1
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Pham NC, Kim YG, Kim SJ, Kim CH. Effect of a differential training paradigm with varying frequencies and amplitudes on adaptation of vestibulo-ocular reflex in mice. Exp Brain Res 2023; 241:1299-1308. [PMID: 37000203 DOI: 10.1007/s00221-023-06601-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 03/17/2023] [Indexed: 04/01/2023]
Abstract
The vestibulo-ocular reflex (VOR) functions to maintain eye stability during head movement, and VOR gain can be dynamically increased or decreased by gain-up or gain-down adaptation. In this study, we investigated the impact of a differential training paradigm with varying frequencies and amplitudes on the level of VOR adaptation in mice. Training for gain-up (out of phase) or gain-down (in phase) VOR adaptation was applied for 60 min using two protocols: (1) oscillation of a drum and turntable with fixed frequency and differing amplitudes (0.5 Hz/2.5°, 0.5 Hz/5° and 0.5 Hz/10°). (2) Oscillation of a drum and turntable with fixed amplitude and a differing frequency (0.25 Hz/5°, 0.5 Hz/5° and 1 Hz/5°). VOR adaptation occurred distinctively in gain-up and gain-down learning. In gain-up VOR adaptation, the learned increase in VOR gain was greatest when trained with the same frequency and amplitude as the test stimulation, and VOR gain decreased after gain-up training with too high a frequency or amplitude. In gain-down VOR adaptation, the decrease in VOR gain increased as the training frequency or amplitude increased. These results suggest that different mechanisms are, at least in part, involved in gain-up and gain-down VOR adaptation.
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Affiliation(s)
- Ngoc Chien Pham
- Department of Otorhinolaryngology-Head and Neck Surgery, Konkuk University Medical Center, Research Institute of Medical Science, Konkuk University School of Medicine, 120-1 Neungdong-ro, Gwangjin-gu, Seoul, 05030, Republic of Korea
| | - Yong Gyu Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
- Memory Network Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sang Jeong Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
- Memory Network Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
- Neuroscience Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Chang-Hee Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Konkuk University Medical Center, Research Institute of Medical Science, Konkuk University School of Medicine, 120-1 Neungdong-ro, Gwangjin-gu, Seoul, 05030, Republic of Korea.
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2
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Expression of a Form of Cerebellar Motor Memory Requires Learned Alterations to the Activity of Inhibitory Molecular Layer Interneurons. J Neurosci 2023; 43:601-612. [PMID: 36639897 PMCID: PMC9888511 DOI: 10.1523/jneurosci.0731-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 11/30/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
Procedural memories formed in the cerebellum in response to motor errors depend on changes to Purkinje cell (PC) spiking patterns that correct movement when the erroneous context is repeated. Because molecular layer interneurons (MLIs) inhibit PCs, learning-induced changes to MLI output may participate in reshaping PC spiking patterns. However, it remains unclear whether error-driven learning alters MLI activity and whether such changes are necessary for the memory engram. We addressed this knowledge gap by measuring and manipulating MLI activity in the flocculus of both sexes of mice before and after vestibulo-ocular reflex (VOR) adaptation. We found that MLIs are activated during vestibular stimuli and that their population response exhibits a phase shift after the instantiation of gain-increase VOR adaptation, a type of error-driven learning thought to require climbing-fiber-mediated instructive signaling. Although acute optogenetic suppression of MLI activity did not affect baseline VOR performance, it negated the expression of gain-increase learning, demonstrating a specific role of MLI activity changes in motor memory expression. This effect was transitory; after a multiday consolidation period, the expression of VOR gain-increase learning was no longer sensitive to MLI activity suppression. Together, our results indicate that error-driven alteration of MLI activity is necessary for labile, climbing-fiber-induced motor memory expression.SIGNIFICANCE STATEMENT In the cerebellum, motor learning induces an associative memory of the sensorimotor context of an erroneous movement that, when recalled, results in a new pattern of output that improves subsequent trials of performance. Our study shows that error-driven motor learning induces changes to the activity pattern of cerebellar molecular layer interneurons (MLIs) and that this new pattern of activity is required to express the corrective motor memory.
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Mitoma H, Manto M. Advances in the Pathogenesis of Auto-antibody-Induced Cerebellar Synaptopathies. CEREBELLUM (LONDON, ENGLAND) 2023; 22:129-147. [PMID: 35064896 PMCID: PMC9883363 DOI: 10.1007/s12311-021-01359-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 12/12/2021] [Indexed: 02/07/2023]
Abstract
The presence of auto-antibodies that target synaptic machinery proteins was documented recently in immune-mediated cerebellar ataxias. The autoantigens include glutamic acid decarboxylase 65 (GAD65), voltage-gated Ca2+ channel (VGCC), metabotropic glutamate receptor type 1 (mGluR1), and glutamate receptor delta (GluRdelta). GAD65 is involved in the synthesis, packaging, and release of GABA, whereas the other three play important roles in the induction of long-term depression (LTD). Thus, the auto-antibodies toward these synaptic molecules likely impair fundamental synaptic machineries involved in unique functions of the cerebellum, potentially leading to the development of cerebellar ataxias (CAs). This concept has been substantiated recently by a series of physiological studies. Anti-GAD65 antibody (Ab) acts on the terminals of inhibitory neurons that suppress GABA release, whereas anti-VGCC, anti-mGluR1, and anti-GluR Abs impair LTD induction. Notably, the mechanisms that link synaptic dysfunction with the manifestations of CAs can be explained by disruption of the "internal models." The latter can be divided into three levels. First, since chained inhibitory neurons shape the output signals through the mechanism of disinhibition/inhibition, impairments of GABA release and LTD distort the conversion process from the "internal model" to the output signals. Second, these antibodies impair the induction of synaptic plasticity, rebound potentiation, and LTD, on Purkinje cells, resulting in loss of restoration and compensation of the distorted "internal models." Finally, the cross-talk between glutamate and microglia/astrocytes could involve a positive feedback loop that accelerates excitotoxicity. This mini-review summarizes the pathophysiological mechanisms and aims to establish the basis of "auto-antibody-induced cerebellar synaptopathies."
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Affiliation(s)
- Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University, Tokyo, Japan
| | - Mario Manto
- Unité des Ataxies Cérébelleuses, Service de Neurologie, Médiathèque Jean Jacquy, CHU-Charleroi, 6000 Charleroi, Belgium ,Service des Neurosciences, University of Mons, 7000 Mons, Belgium
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4
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Regulation of GABA A Receptors Induced by the Activation of L-Type Voltage-Gated Calcium Channels. MEMBRANES 2021; 11:membranes11070486. [PMID: 34209589 PMCID: PMC8304739 DOI: 10.3390/membranes11070486] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/23/2021] [Accepted: 06/25/2021] [Indexed: 12/30/2022]
Abstract
GABAA receptors are pentameric ion channels that mediate most synaptic and tonic extrasynaptic inhibitory transmissions in the central nervous system. There are multiple GABAA receptor subtypes constructed from 19 different subunits in mammals that exhibit different regional and subcellular distributions and distinct pharmacological properties. Dysfunctional alterations of GABAA receptors are associated with various neuropsychiatric disorders. Short- and long-term plastic changes in GABAA receptors can be induced by the activation of different intracellular signaling pathways that are triggered, under physiological and pathological conditions, by calcium entering through voltage-gated calcium channels. This review discusses several mechanisms of regulation of GABAA receptor function that result from the activation of L-type voltage gated calcium channels. Calcium influx via these channels activates different signaling cascades that lead to changes in GABAA receptor transcription, phosphorylation, trafficking, and synaptic clustering, thus regulating the inhibitory synaptic strength. These plastic mechanisms regulate the interplay of synaptic excitation and inhibition that is crucial for the normal function of neuronal circuits.
