1
|
Monteverdi A, Di Domenico D, D'Angelo E, Mapelli L. Anisotropy and Frequency Dependence of Signal Propagation in the Cerebellar Circuit Revealed by High-Density Multielectrode Array Recordings. Biomedicines 2023; 11:biomedicines11051475. [PMID: 37239146 DOI: 10.3390/biomedicines11051475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/05/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
The cerebellum is one of the most connected structures of the central nervous system and receives inputs over an extended frequency range. Nevertheless, the frequency dependence of cerebellar cortical processing remains elusive. In this work, we characterized cerebellar cortex responsiveness to mossy fibers activation at different frequencies and reconstructed the spread of activity in the sagittal and coronal planes of acute mouse cerebellar slices using a high-throughput high-density multielectrode array (HD-MEA). The enhanced spatiotemporal resolution of HD-MEA revealed the frequency dependence and spatial anisotropy of cerebellar activation. Mossy fiber inputs reached the Purkinje cell layer even at the lowest frequencies, but the efficiency of transmission increased at higher frequencies. These properties, which are likely to descend from the topographic organization of local inhibition, intrinsic electroresponsiveness, and short-term synaptic plasticity, are critical elements that have to be taken into consideration to define the computational properties of the cerebellar cortex and its pathological alterations.
Collapse
Affiliation(s)
- Anita Monteverdi
- Brain Connectivity Center, IRCCS Mondino Foundation, 27100 Pavia, Italy
| | - Danila Di Domenico
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy
| | - Egidio D'Angelo
- Brain Connectivity Center, IRCCS Mondino Foundation, 27100 Pavia, Italy
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy
| | - Lisa Mapelli
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy
| |
Collapse
|
2
|
Gagliano G, Monteverdi A, Casali S, Laforenza U, Gandini Wheeler-Kingshott CAM, D’Angelo E, Mapelli L. Non-Linear Frequency Dependence of Neurovascular Coupling in the Cerebellar Cortex Implies Vasodilation-Vasoconstriction Competition. Cells 2022; 11:1047. [PMID: 35326498 PMCID: PMC8947624 DOI: 10.3390/cells11061047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/11/2022] [Accepted: 03/17/2022] [Indexed: 01/28/2023] Open
Abstract
Neurovascular coupling (NVC) is the process associating local cerebral blood flow (CBF) to neuronal activity (NA). Although NVC provides the basis for the blood oxygen level dependent (BOLD) effect used in functional MRI (fMRI), the relationship between NVC and NA is still unclear. Since recent studies reported cerebellar non-linearities in BOLD signals during motor tasks execution, we investigated the NVC/NA relationship using a range of input frequencies in acute mouse cerebellar slices of vermis and hemisphere. The capillary diameter increased in response to mossy fiber activation in the 6-300 Hz range, with a marked inflection around 50 Hz (vermis) and 100 Hz (hemisphere). The corresponding NA was recorded using high-density multi-electrode arrays and correlated to capillary dynamics through a computational model dissecting the main components of granular layer activity. Here, NVC is known to involve a balance between the NMDAR-NO pathway driving vasodilation and the mGluRs-20HETE pathway driving vasoconstriction. Simulations showed that the NMDAR-mediated component of NA was sufficient to explain the time course of the capillary dilation but not its non-linear frequency dependence, suggesting that the mGluRs-20HETE pathway plays a role at intermediate frequencies. These parallel control pathways imply a vasodilation-vasoconstriction competition hypothesis that could adapt local hemodynamics at the microscale bearing implications for fMRI signals interpretation.
Collapse
Affiliation(s)
- Giuseppe Gagliano
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
| | - Anita Monteverdi
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
- IRCCS Mondino Foundation, 27100 Pavia, Italy
| | - Stefano Casali
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
| | - Umberto Laforenza
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy;
| | - Claudia A. M. Gandini Wheeler-Kingshott
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
- IRCCS Mondino Foundation, 27100 Pavia, Italy
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London WC1N3 BG, UK
| | - Egidio D’Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
- IRCCS Mondino Foundation, 27100 Pavia, Italy
| | - Lisa Mapelli
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (G.G.); (A.M.); (S.C.); (C.A.M.G.W.-K.)
| |
Collapse
|
3
|
Tognolina M, Monteverdi A, D’Angelo E. Discovering Microcircuit Secrets With Multi-Spot Imaging and Electrophysiological Recordings: The Example of Cerebellar Network Dynamics. Front Cell Neurosci 2022; 16:805670. [PMID: 35370553 PMCID: PMC8971197 DOI: 10.3389/fncel.2022.805670] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 02/25/2022] [Indexed: 12/02/2022] Open
Abstract
The cerebellar cortex microcircuit is characterized by a highly ordered neuronal architecture having a relatively simple and stereotyped connectivity pattern. For a long time, this structural simplicity has incorrectly led to the idea that anatomical considerations would be sufficient to understand the dynamics of the underlying circuitry. However, recent experimental evidence indicates that cerebellar operations are much more complex than solely predicted by anatomy, due to the crucial role played by neuronal and synaptic properties. To be able to explore neuronal and microcircuit dynamics, advanced imaging, electrophysiological techniques and computational models have been combined, allowing us to investigate neuronal ensembles activity and to connect microscale to mesoscale phenomena. Here, we review what is known about cerebellar network organization, neural dynamics and synaptic plasticity and point out what is still missing and would require experimental assessments. We consider the available experimental techniques that allow a comprehensive assessment of circuit dynamics, including voltage and calcium imaging and extracellular electrophysiological recordings with multi-electrode arrays (MEAs). These techniques are proving essential to investigate the spatiotemporal pattern of activity and plasticity in the cerebellar network, providing new clues on how circuit dynamics contribute to motor control and higher cognitive functions.
Collapse
Affiliation(s)
| | - Anita Monteverdi
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- IRCCS Mondino Foundation, Brain Connectivity Center, Pavia, Italy
| | - Egidio D’Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- IRCCS Mondino Foundation, Brain Connectivity Center, Pavia, Italy
| |
Collapse
|
4
|
Alfaro-Ruíz R, Aguado C, Martín-Belmonte A, Moreno-Martínez AE, Luján R. Cellular and Subcellular Localisation of Kv4-Associated KChIP Proteins in the Rat Cerebellum. Int J Mol Sci 2020; 21:ijms21176403. [PMID: 32899153 PMCID: PMC7503578 DOI: 10.3390/ijms21176403] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 08/28/2020] [Accepted: 08/31/2020] [Indexed: 11/29/2022] Open
Abstract
The K+ channel interacting proteins (KChIPs) are a family of cytosolic proteins that interact with Kv4 channels, leading to higher current density, modulation of channel inactivation and faster recovery from inactivation. Using immunohistochemical techniques at the light and electron microscopic level combined with quantitative analysis, we investigated the cellular and subcellular localisation of KChIP3 and KChIP4 to compare their distribution patterns with those for Kv4.2 and Kv4.3 in the cerebellar cortex. Immunohistochemistry at the light microscopic level demonstrated that KChIP3, KChIP4, Kv4.2 and Kv4.3 proteins were widely expressed in the cerebellum, with mostly overlapping patterns. Immunoelectron microscopic techniques showed that KChIP3, KChIP4, Kv4.2 and Kv4.3 shared virtually the same somato-dendritic domains of Purkinje cells and granule cells. Application of quantitative approaches showed that KChIP3 and KChIP4 were mainly membrane-associated, but also present at cytoplasmic sites close to the plasma membrane, in dendritic spines and shafts of Purkinje cells (PCs) and dendrites of granule cells (GCs). Similarly, immunoparticles for Kv4.2 and Kv4.3 were observed along the plasma membrane and at intracellular sites in the same neuron populations. In addition to the preferential postsynaptic distribution, KChIPs and Kv4 were also distributed presynaptically in parallel fibres and mossy fibres. Immunoparticles for KChIP3, KChIP4 and Kv4.3 were detected in parallel fibres, and KChIP3, KChIP4, Kv4.2 and Kv4.3 were found in parallel fibres, indicating that composition of KChIP and Kv4 seems to be input-dependent. Together, our findings unravelled previously uncharacterised KChIP and Kv4 subcellular localisation patterns in neurons, revealed that KChIP have additional Kv4-unrelated functions in the cerebellum and support the formation of macromolecular complexes between KChIP3 and KChIP4 with heterotetrameric Kv4.2/Kv4.3 channels.
Collapse
Affiliation(s)
| | | | | | | | - Rafael Luján
- Correspondence: ; Tel.: +34-967-599200 (ext. 2196)
| |
Collapse
|
5
|
Hyperexcitability and Hyperplasticity Disrupt Cerebellar Signal Transfer in the IB2 KO Mouse Model of Autism. J Neurosci 2019; 39:2383-2397. [PMID: 30696733 DOI: 10.1523/jneurosci.1985-18.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 12/22/2018] [Accepted: 01/08/2019] [Indexed: 12/25/2022] Open
Abstract
Autism spectrum disorders (ASDs) are pervasive neurodevelopmental conditions that often involve mutations affecting synaptic mechanisms. Recently, the involvement of cerebellum in ASDs has been suggested, but the underlying functional alterations remained obscure. We investigated single-neuron and microcircuit properties in IB2 (Islet Brain-2) KO mice of either sex. The IB2 gene (chr22q13.3 terminal region) deletion occurs in virtually all cases of Phelan-McDermid syndrome, causing autistic symptoms and a severe delay in motor skill acquisition. IB2 KO granule cells showed a larger NMDA receptor-mediated current and enhanced intrinsic excitability, raising the excitatory/inhibitory balance. Furthermore, the spatial organization of granular layer responses to mossy fibers shifted from a "Mexican hat" to a "stovepipe hat" profile, with stronger excitation in the core and weaker inhibition in the surround. Finally, the size and extension of long-term synaptic plasticity were remarkably increased. These results show for the first time that hyperexcitability and hyperplasticity disrupt signal transfer in the granular layer of IB2 KO mice, supporting cerebellar involvement in the pathogenesis of ASD.SIGNIFICANCE STATEMENT This article shows for the first time a complex set of alterations in the cerebellum granular layer of a mouse model [IB2 (Islet Brain-2) KO] of autism spectrum disorders. The IB2 KO in mice mimics the deletion of the corresponding gene in the Phelan-McDermid syndrome in humans. The changes reported here are centered on NMDA receptor hyperactivity, hyperplasticity, and hyperexcitability. These, in turn, increase the excitatory/inhibitory balance and alter the shape of center/surround structures that emerge in the granular layer in response to mossy fiber activity. These results support recent theories suggesting the involvement of cerebellum in autism spectrum disorders.
