1
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Brown ST, Medina-Pizarro M, Holla M, Vaaga CE, Raman IM. Simple spike patterns and synaptic mechanisms encoding sensory and motor signals in Purkinje cells and the cerebellar nuclei. Neuron 2024; 112:1848-1861.e4. [PMID: 38492575 PMCID: PMC11156563 DOI: 10.1016/j.neuron.2024.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 01/04/2024] [Accepted: 02/15/2024] [Indexed: 03/18/2024]
Abstract
Whisker stimulation in awake mice evokes transient suppression of simple spike probability in crus I/II Purkinje cells. Here, we investigated how simple spike suppression arises synaptically, what it encodes, and how it affects cerebellar output. In vitro, monosynaptic parallel fiber (PF)-excitatory postsynaptic currents (EPSCs) facilitated strongly, whereas disynaptic inhibitory postsynaptic currents (IPSCs) remained stable, maximizing relative inhibitory strength at the onset of PF activity. Short-term plasticity thus favors the inhibition of Purkinje spikes before PFs facilitate. In vivo, whisker stimulation evoked a 2-6 ms synchronous spike suppression, just 6-8 ms (∼4 synaptic delays) after sensory onset, whereas active whisker movements elicited broadly timed spike rate increases that did not modulate sensory-evoked suppression. Firing in the cerebellar nuclei (CbN) inversely correlated with disinhibition from sensory-evoked simple spike suppressions but was decoupled from slow, non-synchronous movement-associated elevations of Purkinje firing rates. Synchrony thus allows the CbN to high-pass filter Purkinje inputs, facilitating sensory-evoked cerebellar outputs that can drive movements.
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Affiliation(s)
- Spencer T Brown
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Mauricio Medina-Pizarro
- Department of Neurobiology, Northwestern University, Evanston, IL, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA
| | - Meghana Holla
- Department of Neurobiology, Northwestern University, Evanston, IL, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA
| | | | - Indira M Raman
- Department of Neurobiology, Northwestern University, Evanston, IL, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA.
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2
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Nomura T. In Vitro Patch-Clamp. Methods Mol Biol 2024; 2794:221-244. [PMID: 38630233 DOI: 10.1007/978-1-0716-3810-1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
The patch-clamp technique is one of the most useful tools to analyze the function of electrically active cells such as neurons. This technique allows for the analysis of proteins (ion channels and receptors), cells (neurons), and synapses that are the building blocks of neuronal networks. Cortical development involves coordinated changes in functional measures at each of these levels of analysis that reflect both cellular and circuit maturation. This chapter explains the technical and theoretical basis of patch-clamp methodology and introduces several examples of how this technique can be applied in the context of cortical development.
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Affiliation(s)
- Toshihiro Nomura
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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3
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Chao OY, Pathak SS, Zhang H, Augustine GJ, Christie JM, Kikuchi C, Taniguchi H, Yang YM. Social memory deficit caused by dysregulation of the cerebellar vermis. Nat Commun 2023; 14:6007. [PMID: 37752149 PMCID: PMC10522595 DOI: 10.1038/s41467-023-41744-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 09/15/2023] [Indexed: 09/28/2023] Open
Abstract
Social recognition memory (SRM) is a key determinant of social interactions. While the cerebellum emerges as an important region for social behavior, how cerebellar activity affects social functions remains unclear. We selectively increased the excitability of molecular layer interneurons (MLIs) to suppress Purkinje cell firing in the mouse cerebellar vermis. Chemogenetic perturbation of MLIs impaired SRM without affecting sociability, anxiety levels, motor coordination or object recognition. Optogenetic interference of MLIs during distinct phases of a social recognition test revealed the cerebellar engagement in the retrieval, but not encoding, of social information. c-Fos mapping after the social recognition test showed that cerebellar manipulation decreased brain-wide interregional correlations and altered network structure from medial prefrontal cortex and hippocampus-centered to amygdala-centered modules. Anatomical tracing demonstrated hierarchical projections from the central cerebellum to the social brain network integrating amygdalar connections. Our findings suggest that the cerebellum organizes the neural matrix necessary for SRM.
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Affiliation(s)
- Owen Y Chao
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, 55812, USA
| | - Salil Saurav Pathak
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, 55812, USA
| | - Hao Zhang
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, 55812, USA
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, 308232, Singapore, Singapore
| | - Jason M Christie
- University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Chikako Kikuchi
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Hiroki Taniguchi
- Department of Pathology, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
- Chronic Brain Injury, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Yi-Mei Yang
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, 55812, USA.
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.
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4
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Binda F, Spaeth L, Kumar A, Isope P. Excitation and Inhibition Delays within a Feedforward Inhibitory Pathway Modulate Cerebellar Purkinje Cell Output in Mice. J Neurosci 2023; 43:5905-5917. [PMID: 37495382 PMCID: PMC10436687 DOI: 10.1523/jneurosci.0091-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 06/30/2023] [Accepted: 07/18/2023] [Indexed: 07/28/2023] Open
Abstract
The cerebellar cortex computes sensorimotor information from many brain areas through a feedforward inhibitory (FFI) microcircuit between the input stage, the granule cell (GC) layer, and the output stage, the Purkinje cells (PCs). Although in other brain areas FFI underlies a precise excitation versus inhibition temporal correlation, recent findings in the cerebellum highlighted more complex behaviors at GC-molecular layer interneuron (MLI)-PC pathway. To dissect the temporal organization of this cerebellar FFI pathway, we combined ex vivo patch-clamp recordings of PCs in male mice with a viral-based strategy to express Channelrhodopsin2 in a subset of mossy fibers (MFs), the major excitatory inputs to GCs. We show that although light-mediated MF activation elicited pairs of excitatory and inhibitory postsynaptic currents in PCs, excitation (E) from GCs and inhibition (I) from MLIs reached PCs with a wide range of different temporal delays. However, when GCs were directly stimulated, a low variability in E/I delays was observed. Our results demonstrate that in many recordings MF stimulation recruited different groups of GCs that trigger E and/or I, and expanded PC temporal synaptic integration. Finally, using a computational model of the FFI pathway, we showed that this temporal expansion could strongly influence how PCs integrate GC inputs. Our findings show that specific E/I delays may help PCs encoding specific MF inputs.SIGNIFICANCE STATEMENT Sensorimotor information is conveyed to the cerebellar cortex by mossy fibers. Mossy fiber inputs activate granule cells that excite molecular interneurons and Purkinje cells, the sole output of the cerebellar cortex, leading to a sequence of synaptic excitation and inhibition in Purkinje cells, thus defining a feedforward inhibitory pathway. Using electrophysiological recordings, optogenetic stimulation, and mathematical modeling, we demonstrated that different groups of granule cells can elicit synaptic excitation and inhibition with various latencies onto Purkinje cells. This temporal variability controls how granule cells influence Purkinje cell discharge and may support temporal coding in the cerebellar cortex.
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Affiliation(s)
- Francesca Binda
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
| | - Ludovic Spaeth
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
| | - Arvind Kumar
- Division of Computational Science and Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Philippe Isope
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg, France
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5
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Martin HGS, Kullmann DM. Basket to Purkinje Cell Inhibitory Ephaptic Coupling Is Abolished in Episodic Ataxia Type 1. Cells 2023; 12:1382. [PMID: 37408217 PMCID: PMC10216961 DOI: 10.3390/cells12101382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/07/2023] [Accepted: 05/08/2023] [Indexed: 07/07/2023] Open
Abstract
Dominantly inherited missense mutations of the KCNA1 gene, which encodes the KV1.1 potassium channel subunit, cause Episodic Ataxia type 1 (EA1). Although the cerebellar incoordination is thought to arise from abnormal Purkinje cell output, the underlying functional deficit remains unclear. Here we examine synaptic and non-synaptic inhibition of Purkinje cells by cerebellar basket cells in an adult mouse model of EA1. The synaptic function of basket cell terminals was unaffected, despite their intense enrichment for KV1.1-containing channels. In turn, the phase response curve quantifying the influence of basket cell input on Purkine cell output was maintained. However, ultra-fast non-synaptic ephaptic coupling, which occurs in the cerebellar 'pinceau' formation surrounding the axon initial segment of Purkinje cells, was profoundly reduced in EA1 mice in comparison with their wild type littermates. The altered temporal profile of basket cell inhibition of Purkinje cells underlines the importance of Kv1.1 channels for this form of signalling, and may contribute to the clinical phenotype of EA1.
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Affiliation(s)
| | - Dimitri M. Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK;
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6
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Chin PW, Augustine GJ. The cerebellum and anxiety. Front Cell Neurosci 2023; 17:1130505. [PMID: 36909285 PMCID: PMC9992220 DOI: 10.3389/fncel.2023.1130505] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 01/24/2023] [Indexed: 02/24/2023] Open
Abstract
Although the cerebellum is traditionally known for its role in motor functions, recent evidence points toward the additional involvement of the cerebellum in an array of non-motor functions. One such non-motor function is anxiety behavior: a series of recent studies now implicate the cerebellum in anxiety. Here, we review evidence regarding the possible role of the cerebellum in anxiety-ranging from clinical studies to experimental manipulation of neural activity-that collectively points toward a role for the cerebellum, and possibly a specific topographical locus within the cerebellum, as one of the orchestrators of anxiety responses.
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Affiliation(s)
- Pei Wern Chin
- Program in Neuroscience & Mental Health, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - George J Augustine
- Program in Neuroscience & Mental Health, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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7
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Kassa M, Bradley J, Jalil A, Llano I. KCa1.1 channels contribute to optogenetically driven post-stimulation silencing in cerebellar molecular layer interneurons. J Gen Physiol 2022; 155:213661. [PMID: 36326690 PMCID: PMC9640226 DOI: 10.1085/jgp.202113004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 07/06/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022] Open
Abstract
Using cell-attached recordings from molecular layer interneurons (MLI) of the cerebellar cortex of adult mice expressing channel rhodopsin 2, we show that wide-field optical activation induces an increase in firing rate during illumination and a firing pause when the illumination ends (post-stimulation silencing; PSS). Significant spike rate changes with respect to basal firing rate were observed for optical activations lasting 200 ms and 1 s as well as for 1 s long trains of 10 ms pulses at 50 Hz. For all conditions, the net effect of optical activation on the integrated spike rate is significantly reduced because of PSS. Three lines of evidence indicate that this PSS is due to intrinsic factors. Firstly, PSS is induced when the optical stimulation is restricted to a single MLI using a 405-nm laser delivering a diffraction-limited spot at the focal plane. Secondly, PSS is not affected by block of GABA-A or GABA-B receptors, ruling out synaptic interactions amongst MLIs. Thirdly, PSS is mimicked in whole-cell recording experiments by step depolarizations under current clamp. Activation of Ca-dependent K channels during the spike trains appears as a likely candidate to underlie PSS. Using immunocytochemistry, we find that one such channel type, KCa1.1, is present in the somato-dendritic and axonal compartments of MLIs. In cell-attached recordings, charybdotoxin and iberiotoxin significantly reduce the optically induced PSS, while TRAM-34 does not affect it, suggesting that KCa1.1 channels, but not KCa3.1 channels, contribute to PSS.
