrogenase alpha 1, Pdha1; phytanoyl-CoA hydroxylase, Phyh; ubiquinol-cytochrome c reductase, Rieske iron-sulfur polypeptide 1, Uqcrfs1) functions. Using conditional deletion of PGC-1α in PV-positive neurons, we determined that 50% of PGC-1α expression and a reduction in a subset of these transcripts could be explained by its concentration in PV-positive neuronal populations in the cerbellum. To determine whether there were functional consequences associated with these changes, we conducted stereological counts and spike rate analysis in Purkinje cells, a cell type rich in PV, from PGC-1α−/− mice. We observed a significant loss of Purkinje cells by 6 weeks of age, and the remaining Purkinje cells exhibited a 50% reduction in spike rate. Together, these data highlight the complexity of PGC-1α's actions in the central nervous system and suggest that dysfunction in multiple cell types contribute to motor deficits in the context of PGC-1α deficiency. PMID

  19. Increased GAD67 mRNA expression in cerebellar interneurons in autism: implications for Purkinje cell dysfunction.

    Science.gov (United States)

    Yip, Jane; Soghomonian, Jean-Jacques; Blatt, Gene J

    2008-02-15

    It has been widely reported that in autism, the number of Purkinje cells (PCs) is decreased, and recently, decreased expression of glutamic acid decarboxylase 67 (GAD67) mRNA in Purkinje cells also has been observed. However, the autism literature has not addressed key GABAergic inputs into Purkinje cells. Inhibitory basket and stellate cell interneurons in the molecular layer of the cerebellar cortex provide direct key GABAergic input into Purkinje cells and could potently influence the output of Purkinje cells to deep cerebellar nuclei. We investigated the capacity for interneuronal synthesis of gamma-amino butyric acid (GABA) in both types of interneurons that innervate the remaining PCs in the posterolateral cerebellar hemisphere in autism. The level of GAD67 mRNA, one of the isoforms of the key synthesizing enzymes for GABA, was quantified at the single-cell level using in situ hybridization in brains of autistic and aged-matched controls. The National Institutes of Health imaging system showed that expression of GAD67 mRNA in basket cells was significantly up-regulated, by 28%, in eight autistic brains compared with that in eight control brains (mean +/- SEM pixels per cell, 1.03 +/- 0.05 versus 0.69 +/- 0.05, respectively; P levels, but this did not reach significance. The results suggest that basket cells likely provide increased GABAergic feed-forward inhibition to PCs in autism, directly affecting PC output to target neurons in the dentate nucleus and potentially disrupting its modulatory role in key motor and/or cognitive behaviors in autistic individuals.

  20. Ectopic overexpression of engrailed-2 in cerebellar Purkinje cells causes restricted cell loss and retarded external germinal layer development at lobule junctions.

    Science.gov (United States)

    Baader, S L; Sanlioglu, S; Berrebi, A S; Parker-Thornburg, J; Oberdick, J

    1998-03-01

    Members of the En and Wnt gene families seem to play a key role in the early specification of the brain territory that gives rise to the cerebellum, the midhindbrain junction. To analyze the possible continuous role of the En and Wnt signaling pathway in later cerebellar patterning and function, we expressed En-2 ectopically in Purkinje cells during late embryonic and postnatal cerebellar development. As a result of this expression, the cerebellum is greatly reduced in size, and Purkinje cell numbers throughout the cerebellum are reduced by more than one-third relative to normal animals. Detailed analysis of both adult and developing cerebella reveals a pattern of selectivity to the loss of Purkinje cells and other cerebellar neurons. This is observed as a general loss of prominence of cerebellar fissures that is highlighted by a total loss of sublobular fissures. In contrast, mediolateral patterning is generally only subtly affected. That En-2 overexpression selectively affects Purkinje cells in the transition zone between lobules is evidenced by direct observation of selective Purkinje cell loss in certain fissures and by the observation that growth and migration of the external germinal layer (EGL) is selectively retarded in the deep fissures during early postnatal development. Thus, in addition to demonstrating the critical role of Purkinje cells in the generation and migration of granule cells, the heterogeneous distribution of cellular effects induced by ectopic En expression suggests a relatively late morphogenetic role for this and other segment polarity proteins, mainly oriented at lobule junctions.

  1. Ethanol Modulates the Spontaneous Complex Spike Waveform of Cerebellar Purkinje Cells Recorded in vivo in Mice

    Science.gov (United States)

    Zhang, Guang-Jian; Wu, Mao-Cheng; Shi, Jin-Di; Xu, Yin-Hua; Chu, Chun-Ping; Cui, Song-Biao; Qiu, De-Lai

    2017-01-01

    Cerebellar Purkinje cells (PCs) are sensitive to ethanol, but the effect of ethanol on spontaneous complex spike (CS) activity in these cells in vivo is currently unknown. Here, we investigated the effect of ethanol on spontaneous CS activity in PCs in urethane-anesthetized mice using in vivo patch-clamp recordings and pharmacological manipulation. Ethanol (300 mM) induced a decrease in the CS-evoked pause in simple spike (SS) firing and in the amplitude of the afterhyperpolarization (AHP) under current clamp conditions. Under voltage-clamp conditions, ethanol significantly decreased the area under the curve (AUC) and the number of CS spikelets, without changing the spontaneous frequency of the CSs or the instantaneous frequency of the CS spikelets. Ethanol-induced a decrease in the AUC of spontaneous CSs was concentration dependent. The EC50 of ethanol for decreasing the AUC of spontaneous CSs was 168.5 mM. Blocking N-methyl-D-aspartate receptors (NMDARs) failed to prevent the ethanol-induced decreases in the CS waveform parameters. However, blockade of cannabinoid receptor 1 (CB1) significantly suppressed the ethanol-induced effects on the CS-evoked pause in SS firing, amplitude of the AHP, spikelet number and the AUC of CSs. Moreover, a CB1 receptor agonist not only reduced the number of spikelets and the AUC of CSs, but also prevented the ethanol-induced inhibition of CS activity. Our results indicate that ethanol inhibits CS activity via activation of the CB1 receptor in vivo in mice, suggesting that excessive ethanol intake inhibits climbing fiber (CF)–PC synaptic transmission by modulating CB1 receptors in the cerebellar cortex. PMID:28293172

  2. Purkinje cell heterotopy with cerebellar hypoplasia in two free-living American kestrels (Falco sparverius)

    Science.gov (United States)

    Two wild fledgling kestrels exhibited lack of motor coordination, postural reaction deficits, and abnormal propioception. At necropsy, the cerebellum and brainstem were markedly underdeveloped. Microscopically, there was Purkinje cells heterotopy, abnormal circuitry, and hypoplasia with defective fo...

  3. Cbln1 regulates rapid formation and maintenance of excitatory synapses in mature cerebellar Purkinje cells in vitro and in vivo.

    Science.gov (United States)

    Ito-Ishida, Aya; Miura, Eriko; Emi, Kyoichi; Matsuda, Keiko; Iijima, Takatoshi; Kondo, Tetsuro; Kohda, Kazuhisa; Watanabe, Masahiko; Yuzaki, Michisuke

    2008-06-04

    Although many synapse-organizing molecules have been identified in vitro, their functions in mature neurons in vivo have been mostly unexplored. Cbln1, which belongs to the C1q/tumor necrosis factor superfamily, is the most recently identified protein involved in synapse formation in the mammalian CNS. In the cerebellum, Cbln1 is predominantly produced and secreted from granule cells; cbln1-null mice show ataxia and a severe reduction in the number of synapses between Purkinje cells and parallel fibers (PFs), the axon bundle of granule cells. Here, we show that application of recombinant Cbln1 specifically and reversibly induced PF synapse formation in dissociated cbln1-null Purkinje cells in culture. Cbln1 also rapidly induced electrophysiologically functional and ultrastructurally normal PF synapses in acutely prepared cbln1-null cerebellar slices. Furthermore, a single injection of recombinant Cbln1 rescued severe ataxia in adult cbln1-null mice in vivo by completely, but transiently, restoring PF synapses. Therefore, Cbln1 is a unique synapse organizer that is required not only for the normal development of PF-Purkinje cell synapses but also for their maintenance in the mature cerebellum both in vitro and in vivo. Furthermore, our results indicate that Cbln1 can also rapidly organize new synapses in adult cerebellum, implying its therapeutic potential for cerebellar ataxic disorders.

  4. High dosage of monosodium glutamate causes deficits of the motor coordination and the number of cerebellar Purkinje cells of rats.

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    Prastiwi, D; Djunaidi, A; Partadiredja, G

    2015-11-01

    Monosodium glutamate (MSG) has been widely used throughout the world as a flavoring agent of food. However, MSG at certain dosages is also thought to cause damage to many organs, including cerebellum. This study aimed at investigating the effects of different doses of MSG on the motor coordination and the number of Purkinje cells of the cerebellum of Wistar rats. A total of 24 male rats aged 4 to 5 weeks were divided into four groups, namely, control (C), T2.5, T3, and T3.5 groups, which received intraperitoneal injection of 0.9% sodium chloride solution, 2.5 mg/g body weight (bw) of MSG, 3.0 mg/g bw of MSG, and 3.5 mg/g bw of MSG, respectively, for 10 consecutive days. The motor coordination of the rats was examined prior and subsequent to the treatment. The number of cerebellar Purkinje cells was estimated using physical fractionator method. It has been found that the administration of MSG at a dosage of 3.5 mg/g bw, but not at lower dosages, caused a significant decrease of motor coordination and the estimated total number of Purkinje cells of rats. There was also a significant correlation between motor coordination and the total number of Purkinje cells.

  5. Differential GABAergic and glycinergic inputs of inhibitory interneurons and Purkinje cells to principal cells of the cerebellar nuclei.

    Science.gov (United States)

    Husson, Zoé; Rousseau, Charly V; Broll, Ilja; Zeilhofer, Hanns Ulrich; Dieudonné, Stéphane

    2014-07-09

    The principal neurons of the cerebellar nuclei (CN), the sole output of the olivo-cerebellar system, receive a massive inhibitory input from Purkinje cells (PCs) of the cerebellar cortex. Morphological evidence suggests that CN principal cells are also contacted by inhibitory interneurons, but the properties of this connection are unknown. Using transgenic, tracing, and immunohistochemical approaches in mice, we show that CN interneurons form a large heterogeneous population with GABA/glycinergic phenotypes, distinct from GABAergic olive-projecting neurons. CN interneurons are found to contact principal output neurons, via glycine receptor (GlyR)-enriched synapses, virtually devoid of the main GABA receptor (GABAR) subunits α1 and γ2. Those clusters account for 5% of the total number of inhibitory receptor clusters on principal neurons. Brief optogenetic stimulations of CN interneurons, through selective expression of channelrhodopsin 2 after viral-mediated transfection of the flexed gene in GlyT2-Cre transgenic mice, evoked fast IPSCs in principal cells. GlyR activation accounted for 15% of interneuron IPSC amplitude, while the remaining current was mediated by activation of GABAR. Surprisingly, small GlyR clusters were also found at PC synapses onto principal CN neurons in addition to α1 and γ2 GABAR subunits. However, GlyR activation was found to account for <3% of the PC inhibitory synaptic currents evoked by electrical stimulation. This work establishes CN glycinergic neurons as a significant source of inhibition to CN principal cells, forming contacts molecularly distinct from, but functionally similar to, Purkinje cell synapses. Their impact on CN output, motor learning, and motor execution deserves further investigation.

  6. Cerebellar cortex development in the weaver condition presents regional and age-dependent abnormalities without differences in Purkinje cells neurogenesis.

    Science.gov (United States)

    Martí, Joaquín; Santa-Cruz, María C; Hervás, José P; Bayer, Shirley A; Villegas, Sandra

    2016-01-01

    Ataxias are neurological disorders associated with the degeneration of Purkinje cells (PCs). Homozygous weaver mice (wv/wv) have been proposed as a model for hereditary cerebellar ataxia because they present motor abnormalities and PC loss. To ascertain the physiopathology of the weaver condition, the development of the cerebellar cortex lobes was examined at postnatal day (P): P8, P20 and P90. Three approaches were used: 1) quantitative determination of several cerebellar features; 2) qualitative evaluation of the developmental changes occurring in the cortical lobes; and 3) autoradiographic analyses of PC generation and placement. Our results revealed a reduction in the size of the wv/wv cerebellum as a whole, confirming previous results. However, as distinguished from these reports, we observed that quantified parameters contribute differently to the abnormal growth of the wv/wv cerebellar lobes. Qualitative analysis showed anomalies in wv/wv cerebellar cytoarchitecture, depending on the age and lobe analyzed. Such abnormalities included the presence of the external granular layer after P20 and, at P90, ectopic cells located in the molecular layer following several placement patterns. Finally, we obtained autoradiographic evidence that wild-type and wv/wv PCs presented similar neurogenetic timetables, as reported. However, the innovative character of this current work lies in the fact that the neurogenetic gradients of wv/wv PCs were not modified from P8 to P90. A tendency for the accumulation of late-formed PCs in the anterior and posterior lobes was found, whereas early-generated PCs were concentrated in the central and inferior lobes. These data suggested that wv/wv PCs may migrate properly to their final destinations. The extrapolation of our results to patients affected with cerebellar ataxias suggests that all cerebellar cortex lobes are affected with several age-dependent alterations in cytoarchitectonics. We also propose that PC loss may be regionally

  7. Physiology, morphology and detailed passive models of guinea-pig cerebellar Purkinje cells.

    Science.gov (United States)

    Rapp, M; Segev, I; Yarom, Y

    1994-01-01

    1. Purkinje cells (PCs) from guinea-pig cerebellar slices were physiologically characterized using intracellular techniques. Extracellular caesium ions were used to linearize the membrane properties of PCs near the resting potential. Under these conditions the average input resistance, RN, was 29 M omega, the average system time constant, tau 0, was 82 ms and the average cable length, LN, was 0.59. 2. Three PCs were fully reconstructed following physiological measurements and staining with horseradish peroxidase. Assuming that each spine has an area of 1 micron 2 and that the spine density over the spiny dendrites is ten spines per micrometre length, the total membrane area of each PC is approximately 150,000 microns 2, of which approximately 100,000 microns 2 is in the spines. 3. Detailed passive cable and compartmental models were built for each of the three reconstructed PCs. Computational methods were devised to incorporate globally the huge number of spines into these models. In all three cells the models predict that the specific membrane resistivity, Rm, of the soma is much lower than the dendritic Rm (approximately 500 and approximately 100,000 omega cm2 respectively). The specific membrane capacitance, Cm, is estimated to be 1.5-2 muF cm-2 and the specific cytoplasm resistivity, Ri, is 250 omega cm. 4. The average cable length of the dendrites according to the model is 0.13 lambda, suggesting that under caesium conditions PCs are electrically very compact. Brief somatic spikes, however, are expected to attenuate 30-fold when spreading passively into the dendritic terminals. A simulated 200 Hz train of fast, 90 mV somatic spikes produced a smooth 12 mV steady depolarization at the dendritic terminals. 5. A transient synaptic conductance increase, with a 1 nS peak at 0.5 ms and a driving force of 60 mV, is expected to produce approximately 20 mV peak depolarization at the spine head membrane. This EPSP then attenuates between 200- and 900-fold into the soma

  8. Frequency-dependent reliability of spike propagation is function of axonal voltage-gated sodium channels in cerebellar Purkinje cells.

    Science.gov (United States)

    Yang, Zhilai; Wang, Jin-Hui

    2013-12-01

    The spike propagation on nerve axons, like synaptic transmission, is essential to ensure neuronal communication. The secure propagation of sequential spikes toward axonal terminals has been challenged in the neurons with a high firing rate, such as cerebellar Purkinje cells. The shortfall of spike propagation makes some digital spikes disappearing at axonal terminals, such that the elucidation of the mechanisms underlying spike propagation reliability is crucial to find the strategy of preventing loss of neuronal codes. As the spike propagation failure is influenced by the membrane potentials, this process is likely caused by altering the functional status of voltage-gated sodium channels (VGSC). We examined this hypothesis in Purkinje cells by using pair-recordings at their somata and axonal blebs in cerebellar slices. The reliability of spike propagation was deteriorated by elevating spike frequency. The frequency-dependent reliability of spike propagation was attenuated by inactivating VGSCs and improved by removing their inactivation. Thus, the functional status of axonal VGSCs influences the reliability of spike propagation.

  9. Diacylglycerol kinase ε localizes to subsurface cisterns of cerebellar Purkinje cells.

    Science.gov (United States)

    Hozumi, Yasukazu; Fujiwara, Hiroki; Kaneko, Kenya; Fujii, Satoshi; Topham, Matthew K; Watanabe, Masahiko; Goto, Kaoru

    2017-02-13

    Following activation of Gq protein-coupled receptors, phospholipase C yields a pair of second messengers: diacylglycerol (DG) and inositol 1,4,5-trisphosphate. Diacylglycerol kinase (DGK) phosphorylates DG to produce phosphatidic acid, another second messenger. Of the DGK family, DGKε is the only DGK isoform that exhibits substrate specificity for DG with an arachidonoyl acyl chain at the sn-2 position. Recently, we demonstrated that hydrophobic residues in the N-terminus of DGKε play an important role in targeting the endoplasmic reticulum in transfected cells. However, its cellular expression and subcellular localization in the brain remain elusive. In the present study, we investigate this issue using specific DGKε antibody. DGKε was richly expressed in principal neurons of higher brain regions, including pyramidal cells in the hippocampus and neocortex, medium spiny neurons in the striatum and Purkinje cells in the cerebellum. In Purkinje cells, DGKε was localized to the subsurface cisterns and colocalized with inositol 1,4,5-trisphosphate receptor-1 in dendrites and axons. In dendrites of Purkinje cells, DGKε was also distributed in close apposition to DG lipase-α, which catalyzes arachidonoyl-DG to produce 2-arachidonoyl glycerol, a major endocannabinoid in the brain. Behaviorally, DGKε-knockout mice exhibited hyper-locomotive activities and impaired motor coordination and learning. These findings suggest that DGKε plays an important role in neuronal and brain functions through its distinct neuronal expression and subcellular localization and also through coordinated arrangement with other molecules involving the phosphoinositide signaling pathway.

  10. Anti-Yo antibody uptake and interaction with its intracellular target antigen causes Purkinje cell death in rat cerebellar slice cultures: a possible mechanism for paraneoplastic cerebellar degeneration in humans with gynecological or breast cancers.

    Directory of Open Access Journals (Sweden)

    John E Greenlee

    Full Text Available Anti-Yo antibodies are immunoglobulin G (IgG autoantibodies reactive with a 62 kDa Purkinje cell cytoplasmic protein. These antibodies are closely associated with paraneoplastic cerebellar degeneration in the setting of gynecological and breast malignancies. We have previously demonstrated that incubation of rat cerebellar slice cultures with patient sera and cerebrospinal fluid containing anti-Yo antibodies resulted in Purkinje cell death. The present study addressed three fundamental questions regarding the role of anti-Yo antibodies in disease pathogenesis: 1 Whether the Purkinje cell cytotoxicity required binding of anti-Yo antibody to its intraneuronal 62 kDa target antigen; 2 whether Purkinje cell death might be initiated by antibody-dependent cellular cytotoxicity rather than intracellular antibody binding; and 3 whether Purkinje cell death might simply be a more general result of intracellular antibody accumulation, rather than of specific antibody-antigen interaction. In our study, incubation of rat cerebellar slice cultures with anti-Yo IgG resulted in intracellular antibody binding, and cell death. Infiltration of the Purkinje cell layer by cells of macrophage/microglia lineage was not observed until extensive cell death was already present. Adsorption of anti-Yo IgG with its 62 kDa target antigen abolished both antibody accumulation and cytotoxicity. Antibodies to other intracellular Purkinje cell proteins were also taken up by Purkinje cells and accumulated intracellularly; these included calbindin, calmodulin, PCP-2, and patient anti-Purkinje cell antibodies not reactive with the 62 kDa Yo antigen. However, intracellular accumulation of these antibodies did not affect Purkinje cell viability. The present study is the first to demonstrate that anti-Yo antibodies cause Purkinje cell death by binding to the intracellular 62 kDa Yo antigen. Anti-Yo antibody cytotoxicity did not involve other antibodies or factors present in patient

  11. Intracellular correlates of acquisition and long-term memory of classical conditioning in Purkinje cell dendrites in slices of rabbit cerebellar lobule HVI.

    Science.gov (United States)

    Schreurs, B G; Gusev, P A; Tomsic, D; Alkon, D L; Shi, T

    1998-07-15

    Intradendritic recordings in Purkinje cells from a defined area in parasaggital slices of cerebellar lobule HVI, obtained after rabbits were given either paired (classical conditioning) or explicitly unpaired (control) presentations of tone and periorbital electrical stimulation, were used to assess the nature and duration of conditioning-specific changes in Purkinje cell dendritic membrane excitability. We found a strong relationship between the level of conditioning and Purkinje cell dendritic membrane excitability after initial acquisition of the conditioned response. Moreover, conditioning-specific increases in Purkinje cell excitability were still present 1 month after classical conditioning. Although dendritically recorded membrane potential, input resistance, and amplitude of somatic and dendritic spikes were not different in cells from paired or control animals, the size of a potassium channel-mediated transient hyperpolarization was significantly smaller in cells from animals that received classical conditioning. In slices of lobule HVI obtained from naive rabbits, the conditioning-related increases in membrane excitability could be mimicked by application of potassium channel antagonist tetraethylammonium chloride, iberiotoxin, or 4-aminopyridine. However, only 4-aminopyridine was able to reduce the transient hyperpolarization. The pharmacological data suggest a role for potassium channels and, possibly, channels mediating an IA-like current, in learning-specific changes in membrane excitability. The conditioning-specific increase in Purkinje cell dendritic excitability produces an afterhyperpolarization, which is hypothesized to release the cerebellar deep nuclei from inhibition, allowing conditioned responses to be elicited via the red nucleus and accessory abducens motorneurons.

  12. Selective loss of Purkinje cells in a patient with anti-gliadin-antibody-positive autoimmune cerebellar ataxia

    Directory of Open Access Journals (Sweden)

    Hasegawa Akira

    2011-02-01

    Full Text Available Abstract The patient was an 84-year-old woman who had the onset of truncal ataxia at age 77 and a history of Basedow's disease. Her ataxic gait gradually deteriorated. She could not walk without support at age 81 and she was admitted to our hospital at age 83. Gaze-evoked nystagmus and dysarthria were observed. Mild ataxia was observed in all limbs. Her deep tendon reflex and sense of position were normal. IgA anti-gliadin antibody, IgG anti-gliadin antibody, anti-SS-A/Ro antibody, anti-SS-B/La antibody and anti-TPO antibody were positive. A conventional brain MRI did not show obvious cerebellar atrophy. However, MRI voxel based morphometry (VBM and SPECT-eZIS revealed cortical cerebellar atrophy and reduced cerebellar blood flow. IVIg treatment was performed and was moderately effective. After her death at age 85, the patient was autopsied. Neuropathological findings were as follows: selective loss of Purkinje cells; no apparent degenerative change in the efferent pathways, such as the dentate nuclei or vestibular nuclei; no prominent inflammatory reaction. From these findings, we diagnosed this case as autoimmune cerebellar atrophy associated with gluten ataxia. All 3 autopsies previously reported on gluten ataxia have noted infiltration of inflammatory cells in the cerebellum. In this case, we postulated that the infiltration of inflammatory cells was not found because the patient's condition was based on humoral immunity. The clinical conditions of gluten ataxia have not yet been properly elucidated, but are expected to be revealed as the number of autopsied cases increases.

  13. Dendritic Kv3.3 potassium channels in cerebellar purkinje cells regulate generation and spatial dynamics of dendritic Ca2+ spikes.

    Science.gov (United States)

    Zagha, Edward; Manita, Satoshi; Ross, William N; Rudy, Bernardo

    2010-06-01

    Purkinje cell dendrites are excitable structures with intrinsic and synaptic conductances contributing to the generation and propagation of electrical activity. Voltage-gated potassium channel subunit Kv3.3 is expressed in the distal dendrites of Purkinje cells. However, the functional relevance of this dendritic distribution is not understood. Moreover, mutations in Kv3.3 cause movement disorders in mice and cerebellar atrophy and ataxia in humans, emphasizing the importance of understanding the role of these channels. In this study, we explore functional implications of this dendritic channel expression and compare Purkinje cell dendritic excitability in wild-type and Kv3.3 knockout mice. We demonstrate enhanced excitability of Purkinje cell dendrites in Kv3.3 knockout mice, despite normal resting membrane properties. Combined data from local application pharmacology, voltage clamp analysis of ionic currents, and assessment of dendritic Ca(2+) spike threshold in Purkinje cells suggest a role for Kv3.3 channels in opposing Ca(2+) spike initiation. To study the physiological relevance of altered dendritic excitability, we measured [Ca(2+)](i) changes throughout the dendritic tree in response to climbing fiber activation. Ca(2+) signals were specifically enhanced in distal dendrites of Kv3.3 knockout Purkinje cells, suggesting a role for dendritic Kv3.3 channels in regulating propagation of electrical activity and Ca(2+) influx in distal dendrites. These findings characterize unique roles of Kv3.3 channels in dendrites, with implications for synaptic integration, plasticity, and human disease.

  14. Facial stimulation induces long-term depression at cerebellar molecular layer interneuron–Purkinje cell synapses in vivo in mice

    Directory of Open Access Journals (Sweden)

    De-Lai eQiu

    2015-06-01

    Full Text Available Cerebellar long-term synaptic plasticity has been proposed to provide a cellular mechanism for motor learning. Numerous studies have demonstrated the induction and mechanisms of synaptic plasticity at parallel fiber–Purkinje cell (PF–PC, parallel fiber–molecular layer interneurons (PF–MLI and mossy fiber–granule cell (MF–GC synapses, but no study has investigated sensory stimulation-evoked synaptic plasticity at MLI–PC synapses in the cerebellar cortex of living animals. We studied the expression and mechanism of MLI–PC GABAergic synaptic plasticity induced by a train of facial stimulation in urethane-anesthetized mice by cell-attached recordings and pharmacological methods. We found that 1 Hz, but not a 2 Hz or 4 Hz, facial stimulation induced a long-term depression (LTD of GABAergic transmission at MLI–PC synapses, which was accompanied with a decrease in the stimulation-evoked pause of spike firing in PCs, but did not induce a significant change in the properties of the sensory-evoked spike events of MLIs. The MLI–PC GABAergic LTD could be prevented by blocking cannabinoid type 1 (CB1 receptors, and could be pharmacologically induced by a CB1 receptor agonist. Additionally, 1 Hz facial stimulation delivered in the presence of a metabotropic glutamate receptor 1 (mGluR1 antagonist, JNJ16259685, still induced the MLI–PC GABAergic LTD, whereas blocking N-methyl-D-aspartate (NMDA receptors during 1 Hz facial stimulation abolished the expression of MLI–PC GABAergic LTD. These results indicate that sensory stimulation can induce an endocannabinoid (eCB-dependent LTD of GABAergic transmission at MLI–PC synapses via activation of NMDA receptors in cerebellar cortical Crus II in vivo in mice. Our results suggest that the sensory stimulation-evoked MLI–PC GABAergic synaptic plasticity may play a critical role in motor learning in animals.

  15. Synaptic responses evoked by tactile stimuli in Purkinje cells in mouse cerebellar cortex Crus II in vivo.

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    Chun-Ping Chu

    Full Text Available BACKGROUND: Sensory stimuli evoke responses in cerebellar Purkinje cells (PCs via the mossy fiber-granule cell pathway. However, the properties of synaptic responses evoked by tactile stimulation in cerebellar PCs are unknown. The present study investigated the synaptic responses of PCs in response to an air-puff stimulation on the ipsilateral whisker pad in urethane-anesthetized mice. METHODS AND MAIN RESULTS: Thirty-three PCs were recorded from 48 urethane-anesthetized adult (6-8-week-old HA/ICR mice by somatic or dendritic patch-clamp recording and pharmacological methods. Tactile stimulation to the ipsilateral whisker pad was delivered by an air-puff through a 12-gauge stainless steel tube connected with a pressurized injection system. Under current-clamp conditions (I = 0, the air-puff stimulation evoked strong inhibitory postsynaptic potentials (IPSPs in the somata of PCs. Application of SR95531, a specific GABA(A receptor antagonist, blocked IPSPs and revealed stimulation-evoked simple spike firing. Under voltage-clamp conditions, tactile stimulation evoked a sequence of transient inward currents followed by strong outward currents in the somata and dendrites in PCs. Application of SR95531 blocked outward currents and revealed excitatory postsynaptic currents (EPSCs in somata and a temporal summation of parallel fiber EPSCs in PC dendrites. We also demonstrated that PCs respond to both the onset and offset of the air-puff stimulation. CONCLUSIONS: These findings indicated that tactile stimulation induced asynchronous parallel fiber excitatory inputs onto the dendrites of PCs, and failed to evoke strong EPSCs and spike firing in PCs, but induced the rapid activation of strong GABA(A receptor-mediated inhibitory postsynaptic currents in the somata and dendrites of PCs in the cerebellar cortex Crus II in urethane-anesthetized mice.

  16. Altered dendritic development of cerebellar Purkinje cells in slice cultures from protein kinase C gamma-deficient mice

    NARCIS (Netherlands)

    Schrenk, K; Kapfhammer, JP; Metzger, F

    2002-01-01

    Protein kinase C (PKC) is a key molecule for the expression of long-term depression at the parallel fiber-Purkinje cell synapse in the cerebellum, a well known model for synaptic plasticity, We have recently shown that activity of PKC also profoundly affects the dendritic morphology of Purkinje cell

  17. Preferential Transport and Metabolism of Glucose in Bergmann Glia over Purkinje Cells: A Multiphoton Study of Cerebellar Slices

    Institute of Scientific and Technical Information of China (English)

    L.F.BARROS; R.COURJARET; P.JAKOBY; A.LOAIZA; C.LOHR; J.W.DEITMER

    2009-01-01

    了解不同类型的细胞如何处理葡萄糖有助于解释能量供应是如何是如何根据大脑能量需求来进行调整的.荧光追踪结合共聚焦显微镜技术已用于研究培养的脑细胞摄取葡萄糖的实时动态过程.本文采用这种技术利用多光子显微镜观察急性制备的大鼠小脑脑片.带荧光的葡萄糖类似物2NBDG和6NBDG在小脑皮质的分子层中的转运速度比其在蒲肯野细胞胞体和颗粒细胞中快若干倍.洗脱游离示踪剂后,可见大部分磷酸化示踪剂都位于Bergmann胶质细胞,用胶质细胞标记物sulforhodamine 101免疫染色后进一步确认这一结果.有效回收荧光光漂白后显示,2NBDG-P可通过Bergmann胶质细胞之间的缝隙连接沿着分子层水平扩散.本文的结果表明在急性小脑切片中,Bergmann胶质细胞对葡萄糖的转运能力和糖酵解率高于蒲肯野细胞若干倍.由于小脑主要由葡萄糖提供能量,蒲肯野神经元被认为比Bergmann胶质细胞更耗能量,这些结果表明,在胶质细胞和神经元之间存在类似乳酸的能量代谢物介导的环路.%Knowing how different cell types handle glucose should help to decipher how energy supply is adjusted to energy demand in the brain. Previously, the uptake of glucose by cultured brain cells was studied in real-time using fluorescent tracers and confocal microscopy. Here, we have adapted this technique to acute slices prepared from the rat cerebellum by means of multiphoton microscopy. The transport of the fluorescent glucose analogs 2NBDG and 6NBDG was several-fold faster in the molecular layer of the cerebellar cortex than in Purkinje cell somata and granule cells. After washout of free tracer, it became apparent that most phosphorylated tracer was located in Bergmann glia, which was confirmed by counterstaining with the glial marker sulforhodamine 101. The effective recovery of fluorescence after photobleaching showed that 2NBDG-P can diffuse

  18. Alternative splicing generates a smaller assortment of CaV2.1 transcripts in cerebellar Purkinje cells than in the cerebellum.

    Science.gov (United States)

    Kanumilli, Srinivasan; Tringham, Elizabeth W; Payne, C Elizabeth; Dupere, Jonathan R B; Venkateswarlu, Kanamarlapudi; Usowicz, Maria M

    2006-01-12

    P/Q-type calcium channels control many calcium-driven functions in the brain. The CACNA1A gene encoding the pore-forming CaV2.1 (alpha1A) subunit of P/Q-type channels undergoes alternative splicing at multiple loci. This results in channel variants with different phenotypes. However, the combinatorial patterns of alternative splice events at two or more loci, and hence the diversity of CaV2.1 transcripts, are incompletely defined for specific brain regions and types of brain neurons. Using RT-PCR and splice variant-specific primers, we have identified multiple CaV2.1 transcript variants defined by different pairs of splice events in the cerebellum of adult rat. We have uncovered new splice variations between exons 28 and 34 (some of which predict a premature stop codon) and a new variation in exon 47 (which predicts a novel extended COOH-terminus). Single cell RT-PCR reveals that each individual cerebellar Purkinje neuron also expresses multiple alternative CaV2.1 transcripts, but the assortment is smaller than in the cerebellum. Two of these variants encode different extended COOH-termini which are not the same as those previously reported in Purkinje cells of the mouse. Our patch-clamp recordings show that calcium channel currents in the soma and dendrites of Purkinje cells are largely inhibited by a concentration of omega-agatoxin IVA selective for P-type over Q-type channels, suggesting that the different transcripts may form phenotypic variants of P-type calcium channels in Purkinje cells. These results expand the known diversity of CaV2.1 transcripts in cerebellar Purkinje cells, and propose the selective expression of distinct assortments of CaV2.1 transcripts in different brain neurons and species.

  19. Alcohol impairs long-term depression at the cerebellar parallel fiber-Purkinje cell synapse

    NARCIS (Netherlands)

    A. Belmeguenai (Amor); P. Botta (Paolo); J.T. Weber (John); M. Carta (Mario); M.M. de Ruiter (Martijn); C.I. de Zeeuw (Chris); C.F. Valenzuela (Fernando); C.R.W. Hansel (Christian)

    2008-01-01

    textabstractAcute alcohol consumption causes deficits in motor coordination and gait, suggesting an involvement of cerebellar circuits, which play a role in the fine adjustment of movements and in motor learning. It has previously been shown that ethanol modulates inhibitory transmission in the cere

  20. Low-threshold Ca2+ currents in dendritic recordings from Purkinje cells in rat cerebellar slice cultures.

    Science.gov (United States)

    Mouginot, D; Bossu, J L; Gähwiler, B H

    1997-01-01

    Voltage-dependent Ca2+ conductances were investigated in Purkinje cells in rat cerebellar slice cultures using the whole-cell and cell-attached configurations of the patch-clamp technique. In the presence of 0.5 mM Ca2+ in the extracellular solution, the inward current activated with a threshold of -55 +/- 1.5 mV and reached a maximal amplitude of 2.3 +/- 0.4 nA at -31 +/- 2 mV. Decay kinetics revealed three distinct components: a fast (24.6 +/- 2 msec time constant), a slow (304 +/- 46 msec time constant), and a nondecaying component. Rundown of the slow and sustained components of the current, or application of antagonists for the P/Q-type Ca2+ channels, allowed isolation of the fast-inactivating Ca2+ current, which had a threshold for activation of -60 mV and reached a maximal amplitude of 0.7 nA at a membrane potential of -33 mV. Both activation and steady-state inactivation of this fast-inactivating Ca2+ current were described with Boltzmann equations, with half-activation and inactivation at -51 mV and -86 mV, respectively. This Ca2+ current was nifedipine-insensitive, but its amplitude was reduced reversibly by bath-application of NiCl2 and amiloride, thus allowing its identification as a T-type Ca2+ current. Channels with a conductance of 7 pS giving rise to a fast T-type ensemble current (insensitive to omega-Aga-IVA) were localized with a high density on the dendritic membrane. Channel activity responsible for the ensemble current sensitive to omega-Aga-IVA was detected with 10 mM Ba2+ as the charge carrier. These channels were distributed with a high density on dendritic membranes and in rare cases were also seen in somatic membrane patches.

  1. The 40-year history of modeling active dendrites in cerebellar Purkinje cells: Emergence of the first single cell 'Community Model'

    Directory of Open Access Journals (Sweden)

    James M Bower

    2015-10-01

    Full Text Available The subject of the effects of the active properties of the Purkinje cell dendrite on neuronal function has been an active subject of study for more than 40 years. Somewhat unusually, some of these investigations, from the outset have involved an interacting combination of experimental and model-based techniques. This paper recounts that 40-year history, and the view of the functional significance of the active properties of the Purkinje cell dendrite that has emerged. It specifically considers the emergence from these efforts of what is arguably the first single cell ‘community’ model in neuroscience. The paper also considers the implications of the development of this model for future studies of the complex properties of neuronal dendrites.

  2. Kv3.3 channels harbouring a mutation of spinocerebellar ataxia type 13 alter excitability and induce cell death in cultured cerebellar Purkinje cells.

    Science.gov (United States)

    Irie, Tomohiko; Matsuzaki, Yasunori; Sekino, Yuko; Hirai, Hirokazu

    2014-01-01

    The cerebellum plays crucial roles in controlling sensorimotor functions. The neural output from the cerebellar cortex is transmitted solely by Purkinje cells (PCs), whose impairment causes cerebellar ataxia. Spinocerebellar ataxia type 13 (SCA13) is an autosomal dominant disease, and SCA13 patients exhibit cerebellar atrophy and cerebellar symptoms. Recent studies have shown that missense mutations in the voltage-gated K(+) channel Kv3.3 are responsible for SCA13. In the rodent brain, Kv3.3 mRNAs are expressed most strongly in PCs, suggesting that the mutations severely affect PCs in SCA13 patients. Nevertheless, how these mutations affect the function of Kv3.3 in PCs and, consequently, the morphology and neuronal excitability of PCs remains unclear. To address these questions, we used lentiviral vectors to express mutant mouse Kv3.3 (mKv3.3) channels harbouring an R424H missense mutation, which corresponds to the R423H mutation in the Kv3.3 channels of SCA13 patients, in mouse cerebellar cultures. The R424H mutant-expressing PCs showed decreased outward current density, broadened action potentials and elevated basal [Ca(2+)]i compared with PCs expressing wild-type mKv3.3 subunits or those expressing green fluorescent protein alone. Moreover, expression of R424H mutant subunits induced impaired dendrite development and cell death selectively in PCs, both of which were rescued by blocking P/Q-type Ca(2+) channels in the culture conditions. We therefore concluded that expression of R424H mutant subunits in PCs markedly affects the function of endogenous Kv3 channels, neuronal excitability and, eventually, basal [Ca(2+)]i, leading to cell death. These results suggest that PCs in SCA13 patients also exhibit similar defects in PC excitability and induced cell death, which may explain the pathology of SCA13.

  3. Pairing of pre- and postsynaptic activities in cerebellar Purkinje cells induces long-term changes in synaptic efficacy in vitro.

    Science.gov (United States)

    Crepel, F; Jaillard, D

    1991-01-01

    1. An in vitro slice preparation of rat cerebellar cortex was used to analyse long-lasting modifications of synaptic transmission at parallel fibre (PF)-Purkinje cell (PC) synapses. These use-dependent changes were induced by pairing PF-mediated EPSPs evoked at low frequency (1 Hz) with different levels of membrane polarization (or bioelectrical activities) of PCs for 15 min. 2. Experiments were performed on forty-eight PCs recorded intracellularly in a conventional perfused chamber, and in fifty other cells maintained in a static chamber either in the presence (n = 21) or in the absence (n = 29) of 400 nM-phorbol 12,13-dibutyrate (PDBu). 3. In these three experimental conditions, PF-mediated EPSPs were always measured on PCs maintained at a holding potential of -75 mV, and further hyperpolarized by constant hyperpolarizing pulses. This allowed us both to test the input resistance of PCs and to avoid their firing during PF-mediated EPSPs. 4. In all cells retained for the present study, latencies of PF-mediated EPSPs evoked at 0.2 Hz were stable during the pre-pairing period, and the same was true for their amplitude and time course. 5. In the perfused chamber, pairing of PF-mediated EPSPs with the same hyperpolarization of PCs as that used for measurements of synaptic responses had no effect on these EPSPs in 30% of PCs. It induced long-term depression (LTD) and long-term potentiation (LTP) in 23 and 47% of the tested cells respectively (n = 17). 6. In the perfused chamber, pairing of PF-mediated EPSPs with moderate depolarization of PCs (n = 19) giving rise to a sustained firing of sodium spikes significantly favoured the appearance of LTP as compared to the previous pairing protocol. However, there were still 27 and 15% of cells which showed no modification and LTD respectively. 7. In contrast, pairing of PF-mediated EPSPs with calcium (Ca2+) spikes evoked by strong depolarization of PCs (n = 12) led to LTD of synaptic transmission in nearly half of the tested

  4. Pairing-specific long-term depression of Purkinje cell excitatory postsynaptic potentials results from a classical conditioning procedure in the rabbit cerebellar slice.

    Science.gov (United States)

    Schreurs, B G; Oh, M M; Alkon, D L

    1996-03-01

    1. Using a rabbit cerebellar slice preparation, we stimulated a classical conditioning procedure by stimulating parallel fiber inputs to Purkinje cells with the use of a brief, high-frequency train of eight constant-current pulses 80 ms before climbing fiber inputs to the same Purkinje cell were stimulated with the use of a brief, lower frequency train of three constant-current pulses. In all experiments, we assessed the effects of stimulation by measuring the peak amplitude of Purkinje cell excitatory postsynaptic potentials (EPSPs) to single parallel fiber test pulses. 2. Intradendritically recorded Purkinje cell EPSPs underwent a long-term (> 20 min) reduction in peak amplitude (30%) after paired stimulation of the parallel and climbing fibers but not after unpaired or parallel fiber alone stimulation. We call this phenomenon pairing-specific long-term depression (PSD). 3. Facilitation of the peak amplitude of a second EPSP elicited by a parallel fiber train occurred both before and after paired stimulation suggesting that the locus of depression was not presynaptic. Depression of the peak amplitude of a depolarizing response to focal application of glutamate following pairings of parallel and climbing fiber stimulation added support to a suggested postsynaptic locus of the PSD effect. 4. The application of aniracetam potentiated EPSP peak amplitude by 40%, but these values returned to baseline as a result of pairings. With the removal of aniracetam from the bath 20 min after pairings, normal levels of pairing-specific EPSP depression were observed, indicating that the effect did not result from direct desensitization of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-proprionic acid (AMPA) receptors. 5. Incubation of slices in the protein kinase inhibitor H-7 potentiated EPSP peak amplitudes slightly (9%), but peak amplitudes returned to baseline levels after pairings. The net reduction in EPSP peak amplitude of classical conditioning.

  5. The postnatal development of cerebellar Purkinje cells in the Gottingen minipig estimated with a new stereological sampling technique--the vertical bar fractionator

    DEFF Research Database (Denmark)

    Jelsing, Jacob; Gundersen, Hans Jørgen Gottlieb; Nielsen, Rune;

    2006-01-01

    demonstrates that a pronounced postnatal neurogenesis in Purkinje cell number and perikaryon volume is part of the growth and development of the cerebellum in the Gottingen minipig. The Purkinje cells of the Gottingen minipig were found to be substantially large compared with human and represents the largest...

  6. Effects of gadolinium-based contrast agents on thyroid hormone receptor action and thyroid hormone-induced cerebellar Purkinje cell morphogenesis

    Directory of Open Access Journals (Sweden)

    Noriyuki Koibuchi

    2016-08-01

    Full Text Available Gadolinium (Gd-based contrast agents (GBCAs are used in diagnostic imaging to enhance the quality of magnetic resonance imaging or angiography. After intravenous injection, GBCAs can accumulate in the brain. Thyroid hormones (THs are critical to the development and functional maintenance of the central nervous system. TH actions in brain are mainly exerted through nuclear TH receptors (TRs. We examined the effects of GBCAs on TR-mediated transcription in CV-1 cells using transient transfection-based reporter assay and thyroid hormone-mediated cerebellar Purkinje cell morphogenesis in primary culture. We also measured the cellular accumulation and viability of Gd after representative GBCA treatments in cultured CV-1 cells. Both linear (Gd-diethylene triamine pentaacetic acid-bis methyl acid, Gd-DTPA-BMA and macrocyclic (Gd-tetraazacyclododecane tetraacetic acid, Gd-DOTA GBCAs were accumulated without inducing cell death in CV-1 cells. In contrast, Gd chloride (GdCl3 treatment induced approximately 100 times higher Gd accumulation and significantly reduced the number of cells. Low doses of Gd-DTPA-BMA (10−8–10−6 M augmented TR-mediated transcription, but the transcription was suppressed at higher dose (10−5 – 10−4 M, with decreased β-galactosidase activity indicating cellular toxicity. TR-mediated transcription was not altered by Gd-DOTA or GdCl3, but the latter induced a significant reduction in β-galactosidase activity at high doses, indicating cellular toxicity. In cerebellar cultures, the dendrite arborization of Purkinje cells induced by 10-9 M T4 was augmented by low-dose Gd-DTPA-BMA (10−7 M but was suppressed by higher dose (10−5 M. Such augmentation by low-dose Gd-DTPA-BMA was not observed with 10-9 M T3, probably because of the greater dendrite arborization by T3; however, the arborization by T3 was suppressed by a higher dose of Gd-DTPA-BMA (10-5 M as seen in T4 treatment. The effect of Gd-DOTA on dendrite arborization

  7. Dendritic planarity of Purkinje cells is independent of Reelin signaling.

    Science.gov (United States)

    Kim, Jinkyung; Park, Tae-Ju; Kwon, Namseop; Lee, Dongmyeong; Kim, Seunghwan; Kohmura, Yoshiki; Ishikawa, Tetsuya; Kim, Kyong-Tai; Curran, Tom; Je, Jung Ho

    2015-07-01

    The dendritic planarity of Purkinje cells is critical for cerebellar circuit formation. In the absence of Crk and CrkL, the Reelin pathway does not function resulting in partial Purkinje cell migration and defective dendritogenesis. However, the relationships among Purkinje cell migration, dendritic development and Reelin signaling have not been clearly delineated. Here, we use synchrotron X-ray microscopy to obtain 3-D images of Golgi-stained Purkinje cell dendrites. Purkinje cells that failed to migrate completely exhibited conical dendrites with abnormal 3-D arborization and reduced dendritic complexity. Furthermore, their spines were fewer in number with a distorted morphology. In contrast, Purkinje cells that migrated successfully displayed planar dendritic and spine morphologies similar to normal cells, despite reduced dendritic complexity. These results indicate that, during cerebellar formation, Purkinje cells migrate into an environment that supports development of dendritic planarity and spine formation. While Reelin signaling is important for the migration process, it does not make a direct major contribution to dendrite formation.

  8. Purkinje cell intrinsic excitability increases after synaptic long term depression.

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    Yang, Zhen; Santamaria, Fidel

    2016-09-01

    Coding in cerebellar Purkinje cells not only depends on synaptic plasticity but also on their intrinsic membrane excitability. We performed whole cell patch-clamp recordings of Purkinje cells in sagittal cerebellar slices in mice. We found that inducing long-term depression (LTD) in the parallel fiber to Purkinje cell synapses results in an increase in the gain of the firing rate response. This increase in excitability is accompanied by an increase in the input resistance and a decrease in the amplitude of the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel-mediated voltage sag. Application of a HCN channel blocker prevents the increase in input resistance and excitability without blocking the expression of synaptic LTD. We conclude that the induction of parallel fiber-Purkinje cell LTD is accompanied by an increase in excitability of Purkinje cells through downregulation of the HCN-mediated h current. We suggest that HCN downregulation is linked to the biochemical pathway that sustains synaptic LTD. Given the diversity of information carried by the parallel fiber system, we suggest that changes in intrinsic excitability enhance the coding capacity of the Purkinje cell to specific input sources.

  9. Cerebellar Nuclear Neurons Use Time and Rate Coding to Transmit Purkinje Neuron Pauses.

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    Sudhakar, Shyam Kumar; Torben-Nielsen, Benjamin; De Schutter, Erik

    2015-12-01

    Neurons of the cerebellar nuclei convey the final output of the cerebellum to their targets in various parts of the brain. Within the cerebellum their direct upstream connections originate from inhibitory Purkinje neurons. Purkinje neurons have a complex firing pattern of regular spikes interrupted by intermittent pauses of variable length. How can the cerebellar nucleus process this complex input pattern? In this modeling study, we investigate different forms of Purkinje neuron simple spike pause synchrony and its influence on candidate coding strategies in the cerebellar nuclei. That is, we investigate how different alignments of synchronous pauses in synthetic Purkinje neuron spike trains affect either time-locking or rate-changes in the downstream nuclei. We find that Purkinje neuron synchrony is mainly represented by changes in the firing rate of cerebellar nuclei neurons. Pause beginning synchronization produced a unique effect on nuclei neuron firing, while the effect of pause ending and pause overlapping synchronization could not be distinguished from each other. Pause beginning synchronization produced better time-locking of nuclear neurons for short length pauses. We also characterize the effect of pause length and spike jitter on the nuclear neuron firing. Additionally, we find that the rate of rebound responses in nuclear neurons after a synchronous pause is controlled by the firing rate of Purkinje neurons preceding it.

  10. The autosomal dominant spinocerebellar ataxias: emerging mechanistic themes suggest pervasive Purkinje cell vulnerability.

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    Hekman, Katherine E; Gomez, Christopher M

    2015-05-01

    The spinocerebellar ataxias are a genetically heterogeneous group of disorders with clinically overlapping phenotypes arising from Purkinje cell degeneration, cerebellar atrophy and varying degrees of degeneration of other grey matter regions. For 22 of the 32 subtypes, a genetic cause has been identified. While recurring themes are emerging, there is no clear correlation between the clinical phenotype or penetrance, the type of genetic defect or the category of the disease mechanism, or the neuronal types involved beyond Purkinje cells. These phenomena suggest that cerebellar Purkinje cells may be a uniquely vulnerable neuronal cell type, more susceptible to a wider variety of genetic/cellular insults than most other neuron types.

  11. Emergence of endoplasmic reticulum stress and activated microglia in Purkinje cell degeneration mice.

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    Kyuhou, Shin-ichi; Kato, Nobuo; Gemba, Hisae

    2006-03-27

    In the current studies, we characterized the molecular and cellular mechanism of cell death in Purkinje cell degeneration (pcd) mice using real-time quantitative PCR, immunohistochemistry, and Western blotting. It appears that endoplasmic reticulum (ER) stress is involved in this degeneration of Purkinje cells because ER stress-related substrates, such as CHOP and caspase 12, were strongly activated in Purkinje cells of pcd mice during the third postnatal (P) week. A significant increase in the expression of the ER-specific chaperone BiP suggested that unfolded protein responses were induced. We also found that Purkinje cells underwent apoptosis via the activation of caspase 3 and subsequent fragmentation of DNA. In addition to the activation of apoptosis in Purkinje cells, many activated microglial cells are found to be present in the molecular layer of the cerebellar cortex. In the later phase of degeneration, there was conspicuous expression of inducible nitric oxide synthase (iNOS), and some Purkinje cells were strongly labeled with an antibody to nitrotyrosine, suggesting that Purkinje cells in pcd mice are damaged by nitric oxide released from microglial cells. Administration of minocycline, which may inhibit iNOS expression, delayed the death of Purkinje cells in pcd mice and mildly improved their motor abilities. These findings suggest that ER stress participates in the degeneration of Purkinje cells and that activation of microglia accelerates Purkinje cell death in pcd mice.

  12. The analysis of purkinje cell dendritic morphology in organotypic slice cultures.

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    Kapfhammer, Josef P; Gugger, Olivia S

    2012-03-21

    Purkinje cells are an attractive model system for studying dendritic development, because they have an impressive dendritic tree which is strictly oriented in the sagittal plane and develops mostly in the postnatal period in small rodents (3). Furthermore, several antibodies are available which selectively and intensively label Purkinje cells including all processes, with anti-Calbindin D28K being the most widely used. For viewing of dendrites in living cells, mice expressing EGFP selectively in Purkinje cells (11) are available through Jackson labs. Organotypic cerebellar slice cultures cells allow easy experimental manipulation of Purkinje cell dendritic development because most of the dendritic expansion of the Purkinje cell dendritic tree is actually taking place during the culture period (4). We present here a short, reliable and easy protocol for viewing and analyzing the dendritic morphology of Purkinje cells grown in organotypic cerebellar slice cultures. For many purposes, a quantitative evaluation of the Purkinje cell dendritic tree is desirable. We focus here on two parameters, dendritic tree size and branch point numbers, which can be rapidly and easily determined from anti-calbindin stained cerebellar slice cultures. These two parameters yield a reliable and sensitive measure of changes of the Purkinje cell dendritic tree. Using the example of treatments with the protein kinase C (PKC) activator PMA and the metabotropic glutamate receptor 1 (mGluR1) we demonstrate how differences in the dendritic development are visualized and quantitatively assessed. The combination of the presence of an extensive dendritic tree, selective and intense immunostaining methods, organotypic slice cultures which cover the period of dendritic growth and a mouse model with Purkinje cell specific EGFP expression make Purkinje cells a powerful model system for revealing the mechanisms of dendritic development.

  13. A signal processing analysis of Purkinje cells in vitro

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    Ze'ev R Abrams

    2010-05-01

    Full Text Available Cerebellar Purkinje cells in vitro fire recurrent sequences of Sodium and Calcium spikes. Here, we analyze the Purkinje cell using harmonic analysis, and our experiments reveal that its output signal is comprised of three distinct frequency bands, which are combined using Amplitude and Frequency Modulation (AM/FM. We find that the three characteristic frequencies - Sodium, Calcium and Switching – occur in various combinations in all waveforms observed using whole-cell current clamp recordings. We found that the Calcium frequency can display a frequency doubling of its frequency mode, and the Switching frequency can act as a possible generator of pauses that are typically seen in Purkinje output recordings. Using a reversibly photo-switchable kainate receptor agonist, we demonstrate the external modulation of the Calcium and Switching frequencies. These experiments and Fourier analysis suggest that the Purkinje cell can be understood as a harmonic signal oscillator, enabling a higher level of interpretation of Purkinje signaling based on modern signal processing techniques.

  14. Differential sensitivity of cerebellar purkinje neurons to ethanol in selectively outbred lines of mice: maintenance in vitro independent of synaptic transmission.

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    Basile, A; Hoffer, B; Dunwiddie, T

    1983-03-28

    The effects of ethanol on spontaneous firing of cerebellar Purkinje neurons were examined in outbred lines of mice (short-sleep, SS; and long-sleep, LS) which exhibit differential behavioral sensitivity to ethanol. In order to determine whether the differences in Purkinje cell ethanol sensitivity which are observed in situ reflect differences in intrinsic properties of Purkinje neurons, we developed an isolated in vitro preparation of mouse cerebellum. Even when synaptic transmission was largely inhibited by elevating Mg2+ and decreasing Ca2+ concentrations, Purkinje cells demonstrated stable long-term firing rates quite similar to those observed in vivo. Purkinje cells responded to superfusion of ethanol with both increases and decreases in firing rate. Inhibition of rate was more commonly observed, and was the only response which was demonstrably dose-dependent. The differential sensitivity to ethanol which we have previously reported in vivo was maintained even under under these conditions, with the LS mice being approximately 5 times more sensitive to the depressant effects of ethanol. In addition, it was shown that ethanol, at the concentrations used in these experiments, decreased the amplitude and increased the duration of single action potentials. Thus, taken together, these results suggest that the differential sensitivity of outbred lines to the soporific effects of ethanol are paralleled by differences in the sensitivity of Purkinje neurons in vitro to superfusion with ethanol. Because these differences can be observed even when synaptic transmission is largely suppressed, it would appear that these differences are intrinsic to the purkinje neurons themselves.

  15. P/Q-type and T-type calcium channels, but not type 3 transient receptor potential cation channels, are involved in inhibition of dendritic growth after chronic metabotropic glutamate receptor type 1 and protein kinase C activation in cerebellar Purkinje cells.

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    Gugger, Olivia S; Hartmann, Jana; Birnbaumer, Lutz; Kapfhammer, Josef P

    2012-01-01

    The development of a neuronal dendritic tree is modulated both by signals from afferent fibers and by an intrinsic program. We have previously shown that chronic activation of either type 1 metabotropic glutamate receptors (mGluR1s) or protein kinase C (PKC) in organotypic cerebellar slice cultures of mice and rats severely inhibits the growth and development of the Purkinje cell dendritic tree. The signaling events linking receptor activation to the regulation of dendritic growth remain largely unknown. We have studied whether channels allowing the entry of Ca(2+) into Purkinje cells, in particular the type 3 transient receptor potential cation channels (TRPC3s), P/Q-type Ca(2+) channels, and T-type Ca(2+) channels, might be involved in signaling after mGluR1 or PKC stimulation. We show that the inhibition of dendritic growth seen after mGluR1 or PKC stimulation is partially rescued by pharmacological blockade of P/Q-type and T-type Ca(2+) channels, indicating that activation of these channels mediating Ca(2+) influx contributes to the inhibition of dendritic growth. In contrast, the absence of Ca(2+) -permeable TRPC3s in TRPC3-deficient mice or pharmacological blockade had no effect on mGluR1-mediated and PKC-mediated inhibition of Purkinje cell dendritic growth. Similarly, blockade of Ca(2+) influx through glutamate receptor δ2 or R-type Ca(2+) channels or inhibition of release from intracellular stores did not influence mGluR1-mediated and PKC-mediated inhibition of Purkinje cell dendritic growth. These findings suggest that both T-type and P/Q-type Ca(2+) channels, but not TRPC3 or other Ca(2+) -permeable channels, are involved in mGluR1 and PKC signaling leading to the inhibition of dendritic growth in cerebellar Purkinje cells.

  16. Increased protein kinase C gamma activity induces Purkinje cell pathology in a mouse model of spinocerebellar ataxia 14.

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    Ji, Jingmin; Hassler, Melanie L; Shimobayashi, Etsuko; Paka, Nagendher; Streit, Raphael; Kapfhammer, Josef P

    2014-10-01

    Spinocerebellar ataxias (SCAs) are hereditary diseases leading to Purkinje cell degeneration and cerebellar dysfunction. Most forms of SCA are caused by expansion of CAG repeats similar to other polyglutamine disorders such as Huntington's disease. In contrast, in the autosomal dominant SCA-14 the disease is caused by mutations in the protein kinase C gamma (PKCγ) gene which is a well characterized signaling molecule in cerebellar Purkinje cells. The study of SCA-14, therefore, offers the unique opportunity to reveal the molecular and pathological mechanism eventually leading to Purkinje cell dysfunction and degeneration. We have created a mouse model of SCA-14 in which PKCγ protein with a mutation found in SCA-14 is specifically expressed in cerebellar Purkinje cells. We find that in mice expressing the mutated PKCγ protein the morphology of Purkinje cells in cerebellar slice cultures is drastically altered and mimics closely the morphology seen after pharmacological PKC activation. Similar morphological abnormalities were seen in localized areas of the cerebellum of juvenile transgenic mice in vivo. In adult transgenic mice there is evidence for some localized loss of Purkinje cells but there is no overall cerebellar atrophy. Transgenic mice show a mild cerebellar ataxia revealed by testing on the rotarod and on the walking beam. Our findings provide evidence for both an increased PKCγ activity in Purkinje cells in vivo and for pathological changes typical for cerebellar disease thus linking the increased and dysregulated activity of PKCγ tightly to the development of cerebellar disease in SCA-14 and possibly also in other forms of SCA.

  17. FGF14 modulates resurgent sodium current in mouse cerebellar Purkinje neurons.

    Science.gov (United States)

    Yan, Haidun; Pablo, Juan L; Wang, Chaojian; Pitt, Geoffrey S

    2014-09-30

    Rapid firing of cerebellar Purkinje neurons is facilitated in part by a voltage-gated Na(+) (NaV) 'resurgent' current, which allows renewed Na(+) influx during membrane repolarization. Resurgent current results from unbinding of a blocking particle that competes with normal channel inactivation. The underlying molecular components contributing to resurgent current have not been fully identified. In this study, we show that the NaV channel auxiliary subunit FGF14 'b' isoform, a locus for inherited spinocerebellar ataxias, controls resurgent current and repetitive firing in Purkinje neurons. FGF14 knockdown biased NaV channels towards the inactivated state by decreasing channel availability, diminishing the 'late' NaV current, and accelerating channel inactivation rate, thereby reducing resurgent current and repetitive spiking. Critical for these effects was both the alternatively spliced FGF14b N-terminus and direct interaction between FGF14b and the NaV C-terminus. Together, these data suggest that the FGF14b N-terminus is a potent regulator of resurgent NaV current in cerebellar Purkinje neurons.

  18. 电鱼小脑浦肯野细胞对急性缺氧的功能反应%Functional responses of mormyrid cerebellar Purkinje cells to acute hypoxia insult

    Institute of Scientific and Technical Information of China (English)

    李晶; 师长宏; 成胜权; 李果; 谭小丽; 杜永平; 张月萍

    2013-01-01

    目的:通过研究急性缺氧对电鱼(mormyrid electric fish)小脑浦肯野细胞(Purkinje cell,PC)的功能影响,阐明缺氧耐受动物神经元在缺氧条件下的电生理特征.方法:采用全细胞膜片钳记录法,观察急性缺氧对电鱼小脑主神经元PC膜电位、兴奋性和平行纤维(parallel fiber,PF)-PC突触传递的影响.结果:(1)短暂缺氧使电鱼小脑PC膜电位发生迅速而持久的超极化,可持续30 min以上,同时伴随自发放电频率的显著下降.谷氨酸AMPA受体阻断剂CNQX不影响PC缺氧性超极化的产生,但可阻断缺氧性超极化的持续存在;而GABAA受体阻断剂Bicuculline则完全阻断缺氧性超极化的产生,并使膜电位在缺氧开始后发生短暂的去极化.(2)缺氧使PC诱发动作电位的阈值增高,频率减低,幅值减小.(3)急性缺氧使刺激PF诱发的PC兴奋性突触后电流(excitatory postsynaptic current,EPSC)呈现长时程增强(long term potentiation,LTP),同时使EPSC双脉冲增强现象(pair-pulse facilitation,PPF)显著衰减.CNQX逆转了PF EPSC的缺氧性LTP,表现为长时程抑制(Long Term Depression,LTD);而Bicuculline则使PF EPSC的缺氧性LTP增强.结论:耐缺氧动物电鱼小脑神经元的缺氧反应特征与哺乳类动物显著不同,AMPA受体和GABAA受体均参与电鱼小脑PC的缺氧性超极化和PF LTP的产生,表明维持GABA能突触和谷氨酸能突触活动的适度平衡,可能是电鱼以及其他耐缺氧动物脑保护机制的关键.%Objective: To evaluate the electrophysiological characteristics of neuron in anorexia tolerant animal under hypoxia condition by discovering the functional responses of Mormyrid cerebellar Purkinje cells (PCs) to acute hypoxia insult. Methods: The whole cell patch clamp was used for the intracellular recording from PCs of the mormyrid cerebellar slices to evaluate the changes of the membrane potential and the excitability of PCs and the PF-PC synaptic transmission induced by acute

  19. Alteration in 5-hydroxymethylcytosine-mediated epigenetic regulation leads to Purkinje cell vulnerability in ATM deficiency.

    Science.gov (United States)

    Jiang, Dewei; Zhang, Ying; Hart, Ronald P; Chen, Jianmin; Herrup, Karl; Li, Jiali

    2015-12-01

    A long-standing mystery surrounding ataxia-telangiectasia is why it is mainly cerebellar neurons, Purkinje cells in particular, that appear vulnerable to ATM deficiency. Here we present data showing that 5-hydroxymethylcytosine (5hmC), a newly recognized epigenetic marker found at high levels in neurons, is substantially reduced in human ataxia-telangiectasia and Atm(-/-) mouse cerebellar Purkinje cells. We further show that TET1, an enzyme that converts 5-methylcytosine (5mC) to 5hmC, responds to DNA damage and manipulation of TET1 activity directly affects the DNA damage signalling and ATM-deficient neuronal cell cycle re-entry and death. Quantitative genome-wide analysis of 5hmC-containing sequences shows that in ATM deficiency there is a cerebellum- and Purkinje cell-specific shift in 5hmC enrichment in both regulatory elements and repeated sequences. Finally, we verify that TET1-mediated 5hmC production is linked to the degenerative process of Purkinje cells and behavioural deficits in Atm(-/-) mice. Taken together, the selective loss of 5hmC plays a critical role in driving Purkinje cell vulnerability in ATM deficiency.

  20. Activation of steroid-sensitive TRPM3 channels potentiates glutamatergic transmission at cerebellar Purkinje neurons from developing rats.

    Science.gov (United States)

    Zamudio-Bulcock, Paula A; Everett, Julie; Harteneck, Christian; Valenzuela, C Fernando

    2011-11-01

    The functional implications of transient receptor potential melastatin 3 (TRPM3) activation, the most recently described member of the melastatin subfamily of cation permeable TRP channels, have begun to be elucidated in recent years. The discovery of TRPM3 activation by the steroid pregnenolone sulfate (PregS) has shed new light on the physiological role of this channel. For example, TRPM3 activation enhances insulin secretion from β pancreatic cells, induces contraction of vascular smooth muscle, and is also involved in the detection of noxious heat. Although TRPM3 expression has been detected in several regions of the developing and mature brain, little is known about the roles of TRPM3 in brain physiology. In this study, we demonstrate the abundant expression of TRPM3 steroid-sensitive channels in the developing cerebellar cortex. We also show that TRPM3-like channels are expressed at glutamatergic synapses in neonatal Purkinje cells. We recently showed that PregS potentiates spontaneous glutamate release onto neonatal Purkinje cells during a period of active glutamatergic synapse formation; we now show that this effect of PregS is mediated by TRPM3-like channels. Mefenamic acid, a recently discovered TRPM3 antagonist, blocked the effect of PregS on glutamate release. The PregS effect on glutamate release was mimicked by other TRPM3 agonists (nifedipine and epipregnanolone sulfate) but not by a TRMP3-inactive steroid (progesterone). Our findings identify TRPM3 channels as novel modulators of glutamatergic transmission in the developing brain.

  1. Action potentials initiate in the axon initial segment and propagate through axon collaterals reliably in cerebellar Purkinje neurons.

    Science.gov (United States)

    Foust, Amanda; Popovic, Marko; Zecevic, Dejan; McCormick, David A

    2010-05-19

    Purkinje neurons are the output cells of the cerebellar cortex and generate spikes in two distinct modes, known as simple and complex spikes. Revealing the point of origin of these action potentials, and how they conduct into local axon collaterals, is important for understanding local and distal neuronal processing and communication. By using a recent improvement in voltage-sensitive dye imaging technique that provided exceptional spatial and temporal resolution, we were able to resolve the region of spike initiation as well as follow spike propagation into axon collaterals for each action potential initiated on single trials. All fast action potentials, for both simple and complex spikes, whether occurring spontaneously or in response to a somatic current pulse or synaptic input, initiated in the axon initial segment. At discharge frequencies of less than approximately 250 Hz, spikes propagated faithfully through the axon and axon collaterals, in a saltatory manner. Propagation failures were only observed for very high frequencies or for the spikelets associated with complex spikes. These results demonstrate that the axon initial segment is a critical decision point in Purkinje cell processing and that the properties of axon branch points are adjusted to maintain faithful transmission.

  2. Estudo estereológico das células de Purkinje cerebelares submetidas à intoxicação alcoólica em ratos Wistar Stereologic study of the cerebellar Purkinje cells submitted to alcoholic intoxication in Wistar rats

    Directory of Open Access Journals (Sweden)

    Mara Ibis Rodrigues Apfel

    2002-06-01

    Full Text Available MOTIVO DO ESTUDO: Analisar o efeito do álcool sobre as células de Purkinje de ratos. MÉTODO: Ratos Wistar receberam oralmente soluções alcoólicas em diferentes concentrações 4%, 12% e 24%. Os animais foram sacrificados com 4, 8 e 12 semanas e os cerebelos foram clivados em cortes aleatórios e uniformemente isotrópicos e incluídos em parafina. Cortes de 6µm (H & E foram analisados por estereologia. RESULTADOS: As diferenças entre a densidade por área e densidade de superfície das células de Purkinje de todos os grupos experimentais (E e os respectivos controles (C foram significativas. Com 12 semanas, a densidade volumétrica da célula de Purkinje diminuiu entre os grupos C e E nas concentrações de 4% e 12%, mas não para a concentração de 24%, provavelmente devido a menor ingestão de líquido pelos animais. CONCLUSÃO: O álcool exerceu efeito tóxico sobre o corpo celular da célula de Purkinje nas três concentrações estudadas a partir de 4 semanas.BACKGROUND: to analyze the effect of the alcohol on the cells of Purkinje. METHOD: Wistar rats received alcoholic solutions orally in different concentrations 4%, 12% and 24%. The animals were sacrificed with 4, 8 and 12 weeks and the cerebella were randomly cut and embedded in paraffin. Sections of 6µm (H&E were stereologically analyzed. RESULTS: The differences among the density for area and density of surface of the cells of Purkinje of all of the experimental groups (E and the respective controls (C were significant. With 12 weeks the cell of Purkinje volume density decreased among the groups C and E in the concentrations of 4% and 12%, but not for the concentration of 24%, probably due to smaller liquid ingestion by the animals. CONCLUSION: The alcohol has toxic effect on the Purkinje cellular body in the three studied concentrations from 4 weeks.