Collapse
|
6
|
Parasuram H, Nair B, Naldi G, D'Angelo E, Diwakar S. Understanding Cerebellum Granular Layer Network Computations through Mathematical Reconstructions of Evoked Local Field Potentials. Ann Neurosci 2017; 25:11-24. [PMID: 29887679 DOI: 10.1159/000481905] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 09/05/2017] [Indexed: 12/27/2022] Open
Abstract
Background The cerebellar granular layer input stage of cerebellum receives information from tactile and sensory regions of the body. The somatosensory activity in the cerebellar granular layer corresponds to sensory and tactile input has been observed by recording Local Field Potential (LFP) from the Crus-IIa regions of cerebellum in brain slices and in anesthetized animals. Purpose In this paper, a detailed biophysical model of Wistar rat cerebellum granular layer network model and LFP modelling schemas were used to simulate circuit's evoked response. Methods Point Source Approximation and Line Source Approximation were used to reconstruct the network LFP. The LFP mechanism in in vitro was validated in network model and generated the in vivo LFP using the same mechanism. Results The network simulations distinctly displayed the Trigeminal and Cortical (TC) wave components generated by 2 independent bursts implicating the generation of TC waves by 2 independent granule neuron populations. Induced plasticity was simulated to estimate granule neuron activation related population responses. As a prediction, cerebellar dysfunction (ataxia) was also studied using the model. Dysfunction at individual neurons in the network was affected by the population response. Conclusion Our present study utilizes available knowledge on known mechanisms in a single cell and associates network function to population responses.
Collapse
Affiliation(s)
- Harilal Parasuram
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham (Amrita University), Kollam, India
| | - Bipin Nair
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham (Amrita University), Kollam, India
| | - Giovanni Naldi
- Department of Mathematics, University of Milan, Milan, Italy
| | - Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.,Brain Connectivity Center, C. Mondino National Neurological Institute, Pavia, Italy
| | - Shyam Diwakar
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham (Amrita University), Kollam, India
| |
Collapse
|
7
|
Long-Term Potentiation at the Mossy Fiber-Granule Cell Relay Invokes Postsynaptic Second-Messenger Regulation of Kv4 Channels. J Neurosci 2017; 36:11196-11207. [PMID: 27807163 DOI: 10.1523/jneurosci.2051-16.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/12/2016] [Indexed: 11/21/2022] Open
Abstract
Mossy fiber afferents to cerebellar granule cells form the primary synaptic relay into cerebellum, providing an ideal site to process signal inputs differentially. Mossy fiber input is known to exhibit a long-term potentiation (LTP) of synaptic efficacy through a combination of presynaptic and postsynaptic mechanisms. However, the specific postsynaptic mechanisms contributing to LTP of mossy fiber input is unknown. The current study tested the hypothesis that LTP induces a change in intrinsic membrane excitability of rat cerebellar granule cells through modification of Kv4 A-type potassium channels. We found that theta-burst stimulation of mossy fiber input in lobule 9 granule cells lowered the current threshold to spike and increases the gain of spike firing by 2- to 3-fold. The change in postsynaptic excitability was traced to hyperpolarizing shifts in both the half-inactivation and half-activation potentials of Kv4 that occurred upon coactivating NMDAR and group I metabotropic glutamatergic receptors. The effects of theta-burst stimulation on Kv4 channel control of the gain of spike firing depended on a signaling cascade leading to extracellular signal-related kinase activation. Under physiological conditions, LTP of synaptically evoked spike output was expressed preferentially for short bursts characteristic of sensory input, helping to shape signal processing at the mossy fiber-granule cell relay. SIGNIFICANCE STATEMENT Cerebellar granule cells receive mossy fiber inputs that convey information on different sensory modalities and feedback from descending cortical projections. Recent work suggests that signal processing across multiple cerebellar lobules is controlled differentially by postsynaptic ionic mechanisms at the level of granule cells. We found that long-term potentiation (LTP) of mossy fiber input invoked a large increase in granule cell excitability by modifying the biophysical properties of Kv4 channels through a specific signaling cascade. LTP of granule cell output became evident in response to bursts of mossy fiber input, revealing that Kv4 control of intrinsic excitability is modified to respond most effectively to patterns of afferent input that are characteristic of physiological sensory patterns.
Collapse
|
8
|
Gandolfi D, Cerri S, Mapelli J, Polimeni M, Tritto S, Fuzzati-Armentero MT, Bigiani A, Blandini F, Mapelli L, D'Angelo E. Activation of the CREB/ c-Fos Pathway during Long-Term Synaptic Plasticity in the Cerebellum Granular Layer. Front Cell Neurosci 2017; 11:184. [PMID: 28701927 PMCID: PMC5487453 DOI: 10.3389/fncel.2017.00184] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/16/2017] [Indexed: 12/22/2022] Open
Abstract
The induction of long-term potentiation and depression (LTP and LTD) is thought to trigger gene expression and protein synthesis, leading to consolidation of synaptic and neuronal changes. However, while LTP and LTD have been proposed to play important roles for sensori-motor learning in the cerebellum granular layer, their association with these mechanisms remained unclear. Here, we have investigated phosphorylation of the cAMP-responsive element binding protein (CREB) and activation of the immediate early gene c-Fos pathway following the induction of synaptic plasticity by theta-burst stimulation (TBS) in acute cerebellar slices. LTP and LTD were localized using voltage-sensitive dye imaging (VSDi). At two time points following TBS (15 min and 120 min), corresponding to the early and late phases of plasticity, slices were fixed and processed to evaluate CREB phosphorylation (P-CREB) and c-FOS protein levels, as well as Creb and c-Fos mRNA expression. High levels of P-CREB and Creb/c-Fos were detected before those of c-FOS, as expected if CREB phosphorylation triggered gene expression followed by protein synthesis. No differences between control slices and slices stimulated with TBS were observed in the presence of an N-methyl-D-aspartate receptor (NMDAR) antagonist. Interestingly, activation of the CREB/c-Fos system showed a relevant degree of colocalization with long-term synaptic plasticity. These results show that NMDAR-dependent plasticity at the cerebellum input stage bears about transcriptional and post-transcriptional processes potentially contributing to cerebellar learning and memory consolidation.
Collapse
Affiliation(s)
- Daniela Gandolfi
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy.,Brain Connectivity Center, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS)Pavia, Italy
| | - Silvia Cerri
- Laboratory of Functional Neurochemistry, Center for Research in Neurodegenerative Diseases, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS)Pavia, Italy
| | - Jonathan Mapelli
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy.,Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology, University of Modena and Reggio EmiliaModena, Italy
| | - Mariarosa Polimeni
- Department of Public Health, Experimental and Forensic Medicine, Human Anatomy Unit, University of PaviaPavia Italy
| | - Simona Tritto
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy
| | - Marie-Therese Fuzzati-Armentero
- Laboratory of Functional Neurochemistry, Center for Research in Neurodegenerative Diseases, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS)Pavia, Italy
| | - Albertino Bigiani
- Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology, University of Modena and Reggio EmiliaModena, Italy
| | - Fabio Blandini
- Laboratory of Functional Neurochemistry, Center for Research in Neurodegenerative Diseases, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS)Pavia, Italy
| | - Lisa Mapelli
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy.,Museo Storico Della Fisica e Centro Studi e Ricerche Enrico FermiRome, Italy
| | - Egidio D'Angelo
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy.,Brain Connectivity Center, Fondazione Istituto Neurologico Nazionale Casimiro Mondino (IRCCS)Pavia, Italy
| |
Collapse
|
9
|
Colnaghi S, Colagiorgio P, Versino M, Koch G, D'Angelo E, Ramat S. A role for NMDAR-dependent cerebellar plasticity in adaptive control of saccades in humans. Brain Stimul 2017; 10:817-827. [PMID: 28501325 DOI: 10.1016/j.brs.2017.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 05/02/2017] [Accepted: 05/03/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Saccade pulse amplitude adaptation is mediated by the dorsal cerebellar vermis and fastigial nucleus. Long-term depression at the parallel fibre-Purkinjie cell synapses has been suggested to provide a cellular mechanism for the corresponding learning process. The mechanisms and sites of this plasticity, however, are still debated. OBJECTIVE To test the role of cerebellar plasticity phenomena on adaptive saccade control. METHODS We evaluated the effect of continuous theta burst stimulation (cTBS) over the posterior vermis on saccade amplitude adaptation and spontaneous recovery of the initial response. To further identify the substrate of synaptic plasticity responsible for the observed adaptation impairment, subjects were pre-treated with memantine, an N-methyl-d-aspartate receptor (NMDAR) antagonist. RESULTS Amplitude adaptation was altered by cTBS, suggesting that cTBS interferes with cerebellar plasticity involved in saccade adaptation. Amplitude adaptation and spontaneous recovery were not affected by cTBS when recordings were preceded by memantine administration. CONCLUSION The effects of cTBS are NMDAR-dependent and are likely to involve long-term potentiation or long-term depression at specific synaptic connections of the granular and molecular layer, which could effectively take part in cerebellar motor learning.
Collapse
Affiliation(s)
- S Colnaghi
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Via Forlanini 2, 27100 Pavia, Italy; Laboratory of Neuro-otology and Neuro-ophtalmology, C. Mondino National Neurological Institute, via Mondino 2, 27100 Pavia, Italy.
| | - P Colagiorgio
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
| | - M Versino
- Laboratory of Neuro-otology and Neuro-ophtalmology, C. Mondino National Neurological Institute, via Mondino 2, 27100 Pavia, Italy; Department of Brain and Behavioral Sciences, University of Pavia, via Forlanini 6, 27100 Pavia, Italy
| | - G Koch
- Laboratorio di Neurologia Clinica e Comportamentale, Fondazione S. Lucia IRCCS, via Ardeatina 306, 00179 Rome, Italy; Dipartimento di Neurologia, Policlinico Tor Vergata, viale Oxford 81, 00133 Rome, Italy
| | - E D'Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, via Forlanini 6, 27100 Pavia, Italy; Brain Connectivity Center, C. Mondino National Neurological Institute, via Mondino 2, 27100 Pavia, Italy
| | - S Ramat
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
| |
Collapse
|
10
|
Exploring the significance of morphological diversity for cerebellar granule cell excitability. Sci Rep 2017; 7:46147. [PMID: 28406156 PMCID: PMC5390267 DOI: 10.1038/srep46147] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 03/13/2017] [Indexed: 11/09/2022] Open
Abstract
The relatively simple and compact morphology of cerebellar granule cells (CGCs) has led to the view that heterogeneity in CGC shape has negligible impact upon the integration of mossy fibre (MF) information. Following electrophysiological recording, 3D models were constructed from high-resolution imaging data to identify morphological features that could influence the coding of MF input patterns by adult CGCs. Quantification of MF and CGC morphology provided evidence that CGCs could be connected to the multiple rosettes that arise from a single MF input. Predictions from our computational models propose that MF inputs could be more densely encoded within the CGC layer than previous models suggest. Moreover, those MF signals arriving onto the dendrite closest to the axon will generate greater CGC excitation. However, the impact of this morphological variability on MF input selectivity will be attenuated by high levels of CGC inhibition providing further flexibility to the MF → CGC pathway. These features could be particularly important when considering the integration of multimodal MF sensory input by individual CGCs.