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Affiliation(s)
- Merouann Kassa
- Université Paris Cité, Centre National de la Recherche Scientifique, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Jonathan Bradley
- Institut de Biologie de l’Ecole Normale Superieure (IBENS), Ecole Normale Superieure, Centre National de la Recherche Scientifique, INSERM, Paris Sciences et Lettres Research University, Paris, France
| | - Abdelali Jalil
- Université Paris Cité, Centre National de la Recherche Scientifique, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Isabel Llano
- Université Paris Cité, Centre National de la Recherche Scientifique, Saints-Pères Paris Institute for the Neurosciences, Paris, France
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8
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Masoli S, Rizza MF, Tognolina M, Prestori F, D’Angelo E. Computational models of neurotransmission at cerebellar synapses unveil the impact on network computation. Front Comput Neurosci 2022; 16:1006989. [PMID: 36387305 PMCID: PMC9649760 DOI: 10.3389/fncom.2022.1006989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/10/2022] [Indexed: 11/25/2022] Open
Abstract
The neuroscientific field benefits from the conjoint evolution of experimental and computational techniques, allowing for the reconstruction and simulation of complex models of neurons and synapses. Chemical synapses are characterized by presynaptic vesicle cycling, neurotransmitter diffusion, and postsynaptic receptor activation, which eventually lead to postsynaptic currents and subsequent membrane potential changes. These mechanisms have been accurately modeled for different synapses and receptor types (AMPA, NMDA, and GABA) of the cerebellar cortical network, allowing simulation of their impact on computation. Of special relevance is short-term synaptic plasticity, which generates spatiotemporal filtering in local microcircuits and controls burst transmission and information flow through the network. Here, we present how data-driven computational models recapitulate the properties of neurotransmission at cerebellar synapses. The simulation of microcircuit models is starting to reveal how diverse synaptic mechanisms shape the spatiotemporal profiles of circuit activity and computation.
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Affiliation(s)
- Stefano Masoli
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | | | | | - Francesca Prestori
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- *Correspondence: Francesca Prestori,
| | - Egidio D’Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- IRCCS Mondino Foundation, Brain Connectivity Center, Pavia, Italy
- Egidio D’Angelo,
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9
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Morphological pseudotime ordering and fate mapping reveal diversification of cerebellar inhibitory interneurons. Nat Commun 2022; 13:3433. [PMID: 35701402 PMCID: PMC9197879 DOI: 10.1038/s41467-022-30977-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 05/20/2022] [Indexed: 12/15/2022] Open
Abstract
Understanding how diverse neurons are assembled into circuits requires a framework for describing cell types and their developmental trajectories. Here we combine genetic fate-mapping, pseudotemporal profiling of morphogenesis, and dual morphology and RNA labeling to resolve the diversification of mouse cerebellar inhibitory interneurons. Molecular layer interneurons (MLIs) derive from a common progenitor population but comprise diverse dendritic-, somatic-, and axon initial segment-targeting interneurons. Using quantitative morphology from 79 mature MLIs, we identify two discrete morphological types and presence of extensive within-class heterogeneity. Pseudotime trajectory inference using 732 developmental morphologies indicate the emergence of distinct MLI types during migration, before reaching their final positions. By comparing MLI identities from morphological and transcriptomic signatures, we demonstrate the dissociation between these modalities and that subtype divergence can be resolved from axonal morphogenesis prior to marker gene expression. Our study illustrates the utility of applying single-cell methods to quantify morphology for defining neuronal diversification.
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10
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Gaffield MA, Sauerbrei BA, Christie JM. Cerebellum encodes and influences the initiation, performance, and termination of discontinuous movements in mice. eLife 2022; 11:71464. [PMID: 35451957 PMCID: PMC9075950 DOI: 10.7554/elife.71464] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 04/21/2022] [Indexed: 11/23/2022] Open
Abstract
The cerebellum is hypothesized to represent timing information important for organizing salient motor events during periodically performed discontinuous movements. To provide functional evidence validating this idea, we measured and manipulated Purkinje cell (PC) activity in the lateral cerebellum of mice trained to volitionally perform periodic bouts of licking for regularly allocated water rewards. Overall, PC simple spiking modulated during task performance, mapping phasic tongue protrusions and retractions, as well as ramping prior to both lick-bout initiation and termination, two important motor events delimiting movement cycles. The ramping onset occurred earlier for the initiation of uncued exploratory licking that anticipated water availability relative to licking that was reactive to water allocation, suggesting that the cerebellum is engaged differently depending on the movement context. In a subpopulation of PCs, climbing-fiber-evoked responses also increased during lick-bout initiation, but not termination, highlighting differences in how cerebellar input pathways represent task-related information. Optogenetic perturbation of PC activity disrupted the behavior by degrading lick-bout rhythmicity in addition to initiating and terminating licking bouts confirming a causative role in movement organization. Together, these results substantiate that the cerebellum contributes to the initiation and timing of repeated motor actions.
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Affiliation(s)
| | - Britton A Sauerbrei
- School of Medicine, Case Western Reserve University, Cleveland, United States
| | - Jason M Christie
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, United States
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11
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Halverson HE, Kim J, Khilkevich A, Mauk MD, Augustine GJ. Feedback inhibition underlies new computational functions of cerebellar interneurons. eLife 2022; 11:77603. [PMID: 36480240 PMCID: PMC9771357 DOI: 10.7554/elife.77603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
The function of a feedback inhibitory circuit between cerebellar Purkinje cells and molecular layer interneurons (MLIs) was defined by combining optogenetics, neuronal activity recordings both in cerebellar slices and in vivo, and computational modeling. Purkinje cells inhibit a subset of MLIs in the inner third of the molecular layer. This inhibition is non-reciprocal, short-range (less than 200 μm) and is based on convergence of one to two Purkinje cells onto MLIs. During learning-related eyelid movements in vivo, the activity of a subset of MLIs progressively increases as Purkinje cell activity decreases, with Purkinje cells usually leading the MLIs. Computer simulations indicate that these relationships are best explained by the feedback circuit from Purkinje cells to MLIs and that this feedback circuit plays a central role in making cerebellar learning efficient.
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Affiliation(s)
- Hunter E Halverson
- Center for Learning and Memory, The University of TexasAustinUnited States
| | - Jinsook Kim
- Program in Neuroscience & Mental Health, Lee Kong Chian School of Medicine, Nanyang Technological UniversitySingaporeSingapore,Institute of Molecular and Cell BiologySingaporeSingapore
| | - Andrei Khilkevich
- Center for Learning and Memory, The University of TexasAustinUnited States
| | - Michael D Mauk
- Center for Learning and Memory, The University of TexasAustinUnited States,Department of Neuroscience, The University of TexasAustinUnited States
| | - George J Augustine
- Program in Neuroscience & Mental Health, Lee Kong Chian School of Medicine, Nanyang Technological UniversitySingaporeSingapore,Institute of Molecular and Cell BiologySingaporeSingapore
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12
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Biane C, Rückerl F, Abrahamsson T, Saint-Cloment C, Mariani J, Shigemoto R, DiGregorio DA, Sherrard RM, Cathala L. Developmental emergence of two-stage nonlinear synaptic integration in cerebellar interneurons. eLife 2021; 10:65954. [PMID: 34730085 PMCID: PMC8565927 DOI: 10.7554/elife.65954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
Synaptic transmission, connectivity, and dendritic morphology mature in parallel during brain development and are often disrupted in neurodevelopmental disorders. Yet how these changes influence the neuronal computations necessary for normal brain function are not well understood. To identify cellular mechanisms underlying the maturation of synaptic integration in interneurons, we combined patch-clamp recordings of excitatory inputs in mouse cerebellar stellate cells (SCs), three-dimensional reconstruction of SC morphology with excitatory synapse location, and biophysical modeling. We found that postnatal maturation of postsynaptic strength was homogeneously reduced along the somatodendritic axis, but dendritic integration was always sublinear. However, dendritic branching increased without changes in synapse density, leading to a substantial gain in distal inputs. Thus, changes in synapse distribution, rather than dendrite cable properties, are the dominant mechanism underlying the maturation of neuronal computation. These mechanisms favor the emergence of a spatially compartmentalized two-stage integration model promoting location-dependent integration within dendritic subunits.
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Affiliation(s)
- Celia Biane
- Sorbonne Université et CNRS UMR 8256, Adaptation Biologique et Vieillissement, Paris, France
| | - Florian Rückerl
- Institut Pasteur, Université de Paris, CNRS UMR 3571, Unit of Synapse and Circuit Dynamics, Paris, France
| | - Therese Abrahamsson
- Institut Pasteur, Université de Paris, CNRS UMR 3571, Unit of Synapse and Circuit Dynamics, Paris, France
| | - Cécile Saint-Cloment
- Institut Pasteur, Université de Paris, CNRS UMR 3571, Unit of Synapse and Circuit Dynamics, Paris, France
| | - Jean Mariani
- Sorbonne Université et CNRS UMR 8256, Adaptation Biologique et Vieillissement, Paris, France
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - David A DiGregorio
- Institut Pasteur, Université de Paris, CNRS UMR 3571, Unit of Synapse and Circuit Dynamics, Paris, France
| | - Rachel M Sherrard
- Sorbonne Université et CNRS UMR 8256, Adaptation Biologique et Vieillissement, Paris, France
| | - Laurence Cathala
- Sorbonne Université et CNRS UMR 8256, Adaptation Biologique et Vieillissement, Paris, France.,Paris Brain Institute, CNRS UMR 7225 - Inserm U1127 - Sorbonne Université Groupe Hospitalier Pitié Salpêtrière, Paris, France
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13
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Kim J, Augustine GJ. Molecular Layer Interneurons: Key Elements of Cerebellar Network Computation and Behavior. Neuroscience 2020; 462:22-35. [PMID: 33075461 DOI: 10.1016/j.neuroscience.2020.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 02/05/2023]
Abstract
Molecular layer interneurons (MLIs) play an important role in cerebellar information processing by controlling Purkinje cell (PC) activity via inhibitory synaptic transmission. A local MLI network, constructed from both chemical and electrical synapses, is organized into spatially structured clusters that amplify feedforward and lateral inhibition to shape the temporal and spatial patterns of PC activity. Several recent in vivo studies indicate that such MLI circuits contribute not only to sensorimotor information processing, but also to precise motor coordination and cognitive processes. Here, we review current understanding of the organization of MLI circuits and their roles in the function of the mammalian cerebellum.