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5
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Mitoma H, Kakei S, Yamaguchi K, Manto M. Physiology of Cerebellar Reserve: Redundancy and Plasticity of a Modular Machine. Int J Mol Sci 2021; 22:4777. [PMID: 33946358 PMCID: PMC8124536 DOI: 10.3390/ijms22094777] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 04/28/2021] [Accepted: 04/28/2021] [Indexed: 12/31/2022] Open
Abstract
The cerebellum is endowed with the capacity for compensation and restoration after pathological injury, a property known as cerebellar reserve. Such capacity is attributed to two unique morphological and physiological features of the cerebellum. First, mossy fibers that convey peripheral and central information run mediolaterally over a wide area of the cerebellum, resulting in the innervation of multiple microzones, commonly known as cerebellar functional units. Thus, a single microzone receives redundant information that can be used in pathological conditions. Secondly, the circuitry is characterized by a co-operative interplay among various forms of synaptic plasticity. Recent progress in understanding the mechanisms of redundant information and synaptic plasticity has allowed outlining therapeutic strategies potentiating these neural substrates to enhance the cerebellar reserve, taking advantage of the unique physiological properties of the cerebellum which appears as a modular and potentially reconfiguring brain structure.
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Affiliation(s)
- Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University, Tokyo 160-8402, Japan
| | - Shinji Kakei
- Laboratory for Movement Disorders, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan;
| | - Kazuhiko Yamaguchi
- Department of Ultrastructural Research, National Center of Neurology and Psychiatry, National Institute of Neuroscience, Tokyo 187-8551, Japan;
| | - Mario Manto
- Unité des Ataxies Cérébelleuses, Service de Neurologie, Médiathèque Jean Jacquy, CHU-Charleroi, 6000 Charleroi, Belgium;
- Service des Neurosciences, University of Mons, 7000 Mons, Belgium
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6
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Canepari M. Is Purkinje Neuron Hyperpolarisation Important for Cerebellar Synaptic Plasticity? A Retrospective and Prospective Analysis. THE CEREBELLUM 2020; 19:869-878. [PMID: 32654026 DOI: 10.1007/s12311-020-01164-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two recent studies have demonstrated that the dendritic Ca2+ signal associated with a climbing fibre (CF) input to the cerebellar Purkinje neuron (PN) depends on the membrane potential (Vm). Specifically, when the cell is hyperpolarised, this signal is mediated by T-type voltage-gated Ca2+ channels; in contrast, when the cell is firing, the CF-PN signal is mediated by P/Q-type voltage-gated Ca2+ channels. When the CF input is paired with parallel fibre (PF) activity, the signal is locally amplified at the sites of PF-activated synapses according to the Vm at the time of the CF input, suggesting that the standing Vm is a critical parameter for the induction of PF synaptic plasticity. In this review, I analyse how the Vm can potentially play a role in cerebellar learning focussing, in particular, on the hyperpolarised state that appears to occur episodically, since PNs are mostly firing under physiological conditions. By revisiting the recent literature reporting in vivo recordings and synaptic plasticity studies, I speculate on how a putative role of the PN Vm can provide an interpretation for the results of these studies.
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Affiliation(s)
- Marco Canepari
- University of Grenoble Alpes, CNRS, LIPhy, F-38000, Grenoble, France. .,Laboratories of Excellence, Ion Channel Science and Therapeutics, Valbonne, France. .,Institut National de la Santé et Recherche Médicale, Paris, France.
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7
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Kim YG, Woo J, Park J, Kim S, Lee YS, Kim Y, Kim SJ. Quantitative Proteomics Reveals Distinct Molecular Signatures of Different Cerebellum-Dependent Learning Paradigms. J Proteome Res 2020; 19:2011-2025. [PMID: 32181667 DOI: 10.1021/acs.jproteome.9b00826] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The cerebellum improves motor performance by adjusting motor gain appropriately. As de novo protein synthesis is essential for the formation and retention of memories, we hypothesized that motor learning in the opposite direction would induce a distinct pattern of protein expression in the cerebellum. We conducted quantitative proteomic profiling to compare the level of protein expression in the cerebellum at 1 and 24 h after training from mice that underwent different paradigms of cerebellum-dependent oculomotor learning from specific directional changes in motor gain. We quantified a total of 43 proteins that were significantly regulated in each of the three learning paradigms in the cerebellum at 1 and 24 h after learning. In addition, functional enrichment analysis identified protein groups that were differentially enriched or depleted in the cerebellum at 24 h after the three oculomotor learnings, suggesting that distinct biological pathways may be engaged in the formation of three oculomotor memories. Weighted correlation network analysis discovered groups of proteins significantly correlated with oculomotor memory. Finally, four proteins (Snca, Sncb, Cttn, and Stmn1) from the protein group correlated with the learning amount after oculomotor training were validated by Western blot. This study provides a comprehensive and unbiased list of proteins related to three cerebellum-dependent motor learning paradigms, suggesting the distinct nature of protein expression in the cerebellum for each learning paradigm. The proteomics data have been deposited to the ProteomeXchange Consortium with identifiers <PXD008433>.
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Affiliation(s)
- Yong Gyu Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea.,Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Jongmin Woo
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea.,Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Joonho Park
- Interdisciplinary Program in Bioengineering, College of Engineering, Seoul National University, 1 Gwanak-ro, Seoul 151-742, Korea
| | - Sooyong Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea.,Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Yong-Seok Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea.,Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea.,Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Youngsoo Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea.,Interdisciplinary Program in Bioengineering, College of Engineering, Seoul National University, 1 Gwanak-ro, Seoul 151-742, Korea
| | - Sang Jeong Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea.,Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea.,Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 03080, Korea
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8
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Yang H, Yang C, Zhu Q, Wei M, Li Y, Cheng J, Liu F, Wu Y, Zhang J, Zhang C, Wu H. Rack1 Controls Parallel Fiber-Purkinje Cell Synaptogenesis and Synaptic Transmission. Front Cell Neurosci 2019; 13:539. [PMID: 31920545 PMCID: PMC6927999 DOI: 10.3389/fncel.2019.00539] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/20/2019] [Indexed: 01/01/2023] Open
Abstract
Purkinje cells (PCs) in the cerebellum receive two excitatory afferents including granule cells-derived parallel fiber (PF) and the climbing fiber. Scaffolding protein Rack1 is highly expressed in the cerebellar PCs. Here, we found delayed formation of specific cerebellar vermis lobule and impaired motor coordination in PC-specific Rack1 conditional knockout mice. Our studies further revealed that Rack1 is essential for PF–PC synapse formation. In addition, Rack1 plays a critical role in regulating synaptic plasticity and long-term depression (LTD) induction of PF–PC synapses without changing the expression of postsynaptic proteins. Together, we have discovered Rack1 as the crucial molecule that controls PF–PC synaptogenesis and synaptic plasticity. Our studies provide a novel molecular insight into the mechanisms underlying the neural development and neuroplasticity in the cerebellum.