Collapse
|
11
|
D'Angelo E, Mapelli L, Casellato C, Garrido JA, Luque N, Monaco J, Prestori F, Pedrocchi A, Ros E. Distributed Circuit Plasticity: New Clues for the Cerebellar Mechanisms of Learning. THE CEREBELLUM 2016; 15:139-51. [PMID: 26304953 DOI: 10.1007/s12311-015-0711-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The cerebellum is involved in learning and memory of sensory motor skills. However, the way this process takes place in local microcircuits is still unclear. The initial proposal, casted into the Motor Learning Theory, suggested that learning had to occur at the parallel fiber-Purkinje cell synapse under supervision of climbing fibers. However, the uniqueness of this mechanism has been questioned, and multiple forms of long-term plasticity have been revealed at various locations in the cerebellar circuit, including synapses and neurons in the granular layer, molecular layer and deep-cerebellar nuclei. At present, more than 15 forms of plasticity have been reported. There has been a long debate on which plasticity is more relevant to specific aspects of learning, but this question turned out to be hard to answer using physiological analysis alone. Recent experiments and models making use of closed-loop robotic simulations are revealing a radically new view: one single form of plasticity is insufficient, while altogether, the different forms of plasticity can explain the multiplicity of properties characterizing cerebellar learning. These include multi-rate acquisition and extinction, reversibility, self-scalability, and generalization. Moreover, when the circuit embeds multiple forms of plasticity, it can easily cope with multiple behaviors endowing therefore the cerebellum with the properties needed to operate as an effective generalized forward controller.
Collapse
Affiliation(s)
- Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy. .,Brain Connectivity Center, C. Mondino National Neurological Institute, Pavia, Italy.
| | - Lisa Mapelli
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.,Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Rome, Italy
| | | | - Jesus A Garrido
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.,Department of Computer Architecture and Technology, University of Granada, Granada, Spain
| | - Niceto Luque
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain
| | - Jessica Monaco
- Brain Connectivity Center, C. Mondino National Neurological Institute, Pavia, Italy
| | - Francesca Prestori
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | | | - Eduardo Ros
- Department of Computer Architecture and Technology, University of Granada, Granada, Spain
| |
Collapse
|
12
|
Delvendahl I, Hallermann S. The Cerebellar Mossy Fiber Synapse as a Model for High-Frequency Transmission in the Mammalian CNS. Trends Neurosci 2016; 39:722-737. [DOI: 10.1016/j.tins.2016.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/17/2016] [Accepted: 09/20/2016] [Indexed: 10/20/2022]
|
13
|
Chronic In Vivo Imaging of Ponto-Cerebellar Mossy Fibers Reveals Morphological Stability during Whisker Sensory Manipulation in the Adult Rat. eNeuro 2015; 2:eN-NWR-0075-15. [PMID: 26693178 PMCID: PMC4676200 DOI: 10.1523/eneuro.0075-15.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/04/2015] [Accepted: 09/28/2015] [Indexed: 11/29/2022] Open
Abstract
The cerebellum receives extensive disynaptic input from the neocortex via the basal pontine nuclei, the neurons of which send mossy fiber (MF) axons to the granule cell layer of the contralateral cerebellar hemisphere. Although this cortico-cerebellar circuit has been implicated in tasks such as sensory discrimination and motor learning, little is known about the potential role of MF morphological plasticity in the function of the cerebellar granule cell layer. To address this issue, we labeled MFs with EGFP via viral infection of the basal pons in adult rats and performed in vivo two-photon imaging of MFs in Crus I/II of the cerebellar hemisphere over a period of several weeks. Following the acquisition of baseline images, animals were housed in control, enriched, or deprived sensory environments. Morphological dynamics were assessed by tracing MF axons and their terminals, and by tracking the stability of filopodia arising from MF terminal rosettes. MF axons and terminals were found to be remarkably stable. Parameters derived neither from measurements of axonal arbor geometry nor from the morphology of individual rosettes and their filopodial extensions significantly changed under control conditions over 4 weeks of imaging. Increasing whisker stimulation by manipulating the sensory environment or decreasing such stimulation by whisker trimming also failed to alter MF structure. Our studies indicate that pontine MF axons projecting to Crus I/II in adult rats do not undergo significant structural rearrangements over the course of weeks, and that this stability is not altered by the sustained manipulation of whisker sensorimotor experience.
Collapse
|
14
|
Long-Term Spatiotemporal Reconfiguration of Neuronal Activity Revealed by Voltage-Sensitive Dye Imaging in the Cerebellar Granular Layer. Neural Plast 2015; 2015:284986. [PMID: 26294979 PMCID: PMC4532947 DOI: 10.1155/2015/284986] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 06/21/2015] [Accepted: 07/01/2015] [Indexed: 11/18/2022] Open
Abstract
Understanding the spatiotemporal organization of long-term synaptic plasticity in neuronal networks demands techniques capable of monitoring changes in synaptic responsiveness over extended multineuronal structures. Among these techniques, voltage-sensitive dye imaging (VSD imaging) is of particular interest due to its good spatial resolution. However, improvements of the technique are needed in order to overcome limits imposed by its low signal-to-noise ratio. Here, we show that VSD imaging can detect long-term potentiation (LTP) and long-term depression (LTD) in acute cerebellar slices. Combined VSD imaging and patch-clamp recordings revealed that the most excited regions were predominantly associated with granule cells (GrCs) generating EPSP-spike complexes, while poorly responding regions were associated with GrCs generating EPSPs only. The correspondence with cellular changes occurring during LTP and LTD was highlighted by a vector representation obtained by combining amplitude with time-to-peak of VSD signals. This showed that LTP occurred in the most excited regions lying in the core of activated areas and increased the number of EPSP-spike complexes, while LTD occurred in the less excited regions lying in the surround. VSD imaging appears to be an efficient tool for investigating how synaptic plasticity contributes to the reorganization of multineuronal activity in neuronal circuits.
Collapse
|
15
|
Mapelli L, Pagani M, Garrido JA, D'Angelo E. Integrated plasticity at inhibitory and excitatory synapses in the cerebellar circuit. Front Cell Neurosci 2015; 9:169. [PMID: 25999817 PMCID: PMC4419603 DOI: 10.3389/fncel.2015.00169] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 04/16/2015] [Indexed: 12/25/2022] Open
Abstract
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.
Collapse
Affiliation(s)
- Lisa Mapelli
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Museo Storico Della Fisica e Centro Studi e Ricerche Enrico Fermi Rome, Italy
| | - Martina Pagani
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Institute of Pharmacology and Toxicology, University of Zurich Zurich, Switzerland
| | - Jesus A Garrido
- Brain Connectivity Center, C. Mondino National Neurological Institute Pavia, Italy ; Department of Computer Architecture and Technology, University of Granada Granada, Spain
| | - Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Brain Connectivity Center, C. Mondino National Neurological Institute Pavia, Italy
| |
Collapse
|
16
|
D'Angelo E. The organization of plasticity in the cerebellar cortex: from synapses to control. PROGRESS IN BRAIN RESEARCH 2014; 210:31-58. [PMID: 24916288 DOI: 10.1016/b978-0-444-63356-9.00002-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The cerebellum is thought to play a critical role in procedural learning, but the relationship between this function and the underlying cellular and synaptic mechanisms remains largely speculative. At present, at least nine forms of long-term synaptic and nonsynaptic plasticity (some of which are bidirectional) have been reported in the cerebellar cortex and deep cerebellar nuclei. These include long-term potentiation (LTP) and long-term depression at the mossy fiber-granule cell synapse, at the synapses formed by parallel fibers, climbing fibers, and molecular layer interneurons on Purkinje cells, and at the synapses formed by mossy fibers and Purkinje cells on deep cerebellar nuclear cells, as well as LTP of intrinsic excitability in granule cells, Purkinje cells, and deep cerebellar nuclear cells. It is suggested that the complex properties of cerebellar learning would emerge from the distribution of plasticity in the network and from its dynamic remodeling during the different phases of learning. Intrinsic and extrinsic factors may hold the key to explain how the different forms of plasticity cooperate to select specific transmission channels and to regulate the signal-to-noise ratio through the cerebellar cortex. These factors include regulation of neuronal excitation by local inhibitory networks, engagement of specific molecular mechanisms by spike bursts and theta-frequency oscillations, and gating by external neuromodulators. Therefore, a new and more complex view of cerebellar plasticity is emerging with respect to that predicted by the original "Motor Learning Theory," opening issues that will require experimental and computational testing.
Collapse
Affiliation(s)
- Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy; Brain Connectivity Center, C. Mondino National Neurological Institute, Pavia, Italy.
| |
Collapse
|
17
|
Cheron G, Dan B, Márquez-Ruiz J. Translational approach to behavioral learning: lessons from cerebellar plasticity. Neural Plast 2013; 2013:853654. [PMID: 24319600 PMCID: PMC3844268 DOI: 10.1155/2013/853654] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 09/18/2013] [Indexed: 11/17/2022] Open
Abstract
The role of cerebellar plasticity has been increasingly recognized in learning. The privileged relationship between the cerebellum and the inferior olive offers an ideal circuit for attempting to integrate the numerous evidences of neuronal plasticity into a translational perspective. The high learning capacity of the Purkinje cells specifically controlled by the climbing fiber represents a major element within the feed-forward and feedback loops of the cerebellar cortex. Reciprocally connected with the basal ganglia and multimodal cerebral domains, this cerebellar network may realize fundamental functions in a wide range of behaviors. This review will outline the current understanding of three main experimental paradigms largely used for revealing cerebellar functions in behavioral learning: (1) the vestibuloocular reflex and smooth pursuit control, (2) the eyeblink conditioning, and (3) the sensory envelope plasticity. For each of these experimental conditions, we have critically revisited the chain of causalities linking together neural circuits, neural signals, and plasticity mechanisms, giving preference to behaving or alert animal physiology. Namely, recent experimental approaches mixing neural units and local field potentials recordings have demonstrated a spike timing dependent plasticity by which the cerebellum remains at a strategic crossroad for deciphering fundamental and translational mechanisms from cellular to network levels.