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Affiliation(s)
- Jinsook Kim
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore 308238, Singapore
| | - George J Augustine
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore 308238, Singapore.
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14
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Hoehne A, McFadden MH, DiGregorio DA. Feed-forward recruitment of electrical synapses enhances synchronous spiking in the mouse cerebellar cortex. eLife 2020; 9:57344. [PMID: 32990593 PMCID: PMC7524550 DOI: 10.7554/elife.57344] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 09/09/2020] [Indexed: 01/21/2023] Open
Abstract
In the cerebellar cortex, molecular layer interneurons use chemical and electrical synapses to form subnetworks that fine-tune the spiking output of the cerebellum. Although electrical synapses can entrain activity within neuronal assemblies, their role in feed-forward circuits is less well explored. By combining whole-cell patch-clamp and 2-photon laser scanning microscopy of basket cells (BCs), we found that classical excitatory postsynaptic currents (EPSCs) are followed by GABAA receptor-independent outward currents, reflecting the hyperpolarization component of spikelets (a synapse-evoked action potential passively propagating from electrically coupled neighbors). FF recruitment of the spikelet-mediated inhibition curtails the integration time window of concomitant excitatory postsynaptic potentials (EPSPs) and dampens their temporal integration. In contrast with GABAergic-mediated feed-forward inhibition, the depolarizing component of spikelets transiently increases the peak amplitude of EPSPs, and thus postsynaptic spiking probability. Therefore, spikelet transmission can propagate within the BC network to generate synchronous inhibition of Purkinje cells, which can entrain cerebellar output for driving temporally precise behaviors.
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Affiliation(s)
- Andreas Hoehne
- Laboratory of Synapse and Circuit Dynamics, Institut Pasteur, Paris Cedex, France.,Sorbonne University, ED3C, Paris, France
| | - Maureen H McFadden
- Laboratory of Synapse and Circuit Dynamics, Institut Pasteur, Paris Cedex, France
| | - David A DiGregorio
- Laboratory of Synapse and Circuit Dynamics, Institut Pasteur, Paris Cedex, France
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15
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Nagaeva E, Zubarev I, Bengtsson Gonzales C, Forss M, Nikouei K, de Miguel E, Elsilä L, Linden AM, Hjerling-Leffler J, Augustine GJ, Korpi ER. Heterogeneous somatostatin-expressing neuron population in mouse ventral tegmental area. eLife 2020; 9:59328. [PMID: 32749220 PMCID: PMC7440918 DOI: 10.7554/elife.59328] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/01/2020] [Indexed: 12/17/2022] Open
Abstract
The cellular architecture of the ventral tegmental area (VTA), the main hub of the brain reward system, remains only partially characterized. To extend the characterization to inhibitory neurons, we have identified three distinct subtypes of somatostatin (Sst)-expressing neurons in the mouse VTA. These neurons differ in their electrophysiological and morphological properties, anatomical localization, as well as mRNA expression profiles. Importantly, similar to cortical Sst-containing interneurons, most VTA Sst neurons express GABAergic inhibitory markers, but some of them also express glutamatergic excitatory markers and a subpopulation even express dopaminergic markers. Furthermore, only some of the proposed marker genes for cortical Sst neurons were expressed in the VTA Sst neurons. Physiologically, one of the VTA Sst neuron subtypes locally inhibited neighboring dopamine neurons. Overall, our results demonstrate the remarkable complexity and heterogeneity of VTA Sst neurons and suggest that these cells are multifunctional players in the midbrain reward circuitry.
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Affiliation(s)
- Elina Nagaeva
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ivan Zubarev
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | | | - Mikko Forss
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kasra Nikouei
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Elena de Miguel
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Lauri Elsilä
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anni-Maija Linden
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jens Hjerling-Leffler
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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16
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Nagaeva E, Zubarev I, Bengtsson Gonzales C, Forss M, Nikouei K, de Miguel E, Elsilä L, Linden AM, Hjerling-Leffler J, Augustine GJ, Korpi ER. Heterogeneous somatostatin-expressing neuron population in mouse ventral tegmental area. eLife 2020. [PMID: 32749220 DOI: 10.1038/gene] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The cellular architecture of the ventral tegmental area (VTA), the main hub of the brain reward system, remains only partially characterized. To extend the characterization to inhibitory neurons, we have identified three distinct subtypes of somatostatin (Sst)-expressing neurons in the mouse VTA. These neurons differ in their electrophysiological and morphological properties, anatomical localization, as well as mRNA expression profiles. Importantly, similar to cortical Sst-containing interneurons, most VTA Sst neurons express GABAergic inhibitory markers, but some of them also express glutamatergic excitatory markers and a subpopulation even express dopaminergic markers. Furthermore, only some of the proposed marker genes for cortical Sst neurons were expressed in the VTA Sst neurons. Physiologically, one of the VTA Sst neuron subtypes locally inhibited neighboring dopamine neurons. Overall, our results demonstrate the remarkable complexity and heterogeneity of VTA Sst neurons and suggest that these cells are multifunctional players in the midbrain reward circuitry.
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Affiliation(s)
- Elina Nagaeva
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ivan Zubarev
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | | | - Mikko Forss
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kasra Nikouei
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Elena de Miguel
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Lauri Elsilä
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anni-Maija Linden
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jens Hjerling-Leffler
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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17
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Yamaura H, Igarashi J, Yamazaki T. Simulation of a Human-Scale Cerebellar Network Model on the K Computer. Front Neuroinform 2020; 14:16. [PMID: 32317955 PMCID: PMC7146068 DOI: 10.3389/fninf.2020.00016] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 03/18/2020] [Indexed: 12/15/2022] Open
Abstract
Computer simulation of the human brain at an individual neuron resolution is an ultimate goal of computational neuroscience. The Japanese flagship supercomputer, K, provides unprecedented computational capability toward this goal. The cerebellum contains 80% of the neurons in the whole brain. Therefore, computer simulation of the human-scale cerebellum will be a challenge for modern supercomputers. In this study, we built a human-scale spiking network model of the cerebellum, composed of 68 billion spiking neurons, on the K computer. As a benchmark, we performed a computer simulation of a cerebellum-dependent eye movement task known as the optokinetic response. We succeeded in reproducing plausible neuronal activity patterns that are observed experimentally in animals. The model was built on dedicated neural network simulation software called MONET (Millefeuille-like Organization NEural neTwork), which calculates layered sheet types of neural networks with parallelization by tile partitioning. To examine the scalability of the MONET simulator, we repeatedly performed simulations while changing the number of compute nodes from 1,024 to 82,944 and measured the computational time. We observed a good weak-scaling property for our cerebellar network model. Using all 82,944 nodes, we succeeded in simulating a human-scale cerebellum for the first time, although the simulation was 578 times slower than the wall clock time. These results suggest that the K computer is already capable of creating a simulation of a human-scale cerebellar model with the aid of the MONET simulator.
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Affiliation(s)
- Hiroshi Yamaura
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | - Jun Igarashi
- Head Office for Information Systems and Cybersecurity, RIKEN, Saitama, Japan
| | - Tadashi Yamazaki
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
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18
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Park H, Kim T, Kim J, Yamamoto Y, Tanaka-Yamamoto K. Inputs from Sequentially Developed Parallel Fibers Are Required for Cerebellar Organization. Cell Rep 2019; 28:2939-2954.e5. [DOI: 10.1016/j.celrep.2019.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 06/10/2019] [Accepted: 07/30/2019] [Indexed: 11/15/2022] Open
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19
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Dopamine D2 receptor-mediated circuit from the central amygdala to the bed nucleus of the stria terminalis regulates impulsive behavior. Proc Natl Acad Sci U S A 2018; 115:E10730-E10739. [PMID: 30348762 PMCID: PMC6233075 DOI: 10.1073/pnas.1811664115] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Impulsivity is closely associated with addictive disorders, and changes in the brain dopamine system have been proposed to affect impulse control in reward-related behaviors. However, the central neural pathways through which the dopamine system controls impulsive behavior are still unclear. We found that the absence of the D2 dopamine receptor (D2R) increased impulsive behavior in mice, whereas restoration of D2R expression specifically in the central amygdala (CeA) of D2R knockout mice (Drd2 -/- ) normalized their enhanced impulsivity. Inhibitory synaptic output from D2R-expressing neurons in the CeA underlies modulation of impulsive behavior because optogenetic activation of D2R-positive inhibitory neurons that project from the CeA to the bed nucleus of the stria terminalis (BNST) attenuate such behavior. Our identification of the key contribution of D2R-expressing neurons in the CeA → BNST circuit to the control of impulsive behavior reveals a pathway that could serve as a target for approaches to the management of neuropsychiatric disorders associated with impulsivity.
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20
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Gaffield MA, Rowan MJM, Amat SB, Hirai H, Christie JM. Inhibition gates supralinear Ca 2+ signaling in Purkinje cell dendrites during practiced movements. eLife 2018; 7:36246. [PMID: 30117806 PMCID: PMC6120752 DOI: 10.7554/elife.36246] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 08/16/2018] [Indexed: 11/25/2022] Open
Abstract
Motor learning involves neural circuit modifications in the cerebellar cortex, likely through re-weighting of parallel fiber inputs onto Purkinje cells (PCs). Climbing fibers instruct these synaptic modifications when they excite PCs in conjunction with parallel fiber activity, a pairing that enhances climbing fiber-evoked Ca2+ signaling in PC dendrites. In vivo, climbing fibers spike continuously, including during movements when parallel fibers are simultaneously conveying sensorimotor information to PCs. Whether parallel fiber activity enhances climbing fiber Ca2+ signaling during motor behaviors is unknown. In mice, we found that inhibitory molecular layer interneurons (MLIs), activated by parallel fibers during practiced movements, suppressed parallel fiber enhancement of climbing fiber Ca2+ signaling in PCs. Similar results were obtained in acute slices for brief parallel fiber stimuli. Interestingly, more prolonged parallel fiber excitation revealed latent supralinear Ca2+ signaling. Therefore, the balance of parallel fiber and MLI input onto PCs regulates concomitant climbing fiber Ca2+ signaling.