  3. Activity-dependent accumulation of calcium in Purkinje cell dendritic spines.

    OpenAIRE

    Andrews, S.B.; Leapman, R D; Landis, D M; Reese, T S

    1988-01-01

    The calcium content of synapses of parallel fibers on Purkinje cell dendritic spines was determined by electron probe x-ray microanalysis of freeze-dried cryosections from directly frozen slices of mouse cerebellar cortex. In fresh slices frozen within 20-30 sec of excision, calcium concentrations ranging from 0.8 to 18.6 mmol/kg of dry weight were measured in cisterns of smooth endoplasmic reticulum within Purkinje cell dendritic spines. The average calcium content of spine cisterns in rapid...

  4. Temporal effects of thyroid hormone (TH) and decabrominated diphenyl ether (BDE209) on Purkinje cell dendrite arborization.

    Science.gov (United States)

    Ibhazehiebo, K; Koibuchi, N

    2012-06-07

    Thyroid hormones (TH) 3,3',4-tri-iodothyronine (T3) and 3,3',4,4'-tetra-iodothyronine (T4) plays crucial role in cerebellar development. Deficiency of TH consistently results in aberrant growth and development of the cerebellum including reduced growth and branching of the Purkinje cells. In rodents, the critical period of thyroid hormone action on cerebellum development is within the first two to three weeks, after which thyroid hormone replacement cannot fully reverse abnormal cerebellar development induced by thyroid hormone insult. Decabrominated diphenyl ether (BDE209) is an industrial reagent used as an additive flame retardant to reduce flammability of various commercial and household produce. BDE209 has bio-accumulative potential and is neurotoxic. Previously, we have shown that T4 (10-8 M) induced extensive dendrite arborization of Purkinje cells and low dose BDE209 (10-10 M) remarkably suppressed TH-induced Purkinje cell dendrite arborization. In the present study, we show that the critical period for TH-induced Purkinje cell growth and dendrite arborization in culture is much earlier than reported in animal models. Also, we show for the first time that low dose BDE209 suppressed TH-induced dendrite arborization in a time-dependent manner. Taken together, our study indicates that hypothyroidism and exposure to BDE209 during critical stage of cerebellar development can lead to impaired Purkinje cell growth and dendrite arborization and may consequently disrupt normal cerebellar functions.

  5. Deranged calcium signaling in Purkinje cells and pathogenesis in spinocerebellar ataxia 2 (SCA2) and other ataxias.

    Science.gov (United States)

    Kasumu, Adebimpe; Bezprozvanny, Ilya

    2012-09-01

    Spinocerebellar ataxias (SCAs) constitute a heterogeneous group of more than 30 autosomal-dominant genetic and neurodegenerative disorders. SCAs are generally characterized by progressive ataxia and cerebellar atrophy. Although all SCA patients present with the phenotypic overlap of cerebellar atrophy and ataxia, 17 different gene loci have so far been implicated as culprits in these SCAs. It is not currently understood how mutations in these 17 proteins lead to the cerebellar atrophy and ataxia. Several pathogenic mechanisms have been studied in SCAs but there is yet to be a promising target for successful treatment of SCAs. Emerging research suggests that a fundamental cellular signaling pathway is disrupted by a majority of these mutated genes, which could explain the characteristic death of Purkinje cells, cerebellar atrophy, and ataxia that occur in many SCAs. We propose that mutations in SCA genes cause disruptions in multiple cellular pathways but the characteristic SCA pathogenesis does not begin until calcium signaling pathways are disrupted in cerebellar Purkinje cells either as a result of an excitotoxic increase or a compensatory suppression of calcium signaling. We argue that disruptions in Purkinje cell calcium signaling lead to initial cerebellar dysfunction and ataxic sympoms and eventually proceed to Purkinje cell death. Here, we discuss a calcium hypothesis of Purkinje cell neurodegeneration in SCAs by primarily focusing on an example of spinocerebellar ataxia 2 (SCA2). We will also present evidence linking deranged calcium signaling to the pathogenesis of other SCAs (SCA1, 3, 5, 6, 14, 15/16) that lead to significant Purkinje cell dysfunction and loss in patients.

  6. Voltage-dependent potassium currents during fast spikes of rat cerebellar Purkinje neurons: inhibition by BDS-I toxin.

    Science.gov (United States)

    Martina, Marco; Metz, Alexia E; Bean, Bruce P

    2007-01-01

    We characterized the kinetics and pharmacological properties of voltage-activated potassium currents in rat cerebellar Purkinje neurons using recordings from nucleated patches, which allowed high resolution of activation and deactivation kinetics. Activation was exceptionally rapid, with 10-90% activation in about 400 mus at +30 mV, near the peak of the spike. Deactivation was also extremely rapid, with a decay time constant of about 300 mus near -80 mV. These rapid activation and deactivation kinetics are consistent with mediation by Kv3-family channels but are even faster than reported for Kv3-family channels in other neurons. The peptide toxin BDS-I had very little blocking effect on potassium currents elicited by 100-ms depolarizing steps, but the potassium current evoked by action potential waveforms was inhibited nearly completely. The mechanism of inhibition by BDS-I involves slowing of activation rather than total channel block, consistent with the effects described in cloned Kv3-family channels and this explains the dramatically different effects on currents evoked by short spikes versus voltage steps. As predicted from this mechanism, the effects of toxin on spike width were relatively modest (broadening by roughly 25%). These results show that BDS-I-sensitive channels with ultrafast activation and deactivation kinetics carry virtually all of the voltage-dependent potassium current underlying repolarization during normal Purkinje cell spikes.

  7. Kv3.3 channels at the Purkinje cell soma are necessary for generation of the classical complex spike waveform.

    Science.gov (United States)

    Zagha, Edward; Lang, Eric J; Rudy, Bernardo

    2008-02-06

    Voltage-gated potassium channel subunit Kv3.3 is prominently expressed in cerebellar Purkinje cells and is known to be important for cerebellar function, as human and mouse movement disorders result from mutations in Kv3.3. To understand these behavioral deficits, it is necessary to know the role of Kv3.3 channels on the physiological responses of Purkinje cells. We studied the function of Kv3.3 channels in regulating the synaptically evoked Purkinje cell complex spike, the massive postsynaptic response to the activation of climbing fiber afferents, believed to be fundamental to cerebellar physiology. Acute slice recordings revealed that Kv3.3 channels are required for generation of the repetitive spikelets of the complex spike. We found that spikelet expression is regulated by somatic, and not by dendritic, Kv3 activity, which is consistent with dual somatic-dendritic recordings that demonstrate spikelet generation at axosomatic membranes. Simulations of Purkinje cell Na+ currents show that the unique electrical properties of Kv3 and resurgent Na+ channels are coordinated to limit accumulation of Na+ channel inactivation and enable rapid, repetitive firing. We additionally show that Kv3.3 knock-out mice produce altered complex spikes in vitro and in vivo, which is likely a cellular substrate of the cerebellar phenotypes observed in these mice. This characterization presents new tools to study complex spike function, cerebellar signaling, and Kv3.3-dependent human and mouse phenotypes.

  8. Computational analysis of calcium signaling and membrane electrophysiology in cerebellar Purkinje neurons associated with ataxia

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    Brown Sherry-Ann

    2012-06-01

    Full Text Available Abstract Background Mutations in the smooth endoplasmic reticulum (sER calcium channel Inositol Trisphosphate Receptor type 1 (IP3R1 in humans with the motor function coordination disorders Spinocerebellar Ataxia Types 15 and 16 (SCA15/16 and in a corresponding mouse model, the IP3R1delta18/delta18 mice, lead to reduced IP3R1 levels. We posit that increasing IP3R1 sensitivity to IP3 in ataxias with reduced IP3R1 could restore normal calcium response. On the other hand, in mouse models of the human polyglutamine (polyQ ataxias, SCA2, and SCA3, the primary finding appears to be hyperactive IP3R1-mediated calcium release. It has been suggested that the polyQ SCA1 mice may also show hyperactive IP3R1. Yet, SCA1 mice show downregulated gene expression of IP3R1, Homer, metabotropic glutamate receptor (mGluR, smooth endoplasmic reticulum Ca-ATP-ase (SERCA, calbindin, parvalbumin, and other calcium signaling proteins. Results We create a computational model of pathological alterations in calcium signaling in cerebellar Purkinje neurons to investigate several forms of spinocerebellar ataxia associated with changes in the abundance, sensitivity, or activity of the calcium channel IP3R1. We find that increasing IP3R1 sensitivity to IP3 in computational models of SCA15/16 can restore normal calcium response if IP3R1 abundance is not too low. The studied range in IP3R1 levels reflects variability found in human and mouse ataxic models. Further, the required fold increases in sensitivity are within experimental ranges from experiments that use IP3R1 phosphorylation status to adjust its sensitivity to IP3. Results from our simulations of polyglutamine SCAs suggest that downregulation of some calcium signaling proteins may be partially compensatory. However, the downregulation of calcium buffer proteins observed in the SCA1 mice may contribute to pathology. Finally, our model suggests that the calcium-activated voltage-gated potassium channels may provide an

  9. IgG from Amyotrophic Lateral Sclerosis Patients Increases Current Through P-Type Calcium Channels in Mammalian Cerebellar Purkinje Cells and in Isolated Channel Protein in Lipid Bilayer

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    Llinas, R.; Sugimori, M.; Cherksey, B. D.; Smith, R. Glenn; Delbono, O.; Stefani, E.; Appel, S.

    1993-12-01

    The effect of the IgG from amyotrophic lateral sclerosis (ALS) patients was tested on the voltage-dependent barium currents (IBa) in mammalian dissociated Purkinje cells and in isolated P-type calcium channels in lipid bilayers. Whole cell clamp of Purkinje cells demonstrates that ALS IgG increases the amplitude of IBa without modifying their voltage kinetics. This increased IBa could be blocked by a purified nonpeptide toxin from Agelenopsis aperta venom (purified funnel-web spider toxin) or by a synthetic polyamine analog (synthetic funnel-web spider toxin) and by a peptide toxin from the same spider venom, ω-Aga-IVA. Similar results were obtained on single-channel recordings from purified P channel protein. The addition of ALS IgG increased single-channel IBa open time without affecting slope conductance. The results described above were not seen with normal human IgG nor with boiled ALS IgG. It is concluded that ALS IgG enhances inward current through P-type calcium channels. Since P-type Ca2+ channels are present in motoneuron axon terminals, we propose that the enhanced calcium current triggered by ALS IgG may contribute to neuronal damage in ALS.

  10. A new approach for determining phase response curves reveals that Purkinje cells can act as perfect integrators.

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    Elena Phoka

    2010-04-01

    Full Text Available Cerebellar Purkinje cells display complex intrinsic dynamics. They fire spontaneously, exhibit bistability, and via mutual network interactions are involved in the generation of high frequency oscillations and travelling waves of activity. To probe the dynamical properties of Purkinje cells we measured their phase response curves (PRCs. PRCs quantify the change in spike phase caused by a stimulus as a function of its temporal position within the interspike interval, and are widely used to predict neuronal responses to more complex stimulus patterns. Significant variability in the interspike interval during spontaneous firing can lead to PRCs with a low signal-to-noise ratio, requiring averaging over thousands of trials. We show using electrophysiological experiments and simulations that the PRC calculated in the traditional way by sampling the interspike interval with brief current pulses is biased. We introduce a corrected approach for calculating PRCs which eliminates this bias. Using our new approach, we show that Purkinje cell PRCs change qualitatively depending on the firing frequency of the cell. At high firing rates, Purkinje cells exhibit single-peaked, or monophasic PRCs. Surprisingly, at low firing rates, Purkinje cell PRCs are largely independent of phase, resembling PRCs of ideal non-leaky integrate-and-fire neurons. These results indicate that Purkinje cells can act as perfect integrators at low firing rates, and that the integration mode of Purkinje cells depends on their firing rate.

  11. Early hypergravity exposure effects calbindin-D28k and inositol-3-phosphate expression in Purkinje cells

    NARCIS (Netherlands)

    Bouet, [No Value; Dijk, F; Ijkema-Paassen, J; Wubbels, RJ; van der Want, JJ; Gramsbergen, A

    2005-01-01

    In this study the effects of hypergravity were analyzed on cerebellar Purkinje cells during early development in rats. The cerebellum is a key structure in the control and the adaptation of posture and anti-gravity activities. This holds particularly when external conditions are modified. Three grou

  12. Transient developmental Purkinje cell axonal torpedoes in healthy and ataxic mouse cerebellum

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    Lovisa Ljungberg

    2016-11-01

    Full Text Available Information is carried out of the cerebellar cortical microcircuit via action potentials propagated along Purkinje cell axons. In several human neurodegenerative diseases, focal axonal swellings on Purkinje cells – known as torpedoes – have been associated with Purkinje cell loss. Interestingly, torpedoes are also reported to appear transiently during development in rat cerebellum. The function of Purkinje cell axonal torpedoes in health as well as in disease is poorly understood. We investigated the properties of developmental torpedoes in the postnatal mouse cerebellum of wildtype and transgenic mice. We found that Purkinje cell axonal torpedoes transiently appeared on axons of Purkinje neurons, with the largest number of torpedoes observed at postnatal day 11 (P11. This was after peak developmental apoptosis had occurred, when Purkinje cell counts in a lobule were static, suggesting that most developmental torpedoes appear on axons of neurons that persist into adulthood. We found that developmental torpedoes were not associated with a presynaptic GABAergic marker, indicating that they are not synapses. They were seldom found at axonal collateral branch points, and lacked microglia enrichment, suggesting that they are unlikely to be involved in axonal refinement. Interestingly, we found several differences between developmental torpedoes and disease-related torpedoes: developmental torpedoes occured largely on myelinated axons, and were not associated with changes in basket cell innervation on their parent soma. Disease-related torpedoes are typically reported to contain neurofilament; while the majority of developmental torpedoes did as well, a fraction of smaller developmental torpedoes did not. These differences indicate that developmental torpedoes may not be functionally identical to disease-related torpedoes. To study this further, we used a mouse model of spinocerebellar ataxia type 6 (SCA6, and found elevated disease

  13. The ins and outs of GluD2--why and how Purkinje cells use the special glutamate receptor.

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    Yuzaki, Michisuke

    2012-06-01

    The δ2 glutamate receptor (GluD2) is predominantly expressed in cerebellar Purkinje cells and plays crucial roles in cerebellar functions. Indeed, the number of synapses between parallel fibers (PFs) and Purkinje cells is specifically and severely reduced in GluD2-null cerebellum. In addition, long-term depression (LTD) at PF-Purkinje cell synapses is impaired in these mice. Nevertheless, the mechanism by which GluD2 regulate these two functions-morphological and functional synaptic plasticity at PF synapses-has remained unclear. Recently, we found that Cbln1, a glycoprotein released from granule cells, was bound to the N-terminal domain of GluD2 and regulated formation and maintenance of PF-Purkinje cell synapses. Furthermore, we found that D: -Ser released from Bergmann glia bound the ligand-binding domain of GluD2 and mediated LTD in a manner dependent on the C-terminus. These findings indicate how GluD2 is activated and regulates functions at PF-Purkinje cell synapses. A hypothesis about why GluD2 is employed by PF synapses is also discussed.

  14. Uneven distribution of NG2 cells in the rat cerebellar vermis and changes in aging

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    S. Lomoio

    2012-06-01

    Full Text Available We describe by NG2 (neuron-glia chondroitin sulphate proteoglycan 2 immunocytochemistry an uneven distribution of NG2 glial cells in the rat cerebellum, being them more represented in the central lobules of the cerebellar vermis, belonging to the cerebrocerebellum. The cerebellar distribution of NG2 cells changes in aging rats, in which the area where the cells appear to be densely scattered throughout all cerebellar layers involves also more rostral and caudal lobules. In addition, in aging rats, in the most rostral and caudal lobules belonging to the spinocerebellum, punctate reaction product is present at the apical pole of Purkinje cells, i.e. in the area where the majority of synapses between olivary climbing fibers and Purkinje cells occur. Data suggest that the different distribution of NG2 cells is correlated to differences in physiology among cerebellar areas and reflects changes during aging.

  15. Uneven distribution of NG2 cells in the rat cerebellar vermis and changes in aging

    Science.gov (United States)

    Lomoio, S.; Necchi, D.; Scherini, E.

    2012-01-01

    We describe by NG2 (neuron-glia chondroitin sulphate proteoglycan 2) immunocytochemistry an uneven distribution of NG2 glial cells in the rat cerebellum, being them more represented in the central lobules of the cerebellar vermis, belonging to the cerebrocerebellum. The cerebellar distribution of NG2 cells changes in aging rats, in which the area where the cells appear to be densely scattered throughout all cerebellar layers involves also more rostral and caudal lobules. In addition, in aging rats, in the most rostral and caudal lobules belonging to the spinocerebellum, punctate reaction product is present at the apical pole of Purkinje cells, i.e. in the area where the majority of synapses between olivary climbing fibers and Purkinje cells occur. Data suggest that the different distribution of NG2 cells is correlated to differences in physiology among cerebellar areas and reflects changes during aging. PMID:23027343

  16. Effects of Chronic Ethanol Intoxication on the Ultrastructures of Cerebellar Purkinje Cells in Adult Mice%慢性酒精中毒对成年小鼠小脑浦肯野细胞超微结构的影响

    Institute of Scientific and Technical Information of China (English)

    张长征; 朱庆丰

    2011-01-01

    目的 观察慢性酒精中毒所致的成年小鼠小脑皮质浦肯野细胞(Purkinje cell,PC)胞体的超微结构变化,探讨其对神经元超微结构的影响方式及生理意义.方法 用15%酒精饲喂3月龄小白鼠3个月,经行为学检测后,取小脑前叶做电镜包埋,切片,染色,透射电镜下观察并拍照.结果 酒精中毒组PC核周质中线粒体膨解,基质囊泡化;高尔基复合体扁平囊扩张;粗面内质网碎裂,核糖体颗粒减少;"空泡变性"出现;双层核膜界限不清;染色质边集等变化.结论 慢性酒精中毒可导致小脑浦肯野细胞多种细胞器出现异常改变,推测这些变化可引起胞内物质合成减少,空间构筑紊乱,神经元死亡,最终导致小脑功能损伤.%Objective We observed chronic ethanol-induced ultrastructural alterations of Purkinje cell (PC) somata in the mouse cerebellar cortex, in order to explore the manner of ethanol impacts on neuronal ultrastructures and the physiological influences underlying these alterations. Methods 3-month old mice were fed with 15% alcohol for 3 months. After the behavioral test to manifest the symptoms of ethanol intoxication, the anterior lobe from each mouse cerebellum was selected for embedding , sectioning, and staining. Undera transmission electron microscope, the organelles of PC somata were observed and photos were taken. Results The organelles in ethanol-intoxicated PCs exhibited the following changes: the mitochondria swelled and the matrix decomposed; the sacs of Golgi apparatus dilated; the rough endoplasmic reticulum (rER) collapsed, accompanied with a great loss of the ribosomes; the "vacuolation" emerged;the double nuclear membrane became illegible; and the chromatin marginally condensed in the nucleus.Conclusion Chronic ethanol intoxication induces degenerative alterations in the organelles of cerebellar PCs, which might result in the decrease in substance synthesis, the disorder in intraneuronal configuration, the

  17. The role of Cbln1 on Purkinje cell synapse formation.

    Science.gov (United States)

    Ito-Ishida, Aya; Okabe, Shigeo; Yuzaki, Michisuke

    2014-06-01

    Cbln1 is a glycoprotein which belongs to the C1q family. In the cerebellum, Cbln1 is produced and secreted from granule cells and works as a strong synapse organizer between Purkinje cells and parallel fibers, the axons of the granule cells. In this update article, we will describe the molecular mechanisms by which Cbln1 induces synapse formation and will review our findings on the axonal structural changes which occur specifically during this process. We will also describe our recent finding that Cbln1 has a suppressive role in inhibitory synapse formation between Purkinje cells and molecular layer interneurons. Our results have revealed that Cbln1 plays an essential role to establish parallel fiber-Purkinje cell synapses and to regulate balance between excitatory and inhibitory input on Purkinje cells.

  18. Dynamic distribution and stem cell characteristics of Sox1-expressing cells in the cerebellar cortex

    Institute of Scientific and Technical Information of China (English)

    Joelle Alcock; Virginie Sottile

    2009-01-01

    Bergmann glia cells are a discrete radial glia population surrounding Purkinje cells in the cerebellar cortex. Al-though Bergmann glia are essential for the development and correct arborization of Purkinje cells, little is known about the regulation of this cell population after the developmental phase. In an effort to characterize this population at the molecular level, we have analyzed marker expression and established that adult Bergmann glia express Soxl, Sox2 and Sox9, a feature otherwise associated with neural stem cells (NSCs). In the present study, we have further analyzed the developmental pattern of Soxl-expressing cells in the developing cerebellum. We report that before be-coming restricted to the Purkinje cell layer, Soxl-positive cells are present throughout the immature tissue, and that these cells show characteristics of Bergmann glia progenitors. Our study shows that these progenitors express Soxl, Sox2 and Sox9, a signature maintained throughout cerebellar maturation into adulthood. When isolated in culture, the Soxl-expressing cerebellar population exhibited neurosphere-forming ability, NSC-marker characteristics, and demonstrated multipotency at the clonal level. Our results show that the Bergmann glia population expresses Soxl during cerebellar development, and that these cells can be isolated and show stem cell characteristics in vitro, sug-gesting that they could hold a broader potential than previously thought.

  19. Molecular mechanism of parallel fiber-Purkinje cell synapse formation.

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    Mishina, Masayoshi; Uemura, Takeshi; Yasumura, Misato; Yoshida, Tomoyuki

    2012-01-01

    The cerebellum receives two excitatory afferents, the climbing fiber (CF) and the mossy fiber-parallel fiber (PF) pathway, both converging onto Purkinje cells (PCs) that are the sole neurons sending outputs from the cerebellar cortex. Glutamate receptor δ2 (GluRδ2) is expressed selectively in cerebellar PCs and localized exclusively at the PF-PC synapses. We found that a significant number of PC spines lack synaptic contacts with PF terminals and some of residual PF-PC synapses show mismatching between pre- and postsynaptic specializations in conventional and conditional GluRδ2 knockout mice. Studies with mutant mice revealed that in addition to PF-PC synapse formation, GluRδ2 is essential for synaptic plasticity, motor learning, and the restriction of CF territory. GluRδ2 regulates synapse formation through the amino-terminal domain, while the control of synaptic plasticity, motor learning, and CF territory is mediated through the carboxyl-terminal domain. Thus, GluRδ2 is the molecule that bridges synapse formation and motor learning. We found that the trans-synaptic interaction of postsynaptic GluRδ2 and presynaptic neurexins (NRXNs) through cerebellin 1 (Cbln1) mediates PF-PC synapse formation. The synaptogenic triad is composed of one molecule of tetrameric GluRδ2, two molecules of hexameric Cbln1 and four molecules of monomeric NRXN. Thus, GluRδ2 triggers synapse formation by clustering four NRXNs. These findings provide a molecular insight into the mechanism of synapse formation in the brain.

  20. Molecular mechanism of parallel fiber-Purkinje cell synapse formation

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    Masayoshi eMishina

    2012-11-01

    Full Text Available The cerebellum receives two excitatory afferents, the climbing fiber (CF and the mossy fiber-parallel fiber (PF pathway, both converging onto Purkinje cells (PCs that are the sole neurons sending outputs from the cerebellar cortex. Glutamate receptor δ2 (GluRδ2 is expressed selectively in cerebellar PCs and localized exclusively at the PF-PC synapses. We found that a significant number of PC spines lack synaptic contacts with PF terminals and some of residual PF-PC synapses show mismatching between pre- and postsynaptic specializations in conventional and conditional GluRδ2 knockout mice. Studies with mutant mice revealed that in addition to PF-PC synapse formation, GluRδ2 is essential for synaptic plasticity, motor learning and the restriction of CF territory. GluRδ2 regulates synapse formation through the amino-terminal domain, while the control of synaptic plasticity, motor learning and CF territory is mediated through the carboxyl-terminal domain. Thus, GluRδ2 is the molecule that bridges synapse formation and motor learning. We found that the trans-synaptic interaction of postsynaptic GluRδ2 and presynaptic neurexins (NRXNs through Cbln1 mediates PF-PC synapse formation. The synaptogenic triad is composed of one molecule of tetrameric GluRδ2, two molecules of hexameric Cbln1 and four molecules of monomeric NRXN. Thus, GluRδ2 triggers synapse formation by clustering four NRXNs. These findings provide a molecular insight into the mechanism of synapse formation in the brain.

  1. Systematic regional variations in Purkinje cell spiking patterns.

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    Jianqiang Xiao

    Full Text Available In contrast to the uniform anatomy of the cerebellar cortex, molecular and physiological studies indicate that significant differences exist between cortical regions, suggesting that the spiking activity of Purkinje cells (PCs in different regions could also show distinct characteristics. To investigate this possibility we obtained extracellular recordings from PCs in different zebrin bands in crus IIa and vermis lobules VIII and IX in anesthetized rats in order to compare PC firing characteristics between zebrin positive (Z+ and negative (Z- bands. In addition, we analyzed recordings from PCs in the A2 and C1 zones of several lobules in the posterior lobe, which largely contain Z+ and Z- PCs, respectively. In both datasets significant differences in simple spike (SS activity were observed between cortical regions. Specifically, Z- and C1 PCs had higher SS firing rates than Z+ and A2 PCs, respectively. The irregularity of SS firing (as assessed by measures of interspike interval distribution was greater in Z+ bands in both absolute and relative terms. The results regarding systematic variations in complex spike (CS activity were less consistent, suggesting that while real differences can exist, they may be sensitive to other factors than the cortical location of the PC. However, differences in the interactions between SSs and CSs, including the post-CS pause in SSs and post-pause modulation of SSs, were also consistently observed between bands. Similar, though less strong trends were observed in the zonal recordings. These systematic variations in spontaneous firing characteristics of PCs between zebrin bands in vivo, raises the possibility that fundamental differences in information encoding exist between cerebellar cortical regions.

  2. Ataxia and Purkinje cell degeneration in mice lacking the CAMTA1 transcription factor

    Science.gov (United States)

    Long, Chengzu; Grueter, Chad E.; Song, Kunhua; Qin, Song; Qi, Xiaoxia; Kong, Y. Megan; Shelton, John M.; Richardson, James A.; Zhang, Chun-Li; Bassel-Duby, Rhonda; Olson, Eric N.

    2014-01-01

    Members of the calmodulin-binding transcription activator (CAMTA) family of proteins function as calcium-sensitive regulators of gene expression in multicellular organisms ranging from plants to humans. Here, we show that global or nervous system deletion of CAMTA1 in mice causes severe ataxia with Purkinje cell degeneration and cerebellar atrophy, partially resembling the consequences of haploinsufficiency of the human CAMTA1 locus. Gene-expression analysis identified a large collection of neuronal genes that were dysregulated in the brains of CAMTA1-mutant mice, and elucidation of a consensus sequence for binding of CAMTA proteins to DNA revealed the association of CAMTA-binding sites with many of these genes. We conclude that CAMTA1 plays an essential role in the control of Purkinje cell function and survival. CAMTA1-mutant mice provide a model to study the molecular mechanisms of neurodegenerative diseases and for screening potential therapeutic interventions for such disorders. PMID:25049392

  3. Activation of a Temporal Memory in Purkinje Cells by the mGluR7 Receptor

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    Fredrik Johansson

    2015-12-01

    Full Text Available Cerebellar Purkinje cells can learn to respond to a conditioned stimulus with an adaptively timed pause in firing. This response was usually ascribed to long-term depression of parallel fiber to Purkinje cell synapses but has recently been shown to be due to a previously unknown form of learning involving an intrinsic cellular timing mechanism. Here, we investigate how these responses are elicited. They are resistant to blockade of GABAergic inhibition, suggesting that they are caused by glutamate release rather than by a changed balance between GABA and glutamate. We show that the responses are abolished by antagonists of the mGlu7 receptor but not significantly affected by other glutamate antagonists. These results support the existence of a distinct learning mechanism, different from changes in synaptic strength. They also demonstrate in vivo post-synaptic inhibition mediated by glutamate and show that the mGlu7 receptor is involved in activating intrinsic temporal memory.

  4. Cadm1-expressing synapses on Purkinje cell dendrites are involved in mouse ultrasonic vocalization activity.

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    Eriko Fujita

    Full Text Available Foxp2(R552H knock-in (KI mouse pups with a mutation related to human speech-language disorders exhibit poor development of cerebellar Purkinje cells and impaired ultrasonic vocalization (USV, a communication tool for mother-offspring interactions. Thus, human speech and mouse USV appear to have a Foxp2-mediated common molecular basis in the cerebellum. Mutations in the gene encoding the synaptic adhesion molecule CADM1 (RA175/Necl2/SynCAM1/Cadm1 have been identified in people with autism spectrum disorder (ASD who have impaired speech and language. In the present study, we show that both Cadm1-deficient knockout (KO pups and Foxp2(R552H KI pups exhibit impaired USV and smaller cerebellums. Cadm1 was preferentially localized to the apical-distal portion of the dendritic arbor of Purkinje cells in the molecular layer of wild-type pups, and VGluT1 level decreased in the cerebellum of Cadm1 KO mice. In addition, we detected reduced immunoreactivity of Cadm1 and VGluT1 on the poorly developed dendritic arbor of Purkinje cells in the Foxp2(R552H KI pups. However, Cadm1 mRNA expression was not altered in the Foxp2(R552H KI pups. These results suggest that although the Foxp2 transcription factor does not target Cadm1, Cadm1 at the synapses of Purkinje cells and parallel fibers is necessary for USV function. The loss of Cadm1-expressing synapses on the dendrites of Purkinje cells may be associated with the USV impairment that Cadm1 KO and Foxp2(R552H KI mice exhibit.

  5. Oxygen-glucose deprivation increases firing of unipolar brush cells and enhances spontaneous EPSCs in Purkinje cells in the vestibulo-cerebellum.

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    Takayasu, Yukihiro; Shino, Masato; Nikkuni, Osamu; Yoshida, Yukari; Furuya, Nobuhiko; Chikamatsu, Kazuaki

    2016-05-01

    Unipolar brush cells (UBCs) are excitatory interneurons in the granular layer of the cerebellar cortex, which are predominantly distributed in the vestibulo-cerebellar region. The unique firing properties and synaptic connections of UBCs may underlie lobular heterogeneity of excitability in the granular layer and the susceptibility to ischemia-induced excitotoxicity. In this study, we investigated the effects of oxygen-glucose deprivation (OGD) on the firing properties of UBCs and granule cells and spontaneous excitatory postsynaptic currents (sEPSCs) of Purkinje cells using whole-cell recordings. Short-term OGD induced increases in spontaneous firing of UBCs by causing membrane depolarization via the activation of NMDA receptors. UBC firing indirectly affected Purkinje cells by altering parallel fiber inputs of a subset granule cells, resulting in a marked increase in sEPSCs in Purkinje cells in vestibulo-cerebellar lobules IX-X, but not in lobules IV-VI, which have fewer UBCs. Similarly, the frequency and amplitude of sEPSCs in Purkinje cells were significantly greater in lobules IX-X than in IV-VI, even in control conditions. These results reveal that UBCs play key roles in regulating local excitability in the granular layer, resulting in lobular heterogeneity in the susceptibility to ischemic insult in the cerebellum.

  6. Sensory-Driven Enhancement of Calcium Signals in Individual Purkinje Cell Dendrites of Awake Mice

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    Farzaneh Najafi

    2014-03-01

    Full Text Available Climbing fibers (CFs are thought to contribute to cerebellar plasticity and learning by triggering a large influx of dendritic calcium in the postsynaptic Purkinje cell (PC to signal the occurrence of an unexpected sensory event. However, CFs fire about once per second whether or not an event occurs, raising the question of how sensory-driven signals might be distinguished from a background of ongoing spontaneous activity. Here, we report that in PC dendrites of awake mice, CF-triggered calcium signals are enhanced when the trigger is a sensory event. In addition, we show that a large fraction of the total enhancement in each PC dendrite can be accounted for by an additional boost of calcium provided by sensory activation of a non-CF input. We suggest that sensory stimulation may modulate dendritic voltage and calcium concentration in PCs to increase the strength of plasticity signals during cerebellar learning.

  7. Self-Organization of Polarized Cerebellar Tissue in 3D Culture of Human Pluripotent Stem Cells

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    Keiko Muguruma

    2015-02-01

    Full Text Available During cerebellar development, the main portion of the cerebellar plate neuroepithelium gives birth to Purkinje cells and interneurons, whereas the rhombic lip, the germinal zone at its dorsal edge, generates granule cells and cerebellar nuclei neurons. However, it remains elusive how these components cooperate to form the intricate cerebellar structure. Here, we found that a polarized cerebellar structure self-organizes in 3D human embryonic stem cell (ESC culture. The self-organized neuroepithelium differentiates into electrophysiologically functional Purkinje cells. The addition of fibroblast growth factor 19 (FGF19 promotes spontaneous generation of dorsoventrally polarized neural-tube-like structures at the level of the cerebellum. Furthermore, addition of SDF1 and FGF19 promotes the generation of a continuous cerebellar plate neuroepithelium with rhombic-lip-like structure at one end and a three-layer cytoarchitecture similar to the embryonic cerebellum. Thus, human-ESC-derived cerebellar progenitors exhibit substantial self-organizing potential for generating a polarized structure reminiscent of the early human cerebellum at the first trimester.

  8. Low in situ expression of antioxidative enzymes in rat cerebellar granular cells susceptible to methylmercury.

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    Fujimura, M; Usuki, F

    2014-01-01

    Methylmercury (MeHg), an environmental neurotoxicant, induces site-specific toxicity in the brain. Although oxidative stress has been demonstrated with MeHg toxicity, the site-specific toxicity is not completely understood. Among the cerebellar neurons, cerebellar granule cells (CGCs) appear vulnerable to MeHg, whereas Purkinje cells and molecular layer neurons are resistant. Here, we use a MeHg-intoxicated rat model to investigate these cerebellar neurons for the different causes of susceptibility to MeHg. Rats were exposed to 20 ppm MeHg for 4 weeks and subsequently exhibited neuropathological changes in the cerebellum that were similar to those observed in humans. We first isolated the three cerebellar neuron types using a microdissection system and then performed real-time PCR analyses for antioxidative enzymes. We observed that expression of manganese-superoxide dismutase (Mn-SOD), glutathione peroxidase 1 (GPx1), and thioredoxin reductase 1 (TRxR1) was significantly higher in Purkinje cells and molecular layer neurons than in CGCs. Finally, we performed immunohistochemical analyses on the cerebellum. Immunohistochemistry showed increased expression of Mn-SOD, GPx1, and TRxR1 in Purkinje cells and molecular layer neurons, which was coincident with the mRNA expression patterns. Considering Mn-SOD, GPx1, and TRxR1 are critical for protecting cells against MeHg intoxication, the results indicate that low expression of these antioxidative enzymes increases CGCs vulnerability to MeHg toxicity.

  9. Parallel fiber to Purkinje cell synaptic impairment in a mouse model of spinocerebellar ataxia type 27

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    Filippo eTempia

    2015-06-01

    Full Text Available Genetically inherited mutations in the fibroblast growth factor 14 (FGF14 gene lead to spinocerebellar ataxia type 27 (SCA27, an autosomal dominant disorder characterized by severe heterogeneous motor and cognitive impairments. Consistently, genetic deletion of Fgf14 in Fgf14-/- mice recapitulates salient features of the SCA27 human disease. In vitro molecular studies in cultured neurons indicate that the FGF14F145S SCA27 allele acts as a dominant negative mutant suppressing the FGF14 wild type function and resulting in inhibition of voltage-gated Na+ and Ca2+ channels. To gain insights in the cerebellar deficits in the animal model of the human disease, we applied whole-cell voltage-clamp in the acute cerebellar slice preparation to examine the properties of parallel fibers (PF to Purkinje neuron synapses in Fgf14-/- mice and wild type littermates. We found that the AMPA receptor-mediated excitatory postsynaptic currents evoked by PF stimulation (PF-EPSCs were significantly reduced in Fgf14-/- animals, while short-term plasticity, measured as paired-pulse facilitation (PPF, was enhanced. Measuring Sr2+-induced release of quanta from stimulated synapses, we found that the size of the PF-EPSCs was unchanged, ruling out a postsynaptic deficit. This phenotype was corroborated by decreased expression of VGLUT1, a specific presynaptic marker at PF-Purkinje neuron synapses. We next examined the mGluR1 receptor-induced response (mGluR1-EPSC that under normal conditions requires a gradual build-up of glutamate concentration in the synaptic cleft, and found no changes in these responses in Fgf14-/- mice. These results provide evidence of a critical role of FGF14 in maintaining presynaptic function at PF-Purkinje neuron synapses highlighting critical target mechanisms to recapitulate the complexity of the SCA27 disease.

  10. Long-term potentiation of inhibitory synaptic transmission onto cerebellar Purkinje neurons contributes to adaptation of vestibulo-ocular reflex.

    Science.gov (United States)

    Tanaka, Shinsuke; Kawaguchi, Shin-Ya; Shioi, Go; Hirano, Tomoo

    2013-10-23

    Synaptic plasticity in the cerebellum is thought to contribute to motor learning. In particular, long-term depression (LTD) at parallel fiber (PF) to Purkinje neuron (PN) excitatory synapses has attracted much attention of neuroscientists as a primary cellular mechanism for motor learning. In contrast, roles of plasticity at cerebellar inhibitory synapses in vivo remain unknown. Here, we have investigated the roles of long-lasting enhancement of transmission at GABAergic synapses on a PN that is known as rebound potentiation (RP). Previous studies demonstrated that binding of GABAA receptor with GABAA receptor-associated protein (GABARAP) is required for RP, and that a peptide that blocks this binding suppresses RP induction. To address the functional roles of RP, we generated transgenic mice that express this peptide fused to a fluorescent protein selectively in PNs using the PN-specific L7 promoter. These mice failed to show RP, although they showed no changes in the basal amplitude or frequency of miniature IPSCs. The transgenic mice also showed no abnormality in gross cerebellar morphology, LTD, or other excitatory synaptic properties, or intrinsic excitability of PNs. Next, we attempted to evaluate their motor control and learning ability by examining reflex eye movements. The basal dynamic properties of the vestibulo-ocular reflex and optokinetic response, and adaptation of the latter, were normal in the transgenic mice. In contrast, the transgenic mice showed defects in the adaptation of vestibulo-ocular reflex, a model paradigm of cerebellum-dependent motor learning. These results together suggest that RP contributes to a certain type of motor learning.

  11. Climbing fiber signaling and cerebellar gain control

    NARCIS (Netherlands)

    G. Ohtsuki (Gen); C. Piochon (Claire); C.R.W. Hansel (Christian)

    2009-01-01

    textabstractThe physiology of climbing fiber signals in cerebellar Purkinje cells has been studied since the early days of electrophysiology. Both the climbing fiber-evoked complex spike and the role of climbing fiber activity in the induction of long-term depression (LTD) at parallel fiber-Purkinje

  12. Ataxia with loss of Purkinje cells in a mouse model for Refsum disease.

    Science.gov (United States)

    Ferdinandusse, Sacha; Zomer, Anna W M; Komen, Jasper C; van den Brink, Christina E; Thanos, Melissa; Hamers, Frank P T; Wanders, Ronald J A; van der Saag, Paul T; Poll-The, Bwee Tien; Brites, Pedro

    2008-11-18

    Refsum disease is caused by a deficiency of phytanoyl-CoA hydroxylase (PHYH), the first enzyme of the peroxisomal alpha-oxidation system, resulting in the accumulation of the branched-chain fatty acid phytanic acid. The main clinical symptoms are polyneuropathy, cerebellar ataxia, and retinitis pigmentosa. To study the pathogenesis of Refsum disease, we generated and characterized a Phyh knockout mouse. We studied the pathological effects of phytanic acid accumulation in Phyh(-/-) mice fed a diet supplemented with phytol, the precursor of phytanic acid. Phytanic acid accumulation caused a reduction in body weight, hepatic steatosis, and testicular atrophy with loss of spermatogonia. Phenotype assessment using the SHIRPA protocol and subsequent automated gait analysis using the CatWalk system revealed unsteady gait with strongly reduced paw print area for both fore- and hindpaws and reduced base of support for the hindpaws. Histochemical analyses in the CNS showed astrocytosis and up-regulation of calcium-binding proteins. In addition, a loss of Purkinje cells in the cerebellum was observed. No demyelination was present in the CNS. Motor nerve conduction velocity measurements revealed a peripheral neuropathy. Our results show that, in the mouse, high phytanic acid levels cause a peripheral neuropathy and ataxia with loss of Purkinje cells. These findings provide important insights in the pathophysiology of Refsum disease.

  13. In Vivo Detection of Reduced Purkinje Cell Fibers with Diffusion MRI Tractography in Children with Autistic Spectrum Disorders

    Directory of Open Access Journals (Sweden)

    Jeong-Won eJeong

    2014-02-01

    Full Text Available Postmortem neuropathology studies report reduced number and size of Purkinje cells (PC in a majority of cerebellum specimens from persons with autism spectrum disorders (ASD. In this study using diffusion weighted MRI, we investigated whether structural changes related to decreased number and size of PC could be detected in vivo by measuring streamlines connecting the posterior-lateral region of the cerebellar cortex to the dentate nucleus using an independent component analysis with a ball and stick model (ICA+BSM. The tractography was performed in 14 typically developing children (TD and 15 children with ASD, using a cerebellar cortex seed region (crus I and II and two sorting regions, the dorsal dentate nucleus (DDN and the ventral dentate nucleus (VDN. Decreased numbers of streamlines were found in the children with ASD in the pathway connecting cerebellar cortex to right VDN (p-value = 0.015. Reduced fractional anisotropy values were observed in pathways connecting the cerebellar cortex to the right DDN (p-value=0.008, the right VDN (p-value=0.010 and left VDN (p-value=0.020 in children with ASD compared to the TD group. In an analysis of single subjects, reduced FA in the pathway connecting cerebellar cortex to the right VDN was found in 73% of the children in the ASD group using a threshold of 3 standards errors of the TD group. The detection of diffusion changes in cerebellum may provide an in vivo biomarker of Purkinje cell pathology in children with ASD.

  14. Cbln1 accumulates and colocalizes with Cbln3 and GluRδ2 at parallel fiber-Purkinje cell synapses in the mouse cerebellum

    OpenAIRE

    Miura, Eriko; Matsuda, Keiko; Morgan, James I.; Yuzaki, Michisuke; Watanabe, Masahiko

    2009-01-01

    Cbln1 (a.k.a. precerebellin) is secreted from cerebellar granule cells as homohexamer or in heteromeric complexes with Cbln3. Cbln1 plays crucial roles in regulating morphological integrity of parallel fiber (PF)-Purkinje cell (PC) synapses and synaptic plasticity; Cbln1-knockout mice display severe cerebellar phenotypes that are essentially indistinguishable from those in glutamate receptor GluRδ2-null mice and include, severe reduction in the number of PF-PC synapses and loss of long-term d...

  15. Rescue of motor coordination by Purkinje cell-targeted restoration of Kv3.3 channels in Kcnc3-null mice requires Kcnc1.

    Science.gov (United States)

    Hurlock, Edward C; Bose, Mitali; Pierce, Ganon; Joho, Rolf H

    2009-12-16

    The role of cerebellar Kv3.1 and Kv3.3 channels in motor coordination was examined with an emphasis on the deep cerebellar nuclei (DCN). Kv3 channel subunits encoded by Kcnc genes are distinguished by rapid activation and deactivation kinetics that support high-frequency, narrow action potential firing. Previously we reported that increased lateral deviation while ambulating and slips while traversing a narrow beam of ataxic Kcnc3-null mice were corrected by restoration of Kv3.3 channels specifically to Purkinje cells, whereas Kcnc3-mutant mice additionally lacking one Kcnc1 allele were partially rescued. Here, we report mice lacking all Kcnc1 and Kcnc3 alleles exhibit no such rescue. For Purkinje cell output to reach the rest of the brain it must be conveyed by neurons of the DCN or vestibular nuclei. As Kcnc1, but not Kcnc3, alleles are lost, mutant mice exhibit increasing gait ataxia accompanied by spike broadening and deceleration in DCN neurons, suggesting the facet of coordination rescued by Purkinje-cell-restricted Kv3.3 restoration in mice lacking just Kcnc3 is hypermetria, while gait ataxia emerges when additionally Kcnc1 alleles are lost. Thus, fast repolarization in Purkinje cells appears important for normal movement velocity, whereas DCN neurons are a prime candidate locus where fast repolarization is necessary for normal gait patterning.

  16. Rescue of Motor Coordination by Purkinje Cell-Targeted Restoration of Kv3.3 Channels in Kcnc3-Null Mice Requires Kcnc1

    Science.gov (United States)

    Hurlock, Edward C.; Bose, Mitali; Pierce, Ganon

    2009-01-01

    The role of cerebellar Kv3.1 and Kv3.3 channels in motor coordination was examined with an emphasis on the deep cerebellar nuclei (DCN). Kv3 channel subunits encoded by Kcnc genes are distinguished by rapid activation and deactivation kinetics that support high-frequency, narrow action potential firing. Previously we reported that increased lateral deviation while ambulating and slips while traversing a narrow beam of ataxic Kcnc3-null mice were corrected by restoration of Kv3.3 channels specifically to Purkinje cells, whereas Kcnc3-mutant mice additionally lacking one Kcnc1 allele were partially rescued. Here, we report mice lacking all Kcnc1 and Kcnc3 alleles exhibit no such rescue. For Purkinje cell output to reach the rest of the brain it must be conveyed by neurons of the DCN or vestibular nuclei. As Kcnc1, but not Kcnc3, alleles are lost, mutant mice exhibit increasing gait ataxia accompanied by spike broadening and deceleration in DCN neurons, suggesting the facet of coordination rescued by Purkinje-cell-restricted Kv3.3 restoration in mice lacking just Kcnc3 is hypermetria, while gait ataxia emerges when additionally Kcnc1 alleles are lost. Thus, fast repolarization in Purkinje cells appears important for normal movement velocity, whereas DCN neurons are a prime candidate locus where fast repolarization is necessary for normal gait patterning. PMID:20016089

  17. Bergmann glia and the recognition molecule CHL1 organize GABAergic axons and direct innervation of Purkinje cell dendrites.

    Directory of Open Access Journals (Sweden)

    Fabrice Ango

    2008-04-01

    Full Text Available The geometric and subcellular organization of axon arbors distributes and regulates electrical signaling in neurons and networks, but the underlying mechanisms have remained elusive. In rodent cerebellar cortex, stellate interneurons elaborate characteristic axon arbors that selectively innervate Purkinje cell dendrites and likely regulate dendritic integration. We used GFP BAC transgenic reporter mice to examine the cellular processes and molecular mechanisms underlying the development of stellate cell axons and their innervation pattern. We show that stellate axons are organized and guided towards Purkinje cell dendrites by an intermediate scaffold of Bergmann glial (BG fibers. The L1 family immunoglobulin protein Close Homologue of L1 (CHL1 is localized to apical BG fibers and stellate cells during the development of stellate axon arbors. In the absence of CHL1, stellate axons deviate from BG fibers and show aberrant branching and orientation. Furthermore, synapse formation between aberrant stellate axons and Purkinje dendrites is reduced and cannot be maintained, leading to progressive atrophy of axon terminals. These results establish BG fibers as a guiding scaffold and CHL1 a molecular signal in the organization of stellate axon arbors and in directing their dendritic innervation.

  18. Curcumin alters motor coordination but not total number of Purkinje cells in the cerebellum of adolescent male Wistar rats

    Institute of Scientific and Technical Information of China (English)

    Ginus Partadiredja; Sutarman; Taufik Nur Yahya; Christiana Tri Nuryana; Rina Susilowati

    2013-01-01

    OBJECTIVE:The present study aimed at investigating the effects of curcumin on the motor coordination and the estimate of the total number of cerebellar Purkinje cells of adolescent Wistar rats exposed to ethanol.METHODS:The total of 21 male Wistar rats aged 37 d old were divided into three groups,namely ethanol,ethanol-curcumin,and control groups.The ethanol group received 1.5 g/kg ethanol injected intraperitoneally and water given per oral; the ethanol-curcumin group received 1.5 g/kg ethanol injected intraperitoneally and curcumin extract given per oral; the control group received saline injection and oral water.The treatment was carried out daily for one month,after which the motor coordination performance of the rats was examined using revolving drum apparatus at test days 1,8,and 15.The rats were finally sacrificed and the cerebellum of the rats was further processed for stereological analysis.The estimate of the total number of Purkinje cells was calculated using physical fractionator method.RESULTS:The ethanol-curcumin group performed better than both ethanol and control groups in the motor coordination ability at day 8 of testing (P< 0.01).No Purkinje cell loss was observed as a result of one month intraperitoneal injection of ethanol.CONCLUSION:Curcumin may exert beneficial effects on the motor coordination of adolescent rats exposed to ethanol via undetermined hormetic mechanisms.

  19. Comparative morphology of dendritic arbors in populations of Purkinje cells in mouse sulcus and apex.

    Science.gov (United States)

    Nedelescu, Hermina; Abdelhack, Mohamed

    2013-01-01

    Foliation divides the mammalian cerebellum into structurally distinct subdivisions, including the concave sulcus and the convex apex. Purkinje cell (PC) dendritic morphology varies between subdivisions and changes significantly ontogenetically. Since dendritic morphology both enables and limits sensory-motor circuit function, it is important to understand how neuronal architectures differ between brain regions. This study employed quantitative confocal microcopy to reconstruct dendritic arbors of cerebellar PCs expressing green fluorescent protein and compared arbor morphology between PCs of sulcus and apex in young and old mice. Arbors were digitized from high z-resolution (0.25 µm) image stacks using an adaptation of Neurolucida's (MBF Bioscience) continuous contour tracing tool, designed for drawing neuronal somata. Reconstructed morphologies reveal that dendritic arbors of sulcus and apex exhibit profound differences. In sulcus, 72% of the young PC population possesses two primary dendrites, whereas in apex, only 28% do. Spatial constraints in the young sulcus cause significantly more dendritic arbor overlap than in young apex, a distinction that disappears in adulthood. However, adult sulcus PC arbors develop a greater number of branch crossings. These results suggest developmental neuronal plasticity that enables cerebellar PCs to attain correct functional adult architecture under different spatial constraints.

  20. SELECTIVE EFFECTS OF DATURA STRAMONIUM ON THE GRANULAR PARALLEL FIBRES AND PURKINJE CELLS OF THE CEREBELLUM IN WISTAR RATS

    Directory of Open Access Journals (Sweden)

    Peter E. Ekanem

    2015-12-01

    Full Text Available Introduction: Datura stramonium (DS is a tropical ubiquitous shrub which is often used to increase intoxication in some beverages and is also freely used as a hallucinogen. It is a depressant of the central nervous system, yet commonly smoked in like manner tobacco. The present study investigated changes induced by intoxication with DS on the purkinje cells and parallel fibres of the cerebellum in Wistar rats to further elucidate the effects of this drug on cerebellar structure. Materials and Methods: The study was conducted on both male and female Wistar rats (200-250 g. They were placed into three batches and four groups were derived from each batch, with eight animals per group. Ethanolic dried seed extract of DS was diluted in normal saline and administered intraperitoneally (I.P. at a dose of 750mg/kg and given to the treatment groups: once in batch 1, twice in batch 2, twelve hourly and thrice in batch 3, eight hourly per day respectively for 4 weeks, while the control groups received an equivalent of normal saline. The rats were euthanized and sections of the cerebellum were histologically processed in all groups. Silver impregnation stain for degenerating axons and neurons was used to elucidate the actions of DS on purkinje cells and the parallel fibres of the cerebellum. Results: The result of IP administration of DS extract (750 mg/kg given three times daily to the treated rats showed significant histological changes, which included atrophy of the parallel fibres but no significant changes in the purkinje cells of the cerebellum. Conclusions: Intoxication of DS seed as a result of excessive ingestion may have a selective degenerative effect on the parallel fibres of the granule cells of the cerebellum while the purkinje cells are spared; the implication being motor dysfunction.

  1. Releasing dentate nucleus cells from Purkinje cell inhibition generates output from the cerebrocerebellum.

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    Takahiro Ishikawa

    Full Text Available The cerebellum generates its vast amount of output to the cerebral cortex through the dentate nucleus (DN that is essential for precise limb movements in primates. Nuclear cells in DN generate burst activity prior to limb movement, and inactivation of DN results in cerebellar ataxia. The question is how DN cells become active under intensive inhibitory drive from Purkinje cells (PCs. There are two excitatory inputs to DN, mossy fiber and climbing fiber collaterals, but neither of them appears to have sufficient strength for generation of burst activity in DN. Therefore, we can assume two possible mechanisms: post-inhibitory rebound excitation and disinhibition. If rebound excitation works, phasic excitation of PCs and a concomitant inhibition of DN cells should precede the excitation of DN cells. On the other hand, if disinhibition plays a primary role, phasic suppression of PCs and activation of DN cells should be observed at the same timing. To examine these two hypotheses, we compared the activity patterns of PCs in the cerebrocerebellum and DN cells during step-tracking wrist movements in three Japanese monkeys. As a result, we found that the majority of wrist-movement-related PCs were suppressed prior to movement onset and the majority of wrist-movement-related DN cells showed concurrent burst activity without prior suppression. In a minority of PCs and DN cells, movement-related increases and decreases in activity, respectively, developed later. These activity patterns suggest that the initial burst activity in DN cells is generated by reduced inhibition from PCs, i.e., by disinhibition. Our results indicate that suppression of PCs, which has been considered secondary to facilitation, plays the primary role in generating outputs from DN. Our findings provide a new perspective on the mechanisms used by PCs to influence limb motor control and on the plastic changes that underlie motor learning in the cerebrocerebellum.

  2. Mechanisms of ethanol-induced death of cerebellar granule cells.

    Science.gov (United States)

    Luo, Jia

    2012-03-01

    Maternal ethanol exposure during pregnancy may cause fetal alcohol spectrum disorders (FASD). FASD is the leading cause of mental retardation. The most deleterious effect of fetal alcohol exposure is inducing neuroapoptosis in the developing brain. Ethanol-induced loss of neurons in the central nervous system underlies many of the behavioral deficits observed in FASD. The cerebellum is one of the brain areas that are most susceptible to ethanol during development. Ethanol exposure causes a loss of both cerebellar Purkinje cells and granule cells. This review focuses on the toxic effect of ethanol on cerebellar granule cells (CGC) and the underlying mechanisms. Both in vitro and in vivo studies indicate that ethanol induces apoptotic death of CGC. The vulnerability of CGC to ethanol-induced death diminishes over time as neurons mature. Several mechanisms for ethanol-induced apoptosis of CGC have been suggested. These include inhibition of N-methyl-D-aspartate receptors, interference with signaling by neurotrophic factors, induction of oxidative stress, modulation of retinoid acid signaling, disturbance of potassium channel currents, thiamine deficiency, and disruption of translational regulation. Cultures of CGC provide an excellent system to investigate cellular/molecular mechanisms of ethanol-induced neurodegeneration and to evaluate interventional strategies. This review will also discuss the approaches leading to neuroprotection against ethanol-induced neuroapoptosis.

  3. STD-dependent and independent encoding of input irregularity as spike rate in a computational model of a cerebellar nucleus neuron

    NARCIS (Netherlands)

    J. Luthman (Johannes); F.E. Hoebeek (Freek); R. Maex (Reinoud); N. Davey (Neil); R. Adams (Rod); C.I. de Zeeuw (Chris); V. Steuber (Volker)

    2011-01-01

    textabstractNeurons in the cerebellar nuclei (CN) receive inhibitory inputs from Purkinje cells in the cerebellar cortex and provide the major output from the cerebellum, but their computational function is not well understood. It has recently been shown that the spike activity of Purkinje cells is

  4. Subcellular structural plasticity caused by the absence of the fast Ca2+ buffer calbindin D-28k in recurrent collaterals of cerebellar Purkinje neurons

    Directory of Open Access Journals (Sweden)

    David eOrduz

    2014-11-01

    Full Text Available Purkinje cells (PC control spike timing of neighboring PC by their recurrent axon collaterals. These synapses underlie fast cerebellar oscillations and are characterized by a strong facilitation within a time window of <20 ms during paired-pulse protocols. PC express high levels of the fast Ca2+ buffer protein calbindin D-28k (CB. As expected from the absence of a fast Ca2+ buffer, presynaptic action potential-evoked [Ca2+]i transients were previously shown to be bigger in PC boutons of young (second postnatal week CB-/- mice, yet IPSC mean amplitudes remained unaltered in connected CB-/- PC. Since PC spine morphology is altered in adult CB-/- mice (longer necks, larger spine head volume, we summoned that morphological compensation/adaptation mechanisms might also be induced in CB-/- PC axon collaterals including boutons. In these mice, biocytin-filled PC reconstructions revealed that the number of axonal varicosities per PC axon collateral was augmented, mostly confined to the granule cell layer. Additionally, the volume of individual boutons was increased, evidenced from z-stacks of confocal images. EM analysis of PC-PC synapses revealed an enhancement in active zone (AZ length by approximately 23%, paralleled by a higher number of docked vesicles per AZ in CB-/- boutons. Moreover, synaptic cleft width was larger in CB-/- (23.8 ± 0.43 nm compared to wild type (21.17 ± 0.39 nm synapses. We propose that the morphological changes, i.e. the larger bouton volume, the enhanced AZ length and the higher number of docked vesicles, in combination with the increase in synaptic cleft width likely modifies the GABA release properties at this synapse in CB-/- mice. We view these changes as adaptation/homeostatic mechanisms to likely maintain (preserve characteristics of synaptic transmission in the absence of the fast Ca2+ buffer CB. Our study provides further evidence on the functioning of the Ca2+ homeostasome.

  5. Synchrony and neural coding in cerebellar circuits

    Directory of Open Access Journals (Sweden)

    Abigail L Person

    2012-12-01

    Full Text Available The cerebellum regulates complex movements and is also implicated in cognitive tasks, and cerebellar dysfunction is consequently associated not only with movement disorders, but also with conditions like autism and dyslexia. How information is encoded by specific cerebellar firing patterns remains debated, however. A central question is how the cerebellar cortex transmits its integrated output to the cerebellar nuclei via GABAergic synapses from Purkinje neurons. Possible answers come from accumulating evidence that subsets of Purkinje cells synchronize their firing during behaviors that require the cerebellum. Consistent with models predicting that coherent activity of inhibitory networks has the capacity to dictate firing patterns of target neurons, recent experimental work supports the idea that inhibitory synchrony may regulate the response of cerebellar nuclear cells to Purkinje inputs, owing to the interplay between unusually fast inhibitory synaptic responses and high rates of intrinsic activity. Data from multiple laboratories lead to a working hypothesis that synchronous inhibitory input from Purkinje cells can set the timing and rate of action potentials produced by cerebellar nuclear cells, thereby relaying information out of the cerebellum. If so, then changing spatiotemporal patterns of Purkinje activity would allow different subsets of inhibitory neurons to control cerebellar output at different times. Here we explore the evidence for and against the idea that a synchrony code defines, at least in part, the input-output function between the cerebellar cortex and nuclei. We consider the literature on the existence of simple spike synchrony, convergence of Purkinje neurons onto nuclear neurons, and intrinsic properties of nuclear neurons that contribute to responses to inhibition. Finally, we discuss factors that may disrupt or modulate a synchrony code and describe the potential contributions of inhibitory synchrony to other motor

  6. Purkinje-cell-restricted restoration of Kv3.3 function restores complex spikes and rescues motor coordination in Kcnc3 mutants.

    Science.gov (United States)

    Hurlock, Edward C; McMahon, Anne; Joho, Rolf H

    2008-04-30

    The fast-activating/deactivating voltage-gated potassium channel Kv3.3 (Kcnc3) is expressed in various neuronal cell types involved in motor function, including cerebellar Purkinje cells. Spinocerebellar ataxia type 13 (SCA13) patients carrying dominant-negative mutations in Kcnc3 and Kcnc3-null mutant mice both display motor incoordination, suggested in mice by increased lateral deviation while ambulating and slips on a narrow beam. Motor skill learning, however, is spared. Mice lacking Kcnc3 also exhibit muscle twitches. In addition to broadened spikes, recordings of Kcnc3-null Purkinje cells revealed fewer spikelets in complex spikes and a lower intraburst frequency. Targeted reexpression of Kv3.3 channels exclusively in Purkinje cells in Kcnc3-null mice as well as in mice also heterozygous for Kv3.1 sufficed to restore simple spike brevity along with normal complex spikes and to rescue specifically coordination. Therefore, spike parameters requiring Kv3.3 function in Purkinje cells are involved in the ataxic null phenotype and motor coordination, but not motor learning.

  7. Postnatal dendritic morphogenesis of cerebellar basket and stellate cells in vitro.

    Science.gov (United States)

    Spatkowski, Gabriele; Schilling, Karl

    2003-05-01

    Inhibitory interneurons in the molecular layer of the cerebellar cortex play an essential role in cerebellar physiology by providing feed-forward inhibition to efferent Purkinje cells. Morphologic characteristics have been utilized to classify these cells as either basket cells or stellate cells. Conflicting evidence exists as to whether these cells are of distinct lineage and develop by employing discrete genetic programs, or whether their characteristic morphologic differences result from external cues that they encounter only after they have settled in their final territory in the molecular layer. We used primary dissociated cerebellar cultures established from early postnatal mice to study dendritogenesis of basket/stellate cells, identified by immunostaining for parvalbumin, under experimentally controlled conditions. We find that the radial axonal orientation of stem dendrites is non-random, suggesting a cell-intrinsic component defining this morphologic trait. In contrast, the expanse and complexity of basket/stellate cell dendrites is modulated by the granule cell derived neurotrophin, BDNF. BDNF-induced morphogenetic effects decline with ongoing development. Overall, our data do not provide evidence for a distinct lineage or genetic makeup of cerebellar molecular layer inhibitory interneurons.

  8. The Analysis of Purkinje Cell Dendritic Morphology in Organotypic Slice Cultures

    OpenAIRE

    Kapfhammer, Josef P.; Gugger, Olivia S.

    2012-01-01

    Purkinje cells are an attractive model system for studying dendritic development, because they have an impressive dendritic tree which is strictly oriented in the sagittal plane and develops mostly in the postnatal period in small rodents 3. Furthermore, several antibodies are available which selectively and intensively label Purkinje cells including all processes, with anti-Calbindin D28K being the most widely used. For viewing of dendrites in living cells, mice expressing EGFP selectively i...

  9. The sorting receptor Rer1 controls Purkinje cell function via voltage gated sodium channels

    Science.gov (United States)

    Valkova, Christina; Liebmann, Lutz; Krämer, Andreas; Hübner, Christian A.; Kaether, Christoph

    2017-01-01

    Rer1 is a sorting receptor in the early secretory pathway that controls the assembly and the cell surface transport of selected multimeric membrane protein complexes. Mice with a Purkinje cell (PC) specific deletion of Rer1 showed normal polarization and differentiation of PCs and normal development of the cerebellum. However, PC-specific loss of Rer1 led to age-dependent motor deficits in beam walk, ladder climbing and gait. Analysis of brain sections revealed a specific degeneration of PCs in the anterior cerebellar lobe in old animals. Electrophysiological recordings demonstrated severe deficits in spontaneous action potential generation. Measurements of resurgent currents indicated decreased surface densities of voltage-gated sodium channels (Nav), but not changes in individual channels. Analysis of mice with a whole brain Rer1-deletion demonstrated a strong down-regulation of Nav1.6 and 1.1 in the absence of Rer1, whereas protein levels of the related Cav2.1 and of Kv3.3 and 7.2 channels were not affected. The data suggest that Rer1 controls the assembly and transport of Nav1.1 and 1.6, the principal sodium channels responsible for recurrent firing, in PCs. PMID:28117367

  10. The volume of Purkinje cells decreases in the cerebellum of acrylamide-intoxicated rats, but no cells are lost

    DEFF Research Database (Denmark)

    Larsen, Jytte Overgaard; Tandrup, T; Braendgaard, H

    1994-01-01

    estimated using the Cavalieri principle. The mean weight of the cerebellum of the intoxicated rats was 7% lower than that of the control rats (2P = 0.001). The numbers of the Purkinje cells and granule cells were the same in both groups, but the mean volume of the perikarya of the Purkinje cells...

  11. GABA-A Inhibition Shapes the Spatial and Temporal Response Properties of Purkinje Cells in the Macaque Cerebellum

    Directory of Open Access Journals (Sweden)

    Pablo M. Blazquez

    2015-05-01

    Full Text Available Data from in vitro and anesthetized preparations indicate that inhibition plays a major role in cerebellar cortex function. We investigated the role of GABA-A inhibition in the macaque cerebellar ventral-paraflocculus while animals performed oculomotor behaviors that are known to engage the circuit. We recorded Purkinje cell responses to these behaviors with and without application of gabazine, a GABA-A receptor antagonist, near the recorded neuron. Gabazine increased the neuronal responsiveness to saccades in all directions and the neuronal gain to VOR cancellation and pursuit, most significantly the eye and head velocity sensitivity. L-glutamate application indicated that these changes were not the consequence of increases in baseline firing rate. Importantly, gabazine did not affect behavior or efference copy, suggesting that only local computations were disrupted. Our data, collected while the cerebellum performs behaviorally relevant computations, indicate that inhibition is a potent regulatory mechanism for the control of input-output gain and spatial tuning in the cerebellar cortex.

  12. Evolving Models of Pavlovian Conditioning : Cerebellar Cortical Dynamics in Awake Behaving Mice

    NARCIS (Netherlands)

    Ten Brinke, Michiel M; Boele, Henk-Jan; Spanke, Jochen K; Potters, Jan-Willem; Kornysheva, Katja; Wulff, Peer; IJpelaar, Anna C H G; Koekkoek, Sebastiaan K E; De Zeeuw, Chris I

    2015-01-01

    Three decades of electrophysiological research on cerebellar cortical activity underlying Pavlovian conditioning have expanded our understanding of motor learning in the brain. Purkinje cell simple spike suppression is considered to be crucial in the expression of conditional blink responses (CRs).

  13. Multiple types of cerebellar target neurons and their circuitry in the vestibulo-ocular reflex.

    Science.gov (United States)

    Shin, Minyoung; Moghadam, Setareh H; Sekirnjak, Chris; Bagnall, Martha W; Kolkman, Kristine E; Jacobs, Richard; Faulstich, Michael; du Lac, Sascha

    2011-07-27

    The cerebellum influences behavior and cognition exclusively via Purkinje cell synapses onto neurons in the deep cerebellar and vestibular nuclei. In contrast with the rich information available about the organization of the cerebellar cortex and its synaptic inputs, relatively little is known about microcircuitry postsynaptic to Purkinje cells. Here we examined the cell types and microcircuits through which Purkinje cells influence an oculomotor behavior controlled by the cerebellum, the horizontal vestibulo-ocular reflex, which involves only two eye muscles. Using a combination of anatomical tracing and electrophysiological recordings in transgenic mouse lines, we identified several classes of neurons in the medial vestibular nucleus that receive Purkinje cell synapses from the cerebellar flocculus. Glycinergic and glutamatergic flocculus target neurons (FTNs) with somata densely surrounded by Purkinje cell terminals projected axons to the ipsilateral abducens and oculomotor nuclei, respectively. Of three additional types of FTNs that were sparsely innervated by Purkinje cells, glutamatergic and glycinergic neurons projected to the contralateral and ipsilateral abducens, respectively, and GABAergic neurons projected to contralateral vestibular nuclei. Densely innervated FTNs had high spontaneous firing rates and pronounced postinhibitory rebound firing, and were physiologically homogeneous, whereas the intrinsic excitability of sparsely innervated FTNs varied widely. Heterogeneity in the molecular expression, physiological properties, and postsynaptic targets of FTNs implies that Purkinje cell activity influences the neural control of eye movements in several distinct ways. These results indicate that the cerebellum regulates a simple reflex behavior via at least five different cell types that are postsynaptic to Purkinje cells.

  14. Transplantation of cerebellar neural stem cells improves motor coordination and neuropathology in Machado-Joseph disease mice.

    Science.gov (United States)

    Mendonça, Liliana S; Nóbrega, Clévio; Hirai, Hirokazu; Kaspar, Brian K; Pereira de Almeida, Luís

    2015-02-01

    Machado-Joseph disease is a neurodegenerative disease without effective treatment. Patients with Machado-Joseph disease exhibit significant motor impairments such as gait ataxia, associated with multiple neuropathological changes including mutant ATXN3 inclusions, marked neuronal loss and atrophy of the cerebellum. Thus, an effective treatment of symptomatic patients with Machado-Joseph disease may require cell replacement, which we investigated in this study. For this purpose, we injected cerebellar neural stem cells into the cerebellum of adult Machado-Joseph disease transgenic mice and assessed the effect on the neuropathology, neuroinflammation mediators and neurotrophic factor levels and motor coordination. We found that upon transplantation into the cerebellum of adult Machado-Joseph disease mice, cerebellar neural stem cells differentiate into neurons, astrocytes and oligodendrocytes. Importantly, cerebellar neural stem cell transplantation mediated a significant and robust alleviation of the motor behaviour impairments, which correlated with preservation from Machado-Joseph disease-associated neuropathology, namely reduction of Purkinje cell loss, reduction of cellular layer shrinkage and mutant ATXN3 aggregates. Additionally, a significant reduction of neuroinflammation and an increase of neurotrophic factors levels was observed, indicating that transplantation of cerebellar neural stem cells also triggers important neuroprotective effects. Thus, cerebellar neural stem cells have the potential to be used as a cell replacement and neuroprotective approach for Machado-Joseph disease therapy.