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Affiliation(s)
- Haihong Yang
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China.,Department of Anesthesiology, The General Hospital of Western Theater Command, Chengdu, China
| | - Chaojuan Yang
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Qian Zhu
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Mengping Wei
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Ying Li
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Juanxian Cheng
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Fengjiao Liu
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Yan Wu
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Jiyan Zhang
- Department of Neuroimmunology and Antibody Engineering, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Chen Zhang
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Haitao Wu
- Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China.,Chinese Institute for Brain Research, Beijing, China.,Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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9
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Yamazaki T, Lennon W. Revisiting a theory of cerebellar cortex. Neurosci Res 2019; 148:1-8. [PMID: 30922970 DOI: 10.1016/j.neures.2019.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/14/2019] [Accepted: 03/05/2019] [Indexed: 12/22/2022]
Abstract
Long-term depression at parallel fiber-Purkinje cell synapses plays a principal role in learning in the cerebellum, which acts as a supervised learning machine. Recent experiments demonstrate various forms of synaptic plasticity at different sites within the cerebellum. In this article, we take into consideration synaptic plasticity at parallel fiber-molecular layer interneuron synapses as well as at parallel fiber-Purkinje cell synapses, and propose that the cerebellar cortex performs reinforcement learning, another form of learning that is more capable than supervised learning. We posit that through the use of reinforcement learning, the need for explicit teacher signals for learning in the cerebellum is eliminated; instead, learning can occur via responses from evaluative feedback. We demonstrate the learning capacity of cerebellar reinforcement learning using simple computer simulations of delay eyeblink conditioning and the cart-pole balancing task.
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Affiliation(s)
- Tadashi Yamazaki
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Japan.
| | - William Lennon
- Department of Electrical and Computer Engineering, University of California, San Diego, United States
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10
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Kakegawa W, Katoh A, Narumi S, Miura E, Motohashi J, Takahashi A, Kohda K, Fukazawa Y, Yuzaki M, Matsuda S. Optogenetic Control of Synaptic AMPA Receptor Endocytosis Reveals Roles of LTD in Motor Learning. Neuron 2018; 99:985-998.e6. [PMID: 30122381 DOI: 10.1016/j.neuron.2018.07.034] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 06/03/2018] [Accepted: 07/19/2018] [Indexed: 11/18/2022]
Abstract
Long-term depression (LTD) of AMPA-type glutamate receptor (AMPA receptor)-mediated synaptic transmission has been proposed as a cellular substrate for learning and memory. Although activity-induced AMPA receptor endocytosis is believed to underlie LTD, it remains largely unclear whether LTD and AMPA receptor endocytosis at specific synapses are causally linked to learning and memory in vivo. Here we developed a new optogenetic tool, termed PhotonSABER, which enabled the temporal, spatial, and cell-type-specific control of AMPA receptor endocytosis at active synapses, while the basal synaptic properties and other forms of synaptic plasticity were unaffected. We found that fiberoptic illumination to Purkinje cells expressing PhotonSABER in vivo inhibited cerebellar motor learning during adaptation of the horizontal optokinetic response and vestibulo-ocular reflex, as well as synaptic AMPA receptor decrease in the flocculus. Our results demonstrate that LTD and AMPA receptor endocytosis at specific neuronal circuits were directly responsible for motor learning in vivo. VIDEO ABSTRACT.
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Affiliation(s)
- Wataru Kakegawa
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Akira Katoh
- Department of Physiology, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Sakae Narumi
- Department of Physiology, St. Marianna University School of Medicine, Kanagawa 216-8511, Japan
| | - Eriko Miura
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Junko Motohashi
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Akiyo Takahashi
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo 182-8585, Japan
| | - Kazuhisa Kohda
- Department of Physiology, St. Marianna University School of Medicine, Kanagawa 216-8511, Japan
| | - Yugo Fukazawa
- Department of Anatomy, University of Fukui School of Medical Sciences, Fukui 910-1193, Japan
| | - Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan.
| | - Shinji Matsuda
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo 182-8585, Japan; Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan; Brain Science Inspired Life Support Research Center (BLSC), The University of Electro-Communications, Tokyo 182-8585, Japan.
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11
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Neureither F, Ziegler K, Pitzer C, Frings S, Möhrlen F. Impaired Motor Coordination and Learning in Mice Lacking Anoctamin 2 Calcium-Gated Chloride Channels. THE CEREBELLUM 2018; 16:929-937. [PMID: 28536821 PMCID: PMC5717130 DOI: 10.1007/s12311-017-0867-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Neurons communicate through excitatory and inhibitory synapses. Both lines of communication are adjustable and allow the fine tuning of signal exchange required for learning processes in neural networks. Several distinct modes of plasticity modulate glutamatergic and GABAergic synapses in Purkinje cells of the cerebellar cortex to promote motor control and learning. In the present paper, we present evidence for a role of short-term ionic plasticity in the cerebellar circuit activity. This type of plasticity results from altered chloride driving forces at the synapses that molecular layer interneurons form on Purkinje cell dendrites. Previous studies have provided evidence for transiently diminished chloride gradients at these GABAergic synapses following climbing fiber activity. Electrical stimulation of climbing fibers in acute slices caused a decline of inhibitory postsynaptic currents recorded from Purkinje cells. Dendritic calcium-gated chloride channels of the type anoctamin 2 (ANO2) were proposed to mediate this short-term modulation of inhibition, but the significance of this process for motor control has not been established yet. Here, we report results of behavioral studies obtained from Ano2−/− mice, a mouse line that was previously shown to lack this particular mode of ionic plasticity. The animals display motor coordination deficits that constitute a condition of mild ataxia. Moreover, motor learning is severely impaired in Ano2−/− mice, suggesting cerebellar dysfunction. This reduced motor performance of Ano2−/− mice highlights the significance of inhibitory control for cerebellar function and introduces calcium-dependent short-term ionic plasticity as an efficient control mechanism for neural inhibition.