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Affiliation(s)
| | - Matthew J M Rowan
- Max Planck Florida Institute for Neuroscience, Jupiter, United States
| | - Samantha B Amat
- Max Planck Florida Institute for Neuroscience, Jupiter, United States
| | - Hirokazu Hirai
- Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Jason M Christie
- Max Planck Florida Institute for Neuroscience, Jupiter, United States
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21
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Graded Control of Climbing-Fiber-Mediated Plasticity and Learning by Inhibition in the Cerebellum. Neuron 2018; 99:999-1015.e6. [PMID: 30122378 DOI: 10.1016/j.neuron.2018.07.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 06/06/2018] [Accepted: 07/17/2018] [Indexed: 11/22/2022]
Abstract
Purkinje cell dendrites convert excitatory climbing fiber input into signals that instruct plasticity and motor learning. Modulation of instructive signaling may increase the range in which learning is encoded, yet the mechanisms that allow for this are poorly understood. We found that optogenetic activation of molecular layer interneurons (MLIs) that inhibit Purkinje cells suppressed climbing-fiber-evoked dendritic Ca2+ spiking. Inhibitory suppression of Ca2+ spiking depended on the level of MLI activation and influenced the induction of associative synaptic plasticity, converting climbing-fiber-mediated potentiation of parallel fiber-evoked responses into depression. In awake mice, optogenetic activation of floccular climbing fibers in association with head rotation produced an adaptive increase in the vestibulo-ocular reflex (VOR). However, when climbing fibers were co-activated with MLIs, adaptation occurred in the opposite direction, decreasing the VOR. Thus, MLIs can direct a continuous spectrum of plasticity and learning through their influence on Purkinje cell dendritic Ca2+ signaling.
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22
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Tantra M, Guo L, Kim J, Zainolabidin N, Eulenburg V, Augustine GJ, Chen AI. Conditional deletion of Cadherin 13 perturbs Golgi cells and disrupts social and cognitive behaviors. GENES, BRAIN, AND BEHAVIOR 2018; 17:e12466. [PMID: 29446202 PMCID: PMC6635760 DOI: 10.1111/gbb.12466] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 02/02/2018] [Accepted: 02/05/2018] [Indexed: 12/21/2022]
Abstract
Inhibitory interneurons mediate the gating of synaptic transmission and modulate the activities of neural circuits. Disruption of the function of inhibitory networks in the forebrain is linked to impairment of social and cognitive behaviors, but the involvement of inhibitory interneurons in the cerebellum has not been assessed. We found that Cadherin 13 (Cdh13), a gene implicated in autism spectrum disorder and attention-deficit hyperactivity disorder, is specifically expressed in Golgi cells within the cerebellar cortex. To assess the function of Cdh13 and utilize the manipulation of Cdh13 expression in Golgi cells as an entry point to examine cerebellar-mediated function, we generated mice carrying Cdh13-floxed alleles and conditionally deleted Cdh13 with GlyT2::Cre mice. Loss of Cdh13 results in a decrease in the expression/localization of GAD67 and reduces spontaneous inhibitory postsynaptic current (IPSC) in cerebellar Golgi cells without disrupting spontaneous excitatory postsynaptic current (EPSC). At the behavioral level, loss of Cdh13 in the cerebellum, piriform cortex and endopiriform claustrum have no impact on gross motor coordination or general locomotor behaviors, but leads to deficits in cognitive and social abilities. Mice lacking Cdh13 exhibit reduced cognitive flexibility and loss of preference for contact region concomitant with increased reciprocal social interactions. Together, our findings show that Cdh13 is critical for inhibitory function of Golgi cells, and that GlyT2::Cre-mediated deletion of Cdh13 in non-executive centers of the brain, such as the cerebellum, may contribute to cognitive and social behavioral deficits linked to neurological disorders.
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Affiliation(s)
- M. Tantra
- School of Biological SciencesNanyang Technological University (NTU)Singapore
- School of Life SciencesUniversity of WarwickCoventryUK
| | - L. Guo
- School of Biological SciencesNanyang Technological University (NTU)Singapore
- School of Life SciencesUniversity of WarwickCoventryUK
| | - J. Kim
- Lee Kong Chian School of MedicineNanyang Technological University (NTU)Singapore
| | - N. Zainolabidin
- School of Biological SciencesNanyang Technological University (NTU)Singapore
- School of Life SciencesUniversity of WarwickCoventryUK
| | - V. Eulenburg
- Institute of BiochemistryFriedrich‐Alexander University Erlangen‐NurembergErlangenGermany
| | - G. J. Augustine
- Lee Kong Chian School of MedicineNanyang Technological University (NTU)Singapore
- Institute of Molecular and Cell BiologySingapore
| | - A. I. Chen
- School of Biological SciencesNanyang Technological University (NTU)Singapore
- School of Life SciencesUniversity of WarwickCoventryUK
- Institute of Molecular and Cell BiologySingapore
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23
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Alcami P. Electrical Synapses Enhance and Accelerate Interneuron Recruitment in Response to Coincident and Sequential Excitation. Front Cell Neurosci 2018; 12:156. [PMID: 29973871 PMCID: PMC6020792 DOI: 10.3389/fncel.2018.00156] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 05/17/2018] [Indexed: 01/17/2023] Open
Abstract
Electrical synapses are ubiquitous in interneuron networks. They form intercellular pathways, allowing electrical currents to leak between coupled interneurons. I explored the impact of electrical coupling on the integration of excitatory signals and on the coincidence detection abilities of electrically-coupled cerebellar basket cells (BCs). In order to do so, I quantified the influence of electrical coupling on the rate, the probability and the latency at which BCs generate action potentials when stimulated. The long-lasting simultaneous suprathreshold depolarization of a coupled cell evoked an increase in firing rate and a shortening of action potential latency in a reference basket cell, compared to its depolarization alone. Likewise, the action potential probability of coupled cells was strongly increased when they were simultaneously stimulated with trains of short-duration near-threshold current pulses (mimicking the activation of presynaptic granule cells) at 10 Hz, and to a lesser extent at 50 Hz, an effect that was absent in non-coupled cells. Moreover, action potential probability was increased and action potential latency was shortened in response to synaptic stimulations in mice lacking the protein that forms gap junctions between BCs, connexin36, relative to wild-type (WT) controls. These results suggest that electrical synapses between BCs decrease the probability and increase the latency of stimulus-triggered action potentials, both effects being reverted upon simultaneous excitation of coupled cells. Interestingly, varying the delay at which coupled cells are stimulated revealed that the probability and the speed of action potential generation are facilitated maximally when a basket cell is stimulated shortly after a coupled cell. These findings suggest that electrically-coupled interneurons behave as coincidence and sequence detectors that dynamically regulate the latency and the strength of inhibition onto postsynaptic targets depending on the degree of input synchrony in the coupled interneuron network.
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Affiliation(s)
- Pepe Alcami
- Laboratoire de Physiologie Cérébrale, Unité Mixte de Recherche UMR8118, Université Paris Descartes and Centre National de la Recherche Scientifique, Paris, France.,Laboratory of Cellular and Systemic Neurophysiology, Institute for Physiology I, Albert-Ludwigs University Freiburg, Freiburg, Germany.,Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA, United States.,Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany
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24
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Edamakanti CR, Do J, Didonna A, Martina M, Opal P. Mutant ataxin1 disrupts cerebellar development in spinocerebellar ataxia type 1. J Clin Invest 2018. [PMID: 29533923 DOI: 10.1172/jci96765] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Spinocerebellar ataxia type 1 (SCA1) is an adult-onset neurodegenerative disease caused by a polyglutamine expansion in the protein ATXN1, which is involved in transcriptional regulation. Although symptoms appear relatively late in life, primarily from cerebellar dysfunction, pathogenesis begins early, with transcriptional changes detectable as early as a week after birth in SCA1-knockin mice. Given the importance of this postnatal period for cerebellar development, we asked whether this region might be developmentally altered by mutant ATXN1. We found that expanded ATXN1 stimulates the proliferation of postnatal cerebellar stem cells in SCA1 mice. These hyperproliferating stem cells tended to differentiate into GABAergic inhibitory interneurons rather than astrocytes; this significantly increased the GABAergic inhibitory interneuron synaptic connections, disrupting cerebellar Purkinje cell function in a non-cell autonomous manner. We confirmed the increased basket cell-Purkinje cell connectivity in human SCA1 patients. Mutant ATXN1 thus alters the neural circuitry of the developing cerebellum, setting the stage for the later vulnerability of Purkinje cells to SCA1. We propose that other late-onset degenerative diseases may also be rooted in subtle developmental derailments.
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Affiliation(s)
| | - Jeehaeh Do
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | | | - Marco Martina
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Puneet Opal
- Davee Department of Neurology, and.,Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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25
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Optical interrogation of neuronal circuitry in zebrafish using genetically encoded voltage indicators. Sci Rep 2018; 8:6048. [PMID: 29662090 PMCID: PMC5902623 DOI: 10.1038/s41598-018-23906-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 03/20/2018] [Indexed: 11/21/2022] Open
Abstract
Optical measurement of membrane potentials enables fast, direct and simultaneous detection of membrane potentials from a population of neurons, providing a desirable approach for functional analysis of neuronal circuits. Here, we applied recently developed genetically encoded voltage indicators, ASAP1 (Accelerated Sensor of Action Potentials 1) and QuasAr2 (Quality superior to Arch 2), to zebrafish, an ideal model system for studying neurogenesis. To achieve this, we established transgenic lines which express the voltage sensors, and showed that ASAP1 is expressed in zebrafish neurons. To examine whether neuronal activity could be detected by ASAP1, we performed whole-cerebellum imaging, showing that depolarization was detected widely in the cerebellum and optic tectum upon electrical stimulation. Spontaneous activity in the spinal cord was also detected by ASAP1 imaging at single-cell resolution as well as at the neuronal population level. These responses mostly disappeared following treatment with tetrodotoxin, indicating that ASAP1 enabled optical measurement of neuronal activity in the zebrafish brain. Combining this method with other approaches, such as optogenetics and behavioural analysis may facilitate a deeper understanding of the functional organization of brain circuitry and its development.