  15. Immuno-histochemistry and three-dimensional architecture of the intermediate filaments in Purkinje cells in mammalian hearts.

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    Yoshimura, Akira; Yamaguchi, Takeshi; Kawazato, Hiroaki; Takahashi, Naohiko; Shimada, Tatsuo

    2014-12-01

    In mammalian hearts, Purkinje cells varied greatly in morphological appearance in different species, and were divided into three groups. Bovine Purkinje cells corresponding to group I were a large size, and had a few myofibrils and abundant intermediate filaments throughout the cytoplasm. The aim of the present study was to clarify the more detailed distribution and three-dimensional architecture of intermediate filaments in Purkinje cells. The hearts in various mammals including humans were investigated by both immuno-histochemistry and scanning electron microscopy (SEM).Immuno-histochemical studies demonstrated that sheep Purkinje cells in group I had a great number of intermediate filaments of 10 nm positive for desmin antibody. Purkinje cells in group II (humans, monkeys and dogs) and group III (mice) were somewhat larger or smaller in size than myocardial cells, but also showed a strong positive reaction for desmin antibody. The saponin or NaOH treatment of cardiac tissues in sheep and humans enabled us to view intermediate filaments by SEM three-dimensionally. Intermediate filaments in sheep Purkinje cells formed a considerably delicate network, and were distributed throughout the cytoplasm. In contrast, those in human Purkinje cells were lower in density, and were present around the nucleus and between myofibrils. It was concluded that a delicate network of intermediate filaments in Purkinje cells of mammalian hearts acted as the cytoskeleton to maintain intercellular stability.

  16. Motor dysfunction and altered synaptic transmission at the parallel fiber-Purkinje cell synapse in mice lacking potassium channels Kv3.1 and Kv3.3.

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    Matsukawa, Hiroshi; Wolf, Alexander M; Matsushita, Shinichi; Joho, Rolf H; Knöpfel, Thomas

    2003-08-20

    Micelacking both Kv3.1 and both Kv3.3 K+ channel alleles display severe motor deficits such as tremor, myoclonus, and ataxic gait. Micelacking one to three alleles at the Kv3.1 and Kv3.3 loci exhibit in an allele dose-dependent manner a modest degree of ataxia. Cerebellar granule cells coexpress Kv3.1 and Kv3.3 K+ channels and are therefore candidate neurons that might be involved in these behavioral deficits. Hence, we investigated the synaptic mechanisms of transmission in the parallel fiber-Purkinje cell system. Action potentials of parallel fibers were broader in mice lacking both Kv3.1 and both Kv3.3 alleles and in mice lacking both Kv3.1 and a single Kv3.3 allele compared with those of wild-type mice. The transmission of high-frequency trains of action potentials was only impaired at 200 Hz but not at 100 Hz in mice lacking both Kv3.1 and Kv3.3 genes. However, paired-pulse facilitation (PPF) at parallel fiber-Purkinje cell synapses was dramatically reduced in a gene dose-dependent manner in mice lacking Kv3.1 or Kv3.3 alleles. Normal PPF could be restored by reducing the extracellular Ca2+ concentration indicating that increased activity-dependent presynaptic Ca2+ influx, at least in part caused the altered PPF in mutant mice. Induction of metabotropic glutamate receptor-mediated EPSCs was facilitated, whereas longterm depression was not impaired but rather facilitated in Kv3.1/Kv3.3 double-knockout mice. These results demonstrate the importance of Kv3 potassium channels in regulating the dynamics of synaptic transmission at the parallel fiber-Purkinje cell synapse and suggest a correlation between short-term plasticity at the parallel fiber-Purkinje cell synapse and motor performance.

  17. Molecular markers of neuronal progenitors in the embryonic cerebellar anlage.

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    Morales, Daniver; Hatten, Mary E

    2006-11-22

    The cerebellum, like the cerebrum, includes a nuclear structure and an overlying cortical structure. Experiments in the past decade have expanded knowledge beyond the traditional function of the cerebellum to include critical roles in motor learning and memory and sensory discrimination. The initial steps in cerebellar development depend on inductive signaling involving FGF and Wnt proteins produced at the mesencephalic/metencephalic boundary. To address the issue of how individual cerebellar cell fates within the cerebellar territory are specified, we examined the expression of transcription factors, including mammalian homologues of LIM homeodomain-containing proteins, basic helix-loop-helix proteins, and three amino acid loop-containing proteins. The results of these studies show that combinatorial codes of transcription factors define precursors of the cerebellar nuclei, and both Purkinje cells and granule neurons of the cerebellar cortex. Examination of gene expression patterns in several hundred lines of Egfp-BAC (bacterial artificial chromosome) transgenic mice in the GENSAT Project revealed numerous genes with restricted expression in cerebellar progenitor populations, including genes specific for cerebellar nuclear precursors and Purkinje cell precursors. In addition, we identified patterns of gene expression that link granule and Purkinje cells to their precerebellar nuclei. These results identify molecular pathways that offer new insights on the development of the nuclear and cortical structures of the cerebellum, as well as components of the cerebellar circuitry.

  18. Quantitative neuroanatomy of all Purkinje cells with light sheet microscopy and high-throughput image analysis

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    Ludovico eSilvestri

    2015-05-01

    Full Text Available Characterizing the cytoarchitecture of mammalian central nervous system on a brain-wide scale is becoming a compelling need in neuroscience. For example, realistic modeling of brain activity requires the definition of quantitative features of large neuronal populations in the whole brain. Quantitative anatomical maps will also be crucial to classify the cytoarchtitectonic abnormalities associated with neuronal pathologies in a high reproducible and reliable manner. In this paper, we apply recent advances in optical microscopy and image analysis to characterize the spatial distribution of Purkinje cells across the whole cerebellum. Light sheet microscopy was used to image with micron-scale resolution a fixed and cleared cerebellum of an L7-GFP transgenic mouse, in which all Purkinje cells are fluorescently labeled. A fast and scalable algorithm for fully automated cell identification was applied on the image to extract the position of all the fluorescent Purkinje cells. This vectorized representation of the cell population allows a thorough characterization of the complex three-dimensional distribution of the neurons, highlighting the presence of gaps inside the lamellar organization of Purkinje cells, whose density is believed to play a significant role in autism spectrum disorders. Furthermore, clustering analysis of the localized somata permits dividing the whole cerebellum in groups of Purkinje cells with high spatial correlation, suggesting new possibilities of anatomical partition. The quantitative approach presented here can be extended to study the distribution of different types of cell in many brain regions and across the whole encephalon, providing a robust base for building realistic computational models of the brain, and for unbiased morphological tissue screening in presence of pathologies and/or drug treatments.

  19. Vulnerability of Purkinje Cells Generated from Spinocerebellar Ataxia Type 6 Patient-Derived iPSCs

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    Yoshihito Ishida

    2016-11-01

    Full Text Available Spinocerebellar ataxia type 6 (SCA6 is a dominantly inherited neurodegenerative disease characterized by loss of Purkinje cells in the cerebellum. SCA6 is caused by CAG trinucleotide repeat expansion in CACNA1A, which encodes Cav2.1, α1A subunit of P/Q-type calcium channel. However, the pathogenic mechanism and effective therapeutic treatments are still unknown. Here, we have succeeded in generating differentiated Purkinje cells that carry patient genes by combining disease-specific iPSCs and self-organizing culture technologies. Patient-derived Purkinje cells exhibit increased levels of full-length Cav2.1 protein but decreased levels of its C-terminal fragment and downregulation of the transcriptional targets TAF1 and BTG1. We further demonstrate that SCA6 Purkinje cells exhibit thyroid hormone depletion-dependent degeneration, which can be suppressed by two compounds, thyroid releasing hormone and Riluzole. Thus, we have constructed an in vitro disease model recapitulating both ontogenesis and pathogenesis. This model may be useful for pathogenic investigation and drug screening.

  20. Embryonic origins of ZebrinII parasagittal stripes and establishment of topographic Purkinje cell projections.

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    Sillitoe, R V; Gopal, N; Joyner, A L

    2009-09-01

    The establishment of neural circuits involves both the precise positioning of cells within brain regions and projection of axons to specific target cells. In the cerebellum (Cb), the medial-lateral (M-L) and anterior-posterior (A-P) position of each Purkinje cell (PC) and the topography of its axon can be defined with respect to two coordinate systems within the Cb; one based on the pattern of lobules and the other on PC gene expression in parasagittal clusters in the embryo (e.g. Pcp2) and stripes in the adult (e.g. ZebrinII). The relationship between the embryonic clusters of molecularly defined PCs and particular adult PC stripes is not clear. Using a mouse genetic inducible fate mapping (GIFM) approach and a Pcp2-CreER-IRES-hAP transgene, we marked three bilateral clusters of PC clusters with myristolated green fluorescent protein (mGfp) on approximately embryonic day (E) 15 and followed their fate into adulthood. We found that these three clusters contributed specifically to ZebrinII-expressing PCs, including nine of the adult stripes. This result suggests that embryonic PCs maintain a particular molecular identity, and that each embryonic cluster can contribute PCs to more than one adult M-L stripe. Each PC projects a primary axon to one of the deep cerebellar nuclei (DCN) or the vestibular nuclei in the brainstem in an organized fashion that relates to the position of the PCs along the M-L axis. We characterized when PC axons from the three M-L clusters acquire topographic projections. Using a combination of GIFM to mark the PC clusters with mGfp and staining for human placental alkaline phosphatase (hAP) in Pcp2-CreER-IRES-hAP transgenic embryos we found that axons from each embryonic PC cluster intermingled with neurons within particular DCN or projected out of the Cb toward the vestibular nuclei by E14.5. These studies show that PC molecular patterning, efferent circuitry, and DCN nucleogenesis occur simultaneously, suggesting a link between these

  1. Signals and Circuits in the Purkinje Neuron

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    Ze'ev R Abrams

    2011-09-01

    Full Text Available Purkinje neurons in the cerebellum have over 100,000 inputs organized in an orthogonal geometry, and a single output channel. As the sole output of the cerebellar cortex layer, their complex firing pattern has been associated with motor control and learning. As such they have been extensively modeled and measured using tools ranging from electrophysiology and neuroanatomy, to dynamic systems and artificial intelligence methods. However, there is an alternative approach to analyze and describe the neuronal output of these cells using concepts from Electrical Engineering, particularly signal processing and digital/analog circuits. By viewing the Purkinje neuron as an unknown circuit to be reverse-engineered, we can use the tools that provide the foundations of today’s integrated circuits and communication systems to analyze the Purkinje system at the circuit level. We use Fourier transforms to analyze and isolate the inherent frequency modes in the Purkinje neuron and define 3 unique frequency ranges associated with the cells’ output. Comparing the Purkinje neuron to a signal generator that can be externally modulated adds an entire level of complexity to the functional role of these neurons both in terms of data analysis and information processing, relying on Fourier analysis methods in place of statistical ones. We also re-describe some of the recent literature in the field, using the nomenclature of signal processing. Furthermore, by comparing the experimental data of the past decade with basic electronic circuitry, we can resolve the outstanding controversy in the field, by recognizing that the Purkinje neuron can act as a multivibrator circuit.

  2. Identification of MMP-2 as a novel enhancer of cerebellar granule cell proliferation.

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    Verslegers, Mieke; Van Hove, Inge; Buyens, Tom; Dekeyster, Eline; Knevels, Ellen; Moons, Lieve

    2013-11-01

    During the first postnatal days in the mouse, granule cells (GCs) undergo massive proliferation, which then gradually decreases. Matrix metalloproteinase-2 (MMP-2), a Zn(2+)-dependent proteolytic enzyme, is involved in a wide variety of pathological and physiological pathways. Evidence for a role of this proteinase in cell proliferation is emerging, reporting its involvement in pathological proliferation, as well as during neurogenesis and developmental proliferation of non-CNS tissues. In this study, MMP-2 protein expression was observed within the early postnatal cerebellar cortex, predominantly in Purkinje cells and within the GC proliferative zone, i.e. the superficial external granular layer (EGL). Consistently, the spatiotemporal MMP-2 mRNA and protein profiles highly correlated with the peak of GC precursor (GCP) proliferation and detailed morphometric analyses of MMP-2 deficient cerebella revealed a thinner EGL due to a decreased GCP proliferation. BrdU cumulative experiments, performed to measure the length of different cell cycle phases, further disclosed a transiently prolonged S-phase in MMP-2 deficient GCPs during early cerebellar development. In consequence, MMP-2 deficient animals displayed a transient delay in GC migration towards the IGL. In conclusion, our findings provide important evidence for a role for MMP-2 in neuronal proliferation and cell cycle kinetics in the developing CNS.

  3. An integrator circuit in cerebellar cortex.

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    Maex, Reinoud; Steuber, Volker

    2013-09-01

    The brain builds dynamic models of the body and the outside world to predict the consequences of actions and stimuli. A well-known example is the oculomotor integrator, which anticipates the position-dependent elasticity forces acting on the eye ball by mathematically integrating over time oculomotor velocity commands. Many models of neural integration have been proposed, based on feedback excitation, lateral inhibition or intrinsic neuronal nonlinearities. We report here that a computational model of the cerebellar cortex, a structure thought to implement dynamic models, reveals a hitherto unrecognized integrator circuit. In this model, comprising Purkinje cells, molecular layer interneurons and parallel fibres, Purkinje cells were able to generate responses lasting more than 10 s, to which both neuronal and network mechanisms contributed. Activation of the somatic fast sodium current by subthreshold voltage fluctuations was able to maintain pulse-evoked graded persistent activity, whereas lateral inhibition among Purkinje cells via recurrent axon collaterals further prolonged the responses to step and sine wave stimulation. The responses of Purkinje cells decayed with a time-constant whose value depended on their baseline spike rate, with integration vanishing at low ( 30 per s). The model predicts that the apparently fast circuit of the cerebellar cortex may control the timing of slow processes without having to rely on sensory feedback. Thus, the cerebellar cortex may contain an adaptive temporal integrator, with the sensitivity of integration to the baseline spike rate offering a potential mechanism of plasticity of the response time-constant.

  4. Regional Regulation of Purkinje Cell Dendritic Spines by Integrins and Eph/Ephrins.

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    Heintz, Tristan G; Eva, Richard; Fawcett, James W

    2016-01-01

    Climbing fibres and parallel fibres compete for dendritic space on Purkinje cells in the cerebellum. Normally, climbing fibres populate the proximal dendrites, where they suppress the multiple small spines typical of parallel fibres, leading to their replacement by the few large spines that contact climbing fibres. Previous work has shown that ephrins acting via EphA4 are a signal for this change in spine type and density. We have used an in vitro culture model in which to investigate the ephrin effect on Purkinje cell dendritic spines and the role of integrins in these changes. We found that integrins α3, α5 and β4 are present in many of the dendritic spines of cultured Purkinje cells. pFAK, the main downstream signalling molecule from integrins, has a similar distribution, although the intenstity of pFAK staining and the percentage of pFAK+ spines was consistently higher in the proximal dendrites. Activating integrins with Mg2+ led to an increase in the intensity of pFAK staining and an increase in the proportion of pFAK+ spines in both the proximal and distal dendrites, but no change in spine length, density or morphology. Blocking integrin binding with an RGD-containing peptide led to a reduction in spine length, with more stubby spines on both proximal and distal dendrites. Treatment of the cultures with ephrinA3-Fc chimera suppressed dendritic spines specifically on the proximal dendrites and there was also a decrease of pFAK in spines on this domain. This effect was blocked by simultaneous activation of integrins with Mn2+. We conclude that Eph/ephrin signaling regulates proximal dendritic spines in Purkinje cells by inactivating integrin downstream signalling.

  5. Kv3.3b expression defines the shape of the complex spike in the Purkinje cell.

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    Veys, Ken; Snyders, Dirk; De Schutter, Erik

    2013-01-01

    The complex spike (CS) in cerebellar Purkinje Cells (PC) is not an all-or-nothing phenomena as originally proposed, but shows variability depending on the spiking behavior of the Inferior Olive and intrinsic variability in the number and shape of spikelets. The potassium channel Kv3.3b, which has been proposed to undergo developmental changes during the postnatal PC maturation, has been shown to be crucial for the repolarization of the spikelets in the CS. We address here the regulation of the intrinsic CS variability by the expression of inactivating Kv3.3 channels in PCs by combining patch-clamp recordings and single-cell PCR methods on the same neurons, using a technique that we recently optimized to correlate single cell transcription levels with membrane ion channel electrophysiology. We show that while the inactivating TEA sensitive Kv3.3 current peak intensity increases with postnatal age, the channel density does not, arguing against postnatal developmental changes of Kv3.3b expression. Real time PCR of Kv3.3b showed a high variability from cell to cell, correlated with the Kv3.3 current density, and suggesting that there are no mechanisms regulating these currents beyond the mRNA pool. We show a significant correlation between normalized quantity of Kv3.3b mRNA and both the number of CS spikelets and their rate of voltage fluctuation, linking the intrinsic CS shape directly to the Kv3.3b mRNA pool. Comparing the observed cell-to-cell variance with studies on transcriptional noise suggests that fluctuations of the Kv3.3b mRNA pool are possibly not regulated but represent merely transcriptional noise, resulting in intrinsic variability of the CS.

  6. Cerebellar giant cell glioblastoma multiforme in an adult

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    Sudhansu Sekhar Mishra

    2014-01-01

    Full Text Available Cerebellar glioblastoma multiforme (GBM is a rare tumor that accounts for only 1% of all cases of GBM and its giant cell variant is even much rarely encountered in adults. A case of cerebellar giant cell GBM managed at our institution reporting its clinical presentation, radiological and histological findings, and treatment instituted is described. In conjunction, a literature review, including particular issues, clinical data, advances in imaging studies, pathological characteristics, treatment options, and the behavior of such malignant tumor is presented. It is very important for the neurosurgeon to make the differential diagnosis between the cerebellar GBM, and other diseases such as metastasis, anaplastic astrocytomas, and cerebellar infarct because their treatment modalities, prognosis, and outcome are different.

  7. Frequency of evident Barr and "F" corpuscles in tetraploid Purkinje neurons.

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    Zapata-Gayón, N; Márquez-Monter, H; González-Angulo, A

    1980-01-01

    A study was carried out with the purpose of establishing the frequency of female sex chromatin (Barr corpuscle) and male sex chromatin or ("F") fluorescent corpuscles in the Purkinje cerebellar neurones, that are tetraploid cells. Two Barr corpuscles were observed in 18 per cent of Purkinje cells in hematoxylin-eosin stained histological sections in five females and none in a similar number of male sex individuals. In the cerebellar smears stained according to Klinger's method, Barr corpuscles were observed in Purkinje cells in 30 per cent of females different to what was observed in male sex individuals. Smears stained with quinacrine dihydrochloride showed two "F" corpuscles in Purkinje cells of male individuals and only one fluorescent corpuscle in a lower percentage of glial cells and of the granule cell layer in this same material. "F" corpuscles were not observed in females. This study shows that in tetraploidy, as the case of Purkinje neurones, an X gonosome is expressed for each set of chromosomes in female individuals and an "F" corpuscle, corresponding to the Y gonosome of each chromosomic set is found in male sex individuals.

  8. Reevaluating the Role of LTD in Cerebellar Motor Learning

    NARCIS (Netherlands)

    M. Schonewille (Martijn); Z. Gao (Zhenyu); H.J. Boele (Henk-Jan); M.F. Vinueza Veloz (Maria); W.E. Amerika; A. Šimek (Antonia); M.T.G. Jeu (Marcel); J. Steinberg (Jordan); K. Takamiya (Kogo); F.E. Hoebeek (Freek); D. Linden (David); R. Huganir (Richard); C.I. de Zeeuw (Chris)

    2011-01-01

    textabstractLong-term depression at parallel fiber-Purkinje cell synapses (PF-PC LTD) has been proposed to be required for cerebellar motor learning. To date, tests of this hypothesis have sought to interfere with receptors (mGluR1) and enzymes (PKC, PKG, or αCamKII) necessary for induction of PF-PC

  9. Cbln1 accumulates and colocalizes with Cbln3 and GluRdelta2 at parallel fiber-Purkinje cell synapses in the mouse cerebellum.

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    Miura, Eriko; Matsuda, Keiko; Morgan, James I; Yuzaki, Michisuke; Watanabe, Masahiko

    2009-02-01

    Cbln1 (a.k.a. precerebellin) is secreted from cerebellar granule cells as homohexamer or in heteromeric complexes with Cbln3. Cbln1 plays crucial roles in regulating morphological integrity of parallel fiber (PF)-Purkinje cell (PC) synapses and synaptic plasticity. Cbln1-knockout mice display severe cerebellar phenotypes that are essentially indistinguishable from those in glutamate receptor GluRdelta2-null mice, and include severe reduction in the number of PF-PC synapses and loss of long-term depression of synaptic transmission. To understand better the relationship between Cbln1, Cbln3 and GluRdelta2, we performed light and electron microscopic immunohistochemical analyses using highly specific antibodies and antigen-exposing methods, i.e. pepsin pretreatment for light microscopy and postembedding immunogold for electron microscopy. In conventional immunohistochemistry, Cbln1 was preferentially associated with non-terminal portions of PF axons in the molecular layer but rarely overlapped with Cbln3. In contrast, antigen-exposing methods not only greatly intensified Cbln1 immunoreactivity in the molecular layer, but also revealed its high accumulation in the synaptic cleft of PF-PC synapses. No such synaptic accumulation was evident at other PC synapses. Furthermore, Cbln1 now came to overlap almost completely with Cbln3 and GluRdelta2 at PF-PC synapses. Therefore, the convergence of all three molecules provides the anatomical basis for a common signaling pathway regulating circuit development and synaptic plasticity in the cerebellum.

  10. Alterações quantitativas das células de purkinje na moléstia de chagas experimental no camundongo Quantitative study of Purkinje cells in the acute phase of experimental Chagas' disease

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    Edymar Jardim

    1967-09-01

    Full Text Available O autor estudou quantitativamente as células de Purkinje em cortes semi-seriados do cerebelo de camundongos inoculados experimentalmente com T. cruzi,tendo verificado considerável destruição neuronal na fase aguda da enfermidade.A quantitative study of Purkinje cells was done through semi-serial sections of cerebellum of mice experimentally innoculated by Trypanosoma cruzi. Avery marked neuronal destruction was found in the acute phase of Chagas' disease.

  11. Cbln1 binds to specific postsynaptic sites at parallel fiber-Purkinje cell synapses in the cerebellum.

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    Matsuda, Keiko; Kondo, Tetsuro; Iijima, Takatoshi; Matsuda, Shinji; Watanabe, Masahiko; Yuzaki, Michisuke

    2009-02-01

    Cbln1, which belongs to the C1q/tumor necrosis factor superfamily, is a unique molecule that is not only required for maintaining normal parallel fiber (PF)-Purkinje cell synapses, but is also capable of inducing new PF synapses in adult cerebellum. Although Cbln1 is reportedly released from granule cells, where and how Cbln1 binds in the cerebellum has remained largely unclear, partly because Cbln1 undergoes proteolysis to yield various fragments that are differentially detected by different antibodies. To circumvent this problem, we characterized the Cbln1-binding site using recombinant Cbln1. An immunohistochemical analysis revealed that recombinant Cbln1 preferentially bound to PF-Purkinje cell synapses in primary cultures and acute slice preparations in a saturable and replaceable manner. Specific binding was observed for intact Cbln1 that had formed a hexamer, but not for the N-terminal or C-terminal fragments of Cbln1 fused to other proteins. Similarly, mutant Cbln1 that had formed a trimer did not bind to the Purkinje cells. Immunoreactivity for the recombinant Cbln1 was observed in weaver cerebellum (which lacks granule cells) but was absent in pcd cerebellum (which lacks Purkinje cells), suggesting that the binding site was located on the postsynaptic sites of PF-Purkinje cell synapses. Finally, a subcellular fractionation analysis revealed that recombinant Cbln1 bound to the synaptosomal and postsynaptic density fractions. These results indicate that Cbln1, released from granule cells as hexamers, specifically binds to a putative receptor located at the postsynaptic sites of PF-Purkinje cell synapses, where it induces synaptogenesis.

  12. Developmental expression and differentiation-related neuron-specific splicing of metastasis suppressor 1 (Mtss1 in normal and transformed cerebellar cells

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    Baader Stephan L

    2007-10-01

    Full Text Available Abstract Background Mtss1 encodes an actin-binding protein, dysregulated in a variety of tumors, that interacts with sonic hedgehog/Gli signaling in epidermal cells. Given the prime importance of this pathway for cerebellar development and tumorigenesis, we assessed expression of Mtss1 in the developing murine cerebellum and human medulloblastoma specimens. Results During development, Mtss1 is transiently expressed in granule cells, from the time point they cease to proliferate to their synaptic integration. It is also expressed by granule cell precursor-derived medulloblastomas. In the adult CNS, Mtss1 is found exclusively in cerebellar Purkinje cells. Neuronal differentiation is accompanied by a switch in Mtss1 splicing. Whereas immature granule cells express a Mtss1 variant observed also in peripheral tissues and comprising exon 12, this exon is replaced by a CNS-specific exon, 12a, in more mature granule cells and in adult Purkinje cells. Bioinformatic analysis of Mtss1 suggests that differential exon usage may affect interaction with Fyn and Src, two tyrosine kinases previously recognized as critical for cerebellar cell migration and histogenesis. Further, this approach led to the identification of two evolutionary conserved nuclear localization sequences. These overlap with the actin filament binding site of Mtss1, and one also harbors a potential PKA and PKC phosphorylation site. Conclusion Both the pattern of expression and splicing of Mtss1 is developmentally regulated in the murine cerebellum. These findings are discussed with a view on the potential role of Mtss1 for cytoskeletal dynamics in developing and mature cerebellar neurons.

  13. STD-dependent and independent encoding of input irregularity as spike rate in a computational model of a cerebellar nucleus neuron.

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    Luthman, Johannes; Hoebeek, Freek E; Maex, Reinoud; Davey, Neil; Adams, Rod; De Zeeuw, Chris I; Steuber, Volker

    2011-12-01

    Neurons in the cerebellar nuclei (CN) receive inhibitory inputs from Purkinje cells in the cerebellar cortex and provide the major output from the cerebellum, but their computational function is not well understood. It has recently been shown that the spike activity of Purkinje cells is more regular than previously assumed and that this regularity can affect motor behaviour. We use a conductance-based model of a CN neuron to study the effect of the regularity of Purkinje cell spiking on CN neuron activity. We find that increasing the irregularity of Purkinje cell activity accelerates the CN neuron spike rate and that the mechanism of this recoding of input irregularity as output spike rate depends on the number of Purkinje cells converging onto a CN neuron. For high convergence ratios, the irregularity induced spike rate acceleration depends on short-term depression (STD) at the Purkinje cell synapses. At low convergence ratios, or for synchronised Purkinje cell input, the firing rate increase is independent of STD. The transformation of input irregularity into output spike rate occurs in response to artificial input spike trains as well as to spike trains recorded from Purkinje cells in tottering mice, which show highly irregular spiking patterns. Our results suggest that STD may contribute to the accelerated CN spike rate in tottering mice and they raise the possibility that the deficits in motor control in these mutants partly result as a pathological consequence of this natural form of plasticity.

  14. A cell model study of calcium influx mechanism regulated by calcium-dependent potassium channels in Purkinje cell dendrites.

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    Chono, Koji; Takagi, Hiroshi; Koyama, Shozo; Suzuki, Hideo; Ito, Etsuro

    2003-10-30

    The present study was designed to elucidate the roles of dendritic voltage-gated K+ channels in Ca2+ influx mechanism of a rat Purkinje cell using a computer simulation program. First, we improved the channel descriptions and the maximum conductance in the Purkinje cell model to mimic both the kinetics of ion channels and the Ca2+ spikes, which had failed in previous studies. Our cell model is, therefore, much more authentic than those in previous studies. Second, synaptic inputs that mimic stimulation of parallel fibers and induce sub-threshold excitability were simultaneously applied to the spiny dendrites. As a result, transient Ca2+ responses were observed in the stimulation points and they decreased with the faster decay rate in the cell model including high-threshold Ca2+-dependent K+ channels than in those excluding these channels. Third, when a single synaptic input was applied into a spiny dendrite, Ca2+-dependent K+ channels suppressed Ca2+ increases at stimulation and recording points. Finally, Ca2+-dependent K+ channels were also found to suppress the time to peak Ca2+ values in the recording points. These results suggest that the opening of Ca2+-dependent K+ channels by Ca2+ influx through voltage-gated Ca2+ channels hyperpolarizes the membrane potentials and deactivates these Ca2+ channels in a negative feedback manner, resulting in local, weak Ca2+ responses in spiny dendrites of Purkinje cells.

  15. Eph receptors are involved in the activity-dependent synaptic wiring in the mouse cerebellar cortex.

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    Roberta Cesa

    Full Text Available Eph receptor tyrosine kinases are involved in many cellular processes. In the developing brain, they act as migratory and cell adhesive cues while in the adult brain they regulate dendritic spine plasticity. Here we show a new role for Eph receptor signalling in the cerebellar cortex. Cerebellar Purkinje cells are innervated by two different excitatory inputs. The climbing fibres contact the proximal dendritic domain of Purkinje cells, where synapse and spine density is low; the parallel fibres contact the distal dendritic domain, where synapse and spine density is high. Interestingly, Purkinje cells have the intrinsic ability to generate a high number of spines over their entire dendritic arborisations, which can be innervated by the parallel fibres. However, the climbing fibre input continuously exerts an activity-dependent repression on parallel fibre synapses, thus confining them to the distal Purkinje cell dendritic domain. Such repression persists after Eph receptor activation, but is overridden by Eph receptor inhibition with EphA4/Fc in neonatal cultured cerebellar slices as well as mature acute cerebellar slices, following in vivo infusion of the EphA4/Fc inhibitor and in EphB receptor-deficient mice. When electrical activity is blocked in vivo by tetrodotoxin leading to a high spine density in Purkinje cell proximal dendrites, stimulation of Eph receptor activation recapitulates the spine repressive effects of climbing fibres. These results suggest that Eph receptor signalling mediates the repression of spine proliferation induced by climbing fibre activity in Purkinje cell proximal dendrites. Such repression is necessary to maintain the correct architecture of the cerebellar cortex.

  16. Modulation by K+ channels of action potential-evoked intracellular Ca2+ concentration rises in rat cerebellar basket cell axons.

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    Tan, Y P; Llano, I

    1999-10-01

    1. Action potential-evoked [Ca2+]i rises in basket cell axons of rat cerebellar slices were studied using two-photon laser scanning microscopy and whole-cell recording, to identify the K+ channels controlling the shape of the axonal action potential. 2. Whole-cell recordings of Purkinje cell IPSCs were used to screen K+ channel subtypes which could contribute to axonal repolarization. alpha-Dendrotoxin, 4-aminopyridine, charybdotoxin and tetraethylammonium chloride increased IPSC rate and/or amplitude, whereas iberiotoxin and apamin failed to affect the IPSCs. 3. The effects of those K+ channel blockers that enhanced transmitter release on the [Ca2+]i rises elicited in basket cell axons by action potentials fell into three groups: 4-aminopyridine strongly increased action potential-evoked [Ca2+]i; tetraethylammonium and charybdotoxin were ineffective alone but augmented the effects of 4-aminopyridine; alpha-dendrotoxin had no effect. 4. We conclude that cerebellar basket cells contain at least three pharmacologically distinct K+ channels, which regulate transmitter release through different mechanisms. 4-Aminopyridine-sensitive, alpha-dendrotoxin-insensitive K+ channels are mainly responsible for repolarization in basket cell presynaptic terminals. K+ channels blocked by charybdotoxin and tetraethylammonium have a minor role in repolarization. alpha-Dendrotoxin-sensitive channels are not involved in shaping the axonal action potential waveform. The two last types of channels must therefore exert control of synaptic activity through a pathway unrelated to axonal action potential broadening.

  17. Topography of Purkinje cells and other calbindin-immunoreactive cells within adult and hatchling turtle cerebellum.

    Science.gov (United States)

    Ariel, Michael; Ward, Kyle C; Tolbert, Daniel L

    2009-12-01

    The turtle's cerebellum (Cb) is an unfoliated sheet, so the topography of its entire cortex can be easily studied physiologically by optical recordings. However, unlike the mammalian Cb, little is known about the topography of turtle Purkinje cells (PCs). Here, topography was examined using calbindin-D(28K) immunohistochemistry of adult and hatchling turtles (Trachemys scripta elegans, 2.5-15 cm carapace length). Each Cb was flattened between two Sylgard sheets and fixed in paraformaldehyde. Sections (52 microm thick) were cut parallel to the flattened cortex (tangential), resulting in calbindin-immunolabeled PCs being localized to three to six sections for each turtle. PC position and size were quantified using Neurolucida Image Analysis system. Although hatchling Cb were medial-laterally narrower (3.0 vs. 6.5 mm) and rostral-caudally shorter (2.5 vs. 5.5 mm) than adult Cb, both averaged near 15,000 PCs distributed uniformly. Hatchling PCs were smaller than adult PCs (178 vs. 551 microm(2)) and more densely packed (2,180 vs. 625 cells/mm(2)). Calbindin immunoreactivity also labeled non-PCs along the Cb's marginal rim and its caudal pole. Many of these were very small (22.9 microm(2)) ovoid-shaped cells clustered together, possibly proliferating external granule layer cells. Other labeled cells were larger and fusiform-shaped (12.6 x 33.4 microm) adjacent to inner granule cells along the marginal rim, suggestive of migrating cells. It is not known whether these are new neurons being generated within the adult and hatchling Cb and if they connect to efferent and afferent paths. Based on these anatomical findings, we suggest that unique physiological features may exist along the rim of the turtle Cb.

  18. Dose response relationship of disturbed migration of Purkinje cells in the cerebellum due to X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Darmanto, W.; Inouye, Minoru; Hayasaka, Shizu; Takagishi, Yoshiko; Aolad, H.; Murata, Yoshiharu [Nagoya Univ. (Japan). Research Inst. of Environmental Medicine

    1998-10-01

    Pregnant rats were exposed to 2.0, 2.25 or 2.5 Gy X-irradiation on gestation day 21. Pups were sacrificed 12 hr after exposure, and on postnatal day 5 (P5), P7 and P9. Their cerebella were observed immunohistochemically using anti-inositol 1,4,5 triphosphate (IP3) receptor antibody to identify Purkinje cells. These cells were disturbed to migrate and remained in the internal granular layer and white matter of the cerebellum. They had short dendrites, and some showed an abnormal direction of dendrites in rats exposed to 2.25 or 2.5 Gy. Alignment of Purkinje cells was also disturbed when examined either on P5, P7 or P9 especially by doses of 2.25 and 2.5 Gy. There was a relationship between X-ray doses and the number of cells piling up in the Purkinje cell layer of the cerebellum. The dose-response relationship with the number of ectopic Purkinje cells was noted in the anterior lobes of the cerebellum. (author)

  19. Silencing the Majority of Cerebellar Granule Cells Uncovers Their Essential Role in Motor Learning and Consolidation

    Directory of Open Access Journals (Sweden)

    Elisa Galliano

    2013-04-01

    Full Text Available Cerebellar granule cells (GCs account for more than half of all neurons in the CNS of vertebrates. Theoretical work has suggested that the abundance of GCs is advantageous for sparse coding during memory formation. Here, we minimized the output of the majority of GCs by selectively eliminating their CaV2.1 (P/Q-type Ca2+ channels, which mediate the bulk of their neurotransmitter release. This resulted in reduced GC output to Purkinje cells (PCs and stellate cells (SCs as well as in impaired long-term plasticity at GC-PC synapses. As a consequence modulation amplitude and regularity of simple spike (SS output were affected. Surprisingly, the overall motor performance was intact, whereas demanding motor learning and memory consolidation tasks were compromised. Our findings indicate that a minority of functionally intact GCs is sufficient for the maintenance of basic motor performance, whereas acquisition and stabilization of sophisticated memories require higher numbers of normal GCs controlling PC firing.

  20. Prophylactic role of melatonin against radiation induced damage in mouse cerebellum with special reference to Purkinje cells

    Energy Technology Data Exchange (ETDEWEB)

    Sisodia, Rashmi; Kumari, Seema; Verma, Rajesh Kumar; Bhatia, A L [Neurobiology Laboratory, Department of Zoology, University of Rajasthan, Jaipur 302004 (India)

    2006-06-15

    Melatonin, a hormone with a proven antioxidative efficacy, crosses all morphophysiological barriers, including the blood-brain barrier, and distributes throughout the cell. The present study is an attempt to investigate the prophylactic influence of a chronic low level of melatonin against an acute radiation induced oxidative stress in the cerebellum of Swiss albino mice, with special reference to Purkinje cells. After 15 days of treatment the mice were sacrificed at various intervals from 1 to 30 days. Biochemical parameters included lipid peroxidation (LPO) and glutathione (GSH) levels as the endpoints. The quantitative study included alterations in number and volume of Purkinje cells. Swiss albino mice were orally administered a very low dose of melatonin (0.25 mg/mouse/day) for 15 consecutive days before single exposure to 4 Gy gamma radiation. Melatonin checked the augmented levels of LPO, by approximately 55%, by day 30 day post-exposure. Radiation induced depleted levels of GSH could be raised by 68.9% by day 30 post-exposure. Radiation exposure resulted in a reduction of the volume of Purkinje cells and their total number. The administration of melatonin significantly protected against the radiation induced decreases in Purkinje cell volume and number. Results indicate the antioxidative properties of melatonin resulting in its prophylactic property against radiation induced biochemical and cellular alterations in the cerebellum. The findings support the idea that melatonin may be used as an anti-irradiation drug due to its potent free radical scavenging and antioxidative efficacy.

  1. Quantitative organization of GABAergic synapses in the molecular layer of the mouse cerebellar cortex.

    Directory of Open Access Journals (Sweden)

    Federica Briatore

    Full Text Available In the cerebellar cortex, interneurons of the molecular layer (stellate and basket cells provide GABAergic input to Purkinje cells, as well as to each other and possibly to other interneurons. GABAergic inhibition in the molecular layer has mainly been investigated at the interneuron to Purkinje cell synapse. In this study, we used complementary subtractive strategies to quantitatively assess the ratio of GABAergic synapses on Purkinje cell dendrites versus those on interneurons. We generated a mouse model in which the GABAA receptor alpha1 subunit (GABAARalpha1 was selectively removed from Purkinje cells using the Cre/loxP system. Deletion of the alpha1 subunit resulted in a complete loss of GABAAR aggregates from Purkinje cells, allowing us to determine the density of GABAAR clusters in interneurons. In a complementary approach, we determined the density of GABA synapses impinging on Purkinje cells using alpha-dystroglycan as a specific marker of inhibitory postsynaptic sites. Combining these inverse approaches, we found that synapses received by interneurons represent approximately 40% of all GABAergic synapses in the molecular layer. Notably, this proportion was stable during postnatal development, indicating synchronized synaptogenesis. Based on the pure quantity of GABAergic synapses onto interneurons, we propose that mutual inhibition must play an important, yet largely neglected, computational role in the cerebellar cortex.

  2. Studying cerebellar circuits by remote control of selected neuronal types with GABA-A receptors

    Directory of Open Access Journals (Sweden)

    William Wisden

    2009-12-01

    Full Text Available Although GABA-A receptor-mediated inhibition of cerebellar Purkinje cells by molecular layer interneurons (MLIs has been studied intensely on the cellular level, it has remained unclear how this inhibition regulates cerebellum-dependent behaviour. We have implemented two complementary approaches to investigate the function of the MLI-Purkinje cell synapse on the behavioral level. In the first approach we permanently disrupted inhibitory fast synaptic transmission at the synapse by genetically removing the postsynaptic GABA-A receptors from Purkinje cells (PC-Δγ2 mice. We found that chronic disruption of the MLI-Purkinje cell synapse strongly impaired cerebellar learning of the vestibular occular reflex (VOR, presumably by disrupting the temporal patterns of Purkinje cell activity. However, in PC-Δγ2 mice the baseline VOR reflex was only mildly affected; indeed PC-Δγ2 mice showed no ataxia or gait abnormalities suggesting that MLI control of Purkinje cell activity is either not involved in ongoing motor tasks or that the system has found a way to compensate for its loss. To investigate the latter possibility we have developed an alternative genetic technique; we made the MLI-Purkinje cell synapse selectively sensitive to rapid manipulation with the GABAA receptor modulator zolpidem (PC-γ2-swap mice. Minutes after intraperitoneal zolpidem injection, these PC-γ2-swap mice developed severe motor abnormalities, revealing a substantial contribution of the MLI-Purkinje cell synapse to real time motor control. The cell-type selective permanent knockout of synaptic GABAergic input, and the fast reversible modulation of GABAergic input at the same synapse illustrate how pursuing both strategies gives a fuller view.

  3. Evolving Models of Pavlovian Conditioning: Cerebellar Cortical Dynamics in Awake Behaving Mice

    NARCIS (Netherlands)

    M. tenBrinke (MichielM.); H.J. Boele (Henk-Jan); J.K. Spanke (Jochen); J.W. Potters (Jan Willem); K. Kornysheva (Katja); P. Wulff (Peer); A.C.H.G. IJpelaar (Anna C.H.G.); S.K.E. Koekkoek (Bas); C.I. DeZeeuw (Chris)

    2015-01-01

    textabstractThree decades of electrophysiological research on cerebellar cortical activity underlying Pavlovian conditioning have expanded our understanding of motor learning in the brain. Purkinje cell simple spike suppression is considered to be crucial in the expression of conditional blink respo

  4. Acid-sensitive channel inhibition prevents fetal alcohol spectrum disorders cerebellar Purkinje cell loss

    OpenAIRE

    Ramadoss, Jayanth; Lunde, Emilie R.; Ouyang, Nengtai; Chen, Wei-Jung A.; Cudd, Timothy A.

    2008-01-01

    Ethanol is now considered the most common human teratogen. Educational campaigns have not reduced the incidence of ethanol-mediated teratogenesis, leading to a growing interest in the development of therapeutic prevention or mitigation strategies. On the basis of the observation that maternal ethanol consumption reduces maternal and fetal pH, we hypothesized that a pH-sensitive pathway involving the TWIK-related acid-sensitive potassium channels (TASKs) is implicated in ethanol-induced injury...

  5. Cause and Consequence of Purkinje Cell Signals in the Cerebellar Flocculus

    NARCIS (Netherlands)

    B.H.J. Winkelman (Beerend)

    2015-01-01

    markdownabstract__Abstract__ How environmental stimuli are processed by neural circuits and how neural circuits control behavior are fundamental questions in systems neuroscience, describing both ends of its research spectrum. At one end, neural structures can be identified that are dedicated to th

  6. Multiple subclasses of Purkinje cells in the primate floccular complex provide similar signals to guide learning in the vestibulo-ocular reflex

    Science.gov (United States)

    Raymond, J. L.; Lisberger, S. G.

    1997-01-01

    The neural "learning rules" governing the induction of plasticity in the cerebellum were analyzed by recording the patterns of neural activity in awake, behaving animals during stimuli that induce a form of cerebellum-dependent learning. We recorded the simple- and complex-spike responses of a broad sample of Purkinje cells in the floccular complex during a number of stimulus conditions that induce motor learning in the vestibulo-ocular reflex (VOR). Each subclass of Purkinje cells carried essentially the same information about required changes in the gain of the VOR. The correlation of simple-spike activity in Purkinje cells with activity in vestibular pathways could guide learning during low-frequency but not high-frequency stimuli. Climbing fiber activity could guide learning during all stimuli tested but only if compared with the activity present approximately 100 msec earlier in either vestibular pathways or Purkinje cells.

  7. Development of the cerebellar cortex in the mouse

    Institute of Scientific and Technical Information of China (English)

    Xiangshu Cheng; Jin Du; Dongming Yu; Qiying Jiang; Yanqiu Hu; Lei Wang; Mingshan Li; Jinbo Deng

    2011-01-01

    The cerebellum is a highly conserved structure in the central nervous system of vertebrates, and is involved in the coordination of voluntary motor behavior. Supporting this function, the cerebellar cortex presents a layered structure which requires precise spatial and temporal coordination of proliferation, migration, differentiation, and apoptosis events. The formation of the layered structure in the developing cerebellum remains unclear. The present study investigated the development of the cerebellar cortex. The results demonstrate that the primordium of the cerebellum comprises the ependymal, mantle, and marginal layers at embryonic day 12 (E12). Subsequently, the laminated cerebellar cortex undergoes cell proliferation, differentiation, and migration, and at about postnatal day 0 (P0), the cerebellar cortex presents an external granular layer, a molecular layer, a Purkinje layer, and an internal granular layer. The external granular layer is thickest at P6/7 and disappears at P20. From P0 to P30, the internal granular cells and the Purkinje cells gradually differentiate and develop until maturity. Apoptotic neurons are evident in the layered structure in the developing cerebellar cortex. The external granular layer disappears gradually because of cell migration and apoptosis. The cells of the other layers primarily undergo differentiation, development, and apoptosis.

  8. Mitotic Events in Cerebellar Granule Progenitor Cells that Expand Cerebellar Surface Area Are Critical for Normal Cerebellar Cortical Lamination in Mice

    Science.gov (United States)

    Chang, Joshua C.; Leung, Mark; Gokozan, Hamza Numan; Gygli, Patrick Edwin; Catacutan, Fay Patsy; Czeisler, Catherine; Otero, José Javier

    2015-01-01

    Late embryonic and postnatal cerebellar folial surface area expansion promotes cerebellar cortical cytoarchitectural lamination. We developed a streamlined sampling scheme to generate unbiased estimates of murine cerebellar surface area and volume using stereological principles. We demonstrate that during the proliferative phase of the external granule layer (EGL) and folial surface area expansion, EGL thickness does not change and thus is a topological proxy for progenitor self-renewal. The topological constraints indicate that during proliferative phases, migration out of the EGL is balanced by self-renewal. Progenitor self-renewal must, therefore, include mitotic events yielding either 2 cells in the same layer to increase surface area (β-events) and mitotic events yielding 2 cells, with 1 cell in a superficial layer and 1 cell in a deeper layer (α-events). As the cerebellum grows, therefore, β-events lie upstream of α-events. Using a mathematical model constrained by the measurements of volume and surface area, we could quantify inter-mitotic times for β-events on a per-cell basis in post-natal mouse cerebellum. Furthermore, we found that loss of CCNA2, which decreases EGL proliferation and secondarily induces cerebellar cortical dyslamination, shows preserved α-type events. Thus, CCNA2-null cerebellar granule progenitor cells are capable of self-renewal of the EGL stem cell niche; this is concordant with prior findings of extensive apoptosis in CCNA2-null mice. Similar methodologies may provide another layer of depth to the interpretation of results from stereological studies. PMID:25668568

  9. Developmental Hypothyroxinemia and Hypothyroidism Reduce Parallel Fiber-Purkinje Cell Synapses in Rat Offspring by Downregulation of Neurexin1/Cbln1/GluD2 Tripartite Complex.

    Science.gov (United States)

    Wang, Yuan; Dong, Jing; Wang, Yi; Wei, Wei; Song, Binbin; Shan, Zhongyan; Teng, Weiping; Chen, Jie

    2016-10-01

    Iodine is a significant micronutrient. Iodine deficiency (ID)-induced hypothyroxinemia and hypothyroidism during developmental period can cause cerebellar dysfunction. However, mechanisms are still unclear. Therefore, the present research aims to study effects of developmental hypothyroxinemia caused by mild ID and hypothyroidism caused by severe ID or methimazole (MMZ) on parallel fiber-Purkinje cell (PF-PC) synapses in filial cerebellum. Maternal hypothyroxinemia and hypothyroidism models were established in Wistar rats using ID diet and deionized water supplemented with different concentrations of potassium iodide or MMZ water. Birth weight and cerebellum weight were measured. We also examined PF-PC synapses using immunofluorescence, and western blot analysis was conducted to investigate the activity of Neurexin1/cerebellin1 (Cbln1)/glutamate receptor d2 (GluD2) tripartite complex. Our results showed that hypothyroxinemia and hypothyroidism decreased birth weight and cerebellum weight and reduced the PF-PC synapses on postnatal day (PN) 14 and PN21. Accordingly, the mean intensity of vesicular glutamate transporter (VGluT1) and Calbindin immunofluorescence was reduced in mild ID, severe ID, and MMZ groups. Moreover, maternal hypothyroxinemia and hypothyroidism reduced expression of Neurexin1/Cbln1/GluD2 tripartite complex. Our study supports the hypothesis that developmental hypothyroxinemia and hypothyroidism reduce PF-PC synapses, which may be attributed to the downregulation of Neurexin1/Cbln1/GluD2 tripartite complex.

  10. Purkinje cell activity during classical conditioning with different conditional stimuli explains central tenet of Rescorla–Wagner model [corrected].

    Science.gov (United States)

    Rasmussen, Anders; Zucca, Riccardo; Johansson, Fredrik; Jirenhed, Dan-Anders; Hesslow, Germund

    2015-11-10

    A central tenet of Rescorla and Wagner's model of associative learning is that the reinforcement value of a paired trial diminishes as the associative strength between the presented stimuli increases. Despite its fundamental importance to behavioral sciences, the neural mechanisms underlying the model have not been fully explored. Here, we present findings that, taken together, can explain why a stronger association leads to a reduced reinforcement value, within the context of eyeblink conditioning. Specifically, we show that learned pause responses in Purkinje cells, which trigger adaptively timed conditioned eyeblinks, suppress the unconditional stimulus (US) signal in a graded manner. Furthermore, by examining how Purkinje cells respond to two distinct conditional stimuli and to a compound stimulus, we provide evidence that could potentially help explain the somewhat counterintuitive overexpectation phenomenon, which was derived from the Rescorla-Wagner model.

  11. The Changeable Nervous System: Studies On Neuroplasticity In Cerebellar Cultures

    Science.gov (United States)

    Seil, Fredrick J.

    2014-01-01

    Circuit reorganization after injury was studied in a cerebellar culture model. When cerebellar cultures derived from newborn mice were exposed at explantation to a preparation of cytosine arabinoside that destroyed granule cells and oligodendrocytes and compromised astrocytes, Purkinje cells surviving in greater than usual numbers were unensheathed by astrocytic processes and received twice the control number of inhibitory axosomatic synapses. Purkinje cell axon collaterals sprouted and many of their terminals formed heterotypical synapses with other Purkinje cell dendritic spines. The resulting circuit reorganization preserved inhibition in the cerebellar cortex. Following this reorganization, replacement of the missing granule cells and glia was followed by a restitution of the normal circuitry. Most of these developmental and reconstructive changes were not dependent on neuronal activity, the major exception being inhibitory synaptogenesis. The full complement of inhibitory synapses did not develop in the absence of neuronal activity, which could be mitigated by application of exogenous TrkB receptor ligands. Inhibitory synaptogenesis could also be promoted by activity-induced release of endogenous TrkB receptor ligands or by antibody activation of the TrkB receptor. PMID:24933693

  12. Cerebellar clear cell ependymoma in a 10 year old girl

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    Thinzar Aye Nyein; Moon, Ah Rim; Hwang, Sun Chul; Hong, Hyun Sook; Lee, A Leum; Chang, Kee Hyun; Kim, Hee Kyung; Chin, Su Sie [Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of); Park, Ji Sang [Soonchunhyang University Gumi Hospital, Gumi (Korea, Republic of)

    2016-01-15

    Clear cell ependymoma (CCE) is a histological rare variant (1–5%) of ependymoma, which is distinguished from other histological subtypes by the presence of fusiform cells arrayed radially around small blood vessels. These alleged perivascular pseudorosettes are significant characteristic features of ependymomas. About 95% of infratentorial ependymomas are found in the fourth ventricle and the remainder occurs as cerebellopontine angle lesions. In previous reports, the cerebellum is found to be a rare location for ependymoma. In this study we report one case of CCE originating from the cerebellar hemisphere, showing unusual morphology on 3T MRI.

  13. Prenatal infection decreases calbindin, decreases Purkinje cell volume and density and produces long-term motor deficits in Sprague-Dawley rats.

    Science.gov (United States)

    Wallace, K; Veerisetty, S; Paul, I; May, W; Miguel-Hidalgo, J J; Bennett, W

    2010-01-01

    The cerebellum is involved in the control of motor functions with Purkinje cells serving as the only output from the cerebellum. Purkinje cells are important targets for toxic substances and are vulnerable to prenatal insults. Intrauterine infection (IUI) has been shown to selectively target the developing cerebral white matter through lesioning, necrosis and inflammatory cytokine activation. Developmental and cognitive delays have been associated with animal models of IUI. The aim of this study was to determine if IUI leads to damage to Purkinje cells in the developing cerebellum and if any damage is associated with decreases in calbindin and motor behaviors in surviving pups. Pregnant rats were injected with Escherichia coli (1 × 10⁵ colony-forming units) or sterile saline at gestational day 17. Beginning at postnatal day (PND) 2, the pups were subjected to a series of developmental tests to examine developmental milestones. At PND 16, some pups were sacrificed and their brains extracted and processed for histology or protein studies. Hematoxylin and eosin (HE) staining was done to examine the general morphology of the Purkinje cells and to examine Purkinje cell density, area and volume. Calbindin expression was examined in the cerebellum via immunohistochemistry and Western blot techniques. The remaining rat pups were used to examine motor coordination and balance on a rotating rotarod at the prepubertal and adult ages. Prenatal E. coli injection did not significantly change birth weight or delivery time, but did delay surface righting and negative geotaxis in pups. Pups in the E. coli group also had a decrease in the number of Purkinje cells, as well as a decrease in Purkinje cell density and volume. HE staining demonstrated a change in Purkinje cell morphology. Calbindin expression was decreased in rats from the E. coli group as well. Locomotor tests indicated that while there were no significant changes in gross motor activity, motor coordination and

  14. A cerebellar learning model of vestibulo-ocular reflex adaptation in wild-type and mutant mice

    NARCIS (Netherlands)

    Clopath, Claudia; Badura, Aleksandra; De Zeeuw, Chris I; Brunel, Nicolas

    2014-01-01

    Mechanisms of cerebellar motor learning are still poorly understood. The standard Marr-Albus-Ito theory posits that learning involves plasticity at the parallel fiber to Purkinje cell synapses under control of the climbing fiber input, which provides an error signal as in classical supervised learni

  15. Interaction of Kv3 potassium channels and resurgent sodium current influences the rate of spontaneous firing of Purkinje neurons.

    Science.gov (United States)

    Akemann, Walther; Knöpfel, Thomas

    2006-04-26

    Purkinje neurons spontaneously generate action potentials in the absence of synaptic drive and thereby exert a tonic, yet plastic, input to their target cells in the deep cerebellar nuclei. Purkinje neurons express two ionic currents with biophysical properties that are specialized for high-frequency firing: resurgent sodium currents and potassium currents mediated by Kv3.3. How these ionic currents determine the intrinsic activity of Purkinje neurons has only partially been understood. Purkinje neurons from mutant mice lacking Kv3.3 have a reduced rate of spontaneous firing. Dynamic-clamp recordings demonstrated that normal firing rates are rescued by inserting artificial Kv3 currents into Kv3.3 knock-out Purkinje neurons. Numerical simulations indicated that Kv3.3 increases the spontaneous firing rate via cooperation with resurgent sodium currents. We conclude that the rate of spontaneous action potential firing of Purkinje neurons is controlled by the interaction of Kv3.3 potassium currents and resurgent sodium currents.

  16. Cerebellar network plasticity: from genes to fast oscillation.

    Science.gov (United States)

    Cheron, G; Servais, L; Dan, B

    2008-04-22

    The role of the cerebellum has been increasingly recognized not only in motor control but in sensory, cognitive and emotional learning and regulation. Purkinje cells, being the sole output from the cerebellar cortex, occupy an integrative position in this network. Plasticity at this level is known to critically involve calcium signaling. In the last few years, electrophysiological study of genetically engineered mice has demonstrated the topical role of several genes encoding calcium-binding proteins (calretinin, calbindin, parvalbumin). Specific inactivation of these genes results in the emergence of a fast network oscillation (ca. 160 Hz) throughout the cerebellar cortex in alert animals, associated with ataxia. This oscillation is produced by synchronization of Purkinje cells along the parallel fiber beam. It behaves as an electrophysiological arrest rhythm, being blocked by sensorimotor stimulation. Pharmacological manipulations showed that the oscillation is blocked by GABA(A) and NMDA antagonists as well as gap junction blockers. This cerebellar network oscillation has also been documented in mouse models of human conditions with complex developmental cerebellar dysfunction, such as Angelman syndrome and fetal alcohol syndrome. Recent evidence suggests a relationship between fast oscillation and cerebellar long term depression (LTD). This may have major implications for future therapeutic targeting.

  17. Antenatal betamethasone produces protracted changes in anxiety-like behaviors and in the expression of microtubule-associated protein 2, brain-derived neurotrophic factor and the tyrosine kinase B receptor in the rat cerebellar cortex.

    Science.gov (United States)

    Pascual, Rodrigo; Valencia, Martina; Bustamante, Carlos

    2015-06-01

    Using classic Golgi staining methods, we previously showed that the administration of synthetic glucocorticoid betamethasone in equivalent doses to those given in cases of human premature birth generates long-term alterations in Purkinje cell dendritic development in the cerebellar cortex. In the present study, we evaluated whether betamethasone alters the immunohistochemical expression of proteins that participate in cerebellar Purkinje cell dendritic development and maintenance, including microtubule-associated protein 2 (MAP2), brain-derived neurotrophic factor (BDNF) and the tyrosine kinase B receptor (TrkB), which are located predominantly in the cerebellar molecular layer where Purkinje cell dendritogenesis occurs. Consistent with our previous Golgi stain studies, we observed that animals prenatally exposed to a single course of betamethasone showed long-term alterations in the expression of MAP2, BDNF and TrkB. Additionally, these protracted molecular changes were accompanied by anxiety-like behaviors in the elevated plus maze and marble burying tests.

  18. Ethanol-Induced Cerebellar Ataxia: Cellular and Molecular Mechanisms.

    Science.gov (United States)

    Dar, M Saeed

    2015-08-01

    The cerebellum is an important target of ethanol toxicity given that cerebellar ataxia is the most consistent physical manifestation of acute ethanol consumption. Despite the significance of the cerebellum in ethanol-induced cerebellar ataxia (EICA), the cellular and molecular mechanisms underlying EICA are incompletely understood. However, two important findings have shed greater light on this phenomenon. First, ethanol-induced blockade of cerebellar adenosine uptake in rodent models points to a role for adenosinergic A1 modulation of EICA. Second, the consistent observation that intracerebellar administration of nicotine in mice leads to antagonism of EICA provides evidence for a critical role of cerebellar nitric oxide (NO) in EICA reversal. Based on these two important findings, this review discusses the potential molecular events at two key synaptic sites (mossy fiber-granule cell-Golgi cell (MGG synaptic site) and granule cell parallel fiber-Purkinje cell (GPP synaptic site) that lead to EICA. Specifically, ethanol-induced neuronal NOS inhibition at the MGG synaptic site acts as a critical trigger for Golgi cell activation which leads to granule cell deafferentation. Concurrently, ethanol-induced inhibition of adenosine uptake at the GPP synaptic site produces adenosine accumulation which decreases glutamate release and leads to the profound activation of Purkinje cells (PCs). These molecular events at the MGG and GPP synaptic sites are mutually reinforcing and lead to cerebellar dysfunction, decreased excitatory output of deep cerebellar nuclei, and EICA. The critical importance of PCs as the sole output of the cerebellar cortex suggests normalization of PC function could have important therapeutic implications.

  19. Primary cerebellar extramedullary myeloid cell tumor mimicking oligodendroglioma.

    Science.gov (United States)

    Ho, D M; Wong, T T; Guo, W Y; Chang, K P; Yen, S H

    1997-10-01

    Extramedullary myeloid cell tumors (EMCTs) are tumors consisting of immature cells of the myeloid series that occur outside the bone marrow. Most of them are associated with acute myelogenous leukemia or other myeloproliferative disorders, and a small number occur as primary lesions, i.e., are not associated with hematological disorders. Occurrence inside the cranium is rare, and there has been only one case of primary EMCT involving the cerebellum reported in the literature. The case we report here is a blastic EMCT occurring in the cerebellum of a 3-year-old boy who had no signs of leukemia or any hematological disorder throughout the entire course. The cerebellar tumor was at first misdiagnosed as an "oligodendroglioma" because of the uniformity and "fried egg" artifact of the tumor cells. The tumor disappeared during chemotherapy consisting of 12 treatments. However, it recurred and metastasized to the cerebrospinal fluid (CSF) shortly after the therapy was completed. A diagnosis of EMCT was suspected because of the presence of immature myeloid cells in the CSF, and was confirmed by anti-myeloperoxidase and anti-lysozyme immunoreactivity of the cerebellar tumor. The patient succumbed 1 year and 3 months after the first presentation of the disease.

  20. Congenital Cerebellar Mixed Germ Cell Tumor Presenting with Hemorrhage in a Newborn

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Mok; Kim, Ji Hye; Yoo, So Young; Park, Won Soon; Jang, Yun Sil; Shin, Hyung Jin; Suh, Yeon Lim [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2008-07-15

    We report here on a neonate with congenital cerebellar mixed germ cell tumor, and this initially presented as cerebellar hemorrhage. Postnatal cranial ultrasonography revealed an echogenic cerebellar mass that exhibited the signal characteristics of hemorrhage rather than tumor on MR images. The short-term follow-up images also suggested a resolving cerebellar hemorrhage. One month later, the neonate developed vomiting. A second set of MR images demonstrated an enlarged mass that exhibited changed signal intensity at the same site, which suggested a neoplasm. Histological examination after the surgical resection revealed a mixed germ cell tumor.

  1. Modulation of Purkinje cell complex spike waveform by synchrony levels in the olivocerebellar system.

    Science.gov (United States)

    Lang, Eric J; Tang, Tianyu; Suh, Colleen Y; Xiao, Jianqiang; Kotsurovskyy, Yuriy; Blenkinsop, Timothy A; Marshall, Sarah P; Sugihara, Izumi

    2014-01-01

    Purkinje cells (PCs) generate complex spikes (CSs) when activated by the olivocerebellar system. Unlike most spikes, the CS waveform is highly variable, with the number, amplitude, and timing of the spikelets that comprise it varying with each occurrence. This variability suggests that CS waveform could be an important control parameter of olivocerebellar activity. The origin of this variation is not well known. Thus, we obtained extracellular recordings of CSs to investigate the possibility that the electrical coupling state of the inferior olive (IO) affects the CS waveform. Using multielectrode recordings from arrays of PCs we showed that the variance in the recording signal during the period when the spikelets occur is correlated with CS synchrony levels in local groups of PCs. The correlation was demonstrated under both ketamine and urethane, indicating that it is robust. Moreover, climbing fiber reflex evoked CSs showed an analogous positive correlation between spikelet-related variance and the number of cells that responded to a stimulus. Intra-IO injections of GABA-A receptor antagonists or the gap junction blocker carbenoxolone produced correlated changes in the variance and synchrony levels, indicating the presence of a causal relationship. Control experiments showed that changes in variance with synchrony were primarily due to changes in the CS waveform, as opposed to changes in the strength of field potentials from surrounding cells. Direct counts of spikelets showed that their number increased with synchronization of CS activity. In sum, these results provide evidence of a causal link between two of the distinguishing characteristics of the olivocerebellar system, its ability to generate synchronous activity and the waveform of the CS.

  2. The 5-HT7 receptor triggers cerebellar long-term synaptic depression via PKC-MAPK.

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    Lippiello, Pellegrino; Hoxha, Eriola; Speranza, Luisa; Volpicelli, Floriana; Ferraro, Angela; Leopoldo, Marcello; Lacivita, Enza; Perrone-Capano, Carla; Tempia, Filippo; Miniaci, Maria Concetta

    2016-02-01

    The 5-HT7 receptor (5-HT7R) mediates important physiological effects of serotonin, such as memory and emotion, and is emerging as a therapeutic target for the treatment of cognitive disorders and depression. Although previous studies have revealed an expression of 5-HT7R in cerebellum, particularly at Purkinje cells, its functional role and signaling mechanisms have never been described. Using patch-clamp recordings in cerebellar slices of adult mice, we investigated the effects of a selective 5-HT7R agonist, LP-211, on the main plastic site of the cerebellar cortex, the parallel fiber-Purkinje cell synapse. Here we show that 5-HT7R activation induces long-term depression of parallel fiber-Purkinje cell synapse via a postsynaptic mechanism that involves the PKC-MAPK signaling pathway. Moreover, a 5-HT7R antagonist abolished the expression of PF-LTD, produced by pairing parallel fiber stimulation with Purkinje cell depolarization; whereas, application of a 5-HT7R agonist impaired LTP induced by 1 Hz parallel fiber stimulation. Our results indicate for the first time that 5-HT7R exerts a fine regulation of cerebellar bidirectional synaptic plasticity that might be involved in cognitive processes and neuropsychiatric disorders involving the cerebellum.

  3. Type IV Collagen Controls the Axogenesis of Cerebellar Granule Cells by Regulating Basement Membrane Integrity in Zebrafish.

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    Takeuchi, Miki; Yamaguchi, Shingo; Yonemura, Shigenobu; Kakiguchi, Kisa; Sato, Yoshikatsu; Higashiyama, Tetsuya; Shimizu, Takashi; Hibi, Masahiko

    2015-10-01

    Granule cells (GCs) are the major glutamatergic neurons in the cerebellum, and GC axon formation is an initial step in establishing functional cerebellar circuits. In the zebrafish cerebellum, GCs can be classified into rostromedial and caudolateral groups, according to the locations of their somata in the corresponding cerebellar lobes. The axons of the GCs in the caudolateral lobes terminate on crest cells in the dorsal hindbrain, as well as forming en passant synapses with Purkinje cells in the cerebellum. In the zebrafish mutant shiomaneki, the caudolateral GCs extend aberrant axons. Positional cloning revealed that the shiomaneki (sio) gene locus encodes Col4a6, a subunit of type IV collagen, which, in a complex with Col4a5, is a basement membrane (BM) component. Both col4a5 and col4a6 mutants displayed similar abnormalities in the axogenesis of GCs and retinal ganglion cells (RGCs). Although type IV collagen is reported to control axon targeting by regulating the concentration gradient of an axonal guidance molecule Slit, Slit overexpression did not affect the GC axons. The structure of the BM surrounding the tectum and dorsal hindbrain was disorganized in the col4a5 and col4a6 mutants. Moreover, the abnormal axogenesis of the caudolateral GCs and the RGCs was coupled with aberrant BM structures in the type IV collagen mutants. The regrowth of GC axons after experimental ablation revealed that the original and newly formed axons displayed similar branching and extension abnormalities in the col4a6 mutants. These results collectively suggest that type IV collagen controls GC axon formation by regulating the integrity of the BM, which provides axons with the correct path to their targets.

  4. Type IV Collagen Controls the Axogenesis of Cerebellar Granule Cells by Regulating Basement Membrane Integrity in Zebrafish.

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    Miki Takeuchi

    2015-10-01

    Full Text Available Granule cells (GCs are the major glutamatergic neurons in the cerebellum, and GC axon formation is an initial step in establishing functional cerebellar circuits. In the zebrafish cerebellum, GCs can be classified into rostromedial and caudolateral groups, according to the locations of their somata in the corresponding cerebellar lobes. The axons of the GCs in the caudolateral lobes terminate on crest cells in the dorsal hindbrain, as well as forming en passant synapses with Purkinje cells in the cerebellum. In the zebrafish mutant shiomaneki, the caudolateral GCs extend aberrant axons. Positional cloning revealed that the shiomaneki (sio gene locus encodes Col4a6, a subunit of type IV collagen, which, in a complex with Col4a5, is a basement membrane (BM component. Both col4a5 and col4a6 mutants displayed similar abnormalities in the axogenesis of GCs and retinal ganglion cells (RGCs. Although type IV collagen is reported to control axon targeting by regulating the concentration gradient of an axonal guidance molecule Slit, Slit overexpression did not affect the GC axons. The structure of the BM surrounding the tectum and dorsal hindbrain was disorganized in the col4a5 and col4a6 mutants. Moreover, the abnormal axogenesis of the caudolateral GCs and the RGCs was coupled with aberrant BM structures in the type IV collagen mutants. The regrowth of GC axons after experimental ablation revealed that the original and newly formed axons displayed similar branching and extension abnormalities in the col4a6 mutants. These results collectively suggest that type IV collagen controls GC axon formation by regulating the integrity of the BM, which provides axons with the correct path to their targets.

  5. Modulation of p53 and met expression by Krüppel-like factor 8 regulates zebrafish cerebellar development.

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    Tsai, Ming-Yuan; Lu, Yu-Fen; Liu, Yu-Hsiu; Lien, Huang-Wei; Huang, Chang-Jen; Wu, Jen-Leih; Hwang, Sheng-Ping L

    2015-09-01

    Krüppel-like factor 8 (Klf8) is a zinc-finger transcription factor implicated in cell proliferation, and cancer cell survival and invasion; however, little is known about its role in normal embryonic development. Here, we show that Klf8 is required for normal cerebellar development in zebrafish embryos. Morpholino knockdown of klf8 resulted in abnormal cerebellar primordium morphology and the induction of p53 in the brain region at 24 hours post-fertilization (hpf). Both p53-dependent reduction of cell proliferation and augmentation of apoptosis were observed in the cerebellar anlage of 24 hpf-klf8 morphants. In klf8 morphants, expression of ptf1a in the ventricular zone was decreased from 48 to 72 hpf; on the other hand, expression of atohla in the upper rhombic lip was unaffected. Consistent with this finding, Purkinje cell development was perturbed and granule cell number was reduced in 72 hpf-klf8 morphants; co-injection of p53 MO(sp) or klf8 mRNA substantially rescued development of cerebellar Purkinje cells in klf8 morphants. Hepatocyte growth factor/Met signaling is known to regulate cerebellar development in zebrafish and mouse. We observed decreased met expression in the tectum and rhombomere 1 of 24 hpf-klf8 morphants, which was largely rescued by co-injection with klf8 mRNA. Moreover, co-injection of met mRNA substantially rescued formation of Purkinje cells in klf8 morphants at 72 hpf. Together, these results demonstrate that Klf8 modulates expression of p53 and met to maintain ptf1a-expressing neuronal progenitors, which are required for the appropriate development of cerebellar Purkinje and granule cells in zebrafish embryos.