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Affiliation(s)
- Franziska Neureither
- Department of Animal Molecular Physiology, Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany
| | - Katharina Ziegler
- Department of Animal Molecular Physiology, Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany
| | - Claudia Pitzer
- Interdisciplinary Neurobehavioral Core (INBC), Heidelberg University, Im Neuenheimer Feld 515, 69120, Heidelberg, Germany
| | - Stephan Frings
- Department of Animal Molecular Physiology, Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany.
| | - Frank Möhrlen
- Department of Animal Molecular Physiology, Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany
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12
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Hirano T. Regulation and Interaction of Multiple Types of Synaptic Plasticity in a Purkinje Neuron and Their Contribution to Motor Learning. THE CEREBELLUM 2018; 17:756-765. [DOI: 10.1007/s12311-018-0963-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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13
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Inoshita T, Hirano T. Occurrence of long-term depression in the cerebellar flocculus during adaptation of optokinetic response. eLife 2018; 7:36209. [PMID: 29582755 PMCID: PMC5871328 DOI: 10.7554/elife.36209] [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: 02/25/2018] [Accepted: 03/13/2018] [Indexed: 12/21/2022] Open
Abstract
Long-term depression (LTD) at parallel fiber (PF) to Purkinje cell (PC) synapses has been considered as a main cellular mechanism for motor learning. However, the necessity of LTD for motor learning was challenged by demonstration of normal motor learning in the LTD-defective animals. Here, we addressed possible involvement of LTD in motor learning by examining whether LTD occurs during motor learning in the wild-type mice. As a model of motor learning, adaptation of optokinetic response (OKR) was used. OKR is a type of reflex eye movement to suppress blur of visual image during animal motion. OKR shows adaptive change during continuous optokinetic stimulation, which is regulated by the cerebellar flocculus. After OKR adaptation, amplitudes of quantal excitatory postsynaptic currents at PF-PC synapses were decreased, and induction of LTD was suppressed in the flocculus. These results suggest that LTD occurs at PF-PC synapses during OKR adaptation.
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Affiliation(s)
- Takuma Inoshita
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Japan
| | - Tomoo Hirano
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Japan
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14
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Fang H, Wang ZH, Bu YJ, Yuan ZJ, Wang GQ, Guo Y, Cheng XY, Qiu WJ. Repeated inhalation of sevoflurane inhibits the information transmission of Purkinje cells and delays motor development via the GABAA receptor ε subunit in neonatal mice. Mol Med Rep 2017; 17:1083-1092. [PMID: 29115488 PMCID: PMC5780070 DOI: 10.3892/mmr.2017.7941] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 09/19/2017] [Indexed: 11/21/2022] Open
Abstract
General anesthesia is widely used in pediatric surgery, although the influence of general anesthesia on cerebellar information transmission and motor function is unclear. In the present study, neonatal mice received repeated inhalation of sevoflurane, and electrophysiological alterations in Purkinje cells (PCs) and the development of motor functions were detected. In addition, γ-aminobutyric acidA receptor ε (GABAA-R ε) subunit knockout mice were used to investigate the mechanism of action of sevoflurane on cerebellar function. In the neonatal mice, the field potential response of PCs induced by sensory stimulation and the motor function indices were markedly inhibited by sevoflurane, and the inhibitory effect was positively associated with the number of repetitions of anesthesia. In additional the GABAA-R ε subunit level of PCs was promoted by sevoflurane in a dose-dependent manner, and the inhibitory effects of sevoflurane on PC field potential response and motor function were alleviated in GABAA-R ε subunit knockout mice. The GABAA-R ε subunit was activated by sevoflurane, leading to inhibition of sensory information transmission in the cerebellar cortex, field potential responses of PCs and the development of cerebellar motor function. The present study provided experimental evidence for the safe usage of sevoflurane in clinical anesthesia, and suggested that GABAA-R ε subunit antagonists may be considered for combined application with general anesthesia with repeated inhalation of sevoflurane, for adverse effect prevention in the clinic.
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Affiliation(s)
- Hong Fang
- Department of Anesthesiology, The Affiliated Heji Hospital of Changzhi Medical College, Changzhi, Shanxi 046011, P.R. China
| | - Ze-Hua Wang
- Department of Anesthesiology, The Affiliated Heji Hospital of Changzhi Medical College, Changzhi, Shanxi 046011, P.R. China
| | - Ying-Jiang Bu
- Department of Anesthesiology, The Affiliated Heji Hospital of Changzhi Medical College, Changzhi, Shanxi 046011, P.R. China
| | - Zhi-Jun Yuan
- Department of Anesthesiology, The Affiliated Heji Hospital of Changzhi Medical College, Changzhi, Shanxi 046011, P.R. China
| | - Guo-Qiang Wang
- Department of Anesthesiology, The Affiliated Heji Hospital of Changzhi Medical College, Changzhi, Shanxi 046011, P.R. China
| | - Yan Guo
- Department of Anesthesiology, The Affiliated Heji Hospital of Changzhi Medical College, Changzhi, Shanxi 046011, P.R. China
| | - Xiao-Yun Cheng
- Department of Anesthesiology, The Suburban People's Hospital, Changzhi, Shanxi 046011, P.R. China
| | - Wen-Jie Qiu
- Department of Anesthesiology, The Suburban People's Hospital, Changzhi, Shanxi 046011, P.R. China
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15
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Nitta K, Matsuzaki Y, Konno A, Hirai H. Minimal Purkinje Cell-Specific PCP2/L7 Promoter Virally Available for Rodents and Non-human Primates. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 6:159-170. [PMID: 28828391 PMCID: PMC5552061 DOI: 10.1016/j.omtm.2017.07.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 07/24/2017] [Indexed: 01/10/2023]
Abstract
Cell-type-specific promoters in combination with viral vectors and gene-editing technology permit efficient gene manipulation in specific cell populations. Cerebellar Purkinje cells play a pivotal role in cerebellar functions. Although the Purkinje cell-specific L7 promoter is widely used for the generation of transgenic mice, it remains unsuitable for viral vectors because of its large size (3 kb) and exceedingly weak promoter activity. Here, we found that the 0.8-kb region (named here as L7-6) upstream of the transcription initiation codon in the first exon was alone sufficient as a Purkinje cell-specific promoter, presenting a far stronger promoter activity over the original 3-kb L7 promoter with a sustained significant specificity to Purkinje cells. Intravenous injection of adeno-associated virus vectors that are highly permeable to the blood-brain barrier confirmed the Purkinje cell specificity of the L7-6 in the CNS. The features of the L7-6 were also preserved in the marmoset, a non-human primate. The high sequence homology of the L7-6 among mouse, marmoset, and human suggests the preservation of the promoter strength and Purkinje cell specificity features also in humans. These findings suggest that L7-6 will facilitate the cerebellar research targeting the pathophysiology and gene therapy of cerebellar disorders.
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Affiliation(s)
- Keisuke Nitta
- Department of Neurophysiology & Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan.,Department of Ophthalmology, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
| | - Yasunori Matsuzaki
- Department of Neurophysiology & Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
| | - Ayumu Konno
- Department of Neurophysiology & Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
| | - Hirokazu Hirai
- Department of Neurophysiology & Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan.,Research Program for Neural Signalling, Division of Endocrinology, Metabolism and Signal Research, Gunma University Initiative for Advanced Research, Maebashi, Gunma 371-8511, Japan
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16
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Differential regulations of vestibulo-ocular reflex and optokinetic response by β- and α2-adrenergic receptors in the cerebellar flocculus. Sci Rep 2017. [PMID: 28638085 PMCID: PMC5479797 DOI: 10.1038/s41598-017-04273-9] [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] [Indexed: 12/28/2022] Open
Abstract
Norepinephrine modulates synaptic plasticity in various brain regions and is implicated in memory formation, consolidation and retrieval. The cerebellum is involved in motor learning, and adaptations of the vestibulo-ocular reflex (VOR) and optokinetic response (OKR) have been studied as models of cerebellum-dependent motor learning. Previous studies showed the involvement of adrenergic systems in the regulation of VOR, OKR and cerebellar synaptic functions. Here, we show differential contributions of β- and α2-adrenergic receptors in the mouse cerebellar flocculus to VOR and OKR control. Effects of application of β- or α2-adrenergic agonist or antagonist into the flocculus suggest that the β-adrenergic receptor activity maintains the VOR gain at high levels and contributes to adaptation of OKR, and that α2-adrenergic receptor counteracts the β-receptor activity in VOR and OKR control. We also examined effects of norepinephrine application, and the results suggest that norepinephrine regulates VOR and OKR through β-adrenergic receptor at low concentrations and through α2-receptor at high concentrations.
