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Lalonde R, Strazielle C. The Neuroanatomical Basis of the 5-HT Syndrome and Harmalineinduced Tremor. Curr Rev Clin Exp Pharmacol 2024; 19:163-172. [PMID: 37403385 DOI: 10.2174/2772432819666230703095203] [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] [Received: 12/04/2022] [Revised: 05/16/2023] [Accepted: 05/31/2023] [Indexed: 07/06/2023]
Abstract
The 5-HT syndrome in rats is composed of head weaving, body shaking, forepaw treading, flat body posture, hindlimb abduction, and Straub tail. The importance of the brainstem and spinal cord for the syndrome is underlined by findings of 5,7-dihydroxytryptamine (5,7-DHT)-induced denervation supersensitivity in response to 5-HT-stimulant drugs. For head weaving and Straub tail, supersensitivity occurred when the neurotoxin was injected into the cisterna magna or spinal cord, for forepaw treading in cisterna magna, and for hindlimb abduction in the spinal cord. Although 5,7- DHT-related body shaking increased in the spinal cord, the sign decreased when injected into the striatum, indicating the modulatory influence of the basal ganglia. Further details on body shaking are provided by its reduced response to harmaline after 5-HT depletion caused by intraventricular 5,7-DHT, electrolytic lesions of the medial or dorsal raphe, and lesions of the inferior olive caused by systemic injection of 3-acetylpyridine along with those found in Agtpbp1pcd or nr cerebellar mouse mutants. Yet the influence of the climbing fiber pathway on other signs of the 5-HT syndrome remains to be determined.
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Affiliation(s)
- Robert Lalonde
- University of Lorraine, Laboratory of Stress, Immunity, Pathogens (EA7300), Medical School, 54500 Vandoeuvre-les- Nancy, France
| | - Catherine Strazielle
- University of Lorraine, Laboratory of Stress, Immunity, Pathogens (EA7300), Medical School, 54500 Vandoeuvre-les- Nancy, France
- Dépt Médecine, Centre Hospitalier Universitaire de Nancy, Vandoeuvre-les-Nancy, France
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Kuo SH, Louis ED. How important is the inferior olive in essential tremor? An evolving story. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:129-132. [PMID: 36172066 PMCID: PMC9512123 DOI: 10.1016/s0074-7742(22)00055-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Affiliation(s)
- Sheng-Han Kuo
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, United States
- Initiative for Columbia Ataxia and Tremor, Columbia University, New York, NY, United States
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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Bello EM, Blumenfeld M, Dao J, Krieg JDS, Wilmerding LK, Johnson MD. Considerations Using Harmaline for a Primate Model of Tremor. Tremor Other Hyperkinet Mov (N Y) 2021; 11:35. [PMID: 34611499 PMCID: PMC8447964 DOI: 10.5334/tohm.634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/25/2021] [Indexed: 11/20/2022] Open
Abstract
Background While harmaline has been used as a pharmacological model of essential tremor (ET) in rodents and pigs, less is known about the effects of this pharmacological treatment in awake-behaving non-human primates. In this study, we investigated the time-course, amplitude, frequency, and consistency of harmaline tremor in primates. Methods Three rhesus macaques were administered doses of harmaline ranging from 2-12 mg/kg (i.m.), and tremorous movements were quantified with accelerometers. One subject was also trained to perform a self-paced cued reaching task, with task engagement assessed under harmaline doses ranging from 2-8 mg/kg (i.m.). Results Whole-body tremors manifested within 30 minutes of threshold-dose administration, and peak oscillatory frequency ranged between 10-14 Hz. However, large differences in tremor intensity and intermittency were observed across individual subjects under similar dosing levels. Additionally, engagement with the reaching task was dependent on harmaline dose, with performance mostly unaffected at 2 mg/kg and with little task-engagement at 8 mg/kg. Discussion We provide a detailed assessment of factors that may underlie the heterogeneous responses to harmaline, and lay out important caveats towards the applicability of the behaving harmaline-tremoring non-human primate as a preclinical model for ET. Highlights The harmaline-primate is revisited for its potential as a preclinical model of tremor. Spontaneous tremor was heterogenous in amplitude across subjects despite similar harmaline doses, action tremors were not consistently observed, and performance on a behavioral task degraded with higher dosages.