  6. Contribution of cerebellar sensorimotor adaptation to hippocampal spatial memory.

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    Jean-Baptiste Passot

    Full Text Available Complementing its primary role in motor control, cerebellar learning has also a bottom-up influence on cognitive functions, where high-level representations build up from elementary sensorimotor memories. In this paper we examine the cerebellar contribution to both procedural and declarative components of spatial cognition. To do so, we model a functional interplay between the cerebellum and the hippocampal formation during goal-oriented navigation. We reinterpret and complete existing genetic behavioural observations by means of quantitative accounts that cross-link synaptic plasticity mechanisms, single cell and population coding properties, and behavioural responses. In contrast to earlier hypotheses positing only a purely procedural impact of cerebellar adaptation deficits, our results suggest a cerebellar involvement in high-level aspects of behaviour. In particular, we propose that cerebellar learning mechanisms may influence hippocampal place fields, by contributing to the path integration process. Our simulations predict differences in place-cell discharge properties between normal mice and L7-PKCI mutant mice lacking long-term depression at cerebellar parallel fibre-Purkinje cell synapses. On the behavioural level, these results suggest that, by influencing the accuracy of hippocampal spatial codes, cerebellar deficits may impact the exploration-exploitation balance during spatial navigation.

  7. Cerebellar and basal ganglion involvement in Langerhans cell histiocytosis

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    Saatci, I.; Baskan, O.; Haliloglu, M.; Aydingoz, U. [Department of Radiology, Hacettepe University Hospital, Sihhiye 06100, Ankara (Turkey)

    1999-06-01

    Langerhans cell histiocytosis (LCH) is a disease of unknown cause characterised by proliferation of histiocytic granulomas in tissues; the primary cerebral manifestation is diabetes insipidus caused by hypothalamic infiltration. We present a patient in whom, except for the absence of high signal on T 1 weighting in the posterior pituitary, consistent with central diabetes insipidus, MRI showed no evidence of hypothalamic involvement by histiocytosis, despite the long duration of the disease. However, there was bilateral, symmetrical involvement of the cerebellum and globus pallidus in addition to a calvarial lesion. High signal in the cerebellar white matter on T 2-weighted images may represent demyelination, gliosis and cell loss, as previously reported on pathologic examination. (orig.) With 5 figs., 22 refs.

  8. Mapping of the SCA23 locus involved in autosomal dominant cerebellar ataxia to chromosome region 20p13-12.3

    NARCIS (Netherlands)

    Verbeek, D S; van de Warrenburg, B P; Wesseling, P; Pearson, P L; Kremer, H P; Sinke, R J

    2004-01-01

    We report upon a Dutch autosomal dominant cerebellar ataxia (ADCA) family, clinically characterized by a late-onset (>40 years), slowly progressive, isolated spinocerebellar ataxia (SCA). Neuropathological examination in one affected subject showed neuronal loss in the Purkinje cell layer, dentate n

  9. The Phospholipase D2 Knock Out Mouse Has Ectopic Purkinje Cells and Suffers from Early Adult-Onset Anosmia

    Science.gov (United States)

    Zhang, Qifeng; Smethurst, Elizabeth; Segonds-Pichon, Anne; Schrewe, Heinrich; Wakelam, Michael J. O.

    2016-01-01

    Phospholipase D2 (PLD2) is an enzyme that produces phosphatidic acid (PA), a lipid messenger molecule involved in a number of cellular events including, through its membrane curvature properties, endocytosis. The PLD2 knock out (PLD2KO) mouse has been previously reported to be protected from insult in a model of Alzheimer's disease. We have further analysed a PLD2KO mouse using mass spectrophotometry of its lipids and found significant differences in PA species throughout its brain. We have examined the expression pattern of PLD2 which allowed us to define which region of the brain to analyse for defect, notably PLD2 was not detected in glial-rich regions. The expression pattern lead us to specifically examine the mitral cells of olfactory bulbs, the Cornus Amonis (CA) regions of the hippocampus and the Purkinje cells of the cerebellum. We find that the change to longer PA species correlates with subtle architectural defect in the cerebellum, exemplified by ectopic Purkinje cells and an adult-onset deficit of olfaction. These observations draw parallels to defects in the reelin heterozygote as well as the effect of high fat diet on olfaction. PMID:27658289

  10. Establishment of Gal4 transgenic zebrafish lines for analysis of development of cerebellar neural circuitry.

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    Takeuchi, Miki; Matsuda, Koji; Yamaguchi, Shingo; Asakawa, Kazuhide; Miyasaka, Nobuhiko; Lal, Pradeep; Yoshihara, Yoshihiro; Koga, Akihiko; Kawakami, Koichi; Shimizu, Takashi; Hibi, Masahiko

    2015-01-01

    The cerebellum is involved in some forms of motor coordination and motor learning. Here we isolated transgenic (Tg) zebrafish lines that express a modified version of Gal4-VP16 (GFF) in the cerebellar neural circuits: granule, Purkinje, or eurydendroid cells, Bergmann glia, or the neurons in the inferior olive nuclei (IO) which send climbing fibers to Purkinje cells, with the transposon Tol2 system. By combining GFF lines with Tg lines carrying a reporter gene located downstream of Gal4 binding sequences (upstream activating sequence: UAS), we investigated the anatomy and developmental processes of the cerebellar neural circuitry. Combining an IO-specific Gal4 line with a UAS reporter line expressing the photoconvertible fluorescent protein Kaede demonstrated the contralateral projections of climbing fibers. Combining a granule cell-specific Gal4 line with a UAS reporter line expressing wheat germ agglutinin (WGA) confirmed direct and/or indirect connections of granule cells with Purkinje cells, eurydendroid cells, and IO neurons in zebrafish. Time-lapse analysis of a granule cell-specific Gal4 line revealed initial random movements and ventral migration of granule cell nuclei. Transgenesis of a reporter gene with another transposon Tol1 system visualized neuronal structure at a single cell resolution. Our findings indicate the usefulness of these zebrafish Gal4 Tg lines for studying the development and function of cerebellar neural circuits.

  11. Segmental identity and cerebellar granule cell induction in rhombomere 1

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    Bell Esther

    2004-06-01

    Full Text Available Abstract Background Cerebellar granule cell precursors are specifically generated within the hindbrain segment, rhombomere 1, which is bounded rostrally by the midbrain/hindbrain isthmus and caudally by the boundary of the Hoxa2 expression domain. While graded signals from the isthmus have a demonstrable patterning role within this region, the significance of segmental identity for neuronal specification within rhombomere 1 is unexplored. We examined the response of granule cell precursors to the overexpression of Hoxa2, which normally determines patterns of development specific to the hindbrain. How much does the development of the cerebellum, a midbrain/hindbrain structure, reflect its neuromeric origin as a hindbrain segment? Results We show that a Gbx2-positive, Otx2-/Hoxa2-negative territory corresponding to rhombomere 1 forms prior to an identifiable isthmic organiser. Early global overexpression of Hoxa2 at embryonic day 0 has no effect on the expression of isthmic signalling molecules or the allocation of rhombomere 1 territory, but selectively results in the loss of granule cell markers at embryonic day 6 and the depletion of cell bodies from the external granule cell layer. By comparison the trochlear nucleus and locus coeruleus form normally in ventral rhombomere 1 under these conditions. Microsurgery, coupled with electroporation, to target Hoxa2 overexpression to rhombic lip precursors, reveals a profound, autonomous respecification of migration. Rhombic lip derivatives, normally destined to occupy the external granule cell layer, violate the cerebellar boundary to form a ventrolateral nucleus in a position comparable to that occupied by rhombic lip derived neurons in rhombomere 2. Conclusions Different overexpression strategies reveal that the recognition of migration cues by granule cell precursors is dependent on their identity as rhombomere 1 derivatives. Segmental patterning cues operate autonomously within the rhombic lip

  12. Optogenetic mapping of cerebellar inhibitory circuitry reveals spatially biased coordination of interneurons via electrical synapses.

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    Kim, Jinsook; Lee, Soojung; Tsuda, Sachiko; Zhang, Xuying; Asrican, Brent; Gloss, Bernd; Feng, Guoping; Augustine, George J

    2014-06-12

    We used high-speed optogenetic mapping technology to examine the spatial organization of local inhibitory circuits formed by cerebellar interneurons. Transgenic mice expressing channelrhodopsin-2 exclusively in molecular layer interneurons allowed us to focally photostimulate these neurons, while measuring resulting responses in postsynaptic Purkinje cells. This approach revealed that interneurons converge upon Purkinje cells over a broad area and that at least seven interneurons form functional synapses with a single Purkinje cell. The number of converging interneurons was reduced by treatment with gap junction blockers, revealing that electrical synapses between interneurons contribute substantially to the spatial convergence. Remarkably, gap junction blockers affected convergence in sagittal slices, but not in coronal slices, indicating a sagittal bias in electrical coupling between interneurons. We conclude that electrical synapse networks spatially coordinate interneurons in the cerebellum and may also serve this function in other brain regions.

  13. Stochastic differential equation model for cerebellar granule cell excitability.

    Science.gov (United States)

    Saarinen, Antti; Linne, Marja-Leena; Yli-Harja, Olli

    2008-02-29

    Neurons in the brain express intrinsic dynamic behavior which is known to be stochastic in nature. A crucial question in building models of neuronal excitability is how to be able to mimic the dynamic behavior of the biological counterpart accurately and how to perform simulations in the fastest possible way. The well-established Hodgkin-Huxley formalism has formed to a large extent the basis for building biophysically and anatomically detailed models of neurons. However, the deterministic Hodgkin-Huxley formalism does not take into account the stochastic behavior of voltage-dependent ion channels. Ion channel stochasticity is shown to be important in adjusting the transmembrane voltage dynamics at or close to the threshold of action potential firing, at the very least in small neurons. In order to achieve a better understanding of the dynamic behavior of a neuron, a new modeling and simulation approach based on stochastic differential equations and Brownian motion is developed. The basis of the work is a deterministic one-compartmental multi-conductance model of the cerebellar granule cell. This model includes six different types of voltage-dependent conductances described by Hodgkin-Huxley formalism and simple calcium dynamics. A new model for the granule cell is developed by incorporating stochasticity inherently present in the ion channel function into the gating variables of conductances. With the new stochastic model, the irregular electrophysiological activity of an in vitro granule cell is reproduced accurately, with the same parameter values for which the membrane potential of the original deterministic model exhibits regular behavior. The irregular electrophysiological activity includes experimentally observed random subthreshold oscillations, occasional spontaneous spikes, and clusters of action potentials. As a conclusion, the new stochastic differential equation model of the cerebellar granule cell excitability is found to expand the range of dynamics

  14. Ataxia with loss of Purkinje cells in a mouse model for Refsum disease.

    NARCIS (Netherlands)

    Ferdinandusse, S.; Zomer, A.W.M.; Komen, J.C.; van den Brink, C.; Thanos, M.; Hamers, F.P.T.; Wanders, R.J.A.T.; van der Saag, P.T.; Poll-The, B.T.; Brites, P.

    2008-01-01

    Refsum disease is caused by a deficiency of phytanoyl-CoA hydroxylase (PHYH), the first enzyme of the peroxisomal alpha-oxidation system, resulting in the accumulation of the branched-chain fatty acid phytanic acid. The main clinical symptoms are polyneuropathy, cerebellar ataxia, and retinitis pigm

  15. Evolving Models of Pavlovian Conditioning: Cerebellar Cortical Dynamics in Awake Behaving Mice

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    Michiel M. ten Brinke

    2015-12-01

    Full Text Available Three decades of electrophysiological research on cerebellar cortical activity underlying Pavlovian conditioning have expanded our understanding of motor learning in the brain. Purkinje cell simple spike suppression is considered to be crucial in the expression of conditional blink responses (CRs. However, trial-by-trial quantification of this link in awake behaving animals is lacking, and current hypotheses regarding the underlying plasticity mechanisms have diverged from the classical parallel fiber one to the Purkinje cell synapse LTD hypothesis. Here, we establish that acquired simple spike suppression, acquired conditioned stimulus (CS-related complex spike responses, and molecular layer interneuron (MLI activity predict the expression of CRs on a trial-by-trial basis using awake behaving mice. Additionally, we show that two independent transgenic mouse mutants with impaired MLI function exhibit motor learning deficits. Our findings suggest multiple cerebellar cortical plasticity mechanisms underlying simple spike suppression, and they implicate the broader involvement of the olivocerebellar module within the interstimulus interval.

  16. Cerebellar Fastigial Nucleus Electrical Stimulation Alleviates Depressive-Like Behaviors in Post-Stroke Depression Rat Model and Potential Mechanisms

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    Lei Zhang

    2017-03-01

    Full Text Available Objective: To identify the molecular mechanism of post-stroke depression (PSD, and observe the therapeutic effects of cerebellar fastigial nucleus electrical stimulation (FNS on the behaviors and regional cerebral blood flow (rCBF in a PSD rat model. Methods: Healthy SD rats were randomly divided into four groups (sham, stroke, post-stroke depress and FNS group. Sham group (n = 6 underwent sham operation. The other three groups (n = 6*3 underwent MCAO. Rats were examined twice a week in open filed test. Moreover, neuroprotective effect on cerebellar Purkinje cells and expression of cytokines in hippocampal tissue were examined. Results: The PSD group showed a significant weight loss, decreased consumption of sucrose water, reduced rearing and locomotor activities. The FNS significantly alleviates the body weight loss and sucrose preference, locomotor and rearing activities. The bilateral rCBF was also restored after FNS treatment. Moreover, FNS improved the neuroprotection via suppressing apoptosis of cerebellar Purkinje cells. And the inflammatory cytokines mRNA level in hippocampus was significantly decreased. Conclusion: FNS treatment alleviates depressive-like behaviors and rCBF in PSD rats model, which could be attributed to its ability to protect cerebellar Purkinje cells and decrease the mRNA level of inflammatory cytokines.

  17. Long lasting cerebellar alterations after perinatal asphyxia in rats.

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    Campanille, Verónica; Saraceno, G Ezequiel; Rivière, Stéphanie; Logica, Tamara; Kölliker, Rodolfo; Capani, Francisco; Castilla, Rocío

    2015-07-01

    The developing brain may be particularly vulnerable to injury before, at and after birth. Among possible insults, hypoxia suffered as a consequence of perinatal asphyxia (PA) exhibits the highest incidence levels and the cerebellar circuitry appears to be particularly susceptible, as the cellular makeup and the quantity of inputs change quickly during days and weeks following birth. In this work, we have used a murine model to induce severe global PA in rats at the time of birth. Short-term cerebellar alterations within this PA model have been previously reported but whether such alterations remain in adulthood has not been conclusively determined yet. For this reason, and given the crucial cerebellar role in determining connectivity patterns in the brain, the aim of our work is to unveil long-term cerebellum histomorphology following a PA insult. Morphological and cytological neuronal changes and glial reaction in the cerebellar cortex were analyzed at postnatal 120 (P120) following injury performed at birth. As compared to control, PA animals exhibited: (1) an increase in molecular and granular thickness, both presenting lower cellular density; (2) a disarrayed Purkinje cell layer presenting a higher number of anomalous calbindin-stained cells. (3) focal swelling and marked fragmentation of microtubule-associated protein 2 (MAP-2) in Purkinje cell dendrites and, (4) an increase in glial fibrillary acidic protein (GFAP) expression in Bergmann cells and the granular layer. In conclusion, we demonstrate that PA produces long-term damage in cellular histomorphology in rat cerebellar cortex which could be involved in the pathogenesis of cognitive deficits observed in both animals and humans.

  18. The Effect of Salvia Rhytidea Extract on the Number of Cells of Different Layers of Cerebellar Cortex Following Ischemia Reperfusion in Rats

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    M Farahmand

    2016-09-01

    Full Text Available Background & aim: Salvia has anti-oxidant oxygen free radicals which are generated during the interruption and reestablishment of ischemia reperfusion.  The aim of study was to investigate the effect of Salvia Rhytidea extract on the number of cells of different layers of cerebellar cortex following ischemia reperfusion in rats. Methods: In the present experimental study, 35 adult male rats were randomly divided into 7 groups of 5: Group 1 (control-: Sampling without ischemia. Group 2 (control +: Cerebellar ischemia with administration of normal saline. Group 3(sham: Manipulation without ischemia with normal saline administration. Group 4   received (3.2 mg/kg aqueous and alcoholic Salvia extract 2 hours after ischemia. Group 5 received 50 mg/kg silymarin drug, 2 hours after ischemia. Group 6 received 3.2 mg/kg aqueous and alcoholic Salvia extract 72, 48, 24 and 0 h before ischemia and group 7 received silymarin drug (50 mg/kg, 0, 24, 48, and 72, hrs. before ischemia. 24 hrs. following reperfusion, the rats were euthanized and samples of the cerebellum were obtained. By using routine histological technique, the sections were stained by H&E. The measurement of cell count in cerebellar cortex were accomplished. Data were evaluated with One-Way ANOVA and Tukey diagnostic tests. Results: A significant decrease was observed in the number of neural cells in granular layer in the non-treated ischemia group and in the groups which received Salvia extract and silymarin, two hours after the ischemia (p< 0.05. No significant decrease was observed in the number of cells of this layer in the groups which received salvia extract before ischemia. But regarding the cell number of molecular and purkinje layers in above groups, no significant difference was observed compared to the control group (P˃0.05. However, no significant differences was seen in the number of cells layers compared to the control group (P˃0.05. Conclusion: Finally, administration of

  19. GDNF-induced cerebellar toxicity: A brief review.

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    Luz, Matthias; Mohr, Erich; Fibiger, H Christian

    2016-01-01

    Recombinant-methionyl human glial cell line-derived neurotrophic factor (GDNF) is known for its neurorestorative and neuroprotective effects in rodent and primate models of Parkinson's disease (PD). When administered locally into the putamen of Parkinsonian subjects, early clinical studies showed its potential promise as a disease-modifying agent. However, the development of GDNF for the treatment of PD has been significantly clouded by findings of cerebellar toxicity after continuous intraputamenal high-dose administration in a 6-month treatment/3-month recovery toxicology study in rhesus monkeys. Specifically, multifocal cerebellar Purkinje cell loss affecting 1-21% of the cerebellar cortex was observed in 4 of 15 (26.7%; 95% confidence interval [CI]: 10.5-52.4%) animals treated at the highest dose level tested (3000μg/month). No cerebellar toxicity was observed at lower doses (450 and 900μg/month) in the same study, or at similar or higher doses (up to 10,000μg/month) in subchronic or chronic toxicology studies testing intermittent intracerebroventricular administration. While seemingly associated with the use of GDNF, the pathogenesis of the cerebellar lesions has not been fully understood to date. This review integrates available information to evaluate potential pathogenic mechanisms and provide a consolidated assessment of the findings. While other explanations are considered, the existing evidence is most consistent with the hypothesis that leakage of GDNF into cerebrospinal fluid during chronic infusions into the putamen down-regulates GDNF receptors on Purkinje cells, and that subsequent acute withdrawal of GDNF generates the observed lesions. The implications of these findings for clinical studies with GDNF are discussed.

  20. Cerebellar stem cells do not produce neurons and astrocytes in adult mouse

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    Su, Xin; Guan, Wuqiang; Yu, Yong-Chun; Fu, Yinghui, E-mail: fuyh@fudan.edu.cn

    2014-07-18

    Highlights: • No new neurons and astrocytes are generated in adult mouse cerebellum. • Very few mash1{sup +} or nestin{sup +} stem cells exist, and most of them are quiescent. • Cell proliferation rate is diversified among cerebellar regions and decreases over time. - Abstract: Although previous studies implied that cerebellar stem cells exist in some adult mammals, little is known about whether these stem cells can produce new neurons and astrocytes. In this study by bromodeoxyuridine (BrdU) intraperitoneal (i.p.) injection, we found that there are abundant BrdU{sup +} cells in adult mouse cerebellum, and their quantity and density decreases significantly over time. We also found cell proliferation rate is diversified in different cerebellar regions. Among these BrdU{sup +} cells, very few are mash1{sup +} or nestin{sup +} stem cells, and the vast majority of cerebellar stem cells are quiescent. Data obtained by in vivo retrovirus injection indicate that stem cells do not produce neurons and astrocytes in adult mouse cerebellum. Instead, some cells labeled by retrovirus are Iba1{sup +} microglia. These results indicate that very few stem cells exist in adult mouse cerebellum, and none of these stem cells contribute to neurogenesis and astrogenesis under physiological condition.

  1. Acute ethanol exposure inhibits silencing of cerebellar Golgi cell firing induced by granule cell axon input

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    Paolo eBotta

    2014-02-01

    Full Text Available Golgi cells (GoCs are specialized interneurons that provide inhibitory input to granule cells in the cerebellar cortex. GoCs are pacemaker neurons that spontaneously fire action potentials, triggering spontaneous inhibitory postsynaptic currents in granule cells and also contributing to the generation tonic GABAA receptor-mediated currents in granule cells. In turn, granule cell axons provide feedback glutamatergic input to GoCs. It has been shown that high frequency stimulation of granule cell axons induces a transient pause in GoC firing in a type 2-metabotropic glutamate receptor (mGluR2-dependent manner. Here, we investigated the effect ethanol on the pause of GoC firing induced by high frequency stimulation of granule cell axons. GoC electrophysiological recordings were performed in parasagittal cerebellar vermis slices from postnatal day 23 to 26 rats. Loose-patch cell-attached recordings revealed that ethanol (40 mM reversibly decreases the pause duration. An antagonist of mGluR2 reduced the pause duration but did not affect the effect of ethanol. Whole-cell voltage-clamp recordings showed that currents evoked by an mGluR2 agonist were not significantly affected by ethanol. Perforated-patch experiments in which hyperpolarizing and depolarizing currents were injected into GoCs demonstrated that there is an inverse relationship between spontaneous firing and pause duration. Slight inhibition of the Na+/K+ pump mimicked the effect of ethanol on pause duration. In conclusion, ethanol reduces the granule cell axon-mediated feedback mechanism by reducing the input responsiveness of GoCs. This would result in a transient increase of GABAA receptor-mediated inhibition of granule cells, limiting information flow at the input stage of the cerebellar cortex.

  2. Effects of ethanol and NAP on cerebellar expression of the neural cell adhesion molecule L1.

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    Devon M Fitzgerald

    Full Text Available The neural cell adhesion molecule L1 is critical for brain development and plays a role in learning and memory in the adult. Ethanol inhibits L1-mediated cell adhesion and neurite outgrowth in cerebellar granule neurons (CGNs, and these actions might underlie the cerebellar dysmorphology of fetal alcohol spectrum disorders. The peptide NAP potently blocks ethanol inhibition of L1 adhesion and prevents ethanol teratogenesis. We used quantitative RT-PCR and Western blotting of extracts of cerebellar slices, CGNs, and astrocytes from postnatal day 7 (PD7 rats to investigate whether ethanol and NAP act in part by regulating the expression of L1. Treatment of cerebellar slices with 20 mM ethanol, 10(-12 M NAP, or both for 4 hours, 24 hours, and 10 days did not significantly affect L1 mRNA and protein levels. Similar treatment for 4 or 24 hours did not regulate L1 expression in primary cultures of CGNs and astrocytes, the predominant cerebellar cell types. Because ethanol also damages the adult cerebellum, we studied the effects of chronic ethanol exposure in adult rats. One year of binge drinking did not alter L1 gene and protein expression in extracts from whole cerebellum. Thus, ethanol does not alter L1 expression in the developing or adult cerebellum; more likely, ethanol disrupts L1 function by modifying its conformation and signaling. Likewise, NAP antagonizes the actions of ethanol without altering L1 expression.

  3. Development of "Pinceaux" formations and dendritic translocation of climbing fibers during the acquisition of the balance between glutamatergic and gamma-aminobutyric acidergic inputs in developing Purkinje cells.

    Science.gov (United States)

    Sotelo, Constantino

    2008-01-10

    The acquisition of the dynamic balance between excitation and inhibition in developing Purkinje cells, necessary for their proper function, is analyzed. Newborn (P0) mouse cerebellum contains glutamatergic (VGLUT2-IR) and gamma-aminobutyric acid (GABA)-ergic (VIAAT-IR) axons. The former prevail and belong to climbing fibers, whereas the latter neither colabel with calbindin-expressing fibers nor belong to axons of the cortical GABAergic interneurons. During the first postnatal week, VIAAT-IR axons in the Purkinje cell neighborhood remains very low, and the first synapses with basket fibers are formed at P7, when climbing fibers have already established dense pericellular nets. The descending basket fibers reach the Purkinje cell axon initial segment by P9, immediately establishing axoaxonic synapses. The pinceaux appear as primitive vortex-like arrangements by P12, and by P20 interbasket fiber septate-like junctions, typical of fully mature pinceaux, are still missing. The climbing fiber's somatodendritic translocation occurs later than expected, after the regression of the multiple innervation, and follows the ascending collaterals of the basket axons, which are apparently the optimal substrate for the proper subcellular targeting of the climbing fibers. These results emphasize that chemical transmission in the axon initial segment precedes the electrical inhibition generated by field effects. In addition, GABAergic Purkinje cells, as opposed to glutamatergic projection neurons in other cortical structures, do not begin to receive their excitation to inhibition balance until the end of the first postnatal week, despite the early presence of potentially functional GABAergic axons that possess the required vesicular transport system.

  4. N-methyl-D-aspartate promotes the survival of cerebellar granule cells in culture

    DEFF Research Database (Denmark)

    Balázs, R; Jørgensen, Ole Steen; Hack, N

    1988-01-01

    Our previous studies on the survival-promoting influence of elevated concentrations of extracellular K+ ([K+]e) on cultured cerebellar granule cells led to the proposal that depolarization in vitro mimics the effect of the earliest afferent inputs received by the granule cells in vivo. This, in t...

  5. Effects of low-level x-irradiation on cat cerebella at different postnatal intervals. II. Changes in Purkinje cell morphology

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, W.J.; Stromberg, M.W.

    1977-01-01

    The whole-head of infant kittens was irradiated with fractionated doses of 150 R and 200 R at different postnatal intervals. Experimental age conditions consisted of an irradiated newborn, 1-week, 2-week, 3-week, and a 4-week age condition while the age of sacrifice remained constant at 70 days. The molecular layer thickness was reduced by 47 percent in the newborn, 40 percent in the 1-week group, 17 percent in the 2-week group, 19 percent in the 3-week group and by 9 percent in the 4-week group. An evaluation of Golgi impregnated material revealed that the dendritic arborizations of Purkinje cells were consistently reduced the earlier the age at which radiation was begun. A reduction in spiny branchlets was seen in all of the experimental conditions. Climbing fibers were found to conform to the abnormal dendritic arborizations of the Purkinje cells, and were reduced in complexity in the early radiation treatment groups. This suggested that climbing fibers had no influence upon the dendritic growth pattern, but instead were under the influence of the Purkinje cell dendritic growth.

  6. Cerebellar deficits and hyperactivity in mice lacking Smad4.

    Science.gov (United States)

    Zhou, Yong-Xing; Zhao, Mingrui; Li, Dan; Shimazu, Kazuhiro; Sakata, Kazuko; Deng, Chu-Xia; Lu, Bai

    2003-10-24

    Smad4 is a central mediator of TGF-beta signals, which are known to play essential roles in many biological processes. Using a Cre-loxP approach to overcome early embryonic lethality, we have studied functions of TGF-beta/Smad4 signals in the central nervous system (CNS). No obvious deficits were detected in mice carrying the targeted disruption of Smad4 in the CNS. The overall morphology of the hippocampus appeared normal. There was no change in the proliferation of neuronal precursor cells, nor in several forms of synaptic plasticity. In contrast, deletion of Smad4 resulted in a marked decrease in the number of cerebellar Purkinje cells and parvalbumin-positive interneurons. Accompanied by the abnormality in the cerebellum, mutant mice also exhibited significantly increased vertical activity. Thus, our study reveals an unexpected role for Smad4 in cerebellar development and in the control of motor function.

  7. Adaptive control of 2-wheeled balancing robot by cerebellar neuronal network model.

    Science.gov (United States)

    Tanaka, Yoshiyuki; Ohata, Yohei; Kawamoto, Tomohiro; Hirata, Yutaka

    2010-01-01

    A new adaptive motor controller was constructed, and tested on the control of a 2-wheeled balancing robot in simulation and real world. The controller consists of a feedback (PD) controller and a cerebellar neuronal network model. The structure of the cerebellar model was configured based upon known anatomical neuronal connection in the cerebellar cortex. Namely it consists of 120 granular (Gr) cells, 1 Golgi cell, 6 basket/stellate cells, and 1 Purkinje (Pk) cell. Each cell is described by a typical artificial neuron model that outputs a weighted sum of inputs after a sigmoidal nonlinear transformation. The 2 components of the proposed controller work in parallel, in a way that the cerebellar model adaptively modifies the synaptic weights between Gr and Pk as in the real cerebellum to minimize the output of the PD controller. We demonstrate that the proposed controller successfully controls a 2-wheeled balancing robot, and the cerebellar model rapidly takes over the PD controller in simulation. We also show that an abrupt load change on the robot, which the PD controller alone cannot compensate for, can be adaptively compensated by the cerebellar model. We further confirmed that the proposed controller can be applied to the control of the robot in real world.

  8. A computational study of synaptic mechanisms of partial memory transfer in cerebellar vestibulo-ocular-reflex learning.

    Science.gov (United States)

    Masuda, Naoki; Amari, Shun-ichi

    2008-04-01

    There is a debate regarding whether motor memory is stored in the cerebellar cortex, or the cerebellar nuclei, or both. Memory may be acquired in the cortex and then be transferred to the cerebellar nuclei. Based on a dynamical system modeling with a minimal set of variables, we theoretically investigated possible mechanisms of memory transfer and consolidation in the context of vestibulo-ocular reflex learning. We tested different plasticity rules for synapses in the cerebellar nuclei and took robustness of behavior against parameter variation as the criterion of plausibility of a model variant. In the most plausible scenarios, mossy-fiber nucleus-neuron synapses or Purkinje-cell nucleus-neuron synapses are plastic on a slow time scale and store permanent memory, whose content is passed from the cerebellar cortex storing transient memory. In these scenarios, synaptic strengths are potentiated when the mossy-fiber afferents to the nuclei are active during a pause in Purkinje-cell activities. Furthermore, assuming that mossy fibers create a limited variety of signals compared to parallel fibers, our model shows partial memory transfer from the cortex to the nuclei.

  9. Nucleolar disruption and cajal body disassembly are nuclear hallmarks of DNA damage-induced neurodegeneration in purkinje cells.

    Science.gov (United States)

    Baltanás, Fernando C; Casafont, Iñigo; Weruaga, Eduardo; Alonso, José R; Berciano, María T; Lafarga, Miguel

    2011-07-01

    The Purkinje cell (PC) degeneration (pcd) phenotype results from mutation in nna1 gene and is associated with the degeneration and death of PCs during the postnatal life. Although the pcd mutation is a model of the ataxic mouse, it shares clinical and pathological characteristics of inherited human spinocerebellar ataxias. PC degeneration in pcd mice provides a useful neuronal system to study nuclear mechanisms involved in DNA damage-dependent neurodegeneration, particularly the contribution of nucleoli and Cajal bodies (CBs). Both nuclear structures are engaged in housekeeping functions for neuronal survival, the biogenesis of ribosomes and the maturation of snRNPs and snoRNPs required for pre-mRNA and pre-rRNA processing, respectively. In this study, we use ultrastructural analysis, in situ transcription assay and molecular markers for DNA damage, nucleoli and CB components to demonstrate that PC degeneration involves the progressive accumulation of nuclear DNA damage associated with disruption of nucleoli and CBs, disassembly of polyribosomes into monoribosomes, ribophagy and shut down of nucleolar and extranucleolar transcription. Microarray analysis reveals that four genes encoding repressors of nucleolar rRNA synthesis (p53, Rb, PTEN and SNF2) are upregulated in the cerebellum of pcd mice. Collectively, these data support that nucleolar and CB alterations are hallmarks of DNA damage-induced neurodegeneration.

  10. First report of cerebellar abiotrophy in an Arabian foal from Argentina

    Directory of Open Access Journals (Sweden)

    S.A. Sadaba

    2016-12-01

    Full Text Available Evidence of cerebellar abiotrophy (CA was found in a six-month-old Arabian filly with signs of incoordination, head tremor, wobbling, loss of balance and falling over, consistent with a cerebellar lesion. Normal hematology profile blood test and cerebrospinal fluid analysis excluded infectious encephalitis, and serological testing for Sarcocystis neurona was negative. The filly was euthanized. Postmortem X-ray radiography of the cervical cephalic region identified not abnormalities, discounting spinal trauma. The histopathological analysis of serial transverse cerebellar sections by electron microscopy revealed morphological characteristics of apoptotic cells with pyknotic nuclei and degenerate mitochondria, cytoplasmic condensation and areas with absence of Purkinje cells, matching with CA histopathological characteristics. The indirect DNA test for CA was positive in the filly, and DNA test confirmed the CA carrier state in the parents and the recessive inheritance of the disease. To our knowledge this is the first report of a CA case in Argentina.

  11. First report of cerebellar abiotrophy in an Arabian foal from Argentina

    Science.gov (United States)

    Sadaba, S.A.; Madariaga, G.J.; Botto, C.M. Corbi; Carino, M.H.; Zappa, M.E.; García, P. Peral; Olguín, S.A.; Massone, A.; Díaz, S.

    2016-01-01

    Evidence of cerebellar abiotrophy (CA) was found in a six-month-old Arabian filly with signs of incoordination, head tremor, wobbling, loss of balance and falling over, consistent with a cerebellar lesion. Normal hematology profile blood test and cerebrospinal fluid analysis excluded infectious encephalitis, and serological testing for Sarcocystis neurona was negative. The filly was euthanized. Postmortem X-ray radiography of the cervical cephalic region identified not abnormalities, discounting spinal trauma. The histopathological analysis of serial transverse cerebellar sections by electron microscopy revealed morphological characteristics of apoptotic cells with pyknotic nuclei and degenerate mitochondria, cytoplasmic condensation and areas with absence of Purkinje cells, matching with CA histopathological characteristics. The indirect DNA test for CA was positive in the filly, and DNA test confirmed the CA carrier state in the parents and the recessive inheritance of the disease. To our knowledge this is the first report of a CA case in Argentina. PMID:28116251

  12. Hyperpolarization induces a long-term increase in the spontaneous firing rate of cerebellar Golgi cells

    OpenAIRE

    Hull, Court; Chu, YunXiang; Thanawala, Monica; Regehr, Wade G.

    2013-01-01

    Golgi cells (GoCs) are inhibitory interneurons that influence the cerebellar cortical response to sensory input by regulating the excitability of the granule cell layer. While GoC inhibition is essential for normal motor coordination, little is known about the circuit dynamics that govern the activity of these cells. In particular, while GoC spontaneous spiking influences the extent of inhibition and gain throughout the granule cell layer, it is not known whether this spontaneous activity can...

  13. Integrated plasticity at inhibitory and excitatory synapses in the cerebellar circuit

    Directory of Open Access Journals (Sweden)

    Lisa eMapelli

    2015-05-01

    Full Text Available The way long-term potentiation (LTP and depression (LTD are integrated within the different synapses of brain neuronal circuits is poorly understood. In order to progress beyond the identification of specific molecular mechanisms, a system in which multiple forms of plasticity can be correlated with large-scale neural processing is required. In this paper we take as an example the cerebellar network , in which extensive investigations have revealed LTP and LTD at several excitatory and inhibitory synapses. Cerebellar LTP and LTD occur in all three main cerebellar subcircuits (granular layer, molecular layer, deep cerebellar nuclei and correspondingly regulate the function of their three main neurons: granule cells (GrCs, Purkinje cells (PCs and deep cerebellar nuclear (DCN cells. All these neurons, in addition to be excited, are reached by feed-forward and feed-back inhibitory connections, in which LTP and LTD may either operate synergistically or homeostatically in order to control information flow through the circuit. Although the investigation of individual synaptic plasticities in vitro is essential to prove their existence and mechanisms, it is insufficient to generate a coherent view of their impact on network functioning in vivo. Recent computational models and cell-specific genetic mutations in mice are shedding light on how plasticity at multiple excitatory and inhibitory synapses might regulate neuronal activities in the cerebellar circuit and contribute to learning and memory and behavioral control.

  14. Integrated plasticity at inhibitory and excitatory synapses in the cerebellar circuit.

    Science.gov (United States)

    Mapelli, Lisa; Pagani, Martina; Garrido, Jesus A; D'Angelo, Egidio

    2015-01-01

    The way long-term potentiation (LTP) and depression (LTD) are integrated within the different synapses of brain neuronal circuits is poorly understood. In order to progress beyond the identification of specific molecular mechanisms, a system in which multiple forms of plasticity can be correlated with large-scale neural processing is required. In this paper we take as an example the cerebellar network, in which extensive investigations have revealed LTP and LTD at several excitatory and inhibitory synapses. Cerebellar LTP and LTD occur in all three main cerebellar subcircuits (granular layer, molecular layer, deep cerebellar nuclei) and correspondingly regulate the function of their three main neurons: granule cells (GrCs), Purkinje cells (PCs) and deep cerebellar nuclear (DCN) cells. All these neurons, in addition to be excited, are reached by feed-forward and feed-back inhibitory connections, in which LTP and LTD may either operate synergistically or homeostatically in order to control information flow through the circuit. Although the investigation of individual synaptic plasticities in vitro is essential to prove their existence and mechanisms, it is insufficient to generate a coherent view of their impact on network functioning in vivo. Recent computational models and cell-specific genetic mutations in mice are shedding light on how plasticity at multiple excitatory and inhibitory synapses might regulate neuronal activities in the cerebellar circuit and contribute to learning and memory and behavioral control.

  15. Light and electron microscopic localization of GABAA-receptors on cultured cerebellar granule cells and astrocytes using immunohistochemical techniques

    DEFF Research Database (Denmark)

    Hansen, G H; Hösli, E; Belhage, B;

    1991-01-01

    GABAA-receptors were localized in explant cultures of rat cerebellum and in dissociated primary cultures of rat cerebellar granule cells and rat cerebellar astrocytes using the monoclonal antibody bd-17 directed against the beta-subunit of the GABAA/benzodiazepine/chloride channel complex. At the...

  16. Weaver mutant mouse cerebellar granule cells respond normally to chronic depolarization

    DEFF Research Database (Denmark)

    Bjerregaard, Annette; Mogensen, Helle Smidt; Hack, N;

    1997-01-01

    We studied the effects of chronic K(+)-induced membrane depolarization and treatment with N-methyl-D-aspartate (NMDA) on cerebellar granule cells (CGCs) from weaver mutant mice and non-weaver litter-mates. The weaver mutation is a Gly-to-Ser substitution in a conserved region of the Girk2 G prote...

  17. The cellular state determines the effect of melatonin on the survival of mixed cerebellar cell culture.

    Directory of Open Access Journals (Sweden)

    Daiane Gil Franco

    Full Text Available The constitutive activation of nuclear factor-κB (NF-κB, a key transcription factor involved in neuroinflammation, is essential for the survival of neurons in situ and of cerebellar granule cells in culture. Melatonin is known to inhibit the activation of NF-κB and has a cytoprotective function. In this study, we evaluated whether the cytoprotective effect of melatonin depends on the state of activation of a mixed cerebellar culture that is composed predominantly of granule cells; we tested the effect of melatonin on cultured rat cerebellar cells stimulated or not with lipopolysaccharide (LPS. The addition of melatonin (0.1 nM-1 µM reduced the survival of naïve cells while inhibiting LPS-induced cell death. Melatonin (100 nM transiently (15 min inhibited the nuclear translocation of both NF-κB dimers (p50/p50, p50/RelA and, after 60 min, increased the activation of p50/RelA. Melatonin-induced p50/RelA activity in naïve cells resulted in the transcription of inducible nitric oxide synthase (iNOS and the production of NO. Otherwise, in cultures treated with LPS, melatonin blocked the LPS-induced activation of p50/RelA and the reduction in p50/p50 levels and inhibited iNOS expression and NO synthesis. Therefore, melatonin in vehicle-treated cells induces cell death, while it protects against LPS-induced cytotoxicity. In summary, we confirmed that melatonin is a neuroprotective drug when cerebellar cells are challenged; however, melatonin can also lead to cell death when the normal balance of the NF-κB pathway is disturbed. Our data provide a mechanistic basis for understanding the influence of cell context on the final output response of melatonin.

  18. A cerebellar learning model of vestibulo-ocular reflex adaptation in wild-type and mutant mice.

    Science.gov (United States)

    Clopath, Claudia; Badura, Aleksandra; De Zeeuw, Chris I; Brunel, Nicolas

    2014-05-21

    Mechanisms of cerebellar motor learning are still poorly understood. The standard Marr-Albus-Ito theory posits that learning involves plasticity at the parallel fiber to Purkinje cell synapses under control of the climbing fiber input, which provides an error signal as in classical supervised learning paradigms. However, a growing body of evidence challenges this theory, in that additional sites of plasticity appear to contribute to motor adaptation. Here, we consider phase-reversal training of the vestibulo-ocular reflex (VOR), a simple form of motor learning for which a large body of experimental data is available in wild-type and mutant mice, in which the excitability of granule cells or inhibition of Purkinje cells was affected in a cell-specific fashion. We present novel electrophysiological recordings of Purkinje cell activity measured in naive wild-type mice subjected to this VOR adaptation task. We then introduce a minimal model that consists of learning at the parallel fibers to Purkinje cells with the help of the climbing fibers. Although the minimal model reproduces the behavior of the wild-type animals and is analytically tractable, it fails at reproducing the behavior of mutant mice and the electrophysiology data. Therefore, we build a detailed model involving plasticity at the parallel fibers to Purkinje cells' synapse guided by climbing fibers, feedforward inhibition of Purkinje cells, and plasticity at the mossy fiber to vestibular nuclei neuron synapse. The detailed model reproduces both the behavioral and electrophysiological data of both the wild-type and mutant mice and allows for experimentally testable predictions.

  19. Ionic mechanisms of burst firing in dissociated Purkinje neurons.

    Science.gov (United States)

    Swensen, Andrew M; Bean, Bruce P

    2003-10-22

    Cerebellar Purkinje neurons have intrinsic membrane properties that favor burst firing, seen not only during complex spikes elicited by climbing fiber input but also with direct electrical stimulation of cell bodies. We examined the ionic conductances that underlie all-or-none burst firing elicited in acutely dissociated mouse Purkinje neurons by short depolarizing current injections. Blocking voltage-dependent calcium entry by cadmium or replacement of external calcium by magnesium enhanced burst firing, but it was blocked by cobalt replacement of calcium, probably reflecting block of sodium channels. In voltage-clamp experiments, we used the burst waveform of each cell as a voltage command and used ionic substitutions and pharmacological manipulations to isolate tetrodotoxin (TTX)-sensitive sodium current, P-type and T-type calcium current, hyperpolarization-activated cation current (Ih), voltage-activated potassium current, large-conductance calcium-activated potassium current, and small-conductance calcium-activated potassium (SK) current. Measured near the middle of the first interspike interval, TTX-sensitive sodium current carried the largest inward current, and T-type calcium current was also substantial. Current through P-type channels was large immediately after a spike but decayed rapidly. These inward currents were opposed by substantial components of voltage-dependent and calcium-dependent potassium current. Termination of the burst is caused partly by decay of sodium current, together with a progressive buildup of SK current after the first interspike interval. Although burst firing depends on the net balance between multiple large currents flowing after a spike, it is surprisingly robust, probably reflecting complex interactions between the exact voltage waveform and voltage and calcium dependence of the various currents.

  20. Evidence for evoked release of adenosine and glutamate from cultured cerebellar granule cells

    Energy Technology Data Exchange (ETDEWEB)

    Schousboe, A.; Frandsen, A.; Drejer, J. (Univ. of Copenhagen (Denmark))

    1989-09-01

    Evoked release of ({sup 3}H)-D-aspartate which labels the neurotransmitter glutamate pool in cultured cerebellar granule cells was compared with evoked release of adenosine from similar cultures. It was found that both adenosine and (3H)-D-aspartate could be released from the neurons in a calcium dependent manner after depolarization of the cells with either 10-100 microM glutamate or 50 mM KCl. Cultures of cerebellar granule cells treated with 50 microM kainate to eliminate GABAergic neurons behaved in the same way. This together with the observation that cultured astrocytes did not exhibit a calcium dependent, potassium stimulated adenosine release strongly suggest that cerebellar granule cells release adenosine in a neurotransmitter-like fashion together with glutamate which is the classical neurotransmitter of these neurons. Studies of the metabolism of adenosine showed that in the granule cells adenosine is rapidly metabolized to ATP, ADP, and AMP, but in spite of this, adenosine was found to be released preferential to ATP.

  1. Intra-cerebellar infusion of the protein kinase Mzeta (PKMζ) inhibitor ZIP disrupts eyeblink classical conditioning

    Science.gov (United States)

    Chihabi, Kutibh; Morielli, Anthony D.; Green, John T.

    2016-01-01

    PKM-ζ, a constitutively active N-terminal truncated form of PKC-ζ, has long been implicated in a cellular correlate of learning, long-term potentiation (LTP). Inhibition of PKM-ζ with Zeta-inhibitory peptide (ZIP) has been shown in many brain structures to disrupt maintenance of AMPA receptors, irreversibly disrupting numerous forms of learning and memory that have been maintained for weeks. Delay eyeblink conditioning (EBC) is an established model for the assessment of cerebellar learning; here, we show that PKC-ζ and PKM-ζ are highly expressed in the cerebellar cortex, with highest expression found in Purkinje cell (PC) nuclei. Despite being highly expressed in the cerebellar cortex, no studies have examined how regulation of cerebellar PKM-ζ may affect cerebellar-dependent learning and memory. Given its disruption of learning in other brain structures, we hypothesized that ZIP would also disrupt delay EBC. We have shown that infusion of ZIP into the lobulus simplex of the rat cerebellar cortex can indeed significantly disrupt delay EBC. PMID:26949968

  2. Early Cerebellar Network Shifting in Spinocerebellar Ataxia Type 6.

    Science.gov (United States)

    Falcon, M I; Gomez, C M; Chen, E E; Shereen, A; Solodkin, A

    2016-07-01

    Spinocerebellar ataxia 6 (SCA6), an autosomal dominant degenerative disease, is characterized by diplopia, gait ataxia, and incoordination due to severe progressive degeneration of Purkinje cells in the vestibulo- and spinocerebellum. Ocular motor deficits are common, including difficulty fixating on moving objects, nystagmus and disruption of smooth pursuit movements. In presymptomatic SCA6, there are alterations in saccades and smooth-pursuit movements. We sought to assess functional and structural changes in cerebellar connectivity associated with a visual task, hypothesizing that gradual changes would parallel disease progression. We acquired functional magnetic resonance imaging and diffusion tensor imaging data during a passive smooth-pursuit task in 14 SCA6 patients, representing a range of disease duration and severity, and performed a cross-sectional comparison of cerebellar networks compared with healthy controls. We identified a shift in activation from vermis in presymptomatic individuals to lateral cerebellum in moderate-to-severe cases. Concomitantly, effective connectivity between regions of cerebral cortex and cerebellum was at its highest in moderate cases, and disappeared in severe cases. Finally, we noted structural differences in the cerebral and cerebellar peduncles. These unique results, spanning both functional and structural domains, highlight widespread changes in SCA6 and compensatory mechanisms associated with cerebellar physiology that could be utilized in developing new therapies.

  3. Adenosine modulation of [Ca2+]i in cerebellar granular cells: multiple adenosine receptors involved.

    Science.gov (United States)

    Vacas, Javier; Fernández, Mercedes; Ros, Manuel; Blanco, Pablo

    2003-12-01

    Elimination of adenosine by addition of adenosine deaminase (ADA) to the media leads to alterations in intracellular free calcium concentration ([Ca(2+)](i)) in cerebellar granular cells. Adenosine deaminase brings about increases or decreases in [Ca(2+)](i) depending on the previous activation state of the cell. These effects are dependent on the catalytic activity of adenosine deaminase, since its previous catalytic inactivation with Hg(2+) prevents the above-mentioned changes in intracellular calcium. Extracellular calcium is required for the increase in [Ca(2+)](i) promoted by ADA. This rise is insensitive to thapsigargin, but sensitive to micromolar concentrations of Ni(2+). Toxins specific for L, N and P/Q calcium channels do not overtly reduce this effect. N(6)-Cyclopentyl adenosine (CPA), an A(1) receptor agonist, produces a partial reversion of ADA effects, while CGS21680, A(2A)/A(2B) receptor agonist, slightly enhances them. Expression of A(1), A(2A), A(2B) and A(3) adenosine receptor mRNAs was detected in cerebellar granular cell cultures. These results suggest that adenosine modulate [Ca(2+)](i) in cerebellar granule cells through different adenosine receptor subtypes which, at least in part, seem to act through R-type calcium channels.

  4. Cerebellar Structure and Function in Male Wistar-Kyoto Hyperactive Rats

    Science.gov (United States)

    Thanellou, Alexandra; Green, John T.

    2014-01-01

    Previous research has suggested that the Wistar-Kyoto Hyperactive (WKHA) rat strain may model some of the behavioral features associated with attention-deficit/hyperactivity disorder (ADHD). We have shown that, in cerebellar-dependent eyeblink conditioning, WKHA emit eyeblink CRs with shortened onset latencies. To further characterize the shortened CR onset latencies seen in WKHA rats, we examined 750-ms delay conditioning with either a tone CS or a light CS, we extended acquisition training, and we included Wistar rats as an additional, outbred control strain. Our results indicated that WKHAs learned more quickly and showed a shortened CR onset latency to a tone CS compared to both Wistar-Kyoto Hypertensive (WKHT) and Wistars. WKHAs and Wistars show a lengthening of CR onset latency over conditioning with a tone CS and an increasing confinement of CRs to the later part of the tone CS (inhibition of delay). WKHAs learned more quickly to a light CS only in comparison to WKHTs and showed a shortened CR onset latency only in comparison to Wistars. Wistars showed an increasing confinement of CRs to the late part of the light CS over conditioning. We used unbiased stereology to estimate the number of Purkinje and granule cells in the cerebellar cortex of the three strains. Our results indicated that WKHAs have more granule cells than Wistars and WKHTs and more Purkinje cells than Wistars. Results are discussed in terms of CS processing and cerebellar cortical contributions to EBC. PMID:23398437

  5. Modeled changes of cerebellar activity in mutant mice are predictive of their learning impairments

    Science.gov (United States)

    Badura, Aleksandra; Clopath, Claudia; Schonewille, Martijn; de Zeeuw, Chris I.

    2016-11-01

    Translating neuronal activity to measurable behavioral changes has been a long-standing goal of systems neuroscience. Recently, we have developed a model of phase-reversal learning of the vestibulo-ocular reflex, a well-established, cerebellar-dependent task. The model, comprising both the cerebellar cortex and vestibular nuclei, reproduces behavioral data and accounts for the changes in neural activity during learning in wild type mice. Here, we used our model to predict Purkinje cell spiking as well as behavior before and after learning of five different lines of mutant mice with distinct cell-specific alterations of the cerebellar cortical circuitry. We tested these predictions by obtaining electrophysiological data depicting changes in neuronal spiking. We show that our data is largely consistent with the model predictions for simple spike modulation of Purkinje cells and concomitant behavioral learning in four of the mutants. In addition, our model accurately predicts a shift in simple spike activity in a mutant mouse with a brainstem specific mutation. This combination of electrophysiological and computational techniques opens a possibility of predicting behavioral impairments from neural activity.

  6. Restoring cognitive functions using non-invasive brain stimulation techniques in patients with cerebellar disorders

    Directory of Open Access Journals (Sweden)

    Paul A Pope

    2014-04-01

    Full Text Available Numerous studies have highlighted the possibility of modulating the excitability of cerebro-cerebellar circuits bi-directionally using transcranial electrical brain stimulation, in a manner akin to that observed using magnetic stimulation protocols. It has been proposed that cerebellar stimulation activates Purkinje cells in the cerebellar cortex, leading to inhibition of the dentate nucleus, which exerts a tonic facilitatory drive onto motor and cognitive regions of cortex through a synaptic relay in the ventral-lateral thalamus. Some cerebellar deficits present with cognitive impairments if damage to non-motor regions of the cerebellum disrupts the coupling with cerebral cortical areas for thinking and reasoning. Indeed, white matter changes in the dentato-rubral tract correlate with cognitive assessments in patients with Friedreich ataxia, suggesting that this pathway is one component of the anatomical substrate supporting a cerebellar contribution to cognition. An understanding of the physiology of the cerebro-cerebellar pathway previously helped us to constrain our interpretation of results from two recent studies in which we showed cognitive enhancements in healthy participants during tests of arithmetic after electrical stimulation of the cerebellum, but only when task demands were high. Others studies have also shown how excitation of the prefrontal cortex can enhance performance in a variety of working memory tasks. Thus, future efforts might be guided towards neuro-enhancement in certain patient populations, using what is commonly termed 'non-invasive brain stimulation' as a cognitive rehabilitation tool to modulate cerebro-cerebellar circuits, or for stimulation over the cerebral cortex to compensate for decreased cerebellar drive to this region. This article will address these possibilities with a review of the relevant literature covering ataxias and cerebellar cognitive affective disorders, which are characterized by thalamo

  7. Restoring cognitive functions using non-invasive brain stimulation techniques in patients with cerebellar disorders.

    Science.gov (United States)

    Pope, Paul A; Miall, R Chris

    2014-01-01

    Numerous studies have highlighted the possibility of modulating the excitability of cerebro-cerebellar circuits bi-directionally using transcranial electrical brain stimulation, in a manner akin to that observed using magnetic stimulation protocols. It has been proposed that cerebellar stimulation activates Purkinje cells in the cerebellar cortex, leading to inhibition of the dentate nucleus, which exerts a tonic facilitatory drive onto motor and cognitive regions of cortex through a synaptic relay in the ventral-lateral thalamus. Some cerebellar deficits present with cognitive impairments if damage to non-motor regions of the cerebellum disrupts the coupling with cerebral cortical areas for thinking and reasoning. Indeed, white matter changes in the dentato-rubral tract correlate with cognitive assessments in patients with Friedreich ataxia, suggesting that this pathway is one component of the anatomical substrate supporting a cerebellar contribution to cognition. An understanding of the physiology of the cerebro-cerebellar pathway previously helped us to constrain our interpretation of results from two recent studies in which we showed cognitive enhancements in healthy participants during tests of arithmetic after electrical stimulation of the cerebellum, but only when task demands were high. Others studies have also shown how excitation of the prefrontal cortex can enhance performance in a variety of working memory tasks. Thus, future efforts might be guided toward neuro-enhancement in certain patient populations, using what is commonly termed "non-invasive brain stimulation" as a cognitive rehabilitation tool to modulate cerebro-cerebellar circuits, or for stimulation over the cerebral cortex to compensate for decreased cerebellar drive to this region. This article will address these possibilities with a review of the relevant literature covering ataxias and cerebellar cognitive affective disorders, which are characterized by thalamo-cortical disturbances.

  8. Talpid3-binding centrosomal protein Cep120 is required for centriole duplication and proliferation of cerebellar granule neuron progenitors.

    Directory of Open Access Journals (Sweden)

    Chuanqing Wu

    Full Text Available Granule neuron progenitors (GNPs are the most abundant neuronal type in the cerebellum. GNP proliferation and thus cerebellar development require Sonic hedgehog (Shh secreted from Purkinje cells. Shh signaling occurs in primary cilia originating from the mother centriole. Centrioles replicate only once during a typical cell cycle and are responsible for mitotic spindle assembly and organization. Recent studies have linked cilia function to cerebellar morphogenesis, but the role of centriole duplication in cerebellar development is not known. Here we show that centrosomal protein Cep120 is asymmetrically localized to the daughter centriole through its interaction with Talpid3 (Ta3, another centrosomal protein. Cep120 null mutant mice die in early gestation with abnormal heart looping. Inactivation of Cep120 in the central nervous system leads to both hydrocephalus, due to the loss of cilia on ependymal cells, and severe cerebellar hypoplasia, due to the failed proliferation of GNPs. The mutant GNPs lack Hedgehog pathway activity. Cell biological studies show that the loss of Cep120 results in failed centriole duplication and consequently ciliogenesis, which together underlie Cep120 mutant cerebellar hypoplasia. Thus, our study for the first time links a centrosomal protein necessary for centriole duplication to cerebellar morphogenesis.

  9. Is bilirubin able to affect the cell cycle in Gunn rat brain? - An in vivo and in vitro study -

    OpenAIRE

    Robert, Maria Celeste

    2012-01-01

    The hyperbilirubinemic jj Gunn rat is a well established animal model for Crigler-Najjar type I Syndrome and neonatal jaundice. Similarly to humans, they present neurological deficits and what is more a marked cerebellar hypoplasia with a prominent loss and degeneration of Purkinje cells and granule neurons. Since high levels of bilirubin have been proven to arrest the cell cycle progression, we addressed the question if the cerebellar hypoplasia observed in the hyperbilirubinemic Gunn rat co...

  10. Neuropathological features in a female fetus with OPHN1 deletion and cerebellar hypoplasia.

    Science.gov (United States)

    Rocas, Delphine; Alix, Eudeline; Michel, Jessica; Cordier, Marie-Pierre; Labalme, Audrey; Guilbert, Hélène; Till, Marianne; Schluth-Bolard, Caroline; de Haas, Pascale; Massardier, Jérôme; Portes, Vincent des; Edery, Patrick; Touraine, Renaud; Guibaud, Laurent; Vasiljevic, Alexandre; Sanlaville, Damien

    2013-05-01

    We report the case of a 33-year-old pregnant woman. The third-trimester ultrasound scan during pregnancy revealed fetal bilateral ventricular dilatation, macrosomia and a transverse diameter of the cerebellum at the 30th centile. A brain MRI scan at 31 weeks of gestation led to a diagnosis of hypoplasia of the cerebellar vermis without hemisphere abnormalities and a non compressive expansion of the cisterna magna. The fetal karyotype was 46,XX. The pregnancy was terminated and array-CGH analysis of the fetus identified a 238 kb de novo deletion on chromosome Xp12, encompassing part of OPHN1 gene. Further studies revealed a completely skewed pattern of X inactivation. OPHN1 is involved in X-linked mental retardation (XLMR) with cerebellar hypoplasia and encodes a Rho-GTPase-activating protein called oligophrenin-1, which is produced throughout the developing mouse brain and in the hippocampus and Purkinje cells of the cerebellum in adult mice. Neuropathological examination of the female fetus revealed cerebellar hypoplasia and the heterotopia of Purkinje cells at multiple sites in the white matter of the cerebellum. This condition mostly affects male fetuses in humans. We report here the first case of a de novo partial deletion of OPHN1, with radiological and neuropathological examination, in a female fetus.

  11. Purinergic P2X7 receptors mediate cell death in mouse cerebellar astrocytes in culture.

    Science.gov (United States)

    Salas, Elvira; Carrasquero, Luz María G; Olivos-Oré, Luis A; Bustillo, Diego; Artalejo, Antonio R; Miras-Portugal, Maria Teresa; Delicado, Esmerilda G

    2013-12-01

    The brain distribution and functional role of glial P2X7 receptors are broader and more complex than initially anticipated. We characterized P2X7 receptors from cerebellar astrocytes at the molecular, immunocytochemical, biophysical, and cell physiologic levels. Mouse cerebellar astrocytes in culture express mRNA coding for P2X7 receptors, which is translated into P2X7 receptor protein as proven by Western blot analysis and immunocytochemistry. Fura-2 imaging showed cytosolic calcium responses to ATP and the synthetic analog 3'-O-(4-benzoyl)benzoyl-ATP (BzATP) exhibited two components, namely an initial transient and metabotropic component followed by a sustained one that depended on extracellular calcium. This latter component, which was absent in astrocytes from P2X7 receptor knockout mice (P2X7 KO), was modulated by extracellular Mg(2+), and was sensitive to Brilliant Blue G (BBG) and 3-(5-(2,3-dichlorophenyl)-1H-tetrazol-1-yl)methyl pyridine (A438079) antagonism. BzATP also elicited inwardly directed nondesensitizing whole-cell ionic currents that were reduced by extracellular Mg(2+) and P2X7 antagonists (BBG and calmidazolium). In contrast to that previously reported in rat cerebellar astrocytes, sustained BzATP application induced a gradual increase in membrane permeability to large cations, such as N-methyl-d-glucamine and 4-[3-methyl-2(3H)-benzoxazolylidene)-methyl]-1-[3-(triethylammonio)propyl]diiodide, which ultimately led to the death of mouse astrocytes. Cerebellar astrocyte cell death was prevented by BBG but not by calmidazolium, removal of extracellular calcium, or treatment with the caspase-3 inhibitor, benzyloxycarbonyl-Asp(OMe)-Glu(OMe)-Val-Asp(OMe)-fluoromethylketone, thus suggesting a necrotic-type mechanism of cell death. Since this cellular response was not observed in astrocytes from P2X7 KO mice, this study suggests that stimulation of P2X7 receptor may convey a cell death signal to cerebellar astrocytes in a species-specific manner.

  12. β-Catenin is critical for cerebellar foliation and lamination.

    Directory of Open Access Journals (Sweden)

    Jing Wen

    Full Text Available The cerebellum has a conserved foliation pattern and a well-organized layered structure. The process of foliation and lamination begins around birth. β-catenin is a downstream molecule of Wnt signaling pathway, which plays a critical role in tissue organization. Lack of β-catenin at early embryonic stages leads to either prenatal or neonatal death, therefore it has been difficult to resolve its role in cerebellar foliation and lamination. Here we used GFAP-Cre to ablate β-catenin in neuronal cells of the cerebellum after embryonic day 12.5, and found an unexpected role of β-catenin in determination of the foliation pattern. In the mutant mice, the positions of fissure formation were changed, and the meninges were improperly incorporated into fissures. At later stages, some lobules were formed by Purkinje cells remaining in deep regions of the cerebellum and the laminar structure was dramatically altered. Our results suggest that β-catenin is critical for cerebellar foliation and lamination. We also found a non cell-autonomous role of β-catenin in some developmental properties of major cerebellar cell types during specific stages.

  13. FGF-2 signal promotes proliferation of cerebellar progenitor cells and their oligodendrocytic differentiation at early postnatal stage

    Energy Technology Data Exchange (ETDEWEB)

    Naruse, Masae; Shibasaki, Koji; Ishizaki, Yasuki, E-mail: yasukiishizaki@gunma-u.ac.jp

    2015-08-07

    The origins and developmental regulation of cerebellar oligodendrocytes are largely unknown, although some hypotheses of embryonic origins have been suggested. Neural stem cells exist in the white matter of postnatal cerebellum, but it is unclear whether these neural stem cells generate oligodendrocytes at postnatal stages. We previously showed that cerebellar progenitor cells, including neural stem cells, widely express CD44 at around postnatal day 3. In the present study, we showed that CD44-positive cells prepared from the postnatal day 3 cerebellum gave rise to neurospheres, while CD44-negative cells prepared from the same cerebellum did not. These neurospheres differentiated mainly into oligodendrocytes and astrocytes, suggesting that CD44-positive neural stem/progenitor cells might generate oligodendrocytes in postnatal cerebellum. We cultured CD44-positive cells from the postnatal day 3 cerebellum in the presence of signaling molecules known as mitogens or inductive differentiation factors for oligodendrocyte progenitor cells. Of these, only FGF-2 promoted survival and proliferation of CD44-positive cells, and these cells differentiated into O4+ oligodendrocytes. Furthermore, we examined the effect of FGF-2 on cerebellar oligodendrocyte development ex vivo. FGF-2 enhanced proliferation of oligodendrocyte progenitor cells and increased the number of O4+ and CC1+ oligodendrocytes in slice cultures. These results suggest that CD44-positive cells might be a source of cerebellar oligodendrocytes and that FGF-2 plays important roles in their development at an early postnatal stage. - Highlights: • CD44 is expressed in cerebellar neural stem/progenitor cells at postnatal day 3 (P3). • FGF-2 promoted proliferation of CD44-positive progenitor cells from P3 cerebellum. • FGF-2 promoted oligodendrocytic differentiation of CD44-positive progenitor cells. • FGF-2 increased the number of oligodendrocytes in P3 cerebellar slice culture.

  14. The cerebellar Golgi cell and spatiotemporal organization of granular layer activity

    Directory of Open Access Journals (Sweden)

    Egidio eD‘Angelo

    2013-05-01

    Full Text Available The cerebellar granular layer has been suggested to perform a complex spatiotemporal reconfiguration of incoming mossy fiber signals. Central to this role is the inhibitory action exerted by Golgi cells over granule cells: Golgi cells inhibit granule cells through double feedforward and feedback inhibitory loops and generate a broad lateral inhibition that extends beyond the afferent synaptic field. This characteristic connectivity has recently been investigated in great detail and been correlated with specific functional properties of the neuron. These include theta-frequency pacemaking, network entrainment into coherent oscillations and phase resetting. Important advances have also been made in terms of determining the membrane and synaptic properties of the neuron, and clarifying the mechanisms of activation by input bursts. Moreover, voltage sensitive dye imaging and multi-electrode array recordings, combined with mathematical simulations based on realistic computational models, have improved our understanding of the impact of Golgi cell activity on granular layer circuit computations. These investigations have highlighted the critical role of Golgi cells in: generating dense clusters of granule cell activity organized in center-surround structures, implementing combinatorial operations on multiple mossy fiber inputs, regulating transmission gain and cut-off frequency, controlling spike timing and burst transmission, and determining the sign, intensity and extension of long-term synaptic plasticity at the mossy fiber-granule cell relay. This review considers recent advances in the field, highlighting the functional implications of Golgi cells for granular layer network computation and indicating new challenges for cerebellar research.

  15. Silent synapses, LTP, and the indirect parallel-fibre pathway: computational consequences of optimal cerebellar noise-processing.

    Directory of Open Access Journals (Sweden)

    John Porrill

    2008-05-01

    Full Text Available Computational analysis of neural systems is at its most useful when it uncovers principles that provide a unified account of phenomena across multiple scales and levels of description. Here we analyse a widely used model of the cerebellar contribution to sensori-motor learning to demonstrate both that its response to intrinsic and sensor noise is optimal, and that the unexpected synaptic and behavioural consequences of this optimality can explain a wide range of experimental data. The response of the Marr-Albus adaptive-filter model of the cerebellar microcircuit to noise was examined in the context of vestibulo-ocular reflex calibration. We found that, when appropriately connected, an adaptive-filter model using the covariance learning rule to adjust the weights of synapses between parallel fibres and Purkinje cells learns weight values that are optimal given the relative amount of signal and noise carried by each parallel fibre. This optimality principle is consistent with data on the cerebellar role in smooth pursuit eye movements, and predicts that many synaptic weights must be very small, providing an explanation for the experimentally observed preponderance of silent synapses. Such a preponderance has in its turn two further consequences. First, an additional inhibitory pathway from parallel fibre to Purkinje cell is required if Purkinje cell activity is to be altered in either direction from a starting point of silent synapses. Second, cerebellar learning tasks must often proceed via LTP, rather than LTD as is widely assumed. Taken together, these considerations have profound behavioural consequences, including the optimal combination of sensori-motor information, and asymmetry and hysteresis of sensori-motor learning rates.

  16. Paraneoplastic cerebellar degeneration with anti-Yo antibodies - a review.

    Science.gov (United States)

    Venkatraman, Anand; Opal, Puneet

    2016-08-01

    The ataxic syndrome associated with Anti-Yo antibody, or Purkinje cell cytoplasmic antibody type 1 (PCA1), is the most common variant of paraneoplastic cerebellar degeneration (PCD). The typical presentation involves the subacute development of pancerebellar deficits with a clinical plateau within 6 months. The vast majority of cases have been reported in women with pelvic or breast tumors. Magnetic resonance imaging of the brain is often normal in the early stages, with cerebellar atrophy seen later. The underlying mechanism is believed to be an immunological reaction to cerebellar degeneration-related protein 2 (CDR2), a protein usually found in the cerebellum that is ectopically produced by tumor cells. Although both B- and T-cell abnormalities are seen, there is debate about the relative importance of the autoantibodies and cytotoxic T lymphocytes in the neuronal loss. Cerebrospinal fluid abnormalities, primarily elevated protein, lymphocytic pleocytosis, and oligoclonal bands, are common in the early stages. The low prevalence of this condition has not allowed for large-scale randomized controlled trials. Immunotherapies, such as steroids, intravenous immune globulins, and plasma exchange, have been extensively used in managing this condition, with limited success. Although some reports indicate benefit from antitumor therapies like surgery and chemotherapy, this has not been consistently observed. The prognosis for anti-Yo PCD is almost uniformly poor, with most patients left bedridden. Further studies are required to clarify the pathophysiology and provide evidence-based treatment options.