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17
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Abstract
The mechanism by which a learnt synaptic weight change can contribute to learning or adaptation of brain function is a type of credit assignment problem, which is a key issue for many parts of the brain. In the cerebellum, detailed knowledge not only of the local circuitry connectivity but also of the topography of different sources of afferent/external information makes this problem particularly tractable. In addition, multiple forms of synaptic plasticity and their general rules of induction have been identified. In this review, we will discuss the possible roles of synaptic and cellular plasticity at specific locations in contributing to behavioral changes. Focus will be on the parts of the cerebellum that are devoted to limb control, which constitute a large proportion of the cortex and where the knowledge of the external connectivity is particularly well known. From this perspective, a number of sites of synaptic plasticity appear to primarily have the function of balancing the overall level of activity in the cerebellar circuitry, whereas the locations at which synaptic plasticity leads to functional changes in terms of limb control are more limited. Specifically, the postsynaptic forms of long-term potentiation (LTP) and long-term depression (LTD) at the parallel fiber synapses made on interneurons and Purkinje cells, respectively, are the types of plasticity that mediate the widest associative capacity and the tightest link between the synaptic change and the external functions that are to be controlled.
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Affiliation(s)
- Henrik Jörntell
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, Lund, Sweden.
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18
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Jörntell H. Cerebellar physiology: links between microcircuitry properties and sensorimotor functions. J Physiol 2016; 595:11-27. [PMID: 27388692 DOI: 10.1113/jp272769] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/29/2016] [Indexed: 11/08/2022] Open
Abstract
Existing knowledge of the cerebellar microcircuitry structure and physiology allows a rather detailed description of what it in itself can and cannot do. Combined with a known mapping of different cerebellar regions to afferent systems and motor output target structures, there are several constraints that can be used to describe how specific components of the cerebellar microcircuitry may work during sensorimotor control. In fact, as described in this review, the major factor that hampers further progress in understanding cerebellar function is the limited insights into the circuitry-level function of the targeted motor output systems and the nature of the information in the mossy fiber afferents. The cerebellar circuitry in itself is here summarized as a gigantic associative memory element, primarily consisting of the parallel fiber synapses, whereas most other circuitry components, including the climbing fiber system, primarily has the role of maintaining activity balance in the intracerebellar and extracerebellar circuitry. The review explores the consistency of this novel interpretational framework with multiple diverse observations at the synaptic and microcircuitry level within the cerebellum.
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Affiliation(s)
- Henrik Jörntell
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, Sweden
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19
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Ramakrishnan KB, Voges K, De Propris L, De Zeeuw CI, D'Angelo E. Tactile Stimulation Evokes Long-Lasting Potentiation of Purkinje Cell Discharge In Vivo. Front Cell Neurosci 2016; 10:36. [PMID: 26924961 PMCID: PMC4757673 DOI: 10.3389/fncel.2016.00036] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 02/01/2016] [Indexed: 12/02/2022] Open
Abstract
In the cerebellar network, a precise relationship between plasticity and neuronal discharge has been predicted. However, the potential generation of persistent changes in Purkinje cell (PC) spike discharge as a consequence of plasticity following natural stimulation patterns has not been clearly determined. Here, we show that facial tactile stimuli organized in theta-patterns can induce stereotyped N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA-A) receptor-dependent changes in PCs and molecular layer interneurons (MLIs) firing: invariably, all PCs showed a long-lasting increase (Spike-Related Potentiation or SR-P) and MLIs a long-lasting decrease (Spike-Related Suppression or SR-S) in baseline activity and spike response probability. These observations suggests that tactile sensory stimulation engages multiple long-term plastic changes that are distributed along the mossy fiber-parallel fiber (MF-PF) pathway and operate synergistically to potentiate spike generation in PCs. In contrast, theta-pattern electrical stimulation (ES) of PFs indistinctly induced SR-P and SR-S both in PCs and MLIs, suggesting that tactile sensory stimulation preordinates plasticity upstream of the PF-PC synapse. All these effects occurred in the absence of complex spike changes, supporting the theoretical prediction that PC activity is potentiated when the MF-PF system is activated in the absence of conjunctive climbing fiber (CF) activity.
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Affiliation(s)
- K B Ramakrishnan
- Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy; Consorzio Interuniversitario per le Scienze Fisiche della Materia (CNISM)Pavia, Italy
| | - Kai Voges
- Department of Neuroscience, Erasmus University Rotterdam Rotterdam, Netherlands
| | - Licia De Propris
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy
| | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus University RotterdamRotterdam, Netherlands; Netherlands Institute for Neuroscience, Royal Academy of Arts and SciencesAmsterdam, Netherlands
| | - Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy; Brain Connectivity Center, Istituto Neurologico IRCCS Fondazione C. MondinoPavia, Italy
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20
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Nakamura Y, Hirano T. Intracellular Ca(2+) thresholds for induction of excitatory long-term depression and inhibitory long-term potentiation in a cerebellar Purkinje neuron. Biochem Biophys Res Commun 2015; 469:803-8. [PMID: 26707644 DOI: 10.1016/j.bbrc.2015.12.065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 12/16/2015] [Indexed: 12/31/2022]
Abstract
Synaptic plasticity in the cerebellar cortex contributes to motor learning. In particular, long-term depression at excitatory parallel fiber - Purkinje neuron synapses has been intensively studied as a primary cellular mechanism for motor learning. Recent studies showed that synaptic plasticity other than long-term depression such as long-term potentiation at inhibitory interneuron - Purkinje neuron synapses called rebound potentiation is also involved in motor learning. It was suggested that long-term depression and rebound potentiation might synergistically support motor learning. Here, we have examined induction conditions of long-term depression and rebound potentiation in cultured rat Purkinje neurons, and found that both of them were induced simultaneously by certain patterns of depolarization of a Purkinje neuron. Further, we found that long-term depression was induced by shorter depolarizing pulses causing a smaller intracellular Ca(2+) increase than rebound potentiation. These results support an idea that long-term depression and rebound potentiation synergistically contribute to motor learning, and suggest that long-term depression may play a primary role in wider variety of motor learning paradigms than rebound potentiation.