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26
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Robinson JC, Chapman CA, Courtemanche R. Gap Junction Modulation of Low-Frequency Oscillations in the Cerebellar Granule Cell Layer. THE CEREBELLUM 2018; 16:802-811. [PMID: 28421552 DOI: 10.1007/s12311-017-0858-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Local field potential (LFP) oscillations in the granule cell layer (GCL) of the cerebellar cortex have been identified previously in the awake rat and monkey during immobility. These low-frequency oscillations are thought to be generated through local circuit interactions between Golgi cells and granule cells within the GCL. Golgi cells display rhythmic firing and pacemaking properties, and also are electrically coupled through gap junctions within the GCL. Here, we tested if gap junctions in the rat cerebellar cortex contribute to the generation of LFP oscillations in the GCL. We recorded LFP oscillations under urethane anesthesia, and examined the effects of local infusion of gap junction blockers on 5-15 Hz oscillations. Local infusion of the gap junction blockers carbenoxolone and mefloquine resulted in significant decreases in the power of oscillations over a 30-min period, but the power of oscillations was unchanged in control experiments following vehicle injections. In addition, infusion of gap junction blockers had no significant effect on multi-unit activity, suggesting that the attenuation of low-frequency oscillations was likely due to reductions in electrical coupling rather than a decreased excitability within the granule cell layer. Our results indicate that electrical coupling among the Golgi cell networks in the cerebellar cortex contributes to the local circuit mechanisms that promote the occurrence of GCL LFP slow oscillations in the anesthetized rat.
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Affiliation(s)
- Jennifer Claire Robinson
- Department of Exercise Science, and the FRQS Groupe de Recherche en Neurobiologie Comportementale (CSBN), Concordia University, SP-165-03, 7141 Sherbrooke Street West, Montreal, QC, H4B 1R6, Canada
| | - C Andrew Chapman
- Department of Psychology, and the FRQS Groupe de Recherche en Neurobiologie Comportementale (CSBN), Concordia University, Montreal, Canada
| | - Richard Courtemanche
- Department of Exercise Science, and the FRQS Groupe de Recherche en Neurobiologie Comportementale (CSBN), Concordia University, SP-165-03, 7141 Sherbrooke Street West, Montreal, QC, H4B 1R6, Canada.
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27
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Wang W. Optogenetic manipulation of ENS - The brain in the gut. Life Sci 2017; 192:18-25. [PMID: 29155296 DOI: 10.1016/j.lfs.2017.11.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/25/2017] [Accepted: 11/07/2017] [Indexed: 12/19/2022]
Abstract
Optogenetics has emerged as an important tool in neuroscience, especially in central nervous system research. It allows for the study of the brain's highly complex network with high temporal and spatial resolution. The enteric nervous system (ENS), the brain in the gut, plays critical roles for life. Although advanced progress has been made, the neural circuits of the ENS remain only partly understood because the appropriate research tools are lacking. In this review, I highlight the potential application of optogenetics in ENS research. Firstly, I describe the development of optogenetics with focusing on its three main components. I discuss the applications in vitro and in vivo, and summarize current findings in the ENS research field obtained by optogenetics. Finally, the challenges for the application of optogenetics to the ENS research will be discussed.
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Affiliation(s)
- Wei Wang
- School of Biological Science and Biotechnology, Minnan Normal University, Zhangzhou 363000, China.
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28
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Concerted Interneuron Activity in the Cerebellar Molecular Layer During Rhythmic Oromotor Behaviors. J Neurosci 2017; 37:11455-11468. [PMID: 29066561 DOI: 10.1523/jneurosci.1091-17.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 10/10/2017] [Accepted: 10/17/2017] [Indexed: 01/02/2023] Open
Abstract
Molecular layer interneurons (MLIs, stellate and basket cells) of the cerebellar cortex are linked together by chemical and electrical synapses and exert a potent feedforward inhibition on Purkinje cells. The functional role of MLIs during specific motor tasks is uncertain. Here, we used two-photon imaging to study the patterns of activity of neighboring individual MLIs in the Crus II region of awake female mice during two types of oromotor activity, licking and bruxing, using specific expression of the genetically encoded calcium indicator protein GCaMP6s. We found that both stellate and basket cells engaged in synchronized waves of calcium activity during licking and bruxing, with high degrees of correlation among the signals collected in individual MLIs. In contrast, no calcium activity was observed during whisking. MLI activity tended to lag behind the onset of sustained licking episodes, indicating a regulatory action of MLIs during licking. Furthermore, during licking, stellate cell activity was anisotropic: the coordination was constant along the direction of parallel fibers (PFs), but fell off with distance along the orthogonal direction. These results suggest a PF drive for Ca2+ signals during licking. In contrast, during bruxing, MLI activity was neither clearly organized spatially nor temporally correlated with oromotor activity. In conclusion, MLI activity exhibits a high degree of correlation both in licking and in bruxing, but spatiotemporal patterns of activity display significant differences for the two types of behavior.SIGNIFICANCE STATEMENT It is known that, during movement, the activity of molecular layer interneurons (MLIs) of the cerebellar cortex is enhanced. However, MLI-MLI interactions are complex because they depend both from excitatory electrical synapses and from potentially inhibitory chemical synapses. Accordingly, the pattern of MLI activity during movement has been unclear. Here, during two oromotor tasks, licking and bruxism, individual neighboring MLIs displayed highly coordinated activity, showing that the positive influences binding MLIs together are predominant. We further find that spatiotemporal patterns differ between licking and bruxing, suggesting that the precise pattern of MLI activity depends on the nature of the motor task.
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29
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Wefers AK, Haberlandt C, Tekin NB, Fedorov DA, Timmermann A, van der Want JJL, Chaudhry FA, Steinhäuser C, Schilling K, Jabs R. Synaptic input as a directional cue for migrating interneuron precursors. Development 2017; 144:4125-4136. [PMID: 29061636 DOI: 10.1242/dev.154096] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 10/11/2017] [Indexed: 02/02/2023]
Abstract
During CNS development, interneuron precursors have to migrate extensively before they integrate in specific microcircuits. Known regulators of neuronal motility include classical neurotransmitters, yet the mechanisms that assure interneuron dispersal and interneuron/projection neuron matching during histogenesis remain largely elusive. We combined time-lapse video microscopy and electrophysiological analysis of the nascent cerebellum of transgenic Pax2-EGFP mice to address this issue. We found that cerebellar interneuronal precursors regularly show spontaneous postsynaptic currents, indicative of synaptic innervation, well before settling in the molecular layer. In keeping with the sensitivity of these cells to neurotransmitters, ablation of synaptic communication by blocking vesicular release in acute slices of developing cerebella slows migration. Significantly, abrogation of exocytosis primarily impedes the directional persistence of migratory interneuronal precursors. These results establish an unprecedented function of the early synaptic innervation of migrating neuronal precursors and demonstrate a role for synapses in the regulation of migration and pathfinding.
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Affiliation(s)
- Annika K Wefers
- Anatomisches Institut, Anatomie & Zellbiologie, Medizinische Fakultät, University of Bonn, 53115 Bonn, Germany.,Institut für Zelluläre Neurowissenschaften, Medizinische Fakultät, University of Bonn, 53105 Bonn, Germany
| | - Christian Haberlandt
- Institut für Zelluläre Neurowissenschaften, Medizinische Fakultät, University of Bonn, 53105 Bonn, Germany
| | - Nuriye B Tekin
- Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
| | - Dmitry A Fedorov
- Institut für Zelluläre Neurowissenschaften, Medizinische Fakultät, University of Bonn, 53105 Bonn, Germany
| | - Aline Timmermann
- Institut für Zelluläre Neurowissenschaften, Medizinische Fakultät, University of Bonn, 53105 Bonn, Germany
| | - Johannes J L van der Want
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Farrukh A Chaudhry
- Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
| | - Christian Steinhäuser
- Institut für Zelluläre Neurowissenschaften, Medizinische Fakultät, University of Bonn, 53105 Bonn, Germany
| | - Karl Schilling
- Anatomisches Institut, Anatomie & Zellbiologie, Medizinische Fakultät, University of Bonn, 53115 Bonn, Germany
| | - Ronald Jabs
- Institut für Zelluläre Neurowissenschaften, Medizinische Fakultät, University of Bonn, 53105 Bonn, Germany
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30
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Chen S, Augustine GJ, Chadderton P. Serial processing of kinematic signals by cerebellar circuitry during voluntary whisking. Nat Commun 2017; 8:232. [PMID: 28794450 PMCID: PMC5550418 DOI: 10.1038/s41467-017-00312-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 06/20/2017] [Indexed: 11/17/2022] Open
Abstract
Purkinje cells (PCs) in Crus 1 represent whisker movement via linear changes in firing rate, but the circuit mechanisms underlying this coding scheme are unknown. Here we examine the role of upstream inputs to PCs-excitatory granule cells (GCs) and inhibitory molecular layer interneurons-in processing of whisking signals. Patch clamp recordings in GCs reveal that movement is accompanied by changes in mossy fibre input rate that drive membrane potential depolarisation and high-frequency bursting activity at preferred whisker angles. Although individual GCs are narrowly tuned, GC populations provide linear excitatory drive across a wide range of movement. Molecular layer interneurons exhibit bidirectional firing rate changes during whisking, similar to PCs. Together, GC populations provide downstream PCs with linear representations of volitional movement, while inhibitory networks invert these signals. The exquisite sensitivity of neurons at each processing stage enables faithful propagation of kinematic representations through the cerebellum.Cerebellar Purkinje cells (PCs) linearly encode whisker position but the precise circuit mechanisms that generate these signals are not well understood. Here the authors use patch clamp recordings to show that selective tuning of granule cell inputs and bidirectional tuning of interneuron inputs are required to generate the kinematic representations in PCs.
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Affiliation(s)
- Susu Chen
- Department of Bioengineering and Centre for Neurotechnology, Imperial College London, London, SW7 2AZ, UK
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore.,Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore, 138673, Singapore
| | - Paul Chadderton
- Department of Bioengineering and Centre for Neurotechnology, Imperial College London, London, SW7 2AZ, UK.
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31
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Lo SQ, Sng JCG, Augustine GJ. Defining a critical period for inhibitory circuits within the somatosensory cortex. Sci Rep 2017; 7:7271. [PMID: 28779074 PMCID: PMC5544762 DOI: 10.1038/s41598-017-07400-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 06/28/2017] [Indexed: 11/21/2022] Open
Abstract
Although experience-dependent changes in brain inhibitory circuits are thought to play a key role during the “critical period” of brain development, the nature and timing of these changes are poorly understood. We examined the role of sensory experience in sculpting an inhibitory circuit in the primary somatosensory cortex (S1) of mice by using optogenetics to map the connections between parvalbumin (PV) expressing interneurons and layer 2/3 pyramidal cells. Unilateral whisker deprivation decreased the strength and spatial range of inhibitory input provided to pyramidal neurons by PV interneurons in layers 2/3, 4 and 5. By varying the time when sensory input was removed, we determined that the critical period closes around postnatal day 14. This yields the first precise time course of critical period plasticity for an inhibitory circuit.