  17. Lack of connexin43-mediated Bergmann glial gap junctional coupling does not affect cerebellar long-term depression, motor coordination, or eyeblink conditioning

    Directory of Open Access Journals (Sweden)

    Mika Tanaka

    2008-04-01

    Full Text Available Bergmann glial cells are specialized astrocytes in the cerebellum. In the mature cerebellar molecular layer, Bergmann glial processes are closely associated with Purkinje cells, enclosing Purkinje cell dendritic synapses with a glial sheath. There is intensive gap junctional coupling between Bergmann glial processes, but their significance in cerebellar functions is not known. Connexin43 (Cx43, a major component of astrocytic gap junction channels, is abundantly expressed in Bergmann glial cells. To examine the role of Cx43-mediated gap junctions between Bergmann glial cells in cerebellar functions, we generated Cx43 conditional knockout mice with the S100b-Cre transgenic line (Cx43fl/fl:S100b-Cre, which exhibited a significant loss of Cx43 in the Bergmann glial cells and astrocytes in the cerebellum with a postnatal onset. The Cx43fl/fl:S100b-Cre mice had normal cerebellar architecture. Although gap junctional coupling between the Bergmann glial cells measured by spreading of microinjected Lucifer yellow was virtually abolished in Cx43fl/fl:S100b-Cre mice, electrophysiologic analysis revealed that cerebellar long-term depression could be induced and maintained normally in thier cerebellar slices. In addition, at the behavioral level, Cx43fl/fl:S100b-Cre mice had normal motor coordination in the rotarod task and normal conditioned eyelid response. Our findings suggest that Cx43-mediated gap junctional coupling between Bergmann glial cells is not necessary for the neuron-glia interactions required for cerebellum-dependent motor coordination and motor learning.

  18. 阿片样肽类的微离子透入对猫小脑浦肯野氏细胞的作用%Effects of microiontophoretically-applied opioid peptides on Purkinje cells in the cat cerebellum

    Institute of Scientific and Technical Information of China (English)

    Kyoji TAGUCHI; Kenji ABE; Touichiro CHYUMA; Masatoshi KATO; Toshiro SHIGENAGA; Kazuki KUSHIDA; Toshiyuki CHIKUMA

    2000-01-01

    AIM: The purpose of the present study was to examine the effects of microiontophoretically-applied opioid peptides on Purkinje cell of the cerebellum. METHODS:The effects of microiontophoretically-applied morphine,leucine-enkephalin ( Leu-Enk ), methionine-enkephalin (Met-Enk), and dynorphin 1- 13 (Dyn) on the spontaneous discharge of Purkinje cells in the cerebellum of the anesthetized cat were examined. RESULTS: Microiontophoretic applications of Leu-Enk and morphine produced inhibitory and excitatory responses, respectively in Purkinje cells. Application of both morphine and Leu-Enk induced dose-dependent responses. The excitatory responses were antagonized by naloxone, whereas the inhibitory responses were not. Bicuculline, a GABA-Aantagonist, completely abolished both the Leu-Enk-and morphine-induced-inhibitory responses. Iontophoretic application of Met-Enk and dyn produced inhibitory responses only. Met-enk- and dyn-induced inhibition was antagonized by naloxone. CONCLUSION: In Purkinje cell activity, microiontophoretically applied Leu-Enk-and morphine-induced excitation is connected with opiate receptors, whereas inhibition is related to the GABA receptor. However, Met-Enk and dyn produced only inhibitory effects via an opiate receptor in the cerebellum of cats.

  19. Progressive Purkinje cell degeneration in tambaleante mutant mice is a consequence of a missense mutation in HERC1 E3 ubiquitin ligase.

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    Tomoji Mashimo

    2009-12-01

    Full Text Available The HERC gene family encodes proteins with two characteristic domains: HECT and RCC1-like. Proteins with HECT domains have been described to function as ubiquitin ligases, and those that contain RCC1-like domains have been reported to function as GTPases regulators. These two activities are essential in a number of important cellular processes such as cell cycle, cell signaling, and membrane trafficking. Mutations affecting these domains have been found associated with retinitis pigmentosa, amyotrophic lateral sclerosis, and cancer. In humans, six HERC genes have been reported which encode two subgroups of HERC proteins: large (HERC1-2 and small (HERC3-6. The giant HERC1 protein was the first to be identified. It has been involved in membrane trafficking and cell proliferation/growth through its interactions with clathrin, M2-pyruvate kinase, and TSC2 proteins. Mutations affecting other members of the HERC family have been found to be associated with sterility and growth retardation. Here, we report the characterization of a recessive mutation named tambaleante, which causes progressive Purkinje cell degeneration leading to severe ataxia with reduced growth and lifespan in homozygous mice aged over two months. We mapped this mutation in mouse chromosome 9 and then performed positional cloning. We found a GA transition at position 1448, causing a Gly to Glu substitution (Gly483Glu in the highly conserved N-terminal RCC1-like domain of the HERC1 protein. Successful transgenic rescue, with either a mouse BAC containing the normal copy of Herc1 or with the human HERC1 cDNA, validated our findings. Histological and biochemical studies revealed extensive autophagy associated with an increase of the mutant protein level and a decrease of mTOR activity. Our observations concerning this first mutation in the Herc1 gene contribute to the functional annotation of the encoded E3 ubiquitin ligase and underline the crucial and unexpected role of this protein

  20. TOTAL NUMBER: A BRIEF REVIEW OF ITS IMPORTANCE AND ITS USE IN ASSESSING CEREBELLAR DAMAGE IN THE RAT FOLLOWING EARLY POSTNATAL ALCOHOL EXPOSURE

    Directory of Open Access Journals (Sweden)

    Ruth MA Napper

    2011-05-01

    Full Text Available Knowledge of the total number of structural components that make up the various neural networks within the central nervous system is fundamental to our understanding of its normal function and of dysfunction that may accompany injury and disease. This paper briefly reviews the methodology currently used to estimate number and discusses the importance of unbiased estimates of total number in determining changes in brain structure that may underlie dysfunction. An example from the olfactory bulb is used to demonstrate the potential invalidity of using estimates of total number of objects per single section. Exposure to alcohol during the early postnatal period results in motor dysfunction in adult rats. This paper presents data on the extent and magnitude of cell loss within the cerebellar network of the rat following alcohol exposure during postnatal days 4 to 9. High transient blood alcohol concentrations result in a Purkinje cell of 27% across the entire cerebellum but with regional variabiltiy, vermal lobule X has a 43% Purkinje cell deficit. This alcohol regimen also results in a neuronal loss of 28% and 25% within the deep cerebellar nucleus and inferior olivary nucleus respectively. Consistency of overall neuronal loss across diverse neuronal populations within the cerebellar network is discussed in the context of the maintenance of cerebellar connectivity.

  1. Cerebellar Mutism

    OpenAIRE

    1994-01-01

    Of a series of 15 children operated for cerebellar tumor at University Hospital Rotterdam-Dijkzigt, The Netherlands, 5 developed “cerebellar mutism” and subsequent dysarthria after surgery, and 2 had mild speech problems.

  2. Spontaneous calcium waves in granule cells in cerebellar slice cultures

    DEFF Research Database (Denmark)

    Apuschkin, Mia; Ougaard, Maria; Rekling, Jens C

    2013-01-01

    and establishment of synaptic transmission. Here, we used calcium imaging in slice cultures of the postnatal cerebellum, and observe spontaneous propagating calcium waves in NeuN-positive granule-like cells. Wave formation was blocked by TTX and the AMPA antagonist NBQX, but persisted after NMDA receptor blockade...

  3. A magnetic resonance imaging study of cerebellar volume in tuberous sclerosis complex.

    Science.gov (United States)

    Weisenfeld, Neil I; Peters, Jurriaan M; Tsai, Peter T; Prabhu, Sanjay P; Dies, Kira A; Sahin, Mustafa; Warfield, Simon K

    2013-02-01

    The cerebellum plays an important role in motor learning and cognition, and structural cerebellar abnormalities have been associated with cognitive impairment. In tuberous sclerosis complex, neurologic outcome is highly variable, and no consistent imaging or pathologic determinant of cognition has been firmly established. The cerebellum calls for specific attention because mouse models of tuberous sclerosis complex have demonstrated a loss of cerebellar Purkinje cells, and cases of human histologic data have demonstrated a similar loss in patients. We hypothesized that there might be a common cerebellar finding in tuberous sclerosis complex that could be measured as morphometric changes with magnetic resonance imaging. Using a robust, automated image analysis procedure, we studied 36 patients with tuberous sclerosis complex and age-matched control subjects and observed significant volume loss among patients in the cerebellar cortices and vermis. Furthermore, this effect was strongest in a subgroup of 19 patients with a known, pathogenic mutation of the tuberous sclerosis 2 gene and impacted all cerebellar structures. We conclude that patients with tuberous sclerosis complex exhibit volume loss in the cerebellum, and this loss is larger and more widespread in patients with a tuberous sclerosis 2 mutation.

  4. Contribution of plasma membrane Ca2+ ATPase to cerebellar synapse function

    Institute of Scientific and Technical Information of China (English)

    Helena; Huang; Raghavendra; Y; Nagaraja; Molly; L; Garside; Walther; Akemann; Thomas; Knpfel; Ruth; M; Empson

    2010-01-01

    The cerebellum expresses one of the highest levels of the plasma membrane Ca2+ATPase,isoform 2 in the mammalian brain.This highly efficient plasma membrane calcium transporter protein is enriched within the main output neurons of the cerebellar cortex;i.e. the Purkinje neurons(PNs) .Here we review recent evidence,including electrophysiological and calcium imaging approaches using the plasma membrane calcium ATPase 2(PMCA2) knockout mouse,to show that PMCA2 is critical for the physiological control of calcium at cerebellar synapses and cerebellar dependent behaviour.These studies have also revealed that deletionof PMCA2 throughout cerebellar development in the PMCA2 knockout mouse leads to permanent signalling and morphological alterations in the PN dendrites. Whilst these findings highlight the importance of PMCA2 during cerebellar synapse function and development,they also reveal some limitations in the use of the PMCA2 knockout mouse and the need for additional experimental approaches including cell-specific and reversible manipulation of PMCAs.

  5. Morphological changes in the frog cerebellar cortex after unilateral section of the statoacustic nerve

    Directory of Open Access Journals (Sweden)

    D. Necchi

    2010-05-01

    Full Text Available To investigate a possible role of the cerebellum in vestibular compensation that follows a lesion to the vestibular apparatus, the morphological changes of the cerebellar cortex of adult frogs following unilateral statoacustic nerve section was analyzed by means of electron microscopy starting from 3 days after the neurectomy for up to 6 months. On the ipsilateral side, massive abnormality was found in all layers at early postsurgical intervals. This involved both nerve fibers and cell bodies. Fibers often appeared condensed or vacuolated with poorly compacted myelin sheath. Cells had electronlucent and vacuolated cytoplasm to varying extent. Alterations became less conspicuous after 30 days and after 60 days altered nerve cells were no longer present. On the contralateral side, only a few Purkinje and granule cells were affected at early postsurgical stages. This may derive from the fact that, in the frog, some of the vestibular primary afferents reach contralateral cerebellar cortex. At 30 days, alterations had substantially progressed, and at 60 days they involved all the cortical layers. Fiber debris was present in the granular and molecular layers and numerous 317 Purkinje cells were electrondense and shrunken. This lateness in alteration may be a consequence of the prolonged silence of the vestibular nucleus contralateral to the lesion. At 4 and 6 months the tissue architecture was normal.

  6. Temporal development of GABA agonist induced alterations in ultrastructure and GABA receptor expression in cultured cerebellar granule cells

    DEFF Research Database (Denmark)

    Hansen, G H; Belhage, B; Schousboe, A

    1987-01-01

    . It was found that the cytoplasmic density of smooth endoplasmic reticulum was decreased, while the cytoplasmic density of rough endoplasmic reticulum, Golgi apparatus, vesicles and coated vesicles was greatly enhanced after exposure of the cells to THIP (150 microM) for only 1 hr. In cerebellar granule cells...

  7. Depletion of polyamines prevents the neurotrophic activity of the GABA-agonist THIP in cultured rat cerebellar granule cells

    DEFF Research Database (Denmark)

    Abraham, J H; Hansen, Gert Helge; Seiler, N

    1993-01-01

    Effects of polyamine depletion by alpha-difluoromethylornithine (DFMO) were studied on the GABA-agonist mediated enhancement of the morphological development of cultured rat cerebellar granule cells. An increase in the number of neurite extending cells and in the cytoplasmic density of organelles...... endoplasmic reticulum, Golgi apparatus and different types of vesicles was prevented by the exposure to DFMO....

  8. Temporal development of GABA agonist induced alterations in ultrastructure and GABA receptor expression in cultured cerebellar granule cells

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Belhage, B; Schousboe, A;

    1987-01-01

    The temporal development of the effect of THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) on the ultrastructure composition and GABA receptor expression in cerebellar granule cells was investigated by quantitative electron microscopy (morphometric analysis) and GABA binding assays...... exposed to THIP (150 microM) for 3 hr low affinity GABA receptors were induced. These findings show that the effect of THIP on the ultrastructure composition and GABA receptor expression in cultured cerebellar granule cells may be interrelated and moreover it is likely that the turn-over of GABA receptors...

  9. Early maternal deprivation in rats induces gender-dependent effects on developing hippocampal and cerebellar cells.

    Science.gov (United States)

    Llorente, Ricardo; Gallardo, Meritxell López; Berzal, Alvaro Llorente; Prada, Carmen; Garcia-Segura, Luis Miguel; Viveros, María-Paz

    2009-05-01

    Adult animals submitted to a single prolonged episode of maternal deprivation [24h, postnatal day 9-10] show behavioral alterations that resemble specific symptoms of schizophrenia. According to the neurodevelopmental theory, these behavioral deficits might be mediated by detrimental neurodevelopmental processes that might be associated, at least partially, with stress-induced corticosterone responses. In order to address this hypothesis, we have focused on the hippocampus and cerebellar cortex, two brain regions that show high density of glucocorticoid receptors, and analyzed possible neuronal and glial alterations by immunohistochemical techniques. To evaluate the presence of degenerated neurons we used Fluoro-Jade-C (FJ-C) staining and for the study of astrocytes we employed glial fibrillary acidic protein (GFAP). Within control animals, females showed significantly more GFAP positive cells than males and a trend towards more FJ-C positive cells. Maternal deprivation induced neuronal degeneration and astroglial changes in the hippocampus and cerebellar cortex of neonatal rats that, in general, were more marked in males. This differential effect may be attributable to a greater vulnerability of males to this kind of early environmental insult and/or to sex-dependent differences in the onset and/or progression of the effects. The present experimental procedure may be instrumental in elucidating sex-dependent mechanisms of neurodevelopmental psychiatric disorders with a basis in early environmental insults.

  10. The apical complex protein Pals1 is required to maintain cerebellar progenitor cells in a proliferative state.

    Science.gov (United States)

    Park, Jun Young; Hughes, Lucinda J; Moon, Uk Yeol; Park, Raehee; Kim, Sang-Bae; Tran, Khoi; Lee, Ju-Seog; Cho, Seo-Hee; Kim, Seonhee

    2016-01-01

    Through their biased localization and function within the cell, polarity complex proteins are necessary to establish the cellular asymmetry required for tissue organization. Well-characterized germinal zones, mitogenic signals and cell types make the cerebellum an excellent model for addressing the crucial function of polarity complex proteins in the generation and organization of neural tissues. Deletion of the apical polarity complex protein Pals1 in the developing cerebellum results in a remarkably undersized cerebellum with disrupted layers in poorly formed folia and strikingly reduced granule cell production. We demonstrate that Pals1 is not only essential for cerebellum organogenesis, but also for preventing premature differentiation and thus maintaining progenitor pools in cerebellar germinal zones, including cerebellar granule neuron precursors in the external granule layer. In the Pals1 mouse mutants, the expression of genes that regulate the cell cycle was diminished, correlating with the loss of the proliferating cell population of germinal zones. Furthermore, enhanced Shh signaling through activated Smo cannot overcome impaired cerebellar cell generation, arguing for an epistatic role of Pals1 in proliferation capacity. Our study identifies Pals1 as a novel intrinsic factor that regulates the generation of cerebellar cells and Pals1 deficiency as a potential inhibitor of overactive mitogenic signaling.

  11. Growth hormone-releasing peptide-6 inhibits cerebellar cell death in aged rats.

    Science.gov (United States)

    Pañeda, Covadonga; Arroba, Ana I; Frago, Laura M; Holm, Anne Mette; Rømer, John; Argente, Jesús; Chowen, Julie A

    2003-08-26

    Insulin-like growth factor (IGF)-I is essential for cerebellar granule neuron survival and a decline in IGF-I is implicated in various age-dependent processes. Here we show that IGF-I mRNA levels are decreased in the cerebellum of old rats compared with young rats and this was associated with increased cell death and activation of caspases 3 and 9. Growth hormone-releasing peptide (GHRP)-6, a synthetic ligand for the ghrelin receptor, increased IGF-I mRNA levels, decreased cell death and inhibited caspase 3 and 9 activation in the cerebellum of aged rats. These results suggest that increasing IGF-I expression in the cerebellum can decrease cell death in aged rats via inhibition of caspase 3 and 9 activation.

  12. Age-related changes of structures in cerebellar cortex of cat

    Indian Academy of Sciences (India)

    Changzheng Zhang; Tianmiao Hua; Zaiman Zhu; Xun Luo

    2006-03-01

    We studied the structures of the cerebellar cortex of young adult and old cats for age-related changes, which were statistically analysed. Nissl staining was used to visualize the cortical neurons. The immunohistochemical method was used to display glial fibrillary acidic protein (GFAP)-immunoreactive (IR) astrocytes and neurofilament-immunoreactive (NF-IR) neurons. Under the microscope, the thickness of the cerebellar cortex was measured; and the density of neurons in all the layers as well as that of GFAP-IR cells in the granular layer was analysed. Compared with young adult cats, the thickness of the molecular layer and total cerebellar cortex was significantly decreased in old cats, and that of the granular layer increased. The density of neurons in each layer was significantly lower in old cats than in young adult ones. Astrocytes in old cats were significantly denser than in young adult ones, and accompanied by evident hypertrophy of the cell bodies and enhanced immunoreaction of GFAP substance. Purkinje cells (PCs) in old cats showed much fewer NF-IR dendrites than those in young adults. The above findings indicate a loss of neurons and decrease in the number of dendrites of the PCs in the aged cerebellar cortex, which might underlie the functional decline of afferent efficacy and information integration in the senescent cerebellum. An age-dependent enhancement of activity of the astrocytes may exert a protective effect on neurons in the aged cerebellum.

  13. Bmi1 overexpression in the cerebellar granule cell lineage of mice affects cell proliferation and survival without initiating medulloblastoma formation

    Directory of Open Access Journals (Sweden)

    Hourinaz Behesti

    2013-01-01

    BMI1 is a potent inducer of neural stem cell self-renewal and neural progenitor cell proliferation during development and in adult tissue homeostasis. It is overexpressed in numerous human cancers – including medulloblastomas, in which its functional role is unclear. We generated transgenic mouse lines with targeted overexpression of Bmi1 in the cerebellar granule cell lineage, a cell type that has been shown to act as a cell of origin for medulloblastomas. Overexpression of Bmi1 in granule cell progenitors (GCPs led to a decrease in cerebellar size due to decreased GCP proliferation and repression of the expression of cyclin genes, whereas Bmi1 overexpression in postmitotic granule cells improved cell survival in response to stress by altering the expression of genes in the mitochondrial cell death pathway and of Myc and Lef-1. Although no medulloblastomas developed in ageing cohorts of transgenic mice, crosses with Trp53−/− mice resulted in a low incidence of medulloblastoma formation. Furthermore, analysis of a large collection of primary human medulloblastomas revealed that tumours with a BMI1high TP53low molecular profile are significantly enriched in Group 4 human medulloblastomas. Our data suggest that different levels and timing of Bmi1 overexpression yield distinct cellular outcomes within the same cellular lineage. Importantly, Bmi1 overexpression at the GCP stage does not induce tumour formation, suggesting that BMI1 overexpression in GCP-derived human medulloblastomas probably occurs during later stages of oncogenesis and might serve to enhance tumour cell survival.

  14. Effects of cerebellar transcranial alternating current stimulation on motor cortex excitability and motor function.

    Science.gov (United States)

    Naro, Antonino; Bramanti, Alessia; Leo, Antonino; Manuli, Alfredo; Sciarrone, Francesca; Russo, Margherita; Bramanti, Placido; Calabrò, Rocco Salvatore

    2017-01-07

    The cerebellum regulates several motor functions through two main mechanisms, the cerebellum-brain inhibition (CBI) and the motor surround inhibition (MSI). Although the exact cerebellar structures and functions involved in such processes are partially known, Purkinje cells (PC) and their surrounding interneuronal networks may play a pivotal role concerning CBI and MSI. Cerebellar transcranial alternating current stimulation (tACS) has been proven to shape specific cerebellar components in a feasible, safe, effective, and non-invasive manner. The aim of our study was to characterize the cerebellar structures and functions subtending CBI and MSI using a tACS approach. Fifteen healthy individuals underwent a cerebellar tACS protocol at 10, 50, and 300 Hz, or a sham-tACS over the right cerebellar hemisphere. We measured the tACS aftereffects on motor-evoked potential (MEP) amplitude, CBI induced by tACS (tiCBI) at different frequencies, MSI, and hand motor task performance. None of the participants had any side effect related to tACS. After 50-Hz tACS, we observed a clear tiCBI-50Hz weakening (about +30%, p  0.6). Our preliminary data suggest that PC may represent the last mediator of tiCBI and that the surrounding interneuronal network may have an important role in updating MSI, tiCBI, and M1 excitability during tonic muscle contraction, by acting onto the PC. The knowledge of these neurophysiological issues offers new cues to design innovative, non-invasive neuromodulation protocols to shape cerebellar-cerebral functions.

  15. Reappraisal of Bergmann glial cells as modulators of cerebellar circuit function

    Directory of Open Access Journals (Sweden)

    Chris I De Zeeuw

    2015-07-01

    Full Text Available Just as there is a huge morphological and functional diversity of neuron types specialized for specific aspects of information processing in the brain, astrocytes have equally distinct morphologies and functions that aid optimal functioning of the circuits in which they are embedded. One type of astrocyte, the Bergmann glial cell of the cerebellum, is a prime example of a highly diversified astrocyte type, the architecture of which is adapted to the cerebellar circuit and facilitates an impressive range of functions that optimize information processing in the adult brain. In this review we expand on the function of the Bergmann glial cell in the cerebellum to highlight the importance of astrocytes not only in housekeeping functions, but also in contributing to plasticity and information processing in the cerebellum.

  16. Cytotoxic CD8+ T cells and CD138+ plasma cells prevail in cerebrospinal fluid in non-paraneoplastic cerebellar ataxia with contactin-associated protein-2 antibodies

    Directory of Open Access Journals (Sweden)

    Melzer Nico

    2012-07-01

    Full Text Available Abstract Objective The purpose of this paper is to report a patient with otherwise unexplained cerebellar ataxia with serum antibodies against contactin-associated protein-2 (CASPR-2 and provide a detailed description of the composition of cellular infiltrates in the cerebrospinal fluid (CSF compared to the peripheral blood (PB. CASPR-2 antibodies strongly labeling axons of cerebellar granule neurons have recently been identified in sera from nine patients with otherwise unexplained progressive cerebellar ataxia with mild to severe cerebellar atrophy. Design This is a report of a single case. Methods The study methods used were neurologic examination, magnetic resonance imaging, fluorodeoxyglucose positron emisson tomography, lumbar puncture and multicolor flow-cytometry. Results A 23-year-old Caucasian male presented with a two-year history of a progressive cerebellar and brainstem syndrome. Magnetic resonance imaging (MRI showed pronounced cerebellar atrophy, especially of the medial parts of the hemispheres and the vermis. Cerebral fluorodeoxyglucose positron emission tomography (FDG-PET showed pronounced hypometabolism of the whole cerebellum. CASPR-2 antibodies were detected in the serum but not the CSF, and none of the staging and laboratory assessments revealed other causes of progressive cerebellar degeneration. Interestingly, flow-cytometry of the CSF as compared to the PB showed increased fractions of CD138+ plasma cells as well as human leukocyte antigen (HLA-DR+ CD8+ T cells suggesting that both B cells and CD8+ T cells were preferentially recruited to and activated within the CSF- (and putatively central nervous system (CNS- compartment. Conclusion We confirm the association of CASPR-2 serum antibodies with cerebellar ataxia and provide the first evidence for a combined humoral and cellular immune response in this novel antibody-associated inflammatory CNS disease.

  17. New supervised learning theory applied to cerebellar modeling for suppression of variability of saccade end points.

    Science.gov (United States)

    Fujita, Masahiko

    2013-06-01

    A new supervised learning theory is proposed for a hierarchical neural network with a single hidden layer of threshold units, which can approximate any continuous transformation, and applied to a cerebellar function to suppress the end-point variability of saccades. In motor systems, feedback control can reduce noise effects if the noise is added in a pathway from a motor center to a peripheral effector; however, it cannot reduce noise effects if the noise is generated in the motor center itself: a new control scheme is necessary for such noise. The cerebellar cortex is well known as a supervised learning system, and a novel theory of cerebellar cortical function developed in this study can explain the capability of the cerebellum to feedforwardly reduce noise effects, such as end-point variability of saccades. This theory assumes that a Golgi-granule cell system can encode the strength of a mossy fiber input as the state of neuronal activity of parallel fibers. By combining these parallel fiber signals with appropriate connection weights to produce a Purkinje cell output, an arbitrary continuous input-output relationship can be obtained. By incorporating such flexible computation and learning ability in a process of saccadic gain adaptation, a new control scheme in which the cerebellar cortex feedforwardly suppresses the end-point variability when it detects a variation in saccadic commands can be devised. Computer simulation confirmed the efficiency of such learning and showed a reduction in the variability of saccadic end points, similar to results obtained from experimental data.

  18. Properties of bilateral spinocerebellar activation of cerebellar cortical neurons

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    Pontus eGeborek

    2014-10-01

    Full Text Available We aimed to explore the cerebellar cortical inputs from two spinocerebellar pathways, the spinal border cell-component of the ventral spinocerebellar tract (SBC-VSCT and the dorsal spinocerebellar tract (DSCT, respectively, in the sublobule C1 of the cerebellar posterior lobe. The two pathways were activated by electrical stimulation of the contralateral lateral funiculus (coLF and the ipsilateral LF (iLF at lower thoracic levels. Most granule cells in sublobule C1 did not respond at all but part of the granule cell population displayed high-intensity responses to either coLF or iLF stimulation. As a rule, Golgi cells and Purkinje cell simple spikes responded to input from both LFs, although Golgi cells could be more selective. In addition, a small population of granule cells responded to input from both the coLF and the iLF. However, in these cases, similarities in the temporal topography and magnitude of the responses suggested that the same axons were stimulated from the two LFs, i.e. that the axons of individual spinocerebellar neurons could be present in both funiculi. This was also confirmed for a population of spinal neurons located within known locations of SBC-VSCT neurons and dorsal horn DSCT neurons. We conclude that bilateral spinocerebellar responses can occur in cerebellar granule cells, but the VSCT and DSCT systems that provide the input can also be organized bilaterally. The implications for the traditional functional separation of VSCT and DSCT systems and the issue whether granule cells primarily integrate functionally similar information or not are discussed.

  19. Probabilistic identification of cerebellar cortical neurones across species.

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    Gert Van Dijck

    Full Text Available Despite our fine-grain anatomical knowledge of the cerebellar cortex, electrophysiological studies of circuit information processing over the last fifty years have been hampered by the difficulty of reliably assigning signals to identified cell types. We approached this problem by assessing the spontaneous activity signatures of identified cerebellar cortical neurones. A range of statistics describing firing frequency and irregularity were then used, individually and in combination, to build Gaussian Process Classifiers (GPC leading to a probabilistic classification of each neurone type and the computation of equi-probable decision boundaries between cell classes. Firing frequency statistics were useful for separating Purkinje cells from granular layer units, whilst firing irregularity measures proved most useful for distinguishing cells within granular layer cell classes. Considered as single statistics, we achieved classification accuracies of 72.5% and 92.7% for granular layer and molecular layer units respectively. Combining statistics to form twin-variate GPC models substantially improved classification accuracies with the combination of mean spike frequency and log-interval entropy offering classification accuracies of 92.7% and 99.2% for our molecular and granular layer models, respectively. A cross-species comparison was performed, using data drawn from anaesthetised mice and decerebrate cats, where our models offered 80% and 100% classification accuracy. We then used our models to assess non-identified data from awake monkeys and rabbits in order to highlight subsets of neurones with the greatest degree of similarity to identified cell classes. In this way, our GPC-based approach for tentatively identifying neurones from their spontaneous activity signatures, in the absence of an established ground-truth, nonetheless affords the experimenter a statistically robust means of grouping cells with properties matching known cell classes. Our

  20. Stimulation of the N-methyl-D-aspartate receptor has a trophic effect on differentiating cerebellar granule cells

    DEFF Research Database (Denmark)

    Balázs, R; Hack, N; Jørgensen, Ole Steen

    1988-01-01

    N-methyl-D-aspartate (NMDA) supplementation of cerebellar cultures enriched in granule neurones (about 90%) prevented the extensive cell loss which occurs when cultivation takes place, in serum containing media, in the presence of 'low' K+ (5-15 mM). Estimation of tetanus toxin receptors and N-CA...

  1. Cerebellar LTD vs. motor learning-lessons learned from studying GluD2.

    Science.gov (United States)

    Yuzaki, Michisuke

    2013-11-01

    Synaptic plasticity, such as long-term potentiation and long-term depression (LTD), is believed to underlie learning and memory processes in vivo. The cerebellum is an ideal brain region to obtain definitive proof for this hypothesis. The current belief is that the acquisition of motor learning is stored by LTD at the parallel fiber (PF)-Purkinje cell synapse in the cerebellar cortex. Recently, however, several lines of mutant mice that display normal motor learning in the absence of cerebellar LTD have been reported. A similar dichotomy between synaptic plasticity at the circuitry level and learning at the behavioral level has also been reported in the hippocampus. One possible explanation for this dichotomy is that compensatory pathways at the molecular and circuitry levels play an important role in mice that have been genetically modified for their entire lives. Mice that are genetically modified to be deficient in or to express mutant versions of the δ2 glutamate receptor (GluD2) serve as an interesting model due to the predominant expression of GluD2 at PF-Purkinje cell synapses. Furthermore, two major functions of GluD2-PF synapse formation and LTD induction-can be mechanistically dissociated so that the role of LTD in motor learning can be investigated in the absence of morphological abnormalities caused by altered synapse formation. Therefore, genetic manipulations of GluD2 will help to clarify the relationship between LTD and motor learning in the cerebellum.

  2. Pathological changes in Purkinje cells of the cerebellum in acrylamide-intoxicated Ola mice and 6J mice%丙烯酰胺中毒Ola和6J鼠小脑Purkinje细胞的病理改变

    Institute of Scientific and Technical Information of China (English)

    赫秋月; 韩漫夫; 饶明俐

    2001-01-01

    Objective To observe the differential pathological changes in Purkinje cells of the cerebellum in Ola mice and 6J mice after acrylamide intoxication. Methods Purkinje cells were studied by light microscope and electron microscope. Results Under light microscope,Purkinje cells in 6J mice were densely stained and irregular in cell shape.Under electron microscope,parts of the plasma membrane projection containing some smooth tubular endoplasmic reticula were found occasionally,and the membrane became split and thickened.These abnormal changes were not found in Ola mice. Conclusion Acrylamide intoxication may induce pathological changes in Purkinje cells of 6J mice which may be the pathological basis of ataxia.%目的 观察丙烯酰胺(ACR)中毒后Ola和6J鼠小脑的不同病理改变。方法 采用病理学技术对小脑Purkinje细胞进行光镜和电镜定性分析。结果 光镜下小脑整个Purkinje细胞深染,形态不规则;电镜下偶见胞膜限局性膨出,内含一些管状滑面内质网,在突起的表面部分胞膜分层、变厚。上述改变仅见于6J鼠,而Ola鼠未见异常变化。结论 丙烯酰胺中毒导致6J鼠小脑Purkinje细胞病理改变,这种变化可能是产生共济失调的病理基础。

  3. The survival of cultured mouse cerebellar granule cells is not dependent on elevated potassium-ion concentration

    DEFF Research Database (Denmark)

    Mogensen, Helle Smidt; Hack, N; Balázs, R

    1994-01-01

    The effects of K(+)-induced membrane depolarization were studied on the survival and biochemical parameters in mouse and rat cerebellar granule cells grown in micro-well cultures. Cell numbers were determined by estimating DNA content using the Hoechst 33258 fluorochrome binding assay. DNA from d...... that although cultivation in 'high' K+ promotes biochemical differentiation in mouse cerebellar granule cells, these cells differ from their rat counterparts in that they do not develop a survival requirement for K(+)-induced membrane depolarization.......The effects of K(+)-induced membrane depolarization were studied on the survival and biochemical parameters in mouse and rat cerebellar granule cells grown in micro-well cultures. Cell numbers were determined by estimating DNA content using the Hoechst 33258 fluorochrome binding assay. DNA from...... degenerated cells was removed by prior DNAase treatment. These DNA estimates of cell numbers were comparable with values obtained by direct counting of fluorescein diacetate-stained viable cells. In agreement with previous studies, the survival of rat granule cells was promoted by increasing the concentration...

  4. Cell Division Mode Change Mediates the Regulation of Cerebellar Granule Neurogenesis Controlled by the Sonic Hedgehog Signaling

    OpenAIRE

    Rong Yang; Minglei Wang; Jia Wang; Xingxu Huang; Ru Yang; Wei-Qiang Gao

    2015-01-01

    Summary Symmetric and asymmetric divisions are important for self-renewal and differentiation of stem cells during neurogenesis. Although cerebellar granule neurogenesis is controlled by sonic hedgehog (SHH) signaling, whether and how this process is mediated by regulation of cell division modes have not been determined. Here, using time-lapse imaging and cell culture from neuronal progenitor-specific and differentiated neuron-specific reporter mouse lines (Math1-GFP and Dcx-DsRed) and Patche...

  5. Protective Effect of Edaravone in Primary Cerebellar Granule Neurons against Iodoacetic Acid-Induced Cell Injury

    Directory of Open Access Journals (Sweden)

    Xinhua Zhou

    2015-01-01

    Full Text Available Edaravone (EDA is clinically used for treatment of acute ischemic stroke in Japan and China due to its potent free radical-scavenging effect. However, it has yet to be determined whether EDA can attenuate iodoacetic acid- (IAA- induced neuronal death in vitro. In the present study, we investigated the effect of EDA on damage of IAA-induced primary cerebellar granule neurons (CGNs and its possible underlying mechanisms. We found that EDA attenuated IAA-induced cell injury in CGNs. Moreover, EDA significantly reduced intracellular reactive oxidative stress production, loss of mitochondrial membrane potential, and caspase 3 activity induced by IAA. Taken together, EDA protected CGNs against IAA-induced neuronal damage, which may be attributed to its antiapoptotic and antioxidative activities.

  6. Protective Effect of Edaravone in Primary Cerebellar Granule Neurons against Iodoacetic Acid-Induced Cell Injury

    Science.gov (United States)

    Zhou, Xinhua; Zhu, Longjun; Wang, Liang; Guo, Baojian; Zhang, Gaoxiao; Sun, Yewei; Zhang, Zaijun; Lee, Simon Ming-Yuen; Yu, Pei; Wang, Yuqiang

    2015-01-01

    Edaravone (EDA) is clinically used for treatment of acute ischemic stroke in Japan and China due to its potent free radical-scavenging effect. However, it has yet to be determined whether EDA can attenuate iodoacetic acid- (IAA-) induced neuronal death in vitro. In the present study, we investigated the effect of EDA on damage of IAA-induced primary cerebellar granule neurons (CGNs) and its possible underlying mechanisms. We found that EDA attenuated IAA-induced cell injury in CGNs. Moreover, EDA significantly reduced intracellular reactive oxidative stress production, loss of mitochondrial membrane potential, and caspase 3 activity induced by IAA. Taken together, EDA protected CGNs against IAA-induced neuronal damage, which may be attributed to its antiapoptotic and antioxidative activities. PMID:26557222

  7. Beta-amyloid overload does not directly correlate with SAPK/JNK activation and tau protein phosphorylation in the cerebellar cortex of Ts65Dn mice.

    Science.gov (United States)

    Lomoio, Selene; Scherini, Elda; Necchi, Daniela

    2009-11-10

    It is known that in the nervous tissue beta-amyloid overproduction and its extracellular or intracellular deposition can activate mitogen-activated protein kinases involved in tau protein phosphorylation. Hyperphosphorylated tau is not more able to bind neuron microtubules, leading to their disassembly and axon degeneration. We have previously described that at 10 months of age in the cerebellum of Ts65Dn mice, which are partially trisomic for the chromosome 16 and are considered a valuable model for Down syndrome, Purkinje cells undergo axon degeneration. Taking into consideration that Ts65Dn mice carry three copies of the gene encoding for the amyloid precursor protein, to characterize potential signaling events triggering the degenerative phenomenon, specific antibodies were used to examine the role of beta-amyloid overload in the activation of the stress activated kinase/c-jun N-terminal kinase (SAPK/JNK) and tau protein phosphorylation in the cerebellar cortex of 12-month-old Ts65Dn mice. We found small extracellular deposits of beta-amyloid at the borderline between the granule cell layer and the white matter, i.e., in the vicinity of the area where calbindin immunostaining of Purkinje cell axons revealed clusters of newly formed terminals of injured axons. Moreover, intracellular deposits were present in the somata of Purkinje cells. The level of activation of SAPK/JNK was greatly increased. The activation occurred in the "pinceaux" made by basket interneuron axons at the axon hillock of Purkinje cells. Antibody directed against tau protein phosphorylated at Ser-396/Ser-404 revealed positive NG2 cells and Bergman fibers in the molecular layer and oligodendrocytes in the white matter. Data indicate that beta-amyloid extracellular deposits could have exerted a local cytotoxic effect, leading to Purkinje cell axon degeneration. The activation of SAPK/JNK in basket cell "pinceaux" may be a consequence of altered functionality of Purkinje cells and may represent

  8. Effect of long-chain triglyceride lipid emulsion on bupivacaine-induced changes in electrophysiological parameters of rabbit Purkinje cells.

    Science.gov (United States)

    Lemoine, Sandrine; Rouet, René; Manrique, Alain; Hanouz, Jean-Luc

    2014-10-01

    Lipid emulsions are used in the reversal of local anesthetic toxicity. The aim of this study was to investigate the cellular electrophysiological effects of long-chain triglyceride lipid emulsion (LCTE) on cardiac action potential characteristics and conduction disturbances induced by bupivacaine. Purkinje fibers were dissected from the left ventricle of New Zealand white rabbit hearts and superfused with either Tyrode's solution during 30 min (control group), with bupivacaine 10(-6) M, 10(-5) M, and 5.10(-5) M alone, or in the presence of LCTE 0.5%, in addition, LCTE at 0.1%, 0.5%, and 1% was perfused alone. Electrophysiological parameters were recorded using the conventional microelectrode technique (37 °C, 1 Hz frequency). Bupivacaine 5.10(-5) M-induced conduction blocks (8/8 preparations): LCTE 0.5% suppressed the bupivacaine 5.10(-5) M-induced conduction blocks (1/8 preparations). Exposure to bupivacaine 10(-6) M, 10(-5) M, and 5.10(-5) M resulted in a significant decrease in the maximal rate of depolarization (Vmax) (respectively, 25%, 55%, 75%; P bupivacaine 10(-6) M did not significantly decreased Vmax (13%; P = 0.10 vs. control group). The decrease in Vmax resulting from bupivacaine 10(-5) M alone was significantly less in the presence of LCTE 0.5% (P bupivacaine 10(-5) M alone). Exposure to bupivacaine 10(-6) M, 10(-5) M, and 5.10(-5) M alone or in the presence of LCTE 0.5% resulted in a significant decrease in action potential duration measured at 50% and 90% repolarization (APD50 and APD90; P bupivacaine. Moreover, LCTE 0.5% attenuates the decrease in Vmax induced by bupivacaine 10(-6) M and 10(-5) M.

  9. GABA agonist promoted formation of low affinity GABA receptors on cerebellar granule cells is restricted to early development

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, G H; Schousboe, A;

    1988-01-01

    The ability of the GABA receptor agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP) to promote formation of low affinity GABA receptors on cerebellar granule cells was tested using primary cultures of these neurons. Granule cells were exposed to THIP (150 microM) for 6 hr after......, respectively, 4, 7, 10 and 14 days in culture. It was found that THIP treatment of 4- and 7-day-old cultures led to formation of low affinity GABA receptors, whereas such receptors could not be detected after THIP treatment in the older cultures (10 and 14 days) in spite of the fact that these cultured granule...... cells expressed a high density of high affinity GABA receptors. It is concluded that the ability of THIP to promote formation of low affinity GABA receptors on cerebellar granule cells is restricted to an early developmental period....

  10. Mice lacking the transcription factor SHOX2 display impaired cerebellar development and deficits in motor coordination.

    Science.gov (United States)

    Rosin, Jessica M; McAllister, Brendan B; Dyck, Richard H; Percival, Christopher J; Kurrasch, Deborah M; Cobb, John

    2015-03-01

    Purkinje cells of the developing cerebellum secrete the morphogen sonic hedgehog (SHH), which is required to maintain the proliferative state of granule cell precursors (GCPs) prior to their differentiation and migration to form the internal granule layer (IGL). Despite a wealth of knowledge regarding the function of SHH during cerebellar development, the upstream regulators of Shh expression during this process remain largely unknown. Here we report that the murine short stature homeobox 2 (Shox2) gene is required for normal Shh expression in dorsal-residing Purkinje cells. Using two different Cre drivers, we show that elimination of Shox2 in the brain results in developmental defects in the inferior colliculus and cerebellum. Specifically, loss of Shox2 in the cerebellum results in precocious differentiation and migration of GCPs from the external granule layer (EGL) to the IGL. This correlates with premature bone morphogenetic protein 4 (Bmp4) expression in granule cells of the dorsal cerebellum. The size of the neonatal cerebellum is reduced in Shox2-mutant animals, which is consistent with a reduction in the number of GCPs present in the EGL, and could account for the smaller vermis and thinner IGL present in adult Shox2mutants. Shox2-mutant mice also display reduced exploratory activity, altered gait and impaired motor coordination. Our findings are the first to show a role for Shox2 in brain development. We provide evidence that Shox2 plays an important role during cerebellar development, perhaps to maintain the proper balance of Shh and Bmp expression levels in the dorsal vermis, and demonstrate that in the absence of Shox2, mice display both cerebellar impairments and deficits in motor coordination, ultimately highlighting the importance of Shox2 in the cerebellum.

  11. Proneurotrophin-3 promotes cell cycle withdrawal of developing cerebellar granule cell progenitors via the p75 neurotrophin receptor.

    Science.gov (United States)

    Zanin, Juan Pablo; Abercrombie, Elizabeth; Friedman, Wilma J

    2016-07-19

    Cerebellar granule cell progenitors (GCP) proliferate extensively in the external granule layer (EGL) of the developing cerebellum prior to differentiating and migrating. Mechanisms that regulate the appropriate timing of cell cycle withdrawal of these neuronal progenitors during brain development are not well defined. The p75 neurotrophin receptor (p75(NTR)) is highly expressed in the proliferating GCPs, but is downregulated once the cells leave the cell cycle. This receptor has primarily been characterized as a death receptor for its ability to induce neuronal apoptosis following injury. Here we demonstrate a novel function for p75(NTR) in regulating proper cell cycle exit of neuronal progenitors in the developing rat and mouse EGL, which is stimulated by proNT3. In the absence of p75(NTR), GCPs continue to proliferate beyond their normal period, resulting in a larger cerebellum that persists into adulthood, with consequent motor deficits.

  12. Melatonin protects rat cerebellar granule cells against electromagnetic field-induced increases in Na(+) currents through intracellular Ca(2+) release.

    Science.gov (United States)

    Liu, Dong-Dong; Ren, Zhen; Yang, Guang; Zhao, Qian-Ru; Mei, Yan-Ai

    2014-06-01

    Although melatonin (MT) has been reported to protect cells against oxidative damage induced by electromagnetic radiation, few reports have addressed whether there are other protective mechanisms. Here, we investigated the effects of MT on extremely low-frequency electromagnetic field (ELF-EMF)-induced Nav activity in rat cerebellar granule cells (GCs). Exposing cerebellar GCs to ELF-EMF for 60 min. significantly increased the Nav current (INa ) densities by 62.5%. MT (5 μM) inhibited the ELF-EMF-induced INa increase. This inhibitory effect of MT is mimicked by an MT2 receptor agonist and was eliminated by an MT2 receptor antagonist. The Nav channel steady-state activation curve was significantly shifted towards hyperpolarization by ELF-EMF stimulation but remained unchanged by MT in cerebellar GC that were either exposed or not exposed to ELF-EMF. ELF-EMF exposure significantly increased the intracellular levels of phosphorylated PKA in cerebellar GCs, and both MT and IIK-7 did not reduce the ELF-EMF-induced increase in phosphorylated PKA. The inhibitory effects of MT on ELF-EMF-induced Nav activity was greatly reduced by the calmodulin inhibitor KN93. Calcium imaging showed that MT did not increase the basal intracellular Ca(2+) level, but it significantly elevated the intracellular Ca(2+) level evoked by the high K(+) stimulation in cerebellar GC that were either exposed or not exposed to ELF-EMF. In the presence of ruthenium red, a ryanodine-sensitive receptor blocker, the MT-induced increase in intracellular calcium levels was reduced. Our data show for the first time that MT protects against neuronal INa that result from ELF-EMF exposure through Ca(2+) influx-induced Ca(2+) release.

  13. Intrinsic properties and mechanisms of spontaneous firing in mouse cerebellar unipolar brush cells.

    Science.gov (United States)

    Russo, Marco J; Mugnaini, Enrico; Martina, Marco

    2007-06-01

    Neuronal firing patterns are determined by the cell's intrinsic electrical and morphological properties and are regulated by synaptic interactions. While the properties of cerebellar neurons have generally been studied in much detail, little is known about the unipolar brush cells (UBCs), a type of glutamatergic interneuron that is enriched in the granular layer of the mammalian vestibulocerebellum and participates in the representation of head orientation in space. Here we show that UBCs can be distinguished from adjacent granule cells on the basis of differences in membrane capacitance, input resistance and response to hyperpolarizing current injection. We also show that UBCs are intrinsically firing neurons. Using action potential clamp experiments and whole-cell recordings we demonstrate that two currents contribute to this property: a persistent TTX-sensitive sodium current and a ruthenium red-sensitive, TRP-like cationic current, both of which are active during interspike intervals and have reversal potentials positive to threshold. Interestingly, although UBCs are also endowed with a large I(h) current, this current is not involved in their intrinsic firing, perhaps because it activates at voltages that are more hyperpolarized than those associated with autonomous activity.

  14. Dynamic changes of [Ca2+]i in cerebellar granule cells exposed to pulsed electric fields

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Intracellular free Ca2+ concentration ([Ca2+]i) in embryonic chick cerebellar granule cells loaded with fluo-3/AM and exposed to a single pulsed electric field was investigated using a confocal laser scanning microscope and fluorescent microscope equipped with CCD video imaging system.The results showed that [Ca2+]i increased immediately and rose to the peak rapidly as the cells exposed to a single pulsed electric field.The amplitude and rate of the increases of [Ca2+]i depend on the intensity of external electric field.In the presence of Ca2+ chelant EGTA or Ca2+ channels blocker La3+ in the pulsation solutions,the increase of [Ca2+]i was still observable.It was also observed that [Ca2+]i of different intracellular areas in the cell elevated simultaneously while the peak of the increase of [Ca2+]i in the poles of the cell preceded to the peak in its somata and recovered to a plateau within a short time.

  15. Dynamic changes of [Ca2+]i in cerebellar granule cells exposed to pulsed electric fields

    Institute of Scientific and Technical Information of China (English)

    陈雅; 王彦; 孙彤; 张锦珠; 景向红; 李瑞午

    2000-01-01

    Intracellular free Ca2+ concentration ([Ca2+]i) in embryonic chick cerebellar granule cells loaded with fluo-3/AM and exposed to a single pulsed electric field was investigated using a confocal laser scanning microscope and fluorescent microscope equipped with CCD video imaging system. The results showed that [Ca2+]i increased immediately and rose to the peak rapidly as the cells exposed to a single pulsed electric field. The amplitude and rate of the increases of [Ca2+]i depend on the intensity of external electric field. In the presence of Ca2+ chelant EGTA or Ca2+ channels blocker La3+ in the pulsation solutions, the increase of [Ca2+]i was still observable. It was also observed that [Ca2+]i of different intracellular areas in the cell elevated simultaneously while the peak of the increase of [Ca2+]i in the poles of the cell preceded to the peak in its somata and recovered to a plateau within a short time.

  16. Motor learning in common marmosets: vestibulo-ocular reflex adaptation and its sensitivity to inhibitors of Purkinje cell long-term depression.

    Science.gov (United States)

    Anzai, Mari; Nagao, Soich

    2014-06-01

    Adaptation of the horizontal vestibulo-ocular reflex (HVOR) provides an experimental model for cerebellum-dependent motor learning. We developed an eye movement measuring system and a paradigm for induction of HVOR adaptation for the common marmoset. The HVOR gain in dark measured by 10° (peak-to-peak amplitude) and 0.11-0.5Hz turntable oscillation was around unity. The gain-up and gain-down HVOR adaptation was induced by 1h of sustained out-of-phase and in-phase 10°-0.33Hz combined turntable-screen oscillation in the light, respectively. To examine the role of long-term depression (LTD) of parallel fiber-Purkinje cell synapses, we intraperitonially applied T-588 or nimesulide, which block the induction of LTD in vitro or in vivo preparations, 1h before the test of HVOR adaptation. T-588 (3 and 5mg/kg body weight) did not affect nonadapted HVOR gains, and impaired both gain-up and gain-down HVOR adaptation. Nimesulide (3 and 6mg/kg) did not affect nonadapted HVOR gains, and impaired gain-up HVOR adaptation dose-dependently; however, it very little affected gain-down HVOR adaptation. These findings are consistent with the results of our study of nimesulide on the adaptation of horizontal optokinetic response in mice (Le et al., 2010), and support the view that LTD underlies HVOR adaptation.

  17. [Paraneoplastic cerebellar degeneration associated with ovarian cancer: anti-Yo immunoreactivity in autoptic cerebellum and ovarian carcinoma].

    Science.gov (United States)

    Bartos, A; Stourac, P; Rusina, R; Sejdová, M; Velenská, Z

    2002-10-01

    Paraneoplastic cerebellar degeneration is a rare disorder caused likely by autoimmune mechanisms in malignant oncologic diseases, and the most common tumors are ovarian, breast, lung cancer, and m. Hodgkin. An immune reaction is supposed to be directed against identical antigens of cerebellum and tumor, and paraneoplastic antibodies called anti-Yo, anti-Hu, anti-Ri, or anti-Tr are often detected in blood and cerebrospinal fluid. The course of paraneoplastic cerebellar degeneration as a complication of ovarian cancer is described. The relationship between the malignancy and pathologic changes in cerebellum was confirmed by positive immunohistochemical and immunofluorescence reaction between a patient's anti-Yo-positive serum and her own Purkinje's and ovarian cancer cells.

  18. Development of the cerebellar body in sharks: spatiotemporal relations of Pax6 expression, cell proliferation and differentiation.

    Science.gov (United States)

    Rodríguez-Moldes, Isabel; Ferreiro-Galve, Susana; Carrera, Iván; Sueiro, Catalina; Candal, Eva; Mazan, Sylvie; Anadón, Ramón

    2008-02-20

    We have studied the patterns of cell proliferation, regional organization and differentiation in the cerebellar body of embryos and juveniles of two shark species by immunohistochemistry with antibodies against proliferating cell nuclear antigen (PCNA), Pax6, reelin (RELN), GABA, glutamic acid decarboxylase (GAD) and calretinin (CR). The organization of Pax6-expressing cells was also studied by in situ hybridization. Our results reveal that a transient secondary matrix zone, the external germinal layer, is formed in sharks at early stages of cerebellar development and is the source of the earliest Pax6-expressing (granule) cells. Later in development, new granule Pax6-expressing cells arise from medial proliferation zones and accumulate medially in the granular eminences. The GABAergic components appear very early, and show clear regional differences. The medial proliferation zones remain active even in adults. Taken together, the proliferation and differentiation markers used in the present study highlight striking similarities during development between the cerebellar body of elasmobranchs and the cerebella of tetrapods. These results show the importance of elasmobranch models to reconstruct the evolutionary developmental history of the vertebrate cerebellum.

  19. Computation of inverse functions in a model of cerebellar and reflex pathways allows to control a mobile mechanical segment.

    Science.gov (United States)

    Ebadzadeh, M; Tondu, B; Darlot, C

    2005-01-01

    The command and control of limb movements by the cerebellar and reflex pathways are modeled by means of a circuit whose structure is deduced from functional constraints. One constraint is that fast limb movements must be accurate although they cannot be continuously controlled in closed loop by use of sensory signals. Thus, the pathways which process the motor orders must contain approximate inverse functions of the bio-mechanical functions of the limb and of the muscles. This can be achieved by means of parallel feedback loops, whose pattern turns out to be comparable to the anatomy of the cerebellar pathways. They contain neural networks able to anticipate the motor consequences of the motor orders, modeled by artificial neural networks whose connectivity is similar to that of the cerebellar cortex. These networks learn the direct biomechanical functions of the limbs and muscles by means of a supervised learning process. Teaching signals calculated from motor errors are sent to the learning sites, as, in the cerebellum, complex spikes issued from the inferior olive are conveyed to the Purkinje cells by climbing fibers. Learning rules are deduced by a differential calculation, as classical gradient rules, and they account for the long term depression which takes place in the dendritic arborizations of the Purkinje cells. Another constraint is that reflexes must not impede voluntary movements while remaining at any instant ready to oppose perturbations. Therefore, efferent copies of the motor orders are sent to the interneurones of the reflexes, where they cancel the sensory-motor consequences of the voluntary movements. After learning, the model is able to drive accurately, both in velocity and position, angular movements of a rod actuated by two pneumatic McKibben muscles. Reflexes comparable to the myotatic and tendinous reflexes, and stabilizing reactions comparable to the cerebellar sensory-motor reactions, reduce efficiently the effects of perturbing torques

  20. Computational reconstruction of pacemaking and intrinsic electroresponsiveness in cerebellar golgi cells

    Directory of Open Access Journals (Sweden)

    Sergio Solinas

    2007-12-01

    Full Text Available The Golgi cells have been recently shown to beat regularly in vitro (Forti et al., 2006. J. Physiol. 574, 711-729. Four main currents were shown to be involved, namely a persistent sodium current (INa-p, an h current (Ih, an SK-type calcium-dependent potassium current (IK-AHP, and a slow M-like potassium current (IK-slow. These ionic currents could take part, together with others, also to different aspects of neuronal excitability like responses to depolarizing and hyperpolarizing current injection. However, the ionic mechanisms and their interactions remained largely hypothetical. In this work, we have investigated the mechanisms of Golgi cell excitability by developing a computational model. The model predicts that pacemaking is sustained by subthreshold oscillations tightly coupled to spikes. INa-p and IK-slow emerged as the critical determinants of oscillations. Ih also played a role by setting the oscillatory mechanism into the appropriate membrane potential range. IK-AHP, though taking part to the oscillation, appeared primarily involved in regulating the ISI following spikes. The combination with other currents, in particular a resurgent sodium current (INa-r and an A-current (IK-A, allowed a precise regulation of response frequency and delay. These results provide a coherent reconstruction of the ionic mechanisms determining Golgi cell intrinsic electroresponsiveness and suggests important implications for cerebellar signal processing, which will be fully developed in a companion paper (Solinas et al., 2008. Front. Neurosci. 1:4.

  1. Developmental features of rat cerebellar neural cells cultured in a chemically defined medium

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, V.; Ciotti, M.T.; Aloisi, F.; Levi, G.

    1986-01-01

    We studied some aspects of the differentiation of rat cerebellar neural cells obtained from 8-day postnatal animals and cultured in a serum-free, chemically defined medium (CDM). The ability of the cells to take up radioactive transmitter amino acids was analyzed autoradiographically. The L-glutamate analogue /sup 3/H-D-aspartate was taken up by astroglial cells, but not by granule neurons, even in late cultures (20 days in vitro). This is in agreement with the lack of depolarization-induced release of /sup 3/H-D-aspartate previously observed in this type of culture. In contrast, /sup 3/H-(GABA) was scarcely accumulated by glial-fibrillary-acidic-protein (GFAP)-positive astrocytes, but taken up by glutamate-decarboxylase-positive inhibitory interneurons and was released in a Ca2+-dependent way upon depolarization: /sup 3/H-GABA evoked release progressively increased with time in culture. Interestingly, the expression of the vesicle-associated protein synapsin I was much reduced in granule cells cultured in CDM as compared to those maintained in the presence of serum. These data would indicate that in CDM the differentiation of granule neurons is not complete, while that of GABAergic neurons is not greatly affected. Whether the diminished differentiation of granule cells must be attributed only to serum deprivation or also to other differences in the composition of the culture medium remains to be established. /sup 3/H-GABA was avidly taken up also by a population of cells which were not recognized by antibodies raised against GFAP, glutamate decarboxylase, and microtubule-associated protein 2. These cells have been characterized as bipotential precursors of oligodendrocytes and of a subpopulation of astrocytes bearing a stellate shape and capable of high-affinity /sup 3/H-GABA uptake.

  2. Expression of NR2B in cerebellar granule cells specifically facilitates effect of motor training on motor learning.

    Science.gov (United States)

    Jiao, Jianwei; Nakajima, Akira; Janssen, William G M; Bindokas, Vytautas P; Xiong, Xiaoli; Morrison, John H; Brorson, James R; Tang, Ya-Ping

    2008-02-27

    It is believed that gene/environment interaction (GEI) plays a pivotal role in the development of motor skills, which are acquired via practicing or motor training. However, the underlying molecular/neuronal mechanisms are still unclear. Here, we reported that the expression of NR2B, a subunit of NMDA receptors, in cerebellar granule cells specifically enhanced the effect of voluntary motor training on motor learning in the mouse. Moreover, this effect was characterized as motor learning-specific and developmental stage-dependent, because neither emotional/spatial memory was affected nor was the enhanced motor learning observed when the motor training was conducted starting at the age of 3 months old in these transgenic mice. These results indicate that changes in the expression of gene(s) that are involved in regulating synaptic plasticity in cerebellar granule cells may constitute a molecular basis for the cerebellum to be involved in the GEI by facilitating motor skill learning.

  3. Expression of NR2B in cerebellar granule cells specifically facilitates effect of motor training on motor learning.

    Directory of Open Access Journals (Sweden)

    Jianwei Jiao

    Full Text Available It is believed that gene/environment interaction (GEI plays a pivotal role in the development of motor skills, which are acquired via practicing or motor training. However, the underlying molecular/neuronal mechanisms are still unclear. Here, we reported that the expression of NR2B, a subunit of NMDA receptors, in cerebellar granule cells specifically enhanced the effect of voluntary motor training on motor learning in the mouse. Moreover, this effect was characterized as motor learning-specific and developmental stage-dependent, because neither emotional/spatial memory was affected nor was the enhanced motor learning observed when the motor training was conducted starting at the age of 3 months old in these transgenic mice. These results indicate that changes in the expression of gene(s that are involved in regulating synaptic plasticity in cerebellar granule cells may constitute a molecular basis for the cerebellum to be involved in the GEI by facilitating motor skill learning.

  4. Forward transport of proteins in the plasma membrane of migrating cerebellar granule cells.

    Science.gov (United States)

    Wang, Dong; She, Liang; Sui, Ya-nan; Yuan, Xiao-bing; Wen, Yunqing; Poo, Mu-ming

    2012-12-18

    Directional flow of membrane components has been detected at the leading front of fibroblasts and the growth cone of neuronal processes, but whether there exists global directional flow of plasma membrane components over the entire migrating neuron remains largely unknown. By analyzing the trajectories of antibody-coated single quantum dots (QDs) bound to two membrane proteins, overexpressed myc-tagged synaptic vesicle-associated membrane protein VAMP2 and endogenous neurotrophin receptor TrkB, we found that these two proteins exhibited net forward transport, which is superimposed upon Brownian motion, in both leading and trailing processes of migrating cerebellar granule cells in culture. Furthermore, no net directional transport of membrane proteins was observed in nonmigrating cells with either growing or stalling leading processes. Analysis of the correlation of motion direction between two QDs on the same process in migrating neurons also showed a higher frequency of correlated forward than rearward movements. Such correlated QD movements were markedly reduced in the presence of myosin II inhibitor blebbistatin,suggesting the involvement of myosin II-dependent active transport processes. Thus, a net forward transport of plasma membrane proteins exists in the leading and trailing processes of migrating neurons, in line with the translocation of the soma.

  5. Electrophysiological mapping of novel prefrontal - cerebellar pathways

    Directory of Open Access Journals (Sweden)

    Thomas C Watson

    2009-08-01

    Full Text Available Whilst the cerebellum is predominantly considered a sensorimotor control structure, accumulating evidence suggests that it may also subserve non motor functions during cognition. However, this possibility is not universally accepted, not least because the nature and pattern of links between higher cortical structures and the cerebellum are poorly characterized. We have therefore used in vivo electrophysiological methods in anaesthetized rats to directly investigate connectivity between the medial prefrontal cortex (prelimbic subdivision, PrL and the cerebellum. Stimulation of deep layers of PrL evoked distinct field potentials in the cerebellar cortex with a mean latency to peak of approximately 35ms. These responses showed a well-defined topography, and were maximal in lobule VII of the contralateral vermis (a known oculomotor centre; they were not attenuated by local anesthesia of the overlying M2 motor cortex, though M2 stimulation did evoke field potentials in lobule VII with a shorter latency. Single-unit recordings showed that prelimbic cortical stimulation elicits complex spikes in lobule VII Purkinje cells, indicating transmission via a previously undescribed cerebro-olivocerebellar pathway. Our results therefore establish a physiological basis for communication between PrL and the cerebellum. The role(s of this pathway remain to be resolved, but presumably relate to control of eye movements and/or distributed networks associated with integrated prefrontal cortical functions.

  6. Acute cerebellar ataxia

    Science.gov (United States)

    Cerebellar ataxia; Ataxia - acute cerebellar; Cerebellitis; Post-varicella acute cerebellar ataxia; PVACA ... Acute cerebellar ataxia in children, especially younger than age 3, may occur several weeks after an illness caused by a virus. ...

  7. The Gs-linked receptor GPR3 inhibits the proliferation of cerebellar granule cells during postnatal development.

    Directory of Open Access Journals (Sweden)

    Shigeru Tanaka

    Full Text Available BACKGROUND: During postnatal murine and rodent cerebellar development, cerebellar granule precursors (CGP gradually stop proliferating as they differentiate after migration to the internal granule layer (IGL. Molecular events that govern this program remain to be fully elucidated. GPR3 belongs to a family of Gs-linked receptors that activate cyclic AMP and are abundantly expressed in the adult brain. METHODOLOGY/PRINCIPAL FINDINGS: To investigate the role of this orphan receptor in CGP differentiation, we determined that exogenous GPR3 expression in rat cerebellar granule neurons partially antagonized the proliferative effect of Sonic hedgehog (Shh, while endogenous GPR3 inhibition by siRNA stimulated Shh-induced CGP proliferation. In addition, exogenous GPR3 expression in CGPs correlated with increased p27/kip expression, while GPR3 knock-down led to a decrease in p27/kip expression. In wild-type mice, GPR3 expression increased postnatally and its expression was concentrated in the internal granular layer (IGL. In GPR3 -/- mice, the IGL was widened with increased proliferation of CGPs, as measured by bromodeoxyuridine incorporation. Cell cycle kinetics of GPR3-transfected medulloblastoma cells revealed a G0/G1 block, consistent with cell cycle exit. CONCLUSIONS/SIGNIFICANCE: These results thus indicate that GPR3 is a novel antiproliferative mediator of CGPs in the postnatal development of murine cerebellum.

  8. Densità e distribuzione delle cellule di Purkinje nel cervelletto di cane: studio immunoistochimico

    OpenAIRE

    Ruffini, Alessia

    2016-01-01

    Nella letteratura, gli studi morfologici e morfometrici del cervelletto di animali ed esseri umani, hanno valutato il numero di cellule di Purkinje (CP) solo su alcuni campi a random. Gli studi sono stati spesso condotti su cervelletti fissati in formalina e inclusi in paraffina; gli studi effettuati su campioni congelati sono molto rari. Gli scopi del presente studio sono stati: quantificare il numero e la distribuzione delle CP in tutto il tessuto cerebellare; valutare lo spessore del gr...

  9. Constitutive Intracellular Na+ Excess in Purkinje Cells Promotes Arrhythmogenesis at Lower Levels of Stress Than Ventricular Myocytes From Mice With Catecholaminergic Polymorphic Ventricular Tachycardia

    Science.gov (United States)

    Willis, B. Cicero; Pandit, Sandeep V.; Ponce-Balbuena, Daniela; Zarzoso, Manuel; Guerrero-Serna, Guadalupe; Limbu, Bijay; Deo, Makarand; Camors, Emmanuel; Ramirez, Rafael J.; Mironov, Sergey; Herron, Todd J.; Valdivia, Héctor H.

    2016-01-01

    Background— In catecholaminergic polymorphic ventricular tachycardia (CPVT), cardiac Purkinje cells (PCs) appear more susceptible to Ca2+ dysfunction than ventricular myocytes (VMs). The underlying mechanisms remain unknown. Using a CPVT mouse (RyR2R4496C+/Cx40eGFP), we tested whether PC intracellular Ca2+ ([Ca2+]i) dysregulation results from a constitutive [Na+]i surplus relative to VMs. Methods and Results— Simultaneous optical mapping of voltage and [Ca2+]i in CPVT hearts showed that spontaneous Ca2+ release preceded pacing-induced triggered activity at subendocardial PCs. On simultaneous current-clamp and Ca2+ imaging, early and delayed afterdepolarizations trailed spontaneous Ca2+ release and were more frequent in CPVT PCs than CPVT VMs. As a result of increased activity of mutant ryanodine receptor type 2 channels, sarcoplasmic reticulum Ca2+ load, measured by caffeine-induced Ca2+ transients, was lower in CPVT VMs and PCs than respective controls, and sarcoplasmic reticulum fractional release was greater in both CPVT PCs and VMs than respective controls. [Na+]i was higher in both control and CPVT PCs than VMs, whereas the density of the Na+/Ca2+ exchanger current was not different between PCs and VMs. Computer simulations using a PC model predicted that the elevated [Na+]i of PCs promoted delayed afterdepolarizations, which were always preceded by spontaneous Ca2+ release events from hyperactive ryanodine receptor type 2 channels. Increasing [Na+]i monotonically increased delayed afterdepolarization frequency. Confocal imaging experiments showed that postpacing Ca2+ spark frequency was highest in intact CPVT PCs, but such differences were reversed on saponin-induced membrane permeabilization, indicating that differences in [Na+]i played a central role. Conclusions— In CPVT mice, the constitutive [Na+]i excess of PCs promotes triggered activity and arrhythmogenesis at lower levels of stress than VMs. PMID:27169737

  10. Computational reconstruction of pacemaking and intrinsic electroresponsiveness in cerebellar Golgi cells.

    Science.gov (United States)

    Solinas, Sergio; Forti, Lia; Cesana, Elisabetta; Mapelli, Jonathan; De Schutter, Erik; D'Angelo, Egidio

    2007-01-01

    The Golgi cells have been recently shown to beat regularly in vitro (Forti et al., 2006. J. Physiol. 574, 711-729). Four main currents were shown to be involved, namely a persistent sodium current (I(Na-p)), an h current (I(h)), an SK-type calcium-dependent potassium current (I(K-AHP)), and a slow M-like potassium current (I(K-slow)). These ionic currents could take part, together with others, also to different aspects of neuronal excitability like responses to depolarizing and hyperpolarizing current injection. However, the ionic mechanisms and their interactions remained largely hypothetical. In this work, we have investigated the mechanisms of Golgi cell excitability by developing a computational model. The model predicts that pacemaking is sustained by subthreshold oscillations tightly coupled to spikes. I(Na-p) and I(K-slow) emerged as the critical determinants of oscillations. I(h) also played a role by setting the oscillatory mechanism into the appropriate membrane potential range. I(K-AHP), though taking part to the oscillation, appeared primarily involved in regulating the ISI following spikes. The combination with other currents, in particular a resurgent sodium current (I(Na-r)) and an A-current (I(K-A)), allowed a precise regulation of response frequency and delay. These results provide a coherent reconstruction of the ionic mechanisms determining Golgi cell intrinsic electroresponsiveness and suggests important implications for cerebellar signal processing, which will be fully developed in a companion paper (Solinas et al., 2008. Front. Neurosci. 2:4).

  11. NF1 regulation of RAS/ERK signaling is required for appropriate granule neuron progenitor expansion and migration in cerebellar development.