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Affiliation(s)
- Yoji Nakamura
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Tomoo Hirano
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
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21
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22
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Gaffield MA, Amat SB, Bito H, Christie JM. Chronic imaging of movement-related Purkinje cell calcium activity in awake behaving mice. J Neurophysiol 2015; 115:413-22. [PMID: 26561609 DOI: 10.1152/jn.00834.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/05/2015] [Indexed: 01/28/2023] Open
Abstract
Purkinje cells (PCs) are a major site of information integration and plasticity in the cerebellum, a brain region involved in motor task refinement. Thus PCs provide an ideal location for studying the mechanisms necessary for cerebellum-dependent motor learning. Increasingly, sophisticated behavior tasks, used in combination with genetic reporters and effectors of activity, have opened up the possibility of studying cerebellar circuits during voluntary movement at an unprecedented level of quantitation. However, current methods used to monitor PC activity do not take full advantage of these advances. For example, single-unit or multiunit electrode recordings, which provide excellent temporal information regarding electrical activity, only monitor a small population of cells and can be quite invasive. Bolus loading of cell-permeant calcium (Ca(2+)) indicators is short-lived, requiring same-day imaging immediately after surgery and/or indicator injection. Genetically encoded Ca(2+) indicators (GECIs) overcome many of these limits and have garnered considerable use in many neuron types but only limited use in PCs. Here we employed these indicators to monitor Ca(2+) activity in PCs over several weeks. We could repeatedly image from the same cerebellar regions across multiple days and observed stable activity. We used chronic imaging to monitor PC activity in crus II, an area previously linked to licking behavior, and identified a region of increased activity at the onset of licking. We then monitored this same region after training tasks to initiate voluntary licking behavior in response to different sensory stimuli. In all cases, PC Ca(2+) activity increased at the onset of rhythmic licking.
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Affiliation(s)
| | - Samantha B Amat
- Max Planck Florida Institute for Neuroscience, Jupiter, Florida; and
| | - Haruhiko Bito
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Jason M Christie
- Max Planck Florida Institute for Neuroscience, Jupiter, Florida; and
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23
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Abstract
Although our ability to store semantic declarative information can nowadays be readily surpassed by that of simple personal computers, our ability to learn and express procedural memories still outperforms that of supercomputers controlling the most advanced robots. To a large extent, our procedural memories are formed in the cerebellum, which embodies more than two-thirds of all neurons in our brain. In this review, we will focus on the emerging view that different modules of the cerebellum use different encoding schemes to form and express their respective memories. More specifically, zebrin-positive zones in the cerebellum, such as those controlling adaptation of the vestibulo-ocular reflex, appear to predominantly form their memories by potentiation mechanisms and express their memories via rate coding, whereas zebrin-negative zones, such as those controlling eyeblink conditioning, appear to predominantly form their memories by suppression mechanisms and express their memories in part by temporal coding using rebound bursting. Together, the different types of modules offer a rich repertoire to acquire and control sensorimotor processes with specific challenges in the spatiotemporal domain.
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Affiliation(s)
- Chris I De Zeeuw
- Department of Neuroscience, Erasmus Medical Center, 3015 GE Rotterdam, The Netherlands Netherlands Institute for Neuroscience, 1105 BA Amsterdam, The Netherlands
| | - Michiel M Ten Brinke
- Department of Neuroscience, Erasmus Medical Center, 3015 GE Rotterdam, The Netherlands
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24
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25
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Psychophysical testing in rodent models of glaucomatous optic neuropathy. Exp Eye Res 2015; 141:154-63. [PMID: 26144667 DOI: 10.1016/j.exer.2015.06.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 06/08/2015] [Accepted: 06/29/2015] [Indexed: 12/14/2022]
Abstract
Processing of visual information begins in the retina, with photoreceptors converting light stimuli into neural signals. Ultimately, signals are transmitted to the brain through signaling networks formed by interneurons, namely bipolar, horizontal and amacrine cells providing input to retinal ganglion cells (RGCs), which form the optic nerve with their axons. As part of the chronic nature of glaucomatous optic neuropathy, the increasing and irreversible damage and ultimately loss of neurons, RGCs in particular, occurs following progressive damage to the optic nerve head (ONH), eventually resulting in visual impairment and visual field loss. There are two behavioral assays that are typically used to assess visual deficits in glaucoma rodent models, the visual water task and the optokinetic drum. The visual water task can assess an animal's ability to distinguish grating patterns that are associated with an escape from water. The optokinetic drum relies on the optomotor response, a reflex turning of the head and neck in the direction of the visual stimuli, which usually consists of rotating black and white gratings. This reflex is a physiological response critical for keeping the image stable on the retina. Driven initially by the neuronal input from direction-selective RGCs, this reflex is comprised of a number of critical sensory and motor elements. In the presence of repeatable and defined stimuli, this reflex is extremely well suited to analyze subtle changes in the circuitry and performance of retinal neurons. Increasing the cycles of these alternating gratings per degree, or gradually reducing the contrast of the visual stimuli, threshold levels can be determined at which the animal is no longer tracking the stimuli, and thereby visual function of the animal can be determined non-invasively. Integrating these assays into an array of outcome measures that determine multiple aspects of visual function is a central goal in vision research and can be realized, for example, by the combination of measuring optomotor reflex function with electroretinograms (ERGs) and optical coherence tomography (OCT) of the retina. These structure-function correlations in vivo are urgently needed to identify disease mechanisms as potential new targets for drug development. Such a combination of the experimental assessment of the optokinetic reflex (OKR) or optomotor response (OMR) with other measures of retinal structure and function is especially valuable for research on GON. The chronic progression of the disease is characterized by a gradual decrease in function accompanied by a concomitant increase in structural damage to the retina, therefore the assessment of subtle changes is key to determining the success of novel intervention strategies.
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26
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Bing YH, Wu MC, Chu CP, Qiu DL. Facial stimulation induces long-term depression at cerebellar molecular layer interneuron-Purkinje cell synapses in vivo in mice. Front Cell Neurosci 2015; 9:214. [PMID: 26106296 PMCID: PMC4460530 DOI: 10.3389/fncel.2015.00214] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/20/2015] [Indexed: 12/03/2022] Open
Abstract
Cerebellar long-term synaptic plasticity has been proposed to provide a cellular mechanism for motor learning. Numerous studies have demonstrated the induction and mechanisms of synaptic plasticity at parallel fiber–Purkinje cell (PF–PC), parallel fiber–molecular layer interneurons (PF–MLI) and mossy fiber–granule cell (MF–GC) synapses, but no study has investigated sensory stimulation-evoked synaptic plasticity at MLI–PC synapses in the cerebellar cortex of living animals. We studied the expression and mechanism of MLI–PC GABAergic synaptic plasticity induced by a train of facial stimulation in urethane-anesthetized mice by cell-attached recordings and pharmacological methods. We found that 1 Hz, but not a 2 Hz or 4 Hz, facial stimulation induced a long-term depression (LTD) of GABAergic transmission at MLI–PC synapses, which was accompanied with a decrease in the stimulation-evoked pause of spike firing in PCs, but did not induce a significant change in the properties of the sensory-evoked spike events of MLIs. The MLI–PC GABAergic LTD could be prevented by blocking cannabinoid type 1 (CB1) receptors, and could be pharmacologically induced by a CB1 receptor agonist. Additionally, 1 Hz facial stimulation delivered in the presence of a metabotropic glutamate receptor 1 (mGluR1) antagonist, JNJ16259685, still induced the MLI–PC GABAergic LTD, whereas blocking N-methyl-D-aspartate (NMDA) receptors during 1 Hz facial stimulation abolished the expression of MLI–PC GABAergic LTD. These results indicate that sensory stimulation can induce an endocannabinoid (eCB)-dependent LTD of GABAergic transmission at MLI–PC synapses via activation of NMDA receptors in cerebellar cortical Crus II in vivo in mice. Our results suggest that the sensory stimulation-evoked MLI–PC GABAergic synaptic plasticity may play a critical role in motor learning in animals.