Collapse
Affiliation(s)
- Guy Cheron
- Laboratory of Electrophysiology, Université de Mons, 7000 Mons, Belgium
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institut, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Bernard Dan
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institut, Université Libre de Bruxelles, 1070 Brussels, Belgium
- Department of Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, 1020 Brussels, Belgium
| | - Javier Márquez-Ruiz
- División de Neurociencias, Universidad Pablo de Olavide, 41013 Sevilla, Spain
| |
Collapse
|
18
|
Garrido JA, Luque NR, D'Angelo E, Ros E. Distributed cerebellar plasticity implements adaptable gain control in a manipulation task: a closed-loop robotic simulation. Front Neural Circuits 2013; 7:159. [PMID: 24130518 PMCID: PMC3793577 DOI: 10.3389/fncir.2013.00159] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 09/17/2013] [Indexed: 01/08/2023] Open
Abstract
Adaptable gain regulation is at the core of the forward controller operation performed by the cerebro-cerebellar loops and it allows the intensity of motor acts to be finely tuned in a predictive manner. In order to learn and store information about body-object dynamics and to generate an internal model of movement, the cerebellum is thought to employ long-term synaptic plasticity. LTD at the PF-PC synapse has classically been assumed to subserve this function (Marr, 1969). However, this plasticity alone cannot account for the broad dynamic ranges and time scales of cerebellar adaptation. We therefore tested the role of plasticity distributed over multiple synaptic sites (Hansel et al., 2001; Gao et al., 2012) by generating an analog cerebellar model embedded into a control loop connected to a robotic simulator. The robot used a three-joint arm and performed repetitive fast manipulations with different masses along an 8-shape trajectory. In accordance with biological evidence, the cerebellum model was endowed with both LTD and LTP at the PF-PC, MF-DCN and PC-DCN synapses. This resulted in a network scheme whose effectiveness was extended considerably compared to one including just PF-PC synaptic plasticity. Indeed, the system including distributed plasticity reliably self-adapted to manipulate different masses and to learn the arm-object dynamics over a time course that included fast learning and consolidation, along the lines of what has been observed in behavioral tests. In particular, PF-PC plasticity operated as a time correlator between the actual input state and the system error, while MF-DCN and PC-DCN plasticity played a key role in generating the gain controller. This model suggests that distributed synaptic plasticity allows generation of the complex learning properties of the cerebellum. The incorporation of further plasticity mechanisms and of spiking signal processing will allow this concept to be extended in a more realistic computational scenario.
Collapse
Affiliation(s)
- Jesús A Garrido
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; A. Volta Physics Department, Consorzio Interuniversitario per le Scienze Fisiche della Materia, University of Pavia Research Unit Pavia, Italy
| | | | | | | |
Collapse
|
19
|
Garrido JA, Ros E, D'Angelo E. Spike timing regulation on the millisecond scale by distributed synaptic plasticity at the cerebellum input stage: a simulation study. Front Comput Neurosci 2013; 7:64. [PMID: 23720626 PMCID: PMC3660969 DOI: 10.3389/fncom.2013.00064] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/02/2013] [Indexed: 11/30/2022] Open
Abstract
The way long-term synaptic plasticity regulates neuronal spike patterns is not completely understood. This issue is especially relevant for the cerebellum, which is endowed with several forms of long-term synaptic plasticity and has been predicted to operate as a timing and a learning machine. Here we have used a computational model to simulate the impact of multiple distributed synaptic weights in the cerebellar granular-layer network. In response to mossy fiber (MF) bursts, synaptic weights at multiple connections played a crucial role to regulate spike number and positioning in granule cells. The weight at MF to granule cell synapses regulated the delay of the first spike and the weight at MF and parallel fiber to Golgi cell synapses regulated the duration of the time-window during which the first-spike could be emitted. Moreover, the weights of synapses controlling Golgi cell activation regulated the intensity of granule cell inhibition and therefore the number of spikes that could be emitted. First-spike timing was regulated with millisecond precision and the number of spikes ranged from zero to three. Interestingly, different combinations of synaptic weights optimized either first-spike timing precision or spike number, efficiently controlling transmission and filtering properties. These results predict that distributed synaptic plasticity regulates the emission of quasi-digital spike patterns on the millisecond time-scale and allows the cerebellar granular layer to flexibly control burst transmission along the MF pathway.
Collapse
Affiliation(s)
- Jesús A Garrido
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Consorzio Interuniversitario per le Scienze Fisiche della Materia Pavia, Italy
| | | | | |
Collapse
|
20
|
Carrillo F, Palomar FJ, Conde V, Diaz-Corrales FJ, Porcacchia P, Fernández-Del-Olmo M, Koch G, Mir P. Study of cerebello-thalamocortical pathway by transcranial magnetic stimulation in Parkinson's disease. Brain Stimul 2013; 6:582-9. [PMID: 23318222 DOI: 10.1016/j.brs.2012.12.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 12/09/2012] [Accepted: 12/11/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Although functional changes in the activation of the cerebellum in Parkinson's disease (PD) patients have been consistently described, it is still debated whether such altered cerebellar activation is a natural consequence of PD pathophysiology or rather it involves compensatory mechanisms. OBJECTIVE/HYPOTHESIS We used different forms of cerebellar transcranial magnetic stimulation to evaluate the hypothesis that altered cerebello-cortical interactions can be observed in PD patients and to evaluate the role of dopaminergic treatment. METHODS We studied the effects of a single cerebellar magnetic pulse over the excitability of the contralateral primary motor cortex tested with motor-evoked potentials (MEPs) (cerebellar-brain inhibition-CBI) in a group of 16 PD patients with (ON) and without dopaminergic treatment (OFF), and in 16 age-matched healthy controls. Moreover, we also tested the effects of cerebellar continuous theta-burst stimulation (cTBS) on MEP amplitude, short intracortical inhibition (SICI) and short intracortical facilitation (SICF) tested in the contralateral M1 in 13 PD patients in ON and OFF and in 16 age-matched healthy controls. RESULTS CBI was evident in controls but not in PD patients, even when tested in both ON and OFF conditions. Similarly, cerebellar cTBS reduced MEP amplitude and SICI in controls but not in PD patients under any condition. CONCLUSION(S) These results demonstrate that PD patients have deficient short-latency and long-lasting cerebellar-thalamocortical inhibitory interactions that cannot be promptly restored by standard dopaminergic medication.
Collapse
Affiliation(s)
- Fátima Carrillo
- Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Contestabile A. Role of nitric oxide in cerebellar development and function: focus on granule neurons. THE CEREBELLUM 2012; 11:50-61. [PMID: 21104176 DOI: 10.1007/s12311-010-0234-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
More than 20 years of research have firmly established important roles of the diffusible messenger molecule, nitric oxide (NO), in cerebellar development and function. Granule neurons are main players in every NO-related mechanism involving cerebellar function and dysfunction. Granule neurons are endowed with remarkable amounts of the Ca(2+)-dependent neuronal isoform of nitric oxide synthase and can directly respond to endogenously produced NO or induce responses in neighboring cells taking advantage of the high diffusibility of the molecule. Nitric oxide acts as a negative regulator of granule cell precursor proliferation and promotes survival and differentiation of these neurons. Nitric oxide is neuroprotective towards granule neurons challenged with toxic insults. Nitric oxide is a main regulator of bidirectional plasticity at parallel fiber-Purkinje neuron synapses, inducing long-term depression (LTD) or long-term potentiation (LTP) depending on postsynaptic Ca(2+) levels, thus playing a central role in cerebellar learning related to motor control. Granule neurons cooperate with glial cells, in particular with microglia, in the regulation of NO production through the respective forms of NOS present in the two cellular types. Aim of the present paper is to review the state of the art and the improvement of our understanding of NO functions in cerebellar granule neurons obtained during the last two decades and to outline possible future development of the research.
Collapse
Affiliation(s)
- Antonio Contestabile
- Department of Biology, University of Bologna, Via Selmi 3, 40126 Bologna, Italy.
| |
Collapse
|
22
|
Modeling spike-train processing in the cerebellum granular layer and changes in plasticity reveal single neuron effects in neural ensembles. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2012; 2012:359529. [PMID: 23193390 PMCID: PMC3463164 DOI: 10.1155/2012/359529] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 07/12/2012] [Indexed: 11/19/2022]
Abstract
The cerebellum input stage has been known to perform combinatorial operations on input signals. In this paper, two types of mathematical models were used to reproduce the role of feed-forward inhibition and computation in the granular layer microcircuitry to investigate spike train processing. A simple spiking model and a biophysically-detailed model of the network were used to study signal recoding in the granular layer and to test observations like center-surround organization and time-window hypothesis in addition to effects of induced plasticity. Simulations suggest that simple neuron models may be used to abstract timing phenomenon in large networks, however detailed models were needed to reconstruct population coding via evoked local field potentials (LFP) and for simulating changes in synaptic plasticity. Our results also indicated that spatio-temporal code of the granular network is mainly controlled by the feed-forward inhibition from the Golgi cell synapses. Spike amplitude and total number of spikes were modulated by LTP and LTD. Reconstructing granular layer evoked-LFP suggests that granular layer propagates the nonlinearities of individual neurons. Simulations indicate that granular layer network operates a robust population code for a wide range of intervals, controlled by the Golgi cell inhibition and is regulated by the post-synaptic excitability.
Collapse
|
23
|
Locatelli F, Bottà L, Prestori F, Masetto S, D'Angelo E. Late-onset bursts evoked by mossy fibre bundle stimulation in unipolar brush cells: evidence for the involvement of H- and TRP-currents. J Physiol 2012; 591:899-918. [PMID: 23129798 DOI: 10.1113/jphysiol.2012.242180] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Synaptic transmission at central synapses has usually short latency and graded amplitude, thereby regulating threshold crossing and the probability of action potential generation. In the granular layer of the vestibulo-cerebellum, unipolar brush cells (UBCs) receive a giant synapse generating a stereotyped excitatory postsynaptic potential (EPSP)-burst complex with early-onset (∼2 ms) and high reliability. By using patch-clamp recordings in cerebellar slices of the rat vestibulo-cerebellum, we found that mossy fibre bundle stimulation also evoked (in ∼80% of cases) a late-onset burst (after tens to hundreds of milliseconds) independent of EPSP generation. Different from the early-onset, the late-onset burst delay decreased and its duration increased by raising stimulation intensity or the number of impulses. Although depending on synaptic activity, the late-onset response was insensitive to perfusion of APV ((2R)-5-amino-phosphonopentanoate), NBQX (2,3-dioxo-6-nitro-tetrahydrobenzo(f)quinoxaline-7-sulfonamide) and MCPG ((RS)-α-methyl-4-carboxyphenylglycine) and did not therefore depend on conventional glutamatergic transmission mechanisms. The late-onset response was initiated by a slow depolarizing ramp driven by activation of an H-current (sensitive to ZD7288 and Cs(+)) and of a TRP- (transient receptor potential) current (sensitive to SKF96365), while the high voltage-activated and high voltage-activated Ca(2+) currents (sensitive to nimodipine and mibefradil, respectively) played a negligible role. The late-onset burst was occluded by intracellular cAMP. These results indicate that afferent activity can regulate H- and TRP-current gating in UBCs generating synaptically driven EPSP-independent responses, in which the delay rather than amplitude is graded with the intensity of the input pattern. This modality of synaptic transmission may play an important role in regulating UBC activation and granular layer functions in the vestibulo-cerebellum.