    Science.gov (United States)

    Sanchez-Ortiz, Efrain; Cho, Woosung; Nazarenko, Inga; Mo, Wei; Chen, Jian; Parada, Luis F

    2014-11-01

    Cerebellar development is regulated by a coordinated spatiotemporal interplay between granule neuron progenitors (GNPs), Purkinje neurons, and glia. Abnormal development can trigger motor deficits, and more recent data indicate important roles in aspects of memory, behavior, and autism spectrum disorders (ASDs). Germline mutation in the NF1 tumor suppressor gene underlies Neurofibromatosis type 1, a complex disease that enhances susceptibility to certain cancers and neurological disorders, including intellectual deficits and ASD. The NF1 gene encodes for neurofibromin, a RAS GTPase-activating protein, and thus negatively regulates the RAS signaling pathway. Here, using mouse models to direct conditional NF1 ablation in either embryonic cerebellar progenitors or neonatal GNPs, we show that neurofibromin is required for appropriate development of cerebellar folia layering and structure. Remarkably, neonatal administration of inhibitors of the ERK pathway reversed the morphological defects. Thus, our findings establish a critical cell-autonomous role for the NF1-RAS-ERK pathway in the appropriate regulation of cerebellar development and provide a basis for using neonatal ERK inhibitor-based therapies to treat NF1-induced cerebellar disorders.

  12. A Comparison on Stain of Purkinje Cell in Cerebellum by Two Different Methods%两种染色方法对小脑浦肯野细胞显示效果的比较

    Institute of Scientific and Technical Information of China (English)

    邵康; 张长征; 陈肖肖

    2007-01-01

    用常规Nissl染色和成年动物Golgi染色方法分别标记小脑浦肯野细胞(Purkinje cell,PC),比较其染色效果,结果显示,常规Nissl染色只能观察到PC胞体,胞体内的胞核及核仁也清晰可见,但树突和轴突不着色;成年动物Golgi染色能清晰地显示PC树突、轴突及树突棘的形态结构,但胞体结构不清楚.

  13. Cerebellar nuclei neurons show only small excitatory responses to optogenetic olivary stimulation in transgenic mice: in vivo and in vitro studies

    Directory of Open Access Journals (Sweden)

    Huo eLu

    2016-03-01

    Full Text Available To study the olivary input to the cerebellar nuclei (CN we used optogenetic stimulation in transgenic mice expressing channelrhodopsin-2 (ChR2 in olivary neurons. We obtained in vivo extracellular Purkinje cell (PC and CN recordings in anesthetized mice while stimulating the contralateral inferior olive (IO with a blue laser (single pulse, 10 - 50 ms duration. Peri-stimulus histograms were constructed to show the spike rate changes after optical stimulation. Among 29 CN neurons recorded, 15 showed a decrease in spike rate of variable strength and duration, and only 1 showed a transient spiking response. These results suggest that direct olivary input to CN neurons is usually overridden by stronger Purkinje cell inhibition triggered by climbing fiber responses. To further investigate the direct input from the climbing fiber collaterals we also conducted whole cell recordings in brain slices, where we used local stimulation with blue light. Due to the expression of ChR2 in Purkinje cell axons as well as the IO in our transgenic line, strong inhibitory responses could be readily triggered with optical stimulation (13 of 15 neurons. After blocking this inhibition with GABAzine, only in 5 of 13 CN neurons weak excitatory responses were revealed. Therefore our in vitro results support the in vivo findings that the excitatory input to CN neurons from climbing fiber collaterals in adult mice is masked by the inhibition under normal conditions.

  14. Cell Division Mode Change Mediates the Regulation of Cerebellar Granule Neurogenesis Controlled by the Sonic Hedgehog Signaling

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    Rong Yang

    2015-11-01

    Full Text Available Symmetric and asymmetric divisions are important for self-renewal and differentiation of stem cells during neurogenesis. Although cerebellar granule neurogenesis is controlled by sonic hedgehog (SHH signaling, whether and how this process is mediated by regulation of cell division modes have not been determined. Here, using time-lapse imaging and cell culture from neuronal progenitor-specific and differentiated neuron-specific reporter mouse lines (Math1-GFP and Dcx-DsRed and Patched+/− mice in which SHH signaling is activated, we find evidence for the existence of symmetric and asymmetric divisions that are closely associated with progenitor proliferation and differentiation. While activation of the SHH pathway enhances symmetric progenitor cell divisions, blockade of the SHH pathway reverses the cell division mode change in Math1-GFP;Dcx-DsRed;Patched+/− mice by promoting asymmetric divisions or terminal neuronal symmetric divisions. Thus, cell division mode change mediates the regulation of cerebellar granule neurogenesis controlled by SHH signaling.

  15. The brain-specific RasGEF very-KIND is required for normal dendritic growth in cerebellar granule cells and proper motor coordination

    Science.gov (United States)

    Hayashi, Kanehiro; Furuya, Asako; Sakamaki, Yuriko; Akagi, Takumi; Shinoda, Yo; Sadakata, Tetsushi; Hashikawa, Tsutomu; Shimizu, Kazuki; Minami, Haruka; Sano, Yoshitake; Nakayama, Manabu

    2017-01-01

    Very-KIND/Kndc1/KIAA1768 (v-KIND) is a brain-specific Ras guanine nucleotide exchange factor carrying two sets of the kinase non-catalytic C-lobe domain (KIND), and is predominantly expressed in cerebellar granule cells. Here, we report the impact of v-KIND deficiency on dendritic and synaptic growth in cerebellar granule cells in v-KIND knockout (KO) mice. Furthermore, we evaluate motor function in these animals. The gross anatomy of the cerebellum, including the cerebellar lobules, layered cerebellar cortex and densely-packed granule cell layer, in KO mice appeared normal, and was similar to wild-type (WT) mice. However, KO mice displayed an overgrowth of cerebellar granule cell dendrites, compared with WT mice, resulting in an increased number of dendrites, dendritic branches and terminals. Immunoreactivity for vGluT2 (a marker for excitatory presynapses of mossy fiber terminals) was increased in the cerebellar glomeruli of KO mice, compared with WT mice. The postsynaptic density around the terminals of mossy fibers was also increased in KO mice. Although there were no significant differences in locomotor ability between KO and WT animals in their home cages or in the open field, young adult KO mice had an increased grip strength and a tendency to exhibit better motor performance in balance-related tests compared with WT animals. Taken together, our results suggest that v-KIND is required for compact dendritic growth and proper excitatory synaptic connections in cerebellar granule cells, which are necessary for normal motor coordination and balance. PMID:28264072

  16. Is Cerebellar Architecture Shaped by Sensory Ecology in the New Zealand Kiwi (Apteryx mantelli).

    Science.gov (United States)

    Corfield, Jeremy R; Kolominsky, Jeffrey; Craciun, Iulia; Mulvany-Robbins, Bridget E; Wylie, Douglas R

    2016-01-01

    Among some mammals and birds, the cerebellar architecture appears to be adapted to the animal's ecological niche, particularly their sensory ecology and behavior. This relationship is, however, not well understood. To explore this, we examined the expression of zebrin II (ZII) in the cerebellum of the kiwi (Apteryx mantelli), a fully nocturnal bird with auditory, tactile, and olfactory specializations and a reduced visual system. We predicted that the cerebellar architecture, particularly those regions receiving visual inputs and those that receive trigeminal afferents from their beak, would be modified in accordance with their unique way of life. The general stripe-and-transverse region architecture characteristic of birds is present in kiwi, with some differences. Folium IXcd was characterized by large ZII-positive stripes and all Purkinje cells in the flocculus were ZII positive, features that resemble those of small mammals and suggest a visual ecology unlike that of other birds. The central region in kiwi appeared reduced or modified, with folium IV containing ZII+/- stripes, unlike that of most birds, but similar to that of Chilean tinamous. It is possible that a reduced visual system has contributed to a small central region, although increased trigeminal input and flightlessness have undoubtedly played a role in shaping its architecture. Overall, like in mammals, the cerebellar architecture in kiwi and other birds may be substantially modified to serve a particular ecological niche, although we still require a larger comparative data set to fully understand this relationship.

  17. Casein Kinase 1δ Is an APC/CCdh1 Substrate that Regulates Cerebellar Granule Cell Neurogenesis

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    Clara Penas

    2015-04-01

    Full Text Available Although casein kinase 1δ (CK1δ is at the center of multiple signaling pathways, its role in the expansion of CNS progenitor cells is unknown. Using mouse cerebellar granule cell progenitors (GCPs as a model for brain neurogenesis, we demonstrate that the loss of CK1δ or treatment of GCPs with a highly selective small molecule inhibits GCP expansion. In contrast, CK1δ overexpression increases GCP proliferation. Thus, CK1δ appears to regulate GCP neurogenesis. CK1δ is targeted for proteolysis via the anaphase-promoting complex/cyclosome (APC/CCdh1 ubiquitin ligase, and conditional deletion of the APC/CCdh1 activator Cdh1 in cerebellar GCPs results in higher levels of CK1δ. APC/CCdh1 also downregulates CK1δ during cell-cycle exit. Therefore, we conclude that APC/CCdh1 controls CK1δ levels to balance proliferation and cell-cycle exit in the developing CNS. Similar studies in medulloblastoma cells showed that CK1δ holds promise as a therapeutic target.

  18. Stimulation of the N-methyl-D-aspartate receptor has a trophic effect on differentiating cerebellar granule cells

    DEFF Research Database (Denmark)

    Balázs, R; Hack, N; Jørgensen, Ole Steen

    1988-01-01

    N-methyl-D-aspartate (NMDA) supplementation of cerebellar cultures enriched in granule neurones (about 90%) prevented the extensive cell loss which occurs when cultivation takes place, in serum containing media, in the presence of 'low' K+ (5-15 mM). Estimation of tetanus toxin receptors and N......-CAM contents indicated that NMDA rescued primarily nerve cells. The influence of NMDA in promoting cell survival was blocked by the receptor antagonist, 2-amino-5-phosphonovalerate. The effect depended both on the concentration of NMDA and on the degree of depolarization of cells, the affinity in the presence...... of 15 mM K+ being similar to that of NMDA receptor binding. The results attest a new role for excitatory amino acid transmitters by showing that they can exert a stage-dependent trophic action on developing nerve cells....

  19. Calcium as a trigger for cerebellar long-term synaptic depression.

    Science.gov (United States)

    Finch, Elizabeth A; Tanaka, Keiko; Augustine, George J

    2012-09-01

    Cerebellar long-term depression (LTD) is a form of long-term synaptic plasticity that is triggered by calcium(Ca2+) signals in the postsynaptic Purkinje cell. This Ca2+comes both from IP3-mediated release from intracellular Ca2+ stores, as well as from Ca2+ influx through voltage-gated Ca2+ channels. The Ca2+ signal that triggers LTD occurs locally within dendritic spines and is due to supralinear summation of signals coming from these two Ca2+ sources. The properties of this postsynaptic Ca2+signal can explain several features of LTD, such as its associativity, synapse specificity, and dependence on thetiming of synaptic activity, and can account for the slow kinetics of LTD expression. Thus, from a Ca2+ signaling perspective, LTD is one of the best understood forms of synaptic plasticity.

  20. GABA-agonists induce the formation of low-affinity GABA-receptors on cultured cerebellar granule cells via preexisting high affinity GABA receptors

    DEFF Research Database (Denmark)

    Belhage, B; Meier, E; Schousboe, A

    1986-01-01

    The kinetics of specific GABA-binding to membranes isolated from cerebellar granule cells, cultured for 12 days from dissociated cerebella of 7-day-old rats was studied using [3H]GABA as the ligand. The granule cells were cultured in the presence of the specific GABA receptor agonist 4, 5, 6, 7-t...

  1. Light and electron microscopic localization of GABAA-receptors on cultured cerebellar granule cells and astrocytes using immunohistochemical techniques

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Hösli, E; Belhage, B;

    1991-01-01

    . At the light microscope level specific staining of GABAA-receptors was localized in various types of neurones in explant cultures of rat cerebellum using the indirect peroxidase-antiperoxidase (PAP) technique, whereas no specific staining was found in astrocytes. At the electron microscope level labeling...... of GABAA-receptors was observed in the plasma membrane of both the cell bodies and processes in dissociated primary cultures of cerebellar granule cells using an indirect preembedding immunogold staining technique which in contrast to the classical PAP technique allows quantitative estimations...... to be performed. Quantification of the labeling intensity revealed a higher concentration of GABAA-receptors per microns plasma membrane in the cell bodies than in the processes. In discrete areas an extremely high density of the GABAA-receptors was observed. No specific labeling of GABAA-receptors was observed...

  2. Electrophysiological Monitoring of Injury ProgressionIn the Rat Cerebellar Cortex

    Directory of Open Access Journals (Sweden)

    Gokhan eOrdek

    2014-10-01

    Full Text Available The changes of excitability in affected neural networks can be used as a marker to study the temporal course of traumatic brain injury (TBI. The cerebellum is an ideal platform to study brain injury mechanisms at the network level using the electrophysiological methods. Within its crystalline morphology, the cerebellar cortex contains highly organized topographical subunits that are defined by two main inputs, the climbing and mossy fibers. Here we demonstrate the use of cerebellar evoked potentials (EPs mediated through these afferent systems for monitoring the injury progression in a rat model of fluid percussion injury (FPI. A mechanical tap on the dorsal hand was used as a stimulus, and EPs were recorded from the paramedian lobule (PML of the posterior cerebellum via multi-electrode arrays (MEA. Post-injury evoked response amplitudes (EPAs were analyzed on a daily basis for one week and compared with pre-injury values. We found a trend of consistently decreasing EPAs in all nine animals, losing as much as 72±4% of baseline amplitudes measured before the injury. Notably, our results highlighted two particular time windows; the first 24 hours of injury in the acute period and day-3 to day-7 in the delayed period where the largest drops (~50% and 24% were observed in the EPAs. In addition, cross-correlations of spontaneous signals between electrode pairs declined (from 0.47±0.1 to 0.35±0.04, p<0.001 along with the EPAs throughout the week of injury. In support of the electrophysiological findings, immunohistochemical analysis at day-7 post-injury showed detectable Purkinje cell loss at low FPI pressures and more with the largest pressures used. Our results suggest that sensory evoked potentials recorded from the cerebellar surface can be a useful technique to monitor the course of cerebellar injury and identify the phases of injury progression even at mild levels.

  3. Developmental α₂-adrenergic regulation of noradrenergic synaptic facilitation at cerebellar GABAergic synapses.

    Science.gov (United States)

    Hirono, M; Nagao, S; Obata, K

    2014-01-03

    In the central nervous system, the normal development of neuronal circuits requires adequate temporal activation of receptors for individual neurotransmitters. Previous studies have demonstrated that α₂-adrenoceptor (α₂-AR) activation eliminates spontaneous action potentials of interneurons in the cerebellar molecular layer (MLIs) and subsequently reduces the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in Purkinje cells (PCs) after the second postnatal week. The magnitude of the α₂-adrenergic reduction in sIPSC frequency is enhanced during the third postnatal week because of an increase in firing-derived sIPSCs. However, little is known about the effects of α₂-AR activation by noradrenaline (NA) on cerebellar GABAergic synaptic transmission that is accompanied by the activation of other AR subtypes, α₁- and β-ARs. Here, we developmentally examined the roles of α₂-AR activation in the noradrenergic facilitation of sIPSCs in cerebellar PCs. Until the second postnatal week, when substantial inhibitory effects of α₂-ARs are absent, NA potentiated sIPSCs and maintained the increased sIPSC frequency, suggesting that NA causes long-lasting facilitation of GABAergic synaptic transmission through α₁- and β-AR activation. After the second postnatal week, NA transiently increased the sIPSC frequency, whereas blocking α₂-ARs sustained the noradrenergic sIPSC facilitation and increase in the firing rate of MLIs, suggesting that α₂-AR activation suppresses the noradrenergic facilitation of GABAergic synaptic transmission. The simultaneous activation of α₁- and β-ARs by their specific agonists mimicked the persistent facilitation of sIPSC frequency, which required extracellular signal-regulated kinase 1/2 activation. These findings indicate that NA acts as a neurotrophic factor that strengthens GABAergic synaptic transmission in the developing cerebellar cortex and that α₂-ARs temporally restrain the noradrenergic

  4. Optogenetic modulation and multi-electrode analysis of cerebellar networks in vivo.

    Directory of Open Access Journals (Sweden)

    Wolfgang Kruse

    Full Text Available The firing patterns of cerebellar Purkinje cells (PCs, as the sole output of the cerebellar cortex, determine and tune motor behavior. PC firing is modulated by various inputs from different brain regions and by cell-types including granule cells (GCs, climbing fibers and inhibitory interneurons. To understand how signal integration in PCs occurs and how subtle changes in the modulation of PC firing lead to adjustment of motor behaviors, it is important to precisely record PC firing in vivo and to control modulatory pathways in a spatio-temporal manner. Combining optogenetic and multi-electrode approaches, we established a new method to integrate light-guides into a multi-electrode system. With this method we are able to variably position the light-guide in defined regions relative to the recording electrode with micrometer precision. We show that PC firing can be precisely monitored and modulated by light-activation of channelrhodopsin-2 (ChR2 expressed in PCs, GCs and interneurons. Thus, this method is ideally suited to investigate the spatio/temporal modulation of PCs in anesthetized and in behaving mice.

  5. Optogenetic Modulation and Multi-Electrode Analysis of Cerebellar Networks In Vivo

    Science.gov (United States)

    Kruse, Wolfgang; Krause, Martin; Aarse, Janna; Mark, Melanie D.; Manahan-Vaughan, Denise; Herlitze, Stefan

    2014-01-01

    The firing patterns of cerebellar Purkinje cells (PCs), as the sole output of the cerebellar cortex, determine and tune motor behavior. PC firing is modulated by various inputs from different brain regions and by cell-types including granule cells (GCs), climbing fibers and inhibitory interneurons. To understand how signal integration in PCs occurs and how subtle changes in the modulation of PC firing lead to adjustment of motor behaviors, it is important to precisely record PC firing in vivo and to control modulatory pathways in a spatio-temporal manner. Combining optogenetic and multi-electrode approaches, we established a new method to integrate light-guides into a multi-electrode system. With this method we are able to variably position the light-guide in defined regions relative to the recording electrode with micrometer precision. We show that PC firing can be precisely monitored and modulated by light-activation of channelrhodopsin-2 (ChR2) expressed in PCs, GCs and interneurons. Thus, this method is ideally suited to investigate the spatio/temporal modulation of PCs in anesthetized and in behaving mice. PMID:25144735

  6. The effect of gallium nitride on long-term culture induced aging of neuritic function in cerebellar granule cells.

    Science.gov (United States)

    Chen, Chi-Ruei; Young, Tai-Horng

    2008-04-01

    Gallium nitride (GaN) has been developed for a variety of microelectronic and optical applications due to its unique electric property and chemical stability. In the present study, n-type and p-type GaN were used as substrates to culture cerebellar granule neurons to examine the effect of GaN on cell response for a long-term culture period. It was found that GaN could rapidly induce cultured neurons to exhibit a high phosphorylated Akt level after 20h of incubation. It was assumed that the anti-apoptotic effect of Akt phosphorylation could be correlated with cell survival, neurite growth and neuronal function for up to 35 days of incubation. Morphological studies showed GaN induced larger neuronal aggregates and neurite fasciculation to exhibit a dense fiber network after 8 days of incubation. Western blot analysis and immunocytochemical characterization showed that GaN still exhibited the expression of neurite growth and function, such as high levels of GAP-43, synapsin I and synaptophysin even after 35 days of incubation. In addition, survival of cerebellar granule neurons on GaN was improved by the analysis of lactate dehydrogenase (LDH) release from damaged cells. These results indicated that neuronal connections were formed on GaN by a gradual process from Akt activation and cell aggregation to develop neurite growth, fasciculation and function. Therefore, GaN offers a good model system to identify a well-characterized pattern of neuronal behavior for a long-term culture period, consistent with the development of a neurochip requiring the integration of biological system and semiconductor material.

  7. Selective stimulation of excitatory amino acid receptor subtypes and the survival of cerebellar granule cells in culture: effect of kainic acid

    DEFF Research Database (Denmark)

    Balázs, R; Hack, N; Jørgensen, Ole Steen

    1990-01-01

    Our previous studies showed that the survival of cerebellar granule cells in culture is promoted by treatment with N-methyl-D-aspartate. Here we report on the influence of another glutamate analogue, kainic acid, which, in contrast to N-methyl-D-aspartate, is believed to stimulate transmitter rec...

  8. Cerebellar-dependent associative learning is preserved in Duchenne muscular dystrophy: a study using delay eyeblink conditioning.

    Directory of Open Access Journals (Sweden)

    Ulrike Schara

    Full Text Available Besides progressive muscle weakness cognitive deficits have been reported in patients with Duchenne muscular dystrophy (DMD. Cerebellar dysfunction has been proposed to explain cognitive deficits at least in part. In animal models of DMD disturbed Purkinje cell function has been shown following loss of dystrophin. Furthermore there is increasing evidence that the lateral cerebellum contributes to cognitive processing. In the present study cerebellar-dependent delay eyeblink conditioning, a form of associative learning, was used to assess cerebellar function in DMD children.Delay eyeblink conditioning was examined in eight genetically defined male patients with DMD and in ten age-matched control subjects. Acquisition, timing and extinction of conditioned eyeblink responses (CR were assessed during a single conditioning session.Both groups showed a significant increase of CRs during the course of learning (block effect p < 0.001. CR acquisition was not impaired in DMD patients (mean total CR incidence 37.4 ± 17.6% as compared to control subjects (36.2 ± 17.3%; group effect p = 0.89; group by block effect p = 0.38; ANOVA with repeated measures. In addition, CR timing and extinction was not different from controls.Delay eyeblink conditioning was preserved in the present DMD patients. Because eyeblink conditioning depends on the integrity of the intermediate cerebellum, this older part of the cerebellum may be relatively preserved in DMD. The present findings agree with animal model data showing that the newer, lateral cerebellum is primarily affected in DMD.

  9. The long-term structural plasticity of cerebellar parallel fiber axons and its modulation by motor learning.

    Science.gov (United States)

    Carrillo, Jennifer; Cheng, Shao-Ying; Ko, Kwang Woo; Jones, Theresa A; Nishiyama, Hiroshi

    2013-05-08

    Presynaptic axonal varicosities, like postsynaptic spines, are dynamically added and eliminated even in mature neuronal circuitry. To study the role of this axonal structural plasticity in behavioral learning, we performed two-photon in vivo imaging of cerebellar parallel fibers (PFs) in adult mice. PFs make excitatory synapses on Purkinje cells (PCs) in the cerebellar cortex, and long-term potentiation and depression at PF-PC synapses are thought to play crucial roles in cerebellar-dependent learning. Time-lapse vital imaging of PFs revealed that, under a control condition (no behavioral training), ∼10% of PF varicosities appeared and disappeared over a period of 2 weeks without changing the total number of varicosities. The fraction of dynamic PF varicosities significantly diminished during training on an acrobatic motor skill learning task, largely because of reduced addition of new varicosities. Thus, this form of motor learning was associated with greater structural stability of PFs and a slight decrease in the total number of varicosities. Together with prior findings that the number of PF-PC synapses increases during similar training, our results suggest that acrobatic motor skill learning involves a reduction of some PF inputs and a strengthening of others, probably via the conversion of some preexisting PF varicosities into multisynaptic terminals.

  10. The chemokine growth-related gene product β protects rat cerebellar granule cells from apoptotic cell death through α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors

    Science.gov (United States)

    Limatola, Cristina; Ciotti, Maria Teresa; Mercanti, Delio; Vacca, Fabrizio; Ragozzino, Davide; Giovannelli, Aldo; Santoni, Angela; Eusebi, Fabrizio; Miledi, Ricardo

    2000-01-01

    Cultured cerebellar granule neurons are widely used as a cellular model to study mechanisms of neuronal cell death because they undergo programmed cell death when switched from a culture medium containing 25 mM to one containing 5 mM K+. We have found that the growth-related gene product β (GROβ) partially prevents the K+-depletion-induced cell death, and that the neuroprotective action of GROβ on granule cells is mediated through the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type of ionotropic glutamate receptors. GROβ-induced survival was suppressed by 6-cyano-7-nitroquinoxaline-2,3-dione, which is a specific antagonist of AMPA/kainate receptors; it was not affected by the inhibitor of N-methyl-d-aspartate receptors, 2-amino-5-phosphonopentanoic acid, and was comparable to the survival of granule cells induced by AMPA (10 μM) treatment. Moreover, GROβ-induced neuroprotection was abolished when granule cells were treated with antisense oligonucleotides specific for the AMPA receptor subunits, which significantly reduced receptor expression, as verified by Western blot analysis with subunit-specific antibodies and by granule cell electrophysiological sensitivity to AMPA. Our data demonstrate that GROβ is neurotrophic for cerebellar granule cells, and that this activity depends on AMPA receptors. PMID:10811878

  11. Spike-coding mechanisms of cerebellar temporal processing in classical conditioning and voluntary movements.

    Science.gov (United States)

    Yamaguchi, Kenji; Sakurai, Yoshio

    2014-10-01

    Time is a fundamental and critical factor in daily life. Millisecond timing, which is the underlying temporal processing for speaking, dancing, and other activities, is reported to rely on the cerebellum. In this review, we discuss the cerebellar spike-coding mechanisms for temporal processing. Although the contribution of the cerebellum to both classical conditioning and voluntary movements is well known, the difference of the mechanisms for temporal processing between classical conditioning and voluntary movements is not clear. Therefore, we review the evidence of cerebellar temporal processing in studies of classical conditioning and voluntary movements and report the similarities and differences between them. From some studies, which used tasks that can change some of the temporal properties (e.g., the duration of interstimulus intervals) with keeping identical movements, we concluded that classical conditioning and voluntary movements may share a common spike-coding mechanism because simple spikes in Purkinje cells decrease at predicted times for responses regardless of the intervals between responses or stimulation.

  12. Circadian oscillations of molecular clock components in the cerebellar cortex of the rat.

    Science.gov (United States)

    Rath, Martin F; Rohde, Kristian; Møller, Morten

    2012-12-01

    The central circadian clock of the mammalian brain resides in the suprachiasmatic nucleus (SCN) of the hypothalamus. At the molecular level, the circadian clockwork of the SCN constitutes a self-sustained autoregulatory feedback mechanism reflected by the rhythmic expression of clock genes. However, recent studies have shown the presence of extrahypothalamic oscillators in other areas of the brain including the cerebellum. In the present study, the authors unravel the cerebellar molecular clock by analyzing clock gene expression in the cerebellum of the rat by use of radiochemical in situ hybridization and quantitative real-time polymerase chain reaction. The authors here show that all core clock genes, i.e., Per1, Per2, Per3, Cry1, Cry2, Clock, Arntl, and Nr1d1, as well as the clock-controlled gene Dbp, are expressed in the granular and Purkinje cell layers of the cerebellar cortex. Among these genes, Per1, Per2, Per3, Cry1, Arntl, Nr1d1, and Dbp were found to exhibit circadian rhythms in a sequential temporal manner similar to that of the SCN, but with several hours of delay. The results of lesion studies indicate that the molecular oscillatory profiles of Per1, Per2, and Cry1 in the cerebellum are controlled, though possibly indirectly, by the central clock of the SCN. These data support the presence of a circadian oscillator in the cortex of the rat cerebellum.

  13. Gamma-aminobutyric acid agonist-induced alterations in the ultrastructure of cultured cerebellar granule cells is restricted to early development

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Belhage, B; Schousboe, A;

    1988-01-01

    The effect of 4,5,6,7-tetrahydroisoxazolo[5,4-c]-pyridin-3-ol (THIP) on the ultrastructural composition of cultured cerebellar granule cells was investigated during development by quantitative electron microscopy (morphometric analysis). Granule cells were exposed to THIP (150 microM) for 6 h after...... 7 and 14 days, respectively, in culture. THIP treatment of 7-day-old cultures led to a statistically significant increase in the cytoplasmic density of rough endoplasmic reticulum, Golgi apparatus, vesicles, and coated vesicles, whereas no significant increase in the cytoplasmic density...... of these organelles was observed in 14-day-old cultures exposed to THIP for 6 h. These findings show that the effect of THIP on the ultrastructural composition of cultured cerebellar granule cells is restricted to early development....

  14. 小脑肽1对浦肯野细胞突触形成作用的最新研究进展%The Advance on Studies of Cerebellin 1 Effects on Synapses Formation of Purkinje Cells

    Institute of Scientific and Technical Information of China (English)

    遇春霖; 张忠玲

    2015-01-01

    Cerebellin 1 is a glycoprotein in the cerebellum, which is produced and secreted from granule cells and works as a strong synapse organizer between Purkinje cells and parallel ifbers, the axons of the granule cells. The molecular mechanisms by which Cbln1 induces synapse formation were described and the related literature was reviewed.%小脑肽1是一种小脑中的特异性糖蛋白,由颗粒细胞生成并分泌,在颗粒细胞的平行纤维和浦肯野细胞之间的兴奋性突触形成过程中发挥重要作用。文中将详细描述小脑肽1诱导新生突触形成的分子机制。复习相关方面的文献,就小脑肽1对于浦肯野细胞上突触的形成以及兴奋与抑制传入的调节作用的研究现状作详细介绍。

  15. Cell-type-specific neuroanatomy of cliques of autism-related genes in the mouse brain

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    Pascal eGrange

    2015-05-01

    Full Text Available Two cliques of genes identified computationally for their high co-expression in the mouse brain according to the Allen Brain Atlas, and for their enrichment in genes related to autism spectrum disorder, have recently been shown to be highly co-expressed in the cerebellar cortex, compared to what could be expected by chance. Moreover, the expression of these cliques of genes is not homogeneous across the cerebellar cortex, and it has been noted that their expression pattern seems to highlight the granular layer. However, this observation was only made by eye, and recent advances in computational neuroanatomy allow to rank cell types in the mouse brain (characterized by their transcriptome profiles according to the similarity between their spatial density profiles and the expression profiles of the cliques. We establish by Monte Carlo simulation that with probability at least 99%, the expression profiles of the two cliques are more similar to the density profile of granule cells than 99% of the expression of cliques containing the same number of genes (Purkinje cells also score above 99% in one of the cliques. Thresholding the expression profiles shows that the signal is more intense in the granular layer. Finally, we work out pairs of cell types whose combined expression profiles are more similar to the expression profiles of the cliquesthan any single cell type. These pairs predominantly consist of one cortical pyramidal cell and one cerebellar cell (whichcan be either a granule cell or a Purkinje cell.

  16. mGluR1-mediated excitation of cerebellar GABAergic interneurons requires both G protein-dependent and Src-ERK1/2-dependent signaling pathways.

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    Hideo Kubota

    Full Text Available Stimulation of type I metabotropic glutamate receptors (mGluR1/5 in several neuronal types induces slow excitatory responses through activation of transient receptor potential canonical (TRPC channels. GABAergic cerebellar molecular layer interneurons (MLIs modulate firing patterns of Purkinje cells (PCs, which play a key role in cerebellar information processing. MLIs express mGluR1, and activation of mGluR1 induces an inward current, but its precise intracellular signaling pathways are unknown. We found that mGluR1 activation facilitated spontaneous firing of mouse cerebellar MLIs through an inward current mediated by TRPC1 channels. This mGluR1-mediated inward current depends on both G protein-dependent and -independent pathways. The nonselective protein tyrosine kinase inhibitors genistein and AG490 as well as the selective extracellular signal-regulated kinase 1/2 (ERK1/2 inhibitors PD98059 and SL327 suppressed the mGluR1-mediated current responses. Following G protein blockade, the residual mGluR1-mediated inward current was significantly reduced by the selective Src tyrosine kinase inhibitor PP2. In contrast to cerebellar PCs, GABAB receptor activation in MLIs did not alter the mGluR1-mediated inward current, suggesting that there is no cross-talk between mGluR1 and GABAB receptors in MLIs. Thus, activation of mGluR1 facilitates firing of MLIs through the TRPC1-mediated inward current, which depends on not only G protein-dependent but also Src-ERK1/2-dependent signaling pathways, and consequently depresses the excitability of cerebellar PCs.

  17. Caffeine Modulates Vesicle Release and Recovery at Cerebellar Parallel Fibre Terminals, Independently of Calcium and Cyclic AMP Signalling.

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    Katharine L Dobson

    Full Text Available Cerebellar parallel fibres release glutamate at both the synaptic active zone and at extrasynaptic sites-a process known as ectopic release. These sites exhibit different short-term and long-term plasticity, the basis of which is incompletely understood but depends on the efficiency of vesicle release and recycling. To investigate whether release of calcium from internal stores contributes to these differences in plasticity, we tested the effects of the ryanodine receptor agonist caffeine on both synaptic and ectopic transmission.Whole cell patch clamp recordings from Purkinje neurons and Bergmann glia were carried out in transverse cerebellar slices from juvenile (P16-20 Wistar rats.Caffeine caused complex changes in transmission at both synaptic and ectopic sites. The amplitude of postsynaptic currents in Purkinje neurons and extrasynaptic currents in Bergmann glia were increased 2-fold and 4-fold respectively, but paired pulse ratio was substantially reduced, reversing the short-term facilitation observed under control conditions. Caffeine treatment also caused synaptic sites to depress during 1 Hz stimulation, consistent with inhibition of the usual mechanisms for replenishing vesicles at the active zone. Unexpectedly, pharmacological intervention at known targets for caffeine--intracellular calcium release, and cAMP signalling--had no impact on these effects.We conclude that caffeine increases release probability and inhibits vesicle recovery at parallel fibre synapses, independently of known pharmacological targets. This complex effect would lead to potentiation of transmission at fibres firing at low frequencies, but depression of transmission at high frequency connections.

  18. Rabbit cerebellar slice analysis of long-term depression and its role in classical conditioning.

    Science.gov (United States)

    Schreurs, B G; Alkon, D L

    1993-12-24

    Cerebellar long-term depression (LTD) has been proposed as a mechanism underlying classical conditioning of the rabbit nictitating membrane/eyelid response (NMR). However, LTD has only been obtained reliably when (1) cerebellar slices are bathed in GABA antagonists which abolish disynaptic inhibitory post synaptic potentials, and (2) the temporal sequence of stimulation used in slice or intact preparations is the opposite of that used in classical conditioning. Based on intradendritic Purkinje cell recordings obtained from rabbit cerebellar slices, we report that stimulation of climbing fibers and then parallel fibers in the presence of the GABA antagonist, bicuculline, produced significant depression of parallel fiber excitatory post synaptic potential (epsp) amplitude that continued to increase for at least 20 min after stimulation. However, application of the same stimulation protocol without GABA antagonists produced a brief depression of parallel fiber epsps that disappeared within minutes. Activation of parallel fibers and then climbing fibers in an order opposite to the LTD-producing sequence (i.e. a classical conditioning-like order) produced a brief depression that dissipated quickly. Stimulation of parallel fibers alone produced a small, slowly developing potentiation, but stimulation of parallel fibers during depolarization-induced local dendritic calcium spikes produced significant depression almost immediately which then declined slowly to more modest levels. Finally, stimulation of parallel fibers at frequencies used in in vivo parallel fiber-climbing fiber stimulation experiments (e.g. 100 Hz) produced an immediate and profound long-lasting epsp depression. The depression occurred, however, whether parallel and climbing fibers were stimulated separately (unpaired) or in a classical conditioning-like protocol (paired) where parallel fiber stimulation coterminated with climbing fiber stimulation (10 Hz).(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Conditional induction of Math1 specifies embryonic stem cells to cerebellar granule neuron lineage and promotes differentiation into mature granule neurons.

    Science.gov (United States)

    Srivastava, Rupali; Kumar, Manoj; Peineau, Stéphane; Csaba, Zsolt; Mani, Shyamala; Gressens, Pierre; El Ghouzzi, Vincent

    2013-04-01

    Directing differentiation of embryonic stem cells (ESCs) to specific neuronal subtype is critical for modeling disease pathology in vitro. An attractive means of action would be to combine regulatory differentiation factors and extrinsic inductive signals added to the culture medium. In this study, we have generated mature cerebellar granule neurons by combining a temporally controlled transient expression of Math1, a master gene in granule neuron differentiation, with inductive extrinsic factors involved in cerebellar development. Using a Tetracyclin-On transactivation system, we overexpressed Math1 at various stages of ESCs differentiation and found that the yield of progenitors was considerably increased when Math1 was induced during embryonic body stage. Math1 triggered expression of Mbh1 and Mbh2, two target genes directly involved in granule neuron precursor formation and strong expression of early cerebellar territory markers En1 and NeuroD1. Three weeks after induction, we observed a decrease in the number of glial cells and an increase in that of neurons albeit still immature. Combining Math1 induction with extrinsic factors specifically increased the number of neurons that expressed Pde1c, Zic1, and GABAα6R characteristic of mature granule neurons, formed "T-shaped" axons typical of granule neurons, and generated synaptic contacts and action potentials in vitro. Finally, in vivo implantation of Math1-induced progenitors into young adult mice resulted in cell migration and settling of newly generated neurons in the cerebellum. These results show that conditional induction of Math1 drives ESCs toward the cerebellar fate and indicate that acting on both intrinsic and extrinsic factors is a powerful means to modulate ESCs differentiation and maturation into a specific neuronal lineage.

  20. Distinct early molecular responses to mutations causing vLINCL and JNCL presage ATP synthase subunit C accumulation in cerebellar cells.

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    Yi Cao

    Full Text Available Variant late-infantile neuronal ceroid lipofuscinosis (vLINCL, caused by CLN6 mutation, and juvenile neuronal ceroid lipofuscinosis (JNCL, caused by CLN3 mutation, share clinical and pathological features, including lysosomal accumulation of mitochondrial ATP synthase subunit c, but the unrelated CLN6 and CLN3 genes may initiate disease via similar or distinct cellular processes. To gain insight into the NCL pathways, we established murine wild-type and CbCln6(nclf/nclf cerebellar cells and compared them to wild-type and CbCln3(Δex7/8/Δex7/8 cerebellar cells. CbCln6(nclf/nclf cells and CbCln3(Δex7/8/Δex7/8 cells both displayed abnormally elongated mitochondria and reduced cellular ATP levels and, as cells aged to confluence, exhibited accumulation of subunit c protein in Lamp 1-positive organelles. However, at sub-confluence, endoplasmic reticulum PDI immunostain was decreased only in CbCln6(nclf/nclf cells, while fluid-phase endocytosis and LysoTracker® labeled vesicles were decreased in both CbCln6(nclf/nclf and CbCln3(Δex7/8/Δex7/8 cells, though only the latter cells exhibited abnormal vesicle subcellular distribution. Furthermore, unbiased gene expression analyses revealed only partial overlap in the cerebellar cell genes and pathways that were altered by the Cln3(Δex7/8 and Cln6(nclf mutations. Thus, these data support the hypothesis that CLN6 and CLN3 mutations trigger distinct processes that converge on a shared pathway, which is responsible for proper subunit c protein turnover and neuronal cell survival.

  1. Alteration of AMPA Receptor-Mediated Synaptic Transmission by Alexa Fluor 488 and 594 in Cerebellar Stellate Cells.

    Science.gov (United States)

    Maroteaux, Matthieu; Liu, Siqiong June

    2016-01-01

    The fluorescent dyes, Alexa Fluor 488 and 594 are commonly used to visualize dendritic structures and the localization of synapses, both of which are critical for the spatial and temporal integration of synaptic inputs. However, the effect of the dyes on synaptic transmission is not known. Here we investigated whether Alexa Fluor dyes alter the properties of synaptic currents mediated by two subtypes of AMPA receptors (AMPARs) at cerebellar stellate cell synapses. In naive mice, GluA2-lacking AMPAR-mediated synaptic currents displayed an inwardly rectifying current-voltage (I-V) relationship due to blockade by cytoplasmic spermine at depolarized potentials. We found that the inclusion of 100 µm Alexa Fluor dye, but not 10 µm, in the pipette solution led to a gradual increase in the amplitude of EPSCs at +40 mV and a change in the I-V relationship from inwardly rectifying to more linear. In mice exposed to an acute stress, AMPARs switched to GluA2-containing receptors, and 100 µm Alexa Fluor 594 did not alter the I-V relationship of synaptic currents. Therefore, a high concentration of Alexa Fluor dye changed the I-V relationship of EPSCs at GluA2-lacking AMPAR synapses.

  2. Robert Feulgen Prize Lecture. Grenzgänger: adult bone marrow cells populate the brain.

    Science.gov (United States)

    Priller, Josef

    2003-08-01

    While the brain has traditionally been considered a rather secluded site, recent studies suggest that adult bone marrow (BM)-derived stem cells can generate glia and neurons in rodents and humans. Macrophages and microglia are the first to appear in the murine brain after transplantation of genetically marked BM cells. Within weeks after transplantation, some authors have found astrocytes and cells expressing neuronal antigens. We detected cerebellar Purkinje neurons and interneurons, such as basket cells, expressing the green fluorescent protein (GFP) 10-15 months after transplantation of GFP-labeled BM cells. The results push the boundaries of our classic view of lineage restriction.

  3. Tunable Oscillations in the Purkinje Neuron

    CERN Document Server

    Abrams, Ze'ev R; Wang, Yuan; Trauner, Dirk; Zhang, Xiang

    2011-01-01

    In this paper, we study the dynamics of slow oscillations in Purkinje neurons in vitro, and derive a strong association with a forced parametric oscillator model. We demonstrate the precise rhythmicity of the oscillations in Purkinje neurons, as well as a dynamic tunability of this oscillation using a photo-switchable compound. We show that this slow oscillation can be induced in every Purkinje neuron, having periods ranging between 10-25 seconds. Starting from a Hodgkin-Huxley model, we also demonstrate that this oscillation can be externally modulated, and that the neurons will return to their intrinsic firing frequency after the forced oscillation is concluded. These results signify an additional functional role of tunable oscillations within the cerebellum, as well as a dynamic control of a time scale in the brain in the range of seconds.

  4. Apoptotic cell death of cerebellar granule neurons in genetically ataxia (ax) mice.

    Science.gov (United States)

    Ohgoh, M; Yamazaki, K; Ogura, H; Nishizawa, Y; Tanaka, I

    2000-07-21

    An autosomal recessive neurological mutant, ataxia (ax) mouse, was investigated to determine whether neuronal cell death occurs in the brain. The brains of homozygotes (ax(J)/ax(J)) and phenotypically normal littermates (ax(J)/+ or +/+) aged at 23-38 days were examined by the terminal dUTP nick-end-labeling (TUNEL) method. A few TUNEL-positive cells were observed in the granule cell layer of the cerebellum, the dentate gyrus, and the olfactory bulb of normal mice. In the affected mice, the number of TUNEL-positive cells was significantly increased in the cerebellum, particularly in the granule cell layer, compared to normal littermates. The findings suggest that ax mice will be useful as a model for studies on the genetic basis of apoptotic neuronal cell death.

  5. Development and specification of cerebellar stem and progenitor cells in zebrafish: from embryo to adult

    OpenAIRE

    Kaslin, Jan; Kroehne, Volker; Benato, Francesca; Argenton, Francesco; Brand, Michael

    2013-01-01

    Background Teleost fish display widespread post-embryonic neurogenesis originating from many different proliferative niches that are distributed along the brain axis. During the development of the central nervous system (CNS) different cell types are produced in a strict temporal order from increasingly committed progenitors. However, it is not known whether diverse neural stem and progenitor cell types with restricted potential or stem cells with broad potential are maintained in the teleost...

  6. Inhibition of Ca2+-activated large-conductance K+ channel activity alters synaptic AMPA receptor phenotype in mouse cerebellar stellate cells

    OpenAIRE

    Yu LIU; Savtchouk, Iaroslav; Acharjee, Shoana; Liu, Siqiong June

    2011-01-01

    Many fast-spiking inhibitory interneurons, including cerebellar stellate cells, fire brief action potentials and express α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptors (AMPAR) that are permeable to Ca2+ and do not contain the GluR2 subunit. In a recent study, we found that increasing action potential duration promotes GluR2 gene transcription in stellate cells. We have now tested the prediction that activation of potassium channels that control the durati...

  7. Fast-reset of pacemaking and theta-frequency resonance patterns in cerebellar golgi cells: Simulations of their impact in vivo

    Directory of Open Access Journals (Sweden)

    Sergio Solinas

    2007-12-01

    Full Text Available The Golgi cells are inhibitory interneurons of the cerebellar granular layer, which respond to afferent stimulation in vivo with a burst-pause sequence interrupting their irregular background low-frequency firing (Vos et al., 1999a. Eur. J. Neurosci. 11, 2621–2634. However, Golgi cells in vitro are regular pacemakers (Forti et al., 2006. J. Physiol. 574, 711–729, raising the question how their ionic mechanisms could impact on responses during physiological activity. Using patch-clamp recordings in cerebellar slices we show that the pacemaker cycle can be suddenly reset by spikes, making the cell highly sensitive to input variations. Moreover, the neuron resonates around the pacemaker frequency, making it specifically sensitive to patterned stimulation in the theta-frequency band. Computational analysis based on a model developed to reproduce Golgi cell pacemaking (Solinas et al., 2008 Front. Neurosci., 1:2 predicted that phase-reset required spike-triggered activation of SK channels and that resonance was sustained by a slow voltage-dependent potassium current and amplified by a persistent sodium current. Adding balanced synaptic noise to mimic the irregular discharge observed in vivo, we found that pacemaking converts into spontaneous irregular discharge, that phase-reset plays an important role in generating the burst-pause pattern evoked by sensory stimulation, and that repetitive stimulation at theta-frequency enhances the time-precision of spike coding in the burst. These results suggest that Golgi cell intrinsic properties exert a profound impact on time-dependent signal processing in the cerebellar granular layer.

  8. Fast-reset of pacemaking and theta-frequency resonance patterns in cerebellar golgi cells: simulations of their impact in vivo.

    Science.gov (United States)

    Solinas, Sergio; Forti, Lia; Cesana, Elisabetta; Mapelli, Jonathan; De Schutter, Erik; D'Angelo, Egidio

    2007-01-01

    The Golgi cells are inhibitory interneurons of the cerebellar granular layer, which respond to afferent stimulation in vivo with a burst-pause sequence interrupting their irregular background low-frequency firing (Vos et al., 1999a. Eur. J. Neurosci. 11, 2621-2634). However, Golgi cells in vitro are regular pacemakers (Forti et al., 2006. J. Physiol. 574, 711-729), raising the question how their ionic mechanisms could impact on responses during physiological activity. Using patch-clamp recordings in cerebellar slices we show that the pacemaker cycle can be suddenly reset by spikes, making the cell highly sensitive to input variations. Moreover, the neuron resonates around the pacemaker frequency, making it specifically sensitive to patterned stimulation in the theta-frequency band. Computational analysis based on a model developed to reproduce Golgi cell pacemaking (Solinas et al., 2008Front. Neurosci., 2:2) predicted that phase-reset required spike-triggered activation of SK channels and that resonance was sustained by a slow voltage-dependent potassium current and amplified by a persistent sodium current. Adding balanced synaptic noise to mimic the irregular discharge observed in vivo, we found that pacemaking converts into spontaneous irregular discharge, that phase-reset plays an important role in generating the burst-pause pattern evoked by sensory stimulation, and that repetitive stimulation at theta-frequency enhances the time-precision of spike coding in the burst. These results suggest that Golgi cell intrinsic properties exert a profound impact on time-dependent signal processing in the cerebellar granular layer.

  9. Image-Based Structural Modeling of the Cardiac Purkinje Network

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    Benjamin R. Liu

    2015-01-01

    Full Text Available The Purkinje network is a specialized conduction system within the heart that ensures the proper activation of the ventricles to produce effective contraction. Its role during ventricular arrhythmias is less clear, but some experimental studies have suggested that the Purkinje network may significantly affect the genesis and maintenance of ventricular arrhythmias. Despite its importance, few structural models of the Purkinje network have been developed, primarily because current physical limitations prevent examination of the intact Purkinje network. In previous modeling efforts Purkinje-like structures have been developed through either automated or hand-drawn procedures, but these networks have been created according to general principles rather than based on real networks. To allow for greater realism in Purkinje structural models, we present a method for creating three-dimensional Purkinje networks based directly on imaging data. Our approach uses Purkinje network structures extracted from photographs of dissected ventricles and projects these flat networks onto realistic endocardial surfaces. Using this method, we create models for the combined ventricle-Purkinje system that can fully activate the ventricles through a stimulus delivered to the Purkinje network and can produce simulated activation sequences that match experimental observations. The combined models have the potential to help elucidate Purkinje network contributions during ventricular arrhythmias.

  10. Acute onset paraneoplastic cerebellar degeneration in a patient with small cell lung cancer

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    Bhatia R

    2003-04-01

    Full Text Available A patient with small cell lung cancer presented with a rare presentation of an acute onset pancerebellar dysfunction. His clinical condition markedly improved following the surgical removal of the tumor and chemo- and radiotherapy.

  11. Inhibition of Ca2+-activated large-conductance K+ channel activity alters synaptic AMPA receptor phenotype in mouse cerebellar stellate cells.

    Science.gov (United States)

    Liu, Yu; Savtchouk, Iaroslav; Acharjee, Shoana; Liu, Siqiong June

    2011-07-01

    Many fast-spiking inhibitory interneurons, including cerebellar stellate cells, fire brief action potentials and express α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptors (AMPAR) that are permeable to Ca(2+) and do not contain the GluR2 subunit. In a recent study, we found that increasing action potential duration promotes GluR2 gene transcription in stellate cells. We have now tested the prediction that activation of potassium channels that control the duration of action potentials can suppress the expression of GluR2-containing AMPARs at stellate cell synapses. We find that large-conductance Ca(2+)-activated potassium (BK) channels mediate a large proportion of the depolarization-evoked noninactivating potassium current in stellate cells. Pharmacological blockade of BK channels prolonged the action potential duration in postsynaptic stellate cells and altered synaptic AMPAR subtype from GluR2-lacking to GluR2-containing Ca(2+)-impermeable AMPARs. An L-type channel blocker abolished an increase in Ca(2+) entry that was associated with spike broadening and also prevented the BK channel blocker-induced switch in AMPAR phenotype. Thus blocking BK potassium channels prolongs the action potential duration and increases the expression of GluR2-containing receptors at the synapse by enhancing Ca(2+) entry in cerebellar stellate cells.

  12. Stereological estimation of total cell numbers in the human cerebral and cerebellar cortex

    DEFF Research Database (Denmark)

    Walløe, Solveig; Pakkenberg, Bente; Fabricius, Katrine

    2014-01-01

    Our knowledge of the relationship between brain structure and cognitive function is still limited. Human brains and individual cortical areas vary considerably in size and shape. Studies of brain cell numbers have historically been based on biased methods, which did not always result in correct e...

  13. Bilateral otogenic cerebellar abscesses.

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    Nadkarni T

    1993-01-01

    Full Text Available An unusual presentation of bilateral otogenic cerebellar abscesses observed in two of our patients is reported. Both gave a history of otorrhoea, fever, headache, vomiting and had bilateral cerebellar signs and conductive hearing loss. The abscesses were detected on computerised tomography. X-rays revealed bilateral mastoiditis. The therapy followed was excision of abscesses, mastoidectomy and antibiotic therapy.

  14. FGF/FGFR2 signaling regulates the generation and correct positioning of Bergmann glia cells in the developing mouse cerebellum.

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    Florian Meier

    Full Text Available The normal cellular organization and layering of the vertebrate cerebellum is established during embryonic and early postnatal development by the interplay of a complex array of genetic and signaling pathways. Disruption of these processes and of the proper layering of the cerebellum usually leads to ataxic behaviors. Here, we analyzed the relative contribution of Fibroblast growth factor receptor 2 (FGFR2-mediated signaling to cerebellar development in conditional Fgfr2 single mutant mice. We show that during embryonic mouse development, Fgfr2 expression is higher in the anterior cerebellar primordium and excluded from the proliferative ventricular neuroepithelium. Consistent with this finding, conditional Fgfr2 single mutant mice display the most prominent defects in the anterior lobules of the adult cerebellum. In this context, FGFR2-mediated signaling is required for the proper generation of Bergmann glia cells and the correct positioning of these cells within the Purkinje cell layer, and for cell survival in the developing cerebellar primordium. Using cerebellar microexplant cultures treated with an FGFR agonist (FGF9 or antagonist (SU5402, we also show that FGF9/FGFR-mediated signaling inhibits the outward migration of radial glia and Bergmann glia precursors and cells, and might thus act as a positioning cue for these cells. Altogether, our findings reveal the specific functions of the FGFR2-mediated signaling pathway in the generation and positioning of Bergmann glia cells during cerebellar development in the mouse.

  15. Characterization of two novel nuclear BTB/POZ domain zinc finger isoforms. Association with differentiation of hippocampal neurons, cerebellar granule cells, and macroglia

    DEFF Research Database (Denmark)

    Mitchelmore, Cathy; Kjaerulff, Karen M; Pedersen, Hans C

    2002-01-01

    BTB/POZ (broad complex tramtrack bric-a-brac/poxvirus and zinc finger) zinc finger factors are a class of nuclear DNA-binding proteins involved in development, chromatin remodeling, and cancer. However, BTB/POZ domain zinc finger factors linked to development of the mammalian cerebral cortex......, cerebellum, and macroglia have not been described previously. We report here the isolation and characterization of two novel nuclear BTB/POZ domain zinc finger isoforms, designated HOF(L) and HOF(S), that are specifically expressed in early hippocampal neurons, cerebellar granule cells, and gliogenic...

  16. Glutamate receptor activation in cultured cerebellar granule cells increases cytosolic free Ca2+ by mobilization of cellular Ca2+ and activation of Ca2+ influx

    DEFF Research Database (Denmark)

    Bouchelouche, P; Belhage, B; Frandsen, A;

    1989-01-01

    The Ca2+ sensitive fluorescent probe, fura-2 has been used to monitor cytosolic free calcium levels in mature primary cultures of cerebellar granule cells during exposure to L-glutamate and other excitatory amino acids: quisqualate (QA) kainate (KA) and N-methyl-D-aspartate (NMDA). Glutamate...... at micromolar concentrations produced a prompt and dose-related increase in the intracellular concentration of free Ca2+, ([Ca2+]i), whereas QA, KA and NMDA had no effect. This increase was also seen in the absence of extracellular Ca2+, suggesting that L-glutamate promotes mobilization of Ca2+ from...

  17. Importance of genetics in fetal alcohol effects: null mutation of the nNOS gene worsens alcohol-induced cerebellar neuronal losses and behavioral deficits.

    Science.gov (United States)

    Bonthius, Daniel J; Winters, Zachary; Karacay, Bahri; Bousquet, Samantha Larimer; Bonthius, Daniel J

    2015-01-01

    The cerebellum is a major target of alcohol-induced damage in the developing brain. However, the cerebella of some children are much more seriously affected than others by prenatal alcohol exposure. As a consequence of in utero alcohol exposure, some children have substantial reductions in cerebellar volume and corresponding neurodevelopmental problems, including microencephaly, ataxia, and balance deficits, while other children who were exposed to similar alcohol quantities are spared. One factor that likely plays a key role in determining the impact of alcohol on the fetal cerebellum is genetics. However, no specific gene variant has yet been identified that worsens cerebellar function as a consequence of developmental alcohol exposure. Previous studies have revealed that mice carrying a homozygous mutation of the gene for neuronal nitric oxide synthase (nNOS-/- mice) have more severe acute alcohol-induced neuronal losses from the cerebellum than wild type mice. Therefore, the goals of this study were to determine whether alcohol induces more severe cerebellum-based behavioral deficits in nNOS-/- mice than in wild type mice and to determine whether these worsened behavior deficits are associated with worsened cerebellar neuronal losses. nNOS-/- mice and their wild type controls received alcohol (0.0, 2.2, or 4.4mg/g) daily over postnatal days 4-9. In adulthood, the mice underwent behavioral testing, followed by neuronal quantification. Alcohol caused dose-related deficits in rotarod and balance beam performance in both nNOS-/- and wild type mice. However, the alcohol-induced behavioral deficits were substantially worse in the nNOS-/- mice than in wild type. Likewise, alcohol exposure led to losses of Purkinje cells and cerebellar granule cells in mice of both genotypes, but the cell losses were more severe in the nNOS-/- mice than in wild type. Behavioral performances were correlated with neuronal number in the nNOS-/- mice, but not in wild type. Thus, homozygous

  18. A new mouse allele of glutamate receptor delta 2 with cerebellar atrophy and progressive ataxia.

    Science.gov (United States)

    Miyoshi, Yuka; Yoshioka, Yoshichika; Suzuki, Kinuko; Miyazaki, Taisuke; Koura, Minako; Saigoh, Kazumasa; Kajimura, Naoko; Monobe, Yoko; Kusunoki, Susumu; Matsuda, Junichiro; Watanabe, Masahiko; Hayasaka, Naoto

    2014-01-01

    Spinocerebellar degenerations (SCDs) are a large class of sporadic or hereditary neurodegenerative disorders characterized by progressive motion defects and degenerative changes in the cerebellum and other parts of the CNS. Here we report the identification and establishment from a C57BL/6J mouse colony of a novel mouse line developing spontaneous progressive ataxia, which we refer to as ts3. Frequency of the phenotypic expression was consistent with an autosomal recessive Mendelian trait of inheritance, suggesting that a single gene mutation is responsible for the ataxic phenotype of this line. The onset of ataxia was observed at about three weeks of age, which slowly progressed until the hind limbs became entirely paralyzed in many cases. Micro-MRI study revealed significant cerebellar atrophy in all the ataxic mice, although individual variations were observed. Detailed histological analyses demonstrated significant atrophy of the anterior folia with reduced granule cells (GC) and abnormal morphology of cerebellar Purkinje cells (PC). Study by ultra-high voltage electron microscopy (UHVEM) further indicated aberrant morphology of PC dendrites and their spines, suggesting both morphological and functional abnormalities of the PC in the mutants. Immunohistochemical studies also revealed defects in parallel fiber (PF)-PC synapse formation and abnormal distal extension of climbing fibers (CF). Based on the phenotypic similarities of the ts3 mutant with other known ataxic mutants, we performed immunohistological analyses and found that expression levels of two genes and their products, glutamate receptor delta2 (grid2) and its ligand, cerebellin1 (Cbln1), are significantly reduced or undetectable. Finally, we sequenced the candidate genes and detected a large deletion in the coding region of the grid2 gene. Our present study suggests that ts3 is a new allele of the grid2 gene, which causes similar but different phenotypes as compared to other grid2 mutants.

  19. A new mouse allele of glutamate receptor delta 2 with cerebellar atrophy and progressive ataxia.

    Directory of Open Access Journals (Sweden)

    Yuka Miyoshi

    Full Text Available Spinocerebellar degenerations (SCDs are a large class of sporadic or hereditary neurodegenerative disorders characterized by progressive motion defects and degenerative changes in the cerebellum and other parts of the CNS. Here we report the identification and establishment from a C57BL/6J mouse colony of a novel mouse line developing spontaneous progressive ataxia, which we refer to as ts3. Frequency of the phenotypic expression was consistent with an autosomal recessive Mendelian trait of inheritance, suggesting that a single gene mutation is responsible for the ataxic phenotype of this line. The onset of ataxia was observed at about three weeks of age, which slowly progressed until the hind limbs became entirely paralyzed in many cases. Micro-MRI study revealed significant cerebellar atrophy in all the ataxic mice, although individual variations were observed. Detailed histological analyses demonstrated significant atrophy of the anterior folia with reduced granule cells (GC and abnormal morphology of cerebellar Purkinje cells (PC. Study by ultra-high voltage electron microscopy (UHVEM further indicated aberrant morphology of PC dendrites and their spines, suggesting both morphological and functional abnormalities of the PC in the mutants. Immunohistochemical studies also revealed defects in parallel fiber (PF-PC synapse formation and abnormal distal extension of climbing fibers (CF. Based on the phenotypic similarities of the ts3 mutant with other known ataxic mutants, we performed immunohistological analyses and found that expression levels of two genes and their products, glutamate receptor delta2 (grid2 and its ligand, cerebellin1 (Cbln1, are significantly reduced or undetectable. Finally, we sequenced the candidate genes and detected a large deletion in the coding region of the grid2 gene. Our present study suggests that ts3 is a new allele of the grid2 gene, which causes similar but different phenotypes as compared to other grid2

  20. Circadian oscillators in the mouse brain: molecular clock components in the neocortex and cerebellar cortex.

    Science.gov (United States)

    Rath, Martin F; Rovsing, Louise; Møller, Morten

    2014-09-01

    The circadian timekeeper of the mammalian brain resides in the suprachiasmatic nucleus of the hypothalamus (SCN), and is characterized by rhythmic expression of a set of clock genes with specific 24-h daily profiles. An increasing amount of data suggests that additional circadian oscillators residing outside the SCN have the capacity to generate peripheral circadian rhythms. We have recently shown the presence of SCN-controlled oscillators in the neocortex and cerebellum of the rat. The function of these peripheral brain clocks is unknown, and elucidating this could involve mice with conditional cell-specific clock gene deletions. This prompted us to analyze the molecular clockwork of the mouse neocortex and cerebellum in detail. Here, by use of in situ hybridization and quantitative RT-PCR, we show that clock genes are expressed in all six layers of the neocortex and the Purkinje and granular cell layers of the cerebellar cortex of the mouse brain. Among these, Per1, Per2, Cry1, Arntl, and Nr1d1 exhibit circadian rhythms suggesting that local running circadian oscillators reside within neurons of the mouse neocortex and cerebellar cortex. The temporal expression profiles of clock genes are similar in the neocortex and cerebellum, but they are delayed by 5 h as compared to the SCN, suggestively reflecting a master-slave relationship between the SCN and extra-hypothalamic oscillators. Furthermore, ARNTL protein products are detectable in neurons of the mouse neocortex and cerebellum, as revealed by immunohistochemistry. These findings give reason to further pursue the physiological significance of circadian oscillators in the mouse neocortex and cerebellum.

  1. Perinatal exposure to low-dose methylmercury induces dysfunction of motor coordination with decreases in synaptophysin expression in the cerebellar granule cells of rats.

    Science.gov (United States)

    Fujimura, Masatake; Cheng, Jinping; Zhao, Wenchang

    2012-06-29

    Methylmercury (MeHg) is an environmental pollutant that is toxic to the developing central nervous system (CNS) in children, even at low exposure levels. Perinatal exposure to MeHg is known to induce neurological symptoms with neuropathological changes in the CNS. However, the relationship between the neurological symptoms and neuropathological changes induced in offspring as a result of exposure to low-dose MeHg is not well defined. In the present study, neurobehavioral analyses revealed that exposure to a low level of MeHg (5 ppm in drinking water) during developmental caused a significant deficit in the motor coordination of rats in the rotating rod test. In contrast, general neuropathological findings, including neuronal cell death and the subsequent nerve inflammation, were not observed in the region of the cerebellum responsible for regulating motor coordination. Surprisingly, the expression of synaptophysin (SPP), a marker protein for synaptic formation, significantly decreased in cerebellar granule cells. These results showed that perinatal exposure to low-dose MeHg causes neurobehavioral impairment without general neuropathological changes in rats. We demonstrated for the first time that exposure to low-dose MeHg during development induces the dysfunction of motor coordination due to changes of synaptic homeostasis in cerebellar granule cells.

  2. Case of subacute cerebellar degeneration associated with pleocytosis and cerebellar swelling shown in computed tomography scanning

    Energy Technology Data Exchange (ETDEWEB)

    Yoshino, Hiide; Anezaki, Toshiharu; Takashima, Noriko; Inuzuka, Takashi; Miyatake, Tadashi

    1988-02-01

    A 44 year old woman was healthy until January 3, 1986, when she had headache. On January 9, she developed gait ataxia and dysarthria. Cerebellar ataxia worsened rapidly. Aftar a week she could not sit without support and her consciousness was disturbed. Corticosteroid was administrated and consciousness proved alert, but cerebellar ataxia and dysarthria remained unchanged. The patient was found carcinoma of the lung in August 1986. Characteristic features of clinical and laboratory findings of this patient are acute progression, cerebrospinal fluid pleocytosis of 1,064/3 cells (860 mononuclear cell, 204 polymorphonuclear cell), and cerebellar swelling shown in computed tomography scanning. Though the mechanism of acute cerebellar degeneration is still uncertained, inflammatory process was supported to exist in cerebellum of this case.

  3. GABA agonist induced changes in ultrastructure and GABA receptor expression in cerebellar granule cells is linked to hyperpolarization of the neurons

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, G H; Schousboe, A

    1990-01-01

    GABA has been shown to exert a neurotrophic like activity by enhancing the morphological and functional maturation of neurons. Mechanisms involved in this effect of GABA are largely unknown but since GABA has been shown to mediate a hyperpolarizing action on neurons it can be assumed...... that this action might be important. In order to investigate this possibility, the ability to mimic the trophic actions of GABA of different agents known to influence the membrane potential or the GABA gated chloride channels was studied. Hence, GABA receptor expression as well as the ultrastructure of cerebellar...... granule cells were monitored after exposure of the cells in culture to either bromide, valinomycin or picrotoxin. It was found that cells which at early developmental stages (4 days in culture) were exposed to bromide or valinomycin expressed low affinity GABA receptors similar to cells treated...

  4. Lack of Rb and p53 delays cerebellar development and predisposes to large cell anaplastic medulloblastoma through amplification of N-Myc and Ptch2.

    Science.gov (United States)

    Shakhova, Olga; Leung, Carly; van Montfort, Erwin; Berns, Anton; Marino, Silvia

    2006-05-15

    Medulloblastomas are among the most common malignant brain tumors in childhood. They typically arise from neoplastic transformation of granule cell precursors in the cerebellum via deregulation of molecular pathways involved in normal cerebellar development. In a mouse model, we show here that impairment of the balance between proliferation and differentiation of granule cell precursors in the external granular layer of the developing cerebellum predisposes but is not sufficient to induce neoplastic transformation of these progenitor cells. Using array-based chromosomal comparative genomic hybridization, we show that genetic instability resulting from inactivation of the p53 pathway together with deregulation of proliferation induced by Rb loss eventually leads to neoplastic transformation of these cells by acquiring additional genetic mutations, mainly affecting N-Myc and Ptch2 genes. Moreover, we show that p53 loss influences molecular mechanisms that cannot be mimicked by the loss of either p19(ARF), p21, or ATM.

  5. The long adventurous journey of rhombic lip cells in jawed vertebrates: a comparative developmental analysis

    Directory of Open Access Journals (Sweden)

    Mario F Wullimann

    2011-04-01

    Full Text Available This review summarizes vertebrate rhombic lip and early cerebellar development covering classic approaches up to modern developmental genetics which identifies the relevant differential gene expression domains and their progeny. Most of this information is derived from amniotes. However, progress in anamniotes, particularly in the zebrafish, has recently been made. The current picture suggests that rhombic lip and cerebellar development in jawed vertebrates (gnathostomes share many characteristics. Regarding cerebellar development, these include a ptf1a expressing ventral cerebellar proliferation (VCP giving rise to Purkinje cells and other inhibitory cerebellar cell types, and an atoh1 expressing upper rhombic lip giving rise to an external granular layer (EGL, i.e., excitatory granule cells and an early ventral migration into the anterior rhombencephalon (cholinergic nuclei. As for the lower rhombic lip (LRL, gnathostome commonalities likely include the formation of precerebellar nuclei (mossy fiber origins and partially primary auditory nuclei (likely convergently evolved from the atoh1 expressing dorsal zone. The fate of the ptf1a expressing ventral LRL zone which gives rise to (excitatory cells of the inferior olive (climbing fiber origin and (inhibitory cells of cochlear nuclei in amniotes, has not been determined in anamniotes. Special for the zebrafish in comparison to amniotes is the predominant origin of anamniote excitatory deep cerebellar nuclei homologues (i.e., eurydendroid cells from ptf1a expressing VCP cells, the sequential activity of various atoh1 paralogues and the incomplete coverage of the subpial cerebellar plate with proliferative EGL cells. Nevertheless, the conclusion that a rhombic lip and its major derivatives evolved with gnathostome vertebrates only and are thus not an ancestral craniate character complex is supported by the absence of a cerebellum (and likely absence of its afferent and efferent nuclei in jawless

  6. Anticonvulsive Activity in Audiogenic DBA/2 Mice of 1,4-Benzodiazepines and 1,5-Benzodiazepines with Different Activities at Cerebellar Granule Cell GABAA Receptors.

    Science.gov (United States)

    Gatta, Elena; Cupello, Aroldo; Di Braccio, Mario; Grossi, Giancarlo; Robello, Mauro; Scicchitano, Francesca; Russo, Emilio; De Sarro, Giovambattista

    2016-12-01

    Herein, we tested in a model of generalized reflex epilepsy in mice different 1,4-benzodiazepines and 1,5-benzodiazepines with agonistic activity at the GABAA receptor population contributing to the peak component of the chloride current elicited by GABA in cerebellar granule cells (CGCs) in culture. The substances have all higher lipophilia than clobazam, an antiepileptic drug well known and used in human therapy. This ensures that they all can pass relatively easily the blood-brain barrier (BBB). The benzodiazepines were administered intraperitoneally (i.p.) and tested for their activity against sound-induced tonic and clonic seizures in a genetic model of experimental epilepsy, the DBA/2 mouse. Our data demonstrates an interesting inverse correlation between the ED50s and the efficacy (E %) of the drugs in increasing the peak chloride current elicited by GABA in cerebellar granule cells in culture. There is indication of the existence of a threshold of E % above which the increase of ED50 with increasing E % becomes linear. This is statistically significant for the clonic phase, whereas it is at the limit of significance for the tonic one. A possible interpretation of these results is that in this epilepsy model, projections from the cerebellum exert a convulsion prevention activity.