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Affiliation(s)
- Yan-Hua Bing
- Cellular Function Research Center, Yanbian University Yanji, Jilin Province, China ; Department of Physiology and Pathophysiology, College of Medicine, Yanbian University Yanji, Jilin Province, China
| | - Mao-Cheng Wu
- Cellular Function Research Center, Yanbian University Yanji, Jilin Province, China ; Department of Osteology, Affiliated Hospital of Yanbian University Yanji, Jilin Province, China
| | - Chun-Ping Chu
- Cellular Function Research Center, Yanbian University Yanji, Jilin Province, China
| | - De-Lai Qiu
- Cellular Function Research Center, Yanbian University Yanji, Jilin Province, China ; Department of Physiology and Pathophysiology, College of Medicine, Yanbian University Yanji, Jilin Province, China
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27
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Abstract
Long-term depression (LTD) at parallel fiber-Purkinje neuron synapses has been regarded as a primary cellular mechanism for motor learning. However, this hypothesis has been challenged. Demonstration of normal motor learning under LTD-suppressed conditions suggested that motor learning can occur without LTD. Synaptic plasticity mechanisms other than LTD have been found at various synapses in the cerebellum. Animals may achieve motor learning using several types of synaptic plasticity in the cerebellum including LTD.
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28
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Mansouri M, Kasugai Y, Fukazawa Y, Bertaso F, Raynaud F, Perroy J, Fagni L, Kaufmann WA, Watanabe M, Shigemoto R, Ferraguti F. Distinct subsynaptic localization of type 1 metabotropic glutamate receptors at glutamatergic and
GABA
ergic synapses in the rodent cerebellar cortex. Eur J Neurosci 2014; 41:157-67. [DOI: 10.1111/ejn.12779] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 09/26/2014] [Accepted: 10/05/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Mahnaz Mansouri
- Department of Pharmacology Innsbruck Medical University Innsbruck Austria
| | - Yu Kasugai
- Department of Pharmacology Innsbruck Medical University Innsbruck Austria
| | - Yugo Fukazawa
- Division of Cerebral Structure National Institute for Physiological Sciences Okazaki Japan
| | - Federica Bertaso
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Fabrice Raynaud
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Julie Perroy
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Laurent Fagni
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Walter A. Kaufmann
- Department of Pharmacology Innsbruck Medical University Innsbruck Austria
| | | | - Ryuichi Shigemoto
- Division of Cerebral Structure National Institute for Physiological Sciences Okazaki Japan
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Nagasaki N, Hirano T, Kawaguchi SY. Opposite regulation of inhibitory synaptic plasticity by α and β subunits of Ca(2+)/calmodulin-dependent protein kinase II. J Physiol 2014; 592:4891-909. [PMID: 25217378 DOI: 10.1113/jphysiol.2014.280230] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Induction of several forms of synaptic plasticity, a cellular basis for learning and memory, depends on the activation of Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII). CaMKII acts as a holoenzyme consisting of α and β subunits (α- and βCaMKII). However, it remains elusive how the subunit composition of a CaMKII holoenzyme affects its activation and hence synaptic plasticity. We addressed this issue by focusing on long-term potentiation (LTP) at inhibitory synapses on cerebellar Purkinje neurons (PNs) (called rebound potentiation, RP). The contribution of each subunit to RP was examined by selective knock-down or overexpression of that subunit. Electrophysiological recording from a rat cultured PN demonstrated that βCaMKII is essential for RP induction, whereas αCaMKII suppresses it. Thus, RP was negatively regulated due to the greater relative abundance of αCaMKII compared to βCaMKII, suggesting a critical role of CaMKII subunit composition in RP. The higher affinity of βCaMKII to Ca(2+)/CaM compared with αCaMKII was responsible for the predominant role in RP induction. Live-cell imaging of CaMKII activity based on the Förster resonance energy transfer (FRET) technique revealed that βCaMKII enrichment enhances the total CaMKII activation upon a transient conditioning depolarization. Taken together, these findings clarified that α- and βCaMKII oppositely regulate CaMKII activation, controlling the induction of inhibitory synaptic plasticity in a PN, which might contribute to the adaptive information processing of the cerebellar cortex.
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Affiliation(s)
- Nobuhiro Nagasaki
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Tomoo Hirano
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Shin-ya Kawaguchi
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan Graduate School of Brain Science, Doshisha University, Kizugawa-shi, Kyoto, 619-0025, Japan
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30
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Abstract
Cerebellar climbing fiber activity encodes performance errors during many motor learning tasks, but the role of these error signals in learning has been controversial. We compared two motor learning paradigms that elicited equally robust putative error signals in the same climbing fibers: learned increases and decreases in the gain of the vestibulo-ocular reflex (VOR). During VOR-increase training, climbing fiber activity on one trial predicted changes in cerebellar output on the next trial, and optogenetic activation of climbing fibers to mimic their encoding of performance errors was sufficient to implant a motor memory. In contrast, during VOR-decrease training, there was no trial-by-trial correlation between climbing fiber activity and changes in cerebellar output, and climbing fiber activation did not induce VOR-decrease learning. Our data suggest that the ability of climbing fibers to induce plasticity can be dynamically gated in vivo, even under conditions where climbing fibers are robustly activated by performance errors. DOI:http://dx.doi.org/10.7554/eLife.02076.001 The cerebellum (or ‘little brain’) is located underneath the cerebral hemispheres. Despite comprising around 10% of the brain’s volume, the cerebellum contains roughly half of the brain’s neurons. Many of the functions of the cerebellum are related to the control and fine-tuning of movement, and people whose cerebellum has been damaged have problems with balance and coordination, and with learning new motor skills. One of the roles of the cerebellum is to control a reflex known as the vestibulo-ocular reflex, which enables us to keep our gaze fixed on an object as we turn our heads. The cerebellum relays information about head movements to the muscles that control the eyes, instructing the eyes to move in the opposite direction to the head. This keeps the image of the object we are looking at stable on the retina. The vestibulo-ocular reflex is controlled by a circuit that includes Purkinje cells (which are the main output cells of the cerebellum) and climbing fibres (which originate in the brainstem). Any failure of the vestibulo-ocular reflex to fully compensate for head movements generates an error signal that activates the climbing fibres. These in turn modify the output of Purkinje cells, leading ultimately to adjustments in eye movements. However, Kimpo et al. have now obtained evidence that Purkinje cells can modulate their response to the instructions they receive from climbing fibres. Monkeys sat in a rotating chair while a visual object they were trained to track with their eyes was moved to induce errors in the vestibulo-ocular reflex. When the object was moved so that a bigger reflexive eye movement was required to stabilize the image, the activation of the climbing fibres in response to the error led to a change in the response of the Purkinje cells, as expected. However, when a smaller reflexive eye movement was needed, the error-driven responses of the climbing fibres did not alter the responses of Purkinje cells. Similar results were obtained using pulses of light to artificially activate climbing fibres and thus simulate error signals. The work of Kimpo et al. indicates that the cerebellum does not blindly follow the instructions it receives from the brainstem, but can instead modulate its responses to incoming information about performance errors. Further work is now required to identify factors that influence the responsiveness of the cerebellum: such information could ultimately be used to improve learning of motor skills and recovery from injury. DOI:http://dx.doi.org/10.7554/eLife.02076.002
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Affiliation(s)
- Rhea R Kimpo
- Department of Neurobiology, Stanford University, Stanford, United States
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31
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Hawkes R. Purkinje cell stripes and long-term depression at the parallel fiber-Purkinje cell synapse. Front Syst Neurosci 2014; 8:41. [PMID: 24734006 PMCID: PMC3975104 DOI: 10.3389/fnsys.2014.00041] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/07/2014] [Indexed: 12/13/2022] Open
Abstract
The cerebellar cortex comprises a stereotyped array of transverse zones and parasagittal stripes, built around multiple Purkinje cell subtypes, which is highly conserved across birds and mammals. This architecture is revealed in the restricted expression patterns of numerous molecules, in the terminal fields of the afferent projections, in the distribution of interneurons, and in the functional organization. This review provides an overview of cerebellar architecture with an emphasis on attempts to relate molecular architecture to the expression of long-term depression (LTD) at the parallel fiber-Purkinje cell (pf-PC) synapse.