Collapse
Affiliation(s)
- F Locatelli
- Department of Neuroscience, Via Mondino 2, I-27100 Pavia, Italy
| | | | | | | | | |
Collapse
|
24
|
Brandalise F, Gerber U, Rossi P. Golgi cell-mediated activation of postsynaptic GABA(B) receptors induces disinhibition of the Golgi cell-granule cell synapse in rat cerebellum. PLoS One 2012; 7:e43417. [PMID: 22937048 PMCID: PMC3425594 DOI: 10.1371/journal.pone.0043417] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 07/20/2012] [Indexed: 12/24/2022] Open
Abstract
In the cerebellar glomerulus, GABAergic synapses formed by Golgi cells regulate excitatory transmission from mossy fibers to granule cells through feed-forward and feedback mechanisms. In acute cerebellar slices, we found that stimulating Golgi cell axons with a train of 10 impulses at 100 Hz transiently inhibited both the phasic and the tonic components of inhibitory responses recorded in granule cells. This effect was blocked by the GABAB receptor blocker CGP35348, and could be mimicked by bath-application of baclofen (30 µM). This depression of IPSCs was prevented when granule cells were dialyzed with GDPβS. Furthermore, when synaptic transmission was blocked, GABAA currents induced in granule cells by localized muscimol application were inhibited by the GABAB receptor agonist baclofen. These findings indicate that postsynaptic GABAB receptors are primarily responsible for the depression of IPSCs. This inhibition of inhibitory events results in an unexpected excitatory action by Golgi cells on granule cell targets. The reduction of Golgi cell-mediated inhibition in the cerebellar glomerulus may represent a regulatory mechanism to shift the balance between excitation and inhibition in the glomerulus during cerebellar information processing.
Collapse
Affiliation(s)
- Federico Brandalise
- Dipartimento di Biologia e Biotecnologie “L. Spallanzani”, University of Pavia, Pavia, Italy
- Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Urs Gerber
- Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Paola Rossi
- Dipartimento di Biologia e Biotecnologie “L. Spallanzani”, University of Pavia, Pavia, Italy
- * E-mail:
| |
Collapse
|
25
|
Gao Z, van Beugen BJ, De Zeeuw CI. Distributed synergistic plasticity and cerebellar learning. Nat Rev Neurosci 2012; 13:619-35. [PMID: 22895474 DOI: 10.1038/nrn3312] [Citation(s) in RCA: 353] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Studies on synaptic plasticity in the context of learning have been dominated by the view that a single, particular type of plasticity forms the underlying mechanism for a particular type of learning. However, emerging evidence shows that many forms of synaptic and intrinsic plasticity at different sites are induced conjunctively during procedural memory formation in the cerebellum. Here, we review the main forms of long-term plasticity in the cerebellar cortex that underlie motor learning. We propose that the different forms of plasticity in the granular layer and the molecular layer operate synergistically in a temporally and spatially distributed manner, so as to ultimately create optimal output for behaviour.
Collapse
Affiliation(s)
- Zhenyu Gao
- Department of Neuroscience, Erasmus Medical Center, 3000 DR Rotterdam, The Netherlands
| | | | | |
Collapse
|
26
|
Fenster C, Vullhorst D, Buonanno A. Acute neuregulin-1 signaling influences AMPA receptor mediated responses in cultured cerebellar granule neurons. Brain Res Bull 2012; 87:21-9. [PMID: 22044943 PMCID: PMC3432401 DOI: 10.1016/j.brainresbull.2011.10.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 09/29/2011] [Accepted: 10/20/2011] [Indexed: 12/31/2022]
Abstract
Neuregulin-1 (NRG1) is a trophic and differentiation factor that signals through ErbB receptor tyrosine kinases to regulate nervous system development. Previous studies have demonstrated that NRG1 affects plasticity at glutamatergic synapses in principal glutamatergic neurons of the hippocampus and frontal cortex; however, immunohistochemical and genetic analyses strongly suggest these effects are indirect and mediated via ErbB4 receptors on GABAergic interneurons. Here, we used cultured cerebellar granule cells (CGCs) that express ErbB4 to analyze the cell-autonomous effects of NRG1 stimulation on glutamatergic function. These cultures have the advantage that they are relatively homogenous and consist primarily of granule neurons that express ErbB4. We show that acute NRG1 treatment does not affect whole-cell AMPA or NMDA receptor (NMDAR) mediated currents in CGCs at 10-12 days in vitro. NRG1 also does not affect the frequency or amplitude of spontaneous AMPAR or NMDAR mediated miniature excitatory post-synaptic currents (mEPSCs). To further investigate the effects of NRG1 on activity-dependent plasticity of glutamatergic synapses in CGCs, we characterized the effects of high-glyine/0 Mg(2+) (which activates synaptic NMDARs) on AMPAR-mEPSC frequency and amplitude. We show that high-glycine induces a form of chemical long-term potentiation (chemLTP) in CGCs characterized by an increase in AMPAR-mEPSC frequency but not amplitude. Moreover, NRG1 induces a decrease in AMPAR-mEPSC frequency following chemLTP, but does not affect AMPAR-mEPSC amplitude. CGCs in our cultures conditions express low levels of GluR1, in contrast to dissociated hippocampal cultures, but do express the long isoform of GluR4. This study provides first evidence that (1) high-glycine can induce plasticity at glutamatergic synapses in CGCs, and (2) that acute NRG1/ErbB-signaling can regulate glutamatergic plasticity in CGCs. Taken together with previous reports, our results suggest that, similar to Schaeffer collateral to CA1 synapses, NRG1 effects are activity dependent and mediated via modulation of synaptic AMPARs.
Collapse
Affiliation(s)
- Catherine Fenster
- Department of Biology/Toxicology, 401 College Avenue, Ashland University, Ashland, OH 44805
- Section of Developmental Neurobiology, NICHD, Porter Neuroscience Research Center, Building 35, Room 2C-1002, 35 Convent Drive, Bethesda, MD 20892. 35 Convent Dr Room 2C1000, MSC 3713 Bethesda Md 20892-3713
| | - Detlef Vullhorst
- Section of Developmental Neurobiology, NICHD, Porter Neuroscience Research Center, Building 35, Room 2C-1002, 35 Convent Drive, Bethesda, MD 20892. 35 Convent Dr Room 2C1000, MSC 3713 Bethesda Md 20892-3713
| | - Andres Buonanno
- Section of Developmental Neurobiology, NICHD, Porter Neuroscience Research Center, Building 35, Room 2C-1000, 35 Convent Drive, Bethesda, MD 20892
| |
Collapse
|
27
|
Carey MR. Synaptic mechanisms of sensorimotor learning in the cerebellum. Curr Opin Neurobiol 2011; 21:609-15. [PMID: 21767944 DOI: 10.1016/j.conb.2011.06.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 06/22/2011] [Accepted: 06/23/2011] [Indexed: 01/20/2023]
Abstract
The cerebellum plays an essential role in motor learning. The ability to identify specific sensory and motor signals carried by neurons with known connectivity makes the cerebellum an attractive system for investigating how synaptic plasticity relates to learning. Early studies focused primarily on a single form of plasticity, long-term depression at parallel fiber-Purkinje cell synapses. Recent work has highlighted both the diversity of synaptic plasticity that exists within the cerebellum and the fact that individual plasticity mechanisms can have unexpected consequences when they act within neural circuits.
Collapse
Affiliation(s)
- Megan R Carey
- Neural Circuits and Behavior Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Av. Brasília, Doca de Pedrouços, 1400-038 Lisboa, Portugal.
| |
Collapse
|
28
|
Calcium microdomains near R-type calcium channels control the induction of presynaptic long-term potentiation at parallel fiber to purkinje cell synapses. J Neurosci 2011; 31:5235-43. [PMID: 21471358 DOI: 10.1523/jneurosci.5252-10.2011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
R-type calcium channels in postsynaptic spines signal through functional calcium microdomains to regulate a calcium/calmodulin-sensitive potassium channel that in turn regulates postsynaptic hippocampal long-term potentiation (LTP). Here, we ask whether R-type calcium channels in presynaptic terminals also signal through calcium microdomains to control presynaptic LTP. We focus on presynaptic LTP at parallel fiber to Purkinje cell synapses in the cerebellum (PF-LTP), which is mediated by calcium/calmodulin-stimulated adenylyl cyclases. Although most presynaptic calcium influx is through N-type and P/Q-type calcium channels, blocking these channels does not disrupt PF-LTP, but blocking R-type calcium channels does. Moreover, global calcium signaling cannot account for the calcium dependence of PF-LTP because R-type channels contribute modestly to overall calcium entry. These findings indicate that, within presynaptic terminals, R-type calcium channels produce calcium microdomains that evoke presynaptic LTP at moderate frequencies that do not greatly increase global calcium levels.
Collapse
|
29
|
NR2A subunit of the N-methyl d-aspartate receptors are required for potentiation at the mossy fiber to granule cell synapse and vestibulo-cerebellar motor learning. Neuroscience 2011; 176:274-83. [DOI: 10.1016/j.neuroscience.2010.12.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 12/15/2010] [Accepted: 12/15/2010] [Indexed: 01/28/2023]
|
30
|
Tahon K, Wijnants M, De Schutter E, Maex R. Current source density correlates of cerebellar Golgi and Purkinje cell responses to tactile input. J Neurophysiol 2011; 105:1327-41. [PMID: 21228303 DOI: 10.1152/jn.00317.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The overall circuitry of the cerebellar cortex has been known for over a century, but the function of many synaptic connections remains poorly characterized in vivo. We used a one-dimensional multielectrode probe to estimate the current source density (CSD) of Crus IIa in response to perioral tactile stimuli in anesthetized rats and to correlate current sinks and sources to changes in the spike rate of corecorded Golgi and Purkinje cells. The punctate stimuli evoked two distinct early waves of excitation (at <10 and ∼ 20 ms) associated with current sinks in the granular layer. The second wave was putatively of corticopontine origin, and its associated sink was located higher in the granular layer than the first trigeminal sink. The distinctive patterns of granular-layer sinks correlated with the spike responses of corecorded Golgi cells. In general, Golgi cell spike responses could be linearly reconstructed from the CSD profile. A dip in simple-spike activity of coregistered Purkinje cells correlated with a current source deep in the molecular layer, probably generated by basket cell synapses, interspersed between sparse early sinks presumably generated by synapses from granule cells. The late (>30 ms) enhancement of simple-spike activity in Purkinje cells was characterized by the absence of simultaneous sinks in the granular layer and by the suppression of corecorded Golgi cell activity, pointing at inhibition of Golgi cells by Purkinje axon collaterals as a likely mechanism of late Purkinje cell excitation.