  7. Iatrogenic postoperative cerebellar cyst.

    Science.gov (United States)

    Sharif, Robin; Moscovici, Samuel; Wygoda, Marc; Eliahou, Ruth; Spektor, Sergey

    2016-12-01

    Cerebellar cyst is a known but uncommon entity. It is congenital in most cases, or may develop after brain parenchyma injuries or interventions. To our knowledge, de novo cerebellar cyst after extra-axial tumor excision, has not been described in the literature. We present the first reported case of a de novo cerebellar cyst developing in a 70-year-old woman following retrosigmoid craniotomy for vestibular schwannoma excision, and discuss the possible causes. Following cyst fenestration, there was no clinical or radiological evidence of a residual cyst.

  8. Effect of a GABA agonist on the expression and distribution of GABAA receptors in the plasma membrane of cultured cerebellar granule cells: an immunocytochemical study

    DEFF Research Database (Denmark)

    Hansen, G H; Belhage, B; Schousboe, A

    1991-01-01

    The effect of the gamma-aminobutyric acid (GABA) agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP, 150 microM) on the localization and density of GABAA receptors in the plasma membrane of rat cerebellar granule cells in primary cultures was studied at the electron microscope (EM) level...... by preembedding immunogold staining using the monoclonal antibody bd-17 directed against the beta-subunit of the GABAA receptor complex. In THIP-treated as well as untreated control cultures, GABAA receptors were found to be evenly distributed in the plasma membrane of cell bodies as well as processes. However...... at the EM level using the preembedding immunogold technique. It is likely that low-affinity GABAA receptors are preferentially located in the cell processes and to a considerable extent in the form of 'hot spots'. However, these 'hot spots' also contain high-affinity receptors....

  9. Nitric oxide regulates input specificity of long-term depression and context dependence of cerebellar learning.

    Directory of Open Access Journals (Sweden)

    Hideaki Ogasawara

    2007-01-01

    Full Text Available Recent studies have shown that multiple internal models are acquired in the cerebellum and that these can be switched under a given context of behavior. It has been proposed that long-term depression (LTD of parallel fiber (PF-Purkinje cell (PC synapses forms the cellular basis of cerebellar learning, and that the presynaptically synthesized messenger nitric oxide (NO is a crucial "gatekeeper" for LTD. Because NO diffuses freely to neighboring synapses, this volume learning is not input-specific and brings into question the biological significance of LTD as the basic mechanism for efficient supervised learning. To better characterize the role of NO in cerebellar learning, we simulated the sequence of electrophysiological and biochemical events in PF-PC LTD by combining established simulation models of the electrophysiology, calcium dynamics, and signaling pathways of the PC. The results demonstrate that the local NO concentration is critical for induction of LTD and for its input specificity. Pre- and postsynaptic coincident firing is not sufficient for a PF-PC synapse to undergo LTD, and LTD is induced only when a sufficient amount of NO is provided by activation of the surrounding PFs. On the other hand, above-adequate levels of activity in nearby PFs cause accumulation of NO, which also allows LTD in neighboring synapses that were not directly stimulated, ruining input specificity. These findings lead us to propose the hypothesis that NO represents the relevance of a given context and enables context-dependent selection of internal models to be updated. We also predict sparse PF activity in vivo because, otherwise, input specificity would be lost.

  10. Developmental analysis of the external granular layer in the meander tail mutant mouse: do cerebellar microneurons have independent progenitors?

    Science.gov (United States)

    Napieralski, J A; Eisenman, L M

    1993-08-01

    The cerebellum of the meander tail mutant mouse (mea/mea) is characterized by an apparently normal cytoarchitecture posteriorly with an abrupt transition to an abnormal anterior region. Anteriorly, there is abnormal foliation, a drastic reduction in the granule cells (GC) population, disorganization of the Purkinje cells (PC), and a virtual absence of Bergmann glial processes. In this paper we analyze the prenatal and postnatal development of the cerebellum in the mea/mea and attempt to determine the phenotypic onset of the mutation in the anterior region. Hematoxylin and eosin stained sections reveal a morphological difference in the cerebellum of the mea/mea as early as embryonic day 16 characterized by a reduction in the external granule cell layer (EGL). The reduction in the EGL becomes increasingly apparent as development proceeds. This deficit in the EGL most probably results in the absence of GC, but it is unclear at this point whether reduced migration, proliferation, and/or increased cell death is the major factor. Interestingly, immunohistochemical staining with a monoclonal antibody against parvalbumin reveals that the basket and stellate cells, which are also thought to arise from the EGL, are present in the anterior region of the mea/mea cerebellum. These results suggest that the lack of GC in the meander tail is due to an early expressed abnormality of the EGL. However, the presence of the basket and/or stellate cells raises some interesting questions concerning the lineage of the cerebellar microneurons.

  11. Excitotoxic death induced by released glutamate in depolarized primary cultures of mouse cerebellar granule cells is dependent on GABAA receptors and niflumic acid-sensitive chloride channels.

    Science.gov (United States)

    Babot, Zoila; Cristòfol, Rosa; Suñol, Cristina

    2005-01-01

    Excitotoxic neuronal death has been linked to neurological and neurodegenerative diseases. Several studies have sought to clarify the involvement of Cl(-) channels in neuronal excitotoxicity using either N-methyl-D-aspartic acid (NMDA) or alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate/kainic acid agonists. In this work we induced excitotoxic death in primary cultures of cerebellar granule cells by means of endogenously released glutamate. Excitotoxicity was provoked by exposure to high extracellular K(+) concentrations ([K(+)](o)) for 5 min. Under these conditions, a Ca(2+)-dependent release of glutamate was evoked. When extracellular glutamate concentration rose to between 2 and 4 microM, cell viability was significantly reduced by 30-40%. The NMDA receptor antagonists (MK-801 and D-2-amino-5-phosphonopentanoic acid) prevented cell death. Exposure to high [K(+)](o) produced a (36)Cl(-) influx which was significantly reduced by picrotoxinin. In addition, the GABA(A) receptor antagonists (bicuculline, picrotoxinin and SR 95531) protected cells from high [K(+)](o)-triggered excitotoxicity and reduced extracellular glutamate concentration. The Cl(-) channel blockers niflumic acid and 5-nitro-2-(3-phenylpropylamino)benzoic acid also exerted a neuroprotective effect and reduced extracellular glutamate concentration, even though they did not reduce high [K(+)](o)-induced (36)Cl(-) influx. Primary cultures of cerebellar granule cells also contain a population of GABAergic neurons that released GABA in response to high [K(+)](o). Chronic treatment of primary cultures with kainic acid abolished GABA release and rendered granule cells insensitive to high [K(+)](o) exposure, even though NMDA receptors were functional. Altogether, these results demonstrate that, under conditions of membrane depolarization, low micromolar concentrations of extracellular glutamate might induce an excitotoxic process through both NMDA and GABA(A) receptors and niflumic acid-sensitive Cl

  12. HISTOCHEMICAL STUDY OF THE AFFECTION OF TEMPORARY CEREBRAL ISCHEMIA ON THE CEREBELLAR CORTEX%短暂性缺血对小脑皮质影响的组织化学研究

    Institute of Scientific and Technical Information of China (English)

    李仁; 顾远清; 陈显斌; 李昊; 熊希凯; 吴刚

    2001-01-01

    In order to explore the affection of temporary cerebral ischemiaon the purkinje cells of the cerebellary cortex. Using histochemical method, enzymehistochemical changes was observed in the purkinje cells of the rabbit after ischemia of 5 minutes (group B)、 10 minutes (group C) and reperfusion (group D、E). The results showed that after 10 minutes of ischemia and reperfusion. The activites of SDH、Mg2+-ATP、PAS were reduced (P<0.05), While the activites of LDH wre increased (P<0.01). The results suggested that the injury of 10 minutes ischemia and reperfusion may damage the activites of enzymes associated with energic metabolism in cerebellar cortex of purkinje cells.%为了探讨全脑短暂性缺血对小脑皮质蒲肯野细胞的影响,实验用组织化学方法对家兔全脑缺血5分钟(B组)、10分钟(C组)及缺血再灌(D、E组)后蒲肯野细胞的酶组织化学变化进行了观察。结果显示,缺血10分钟及缺血再灌后蒲肯野细胞的SDH、Mg2+-ATP活性及PAS反应均降低(P<0.05),LDH增高(P<0.01)。结果提示家兔全脑缺血10分钟和缺血再灌可损害小脑皮质蒲肯野细胞的能量代谢酶的活性。

  13. A SEL1L mutation links a canine progressive early-onset cerebellar ataxia to the endoplasmic reticulum-associated protein degradation (ERAD machinery.

    Directory of Open Access Journals (Sweden)

    Kaisa Kyöstilä

    Full Text Available Inherited ataxias are characterized by degeneration of the cerebellar structures, which results in progressive motor incoordination. Hereditary ataxias occur in many species, including humans and dogs. Several mutations have been found in humans, but the genetic background has remained elusive in dogs. The Finnish Hound suffers from an early-onset progressive cerebellar ataxia. We have performed clinical, pathological, and genetic studies to describe the disease phenotype and to identify its genetic cause. Neurological examinations on ten affected dogs revealed rapidly progressing generalized cerebellar ataxia, tremors, and failure to thrive. Clinical signs were present by the age of 3 months, and cerebellar shrinkage was detectable through MRI. Pathological and histological examinations indicated cerebellum-restricted neurodegeneration. Marked loss of Purkinje cells was detected in the cerebellar cortex with secondary changes in other cortical layers. A genome-wide association study in a cohort of 31 dogs mapped the ataxia gene to a 1.5 Mb locus on canine chromosome 8 (p(raw = 1.1x10(-7, p(genome = 7.5x10(-4. Sequencing of a functional candidate gene, sel-1 suppressor of lin-12-like (SEL1L, revealed a homozygous missense mutation, c.1972T>C; p.Ser658Pro, in a highly conserved protein domain. The mutation segregated fully in the recessive pedigree, and a 10% carrier frequency was indicated in a population cohort. SEL1L is a component of the endoplasmic reticulum (ER-associated protein degradation (ERAD machinery and has not been previously associated to inherited ataxias. Dysfunctional protein degradation is known to cause ER stress, and we found a significant increase in expression of nine ER stress responsive genes in the cerebellar cortex of affected dogs, supporting the pathogenicity of the mutation. Our study describes the first early-onset neurodegenerative ataxia mutation in dogs, establishes an ERAD-mediated neurodegenerative

  14. Developmental exposure to ethanol increases the neuronal vulnerability to oxygen-glucose deprivation in cerebellar granule cell cultures.

    Science.gov (United States)

    Le Duc, Diana; Spataru, Ana; Ceanga, Mihai; Zagrean, Leon; Schöneberg, Torsten; Toescu, Emil C; Zagrean, Ana-Maria

    2015-07-21

    Prenatal alcohol exposure is associated with microencephaly, cognitive and behavioral deficits, and growth retardation. Some of the mechanisms of ethanol-induced injury, such as high level oxidative stress and overexpression of pro-apoptotic genes, can increase the sensitivity of fetal neurons towards hypoxic/ischemic stress associated with normal labor. Thus, alcohol-induced sequelae may be the cumulative result of direct ethanol toxicity and increased neuronal vulnerability towards metabolic stressors, including hypoxia. We examined the effects of ethanol exposure on the fetal cerebellar granular neurons' susceptibility to hypoxic/hypoglycemic damage. A chronic ethanol exposure covered the entire prenatal period and 5 days postpartum through breastfeeding, a time interval partially extending into the third-trimester equivalent in humans. After a binge-like alcohol exposure at postnatal day 5, glutamatergic cerebellar granule neurons were cultured and grown for 7 days in vitro, then exposed to a 3-h oxygen-glucose deprivation to mimic a hypoxic/ischemic condition. Cellular viability was monitored by dynamic recording of propidium iodide fluorescence over 20 h reoxygenation. We explored differentially expressed genes on microarray data from a mouse embryonic ethanol-exposure model and validated these by real-time PCR on the present model. In the ethanol-treated cerebellar granule neurons we find an increased expression of genes related to apoptosis (Mapk8 and Bax), but also of genes previously described as neuroprotective (Dhcr24 and Bdnf), which might suggest an actively maintained viability. Our data suggest that neurons exposed to ethanol during development are more vulnerable to in vitro hypoxia/hypoglycemia and have higher intrinsic death susceptibility than unexposed neurons.

  15. Effect of a GABA agonist on the expression and distribution of GABAA receptors in the plasma membrane of cultured cerebellar granule cells: an immunocytochemical study

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Belhage, B; Schousboe, A

    1991-01-01

    , the density of the GABAA receptors was significantly increased in the THIP-treated cultures as compared to the control cultures and this effect of THIP was particularly pronounced in the processes. GABAA receptors were occasionally observed to form 'hot spots' in process-like structures and again......The effect of the gamma-aminobutyric acid (GABA) agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP, 150 microM) on the localization and density of GABAA receptors in the plasma membrane of rat cerebellar granule cells in primary cultures was studied at the electron microscope (EM) level...... by preembedding immunogold staining using the monoclonal antibody bd-17 directed against the beta-subunit of the GABAA receptor complex. In THIP-treated as well as untreated control cultures, GABAA receptors were found to be evenly distributed in the plasma membrane of cell bodies as well as processes. However...

  16. A Computational Model for the AMPA Receptor Phosphorylation Master Switch Regulating Cerebellar Long-Term Depression.

    Directory of Open Access Journals (Sweden)

    Andrew R Gallimore

    2016-01-01

    Full Text Available The expression of long-term depression (LTD in cerebellar Purkinje cells results from the internalisation of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs from the postsynaptic membrane. This process is regulated by a complex signalling pathway involving sustained protein kinase C (PKC activation, inhibition of serine/threonine phosphatase, and an active protein tyrosine phosphatase, PTPMEG. In addition, two AMPAR-interacting proteins-glutamate receptor-interacting protein (GRIP and protein interacting with C kinase 1 (PICK1-regulate the availability of AMPARs for trafficking between the postsynaptic membrane and the endosome. Here we present a new computational model of these overlapping signalling pathways. The model reveals how PTPMEG cooperates with PKC to drive LTD expression by facilitating the effect of PKC on the dissociation of AMPARs from GRIP and thus their availability for trafficking. Model simulations show that LTD expression is increased by serine/threonine phosphatase inhibition, and negatively regulated by Src-family tyrosine kinase activity, which restricts the dissociation of AMPARs from GRIP under basal conditions. We use the model to expose the dynamic balance between AMPAR internalisation and reinsertion, and the phosphorylation switch responsible for the perturbation of this balance and for the rapid plasticity initiation and regulation. Our model advances the understanding of PF-PC LTD regulation and induction, and provides a validated extensible platform for more detailed studies of this fundamental synaptic process.

  17. Fast convergence of learning requires plasticity between inferior olive and deep cerebellar nuclei in a manipulation task: a closed-loop robotic simulation.

    Science.gov (United States)

    Luque, Niceto R; Garrido, Jesús A; Carrillo, Richard R; D'Angelo, Egidio; Ros, Eduardo

    2014-01-01

    The cerebellum is known to play a critical role in learning relevant patterns of activity for adaptive motor control, but the underlying network mechanisms are only partly understood. The classical long-term synaptic plasticity between parallel fibers (PFs) and Purkinje cells (PCs), which is driven by the inferior olive (IO), can only account for limited aspects of learning. Recently, the role of additional forms of plasticity in the granular layer, molecular layer and deep cerebellar nuclei (DCN) has been considered. In particular, learning at DCN synapses allows for generalization, but convergence to a stable state requires hundreds of repetitions. In this paper we have explored the putative role of the IO-DCN connection by endowing it with adaptable weights and exploring its implications in a closed-loop robotic manipulation task. Our results show that IO-DCN plasticity accelerates convergence of learning by up to two orders of magnitude without conflicting with the generalization properties conferred by DCN plasticity. Thus, this model suggests that multiple distributed learning mechanisms provide a key for explaining the complex properties of procedural learning and open up new experimental questions for synaptic plasticity in the cerebellar network.

  18. Modeling tissue- and mutation- specific electrophysiological effects in the long QT syndrome: role of the Purkinje fiber.

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    Vivek Iyer

    Full Text Available Congenital long QT syndrome is a heritable family of arrhythmias caused by mutations in 13 genes encoding ion channel complex proteins. Mounting evidence has implicated the Purkinje fiber network in the genesis of ventricular arrhythmias. In this study, we explore the hypothesis that long QT mutations can demonstrate different phenotypes depending on the tissue type of expression. Using computational models of the human ventricular myocyte and the Purkinje fiber cell, the biophysical alteration in channel function in LQT1, LQT2, LQT3, and LQT7 are modeled. We identified that the plateau potential was important in LQT1 and LQT2, in which mutation led to minimal action potential prolongation in Purkinje fiber cells. The phenotype of LQT3 mutation was dependent on the biophysical alteration induced as well as tissue type. The canonical ΔKPQ mutation causes severe action potential prolongation in both tissue types. For LQT3 mutation F1473C, characterized by shifted channel availability, a more severe phenotype was seen in Purkinje fiber cells with action potential prolongation and early afterdepolarizations. The LQT3 mutation S1904L demonstrated striking effects on action potential duration restitution and more severe action potential prolongation in Purkinje fiber cells at higher heart rates. Voltage clamp simulations highlight the mechanism of effect of these mutations in different tissue types, and impact of drug therapy is explored. We conclude that arrhythmia formation in long QT syndrome may depend not only on the basis of mutation and biophysical alteration, but also upon tissue of expression. The Purkinje fiber network may represent an important therapeutic target in the management of patients with heritable channelopathies.

  19. Exposure to extremely low-frequency electromagnetic fields modulates Na+ currents in rat cerebellar granule cells through increase of AA/PGE2 and EP receptor-mediated cAMP/PKA pathway.

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    Yan-Lin He

    Full Text Available Although the modulation of Ca(2+ channel activity by extremely low-frequency electromagnetic fields (ELF-EMF has been studied previously, few reports have addressed the effects of such fields on the activity of voltage-activated Na(+ channels (Na(v. Here, we investigated the effects of ELF-EMF on Na(v activity in rat cerebellar granule cells (GCs. Our results reveal that exposing cerebellar GCs to ELF-EMF for 10-60 min significantly increased Na(v currents (I(Na by 30-125% in a time- and intensity-dependent manner. The Na(v channel steady-state activation curve, but not the steady-state inactivation curve, was significantly shifted (by 5.2 mV towards hyperpolarization by ELF-EMF stimulation. This phenomenon is similar to the effect of intracellular application of arachidonic acid (AA and prostaglandin E(2 (PGE(2 on I(Na in cerebellar GCs. Increases in intracellular AA, PGE(2 and phosphorylated PKA levels in cerebellar GCs were observed following ELF-EMF exposure. Western blottings indicated that the Na(V 1.2 protein on the cerebellar GCs membrane was increased, the total expression levels of Na(V 1.2 protein were not affected after exposure to ELF-EMF. Cyclooxygenase inhibitors and PGE(2 receptor (EP antagonists were able to eliminate this ELF-EMF-induced increase in phosphorylated PKA and I(Na. In addition, ELF-EMF exposure significantly enhanced the activity of PLA(2 in cerebellar GCs but did not affect COX-1 or COX-2 activity. Together, these data demonstrate for the first time that neuronal I(Na is significantly increased by ELF-EMF exposure via a cPLA2 AA PGE(2 EP receptors PKA signaling pathway.

  20. Effects of inhibitors of protein synthesis and intracellular transport on the gamma-aminobutyric acid agonist-induced functional differentiation of cultured cerebellar granule cells

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, G H; Meier, E;

    1990-01-01

    differentiation and GABA receptor expression was investigated in cultured cerebellar granule cells. After 4 days in culture the neurons were exposed to the inhibitors for 6 h in the simultaneous presence of THIP. Subsequently, cultures were either fixed for electron microscopic examination or used for preparation...... of membranes for [3H]GABA binding assays. In some experiments the functional activity of the newly induced low-affinity GABA receptors was assessed by investigation of the ability of GABA to inhibit neurotransmitter release from the neurons. These experiments were performed to differentiate between...... an intracellular and a plasma membrane localization of the receptors. In all experiments cultures treated with THIP alone served as controls. The inhibitors of protein synthesis totally abolished the ability of THIP to induce low-affinity GABA receptors. In contrast, the inhibitors of intracellular transport...

  1. TGFβ1 downregulates neurite outgrowth, expression of Ca2+ transporters, and mitochondrial dynamics of in vitro cerebellar granule cells.

    Science.gov (United States)

    Jaskova, Katarina; Pavlovicova, Michaela; Cagalinec, Michal; Lacinova, Lubica; Jurkovicova, Dana

    2014-03-26

    Acute injury to central nervous system (CNS) triggers neurodegenerative processes that can result in serious damage or complete loss of function. After injury, production of transforming growth factor β1 (TGFβ1) increases and initiates creation of a fibrotic scar that prevents normal growth, plasticity, and recovery of damaged neurons. Administration of TGFβ1 antagonists can prevent its pathological effects. To define consequences of increased TGFβ1 release on calcium signaling, neuronal plasticity, excitability, and mitochondrial dynamics in CNS neurons we directly exposed a rat primary culture of cerebellar granule neurons to TGFβ1. We focused on changes in expression of intracellular calcium transporters, especially inositol-1,4,5-trisphosphate receptor (IP3R) type 1, mitochondrial dynamics, and membrane excitability. TGFβ1 significantly decreased the gene and protein expression of inositol-1,4,5-trisphosphate receptor type 1 and the gene expression of additional intracellular Ca transporters such as IP3R2, ryanodine receptor type 1 (RyR1), RyR2, and SERCA2. Altered calcium signaling suppressed neurite outgrowth and significantly decreased the length of the mitochondria and the frequency of mitochondrial fusion. The resting membrane potential of cerebellar granule neurons was hyperpolarized and slow after depolarization of single action potential was suppressed. LY364947, a blocker of TGFβ1 receptor I, prevented these effects, and IP3 receptor blocker 2-aminoethoxydiphenyl borate (2APB) mimicked them. After CNS injury TGFβ1 downregulates intracellular Ca levels and alters Ca signaling within injured neurons. We suggest that in our model TGFβ1 may trigger both neurodegenerative and neuroprotective events through IP3-induced Ca signaling.

  2. Cerebellar anatomy as applied to cerebellar microsurgical resections

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    Alejandro Ramos

    2012-06-01

    Full Text Available OBJECTIVE: To define the anatomy of dentate nucleus and cerebellar peduncles, demonstrating the surgical application of anatomic landmarks in cerebellar resections. METHODS: Twenty cerebellar hemispheres were studied. RESULTS: The majority of dentate nucleus and cerebellar peduncles had demonstrated constant relationship to other cerebellar structures, which provided landmarks for surgical approaching. The lateral border is separated from the midline by 19.5 mm in both hemispheres. The posterior border of the cortex is separated 23.3 mm from the posterior segment of the dentate nucleus; the lateral one is separated 26 mm from the lateral border of the nucleus; and the posterior segment of the dentate nucleus is separated 25.4 mm from the posterolateral angle formed by the junction of lateral and posterior borders of cerebellar hemisphere. CONCLUSIONS: Microsurgical anatomy has provided important landmarks that could be applied to cerebellar surgical resections.

  3. Differential Modulation of GABAA Receptors Underlies Postsynaptic Depolarization- and Purinoceptor-Mediated Enhancement of Cerebellar Inhibitory Transmission: A Non-Stationary Fluctuation Analysis Study

    Science.gov (United States)

    Ono, Yumie; Saitow, Fumihito; Konishi, Shiro

    2016-01-01

    Cerebellar GABAergic inhibitory transmission between interneurons and Purkinje cells (PCs) undergoes a long-lasting enhancement following different stimulations, such as brief depolarization or activation of purinergic receptors of postsynaptic PCs. The underlying mechanisms, however, are not completely understood. Using a peak-scaled non-stationary fluctuation analysis, we therefore aimed at characterizing changes in the electrophysiological properties of GABAA receptors in PCs of rat cerebellar cortex during depolarization-induced “rebound potentiation (RP)” and purinoceptor-mediated long-term potentiation (PM-LTP), because both RP and PM-LTP likely depend on postsynaptic mechanisms. Stimulation-evoked inhibitory postsynaptic currents (eIPSCs) were recorded from PCs in neonatal rat cerebellar slices. Our analysis showed that postsynaptic membrane depolarization induced RP of eIPSCs in association with significant increase in the number of synaptic GABAA receptors without changing the channel conductance. By contrast, bath application of ATP induced PM-LTP of eIPSCs with a significant increase of the channel conductance of GABAA receptors without affecting the receptor number. Pretreatment with protein kinase A (PKA) inhibitors, H-89 and cAMPS-Rp, completely abolished the PM-LTP. The CaMKII inhibitor KN-62 reported to abolish RP did not alter PM-LTP. These results suggest that the signaling mechanism underlying PM-LTP could involve ATP-induced phosphorylation of synaptic GABAA receptors, thereby resulting in upregulation of the channel conductance by stimulating adenylyl cyclase-PKA signaling cascade, possibly via activation of P2Y11 purinoceptor. Thus, our findings reveal that postsynaptic GABAA receptors at the interneuron-PC inhibitory synapses are under the control of two distinct forms of long-term potentiation linked with different second messenger cascades. PMID:26930485

  4. Cerebellar Hypoplasia and Autism

    OpenAIRE

    1989-01-01

    The size of the cerebellar hemisphere and vermal lobules was measured in ten autistic and eight normal control subjects at the Neuropsychology Research Laboratory, Children’s Hospital Research Center, and the Departments of Neurosciences and Radiology, School of Medicine, University of California at San Diego, LaJolla.

  5. Effects of differential interference with postnatal cerebellar neurogenesis on motor performance, activity level, and maze learning of rats: a developmental study.

    Science.gov (United States)

    Pellegrino, L J; Altman, J

    1979-02-01

    The region of the cerebellum was X-irradiated in infant rats with selected exposure schedules designed to produce animals in which the cerebellar cortex was (a) essentially normal except for agenesis of late forming granule cells with axons situated in the uppermost molecular layer (12--15X), (b) lacking in stellate cells, with a severe reduction in granule cells with axons in the upper molecular layer (8--15X), (c) morphologically disorganized but had only intermediate cell agenesis (4--5X), or (d) disorganized and devoid of practically all postnatally forming interneurons (4--15X). In the first two experiments young adults had to traverse rotating rods that differed in texture and types of obstacles. The 8--15X animals showed no deficits on any of the rods tested. The third study dealt with spontaneous motor performance in the open field at three ages. The 4--5X and 4--15X animals were hypoactive as infants and young adults; this was attributed to their motor deficits. The 8--15X and 12--15X animals were hyperactive in the open field as young adults. The fourth experiment examined intra- and/or intersession habituation. No group differences were found in habituation patterns. In the fifth experiment, using activity wheels, the 4--15X group was hypoactive, and the 8--15X and 12--15X groups were hyperactive as young adults. In the sixth experiment young adults were tested for learning performance in a multiple-unit water maze. The 4--15X group was deficient on single alternation; the 4--5X and 12--15X groups on double alternation. The seventh experiment shed some light on the single alternation deficit of the 4--15X group; only these animals failed to alternate spontaneously in a nonaversive situation. In conclusion, these behavioral results, combined with those of recent morphological investigations, suggest that the cerebellar cortex is hierarchically organized: The basal domain of Purkinje cells and the lower molecular layer are implicated in the coordination of

  6. RNA interference mitigates motor and neuropathological deficits in a cerebellar mouse model of Machado-Joseph disease.

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    Clévio Nóbrega

    Full Text Available Machado-Joseph disease or Spinocerebellar ataxia type 3 is a progressive fatal neurodegenerative disorder caused by the polyglutamine-expanded protein ataxin-3. Recent studies demonstrate that RNA interference is a promising approach for the treatment of Machado-Joseph disease. However, whether gene silencing at an early time-point is able to prevent the appearance of motor behavior deficits typical of the disease when initiated before onset of the disease had not been explored. Here, using a lentiviral-mediated allele-specific silencing of mutant ataxin-3 in an early pre-symptomatic cerebellar mouse model of Machado-Joseph disease we show that this strategy hampers the development of the motor and neuropathological phenotypic characteristics of the disease. At the histological level, the RNA-specific silencing of mutant ataxin-3 decreased formation of mutant ataxin-3 aggregates, preserved Purkinje cell morphology and expression of neuronal markers while reducing cell death. Importantly, gene silencing prevented the development of impairments in balance, motor coordination, gait and hyperactivity observed in control mice. These data support the therapeutic potential of RNA interference for Machado-Joseph disease and constitute a proof of principle of the beneficial effects of early allele-specific silencing for therapy of this disease.

  7. Optimization of single-cell electroporation protocol for forced gene expression in primary neuronal cultures.

    Science.gov (United States)

    Nishikawa, Shin; Hirashima, Naohide; Tanaka, Masahiko

    2014-09-01

    The development and function of the central nervous system (CNS) are realized through interactions between many neurons. To investigate cellular and molecular mechanisms of the development and function of the CNS, it is thus crucial to be able to manipulate the gene expression of single neurons in a complex cell population. We recently developed a technique for gene silencing by introducing small interfering RNA into single neurons in primary CNS cultures using single-cell electroporation. However, we had not succeeded in forced gene expression by introducing expression plasmids using single-cell electroporation. In the present study, we optimized the experimental conditions to enable the forced expression of green fluorescent protein (GFP) in cultured cerebellar Purkinje neurons using single-cell electroporation. We succeeded in strong GFP expression in Purkinje neurons by increasing the inside diameter of micropipettes or by making the size of the original plasmid smaller by digestion and cyclizing it by ligation. Strong GFP expression in Purkinje neurons electroporated under the optimal conditions continued to be observed for more than 25 days after electroporation. Thus, this technique could be used for forced gene expression in single neurons to investigate cellular and molecular mechanisms of the development, function, and disease of the CNS.

  8. Acute NMDA toxicity in cultured rat cerebellar granule neurons is accompanied by autophagy induction and late onset autophagic cell death phenotype

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    Kobeissy Firas H

    2010-02-01

    Full Text Available Abstract Background Autophagy, an intracellular response to stress, is characterized by double membrane cytosolic vesicles called autophagosomes. Prolonged autophagy is known to result in autophagic (Type II cell death. This study examined the potential role of an autophagic response in cultured cerebellar granule neurons challenged with excitotoxin N-methyl-D-aspartate (NMDA. Results NMDA exposure induced light chain-3 (LC-3-immunopositive and monodansylcadaverine (MDC fluorescent dye-labeled autophagosome formation in both cell bodies and neurites as early as 3 hours post-treatment. Elevated levels of Beclin-1 and the autophagosome-targeting LC3-II were also observed following NMDA exposure. Prolonged exposure of the cultures to NMDA (8-24 h generated MDC-, LC3-positive autophagosomal bodies, concomitant with the neurodegenerative phase of NMDA challenge. Lysosomal inhibition studies also suggest that NMDA-treatment diverted the autophagosome-associated LC3-II from the normal lysosomal degradation pathway. Autophagy inhibitor 3-methyladenine significantly reduced NMDA-induced LC3-II/LC3-I ratio increase, accumulation of autophagosomes, and suppressed NMDA-mediated neuronal death. ATG7 siRNA studies also showed neuroprotective effects following NMDA treatment. Conclusions Collectively, this study shows that autophagy machinery is robustly induced in cultured neurons subjected to prolonged exposure to excitotoxin, while autophagosome clearance by lysosomal pathway might be impaired. Our data further show that prolonged autophagy contributes to cell death in NMDA-mediated excitotoxicity.

  9. Effect of benzene on the cerebellar structure and behavioral characteristics in rats

    Institute of Scientific and Technical Information of China (English)

    Ali Rafati; Mahboobeh Erfanizadeh; Ali Noorafshan; Saied Karbalay-Doust

    2015-01-01

    Objective:To investigate the effects of benzene on rat’s cerebellum structure and behavioral characteristics, including anxiety and motor impairment. Methods:Twenty rats were randomly allocated into two groups orally receiving distilled water and benzene (200 mg/kg/day). A total of 10 rats were used at the beginning of benzene exposure. Two rats died during benzene treatment and 8 rats remained for evaluation of the behavioral test and finally 6 rats underwent histological assessment. At the end of the 4th week, motor function and anxiety were evaluated in rotarod test and elevated plus maze, respectively. Besides, the cerebellum was dissected for structural assessment using stereological methods. Results:Performance of the benzene-treated rats in fixed and accelerating speed rotarod was impaired and their riding time (endurance) was lower compared to the control group (P=0.02). The benzene-treated rats also spent less time in the open arms and had fewer entrances to the open arms in comparison to the control group, indicating anxiety (P=0.01). The total volume of the cerebellar hemisphere, its cortex, intracerebellar nuclei, total number of the Purkinje, Bergmann, Golgi, granule, neurons and glial cells of the molecular layer, and neurons and glial cells of the intracerebellar nuclei were reduced by 34%-76%in the benzene-treated rats in comparison to the distilled water group (P=0.003). The most cell loss was seen in Bergmann glia. Conclusions:The structure of cerebellum altered after benzene treatment. In addition, motor impairment and anxiety could be seen in benzene-treated rats.

  10. Effect of benzene on the cerebellar structure and behavioral characteristics in rats

    Institute of Scientific and Technical Information of China (English)

    Ali; Rafati; Mahboobeh; Erfanizadeh; Ali; Noorafshan; Saied; Karbalay-Doust

    2015-01-01

    Objective: To investigate the effects of benzene on rat’s cerebellum structure and behavioral characteristics, including anxiety and motor impairment.Methods: Twenty rats were randomly allocated into two groups orally receiving distilled water and benzene(200 mg/kg/day). A total of 10 rats were used at the beginning of benzene exposure. Two rats died during benzene treatment and 8 rats remained for evaluation of the behavioral test and finally 6 rats underwent histological assessment. At the end of the 4th week, motor function and anxiety were evaluated in rotarod test and elevated plus maze, respectively. Besides, the cerebellum was dissected for structural assessment using stereological methods.Results: Performance of the benzene-treated rats in fixed and accelerating speed rotarod was impaired and their riding time(endurance) was lower compared to the control group(P = 0.02). The benzene-treated rats also spent less time in the open arms and had fewer entrances to the open arms in comparison to the control group, indicating anxiety(P = 0.01). The total volume of the cerebellar hemisphere, its cortex, intracerebellar nuclei, total number of the Purkinje, Bergmann, Golgi, granule, neurons and glial cells of the molecular layer, and neurons and glial cells of the intracerebellar nuclei were reduced by 34%-76% in the benzene-treated rats in comparison to the distilled water group(P = 0.003). The most cell loss was seen in Bergmann glia. Conclusions: The structure of cerebellum altered after benzene treatment. In addition, motor impairment and anxiety could be seen in benzene-treated rats.

  11. Two new cases of anti-Ca (anti-ARHGAP26/GRAF autoantibody-associated cerebellar ataxia

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    Jarius Sven

    2013-01-01

    Full Text Available Abstract Recently, we discovered a novel serum and cerebrospinal fluid (CSF autoantibody (anti-Ca to Purkinje cells in a patient with autoimmune cerebellar ataxia (ACA and identified the RhoGTPase-activating protein 26 (ARHGAP26; alternative designations include GTPase regulator associated with focal adhesion kinase pp125, GRAF, and oligophrenin-1-like protein, OPHN1L as the target antigen. Here, we report on two new cases of ARHGAP26 autoantibody-positive ACA that were first diagnosed after publication of the index case study. While the index patient developed ACA following an episode of respiratory infection with still no evidence for malignancy 52 months after onset, neurological symptoms heralded ovarian cancer in one of the patients described here. Our finding of anti-Ca/anti-ARHGAP26 antibodies in two additional patients supports a role of autoimmunity against ARHGAP26 in the pathogenesis of ACA. Moreover, the finding of ovarian cancer in one of our patients suggests that anti-Ca/anti-ARHGAP26-positive ACA might be of paraneoplastic aetiology in some cases. In conclusion, testing for anti-Ca/anti-ARHGAP26 should be included in the diagnostic work-up of patients with ACA, and an underlying tumour should be considered in patients presenting with anti-Ca/ARHGAP26 antibody-positive ACA.

  12. Genetics Home Reference: lissencephaly with cerebellar hypoplasia

    Science.gov (United States)

    ... Conditions lissencephaly with cerebellar hypoplasia lissencephaly with cerebellar hypoplasia Enable Javascript to view the expand/collapse boxes. ... Open All Close All Description Lissencephaly with cerebellar hypoplasia (LCH) affects brain development, resulting in the brain ...

  13. Specification of spatial identities of cerebellar neuron progenitors by ptf1a and atoh1 for proper production of GABAergic and glutamatergic neurons.

    Science.gov (United States)

    Yamada, Mayumi; Seto, Yusuke; Taya, Shinichiro; Owa, Tomoo; Inoue, Yukiko U; Inoue, Takayoshi; Kawaguchi, Yoshiya; Nabeshima, Yo-Ichi; Hoshino, Mikio

    2014-04-01

    In the cerebellum, the bHLH transcription factors Ptf1a and Atoh1 are expressed in distinct neuroepithelial regions, the ventricular zone (VZ) and the rhombic lip (RL), and are required for producing GABAergic and glutamatergic neurons, respectively. However, it is unclear whether Ptf1a or Atoh1 is sufficient for specifying GABAergic or glutamatergic neuronal fates. To test this, we generated two novel knock-in mouse lines, Ptf1a(Atoh1) and Atoh1(Ptf1a), that are designed to express Atoh1 and Ptf1a ectopically in the VZ and RL, respectively. In Ptf1a(Atoh1) embryos, ectopically Atoh1-expressing VZ cells produced glutamatergic neurons, including granule cells and deep cerebellar nuclei neurons. Correspondingly, in Atoh1(Ptf1a) animals, ectopically Ptf1a-expressing RL cells produced GABAergic populations, such as Purkinje cells and GABAergic interneurons. Consistent results were also obtained from in utero electroporation of Ptf1a or Atoh1 into embryonic cerebella, suggesting that Ptf1a and Atoh1 are essential and sufficient for GABAergic versus glutamatergic specification in the neuroepithelium. Furthermore, birthdating analyses with BrdU in the knock-in mice or with electroporation studies showed that ectopically produced fate-changed neuronal types were generated at temporal schedules closely simulating those of the wild-type RL and VZ, suggesting that the VZ and RL share common temporal information. Observations of knock-in brains as well as electroporated brains revealed that Ptf1a and Atoh1 mutually negatively regulate their expression, probably contributing to formation of non-overlapping neuroepithelial domains. These findings suggest that Ptf1a and Atoh1 specify spatial identities of cerebellar neuron progenitors in the neuroepithelium, leading to appropriate production of GABAergic and glutamatergic neurons, respectively.

  14. Protective effect of keishi-bukuryo-gan and its constituent medicinal plants against nitric oxide donor-induced neuronal death in cultured cerebellar granule cells.

    Science.gov (United States)

    Shimada, Y; Yokoyama, K; Goto, H; Sekiya, N; Mantani, N; Tahara, E; Hikiami, H; Terasawa, K

    2004-07-01

    Keishi-bukuryo-gan (Gui-Zhi-Fu-Ling-Wan) (KBG) is a traditional Chinese/Japanese medical (Kampo) formulation that has been administered to patients with "Oketsu" (blood stagnation) syndrome. In the process of neuronal cell death induced by brain ischemia, excessive generation of nitric oxide (NO) free radicals is implicated in the neurotoxicity. In the present study, we examined the protective effects of KBG and its constituent medicinal plants against NO donors, sodium nitroprusside (SNP) and 2,2'-(hydroxynitrosohydrazino)bis-ethanamine (NOC18)-induced neuronal death in cultured rat cerebellar granule cells (CGCs). MTT assay showed cell viability to be significantly increased by the addition of KBG extract (KBGE) (100 microg/ml), Cinnamomi Cortex extract (CCE) (3, 10 and 30 microg/ml), Paeoniae Radix extract (PRE) (100 microg/ml) and Moutan Cortex extract (MCE) (10 and 30 microg/ml) compared with exposure to SNP (30 microM, 24 h) only. Also, cell viability was significantly increased by the addition of KBGE (100 and 300 microg/ml), CCE (30 and 100 microg/ml), PRE (100 and 300 microg/ml) and MCE (30 and 100 microg/ml) compared with exposure to NOC 18 (100 microM, 48 h) only. Persicae Semen extract and Hoelen extract did not protect against NO donor-induced neuronal death. These results suggest that KBG has protective effect against NO-mediated neuronal death in cultured CGCs and that it is derived from Cinnamomi Cortex, Paeoniae Radix and Moutan Cortex.

  15. Cerebellar Dysfunction in a Patient with HIV.

    Science.gov (United States)

    Gonzalez-Ibarra, Fernando; Abdul, Waheed; Eivaz-Mohammadi, Sahar; Foscue, Christopher; Gongireddy, Srinivas; Syed, Amer

    2014-01-01

    A 50-year-old AIDS patient with a CD4 T-cell count of 114/mm(3) was admitted with cerebellar symptoms of left CN XI weakness, wide-based gait with left-sided dysmetria, abnormal heel-knee-shin test, and dysdiadochokinesia. MRI showed region of hyperintensity in the left inferior cerebellar hemisphere involving the cortex and underlying white matter. Serological tests for HSV1, HSV2, and syphilis were negative. Her CSF contained high protein content and a WBC of 71/mm(3), predominantly lymphocytes. The CSF was also negative for cryptococcal antigen and VDRL. CSF culture did not grow microbes. CSF PCR assay was negative for HSV1 and HSV2 but was positive for JC virus (1,276 copies). The most likely diagnosis is granule cell neuronopathy (GCN), which can only be definitively confirmed with biopsy and immunohistochemistry.

  16. 出生前接触酒精对大鼠小脑中BDNF和TrkB的影响%EFFECTS OF PRENATAL ALCOHOL EXPOSURE ON BDNF - AND TRKB IN THE RAT CERE-BELLAR CORTEX

    Institute of Scientific and Technical Information of China (English)

    金福; 李今子; 池永学; 李红子; 魏宝玉; 苏立明

    2011-01-01

    [Objective] To investigate the changes of BDNF- and TrkB in the rat cerebellar cortex with prenatal alcohol exposure. [Methods] Twenty-four time-pregnant SD rats were divided into three groups on the 6th day of gestation. Alcohol group (n = 6) received 35 calories of liquid alcohol diet every day; Control group (n = 6) was fed a liquid diet in which milk replaced alcohol isocalorically; Surrogate group (n = 12) intook food normally. Blood samples were obtained by cardiac puncture, under anesthesia, from alcohol and control groups within 6 hours after its last pup was born. The plasma concentrations of alcohol and thyroxine were determined at the Department of Clinical Laboratory, and were compared using the Kruskal - Wallis test. Pups of alcohol and control groups were fostered by surrogate mothers and executed at anesthesia at postnatal 0, 7, 14, 21 and 28 days for measuring the distribution and form of BDNF- and TrkB-immunoreactive Purkinje cells via im-munohistochemistry in the cerebellar cortex. [Results] (Dthe blood alcohol concentration was higher in alcohol group dams than in control group, with significant difference (P < 0.05) ; Thyroxine concentration was significantly decrease in alcohol group dams than in control group (P< 0.05). ?A similar developmental pattern of BDNF- and TrkB-immunoreactive Purkinje cell was observed on and after P14 in control pair-fed. These Purkinje cells of alcohol-fed group showed immature features. Single-layer arrangement of these Purkinje cells in alcohol-fed group was not completely achieved throughout postnatal life. In addition, the number of these Purkinje cell decreased at P28 as compared to control pair-fed group. [Conclusion] When dams . Exposure with alcohol within gestation, not only the blood thyroxine concentration was significantly decreased in dams, but also BDNF- and TrkB- synthesis of cerebellar cortex and growth of BDNF- and TrkB- immunoreactive Purkinje cells were impaired in offsprings.%[目的]研究出

  17. Role of the Ink4a/Arf tumor suppressors in cerebellar development, stem cells and cancer

    NARCIS (Netherlands)

    Valk-Lingbeek, Merel Esmée

    2005-01-01

    In order to take proper cell fate decisions, cells have to guide their biochemical machinery through the appropriate decisions in both differentiation and proliferation. Especially for stem cells such decisions are critical as they have the capacity to self-renew, i.e. give rise to new daughter stem

  18. Falls in degenerative cerebellar ataxias

    NARCIS (Netherlands)

    van de Warrenburg, Bart P C; Steijns, Janneke A G; Munneke, Marten; Kremer, Berry P H; Bloem, Bastiaan R

    2005-01-01

    We retrospectively and prospectively assessed the frequency and characteristics of falls in patients with degenerative cerebellar ataxias. The results show that falls occur very frequently in patients with degenerative cerebellar ataxias and that these falls are serious and often lead to injuries or

  19. In vitro study of uptake and synthesis of creatine and its precursors by cerebellar granule cells and astrocytes suggests some hypotheses on the physiopathology of the inherited disorders of creatine metabolism

    Directory of Open Access Journals (Sweden)

    Carducci Claudia

    2012-04-01

    Full Text Available Abstract Background The discovery of the inherited disorders of creatine (Cr synthesis and transport in the last few years disclosed the importance of blood Cr supply for the normal functioning of the brain. These putatively rare diseases share a common pathogenetic mechanism (the depletion of brain Cr and similar phenotypes characterized by mental retardation, language disturbances, seizures and movement disorders. In the effort to improve our knowledge on the mechanisms regulating Cr pool inside the nervous tissue, Cr transport and synthesis and related gene transcripts were explored in primary cultures of rat cerebellar granule cells and astrocytes. Methods Cr uptake and synthesis were explored in vitro by incubating monotypic primary cultures of rat type I astrocytes and cerebellar granule cells with: a D3-Creatine (D3Cr and D3Cr plus β-guanidinopropionate (GPA, an inhibitor of Cr transporter, and b labelled precursors of Guanidinoacetate (GAA and Cr (Arginine, Arg; Glycine, Gly. Intracellular D3Cr and labelled GAA and Cr were assessed by ESI-MS/MS. Creatine transporter (CT1, L-arginine:glycine amidinotransferase (AGAT, and S-adenosylmethionine:guanidinoacetate N-methyltransferase (GAMT gene expression was assessed in the same cells by real time PCR. Results D3Cr signal was extremely high in cells incubated with this isotope (labelled/unlabelled Cr ratio reached about 10 and 122, respectively in cerebellar granule cells and astrocytes and was reduced by GPA. Labelled Arg and Gly were taken up by the cells and incorporated in GAA, whose concentration paralleled that of these precursors both in the extracellular medium and inside the cells (astrocytes. In contrast, the increase of labelled Cr was relatively much more limited since labelled Cr after precursors' supplementation did not exceed 2,7% (cerebellar granule cells and 21% (astrocytes of unlabelled Cr. Finally, AGAT, GAMT and SLC6A8 were expressed in both kind of cells. Conclusions Our

  20. Spinocerebellar ataxia type 6 protein aggregates cause deficits in motor learning and cerebellar plasticity.

    Science.gov (United States)

    Mark, Melanie D; Krause, Martin; Boele, Henk-Jan; Kruse, Wolfgang; Pollok, Stefan; Kuner, Thomas; Dalkara, Deniz; Koekkoek, Sebastiaan; De Zeeuw, Chris I; Herlitze, Stefan

    2015-06-10

    Spinocerebellar ataxia type 6 (SCA6) is linked to poly-glutamine (polyQ) within the C terminus (CT) of the pore-forming subunits of P/Q-type Ca(2+) channels (Cav2.1) and is characterized by CT protein aggregates found in cerebellar Purkinje cells (PCs). One hypothesis regarding SCA6 disease is that a CT fragment of the Cav2.1 channel, which is detected specifically in cytosolic and nuclear fractions in SCA6 patients, is associated with the SCA6 pathogenesis. To test this hypothesis, we expressed P/Q-type channel protein fragments from two different human CT splice variants, as predicted from SCA6 patients, in PCs of mice using viral and transgenic approaches. These splice variants represent a short (CT-short without polyQs) and a long (CT-long with 27 polyQs) CT fragment. Our results show that the different splice variants of the CTs differentially distribute within PCs, i.e., the short CTs reveal predominantly nuclear inclusions, whereas the long CTs prominently reveal both nuclear and cytoplasmic aggregates. Postnatal expression of CTs in PCs in mice reveals that only CT-long causes SCA6-like symptoms, i.e., deficits in eyeblink conditioning (EBC), ataxia, and PC degeneration. The physiological phenotypes associated specifically with the long CT fragment can be explained by an impairment of LTD and LTP at the parallel fiber-to-PC synapse and alteration in spontaneous PC activity. Thus, our results suggest that the polyQ carrying the CT fragment of the P/Q-type channel is sufficient to cause SCA6 pathogenesis in mice and identifies EBC as a new diagnostic strategy to evaluate Ca(2+) channel-mediated human diseases.

  1. Multiplicative gain modulation arising from inhibitory synaptic plasticity in the cerebellar nuclei

    Directory of Open Access Journals (Sweden)

    Dimitris Bampasakis

    2014-03-01

    Full Text Available Neurons use the rate of action potentials to encode sensory variables. This makes the output rate as a function of input, also known as input-output (I–O relationship, a core computational function in neuronal processing. The introduction, or increase, of a modulatory input, can transform this function in multiple ways: additive transformations result in a shift, and multiplicative transformations in a change of slope of the I–O relationship. This slope change is known as gain modulation, and it can implement important forms of neural computation such as coordinate transformations. Gain modulation can be found in a wide range of brain systems, including the cerebellum, where it can be enabled by synaptic plasticity at both excitatory and inhibitory synapses. We use a realistic, conductance based, multi-compartmental model of a cerebellar nucleus (CN neuron, to investigate the determinants of gain modulation mediated by synaptic plasticity. In particular, we are interested in the effect of short term depression (STD at the inhibitory synapse from Purkinje cells (PCs to CN neurons. Considering the inhibitory PC input as the driving input, we compare the I–O relationship of the CN neuron in the presence and absence of STD for 20 Hz of excitatory synaptic input from mossy fibers (MFs, and find that STD introduces a gain change, changing the slope of the I–O function. We then proceed to compare the transformation performed by the increase of the modulatory input from 20 to 50 Hz, in the presence and absence of STD. We find that the presence of STD in the inhibitory synapse introduces a multiplicative component in the transformation performed by the excitatory input, an effect that persists for different levels of STD, and various combinations of regularity and synchronicity in the input.

  2. BK and Kv3.1 potassium channels control different aspects of deep cerebellar nuclear neurons action potentials and spiking activity.

    Science.gov (United States)

    Pedroarena, Christine M

    2011-12-01

    Deep cerebellar nuclear neurons (DCNs) display characteristic electrical properties, including spontaneous spiking and the ability to discharge narrow spikes at high frequency. These properties are thought to be relevant to processing inhibitory Purkinje cell input and transferring well-timed signals to cerebellar targets. Yet, the underlying ionic mechanisms are not completely understood. BK and Kv3.1 potassium channels subserve similar functions in spike repolarization and fast firing in many neurons and are both highly expressed in DCNs. Here, their role in the abovementioned spiking characteristics was addressed using whole-cell recordings of large and small putative-glutamatergic DCNs. Selective BK channel block depolarized DCNs of both groups and increased spontaneous firing rate but scarcely affected evoked activity. After adjusting the membrane potential to control levels, the spike waveforms under BK channel block were indistinguishable from control ones, indicating no significant BK channel involvement in spike repolarization. The increased firing rate suggests that lack of DCN-BK channels may have contributed to the ataxic phenotype previously found in BK channel-deficient mice. On the other hand, block of Kv3.1 channels with low doses of 4-aminopyridine (20 μM) hindered spike repolarization and severely depressed evoked fast firing. Therefore, I propose that despite similar characteristics of BK and Kv3.1 channels, they play different roles in DCNs: BK channels control almost exclusively spontaneous firing rate, whereas DCN-Kv3.1 channels dominate the spike repolarization and enable fast firing. Interestingly, after Kv3.1 channel block, BK channels gained a role in spike repolarization, demonstrating how the different function of each of the two channels is determined in part by their co-expression and interplay.

  3. Microglia-derived proinflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta induce Purkinje neuronal apoptosis via their receptors in hypoxic neonatal rat brain.

    Science.gov (United States)

    Kaur, Charanjit; Sivakumar, Viswanathan; Zou, Zhirong; Ling, Eng-Ang

    2014-01-01

    The developing cerebellum is extremely vulnerable to hypoxia which can damage the Purkinje neurons. We hypothesized that this might be mediated by tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) derived from activated microglia as in other brain areas. One-day-old rats were subjected to hypoxia following, which the expression changes of various proteins in the cerebellum including hypoxia inducible factor-1α, TNF-α, IL-1β, TNF-R1 and IL-1R1 were analyzed. Following hypoxic exposure, TNF-α and IL-1β immunoexpression in microglia was enhanced coupled by that of TNF-R1 and IL-1R1 in the Purkinje neurons. Along with this, hypoxic microglia in vitro showed enhanced release of TNF-α and IL-1β whose receptor expression was concomitantly increased in the Purkinje neurons. In addition, nitric oxide (NO) level was significantly increased in the cerebellum and cultured microglia subjected to hypoxic exposure. Moreover, cultured Purkinje neurons treated with conditioned medium derived from hypoxic microglia underwent apoptosis but the incidence was significantly reduced when the cells were treated with the same medium that was neutralized with TNF-α/IL-1β antibody. We conclude that hypoxic microglia in the neonatal cerebellum produce increased amounts of NO, TNF-α and IL-1β which when acting via their respective receptors could induce Purkinje neuron death.

  4. Increased excitability and altered action potential waveform in cerebellar granule neurons of the Ts65Dn mouse model of Down syndrome.

    Science.gov (United States)

    Usowicz, Maria M; Garden, Claire L P

    2012-07-17

    Down syndrome (DS) is characterized by intellectual disability and impaired motor control. Lack of coordinated movement, poor balance, and unclear speech imply dysfunction of the cerebellum, which is known to be reduced in volume in DS. The principal cause of the smaller cerebellum is a diminished number of granule cells (GCs). These neurons form the 'input layer' of the cerebellar cortex, where sensorimotor information carried by incoming mossy fibers is transformed before it is conveyed to Purkinje cells and inhibitory interneurons. However, it is not known how processing of this information is affected in the hypogranular cerebellum that characterizes DS. Here we explore the possibility that the electrical properties of the surviving GCs are changed. We find that in the Ts65Dn mouse model of DS, GCs have a higher input resistance at voltages approaching the threshold for firing, which causes them to be more excitable. In addition, they fire narrower and larger amplitude action potentials. These subtly modified electrical properties may result in atypical transfer of information at the input layer of the cerebellum.

  5. Sleep disorders in cerebellar ataxias

    Directory of Open Access Journals (Sweden)

    José L. Pedroso

    2011-04-01

    Full Text Available Cerebellar ataxias comprise a wide range of etiologies leading to central nervous system-related motor and non-motor symptoms. Recently, a large body of evidence has demonstrated a high frequency of non-motor manifestations in cerebellar ataxias, specially in autosomal dominant spinocerebellar ataxias (SCA. Among these non-motor dysfunctions, sleep disorders have been recognized, although still under or even misdiagnosed. In this review, we highlight the main sleep disorders related to cerebellar ataxias focusing on REM sleep behavior disorder (RBD, restless legs syndrome (RLS, periodic limb movement in sleep (PLMS, excessive daytime sleepiness (EDS, insomnia and sleep apnea.

  6. Interactive effects involving different classes of excitatory amino acid receptors and the survival of cerebellar granule cells in culture

    DEFF Research Database (Denmark)

    Balázs, R; Hack, N; Jørgensen, Ole Steen

    1990-01-01

    Differentiating granule cells develop survival requirements in culture which can be met by treatment with high K+ or N-methyl-D-aspartate (NMDA) and, according to our recent findings, also with low concentrations of kainic acid (KA, 50 microM). We have now attempted to elucidate the mechanism(s) ...

  7. How the Purkinje System Determines the Ventricular Activation Sequence

    Science.gov (United States)

    2007-11-02

    Zipes, Purkinje- muscle coupling and endocardial response to hyperkalemia , hypoxia, and acidosis Am.J.Physiol., vol. 247, pp. H303-H3111984. [12...R.D. Veenstra, R.W. Joyner, R.T. Wiedmann, M.L. Young, and R.C. Tan, Effects of hypoxia, hyperkalemia , and metabolic acidosis on canine subendocardial

  8. Non-cerebellar primitive neuroectodermal tumors (PNET): summary of the Milan consensus and state of the art workshop on marrow ablative chemotherapy with hematopoietic cell rescue for malignant brain tumors of childhood and adolescents.

    Science.gov (United States)

    Fangusaro, Jason; Massimino, Maura; Rutkowski, Stefan; Gururangan, Sridharan

    2010-04-01

    CNS non-cerebellar primitive neuroectodermal tumors (PNET) represent <5% of all childhood brain tumors. Despite similar therapies, these patients have had significantly worse outcomes compared to patients with medulloblastoma. Although these tumors have historically been considered analogous to medulloblastoma, there is growing evidence that they are biologically distinct. Since these tumors are relatively rare, there are few large series in the literature. Here we present the international experience treating these patients with a variety of therapies, including marrow ablative chemotherapy followed by autologous hematopoietic cell rescue.

  9. Complex partial seizures: cerebellar metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Theodore, W.H.; Fishbein, D.; Deitz, M.; Baldwin, P.

    1987-07-01

    We used positron emission tomography (PET) with (/sup 18/F)2-deoxyglucose to study cerebellar glucose metabolism (LCMRglu) and the effect of phenytoin (PHT) in 42 patients with complex partial seizures (CPS), and 12 normal controls. Mean +/- SD patient LCMRglu was 6.9 +/- 1.8 mg glucose/100 g/min (left = right), significantly lower than control values of 8.5 +/- 1.8 (left, p less than 0.006), and 8.3 +/- 1.6 (right, p less than 0.02). Only four patients had cerebellar atrophy on CT/MRI; cerebellar LCMRglu in these was 5.5 +/- 1.5 (p = 0.054 vs. total patient sample). Patients with unilateral temporal hypometabolism or EEG foci did not have lateralized cerebellar hypometabolism. Patients receiving phenytoin (PHT) at the time of scan and patients with less than 5 years total PHT exposure had lower LCMRglu, but the differences were not significant. There were weak inverse correlations between PHT level and cerebellar LCMRglu in patients receiving PHT (r = -0.36; 0.05 less than p less than 0.1), as well as between length of illness and LCMRglu (r = -0.22; 0.05 less than p less than 0.1). Patients with complex partial seizures have cerebellar hypometabolism that is bilateral and due only in part to the effect of PHT.

  10. CD4 and CD8 T cells mediate distinct lethal meningoencephalitis in mice challenged with Tacaribe arenavirus

    Science.gov (United States)

    Ireland, Derek DC; Tami, Cecilia; Pedras-Vasconcelos, Joao; Verthelyi, Daniela

    2017-01-01

    Neonates are at increased risk of viral encephalopathies that can result in neurological dysfunction, seizures, permanent disability and even death. The neurological damage results from the combined effect of the virus and the immune response it elicits, thus finding tools to facilitate viral clearance from central nervous system (CNS) while minimizing neuron damage remains a critical challenge. Neonatal mice inoculated intraperitoneally with Tacaribe virus (TCRV) develop seizures, hindlimb paralysis and death within 15 days of inoculation. TCRV localizes to the CNS within days of challenge, primarily infecting astrocytes in the cerebellum and brain stem. We show that infection leads to inflammation, T cell and monocyte infiltration into the cerebellar parenchyma, apoptosis of astrocytes, neuronal degeneration and loss of Purkinje cells. Infiltrating antigen-specific T cells fail to clear the virus but drive the disease, as T-cell-deficient CD3ɛ KO mice survive TCRV infection with minimal inflammation or clinical manifestations despite no difference in CNS viral loads in comparison with T-cell sufficient mice. CD8+ T cells drive the pathology, which even in the absence of CD4+ T-cell help, infiltrate the parenchyma and mediate the apoptotic loss of cerebellar astrocytes, neurodegeneration and loss of Purkinje cells resulting in loss of balance, paralysis and death. CD4+ T cells are also pathogenic inducing gliosis and inflammation in the cerebellum and cerebrum that are associated with wasting and death several weeks after CD4+ T-cell transfer. These data demonstrate distinct pathogenic effects of CD4+ and CD8+ T cells and identify them as possible therapeutic targets. PMID:27569560

  11. Cognition and Emotion in Cerebellar Disorders

    Science.gov (United States)

    ... cerebral cortical “association” areas important for thought, reasoning, motivation, memory and feelings. Damage to the non-motor ... tolerance. Psychosocial interaction may be impaired, particularly in children with cerebellar damage. Dementia is uncommon in cerebellar ...

  12. Precise localization of the voltage-gated potassium channel subunits Kv3.1b and Kv3.3 revealed in the molecular layer of the rat cerebellar cortex by a pre-embedding immunogold method.

    Science.gov (United States)

    Puente, Nagore; Mendizabal-Zubiaga, Juan; Elezgarai, Izaskun; Reguero, Leire; Buceta, Ianire; Grandes, Pedro

    2010-10-01

    A proper motor activity relies on a correct cerebellar function. The Kv3.1 and Kv3.3 voltage-gated potassium channels are key proteins involved in cerebellar function and dysfunction, as the lack of these causes severe motor deficits. Both channel subunits are coexpressed in granule cells and are rapidly activated at relatively positive potentials to support the generation of fast action potentials. However, the contribution of each subunit to the molecular architecture of the parallel fibers, the granule cell axons, is so far unknown. The goal of this study was to elucidate the relative distribution of Kv3.1b and Kv3.3 in specific compartments of the rat parallel fibers by using a pre-embedding immunocytochemical method for electron microscopy. Numerous Kv3.1b and Kv3.3 silver-intensified gold particles were associated with membranes of parallel fiber synaptic terminals and their intervaricose segments. Kv3.1b was found in about 85% of parallel fiber synaptic terminals and in about 47% of their intervaricose portions. However, only 28% of intervaricosities and 23% of parallel fiber presynaptic boutons were Kv3.3 immunopositive. The analysis also revealed that 54% of Purkinje cell dendritic spines localized Kv3.3. Although both potassium channel subunits share localization in the same presynaptic parallel fiber compartments, the present results with the method used indicate that there are a higher percentage of parallel fibers labeled for Kv3.1b than for Kv3.3, and that the labeling intensity for each subunit is higher in specific subcompartments analyzed than in others.

  13. Cerebellar ependymal cyst in a dog.

    Science.gov (United States)

    Wyss-Fluehmann, G; Konar, M; Jaggy, A; Vandevelde, M; Oevermann, A

    2008-11-01

    An 11-week-old, male, Staffordshire Bull Terrier had a history of generalized ataxia and falling since birth. The neurologic findings suggested a localization in the cerebellum. Magnetic resonance imaging of the brain was performed. In all sequences the area of the cerebellum was almost replaced by fluid isointense to cerebrospinal fluid. A complete necropsy was performed after euthanasia. Histologically, the lesion was characterized by extensive loss of cerebellar tissue in both hemispheres and vermis. Toward the surface of the cerebellar defect, the cavity was confined by ruptured and folded membranes consisting of a layer of glial fibrillary acidic (GFAP)-positive glial cells covered multifocally by epithelial cells. Some of these cells bore apical cilia and were cytokeratin and GFAP negative, supporting their ependymal origin. The histopathologic features of our case are consistent with the diagnosis of an ependymal cyst. Its glial and ependymal nature as demonstrated by histopathologic and immunohistochemical examination differs from arachnoid cysts, which have also been reported in dogs. The origin of these cysts remains controversial, but it has been suggested that they develop during embryogenesis subsequent to sequestration of developing neuroectoderm. We speculate that the cyst could have been the result of a pre- or perinatal, possibly traumatic, insult because hemorrhage, and tissue destruction had occurred. To our knowledge, this is the first description of an ependymal cyst in the veterinary literature.

  14. Posturography of ataxia induced by Coriolis- and Purkinje-effects.

    Science.gov (United States)

    Fitger, C; Brandt, T

    1982-02-01

    Vestibular Coriolis- and Purkinje-effect, which are known to induce vertigo, were investigated with respect to body posture. One aim of this investigation was to provide information concerning clinical vertigo symptoms. Standing on a rotatable stabilometer, 25 healthy subjects had to execute lateral head tilts during (Coriolis), or after (Purkinje), rotation varied with different constant velocities. The conditions were varied with respect to eyes open vs. eyes closed, head upright vs. head tilt to the right and left, direction of rotation clockwise vs. counterclockwise, active vs. passive head tilt, and active vs. passive body rotation. The results supported the expectation that destabilization was less severe with open than with closed eyes and that sway amplitudes were increased after head tilt as well as with a higher velocity of rotation. The direction of the induced body shift was, as expected, opposite to the initial vestibular stimulus. A forward shift after stop without head tilt was frequently found, being independent of the previous direction of rotation. Reported perceptions coincided mostly not with the initial vestibular signal but rather with the actual movement of compensation. Active instead of passive movements did not produce clearly different effects. The Purkinje experiment appeared to be equivalent to the situation when a patient with an acute lesion of a horizontal vestibular canal bends his head. The stabilogram under this condition may allow a prediction of the side of the lesion.

  15. Prenatal hypoxic-ischemic insult changes the distribution and number of NADPH-diaphorase cells in the cerebellum.

    Directory of Open Access Journals (Sweden)

    Tiago Savignon

    Full Text Available Astrogliosis, oligodendroglial death and motor deficits have been observed in the offspring of female rats that had their uterine arteries clamped at the 18(th gestational day. Since nitric oxide has important roles in several inflammatory and developmental events, here we evaluated NADPH-diaphorase (NADPH-d distribution in the cerebellum of rats submitted to this hypoxia-ischemia (HI model. At postnatal (P day 9, Purkinje cells of SHAM and non-manipulated (NM animals showed NADPH-d+ labeling both in the cell body and dendritic arborization in folia 1 to 8, while HI animals presented a weaker labeling in both cellular structures. NADPH-d+ labeling in the molecular (ML, and in both the external and internal granular layer, was unaffected by HI at this age. At P23, labeling in Purkinje cells was absent in all three groups. Ectopic NADPH-d+ cells in the ML of folia 1 to 4 and folium 10 were present exclusively in HI animals. This labeling pattern was maintained up to P90 in folium 10. In the cerebellar white matter (WM, at P9 and P23, microglial (ED1+ NADPH-d+ cells, were observed in all groups. At P23, only HI animals presented NADPH-d labeling in the cell body and processes of reactive astrocytes (GFAP+. At P9 and P23, the number of NADPH-d+ cells in the WM was higher in HI animals than in SHAM and NM ones. At P45 and at P90 no NADPH-d+ cells were observed in the WM of the three groups. Our results indicate that HI insults lead to long-lasting alterations in nitric oxide synthase expression in the cerebellum. Such alterations in cerebellar differentiation might explain, at least in part, the motor deficits that are commonly observed in this model.

  16. Defects in the CAPN1 Gene Result in Alterations in Cerebellar Development and Cerebellar Ataxia in Mice and Humans

    Directory of Open Access Journals (Sweden)

    Yubin Wang

    2016-06-01

    Full Text Available A CAPN1 missense mutation in Parson Russell Terrier dogs is associated with spinocerebellar ataxia. We now report that homozygous or heterozygous CAPN1-null mutations in humans result in cerebellar ataxia and limb spasticity in four independent pedigrees. Calpain-1 knockout (KO mice also exhibit a mild form of ataxia due to abnormal cerebellar development, including enhanced neuronal apoptosis, decreased number of cerebellar granule cells, and altered synaptic transmission. Enhanced apoptosis is due to absence of calpain-1-mediated cleavage of PH domain and leucine-rich repeat protein phosphatase 1 (PHLPP1, which results in inhibition of the Akt pro-survival pathway in developing granule cells. Injection of neonatal mice with the indirect Akt activator, bisperoxovanadium, or crossing calpain-1 KO mice with PHLPP1 KO mice prevented increased postnatal cerebellar granule cell apoptosis and restored granule cell density and motor coordination in adult mice. Thus, mutations in CAPN1 are an additional cause of ataxia in mammals, including humans.

  17. Language Impairment in Cerebellar Ataxia

    NARCIS (Netherlands)

    van Gaalen, Judith; de Swart, Bert J. M.; Oostveen, Judith; Knuijt, Simone; van de Warrenburg, Bart P. C.; Kremer, Berry (H. ) P. H.

    2014-01-01

    Background: Several studies have suggested that language impairment can be observed in patients with cerebellar pathology. The aim of this study was to investigate language performance in patients with spinocerebellar ataxia type 6 (SCA6). Methods: We assessed speech and language in 29 SCA6 patients

  18. Cerebellar Zones: A Personal History

    NARCIS (Netherlands)

    J. Voogd (Jan)

    2011-01-01

    textabstractCerebellar zones were there, of course, before anyone noticed them. Their history is that of young people, unhindered by preconceived ideas, who followed up their observations with available or new techniques. In the 1960s of the last century, the circumstances were fortunate because thr

  19. Cerebellar arteriovenous malformations in children

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, P.D. [Sheffield Univ. (United Kingdom). Acad. Dept. of Radiol.; Blaser, S.; Armstrong, D.; Chuang, S.; Harwood-Nash, D. [Division of Neuroradiology, The Hospital for Sick Children and University of Toronto, Toronto (Canada); Humphreys, R.P. [Division of Neurosurgery, The Hospital for Sick Children and University of Toronto, Toronto (Canada)

    1998-05-01

    We review the presentation, imaging findings and outcome in 18 children with cerebellar arteriovenous malformations (AVM). This group is of particular interest because of the reported poor outcome despite modern imaging and neurosurgical techniques. All children had CT and 15 underwent catheter angiography at presentation. Several of the children in the latter part of the study had MRI. Of the 18 children, 17 presented with a ruptured AVM producing intracranial haemorrhage. The remaining child presented with temporal lobe epilepsy and was shown to have temporal, vermian and cerebellar hemisphere AVM. This child had other stigmata of Osler-Weber-Rendu syndrome. Three other children had pre-existing abnormalities of possible relevance. One had a vascular malformation of the cheek and mandible, one a documented chromosomal abnormality and another a midline cleft upper lip and palate. Six of the 17 children with a ruptured cerebellar AVM died within 7 days of the ictus. Vascular pathology other than an AVM was found in 10 of the 14 children with a ruptured cerebellar AVM who had angiography: 4 intranidal aneurysms, 5 venous aneurysms and 2 cases of venous outflow obstruction (one child having both an aneurysm and obstruction). The severity of clinical presentation was directly related to the size of the acute haematoma, which was a reasonable predictor of outcome. (orig.) With 4 figs., 4 tabs., 23 refs.