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Affiliation(s)
- Shun Qiang Lo
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.,Institute of Molecular and Cell Biology (A*STAR), Singapore, Singapore.,Marine Biological Laboratory, Woods Hole, USA
| | - Judy C G Sng
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Singapore Institute of Clinical Sciences, Agency for Science and Technology (A*STAR), Singapore, Singapore
| | - George J Augustine
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. .,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore. .,Institute of Molecular and Cell Biology (A*STAR), Singapore, Singapore. .,Marine Biological Laboratory, Woods Hole, USA.
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32
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Optogenetic Visualization of Presynaptic Tonic Inhibition of Cerebellar Parallel Fibers. J Neurosci 2017; 36:5709-23. [PMID: 27225762 DOI: 10.1523/jneurosci.4366-15.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 03/31/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Tonic inhibition was imaged in cerebellar granule cells of transgenic mice expressing the optogenetic chloride indicator, Clomeleon. Blockade of GABAA receptors substantially reduced chloride concentration in granule cells due to block of tonic inhibition. This indicates that tonic inhibition is a significant contributor to the resting chloride concentration of these cells. Tonic inhibition was observed not only in granule cell bodies, but also in their axons, the parallel fibers (PFs). This presynaptic tonic inhibition could be observed in slices both at room and physiological temperatures, as well as in vivo, and has many of the same properties as tonic inhibition measured in granule cell bodies. GABA application revealed that PFs possess at least two types of GABAA receptor: one high-affinity receptor that is activated by ambient GABA and causes a chloride influx that mediates tonic inhibition, and a second with a low affinity for GABA that causes a chloride efflux that excites PFs. Presynaptic tonic inhibition regulates glutamate release from PFs because GABAA receptor blockade enhanced both the frequency of spontaneous EPSCs and the amplitude of evoked EPSCs at the PF-Purkinje cell synapse. We conclude that tonic inhibition of PFs could play an important role in regulating information flow though cerebellar synaptic circuits. Such cross talk between phasic and tonic signaling could be a general mechanism for fine tuning of synaptic circuits. SIGNIFICANCE STATEMENT This paper demonstrates that an unconventional form of signaling, known as tonic inhibition, is found in presynaptic terminals and affects conventional synaptic communication. Our results establish the basic characteristics and mechanisms of presynaptic tonic inhibition and show that it occurs in vivo as well as in isolated brain tissue.
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33
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Nagy JI, Rash JE. Cx36, Cx43 and Cx45 in mouse and rat cerebellar cortex: species-specific expression, compensation in Cx36 null mice and co-localization in neurons vs. glia. Eur J Neurosci 2017; 46:1790-1804. [PMID: 28561933 DOI: 10.1111/ejn.13614] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/13/2017] [Accepted: 05/24/2017] [Indexed: 12/13/2022]
Abstract
Electrical synapses formed by connexin36 (Cx36)-containing gap junctions between interneurons in the cerebellar cortex have been well characterized, including those formed between basket cells and between Golgi cells, and there is gene reporter-based evidence for the expression of connexin45 (Cx45) in the cerebellar molecular layer. Here, we used immunofluorescence approaches to further investigate expression patterns of Cx36 and Cx45 in this layer and to examine localization relationships of these connexins with each other and with glial connexin43 (Cx43). In mice, strain differences were found, such that punctate labelling for Cx36 was differentially distributed in the molecular layer of C57BL/6 vs. CD1 mice. In mice with EGFP reporter representing Cx36 expression, Cx36-puncta were localized to processes of stellate cells and other cerebellar interneurons. Punctate labelling of Cx45 was faint in the molecular layer of wild-type mice and was increased in intensity in mice with Cx36 gene ablation. The vast majority of Cx36-puncta co-localized with Cx45-puncta, which in turn was associated with the scaffolding protein zonula occludens-1. In rats, Cx45-puncta were also co-localized with Cx36-puncta and additionally occurred along Bergmann glial processes adjacent to Cx43-puncta. The results indicate strain and species differences in Cx36 as well as Cx45 expression, possible compensatory processes after loss of Cx36 expression and localization of Cx45 to both neuronal and Bergmann glial gap junctions. Further, expression of both Cx43 and Cx45 in Bergmann glia of rat may contribute to the complex properties of junctional coupling between these cells and perhaps to their reported coupling with Purkinje cells.
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Affiliation(s)
- J I Nagy
- Department of Physiology and Pathophysiology, Faculty of Medicine, University of Manitoba, 745 Bannatyne Ave, Winnipeg, MB, R3E 0J9, Canada
| | - J E Rash
- Department of Biomedical Sciences, and Program in Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, CO, USA
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Using c-kit to genetically target cerebellar molecular layer interneurons in adult mice. PLoS One 2017; 12:e0179347. [PMID: 28658323 PMCID: PMC5489153 DOI: 10.1371/journal.pone.0179347] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 05/26/2017] [Indexed: 11/19/2022] Open
Abstract
The cerebellar system helps modulate and fine-tune motor action. Purkinje cells (PCs) provide the sole output of the cerebellar cortex, therefore, any cerebellar involvement in motor activity must be driven by changes in PC firing rates. Several different cell types influence PC activity including excitatory input from parallel fibers and inhibition from molecular layer interneurons (MLIs). Similar to PCs, MLI activity is driven by parallel fibers, therefore, MLIs provide feed-forward inhibition onto PCs. To aid in the experimental assessment of how molecular layer inhibition contributes to cerebellar function and motor behavior, we characterized a new knock-in mouse line with Cre recombinase expression under control of endogenous c-kit transcriptional machinery. Using these engineered c-Kit mice, we were able to obtain high levels of conditional MLI transduction in adult mice using Cre-dependent viral vectors without any PC or granule cell labeling. We then used the mouse line to target MLIs for activity perturbation in vitro using opto- and chemogenetics.
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35
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Maex R, Gutkin B. Temporal integration and 1/ f power scaling in a circuit model of cerebellar interneurons. J Neurophysiol 2017; 118:471-485. [PMID: 28446587 DOI: 10.1152/jn.00789.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 03/29/2017] [Accepted: 04/22/2017] [Indexed: 11/22/2022] Open
Abstract
Inhibitory interneurons interconnected via electrical and chemical (GABAA receptor) synapses form extensive circuits in several brain regions. They are thought to be involved in timing and synchronization through fast feedforward control of principal neurons. Theoretical studies have shown, however, that whereas self-inhibition does indeed reduce response duration, lateral inhibition, in contrast, may generate slow response components through a process of gradual disinhibition. Here we simulated a circuit of interneurons (stellate and basket cells) of the molecular layer of the cerebellar cortex and observed circuit time constants that could rise, depending on parameter values, to >1 s. The integration time scaled both with the strength of inhibition, vanishing completely when inhibition was blocked, and with the average connection distance, which determined the balance between lateral and self-inhibition. Electrical synapses could further enhance the integration time by limiting heterogeneity among the interneurons and by introducing a slow capacitive current. The model can explain several observations, such as the slow time course of OFF-beam inhibition, the phase lag of interneurons during vestibular rotation, or the phase lead of Purkinje cells. Interestingly, the interneuron spike trains displayed power that scaled approximately as 1/f at low frequencies. In conclusion, stellate and basket cells in cerebellar cortex, and interneuron circuits in general, may not only provide fast inhibition to principal cells but also act as temporal integrators that build a very short-term memory.NEW & NOTEWORTHY The most common function attributed to inhibitory interneurons is feedforward control of principal neurons. In many brain regions, however, the interneurons are densely interconnected via both chemical and electrical synapses but the function of this coupling is largely unknown. Based on large-scale simulations of an interneuron circuit of cerebellar cortex, we propose that this coupling enhances the integration time constant, and hence the memory trace, of the circuit.
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Affiliation(s)
- Reinoud Maex
- Department of Cognitive Sciences, École Normale Supérieure, PSL Research University, Paris, France; and
| | - Boris Gutkin
- Department of Cognitive Sciences, École Normale Supérieure, PSL Research University, Paris, France; and.,Centre for Cognition and Decision Making, Higher School of Economics, Moscow, Russian Federation
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Movement Rate Is Encoded and Influenced by Widespread, Coherent Activity of Cerebellar Molecular Layer Interneurons. J Neurosci 2017; 37:4751-4765. [PMID: 28389475 DOI: 10.1523/jneurosci.0534-17.2017] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 03/31/2017] [Accepted: 04/02/2017] [Indexed: 11/21/2022] Open
Abstract
Inhibition from molecular layer interneurons (MLIs) is thought to play an important role in cerebellar function by sharpening the precision of Purkinje cell spike output. Yet the coding features of MLIs during behavior are poorly understood. To study MLI activity, we used in vivo Ca2+ imaging in head-fixed mice during the performance of a rhythmic motor behavior, licking during water consumption. MLIs were robustly active during lick-related movement across a lobule-specific region of the cerebellum showing high temporal correspondence within their population. Average MLI Ca2+ activity strongly correlated with movement rate but not to the intentional, or unexpected, adjustment of lick position or to sensory feedback that varied with task condition. Chemogenetic suppression of MLI output reduced lick rate and altered tongue movements, indicating that activity of these interneurons not only encodes temporal aspects of movement kinematics but also influences motor outcome pointing to an integral role in online control of rhythmic behavior.SIGNIFICANCE STATEMENT The cerebellum helps fine-tune coordinated motor actions via signaling from projection neurons called Purkinje cells. Molecular layer interneurons (MLIs) provide powerful inhibition onto Purkinje cells, but little is understood about how this inhibitory circuit is engaged during behavior or what type of information is transmitted through these neurons. Our work establishes that MLIs in the lateral cerebellum are broadly activated during movement with calcium activity corresponding to movement rate. We also show that suppression of MLI output slows and disorganizes the precise movement pattern. Therefore, MLIs are an important circuit element in the cerebellum allowing for accurate motor control.