Collapse
Affiliation(s)
- Koen Tahon
- Laboratory for Theoretical Neurobiology, University of Antwerp, Antwerp, Belgium
| | | | | | | |
Collapse
|
31
|
|
32
|
D'Errico A, Prestori F, D'Angelo E. Differential induction of bidirectional long-term changes in neurotransmitter release by frequency-coded patterns at the cerebellar input. J Physiol 2010; 587:5843-57. [PMID: 19858226 DOI: 10.1113/jphysiol.2009.177162] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Sensory stimulation conveys spike discharges of variable frequency and duration along the mossy fibres of cerebellum raising the question of whether and how these patterns determine plastic changes at the mossy fibre-granule cell synapse. Although various combinations of high-frequency bursts and membrane depolarization can induce NMDA receptor-dependent long-term depression (LTD) and long-term potentiation (LTP), the effect of different discharge frequencies remained unknown. Here we show that low-frequency mossy fibre stimulation (100 impulses1 Hz) induces mGlu receptor-dependent LTD. For various burst frequencies, the plasticity-[Ca(2+)](i) relationship was U-shaped resembling the Bienenstok-Cooper-Munro (BCM) learning rule. Moreover, LTD expression was associated with increased paired-pulse ratio, coefficient of variation and failure rate, and with a decrease in release probability, therefore showing changes opposite to those characterizing LTP. The plasticity-[Ca(2+)](i) relationship and the changes in neurotransmitter release measured by varying induction frequencies were indistinguishable from those obtained by varying high-frequency burst duration. These results suggest that different glutamate receptors converge onto a final common mechanism translating the frequency and duration of mossy fibre discharges into a regulation of the LTP/LTD balance, which may play an important role in adapting spatio-temporal signal transformations at the cerebellar input stage.
Collapse
Affiliation(s)
- Anna D'Errico
- Universitá di Pavia, Istituto di Fisiologia Generale, Via Forlanini 6, Pavia I-27100, Italy
| | | | | |
Collapse
|
33
|
Thomsen LB, Jörntell H, Midtgaard J. Presynaptic calcium signalling in cerebellar mossy fibres. Front Neural Circuits 2010; 4:1. [PMID: 20162034 PMCID: PMC2821199 DOI: 10.3389/neuro.04.001.2010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Accepted: 01/04/2010] [Indexed: 11/13/2022] Open
Abstract
Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX)-sensitive fast Na+ spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers. Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none TTX-sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than 1 s affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be modulated locally, suggesting that cerebellar glomeruli may be dynamically sub-compartmentalized due to ongoing inhibition mediated by Golgi cells. This could provide a fine-grained control of mossy fibre-granule cell information transfer and synaptic plasticity within a mossy fibre rosette.
Collapse
Affiliation(s)
- Louiza B Thomsen
- Department of Neuroscience and Pharmacology, University of Copenhagen Copenhagen, Denmark
| | | | | |
Collapse
|
34
|
Courjaret R, Tröger M, Deitmer JW. Suppression of GABA input by A1 adenosine receptor activation in rat cerebellar granule cells. Neuroscience 2009; 162:946-58. [PMID: 19477241 DOI: 10.1016/j.neuroscience.2009.05.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 05/07/2009] [Accepted: 05/21/2009] [Indexed: 12/01/2022]
Abstract
Synaptic transmission has been shown to be modulated by purinergic receptors. In the cerebellum, spontaneous inhibitory input to Purkinje neurons is enhanced by ATP via P2 receptors, while evoked excitatory input via the granule cell parallel fibers is reduced by presynaptic P1 (A1) adenosine receptors. We have now studied the modulation of the complex GABAergic input to granule cells by the purinergic receptor agonists ATP and adenosine in acute rat cerebellar tissue slices using the whole-cell patch-clamp technique. Our experiments indicate that ATP and adenosine substantially reduce the bicuculline- and gabazine-sensitive GABAergic input to granule cells. Both phasic and tonic inhibitory components were reduced leading to an increased excitability of granule cells. The effect of ATP and adenosine could be blocked by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), but not by other P1 and P2 receptor antagonists, indicating that it was mediated by activation of A1 adenosine receptors. Our results suggest that, in the cerebellar network, A1 receptor activation, known to decrease the excitatory output of granule cells, also increases their excitability by reducing their complex GABAergic input. These findings extend our knowledge on purinergic receptors, mediating multiple modulations at both inhibitory and excitatory input and output sites in the cerebellar network.
Collapse
Affiliation(s)
- R Courjaret
- Abteilung für Allgemeine Zoologie, Fachbereich Biologie, Universität Kaiserslautern, Postfach 3049, Erwin-Schrödinger-strasse 13, D-67653, Kaiserslautern, Germany.
| | | | | |
Collapse
|
35
|
Mapelli L, Rossi P, Nieus T, D'Angelo E. Tonic activation of GABAB receptors reduces release probability at inhibitory connections in the cerebellar glomerulus. J Neurophysiol 2009; 101:3089-99. [PMID: 19339456 DOI: 10.1152/jn.91190.2008] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the cerebellum, granule cells are inhibited by Golgi cells through GABAergic synapses generating complex responses involving both phasic neurotransmitter release and the establishment of ambient gamma-aminobutyric acid (GABA) levels. Although at this synapse the mechanisms of postsynaptic integration have been clarified to a considerable extent, the mechanisms of neurotransmitter release remained largely unknown. Here we have investigated the quantal properties of release during repetitive neurotransmission, revealing that tonic GABA(B) receptor activation by ambient GABA regulates release probability. Blocking GABA(B) receptors with CGP55845 enhanced the first inhibitory postsynaptic current (IPSC) and short-term depression in a train while reducing trial-to-trial variability and failures. The changes caused by CGP55845 were similar to those caused by increasing extracellular Ca(2+) concentration, in agreement with a presynaptic GABA(B) receptor modulation of release probability. However, the slow tail following IPSC peak demonstrated a remarkable temporal summation and was not modified by CGP55845 or extracellular Ca(2+) increase. This result shows that tonic activation of presynaptic GABA(B) receptors by ambient GABA selectively regulates the onset of inhibition bearing potential consequences for the dynamic regulation of signal transmission through the mossy fiber-granule cell pathway of the cerebellum.
Collapse
Affiliation(s)
- Lisa Mapelli
- Department of Physiological and Pharmacological Sciences and National Consortium for the Physics of Matter, University of Pavia, I-27100 Pavia, Italy
| | | | | | | |
Collapse
|
36
|
D'Angelo E, Koekkoek SKE, Lombardo P, Solinas S, Ros E, Garrido J, Schonewille M, De Zeeuw CI. Timing in the cerebellum: oscillations and resonance in the granular layer. Neuroscience 2009; 162:805-15. [PMID: 19409229 DOI: 10.1016/j.neuroscience.2009.01.048] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 01/21/2009] [Accepted: 01/24/2009] [Indexed: 11/16/2022]
Abstract
The brain generates many rhythmic activities, and the olivo-cerebellar system is not an exception. In recent years, the cerebellum has revealed activities ranging from low frequency to very high-frequency oscillations. These rhythms depend on the brain functional state and are typical of certain circuit sections or specific neurons. Interestingly, the granular layer, which gates sensorimotor and cognitive signals to the cerebellar cortex, can also sustain low frequency (7-25 Hz) and perhaps higher-frequency oscillations. In this review we have considered (i) how these oscillations are generated in the granular layer network depending on intrinsic electroresponsiveness and circuit connections, (ii) how these oscillations are correlated with those in other cerebellar circuit sections, and (iii) how the oscillating cerebellum communicates with extracerebellar structures. It is suggested that the granular layer can generate oscillations that integrate well with those generated in the inferior olive, in deep-cerebellar nuclei and in Purkinje cells. These rhythms, in turn, might play a role in cognition and memory consolidation by interacting with the mechanisms of long-term synaptic plasticity.
Collapse
Affiliation(s)
- E D'Angelo
- Department of Physiology, University of Pavia, CNISM (Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia), Via Forlanini 6, I-27100, Pavia, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
37
|
D'Angelo E, De Zeeuw CI. Timing and plasticity in the cerebellum: focus on the granular layer. Trends Neurosci 2008; 32:30-40. [PMID: 18977038 DOI: 10.1016/j.tins.2008.09.007] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2008] [Revised: 09/12/2008] [Accepted: 09/15/2008] [Indexed: 02/02/2023]
Abstract
Two of the most striking properties of the cerebellum are its control in timing of motor operations and its ability to adapt behavior to new sensorimotor associations. Here, we propose a 'time-window matching' hypothesis for granular layer processing. Our hypothesis states that mossy fiber inputs to the granular layer are transformed into well-timed spike bursts by intrinsic granule cell processing, that feedforward Golgi cell inhibition sets a limit to the duration of such bursts and that these activities are spread over particular fields in the granular layer so as to generate ongoing time-windows for proper control of interacting motor domains. The role of synaptic plasticity would be that of fine-tuning pre-wired circuits favoring activation of specific granule cell groups in relation to particular time windows. This concept has wide implications for processing in the olivo-cerebellar system as a whole.