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Affiliation(s)
- Richard Hawkes
- Department of Cell Biology and Anatomy, University of Calgary Calgary, AB, Canada ; Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada ; Genes and Development Research Group, Faculty of Medicine, University of Calgary Calgary, AB, Canada
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32
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Fritschy JM, Panzanelli P. GABAAreceptors and plasticity of inhibitory neurotransmission in the central nervous system. Eur J Neurosci 2014; 39:1845-65. [DOI: 10.1111/ejn.12534] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Revised: 01/29/2014] [Accepted: 01/29/2014] [Indexed: 12/11/2022]
Affiliation(s)
- Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology; University of Zurich; Winterthurerstrasse 190 8057 Zurich Switzerland
- Neuroscience Center Zurich; University of Zurich and ETH; Zurich Switzerland
| | - Patrizia Panzanelli
- Department of Neuroscience Rita Levi Montalcini; University of Turin; Turin Italy
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33
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Hirano T, Kawaguchi SY. Regulation and functional roles of rebound potentiation at cerebellar stellate cell-Purkinje cell synapses. Front Cell Neurosci 2014; 8:42. [PMID: 24600347 PMCID: PMC3927423 DOI: 10.3389/fncel.2014.00042] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 01/29/2014] [Indexed: 11/13/2022] Open
Abstract
Purkinje cells receive both excitatory and inhibitory synaptic inputs and send sole output from the cerebellar cortex. Long-term depression (LTD), a type of synaptic plasticity, at excitatory parallel fiber-Purkinje cell synapses has been studied extensively as a primary cellular mechanism of motor learning. On the other hand, at inhibitory synapses on a Purkinje cell, postsynaptic depolarization induces long-lasting potentiation of GABAergic synaptic transmission. This synaptic plasticity is called rebound potentiation (RP), and its molecular regulatory mechanisms have been studied. The increase in intracellular Ca(2+) concentration caused by depolarization induces RP through enhancement of GABAA receptor (GABAAR) responsiveness. RP induction depends on binding of GABAAR with GABAAR associated protein (GABARAP) which is regulated by Ca(2+)/calmodulin-dependent kinase II (CaMKII). Whether RP is induced or not is determined by the balance between phosphorylation and de-phosphorylation activities regulated by intracellular Ca(2+) and by metabotropic GABA and glutamate receptors. Recent studies have revealed that the subunit composition of CaMKII has significant impact on RP induction. A Purkinje cell expresses both α- and β-CaMKII, and the latter has much higher affinity for Ca(2+)/calmodulin than the former. It was shown that when the relative amount of α- to β-CaMKII is large, RP induction is suppressed. The functional significance of RP has also been studied using transgenic mice in which a peptide inhibiting association of GABARAP and GABAAR is expressed selectively in Purkinje cells. The transgenic mice show abrogation of RP and subnormal adaptation of vestibulo-ocular reflex (VOR), a type of motor learning. Thus, RP is involved in a certain type of motor learning.
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Affiliation(s)
- Tomoo Hirano
- Department of Biophysics, Graduate School of Science, Kyoto University Kitashirakawa-Oiwake-cho Kyoto, Japan
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34
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Gao Z, van Woerden GM, Elgersma Y, De Zeeuw CI, Hoebeek FE. Distinct roles of α- and βCaMKII in controlling long-term potentiation of GABAA-receptor mediated transmission in murine Purkinje cells. Front Cell Neurosci 2014; 8:16. [PMID: 24550776 PMCID: PMC3910348 DOI: 10.3389/fncel.2014.00016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/10/2014] [Indexed: 01/20/2023] Open
Abstract
Calcium/Calmodulin-dependent kinase type II (CaMKII) is essential for various forms of synaptic plasticity. The predominant α- and βCaMKII isoforms have both been shown to contribute to specific forms of plasticity at excitatory synapses, but little is known about their functions at inhibitory synapses. Here we investigated the role of both isoforms in long-term potentiation of the inhibitory molecular layer interneuron to Purkinje cell synapse (MLI-PC iLTP) upon climbing fiber (CF) stimulation. We demonstrate that deleting either the α- or βCaMKII isoform affected MLI-PC iLTP. In the presence of the PP2B blocker cyclosporin A, CF stimulation elicited iLTP in Camk2b-/- mice, but not in Camk2a-/- mice. Moreover, co-activation of the MLIs and CF suppressed iLTP in wild-type mice through activation of GABAB-receptors, whereas it evoked iLTP in Camk2b-/-. This reversal of the effect of αCaMKII activity in Camk2b-/- mutants upon co-activation did not critically involve protein kinase A, but depended on calcium release from internal stores. Our results indicate that α- and βCaMKII isoforms in Purkinje cells can be differentially activated and serve distinct roles in controlling iLTP. We propose that the CaMKII holo-enzyme may be selectively activated by various GABAB-mediated pathways and that the presence of the βCaMKII isoform determines their impact on inhibitory plasticity.
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Affiliation(s)
- Zhenyu Gao
- Department of Neuroscience, Erasmus Medical Centre Rotterdam, Netherlands
| | | | - Ype Elgersma
- Department of Neuroscience, Erasmus Medical Centre Rotterdam, Netherlands
| | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus Medical Centre Rotterdam, Netherlands ; Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences Amsterdam, Netherlands
| | - Freek E Hoebeek
- Department of Neuroscience, Erasmus Medical Centre Rotterdam, Netherlands
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