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Affiliation(s)
- Edward M. Bello
- Biomedical Engineering Department, University of Minnesota, US
| | | | - Joan Dao
- Biomedical Engineering Department, University of Minnesota, US
| | | | | | - Matthew D. Johnson
- Biomedical Engineering Department, University of Minnesota, US
- Institute for Translational Neuroscience, University of Minnesota, US
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Kakei S, Manto M, Tanaka H, Mitoma H. Pathophysiology of Cerebellar Tremor: The Forward Model-Related Tremor and the Inferior Olive Oscillation-Related Tremor. Front Neurol 2021; 12:694653. [PMID: 34262527 PMCID: PMC8273235 DOI: 10.3389/fneur.2021.694653] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 05/18/2021] [Indexed: 01/14/2023] Open
Abstract
Lesions in the Guillain-Mollaret (G-M) triangle frequently cause various types of tremors or tremor-like movements. Nevertheless, we know relatively little about their generation mechanisms. The deep cerebellar nuclei (DCN), which is a primary node of the triangle, has two main output paths: the primary excitatory path to the thalamus, the red nucleus (RN), and other brain stem nuclei, and the secondary inhibitory path to the inferior olive (IO). The inhibitory path contributes to the dentato-olivo-cerebellar loop (the short loop), while the excitatory path contributes to the cerebrocerebellar loop (the long loop). We propose a novel hypothesis: each loop contributes to physiologically distinct type of tremors or tremor-like movements. One type of irregular tremor-like movement is caused by a lesion in the cerebrocerebellar loop, which includes the primary path. A lesion in this loop affects the cerebellar forward model and deteriorates its accuracy of prediction and compensation of the feedback delay, resulting in irregular instability of voluntary motor control, i.e., cerebellar ataxia (CA). Therefore, this type of tremor, such as kinetic tremor, is usually associated with other symptoms of CA such as dysmetria. We call this type of tremor forward model-related tremor. The second type of regular tremor appears to be correlated with synchronized oscillation of IO neurons due, at least in animal models, to reduced degrees of freedom in IO activities. The regular burst activity of IO neurons is precisely transmitted along the cerebellocerebral path to the motor cortex before inducing rhythmical reciprocal activities of agonists and antagonists, i.e., tremor. We call this type of tremor IO-oscillation-related tremor. Although this type of regular tremor does not necessarily accompany ataxia, the aberrant IO activities (i.e., aberrant CS activities) may induce secondary maladaptation of cerebellar forward models through aberrant patterns of long-term depression (LTD) and/or long-term potentiation (LTP) of the cerebellar circuitry. Although our hypothesis does not cover all tremors or tremor-like movement disorders, our approach integrates the latest theories of cerebellar physiology and provides explanations how various lesions in or around the G-M triangle results in tremors or tremor-like movements. We propose that tremor results from errors in predictions carried out by the cerebellar circuitry.
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Affiliation(s)
- Shinji Kakei
- Department of Anatomy and Physiology, Jissen Women's University, Tokyo, Japan
| | - Mario Manto
- Service de Neurologie, Médiathèque Jean Jacquy, CHU-Charleroi, Charleroi, Belgium
- Service des Neurosciences, University of Mons, Mons, Belgium
| | - Hirokazu Tanaka
- Faculty of Information Technology, Tokyo City University, Tokyo, Japan
| | - Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University, Tokyo, Japan
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Miterko LN, Baker KB, Beckinghausen J, Bradnam LV, Cheng MY, Cooperrider J, DeLong MR, Gornati SV, Hallett M, Heck DH, Hoebeek FE, Kouzani AZ, Kuo SH, Louis ED, Machado A, Manto M, McCambridge AB, Nitsche MA, Taib NOB, Popa T, Tanaka M, Timmann D, Steinberg GK, Wang EH, Wichmann T, Xie T, Sillitoe RV. Consensus Paper: Experimental Neurostimulation of the Cerebellum. CEREBELLUM (LONDON, ENGLAND) 2019; 18:1064-1097. [PMID: 31165428 PMCID: PMC6867990 DOI: 10.1007/s12311-019-01041-5] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cerebellum is best known for its role in controlling motor behaviors. However, recent work supports the view that it also influences non-motor behaviors. The contribution of the cerebellum towards different brain functions is underscored by its involvement in a diverse and increasing number of neurological and neuropsychiatric conditions including ataxia, dystonia, essential tremor, Parkinson's disease (PD), epilepsy, stroke, multiple sclerosis, autism spectrum disorders, dyslexia, attention deficit hyperactivity disorder (ADHD), and schizophrenia. Although there are no cures for these conditions, cerebellar stimulation is quickly gaining attention for symptomatic alleviation, as cerebellar circuitry has arisen as a promising target for invasive and non-invasive neuromodulation. This consensus paper brings together experts from the fields of neurophysiology, neurology, and neurosurgery to discuss recent efforts in using the cerebellum as a therapeutic intervention. We report on the most advanced techniques for manipulating cerebellar circuits in humans and animal models and define key hurdles and questions for moving forward.