Collapse
Affiliation(s)
- Egidio D'Angelo
- Department of Cellular and Molecular Physiological and Pharmacological Sciences, University of Pavia and CNISM, Via Forlanini 6, I-27100 Pavia, Italy.
| | | |
Collapse
|
38
|
Koch G, Mori F, Marconi B, Codecà C, Pecchioli C, Salerno S, Torriero S, Lo Gerfo E, Mir P, Oliveri M, Caltagirone C. Changes in intracortical circuits of the human motor cortex following theta burst stimulation of the lateral cerebellum. Clin Neurophysiol 2008; 119:2559-69. [PMID: 18824403 DOI: 10.1016/j.clinph.2008.08.008] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 08/09/2008] [Accepted: 08/18/2008] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The cerebellum takes part in several motor functions through its influence on the motor cortex (M1). Here, we applied the theta burst stimulation (TBS) protocol, a novel form of repetitive Transcranial Magnetic Stimulation (rTMS) over the lateral cerebellum. The aim of this study was to test whether TBS of the lateral cerebellum could be able to modulate the excitability of the contralateral M1 in healthy subjects. METHODS Motor-evoked potentials (MEPs) amplitude, short intracortical inhibition (SICI), long intracortical inhibition (LICI) and short intracortical facilitation (SICF) were tested in the M1 before and after cerebellar continuous TBS (cTBS) or intermittent TBS (iTBS). RESULTS We found that cTBS induced a reduction of SICI and an increase of LICI. On the other hand, cerebellar iTBS reduced LICI. MEPs amplitude also differently vary following cerebellar stimulation with cTBS or iTBS, resulting in a decrease by the former and an increase by the latter. CONCLUSIONS Although the interpretation of these data remains highly speculative, these findings reveal that the cerebellar cortex undergoes bidirectional plastic changes that modulate different intracortical circuits within the contralateral primary motor cortex. SIGNIFICANCE Long-lasting modifications of these pathways could be useful to treat various pathological conditions characterized by an altered cortical excitability.
Collapse
Affiliation(s)
- Giacomo Koch
- Laboratorio di Neurologia Clinica e Comportamentale, Fondazione Santa Lucia IRCCS, Via Ardeatina, 306, 00179 Rome, Italy.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Tactile stimulation evokes long-term synaptic plasticity in the granular layer of cerebellum. J Neurosci 2008; 28:6354-9. [PMID: 18562605 DOI: 10.1523/jneurosci.5709-07.2008] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Several forms of long-term synaptic plasticity [long-term potentiation (LTP) and long-term depression (LTD)] have been reported in the cerebellar circuit in vitro, but their determination in vivo was still lacking in most cases. Here we show that, in the urethane-anesthetized rat, appropriate patterns of facial tactile stimulation as well as intracerebellar electrical stimulation can induce LTP and LTD in local field potentials recorded from the granular layer of Crus-IIa. LTD prevailed in control conditions, whereas LTP prevailed during local application of gabazine. No relevant plasticity was observed when gabazine and APV were coapplied. The pharmacological and kinetic properties of LTP and LTD in vivo were compatible with those reported in the granule cell layer in vitro (Mapelli and D'Angelo, 2007), suggesting that NMDA receptor-dependent plasticity was generated at the mossy fiber-granule cell synapse under the inhibitory control of the Golgi cell circuit. Interestingly, LTP and LTD were able to regulate the response latency to tactile stimulation, as expected from computational modeling of the expression mechanisms (Nieus et al., 2006). This result suggests that LTP and LTD could regulate the spatiotemporal pattern of granular layer responses to mossy fiber inputs.
Collapse
|
40
|
D'Angelo E. The critical role of Golgi cells in regulating spatio-temporal integration and plasticity at the cerebellum input stage. Front Neurosci 2008; 2:35-46. [PMID: 18982105 PMCID: PMC2570065 DOI: 10.3389/neuro.01.008.2008] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Accepted: 06/12/2008] [Indexed: 11/28/2022] Open
Abstract
The discovery of the Golgi cell is bound to the foundation of the Neuron Doctrine. Recently, the excitable mechanisms of this inhibitory interneuron have been investigated with modern experimental and computational techniques raising renewed interest for the implications it might have for cerebellar circuit functions. Golgi cells are pacemakers with preferential response frequency and phase-reset in the theta-frequency band and can therefore impose specific temporal dynamics to granule cell responses. Moreover, through their connectivity, Golgi cells determine the spatio-temporal organization of cerebellar activity. Finally, Golgi cells, by controlling granule cell depolarization and NMDA channel unblock, regulate the induction of long-term synaptic plasticity at the mossy fiber – granule cell synapse. Thus, the Golgi cells can exert an extensive control on spatio-temporal signal organization and information storage in the granular layer playing a critical role for cerebellar computation.
Collapse
Affiliation(s)
- Egidio D'Angelo
- Department of Cellular and Molecular Physiological and Pharmacological Sciences, University of Pavia and CNISM Pavia, Italy.
| |
Collapse
|
41
|
Abstract
A major goal of learning and memory research is to correlate the function of molecules with the behaviour of organisms. The beautiful laminar structure of the cerebellar cortex lends itself to the study of synaptic plasticity, because its clearly defined patterns of neurons and their synapses form circuits that have been implicated in simple motor behaviour paradigms. The best understood in terms of molecular mechanism is the parallel fibre-Purkinje cell synapse, where presynaptic long-term potentiation and postsynaptic long-term depression and potentiation finely tune cerebellar output. Our understanding of these forms of plasticity has mostly come from the electrophysiological and behavioural analysis of knockout mutant mice, but more recently the knock-in of synaptic molecules with mutated phosphorylation sites and binding domains has provided more detailed insights into the signalling events. The present review details the major forms of plasticity in the cerebellar cortex, with particular attention to the membrane trafficking and intracellular signalling responsible. This overview of the current literature suggests it will not be long before the involvement of the cerebellum in certain motor behaviours is fully explained in molecular terms.
Collapse
Affiliation(s)
- Gareth J O Evans
- Department of Biology (Area 3), University of York, Heslington, York, UK.
| |
Collapse
|
42
|
Mapelli J, D'Angelo E. The spatial organization of long-term synaptic plasticity at the input stage of cerebellum. J Neurosci 2007; 27:1285-96. [PMID: 17287503 PMCID: PMC6673576 DOI: 10.1523/jneurosci.4873-06.2007] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 12/09/2006] [Accepted: 12/23/2006] [Indexed: 11/21/2022] Open
Abstract
The spatial organization of long-term synaptic plasticity [long-term potentiation (LTP) and long-term depression (LTD)] is supposed to play a critical role for distributed signal processing in neuronal networks, but its nature remains undetermined in most central circuits. By using multielectrode array recordings, we have reconstructed activation maps of the granular layer in cerebellar slices. LTP and LTD induced by theta-burst stimulation appeared in patches organized in such a way that, on average, LTP was surrounded by LTD. The sign of long-term synaptic plasticity in a given granular layer region was directly correlated with excitation and inversely correlated with inhibition: the most active areas tended to generate LTP, whereas the least active areas tended to generate LTD. Plasticity was almost entirely prevented by application of the NMDA receptor blocker, APV. This suggests that synaptic inhibition, through a control of membrane depolarization, effectively regulates NMDA channel unblock, postsynaptic calcium entry, and the induction of bidirectional synaptic plasticity at the mossy fiber-granule cell relay (Gall et al., 2005). By this mechanism, LTP and LTD could regulate the geometry and contrast of network computations, preprocessing the mossy fiber input to be conveyed to Purkinje cells and molecular layer interneurons.
Collapse
Affiliation(s)
- Jonathan Mapelli
- Department of Cellular and Molecular Physiological and Pharmacological Sciences, University of Pavia and National Institute for the Physics of Matter, I-27100 Pavia, Italy
| | - Egidio D'Angelo
- Department of Cellular and Molecular Physiological and Pharmacological Sciences, University of Pavia and National Institute for the Physics of Matter, I-27100 Pavia, Italy
| |
Collapse
|
43
|
Torres JB, Assunção J, Farias JA, Kahwage R, Lins N, Passos A, Quintairos A, Trévia N, Diniz CWP. NADPH-diaphorase histochemical changes in the hippocampus, cerebellum and striatum are correlated with different modalities of exercise and watermaze performances. Exp Brain Res 2006; 175:292-304. [PMID: 16763833 DOI: 10.1007/s00221-006-0549-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2006] [Accepted: 05/05/2006] [Indexed: 02/08/2023]
Abstract
Nitric oxide is involved in memory and motor learning. We investigated possible influences of exercise on spatial memory and NADPH-diaphorase (NADPH-d) histochemical activity in the hippocampus, striatum and cerebellum. Fifteen albino Swiss mice between the 22nd and 55th post-natal days were exercised in the following modalities: voluntary (V), acrobatic (A), acrobatic/voluntary (AV) and forced (F) and compared to inactive group (I). After the exercise period, all subjects were tested in the water maze for 3 days. Animal brains were processed for NADPH-d histochemistry. Densitometry of the neuropil of the hippocampus, striatum and cerebellum and morphometric analysis of NADPHd+ type I neurons of the striatum were done. Exercise groups presented higher levels of NADPH-d activity in the molecular and polymorphic layers of dentate gyrus and lacunosum molecular layer of CA1. The A group presented higher NADPH-d activity in the cerebellar granular layer than all other groups. Branching points and dendritic segment densities of NADPH-d type I neurons were higher in V, A and AV than in F and I groups. Exercise groups revealed best performances on water maze tests. Thus, different modalities of exercise increases in different proportions for the nitrergic activity in the hippocampus, striatum and cerebellum, and these changes seem to be beneficial to spatial memory.
Collapse
|
44
|
Gall D, Prestori F, Sola E, D'Errico A, Roussel C, Forti L, Rossi P, D'Angelo E. Intracellular calcium regulation by burst discharge determines bidirectional long-term synaptic plasticity at the cerebellum input stage. J Neurosci 2006; 25:4813-22. [PMID: 15888657 PMCID: PMC6724778 DOI: 10.1523/jneurosci.0410-05.2005] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Variations in intracellular calcium concentration ([Ca2+]i) provide a critical signal for synaptic plasticity. In accordance with Hebb's postulate (Hebb, 1949), an increase in postsynaptic [Ca2+]i can induce bidirectional changes in synaptic strength depending on activation of specific biochemical pathways (Bienenstock et al., 1982; Lisman, 1989; Stanton and Sejnowski, 1989). Despite its strategic location for signal processing, spatiotemporal dynamics of [Ca2+]i changes and their relationship with synaptic plasticity at the cerebellar mossy fiber (mf)-granule cell (GrC) relay were unknown. In this paper, we report the plasticity/[Ca2+]i relationship for GrCs, which are typically activated by mf bursts (Chadderton et al., 2004). Mf bursts caused a remarkable [Ca2+]i increase in GrC dendritic terminals through the activation of NMDA receptors, metabotropic glutamate receptors (probably acting through IP3-sensitive stores), voltage-dependent calcium channels, and Ca2+-induced Ca2+ release. Although [Ca2+]i increased with the duration of mf bursts, long-term depression was found with a small [Ca2+]i increase (bursts <250 ms), and long-term potentiation (LTP) was found with a large [Ca2+]i increase (bursts >250 ms). LTP and [Ca2+]i saturated for bursts >500 ms and with theta-burst stimulation. Thus, bursting enabled a Ca2+-dependent bidirectional Bienenstock-Cooper-Munro-like learning mechanism providing the cellular basis for effective learning of burst patterns at the input stage of the cerebellum.