  20. Effects of drotaverine hydrochloride on viability of rat cultured cerebellar granulocytes.

    Science.gov (United States)

    Demushkin, V P; Zhavoronkova, E V; Khaspekov, L G

    2012-02-01

    The neurocytotoxic effect of drotaverine hydrochloride was studied in culture of rat cerebellar granulocytes. Incubation of cells with 100 and 250 μM drotaverine reduced neuronal survival to 60 and 4%, respectively.

  1. Purinergic signaling in the cerebellum: Bergmann glial cells express functional ionotropic P2X7 receptors.

    Science.gov (United States)

    Habbas, Samia; Ango, Fabrice; Daniel, Hervé; Galante, Micaela

    2011-12-01

    Astrocytes constitute active networks of intercommunicating cells that support the metabolism and the development of neurons and affect synaptic functions via multiple pathways. ATP is one of the major neurotransmitters mediating signaling between neurons and astrocytes. Potentially acting through both purinergic metabotropic P2Y receptors (P2YRs) and ionotropic P2X receptors (P2XRs), up until now ATP has only been shown to activate P2YRs in Bergmann cells, the radial glia of the cerebellar cortex that envelopes Purkinje cell afferent synapses. In this study, using multiple experimental approaches in acute cerebellar slices we demonstrate the existence of functional P2XRs on Bergmann cells. In particular, we show here that Bergmann cells express uniquely P2X7R subtypes: (i) immunohistochemical analysis revealed the presence of P2X7Rs on Bergmann cell processes, (ii) in whole cell recordings P2XR pharmacological agonists induced depolarizing currents that were blocked by specific antagonists of P2X7Rs, and could not be elicited in slices from P2X₇R-deficient mice and finally, (iii) calcium imaging experiments revealed two distinct calcium signals triggered by application of exogenous ATP: a transient signal deriving from release of calcium from intracellular stores, and a persistent one following activation of P2X7Rs. Our data thus reveal a new pathway by which extracellular ATP may affect glial cell function, thus broadening our knowledge on purinergic signaling in the cerebellum.

  2. Diffusion and extrusion shape standing calcium gradients during ongoing parallel fiber activity in dendrites of Purkinje neurons.

    Science.gov (United States)

    Schmidt, Hartmut; Arendt, Oliver; Eilers, Jens

    2012-09-01

    Synaptically induced calcium transients in dendrites of Purkinje neurons (PNs) play a key role in the induction of plasticity in the cerebellar cortex (Ito, Physiol Rev 81:1143-1195, 2001). Long-term depression at parallel fiber-PN synapses can be induced by stimulation paradigms that are associated with long-lasting (>1 min) calcium signals. These signals remain strictly localized (Eilers et al., Learn Mem 3:159-168, 1997), an observation that was rather unexpected, given the high concentration of the mobile endogenous calcium-binding proteins parvalbumin and calbindin in PNs (Fierro and Llano, J Physiol (Lond) 496:617-625, 1996; Kosaka et al., Exp Brain Res 93:483-491, 1993). By combining two-photon calcium imaging experiments in acute slices with numerical computer simulations, we found that significant calcium diffusion out of active branches indeed takes places. It is outweighed, however, by rapid and powerful calcium extrusion along the dendritic shaft. The close interplay of diffusion and extrusion defines the spread of calcium between active and inactive dendritic branches, forming a steep gradient in calcium with drop ranges of ~13 μm (interquartile range, 10-18 μm).

  3. Cerebellar ataxia and functional genomics : Identifying the routes to cerebellar neurodegeneration

    NARCIS (Netherlands)

    Smeets, C J L M; Verbeek, D S

    2014-01-01

    Cerebellar ataxias are progressive neurodegenerative disorders characterized by atrophy of the cerebellum leading to motor dysfunction, balance problems, and limb and gait ataxia. These include among others, the dominantly inherited spinocerebellar ataxias, recessive cerebellar ataxias such as Fried

  4. Nonsurgical cerebellar mutism (anarthria) in two children.

    Science.gov (United States)

    Mewasingh, Leena D; Kadhim, Hazim; Christophe, Catherine; Christiaens, Florence J; Dan, Bernard

    2003-01-01

    Cerebellar mutism (anarthria) is a well-described complication of posterior fossa tumor resection. It is accompanied by a characteristic behavior including irritability and autistic features. This syndrome is typically reversible within days to months. Underlying pathophysiology is unknown. We describe two children who presented with a similar clinical finding after nonsurgical cerebellar involvement, hemolytic-uremic syndrome in one and cerebellitis in the other. Postmortem pathologic findings in the first patient indicated cerebellar ischemic necrosis. Single-photon emission computed tomography in the second patient revealed diffuse cerebellar hypoperfusion with no supratentorial abnormalities, refuting a phenomenon of diaschisis between cerebellar and frontal connections. These findings confirm that this clinical syndrome may occur in a nonsurgical, nontraumatic context. They are consistent with recent integrative hypotheses explaining cerebellar anarthria.

  5. Crossed cerebral - cerebellar diaschisis : MRI evaluation.

    Directory of Open Access Journals (Sweden)

    Chakravarty A

    2002-07-01

    Full Text Available MRI, done later in life, in two patients with infantile hemiplegia syndrome showed significant volume loss in the cerebellar hemisphere contralateral to the side of the affected cerebrum. The cerebellar volume loss seemed to correlate with the degree of volume loss in the contralateral cerebral hemisphere. These observations provide morphological evidence of the phenomenon of crossed cerebral-cerebellar diaschisis (CCD. Functional neuroimaging studies in support of the concept of CCD has been critically reviewed.

  6. Autosomal recessive cerebellar ataxias : the current state of affairs

    NARCIS (Netherlands)

    Vermeer, S.; van de Warrenburg, B. P. C.; Willemsen, M. A. A. P.; Cluitmans, M.; Scheffer, H.; Kremer, B. P.; Knoers, N. V. A. M.

    2011-01-01

    Among the hereditary ataxias, autosomal recessive cerebellar ataxias (ARCAs) encompass a diverse group of rare neurodegenerative disorders in which a cerebellar syndrome is the key clinical feature. The clinical overlap between the different cerebellar ataxias, the occasional atypical phenotypes, an

  7. Genetics Home Reference: VLDLR-associated cerebellar hypoplasia

    Science.gov (United States)

    ... Conditions VLDLR-associated cerebellar hypoplasia VLDLR-associated cerebellar hypoplasia Enable Javascript to view the expand/collapse boxes. ... Open All Close All Description VLDLR -associated cerebellar hypoplasia is an inherited condition that affects the development ...

  8. [Peripheral neuropathies associated with hereditary cerebellar ataxias].

    Science.gov (United States)

    Anheim, M; Tranchant, C

    2011-01-01

    Inherited cerebellar ataxias constitute a complicated and heterogeneous group of neurodegenerative disorders affecting the cerebellum and/or spinocerebellar tract, spinal cord and peripheral nerves. A peripheral neuropathy is frequently seen in inherited cerebellar ataxias although it rarely reveals the disease. Moreover, the peripheral neuropathy is helpful for the diagnostic procedure and contributes to the functional prognosis of the disease. Thus, electroneuromyography is essential in the algorithm for the diagnosis of inherited cerebellar ataxias, as well as brain MRI (looking especially for cerebellar atrophy) and the assessment of several biomarkers (alpha-foetoprotein, vitamin E, albumin, LDL cholesterol, lactic acid, phytanic acid).

  9. 神经干细胞移植治疗遗传性小脑萎缩的临床研究%Clinical study of transplantation of neural stem cells in therapy of inherited cerebellar atrophy

    Institute of Scientific and Technical Information of China (English)

    田增民; 陈涛; Nanbert ZHONG; 李志超; 尹丰; 刘爽

    2009-01-01

    Objective:To study the clinical effect of neural stem cell transplantation in the treatment of inherited cerebellar atrophy (CA). Methods: The cells from human fetal cerebellum (8-10 weeks of gestation) were grown and expanded in vitro. The cultured neurospheres were then implanted into the dentate nuclei of patients by stereo tactic operation. Totally, 12 patients (7 males and 5 females with age ranging 22-62 years, mean 43 years) were treated by this operation from August 2006 to August 2008. Results: The cells of fetal cerebellum were expanded by 107folds in undifferentiated state in the culture. After the operation, no rejection was detected. Follow up, the effective rates were 58. 3% after 3 months, 75.0% after 6 months, and 66.7% for 12-24 months (mean 18 months). Conclusion: the transplantation of in vitro cultured neural stem cell is a feasible and effective treatment for inherited CA, but the long term effectiveness need to be taken in consideration.

  10. Qualitative and quantitative aspects of the microanatomy of the African elephant cerebellar cortex.

    Science.gov (United States)

    Maseko, Busisiwe C; Jacobs, Bob; Spocter, Muhammad A; Sherwood, Chet C; Hof, Patrick R; Manger, Paul R

    2013-01-01

    The current study provides a number of novel observations on the organization and structure of the cerebellar cortex of the African elephant by using a combination of basic neuroanatomical and immunohistochemical stains with Golgi and stereologic analysis. While the majority of our observations indicate that the cerebellar cortex of the African elephant is comparable to other mammalian species, several features were unique to the elephant. The three-layered organization of the cerebellar cortex, the neuronal types and some aspects of the expression of calcium-binding proteins were common to a broad range of mammalian species. The Lugaro neurons observed in the elephant were greatly enlarged in comparison to those of other large-brained mammals, suggesting a possible alteration in the processing of neural information in the elephant cerebellar cortex. Analysis of Golgi impregnations indicated that the dendritic complexity of the different interneuron types was higher in elephants than other mammals. Expression of parvalbumin in the parallel fibers and calbindin expressed in the stellate and basket cells also suggested changes in the elephant cerebellar neuronal circuitry. The stereologic analysis confirmed and extended previous observations by demonstrating that neuronal density is low in the elephant cerebellar cortex, providing for a larger volume fraction of the neuropil. With previous results indicating that the elephants have the largest relative cerebellar size amongst mammals, and one of the absolutely largest mammalian cerebella, the current observations suggest that the elephants have a greater volume of a potentially more complexly organized cerebellar cortex compared to other mammals. This quantitatively larger and more complex cerebellar cortex likely represents part of the neural machinery required to control the complex motor patterns involved in movement of the trunk and the production of infrasonic vocalizations.

  11. 人脐带间充质干细胞移植治疗小脑萎缩%Transplantation of Human Umbilical-Cord Mesenchymal Stem Cells in Treatment of Cerebellar Atrophy

    Institute of Scientific and Technical Information of China (English)

    应奇; 王毛毛; 张风林; 徐小龙; 郭子宽; 许志方

    2013-01-01

    目的 研究人脐带间充质干细胞(Human umbilical-cord mesenchymal stem cells,hUMSCs)治疗小脑萎缩(Cerebellar atrophy,CA)的临床疗效.方法 健康新生儿脐带中分离MSCs,连续体外扩增,采用鞘内注射(2.5×1075 mL)结合静脉滴注(7.5×107100 mL)的方法,治疗57例小脑萎缩患者,每次治疗剂量为1.0× 108个细胞.结果 所有患者随访6个月,治疗3个月后有效率为72.0%,治疗6个月后有效率为79.0%,无明显并发症.结论 应用hUMSCs治疗小脑萎缩安全有效,但远期疗效尚待进一步观察.%Objective To evaluate the clinical effectiveness of transplantation of human umbilical-cord mesenchymal stem cells (hUMSCs) in the treatment of cerebellar atrophy (CA). Methods The mesenchymal stem cells (MSCs) were separated from umbilical -cord of healthy newborn and were cultured to a large amount in vitro. Then hUMSCs were transplanted (cell amount: 1.0×108) into CA patients (57 cases) by intra-dural injection (2.5×107/5 mL) and intravenous injection (7.5×107/100 mL). Results All the patients were followed up for 6 months. The effective rate were 72.0% 3 months after transplantation and 79.0% 6 months after transplantation respectively. No complication were observed. Conclusion hUMSCs treating CA is safe and effective, but its long-term effectiveness should be further observed.

  12. Electrophysiological effects of haloperidol on isolated rabbit Purkinje fibers and guinea pigs papillary muscles under normal and simulated ischemia

    Institute of Scientific and Technical Information of China (English)

    Dong YAN; Lu-feng CHENG; Hong-yan SONG; Subat TURDI; Parhat KERRAM

    2007-01-01

    Aim: Overdoses of haloperidol are associated with major ventricular arrhythmias,cardiac conduction block, and sudden death. The aim of this experiment was to study the effect of haloperidol on the action potentials in cardiac Purkinje fibers and papillary muscles under normal and simulated ischemia conditions in rabbits and guinea pigs. Methods: Using the standard intracellular microelectrode technique, we examined the effects of haloperidol on the action potential param-eters [action potential amplitude (APA), phase 0 maximum upstroke velocity (Vmax),action potential amplitude at 90% of repolarization (APD90), and effective refrac-tory period (ERP)] in rabbit cardiac Purkinje fibers and guinea pig cardiac papillary cells, in which both tissues were under simulated ischemic conditions. Results: Under ischemic conditions, different concentrations of haloperidol depressed APA and prolonged APD90 in a concentration-dependent manner in rabbit Purkinje fibers. Haloperidol (3 μmol/L) significantly depressed APA and prolonged APD90,and from 1 μmol/L, haloperidol showed significant depression on Vmax; ERP was not significantly affected. In guinea pig cardiac papillary muscles, the thresholds of significant reduction in APA, Vmax, EPR, and APD90 were 10, 0.3, 1, and 1 μmol/L, respectively, for haloperidol. Conclusion: Compared with cardiac con-ductive tissues, papillary muscles were more sensitive to ischemic conditions. Under ischemia, haloperidol prolonged ERP and APD90 in a concentration-depen-dent manner and precipitated the decrease in Vmax induced by ischemia. The shortening of ERP and APD90 in papillary muscle action potentials may be inhibi-ted by haloperidol.

  13. Functional effects of the late sodium current inhibition by AZD7009 and lidocaine in rabbit isolated atrial and ventricular tissue and Purkinje fibre.

    Science.gov (United States)

    Persson, Frida; Andersson, Birgit; Duker, Göran; Jacobson, Ingemar; Carlsson, Leif

    2007-03-08

    AZD7009 (tert-Butyl-2-(7-[(2S)-3-(4-cyanophenoxy)-2-hydroxypropyl]-9-oxa-3,7-diazabicyclo[3.3.1]non-3-yl)ethylcarbamate) is an antiarrhythmic agent that increases atrial refractoriness, shows high antiarrhythmic efficacy and has low proarrhythmic potential. This study was primarily undertaken to determine the effects of AZD7009 on the late sodium current and to examine the impact of late sodium current inhibition on action potential duration in various myocardial cells. AZD7009 inhibited the late sodium current in Chinese Hamster Ovary K1 (CHO K1) cells expressing hNa(v)1.5 with an IC(50) of 11+/-2 microM. The late sodium current in isolated rabbit atrial and ventricular myocytes was also concentration dependently inhibited by AZD7009. Action potentials were recorded during exposure to 5 microM E-4031 (1-[2-(6-methyl-2pyridyl)ethyl]-4-(4-methylsulfonyl aminobenzoyl)piperidine), a compound that selectively inhibits the rapid delayed rectifier potassium current (I(Kr)), and to E-4031 in combination with AZD7009 or lidocaine in rabbit atrial and ventricular tissue and Purkinje fibres. In Purkinje fibres, but not in ventricular tissue, AZD7009 and lidocaine attenuated the E-4031-induced action potential duration prolongation. In atrial cells, AZD7009, but not lidocaine, further prolonged the E-4031-induced action potential duration. E-4031 induced early afterdepolarisations (EADs) in Purkinje fibres, EADs that were totally suppressed by AZD7009 or lidocaine. In conclusion, excessive action potential duration prolongation induced by E-4031 was attenuated by AZD7009 and lidocaine in rabbit Purkinje fibre, but not in atrial or ventricular tissue, most likely by inhibiting the late sodium current. Furthermore, the opposite effect by AZD7009 on action potential duration in atrial tissue suggests that AZD7009, in addition to inhibiting I(Kr), also inhibits other repolarising currents in the atria.

  14. The clinical presentation of preterm cerebellar haemorrhage

    NARCIS (Netherlands)

    G.M. Ecury-Goossen (Ginette); J. Dudink (Jeroen); M. Leguin (Maarten); M. Feijen-Roon (Monique); S. Horsch (Sandra); P. Govaert (Paul)

    2010-01-01

    textabstractThe objective of this study was to evaluate clinical symptoms and findings on cranial ultrasound (CUS) in preterm infants with cerebellar haemorrhage through retrospective analysis of all preterm infants with a postnatal CUS or MRI diagnosis of cerebellar haemorrhage admitted in a tertia

  15. Endoplasmic reticulum membrane-sorting protein of lymphocytes (BAP31) is highly expressed in neurons and discrete endocrine cells.

    Science.gov (United States)

    Manley, H A; Lennon, V A

    2001-10-01

    BAP31 is a transmembrane protein that associates with nascent membrane proteins in transit between endoplasmic reticulum (ER) and cis-Golgi. Its C-terminal dilysine (KKEE) motif, mediating return to the ER, is consistent with a role in early sorting of membrane proteins. An initiator caspase-binding site in the C-terminal domain of BAP31 is implicated in cytoplasmic membrane fragmentation events of apoptosis. Although BAP31 RNA is ubiquitous, the protein's anatomic localization has not been determined. To gain further insight into its possible functions, we localized BAP31 in primate tissues using monoclonal antibodies. Immunoreactivity was prominent in T- and B-lymphocytes in blood and in thymus, in cerebellar Purkinje neuron bodies and dendrites, in gonadotrophs of the anterior pituitary, ovarian thecal and follicular cells, active but not quiescent thyroid epithelium, adrenal cortex more than medulla, and proximal more than distal renal tubules. Blood vessels and skeletal muscle were nonreactive. The anatomic distribution of BAP31 and the nature of proteins identified thus far as its cargo exiting the ER, suggest an interaction with proteins assembling in macromolecular complexes en route to selected sites of exocytotic and signaling activities. Apoptotic associations in mature tissues could be physiological (lymphocytes, endocrine cells) or pathological (Purkinje neurons, renal tubules).

  16. Cellular and Molecular Basis of Cerebellar Development

    Directory of Open Access Journals (Sweden)

    Salvador eMartinez

    2013-06-01

    Full Text Available Historically, the molecular and cellular mechanisms of cerebellar development were investigated through structural descriptions and studying spontaneous mutations in animal models and humans. Advances in experimental embryology, genetic engineering and neuroimaging techniques render today the possibility to approach the analysis of molecular mechanisms underlying histogenesis and morphogenesis of the cerebellum by experimental designs. Several genes and molecules were identified to be involved in the cerebellar plate regionalization, specification and differentiation of cerebellar neurons, as well as the establishment of cellular migratory routes and the subsequent neuronal connectivity. Indeed, pattern formation of the cerebellum requires the adequate orchestration of both key morphogenetic signals, arising from distinct brain regions, and local expression of specific transcription factors. Thus, the present review wants to revisit and discuss these morphogenetic and molecular mechanisms taking place during cerebellar development in order to understand causal processes regulating cerebellar cytoarchitecture, its highly topographically ordered circuitry and its role in brain function.

  17. Cerebellar stroke-manifesting as mania

    Directory of Open Access Journals (Sweden)

    Venkatesan Jagadesan

    2014-01-01

    Full Text Available Secondary mania resulting from cerebral Cortex are described commonly. But secondary mania produced by cerebellar lesions are relatively uncommon. This case report describes a patient who developed cerebellar stoke and manic features simultaneously. 28 years old male developed giddiness and projectile vomiting. Then he would lie down for about an hour only to find that he could not walk. He became quarrelsome. His Psycho motor activities and speech were increased. He was euphoric and was expressing grandiose ideas. Bender Gestalt Test showed signs of organicity. Score in Young mania relating scale was 32; productivity was low in Rorschach. Neurological examination revealed left cerebellar signs like ataxia and slurring of speech. Computed tomography of brain showed left cerebellar infarct. Relationship between Psychiatric manifestations and cerebellar lesion are discussed.

  18. The bihemispheric posterior inferior cerebellar artery

    Energy Technology Data Exchange (ETDEWEB)

    Cullen, Sean P. [Brigham and Women' s Hospital and Children' s Hospital, Department of Radiology and Neurosurgery, Boston, MA (United States); Ozanne, Augustin; Alvarez, Hortensia; Lasjaunias, Pierre [Service de Neuroradiologie Diagnostic et Therapeutique, Hopital de Bicetre-Universite Paris-sud Orsay (France)

    2005-11-01

    Rarely, a solitary posterior inferior cerebellar artery (PICA) will supply both cerebellar hemispheres. We report four cases of this variant. We present a retrospective review of clinical information and imaging of patients undergoing angiography at our institution to identify patients with a bihemispheric PICA. There were four patients: three males and one female. One patient presented with a ruptured arteriovenous malformation, and one with a ruptured aneurysm. Two patients had normal angiograms. The bihemispheric PICA was an incidental finding in all cases. The bihemispheric vessel arose from the dominant left vertebral artery, and the contralateral posterior inferior cerebellar artery was absent or hypoplastic. In all cases, contralateral cerebellar supply arose from a continuation of the ipsilateral PICA distal to the choroidal point and which crossed the midline dorsal to the vermis. We conclude that the PICA may supply both cerebellar hemispheres. This rare anatomic variant should be considered when evaluating patients with posterior fossa neurovascular disease. (orig.)

  19. Altered cerebellar feedback projections in Asperger syndrome.

    Science.gov (United States)

    Catani, Marco; Jones, Derek K; Daly, Eileen; Embiricos, Nitzia; Deeley, Quinton; Pugliese, Luca; Curran, Sarah; Robertson, Dene; Murphy, Declan G M

    2008-07-15

    It has been proposed that the biological basis of autism spectrum disorder includes cerebellar 'disconnection'. However, direct in vivo evidence in support of this is lacking. Here, the microstructural integrity of cerebellar white matter in adults with Asperger syndrome was studied using diffusion tensor magnetic resonance tractography. Fifteen adults with Asperger syndrome and 16 age-IQ-gender-matched healthy controls underwent diffusion tensor magnetic resonance imaging. For each subject, tract-specific measurements of mean diffusivity and fractional anisotropy were made within the inferior, middle, superior cerebellar peduncles and short intracerebellar fibres. No group differences were observed in mean diffusivity. However, people with Asperger syndrome had significantly lower fractional anisotropy in the short intracerebellar fibres (pAsperger syndrome. The localised abnormalities in the main cerebellar outflow pathway may prevent the cerebral cortex from receiving those cerebellar feedback inputs necessary for a successful adaptive social behaviour.

  20. A model of long-term memory storage in the cerebellar cortex: a possible role for plasticity at parallel fiber synapses onto stellate/basket interneurons.

    Science.gov (United States)

    Kenyon, G T

    1997-12-09

    By evoking changes in climbing fiber activity, movement errors are thought to modify synapses from parallel fibers onto Purkinje cells (pf*Pkj) so as to improve subsequent motor performance. Theoretical arguments suggest there is an intrinsic tradeoff, however, between motor adaptation and long-term storage. Assuming a baseline rate of motor errors is always present, then repeated performance of any learned movement will generate a series of climbing fiber-mediated corrections. By reshuffling the synaptic weights responsible for any given movement, such corrections will degrade the memories for other learned movements stored in overlapping sets of synapses. The present paper shows that long-term storage can be accomplished by a second site of plasticity at synapses from parallel fibers onto stellate/basket interneurons (pf*St/Bk). Plasticity at pf*St/Bk synapses can be insulated from ongoing fluctuations in climbing fiber activity by assuming that changes in pf*St/Bk synapses occur only after changes in pf*Pkj synapses have built up to a threshold level. Although climbing fiber-dependent plasticity at pf*Pkj synapses allows for the exploration of novel motor strategies in response to changing environmental conditions, plasticity at pf*St/Bk synapses transfers successful strategies to stable long-term storage. To quantify this hypothesis, both sites of plasticity are incorporated into a dynamical model of the cerebellar cortex and its interactions with the inferior olive. When used to simulate idealized motor conditioning trials, the model predicts that plasticity develops first at pf*Pkj synapses, but with additional training is transferred to pf*St/Bk synapses for long-term storage.

  1. The role of Purkinje-myocardial coupling during ventricular arrhythmia: a modeling study.

    Directory of Open Access Journals (Sweden)

    Elham Behradfar

    Full Text Available The Purkinje system is the fast conduction network of the heart which couples to the myocardium at discrete sites called Purkinje-Myocyte Junctions (PMJs. However, the distribution and number of PMJs remains elusive, as does whether a particular PMJ is functional. We hypothesized that the Purkinje system plays a role during reentry and that the number of functional PMJs affect reentry dynamics. We used a computer finite element model of rabbit ventricles in which we varied the number of PMJs. Sustained, complex reentry was induced by applying an electric shock and the role of the Purkinje system in maintaining the arrhythmia was assessed by analyzing phase singularities, frequency of activation, and bidirectional propagation at PMJs. For larger junctional resistances, increasing PMJ density increased the mean firing rate in the Purkinje system, the percentage of successful retrograde conduction at PMJs, and the incidence of wave break on the epicardium. However, the mean firing of the ventricles was not affected. Furthermore, increasing PMJ density above 13/[Formula: see text] did not alter reentry dynamics. For lower junctional resistances, the trend was not as clear. We conclude that Purkinje system topology affects reentry dynamics and conditions which alter PMJ density can alter reentry dynamics.

  2. Cellular and Axonal Diversity in Molecular Layer Heterotopia of the Rat Cerebellar Vermis

    Directory of Open Access Journals (Sweden)

    Sarah E. Van Dine

    2013-01-01

    Full Text Available Molecular layer heterotopia of the cerebellar primary fissure are a characteristic of many rat strains and are hypothesized to result from defect of granule cells exiting the external granule cell layer during cerebellar development. However, the cellular and axonal constituents of these malformations remain poorly understood. In the present report, we use histochemistry and immunocytochemistry to identify neuronal, glial, and axonal classes in molecular layer heterotopia. In particular, we identify parvalbumin-expressing molecular layer interneurons in heterotopia as well as three glial cell types including Bergmann glia, Olig2-expressing oligodendrocytes, and Iba1-expressing microglia. In addition, we document the presence of myelinated, serotonergic, catecholaminergic, and cholinergic axons in heterotopia indicating possible spinal and brainstem afferent projections to heterotopic cells. These findings are relevant toward understanding the mechanisms of normal and abnormal cerebellar development.

  3. Cerebellar Ataxia and Glutamic Acid Decarboxylase Antibodies

    Science.gov (United States)

    Ariño, Helena; Gresa-Arribas, Nuria; Blanco, Yolanda; Martínez-Hernández, Eugenia; Sabater, Lidia; Petit-Pedrol, Mar; Rouco, Idoia; Bataller, Luis; Dalmau, Josep O.; Saiz, Albert; Graus, Francesc

    2016-01-01

    IMPORTANCE Current clinical and immunologic knowledge on cerebellar ataxia (CA) with glutamic acid decarboxylase 65 antibodies (GAD65-Abs) is based on case reports and small series with short-term follow-up data. OBJECTIVE To report the symptoms, additional antibodies, prognostic factors, and long-term outcomes in a cohort of patients with CA and GAD65-Abs. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study and laboratory investigations at a center for autoimmune neurologic disorders among 34 patients with CA and GAD65-Abs, including 25 with long-term follow-up data (median, 5.4 years; interquartile range, 3.1-10.3 years). MAIN OUTCOMES AND MEASURES Analysis of clinicoimmunologic features and predictors of response to immunotherapy. Immunochemistry on rat brain, cultured neurons, and human embryonic kidney cells expressing GAD65, GAD67, α1-subunit of the glycine receptor, and a repertoire of known cell surface autoantigens were used to identify additional antibodies. Twenty-eight patients with stiff person syndrome and GAD65-Abs served as controls. RESULTS The median age of patients was 58 years (range, 33-80 years); 28 of 34 patients (82%) were women. Nine patients (26%) reported episodes of brainstem and cerebellar dysfunction or persistent vertigo several months before developing CA. The clinical presentation was subacute during a period of weeks in 13 patients (38%). Nine patients (26%) had coexisting stiff person syndrome symptoms. Systemic organ-specific autoimmunities (type 1 diabetes mellitus and others) were present in 29 patients (85%). Twenty of 25 patients with long-term follow-up data received immunotherapy (intravenous immunoglobulin in 10 and corticosteroids and intravenous immunoglobulin or other immunosuppressors in 10), and 7 of them (35%) improved. Predictors of clinical response included subacute onset of CA (odds ratio [OR], 0.50; 95% CI, 0.25-0.99; P = .047) and prompt immunotherapy (OR, 0.98; 95% CI, 0.96-0.99; P = .01). Similar

  4. Sustained Reduction of Cerebellar Activity in Experimental Epilepsy

    Directory of Open Access Journals (Sweden)

    Kim Rijkers

    2015-01-01

    Full Text Available Clinical and experimental evidence suggests a role for the cerebellum in seizure control, while no data are available on cerebellar activity between seizures. We hypothesized that interictal regional activity of the deep cerebellar nuclei is reduced in epilepsy and tested this in an animal model by using ΔFosB and cytochrome oxidase (COX (immunohistochemistry. The expression of these two markers of neuronal activity was analysed in the dentate nucleus (DN, interpositus nucleus (IN, and fastigial nucleus (FN of the cerebellum of fully amygdala kindled rats that were sacrificed 48 hours after their last seizure. The DN and FN of kindled rats exhibited 25 to 29% less ΔFosB immunopositive cells than their respective counterpart in sham controls (P<0.05. COX expression in the DN and FN of kindled animals was reduced by 32 to 33% compared to respective control values (P<0.05. These results indicate that an epileptogenic state is characterized by decreased activity of deep cerebellar nuclei, especially the DN and FN. Possible consequences may include a decreased activation of the thalamus, contributing to further seizure spread. Restoration of FN activity by low frequency electrical stimulation is suggested as a possible treatment option in chronic epilepsy.

  5. Inpatient Rehabilitation Performance of Patients with Paraneoplastic Cerebellar Degeneration

    Science.gov (United States)

    Fu, Jack B.; Raj, Vishwa S.; Asher, Arash; Lee, Jay; Guo, Ying; Konzen, Benedict S.; Bruera, Eduardo

    2014-01-01

    Objective To evaluate the functional improvement of rehabilitation inpatients with paraneoplastic cerebellar degeneration. Design Retrospective Review Setting Three tertiary referral based hospitals. Interventions Medical records were retrospectively analyzed for demographic, laboratory, medical and functional data. Main Outcome Measure Functional Independence Measure (FIM) Participants Cancer rehabilitation inpatients admitted to three different cancer centers with a diagnosis of paraneoplastic cerebellar degeneration (n=7). Results All 7 patients were white females. Median age was 62. Primary cancers included ovarian carcinoma (2), small cell lung cancer (2), uterine carcinoma (2), and invasive ductal breast carcinoma. Mean admission total FIM score was 61.0 (SD=23.97). Mean discharge total FIM score was 73.6 (SD=29.35). The mean change in total FIM score was 12.6 (p=.0018). The mean length of rehabilitation stay was 17.1 days. The mean total FIM efficiency was 0.73. 5/7 (71%) patients were discharged home. 1/7 (14%) was discharged to a nursing home. 1/7 (14%) transferred to the primary acute care service. Conclusions This is the first study to demonstrate the functional performance of a group of rehabilitation inpatients with paraneoplastic cerebellar degeneration. Despite the poor neurologic prognosis associated with this syndrome, these patients made significant functional improvements on inpatient rehabilitation. When appropriate, inpatient rehabilitation should be considered. Further studies with larger sample sizes are needed. PMID:25051460

  6. Cerebellar Involvement in Ataxia and Generalized Epilepsy

    NARCIS (Netherlands)

    L. Kros (Lieke)

    2015-01-01

    markdownabstract__Abstract__ The work described in this thesis was performed in order to elucidate the role of different cerebellar modules in ataxia and generalized epilepsy using various techniques including in vivo electrophysiology, optogenetics, pharmacological interventions, immunohistology a

  7. Cerebellar mutism: review of the literature

    DEFF Research Database (Denmark)

    Gudrunardottir, Thora; Sehested, Astrid; Juhler, Marianne;

    2011-01-01

    Cerebellar mutism is a common complication of posterior fossa surgery in children. This article reviews current status with respect to incidence, anatomical substrate, pathophysiology, risk factors, surgical considerations, treatment options, prognosis and prevention.......Cerebellar mutism is a common complication of posterior fossa surgery in children. This article reviews current status with respect to incidence, anatomical substrate, pathophysiology, risk factors, surgical considerations, treatment options, prognosis and prevention....

  8. Nitric oxide promotes survival of cerebellar granule neurons cultured in vitro through the Akt pathway

    Institute of Scientific and Technical Information of China (English)

    Lin Wang; Mei Li; Lihua Zhou

    2011-01-01

    In this study, cerebellar granule neurons were used to examine the role of nitric oxide on cell survival. The N-methyl-D-aspartic acid receptor antagonist, MK-801, and the soluble guanylate cyclase antagonist, 1H-[1, 2, 4]oxadiazolo-[4, 3-a] quinoxalin-1-one, decreased cell viability, induced caspase-3, and decreased phosphorylated-Akt levels, suggesting that blockade of nitric oxide production promotes apoptosis of differentiating cerebellar granule neurons. After administration of sodium nitroprusside, an endogenous nitric oxide donor, cell viability recovered,caspase-3 expression was decreased, and phosphorylated-Akt levels increased. This study provides direct evidence that nitric oxide can sustain the survival of developing cerebellar granule neurons in vitro through the nitric oxide-Akt pathway. Moreover, endogenous nitric oxide exerts these effects in a cyclic guanosine monophosphate-dependent manner while exogenous nitric oxide does so in a cyclic guanosine monophosphate-independent manner.

  9. Lingo-1 expression is increased in essential tremor cerebellum and is present in the basket cell pinceau.

    Science.gov (United States)

    Kuo, Sheng-Han; Tang, Guomei; Louis, Elan D; Ma, Karen; Babji, Rachel; Balatbat, Matthew; Cortes, Etty; Vonsattel, Jean-Paul G; Yamamoto, Ai; Sulzer, David; Faust, Phyllis L

    2013-06-01

    The Lingo-1 sequence variant has been associated with essential tremor (ET) in several genome-wide association studies. However, the role that Lingo-1 might play in pathogenesis of ET is not understood. Since Lingo-1 protein is a negative regulator of axonal regeneration and neurite outgrowth, it could contribute to Purkinje cell (PC) or basket cell axonal pathology observed in postmortem studies of ET brains. In this study, we used Western blotting and immunohistochemistry to examine Lingo-1 protein in ET vs. control brains. In Western blots, Lingo-1 protein expression level was significantly increased in cerebellar cortex (1.56 ± 0.46 in ET cases vs. 0.99 ± 0.20 in controls, p = 0.002), but was similar in the occipital cortex (p = 1.00) of ET cases vs. controls. Lingo-1 immunohistochemistry in cerebellum revealed that Lingo-1 was enriched in the distal axonal processes of basket cells, which formed a "pinceau" structure around the PC axon initial segment (AIS). We found that some Lingo-1-positive pinceau had abnormally elongated processes, targeting PC axon segments distal to the AIS. In ET cases, the percentage of Lingo-1-positive pinceau that were ≥30 or ≥40 μm in length was increased 2.4- to 4.1-fold, respectively, vs. pinceau seen in control brains (p Lingo-1-positive pinceau strongly correlated with number of PC axonal torpedoes and a rating of basket cell axonal pathology. The increased cerebellar Lingo-1 expression and elongated Lingo-1-positive pinceau processes could contribute to the abnormal PC and basket cell axonal pathology and cerebellar dysfunction observed in ET.

  10. Expression of classical cadherins in the cerebellar anlage: quantitative and functional aspects.

    Science.gov (United States)

    Gliem, Michael; Weisheit, Gunnar; Mertz, Kirsten D; Endl, Elmar; Oberdick, John; Schilling, Karl

    2006-12-01

    During central nervous system (CNS) development, cell migration precedes and is key to the integration of diverse sets of cells. Mechanistically, CNS histogenesis is realized through a balanced interplay of cell-cell and cell-matrix adhesion molecules. Here, we summarize experiments that probe the developmental expression and potential significance of a set of cadherins, including M-, N- and R-cadherin, for patterning of the cerebellar cortex. We established a transgenic marker that allows cerebellar granule cells to be followed from the neuroblast stage to their final, postmitotic settlement. In conjunction with flow cytometry, this allowed us to derive a quantitative view of cadherin expression in differentiating granule cells and relate it to the expression of the same cadherins in cerebellar inhibitory interneuronal precursors. In vitro reaggregation analysis supports a role for cadherins in cell sorting and migration within the nascent cerebellar cortex that may be rationalized within the context of the differential adhesion hypothesis (Foty, R.A. and Steinberg, M.S., 2005. The differential adhesion hypothesis: a direct evaluation. Dev. Biol. 278, 255-263.).

  11. C-fos protein expression in the cerebellar dentate nuclei and Purkinje cells of the amygdala-kindled rats%杏仁核点燃癫癎鼠小脑齿状核和浦肯野细胞fos蛋白的表达

    Institute of Scientific and Technical Information of China (English)

    毛诗贤; 伍国锋; 董佑忠

    2004-01-01

    目的:探讨癫癎的病理生理机制.方法:采用免疫组化的方法,在杏仁核点燃的大鼠癫癎模型上,观察小脑齿状核和浦肯野细胞fos蛋白的表达情况.结果:在杏仁核点燃癫癎大鼠,不同发作级别其fos表达强度不同,Ⅰ~Ⅲ级发作时小脑齿状核和浦肯野细胞fos蛋白的表达为弱阳性核团,Ⅳ-Ⅴ级发作时小脑齿状核和浦肯野细胞fos蛋白的表达为强阳性核团.结论:小脑齿状核和浦肯野细胞极可能参与杏仁核点燃癫癎的病理生理过程.

  12. Bilateral Cerebellar Cortical Dysplasia without Other Malformations: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jung Seok; Ahn Kook Jin; Kim, Jee Young; Lee, Sun Jin; Park, Jeong Mi [Catholic University Yeouido St. Mary' s Hospital, College of Medicine, Seoul (Korea, Republic of)

    2010-06-15

    Recent advances in MRI have revealed congenital brain malformations and subtle developmental abnormalities of the cerebral and cerebellar cortical architecture. Typical cerebellar cortical dysplasia as a newly categorized cerebellar malformation, has been seen in patients with Fukuyama congenital muscular dystrophy. Cerebellar cortical dysplasia occurs at the embryonic stage and is often observed in healthy newborns. It is also incidentally and initially detected in adults without symptoms. To the best of our knowledge, cerebellar dysplasia without any related disorders is very rare. We describe the MRI findings in one patient with disorganized foliation of both cerebellar hemispheres without a related disorder or syndrome

  13. Imaging calcium waves in cerebellar Bergmann glia.

    Science.gov (United States)

    Beierlein, Michael

    2013-01-01

    This protocol describes methods for recording synaptically evoked Ca(2+) waves from individual Bergmann glia (BG) in slices of cerebellar cortex. Unlike protoplasmic, star-shaped astrocytes, whose thin processes pose a serious challenge to stable Ca(2+) measurements, BG are large radial cells, with several main processes that run over distances of several hundred micrometers toward the pia and ensheathe thousands of parallel fiber (PF) synapses. Stimulation of PF synapses with brief bursts can trigger long-lasting Ca(2+) responses in BG processes, which can be reliably recorded using a cooled charge-coupled device (CCD) camera. This protocol was developed to enable measurements of Ca(2+) waves in individual BG loaded with a high-affinity Ca(2+) indicator such as Fura-2 for up to 2 h. Because BG recorded in slices rarely display spontaneous (i.e., tetrodotoxin [TTX]-sensitive) or intrinsic Ca(2+) transients, Ca(2+) waves can be evoked repeatedly and reliably, which permits quantitative studies using pharmacological tools. Fluorescence measurements obtained using CCD technology offer a straightforward means of characterizing the mechanisms and potential functional consequences of widespread and long-lasting, store-mediated Ca(2+) increases in astrocytes.

  14. The chromatin remodeling factor CHD7 controls cerebellar development by regulating reelin expression

    Science.gov (United States)

    Whittaker, Danielle E.; Riegman, Kimberley L.H.; Kasah, Sahrunizam; Mohan, Conor; Yu, Tian; Sala, Blanca Pijuan; Hebaishi, Husam; Caruso, Angela; Marques, Ana Claudia; Michetti, Caterina; Smachetti, María Eugenia Sanz; Shah, Apar; Sabbioni, Mara; Kulhanci, Omer; Tee, Wee-Wei; Reinberg, Danny; Scattoni, Maria Luisa; McGonnell, Imelda; Wardle, Fiona C.; Fernandes, Cathy

    2017-01-01

    The mechanisms underlying the neurodevelopmental deficits associated with CHARGE syndrome, which include cerebellar hypoplasia, developmental delay, coordination problems, and autistic features, have not been identified. CHARGE syndrome has been associated with mutations in the gene encoding the ATP-dependent chromatin remodeler CHD7. CHD7 is expressed in neural stem and progenitor cells, but its role in neurogenesis during brain development remains unknown. Here we have shown that deletion of Chd7 from cerebellar granule cell progenitors (GCps) results in reduced GCp proliferation, cerebellar hypoplasia, developmental delay, and motor deficits in mice. Genome-wide expression profiling revealed downregulated expression of the gene encoding the glycoprotein reelin (Reln) in Chd7-deficient GCps. Recessive RELN mutations have been associated with severe cerebellar hypoplasia in humans. We found molecular and genetic evidence that reductions in Reln expression contribute to GCp proliferative defects and cerebellar hypoplasia in GCp-specific Chd7 mouse mutants. Finally, we showed that CHD7 is necessary for maintaining an open, accessible chromatin state at the Reln locus. Taken together, this study shows that Reln gene expression is regulated by chromatin remodeling, identifies CHD7 as a previously unrecognized upstream regulator of Reln, and provides direct in vivo evidence that a mammalian CHD protein can control brain development by modulating chromatin accessibility in neuronal progenitors. PMID:28165338

  15. Changes in the cerebellar and cerebro-cerebellar circuit in type 2 diabetes.

    Science.gov (United States)

    Fang, Peng; An, Jie; Tan, Xin; Zeng, Ling-Li; Shen, Hui; Qiu, Shijun; Hu, Dewen

    2017-01-11

    Currently, 422 million adults suffer from diabetes worldwide, leading to tremendous disabilities and a great burden to families and society. Functional and structural MRIs have demonstrated that patients with type 2 diabetes mellitus (T2DM) exhibit abnormalities in brain regions in the cerebral cortex. However, the changes of cerebellar anatomical connections in diabetic patients remains unclear. In the current study, diffusion tensor imaging deterministic tractography and statistical analysis were employed to investigate abnormal cerebellar anatomical connections in diabetic patients. This is the first study to investigate the altered cerebellar anatomical connectivity in T2DM patients. Decreased anatomical connections were found in the cerebellar and cerebro-cerebellar circuits of T2DM patients, providing valuable new insights into the potential neuro-pathophysiology of diabetes-related motor and cognitive deficits.

  16. Intraocular lens alignment from an en face optical coherence tomography image Purkinje-like method

    Science.gov (United States)

    Sun, Mengchan; de Castro, Alberto; Ortiz, Sergio; Perez-Merino, Pablo; Birkenfeld, Judith; Marcos, Susana

    2014-06-01

    Measurement of intraocular lens (IOL) alignment implanted in patients in cataract surgery is important to understand their optical performance. We present a method to estimate tilt and decentration of IOLs based on optical coherence tomography (OCT) images. En face OCT images show Purkinje-like images that correspond to the specular reflections from the corneal and IOL surfaces. Unlike in standard Purkinje-imaging, the tomographic nature of OCT allows unequivocal association of the reflection with the corresponding surface. The locations of the Purkinje-like images are linear combinations of IOL tilt, IOL decentration, and eye rotation. The weighting coefficients depend on the individual anterior segment geometry, obtained from the same OCT datasets. The methodology was demonstrated on an artificial model eye with set amounts of lens tilt and decentration and five pseudophakic eyes. Measured tilt and decentration in the artificial eye differed by 3.7% and 0.9%, respectively, from nominal values. In patients, average IOL tilt and decentration from Purkinje were 3.30±4.68 deg and 0.16±0.16 mm, respectively, and differed on average by 0.5 deg and 0.09 mm, respectively, from direct measurements on distortion-corrected OCT images. Purkinje-based methodology from anterior segment en face OCT imaging provided, therefore, reliable measurements of IOL tilt and decentration.

  17. Excitatory effect of histamine on neuronal activity of rat cerebellar fastigial nucleus in vitro

    Institute of Scientific and Technical Information of China (English)

    TANG Biao; ZHANG Jun; LI HongZhao; ZHU JingNing; WANG JianJun

    2007-01-01

    The cerebellar fastigial nucleus (FN) holds an important role in motor control and body balance. Previous studies have revealed that the nucleus is innervated by direct hypothalamocerebellar histaminergic fibers. However, the functional role of histaminergic projection in cerebellar FN has never been established. In this study, we investigated the effect of histamine on neuronal firing of cerebellar FN by using slice preparations. Sixty-five FN cells were recorded from 47 cerebellar slices, and a vast majority of the cells responded to histamine stimulation with an excitatory response (58/65, 89.2%). Perfusing slices with low-Ca2+/high-Mg2+ medium did not block the histamine-induced excitation (n=10), supporting a direct postsynaptic action of histamine on the cells. Furthermore, the excitatory effect of histamine on FN neurons was not blocked by selective histamine H1 receptor antagonist triprolidine (n=15) or chlorpheniramine (n=10), but was effectively suppressed by ranitidine (n=15), a highly selective histamine H2 receptor antagonist. On the other hand, highly selective histamine H2 receptor agonist dimaprit (n=20) instead of histamine H1 receptor agonist 2-pyridylethylamine (n=16) mimicked the excitatory effect of histamine on FN neurons. The dimaprit-induced FN neuronal excitation was effectively antagonized by selective histamine H2 receptor antagonist ranitidine (n=13) but not influenced by selective histamine H1 receptor antagonist triprolidine (n=15). These results demonstrate that histamine excites cerebellar FN cells via the histamine H2 receptor mechanism and suggest that the hypothalamocerebellar histaminergic fibers may modulate cerebellar FN-mediated sensorimotor integration through their excitatory innervations on FN neurons.

  18. 琥珀酸对幼龄大鼠小脑谷氨酸能突触传递的抑制作用%Inhibition of succinic acid on cerebellar glutamatergic synaptic transmission in neonatal rats

    Institute of Scientific and Technical Information of China (English)

    何海燕; 陈静; 晋芙丽; 李凌; 杜永平; 张月萍

    2016-01-01

    目的:探讨琥珀酸( succinic acid,SA)对幼龄大鼠小脑谷氨酸能突触传递的影响。方法采用全细胞膜片钳记录法,在矢状位小脑脑片上记录浦肯野细胞( Purkinje cells,PCs)自发性微小兴奋性突触后电流( miniture excitatory postsynaptic current,mEPSC)和刺激平行纤维( parallel fibre,PF)诱发的PCs兴奋性突触后电位( excitatory postsynaptic potential,EPSP),比较琥珀酸处理前后mEPSC和PF-PC EPSP的变化。结果琥珀酸处理后,幼鼠小脑PCs的自发性mEPSCs幅值显著减小,由给药前的(24.85±2.78)pA减小至给药后的(13.14±0.84)pA,频率也由给药前的(5.04±1.07)Hz降至给药后的(2.77±0.79)Hz,差异均有统计学意义(P<0.01);琥珀酸显著抑制了PF-PC EPSPs的幅值,使其降低至用药前的(37.76±1.10)%(P<0.01),并使EPSP双脉冲(paired-pulse facilitation,PPF)增强的比率较用药前增加了(40.26±2.9)%(P<0.01),差异均有统计学意义。结论琥珀酸对幼龄大鼠小脑谷氨酸能突触传递有显著的抑制作用。%Objective To investigate the effects of succinic acid( SA) on the glutamatergic synaptic transmission in the neonatal rat cerebellum. Methods The whole-cell patch-clamp technique was carried out in Purkinje cells( PCs) of sagittal cerebellar slices to record the spontaneous miniture excitatory postsynaptic current(mEPSC) and the excitatory postsynaptic potential(EPSP) induced by parallel fiber( PF) stimulation. The changes of the mEPSC and the PF-PC EPSP upon SA were analyzed before and after SA perfusion. Results SA significantly reduced the amplitude[from(24.85 ±2.78)pA to(13.14 ±0.84)pA,P<0.01]and the frequency[from (5.04 ±1.07)Hz to (2.77 ±0.79)Hz,P<0.01] of the spontaneous mEPSCs. SA also significantly inhibited PF-PC EPSPs ampli-tude to (37. 76 ± 1. 10)% of the control(P<0. 01) and enhanced the EPSP paired-pulse facilitation(PPF) by(40. 26 ± 2. 9)%(P<0. 01). Conclusion SA may provide an inhibitory effect on cerebellar

  19. Characterization of depolarization-coupled release of glutamate from cultured mouse cerebellar granule cells using DL-threo-beta-benzyloxyaspartate (DL-TBOA) to distinguish between the vesicular and cytoplasmic pools

    DEFF Research Database (Denmark)

    Bak, Lasse K; Schousboe, Arne; Waagepetersen, Helle S

    2003-01-01

    Release of preloaded [3H]D-aspartate in response to depolarization induced by N-methyl-D-aspartate (NMDA) or the endogenous agonist glutamate was characterized using cultured glutamatergic cerebellar granule neurons. Release from the vesicular and the cytoplasmic glutamate pools, respectively, wa...

  20. Oral administration of PF-01247324, a subtype-selective Nav1.8 blocker, reverses cerebellar deficits in a mouse model of multiple sclerosis.

    Directory of Open Access Journals (Sweden)

    Shannon D Shields

    Full Text Available Cerebellar symptoms significantly diminish quality of life in patients with multiple sclerosis (MS. We previously showed that sodium channel Nav1.8, although normally restricted to peripheral somatosensory neurons, is upregulated in the cerebellum in MS, and that Nav1.8 expression is linked to ataxia and MS-like symptoms in mice. Furthermore, intracerebroventricular administration of the Nav1.8 blocker A-803467 temporarily reversed electrophysiological and behavioral manifestations of disease in a mouse MS model; unfortunately A-803467 is not orally bioavailable, diminishing the potential for translation to human patients. In the present study, we assessed the effect of per os (p.o. dosing of a new orally bioavailable Nav1.8-selective blocker, PF-01247324, in transgenic mice expressing Nav1.8 in Purkinje neurons, and in wildtype mice in the experimental autoimmune encephalomyelitis (EAE model. PF-01247324 was administered by oral gavage at 1000 mg/kg; control groups received an equal volume of vehicle. Behavioral assays of motor coordination, grip strength, and ataxia were performed. We observed significant improvements in motor coordination and cerebellar-like symptoms in mice that received PF-01247324 compared to control littermates that received vehicle. These preclinical proof-of-concept data suggest that PF-01247324, its derivatives, or other Nav1.8-selective blockers merit further study for providing symptomatic therapy for cerebellar dysfunction in MS and related disorders.

  1. Deficiency of the miR-29a/b-1 cluster leads to ataxic features and cerebellar alterations in mice

    DEFF Research Database (Denmark)

    Papadopoulou, Aikaterini S; Serneels, Lutgarde; Achsel, Tilmann;

    2015-01-01

    to their wildtype littermates. In addition, a decreased number of parallel fibers form synapses on the Purkinje cells. We identified several mRNAs significantly up-regulated in the absence of the miR-29a/b-1 cluster. At the protein level, however, the voltage-gated potassium channel Kcnc3 (Kv3.3) was significantly...

  2. GABA agonist induced changes in ultrastructure and GABA receptor expression in cerebellar granule cells is linked to hyperpolarization of the neurons

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, Gert Helge; Schousboe, A

    1990-01-01

    treatment did not lead to formation of low affinity GABA receptors. Studies of the ultrastructure of the cells (4-day-old cultures) showed that exposure to bromide or valinomycin mimicked the ability of THIP to enhance the cytoplasmic density of rough endoplasmic reticulum, Golgi apparatus, vesicles...

  3. Expression of the GABA(A) receptor alpha6 subunit in cultured cerebellar granule cells is developmentally regulated by activation of GABA(A) receptors

    DEFF Research Database (Denmark)

    Carlson, B X; Belhage, B; Hansen, Gert Helge

    1997-01-01

    , no significant change in [3H]Ro15-4513 binding was observed for the 56-kDa polypeptide. Immunolabeling of the alpha6 subunit using silver-enhanced, immuno-gold staining of granule cells showed a significant effect with THIP treatment only at 4 DIV and not at 8 DIV. Examination by light microscopy demonstrated...

  4. Lipid raft localization of GABA A receptor and Na+, K+-ATPase in discrete microdomain clusters in rat cerebellar granule cells

    DEFF Research Database (Denmark)

    Dalskov, Stine-Mathilde; Immerdal, Lissi; Niels-Christiansen, Lise-Lotte W;

    2005-01-01

    , reflecting clustering of the two proteins in separate membrane microdomains. Both proteins were observed in patchy "hot spots" at the cell surface as well as in isolated lipid rafts. Their insolubility in Brij 98 was only marginally affected by methyl-beta-cyclodextrin. In contrast, both the GABA(A) receptor...

  5. Metabolic anatomy of paraneoplastic cerebellar degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, N.E.; Posner, J.B.; Sidtis, J.J.; Moeller, J.R.; Strother, S.C.; Dhawan, V.; Rottenberg, D.A.

    1988-06-01

    Eleven patients with acquired cerebellar degeneration (10 of whom had paraneoplastic cerebellar degeneration (PCD)) were evaluated using neuropsychological tests and /sup 18/F-fluorodeoxyglucose/positron emission tomography to (1) quantify motor, cognitive, and metabolic abnormalities; (2) determine if characteristic alterations in the regional cerebral metabolic rate for glucose (rCMRGlc) are associated with PCD; and (3) correlate behavioral and metabolic measures of disease severity. Eighteen volunteer subjects served as normal controls. Although some PCD neuropsychological test scores were abnormal, these results could not, in general, be dissociated from the effects of dysarthria and ataxia. rCMRGlc was reduced in patients with PCD (versus normal control subjects) in all regions except the brainstem. Analysis of patient and control rCMRGlc data using a mathematical model of regional metabolic interactions revealed two metabolic pattern descriptors, SSF1 and SSF2, which distinguished patients with PCD from normal control subjects; SSF2, which described a metabolic coupling between cerebellum, cuneus, and posterior temporal, lateral frontal, and paracentral cortex, correlated with quantitative indices of cerebellar dysfunction. Our inability to document substantial intellectual impairment in 7 of 10 patients with PCD contrasts with the 50% incidence of dementia in PCD reported by previous investigators. Widespread reductions in PCD rCMRGlc may result from the loss of cerebellar efferents to thalamus and forebrain structures, a reverse cerebellar diaschisis.

  6. RNAi silencing of P/Q-type calcium channels in Purkinje neurons of adult mouse leads to episodic ataxia type 2.

    Science.gov (United States)

    Salvi, Julie; Bertaso, Federica; Mausset-Bonnefont, Anne-Laure; Metz, Alexandra; Lemmers, Céline; Ango, Fabrice; Fagni, Laurent; Lory, Philippe; Mezghrani, Alexandre

    2014-08-01

    Episodic ataxia type-2 (EA2) is a dominantly inherited human neurological disorder caused by loss of function mutations in the CACNA1A gene, which encodes the CaV2.1 subunit of P/Q-type voltage-gated calcium channels. It remains however unknown whether the deficit of cerebellar CaV2.1 in adult is in direct link with the disease. To address this issue, we have used lentiviral based-vector RNA interference (RNAi) to knock-down CaV2.1 expression in the cerebellum of adult mice. We show that suppression of the P/Q-type channels in Purkinje neurons induced motor abnormalities, such as imbalance and ataxic gait. Interestingly, moderate channel suppression caused no basal ataxia, while β-adrenergic activation and exercise mimicked stress induced motor disorders. Moreover, stress-induced ataxia was stable, non-progressive and totally abolished by acetazolamide, a carbonic anhydrase inhibitor used to treat EA2. Altogether, these data reveal that P/Q-type channel suppression in adult mice supports the episodic status of EA2 disease.

  7. Genetics Home Reference: autosomal recessive cerebellar ataxia type 1

    Science.gov (United States)

    ... Genetics Home Health Conditions ARCA1 autosomal recessive cerebellar ataxia type 1 Enable Javascript to view the expand/ ... Open All Close All Description Autosomal recessive cerebellar ataxia type 1 ( ARCA1 ) is a condition characterized by ...

  8. Landmark based shape analysis for cerebellar ataxia classification and cerebellar atrophy pattern visualization

    Science.gov (United States)

    Yang, Zhen; Abulnaga, S. Mazdak; Carass, Aaron; Kansal, Kalyani; Jedynak, Bruno M.; Onyike, Chiadi; Ying, Sarah H.; Prince, Jerry L.

    2016-03-01

    Cerebellar dysfunction can lead to a wide range of movement disorders. Studying the cerebellar atrophy pattern associated with different cerebellar disease types can potentially help in diagnosis, prognosis, and treatment planning. In this paper, we present a landmark based shape analysis pipeline to classify healthy control and different ataxia types and to visualize the characteristic cerebellar atrophy patterns associated with different types. A highly informative feature representation of the cerebellar structure is constructed by extracting dense homologous landmarks on the boundary surfaces of cerebellar sub-structures. A diagnosis group classifier based on this representation is built using partial least square dimension reduction and regularized linear discriminant analysis. The characteristic atrophy pattern for an ataxia type is visualized by sampling along the discriminant direction between healthy controls and the ataxia type. Experimental results show that the proposed method can successfully classify healthy controls and different ataxia types. The visualized cerebellar atrophy patterns were consistent with the regional volume decreases observed in previous studies, but the proposed method provides intuitive and detailed understanding about changes of overall size and shape of the cerebellum, as well as that of individual lobules.

  9. Hypoxic preconditioning differentially affects GABAergic and glutamatergic neuronal cells in the injured cerebellum of the neonatal rat.

    Directory of Open Access Journals (Sweden)

    Sergio G Benitez

    Full Text Available In this study we examined cerebellar alterations in a neonatal rat model of hypoxic-ischemic brain injury with or without hypoxic preconditioning (Pc. Between postnatal days 7 and 15, the cerebellum is still undergoing intense cellular proliferation, differentiation and migration, dendritogenesis and synaptogenesis. The expression of glutamate decarboxylase 1 (GAD67 and the differentiation factor NeuroD1 were examined as markers of Purkinje and granule cells, respectively. We applied quantitative immunohistochemistry to sagittal cerebellar slices, and Western blot analysis of whole cerebella obtained from control (C rats and rats submitted to Pc, hypoxia-ischemia (L and a combination of both treatments (PcL. We found that either hypoxia-ischemia or Pc perturbed the granule cells in the posterior lobes, affecting their migration and final placement in the internal granular layer. These effects were partially attenuated when the Pc was delivered prior to the hypoxia-ischemia. Interestingly, whole nuclear NeuroD1 levels in Pc animals were comparable to those in the C rats. However, a subset of Purkinje cells that were severely affected by the hypoxic-ischemic insult--showing signs of neuronal distress at the levels of the nucleus, cytoplasm and dendritic arborization--were not protected by Pc. A monoclonal antibody specific for GAD67 revealed a three-band pattern in cytoplasmic extracts from whole P15 cerebella. A ∼110 kDa band, interpreted as a potential homodimer of a truncated form of GAD67, was reduced in Pc and L groups while its levels were close to the control animals in PcL rats. Additionally we demonstrated differential glial responses depending on the treatment, including astrogliosis in hypoxiated cerebella and a selective effect of hypoxia-ischemia on the vimentin-immunolabeled intermediate filaments of the Bergmann glia. Thus, while both glutamatergic and GABAergic cerebellar neurons are compromised by the hypoxic-ischemic insult

  10. Differential distribution of GABAA receptor subunits in soma and processes of cerebellar granule cells: effects of maturation and a GABA agonist

    DEFF Research Database (Denmark)

    Elster, L; Hansen, Gert Helge; Belhage, B;

    1995-01-01

    or absence of the GABAA receptor agonist 4,5,6,7-tetrahydroisoxazolo[5,4c]pyridin-3-ol (THIP). THIP (150 microM) induced a 2-fold increase in the number of alpha 1 and beta 2/3 subunits in both cell bodies and processes in 4-day-old cultures. Extending the culture period to 8 days led to a polarization...... composition. Interestingly, receptor subunit clusters, consisting of alpha 1 alone, were more frequently observed than composite (alpha 1; beta 2/3) clusters. This substantiates the view that receptors not having alpha 1 and beta 2/3 subunits in the same complex may exist....

  11. A probabilistic atlas of the cerebellar white matter

    NARCIS (Netherlands)

    Baarsen, K.M. van; Kleinnijenhuis, M.; Jbabdi, S.; Sotiropoulos, S.N.; Grotenhuis, J.A.; Cappellen van Walsum, A.M. van

    2016-01-01

    Imaging of the cerebellar cortex, deep cerebellar nuclei and their connectivity are gaining attraction, due to the important role the cerebellum plays in cognition and motor control. Atlases of the cerebellar cortex and nuclei are used to locate regions of interest in clinical and neuroscience studi

  12. Rhythmic finger tapping reveals cerebellar dysfunction in essential tremor

    NARCIS (Netherlands)

    Buijink, A. W. G.; Broersma, M.; van der Stouwe, A. M. M.; van Wingen, G. A.; Groot, P. F. C.; Speelman, J. D.; Maurits, N. M.; van Rootselaar, A. F.

    2015-01-01

    Introduction: Cerebellar circuits are hypothesized to play a central role in the pathogenesis of essential tremor. Rhythmic finger tapping is known to strongly engage the cerebellar motor circuitry. We characterize cerebellar and, more specifically, dentate nucleus function, and neural correlates of

  13. 21 CFR 882.5820 - Implanted cerebellar stimulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted cerebellar stimulator. 882.5820 Section... (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5820 Implanted cerebellar stimulator. (a) Identification. An implanted cerebellar stimulator is a device used to...

  14. Paraneoplastic cerebellar dysfunction in Hodgkin's lymphoma

    Directory of Open Access Journals (Sweden)

    Kazi Sazzad Manir

    2015-01-01

    Full Text Available Paraneoplastic cerebellar degeneration (PCD is a rare presentation of Hodgkin's Lymphoma (HL manifests as acute/sub-acute nature. We report a case of 21 yr old male presented with acute cerebellar signs along with underlying HL.MRI brain was normal. CSF study was unremarkable. Patient was treated with six cycles of chemotherapy followed by radiotherapy. Neurological manifestations remarkably improved along with complete resolution of underlying HL. Anti-cancer therapy of underlying HL is the main strategy of treating associated PCD.

  15. Similar cation channels mediate protection from cerebellar exitotoxicity by exercise and inheritance.

    Science.gov (United States)

    Ben-Ari, Shani; Ofek, Keren; Barbash, Shahar; Meiri, Hanoch; Kovalev, Eugenia; Greenberg, David Samuel; Soreq, Hermona; Shoham, Shai

    2012-03-01

    Exercise and inherited factors both affect recovery from stroke and head injury, but the underlying mechanisms and interconnections between them are yet unknown. Here, we report that similar cation channels mediate the protective effect of exercise and specific genetic background in a kainate injection model of cerebellar stroke. Microinjection to the cerebellum of the glutamatergic agonist, kainate, creates glutamatergic excito\\xE2\\x80\\x90toxicity characteristic of focal stroke, head injury or alcoholism. Inherited protection and prior exercise were both accompanied by higher cerebellar expression levels of the Kir6.1 ATP-dependent potassium channel in adjacent Bergmann glia, and voltage-gated KVbeta2 and cyclic nucleotide-gated cation HCN1 channels in basket cells. Sedentary FVB/N and exercised C57BL/6 mice both expressed higher levels of these cation channels compared to sedentary C57BL/6 mice, and were both found to be less sensitive to glutamate toxicity. Moreover, blocking ATP-dependent potassium channels with Glibenclamide enhanced kainate-induced cell death in cerebellar slices from the resilient sedentary FVB/N mice. Furthermore, exercise increased the number of acetylcholinesterase-positive fibres in the molecular layer, reduced cerebellar cytokine levels and suppressed serum acetylcholinesterase activity, suggesting anti-inflammatory protection by enhanced cholinergic signalling. Our findings demonstrate for the first time that routine exercise and specific genetic backgrounds confer protection from cerebellar glutamatergic damages by similar molecular mechanisms, including elevated expression of cation channels. In addition, our findings highlight the involvement of the cholinergic anti-inflammatory pathway in insult-inducible cerebellar processes. These mechanisms are likely to play similar roles in other brain regions and injuries as well, opening new venues for targeted research efforts.

  16. Developmental disorders of the brain can be caused by PCBs; low doses of hydroxy-PCBs disrupt thyroid hormone-dependent dendrite formation from Purkinje neurons in culture

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, Y.; Kimura-Kuroda, J. [Tokyo Metropol. Inst. for Neuroscience, Tokyo (Japan); Nagata, I. [CREST/ JST, Tokyo (Japan)

    2004-09-15

    Exposure to some environmental chemicals during the perinatal period causes developmental disorders of the brain. Cognitive impairment and hyperactivity in infants were reported in Taiwan, known as Yu-cheng incidents caused by the accidental contamination of polychlorinated biphenyls (PCBs). Together with recent experimental data, Kuroda proposes a hypothesis that spatio-temporal disruptions of developing neuronal circuits by PCB exposure can cause the comobidity of learning disorders (LD), attention deficit hyperactivity disorder (ADHD) and autsm with the co-exposure to other environmental chemicals. PCBs and hydroxylated PCBs (OH-PCBs) have similar chemical structures to thyroid hormones (TH), thyroxine (T4) and triiodothyronine (T3). TH deficiency in the perinatal period causes cretinism children with severe cognitive and mental retardation. In primate model, Rice demonstrates that postnatal exposure to PCBs can dramatically influence later behavioral function. Epidemiological studies also indicate the possible developmental neurotoxicity of PCBs accumulated in human bodies. However, the precise underlying mechanisms and which types of PCB or OH-PCB with such effects have yet to be elucidated. It is important to establish a simple, reproducible, and sensitive in vitro assay for determining the effects of PCBs and OH-PCBs on the development of the central nervous system. Recently Iwasaki et al. established a reporter assay system and disclosed that low doses of PCBs potentially interfere TH-dependent gene expressions. This is the first demonstration that PCBs and OH-PCBs directly affect TH-receptor (TR)-mediated gene expressions crucial to the brain development, through unique mechanism. We also have demonstrated TH-dependent development of Purkinje neurons in vitro using a serum-free chemically defined medium. The degree of dendritic development of Purkinje cells is TH dose-dependent and exhibits high sensitivity in the pM order. Therefore, in the present study

  17. Non-progressive cerebellar ataxia and previous undetermined acute cerebellar injury: a mysterious clinical condition

    Directory of Open Access Journals (Sweden)

    Wladimir Bocca Vieira de Rezende Pinto

    2015-01-01

    Full Text Available Cerebellar ataxias represent a wide group of neurological diseases secondary to dysfunctions of cerebellum or its associated pathways, rarely coursing with acute-onset acquired etiologies and chronic non-progressive presentation. We evaluated patients with acquired non-progressive cerebellar ataxia that presented previous acute or subacute onset. Clinical and neuroimaging characterization of adult patients with acquired non-progressive ataxia were performed. Five patients were identified with the phenotype of acquired non-progressive ataxia. Most patients presented with a juvenile to adult-onset acute to subacute appendicular and truncal cerebellar ataxia with mild to moderate cerebellar or olivopontocerebellar atrophy. Establishing the etiology of the acute triggering events of such ataxias is complex. Non-progressive ataxia in adults must be distinguished from hereditary ataxias.

  18. Non-progressive cerebellar ataxia and previous undetermined acute cerebellar injury: a mysterious clinical condition

    Directory of Open Access Journals (Sweden)

    Wladimir Bocca Vieira de Rezende Pinto

    2015-10-01

    Full Text Available Cerebellar ataxias represent a wide group of neurological diseases secondary to dysfunctions of cerebellum or its associated pathways, rarely coursing with acute-onset acquired etiologies and chronic non-progressive presentation. We evaluated patients with acquired non-progressive cerebellar ataxia that presented previous acute or subacute onset. Clinical and neuroimaging characterization of adult patients with acquired non-progressive ataxia were performed. Five patients were identified with the phenotype of acquired non-progressive ataxia. Most patients present