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37
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Zhang X, Sullivan CS, Kratz MB, Kasten MR, Maness PF, Manis PB. NCAM Regulates Inhibition and Excitability in Layer 2/3 Pyramidal Cells of Anterior Cingulate Cortex. Front Neural Circuits 2017; 11:19. [PMID: 28386219 PMCID: PMC5362729 DOI: 10.3389/fncir.2017.00019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 03/06/2017] [Indexed: 11/29/2022] Open
Abstract
The neural cell adhesion molecule (NCAM), has been shown to be an obligate regulator of synaptic stability and pruning during critical periods of cortical maturation. However, the functional consequences of NCAM deletion on the organization of inhibitory circuits in cortex are not known. In vesicular gamma-amino butyric acid (GABA) transporter (VGAT)-channelrhodopsin2 (ChR2)-enhanced yellow fluorescent protein (EYFP) transgenic mice, NCAM is expressed postnatally at perisomatic synaptic puncta of EYFP-labeled parvalbumin, somatostatin and calretinin-positive interneurons, and in the neuropil in the anterior cingulate cortex (ACC). To investigate how NCAM deletion affects the spatial organization of inhibitory inputs to pyramidal cells, we used laser scanning photostimulation in brain slices of VGAT-ChR2-EYFP transgenic mice crossed to either NCAM-null or wild type (WT) mice. Laser scanning photostimulation revealed that NCAM deletion increased the strength of close-in inhibitory connections to layer 2/3 pyramidal cells of the ACC. In addition, in NCAM-null mice, the intrinsic excitability of pyramidal cells increased, whereas the intrinsic excitability of GABAergic interneurons did not change. The increase in inhibitory tone onto pyramidal cells, and the increased pyramidal cell excitability in NCAM-null mice will alter the delicate coordination of excitation and inhibition (E/I coordination) in the ACC, and may be a factor contributing to circuit dysfunction in diseases such as schizophrenia and bipolar disorder, in which NCAM has been implicated.
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Affiliation(s)
- Xuying Zhang
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Chelsea S Sullivan
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Megan B Kratz
- Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Michael R Kasten
- Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Patricia F Maness
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Paul B Manis
- Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel HillChapel Hill, NC, USA; Department of Cell Biology and Physiology, The University of North Carolina at Chapel HillChapel Hill, NC, USA
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38
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Leppä E, Linden AM, Aller MI, Wulff P, Vekovischeva O, Luscher B, Lüddens H, Wisden W, Korpi ER. Increased Motor-Impairing Effects of the Neuroactive Steroid Pregnanolone in Mice with Targeted Inactivation of the GABA A Receptor γ2 Subunit in the Cerebellum. Front Pharmacol 2016; 7:403. [PMID: 27833556 PMCID: PMC5081378 DOI: 10.3389/fphar.2016.00403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 10/12/2016] [Indexed: 11/20/2022] Open
Abstract
Endogenous neurosteroids and neuroactive steroids have potent and widespread actions on the brain via inhibitory GABAA receptors. In recombinant receptors and genetic mouse models their actions depend on the α, β, and δ subunits of the receptor, especially on those that form extrasynaptic GABAA receptors responsible for non-synaptic (tonic) inhibition, but they also act on synaptically enriched γ2 subunit-containing receptors and even on αβ binary receptors. Here we tested whether behavioral sensitivity to the neuroactive steroid agonist 5β-pregnan-3α-ol-20-one is altered in genetically engineered mouse models that have deficient GABAA receptor-mediated synaptic inhibition in selected neuronal populations. Mouse lines with the GABAA receptor γ2 subunit gene selectively deleted either in parvalbumin-containing cells (including cerebellar Purkinje cells), cerebellar granule cells, or just in cerebellar Purkinje cells were trained on the accelerated rotating rod and then tested for motor impairment after cumulative intraperitoneal dosing of 5β-pregnan-3α-ol-20-one. Motor-impairing effects of 5β-pregnan-3α-ol-20-one were strongly increased in all three mouse models in which γ2 subunit-dependent synaptic GABAA responses in cerebellar neurons were genetically abolished. Furthermore, rescue of postsynaptic GABAA receptors in Purkinje cells normalized the effect of the steroid. Anxiolytic/explorative effects of the steroid in elevated plus maze and light:dark exploration tests in mice with Purkinje cell γ2 subunit inactivation were similar to those in control mice. The results suggest that, when the deletion of γ2 subunit has removed synaptic GABAA receptors from the specific cerebellar neuronal populations, the effects of neuroactive steroids solely on extrasynaptic αβ or αβδ receptors lead to enhanced changes in the cerebellum-generated behavior.
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Affiliation(s)
- Elli Leppä
- Department of Pharmacology, Faculty of Medicine, University of Helsinki Helsinki, Finland
| | - Anni-Maija Linden
- Department of Pharmacology, Faculty of Medicine, University of Helsinki Helsinki, Finland
| | - Maria I Aller
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández de Elche San Juan de Alicante, Spain
| | - Peer Wulff
- Institute of Physiology, University of Kiel Kiel, Germany
| | - Olga Vekovischeva
- Department of Pharmacology, Faculty of Medicine, University of Helsinki Helsinki, Finland
| | - Bernhard Luscher
- Department of Biology, The Pennsylvania State University University Park, PA, USA
| | - Hartmut Lüddens
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University Mainz Mainz, Germany
| | - William Wisden
- Department of Life Sciences, Imperial College London London, UK
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki Helsinki, Finland
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Cho YK, Zheng G, Augustine GJ, Hochbaum D, Cohen A, Knöpfel T, Pisanello F, Pavone FS, Vellekoop IM, Booth MJ, Hu S, Zhu J, Chen Z, Hoshi Y. Roadmap on neurophotonics. JOURNAL OF OPTICS (2010) 2016; 18:093007. [PMID: 28386392 PMCID: PMC5378317 DOI: 10.1088/2040-8978/18/9/093007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Mechanistic understanding of how the brain gives rise to complex behavioral and cognitive functions is one of science's grand challenges. The technical challenges that we face as we attempt to gain a systems-level understanding of the brain are manifold. The brain's structural complexity requires us to push the limit of imaging resolution and depth, while being able to cover large areas, resulting in enormous data acquisition and processing needs. Furthermore, it is necessary to detect functional activities and 'map' them onto the structural features. The functional activity occurs at multiple levels, using electrical and chemical signals. Certain electrical signals are only decipherable with sub-millisecond timescale resolution, while other modes of signals occur in minutes to hours. For these reasons, there is a wide consensus that new tools are necessary to undertake this daunting task. Optical techniques, due to their versatile and scalable nature, have great potentials to answer these challenges. Optical microscopy can now image beyond the diffraction limit, record multiple types of brain activity, and trace structural features across large areas of tissue. Genetically encoded molecular tools opened doors to controlling and detecting neural activity using light in specific cell types within the intact brain. Novel sample preparation methods that reduce light scattering have been developed, allowing whole brain imaging in rodent models. Adaptive optical methods have the potential to resolve images from deep brain regions. In this roadmap article, we showcase a few major advances in this area, survey the current challenges, and identify potential future needs that may be used as a guideline for the next steps to be taken.
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Affiliation(s)
- Yong Ku Cho
- Department of Chemical and Biomolecular Engineering, Institute for Systems Genomics, University of Connecticut, 191 Auditorium Rd, Storrs, CT 06269-3222, USA
| | - Guoan Zheng
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Singapore 637553, Singapore
| | - Daniel Hochbaum
- Departments of Chemistry and Chemical Biology and Physics, Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Adam Cohen
- Departments of Chemistry and Chemical Biology and Physics, Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA
| | - Thomas Knöpfel
- Division of Brain Sciences, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Ferruccio Pisanello
- Istituto Italiano di Tecnologia (IIT), Center for Biomolecular Nanotechnologies, Via Barsanti sn, I-73010 Arnesano (Lecce), Italy
| | - Francesco S Pavone
- European Laboratory for Non Linear Spectroscopy, University of Florence, Via N. Carrara 1, I-50019 Sesto Fiorentino (FI), Italy; Department of Physics, University of Florence, Via G. Sansone 1, I-50019 Sesto Fiorentino, Italy; Istituto Nazionale di Ottica, L.go E. fermi 2, I-50100 Firenze, Italy
| | - Ivo M Vellekoop
- Biomedical Photonic Imaging group, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Martin J Booth
- Centre for Neural Circuits and Behaviour, University of Oxford, Mansfield Road, Oxford OX1 3SR, UK; Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Song Hu
- Department of Biomedical Engineering, University of Virginia, 415 Lane Road, Charlottesville, VA 22908, USA
| | - Jiang Zhu
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92617, USA
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92617, USA
| | - Yoko Hoshi
- Department of Biomedical Optics, Institute for Medical Photonics Research, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
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D'Angelo E, Antonietti A, Casali S, Casellato C, Garrido JA, Luque NR, Mapelli L, Masoli S, Pedrocchi A, Prestori F, Rizza MF, Ros E. Modeling the Cerebellar Microcircuit: New Strategies for a Long-Standing Issue. Front Cell Neurosci 2016; 10:176. [PMID: 27458345 PMCID: PMC4937064 DOI: 10.3389/fncel.2016.00176] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/23/2016] [Indexed: 11/13/2022] Open
Abstract
The cerebellar microcircuit has been the work bench for theoretical and computational modeling since the beginning of neuroscientific research. The regular neural architecture of the cerebellum inspired different solutions to the long-standing issue of how its circuitry could control motor learning and coordination. Originally, the cerebellar network was modeled using a statistical-topological approach that was later extended by considering the geometrical organization of local microcircuits. However, with the advancement in anatomical and physiological investigations, new discoveries have revealed an unexpected richness of connections, neuronal dynamics and plasticity, calling for a change in modeling strategies, so as to include the multitude of elementary aspects of the network into an integrated and easily updatable computational framework. Recently, biophysically accurate “realistic” models using a bottom-up strategy accounted for both detailed connectivity and neuronal non-linear membrane dynamics. In this perspective review, we will consider the state of the art and discuss how these initial efforts could be further improved. Moreover, we will consider how embodied neurorobotic models including spiking cerebellar networks could help explaining the role and interplay of distributed forms of plasticity. We envisage that realistic modeling, combined with closed-loop simulations, will help to capture the essence of cerebellar computations and could eventually be applied to neurological diseases and neurorobotic control systems.