Collapse
Affiliation(s)
- David Gall
- Department of Cellular-Molecular Physiological and Pharmacological Sciences, University of Pavia, I-27100 Pavia, Italy
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Evans GJO, Morgan A. Phosphorylation of cysteine string protein in the brain: developmental, regional and synaptic specificity. Eur J Neurosci 2005; 21:2671-80. [PMID: 15926915 DOI: 10.1111/j.1460-9568.2005.04118.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Protein phosphorylation modulates regulated exocytosis in most cells, including neurons. Cysteine string protein (CSP) has been implicated in this process because its phosphorylation on Ser10 alters its interactions with syntaxin and synaptotagmin, and because the effect of CSP overexpression on exocytosis kinetics in chromaffin cells requires phosphorylatable Ser10. To characterize CSP phosphorylation in the brain, we raised phosphospecific antibodies to Ser10. Western blotting revealed that the proportion of phosphorylated CSP (P-CSP) varies between distinct brain regions and also exhibits developmental regulation, with P-CSP highest early in development. Immunohistochemical analysis of the cerebellar cortex revealed a novel pool of P-CSP that did not colocalize with synaptic vesicle markers during early development. Strikingly, in the adult cerebellar granular layer P-CSP was highly enriched in a subset of glutamatergic synapses but undetectable in neighbouring GABA-ergic synapses. In view of the functional consequences of CSP phosphorylation, such differences could contribute to the synapse-specific regulation of neurotransmitter release.
Collapse
Affiliation(s)
- Gareth J O Evans
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | | |
Collapse
|
46
|
D'Angelo E, Rossi P, Gall D, Prestori F, Nieus T, Maffei A, Sola E. Long-term potentiation of synaptic transmission at the mossy fiber-granule cell relay of cerebellum. PROGRESS IN BRAIN RESEARCH 2005; 148:69-80. [PMID: 15661182 DOI: 10.1016/s0079-6123(04)48007-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the last decade, the physiology of cerebellar neurons and synapses has been extended to a considerable extent. We have found that the mossy fiber-granule cell relay can generate a complex form of long-term potentiation (mf-GrC LTP) following high-frequency mf discharge. Induction. Mf-GrC LTP depends on NMDA and mGlu receptor activation, intracellular Ca(2+) increase, PKC activation, and NO production. The preventative action of intracellular agents (BAPTA, PKC-inhibitors) and of membrane hyperpolarization, and the correlated increase in intracellular Ca(2+) observed using fluorescent dyes, indicate that induction occurs postsynaptically. Expression. Expression includes three components: (a) an increase of synaptic currents, (b) an increase of intrinsic excitability in GrC, and (c) an increase of intrinsic excitability in mf terminals. Based on quantal analysis, the EPSC increase is mostly explained by enhanced neurotransmitter release. NO is a candidate retrograde neurotransmitter which could determine both presynaptic current changes and LTP. NO cascade blockers inhibit both presynaptic current changes and LTP. The increase in intrinsic excitability involves a raise in apparent input resistance in the subthreshold region and a spike threshold reduction. Together with other forms of cerebellar plasticity, mf-GrC LTP opens new hypothesis on how the cerebellum processes incoming information.
Collapse
Affiliation(s)
- Egidio D'Angelo
- Department of Cellular and Molecular Physiology and Pharmacology, University Pavia and INFM, Via Forlanini 6, I-27100 Pavia, Italy.
| | | | | | | | | | | | | |
Collapse
|
47
|
Kloepfer JA, Cohen N, Nadeau JL. FRET between CdSe Quantum Dots in Lipid Vesicles and Water- and Lipid-soluble Dyes. J Phys Chem B 2004. [DOI: 10.1021/jp048094c] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeremiah A. Kloepfer
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, and School of Computing, University of Leeds, Leeds LS2 9JT, U.K
| | - Netta Cohen
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, and School of Computing, University of Leeds, Leeds LS2 9JT, U.K
| | - Jay L. Nadeau
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, and School of Computing, University of Leeds, Leeds LS2 9JT, U.K
| |
Collapse
|
48
|
Ozaki M, Itoh K, Miyakawa Y, Kishida H, Hashikawa T. Protein processing and releases of neuregulin-1 are regulated in an activity-dependent manner. J Neurochem 2004; 91:176-88. [PMID: 15379898 DOI: 10.1111/j.1471-4159.2004.02719.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Identification of the key molecules that bridge presynaptic neuronal events and long-term modification of the postsynaptic process is an important challenge which will have to be met in order to further our understanding of the mechanisms for learning and memory. This study is focused on neuregulin-1 (NRG-1), a neurotrophic factor, that is known to regulate the development of various tissues and/or the life/death of cells through activation of the ErbB family receptor tyrosine kinases. It was discovered that the soluble form of NRG-1 (sNRG-1) is produced from the transmembrane form of NRG through proteolytic cleavage during electrical stimulation of either cultured cerebellar granule cells (GCs) or pontine nucleus neurons (PNs) that are presynaptic to GCs. sNRG-1 was assayed by measuring the phosphorylation of both the ErbB receptors and cyclic AMP-responsive element-binding protein (CREB), and by means of antibodies to sNRG-1. The cleavage and release of NRG-1 depended on the frequency of electrical stimulation; the peak effect was at 50 Hz in both GCs and PNs. Activation of protein kinase C (PKC) mimicked this effect. The culture apparatus provided along with the mass-electrical stimulation that was employed proved to be a powerful tool for combining neuronal electrical events and chemical events. We conclude from the results that, in mossy fibre (PN axon)-GC synapses, electrical activity controls the proteolytic processing of NRG-1 in a frequency-dependent fashion and involves PKC. Furthermore, cleaved sNRG-1 plays an important functional role in regulating transmission across these synapses.
Collapse
Affiliation(s)
- Miwako Ozaki
- Laboratory for Memory and Learning, Brain Science Institute, RIKEN (The Institute of Physical and Chemical Research), Saitama, Japan.
| | | | | | | | | |
Collapse
|
49
|
Sola E, Prestori F, Rossi P, Taglietti V, D'Angelo E. Increased neurotransmitter release during long-term potentiation at mossy fibre-granule cell synapses in rat cerebellum. J Physiol 2004; 557:843-61. [PMID: 15090602 PMCID: PMC1665150 DOI: 10.1113/jphysiol.2003.060285] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2003] [Accepted: 04/16/2004] [Indexed: 11/08/2022] Open
Abstract
During long-term potentiation (LTP) at mossy fibre-granule cell synapses in rat cerebellum synaptic transmission and granule cell intrinsic excitability are enhanced. Although it is clear that changes in granule cell excitability are mediated postsynaptically, there is as yet no direct evidence for the site and mechanism of changes in transmission. To approach this problem, evoked postsynaptic currents (EPSCs) and miniature synaptic currents (mEPSCs) were recorded by patch-clamp in cerebellar slices obtained from P17-P23 rats. LTP was induced by theta-burst stimulation paired with depolarization. During LTP, the EPSCs showed a significant decrease in the coefficient of variation (CV; 28.9 +/- 5.2%, n= 8; P < 0.002), the number of failures (87.1 +/- 41.9%, n= 8; P < 0.04), and the paired-pulse ratio (PPR; 25.5 +/- 4.1% n= 5; P < 0.02). Similar changes were observed by increasing neurotransmitter release (extracellular solutions with high Ca(2+)/Mg(2+) ratio), whereas increases in CV, numbers of failures and PPR occurred when release was decreased (extracellular solutions with low Ca(2+)/Mg(2+) ratio; 10 microm Cl-adenosine). No changes followed modifications of postsynaptic holding potentials, while CV and failures were reduced when the number of active synapses was increased. LTP was prevented by use of solutions with high Ca(2+)/Mg(2+) ratio. Moreover, LTP and the associated CV decrease were observed in the spillover-mediated component of AMPA EPSCs and in NMDA EPSCs. During LTP, mEPSCs did not change in amplitude or variability but significantly increased in frequency (47.6 +/- 16%, n= 4; P < 0.03). By binomial analysis changes in EPSCs were shown to be due to increased release probability (from 0.6 +/- 0.08 to 0.73 +/- 0.06, n= 7; P < 0.02) with a constant number of three to four releasing sites. These observations provide evidence for increased neurotransmitter release during LTP at mossy fibre-granule cell synapses.
Collapse
Affiliation(s)
- Elisabetta Sola
- Department of Physiology and Pharmacological Sciences, University of Pavia, Via Forlanini 6, 27100 Pavia, I-27100, Italy
| | | | | | | | | |
Collapse
|
50
|
Maffei A, Prestori F, Shibuki K, Rossi P, Taglietti V, D'Angelo E. NO enhances presynaptic currents during cerebellar mossy fiber-granule cell LTP. J Neurophysiol 2004; 90:2478-83. [PMID: 14534272 DOI: 10.1152/jn.00399.2003] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitric oxide (NO) is a candidate retrograde messenger in long-term potentiation (LTP). The NO metabolic pathway is expressed in the cerebellar granule cell layer but its physiological role remained unknown. In this paper we have investigated the role of NO in cerebellar mossy fiber-granule cell LTP, which has postsynaptic N-methyl-d-aspartate (NMDA) receptor-dependent induction. Pre- and postsynaptic current changes were simultaneously measured by using extracellular focal recordings, and NO release was monitored with an electrochemical probe in P21 rat cerebellar slices. High-frequency mossy fiber stimulation induced LTP and caused a significant NO release (6.2 +/- 2.8 nM; n = 5) in the granular layer that was dependent on NMDA receptor as well as on nitric oxide synthase (NOS) activation. Preventing NO production by perfusing the NOS inhibitor 100 microM NG-nitro-l-arginine (L-NNA), blocking extracellular NO diffusion by 10 microM MbO2, or inhibiting the NO target guanylyl cyclase (sGC) with 10 microM 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-dione (ODQ) prevented LTP. Moreover, the NO donor 10 microM 2-(N,N-diethylamino)-diazenolate-2-oxide.Na (DEA-NO) induced LTP, which was mutually occlusive with LTP generated by high-frequency stimulation, prevented by ODQ, and insensitive to NMDA channel blockade (50 microM APV + 25 microM 7-Cl-kyn) or interruption of mossy fiber stimulation. Thus NO is critical for LTP induction at the cerebellar mossy fiber-granule cell relay. Interestingly, LTP manipulations were accompanied by consensual changes in the presynaptic current, suggesting that NO acts as a retrograde signal-enhancing presynaptic terminal excitability.
Collapse
Affiliation(s)
- Arianna Maffei
- Department of Physiology and Pharmacology, Pavia University, 27100, Pavia, Italy
| | | | | | | | | | | |
Collapse
|