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Affiliation(s)
- Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy; Brain Connectivity Center, C. Mondino National Neurological InstitutePavia, Italy
| | - Alberto Antonietti
- NearLab - NeuroEngineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano Milano, Italy
| | - Stefano Casali
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy
| | - Claudia Casellato
- NearLab - NeuroEngineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano Milano, Italy
| | - Jesus A Garrido
- Department of Computer Architecture and Technology, University of Granada Granada, Spain
| | - Niceto Rafael Luque
- Department of Computer Architecture and Technology, University of Granada Granada, Spain
| | - Lisa Mapelli
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy
| | - Stefano Masoli
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy
| | - Alessandra Pedrocchi
- NearLab - NeuroEngineering and Medical Robotics Laboratory, Department of Electronics, Information and Bioengineering, Politecnico di Milano Milano, Italy
| | - Francesca Prestori
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy
| | - Martina Francesca Rizza
- Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy; Dipartimento di Informatica, Sistemistica e Comunicazione, Università degli Studi di Milano-BicoccaMilan, Italy
| | - Eduardo Ros
- Department of Computer Architecture and Technology, University of Granada Granada, Spain
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Blot A, de Solages C, Ostojic S, Szapiro G, Hakim V, Léna C. Time-invariant feed-forward inhibition of Purkinje cells in the cerebellar cortex in vivo. J Physiol 2016; 594:2729-49. [PMID: 26918702 DOI: 10.1113/jp271518] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 02/15/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS We performed extracellular recording of pairs of interneuron-Purkinje cells in vivo. A single interneuron produces a substantial, short-lasting, inhibition of Purkinje cells. Feed-forward inhibition is associated with characteristic asymmetric cross-correlograms. In vivo, Purkinje cell spikes only depend on the most recent synaptic activity. ABSTRACT Cerebellar molecular layer interneurons are considered to control the firing rate and spike timing of Purkinje cells. However, interactions between these cell types are largely unexplored in vivo. Using tetrodes, we performed simultaneous extracellular recordings of neighbouring Purkinje cells and molecular layer interneurons, presumably basket cells, in adult rats in vivo. The high levels of afferent synaptic activity encountered in vivo yield irregular spiking and reveal discharge patterns characteristic of feed-forward inhibition, thus suggesting an overlap of the afferent excitatory inputs between Purkinje cells and basket cells. Under conditions of intense background synaptic inputs, interneuron spikes exert a short-lasting inhibitory effect, delaying the following Purkinje cell spike by an amount remarkably independent of the Purkinje cell firing cycle. This effect can be explained by the short memory time of the Purkinje cell potential as a result of the intense incoming synaptic activity. Finally, we found little evidence for any involvement of the interneurons that we recorded with the cerebellar high-frequency oscillations promoting Purkinje cell synchrony. The rapid interactions between interneurons and Purkinje cells might be of particular importance in fine motor control because the inhibitory action of interneurons on Purkinje cells leads to deep cerebellar nuclear disinhibition and hence increased cerebellar output.
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Affiliation(s)
- Antonin Blot
- IBENS, École Normale Supérieure, PSL Research University, CNRS, INSERM, Paris, France
| | - Camille de Solages
- IBENS, École Normale Supérieure, PSL Research University, CNRS, INSERM, Paris, France
| | - Srdjan Ostojic
- Laboratoire de Neurosciences Cognitives, École Normale Supérieure, PSL Research University, CNRS, INSERM, Paris, France
| | - German Szapiro
- IBENS, École Normale Supérieure, PSL Research University, CNRS, INSERM, Paris, France
| | - Vincent Hakim
- Laboratoire de Physique Statistique, École Normale Supérieure, PSL Research University, CNRS, Paris, France.,Sorbonne Universités, UPMC Université, Paris, France.,Sorbonne Paris Cité, Université Paris Diderot, Paris, France
| | - Clément Léna
- IBENS, École Normale Supérieure, PSL Research University, CNRS, INSERM, Paris, France
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Selective Loss of Presynaptic Potassium Channel Clusters at the Cerebellar Basket Cell Terminal Pinceau in Adam11 Mutants Reveals Their Role in Ephaptic Control of Purkinje Cell Firing. J Neurosci 2015; 35:11433-44. [PMID: 26269648 DOI: 10.1523/jneurosci.1346-15.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED A specialized axonal ending, the basket cell "pinceau," encapsulates the Purkinje cell axon initial segment (AIS), exerting final inhibitory control over the integrated outflow of the cerebellar cortex. This nonconventional axo-axonic contact extends beyond the perisomatic chemical GABAergic synaptic boutons to the distal AIS, lacks both sodium channels and local exocytotic machinery, and yet contains a dense cluster of voltage-gated potassium channels whose functional contribution is unknown. Here, we show that ADAM11, a transmembrane noncatalytic disintegrin, is the first reported Kv1-interacting protein essential for localizing Kv1.1 and Kv1.2 subunit complexes to the distal terminal. Selective absence of these channels at the pinceau due to mutation of ADAM11 spares spontaneous GABA release from basket cells at the perisomatic synapse yet eliminates ultrarapid ephaptic inhibitory synchronization of Purkinje cell firing. Our findings identify a critical role for presynaptic K(+) channels at the pinceau in ephaptic control over the speed and stability of spike rate coding at the Purkinje cell AIS in mice. SIGNIFICANCE STATEMENT This study identifies ADAM11 as the first essential molecule for the proper localization of potassium ion channels at presynaptic nerve terminals, where they modulate excitability and the release of neural transmitters. Genetic truncation of the transmembrane disintegrin and metalloproteinase protein ADAM11 resulted in the absence of Kv1 channels that are normally densely clustered at the terminals of basket cell axons in the cerebellar cortex. These specialized terminals are responsible for the release of the neurotransmitter GABA onto Purkinje cells and also display electrical signaling. In the ADAM11 mutant, GABAergic release was not altered, but the ultrarapid electrical signal was absent, demonstrating that the dense presynaptic cluster of Kv1 ion channels at these terminals mediate electrical transmission. Therefore, ADAM11 plays a critical role at this central synapse.
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Sotelo C. Molecular layer interneurons of the cerebellum: developmental and morphological aspects. CEREBELLUM (LONDON, ENGLAND) 2015; 14:534-56. [PMID: 25599913 DOI: 10.1007/s12311-015-0648-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
During the past 25 years, our knowledge on the development of basket and stellate cells (molecular layer interneurons [MLIs]) has completely changed, not only regarding their origin from the ventricular zone, corresponding to the primitive cerebellar neuroepithelium, instead of the external granular layer, but above all by providing an almost complete account of the genetic regulations (transcription factors and other genes) involved in their differentiation and synaptogenesis. Moreover, it has been shown that MLIs' precursors (dividing neuroblasts) and not young postmitotic neurons, as in other germinal neuroepithelia, leave the germinative zone and migrate all along a complex and lengthy path throughout the presumptive cerebellar white matter, which provides suitable niches exerting epigenetic influences on their ultimate neuronal identities. Recent studies carried out on the anatomical-functional properties of adult MLIs emphasize the importance of these interneurons in regulating PC inhibition, and point out the crucial role played by electrical synaptic transmission between MLIs as well as ephaptic interactions between them and Purkinje cells at the pinceaux level, in the regulation of this inhibition.
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Affiliation(s)
- Constantino Sotelo
- INSERM, UMRS_U968, Institut de la Vision, 17 Rue Moreau, Paris, 75012, France.
- Institut de la Vision, Sorbonne Université, UPMC Univ Paris 06, Paris, 75012, France.
- CNRS, UMR_7210, Paris, 75012, France.
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Miguel Hernández (UMH), Avenida Ramón y Cajal s/n, 03550, San Juan de Alicante, Spain.
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Astorga G, Bao J, Marty A, Augustine GJ, Franconville R, Jalil A, Bradley J, Llano I. An excitatory GABA loop operating in vivo. Front Cell Neurosci 2015; 9:275. [PMID: 26236197 PMCID: PMC4503922 DOI: 10.3389/fncel.2015.00275] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 07/05/2015] [Indexed: 11/14/2022] Open
Abstract
While it has been proposed that the conventional inhibitory neurotransmitter GABA can be excitatory in the mammalian brain, much remains to be learned concerning the circumstances and the cellular mechanisms governing potential excitatory GABA action. Using a combination of optogenetics and two-photon calcium imaging in vivo, we find that activation of chloride-permeable GABAA receptors in parallel fibers (PFs) of the cerebellar molecular layer of adult mice causes parallel fiber excitation. Stimulation of PFs at submaximal stimulus intensities leads to GABA release from molecular layer interneurons (MLIs), thus creating a positive feedback loop that enhances excitation near the center of an activated PF bundle. Our results imply that elevated chloride concentration can occur in specific intracellular compartments of mature mammalian neurons and suggest an excitatory role for GABAA receptors in the cerebellar cortex of adult mice.
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Affiliation(s)
- Guadalupe Astorga
- Laboratory of Cerebral Physiology, CNRS and University Paris Descartes Paris, France
| | - Jin Bao
- Laboratory of Cerebral Physiology, CNRS and University Paris Descartes Paris, France
| | - Alain Marty
- Laboratory of Cerebral Physiology, CNRS and University Paris Descartes Paris, France
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore ; Institute of Molecular and Cell Biology Singapore, Singapore ; Center for Functional Connectomics, Korea Institute of Science and Technology Seoul, South Korea
| | - Romain Franconville
- Laboratory of Cerebral Physiology, CNRS and University Paris Descartes Paris, France
| | - Abdelali Jalil
- Laboratory of Cerebral Physiology, CNRS and University Paris Descartes Paris, France
| | - Jonathan Bradley
- Laboratory of Cerebral Physiology, CNRS and University Paris Descartes Paris, France
| | - Isabel Llano
- Laboratory of Cerebral Physiology, CNRS and University Paris Descartes Paris, France
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Spatially Selective Holographic Photoactivation and Functional Fluorescence Imaging in Freely Behaving Mice with a Fiberscope. Neuron 2014; 84:1157-69. [DOI: 10.1016/j.neuron.2014.11.005] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2014] [Indexed: 02/03/2023]
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Tsuda S, Kee MZL, Cunha C, Kim J, Yan P, Loew LM, Augustine GJ. Probing the function of neuronal populations: combining micromirror-based optogenetic photostimulation with voltage-sensitive dye imaging. Neurosci Res 2013; 75:76-81. [PMID: 23254260 PMCID: PMC3594342 DOI: 10.1016/j.neures.2012.11.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 11/27/2012] [Accepted: 11/28/2012] [Indexed: 11/25/2022]
Abstract
Recent advances in our understanding of brain function have come from using light to either control or image neuronal activity. Here we describe an approach that combines both techniques: a micromirror array is used to photostimulate populations of presynaptic neurons expressing channelrhodopsin-2, while a red-shifted voltage-sensitive dye allows optical detection of resulting postsynaptic activity. Such technology allowed us to control the activity of cerebellar interneurons while simultaneously recording inhibitory responses in multiple Purkinje neurons, their postsynaptic targets. This approach should substantially accelerate our understanding of information processing by populations of neurons within brain circuits.
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Affiliation(s)
- Sachiko Tsuda
- Laboratory of Synaptic Circuitry, Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, Singapore
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