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Affiliation(s)
- Lauren N Miterko
- Department of Pathology and Immunology, Department of Neuroscience, Program in Developmental Biology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA
| | - Kenneth B Baker
- Neurological Institute, Department of Neurosurgery, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA
| | - Jaclyn Beckinghausen
- Department of Pathology and Immunology, Department of Neuroscience, Program in Developmental Biology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA
| | - Lynley V Bradnam
- Department of Exercise Science, Faculty of Science, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Michelle Y Cheng
- Department of Neurosurgery, Stanford University School of Medicine, 1201 Welch Road, MSLS P352, Stanford, CA, 94305-5487, USA
| | - Jessica Cooperrider
- Neurological Institute, Department of Neurosurgery, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA
| | - Mahlon R DeLong
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Simona V Gornati
- Department of Neuroscience, Erasmus Medical Center, 3015 AA, Rotterdam, Netherlands
| | - Mark Hallett
- Human Motor Control Section, NINDS, NIH, Building 10, Room 7D37, 10 Center Dr MSC 1428, Bethesda, MD, 20892-1428, USA
| | - Detlef H Heck
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, 855 Monroe Ave, Memphis, TN, 38163, USA
| | - Freek E Hoebeek
- Department of Neuroscience, Erasmus Medical Center, 3015 AA, Rotterdam, Netherlands
- NIDOD Department, Wilhelmina Children's Hospital, University Medical Center Utrecht Brain Center, Utrecht, Netherlands
| | - Abbas Z Kouzani
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - Sheng-Han Kuo
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | - Elan D Louis
- Department of Neurology, Yale School of Medicine, Department of Chronic Disease Epidemiology, Yale School of Public Health, Center for Neuroepidemiology and Clinical Research, Yale School of Medicine, Yale University, New Haven, CT, 06520, USA
| | - Andre Machado
- Neurological Institute, Department of Neurosurgery, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA
| | - Mario Manto
- Service de Neurologie, CHU-Charleroi, 6000, Charleroi, Belgium
- Service des Neurosciences, Université de Mons, 7000, Mons, Belgium
| | - Alana B McCambridge
- Graduate School of Health, Physiotherapy, University of Technology Sydney, PO Box 123, Broadway, Sydney, NSW, 2007, Australia
| | - Michael A Nitsche
- Department of Psychology and Neurosiences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany
- Department of Neurology, University Medical Hospital Bergmannsheil, Bochum, Germany
| | | | - Traian Popa
- Human Motor Control Section, NINDS, NIH, Building 10, Room 7D37, 10 Center Dr MSC 1428, Bethesda, MD, 20892-1428, USA
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Ecole Polytechnique Federale de Lausanne (EPFL), Sion, Switzerland
| | - Masaki Tanaka
- Department of Physiology, Hokkaido University School of Medicine, Sapporo, 060-8638, Japan
| | - Dagmar Timmann
- Department of Neurology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Gary K Steinberg
- Department of Neurosurgery, Stanford University School of Medicine, 1201 Welch Road, MSLS P352, Stanford, CA, 94305-5487, USA
- R281 Department of Neurosurgery, Stanfod University School of Medicine, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Eric H Wang
- Department of Neurosurgery, Stanford University School of Medicine, 1201 Welch Road, MSLS P352, Stanford, CA, 94305-5487, USA
| | - Thomas Wichmann
- Department of Neurology, Emory University, Atlanta, GA, 30322, USA
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, 30322, USA
| | - Tao Xie
- Department of Neurology, University of Chicago, 5841 S. Maryland Avenue, MC 2030, Chicago, IL, 60637-1470, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Department of Neuroscience, Program in Developmental Biology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA.
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Pan MK, Ni CL, Wu YC, Li YS, Kuo SH. Animal Models of Tremor: Relevance to Human Tremor Disorders. Tremor Other Hyperkinet Mov (N Y) 2018; 8:587. [PMID: 30402338 PMCID: PMC6214818 DOI: 10.7916/d89s37mv] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/10/2018] [Indexed: 12/17/2022] Open
Abstract
Background Tremor is the most common movement disorder; however, the pathophysiology of tremor remains elusive. While several neuropathological alterations in tremor disorders have been observed in post-mortem studies of human brains, a full understanding of the relationship between brain circuitry alterations and tremor requires testing in animal models. Additionally, tremor animal models are critical for our understanding of tremor pathophysiology, and/or to serve as a platform for therapy development. Methods A PubMed search was conducted in May 2018 to identify published papers for review. Results The methodology used in most studies on animal models of tremor lacks standardized measurement of tremor frequency and amplitude; instead, these studies are based on the visual inspection of phenotypes, which may fail to delineate tremor from other movement disorders such as ataxia. Of the animal models with extensive tremor characterization, harmaline-induced rodent tremor models provide an important framework showing that rhythmic and synchronous neuronal activities within the olivocerebellar circuit can drive action tremor. In addition, dopamine-depleted monkey and mouse models may develop rest tremor, highlighting the role of dopamine in rest tremor generation. Finally, other animal models of tremor have involvement of the cerebellar circuitry, leading to altered Purkinje cell physiology. Discussion Both the cerebellum and the basal ganglia are likely to play a role in tremor generation. While the cerebellar circuitry can generate rhythmic movements, the nigrostriatal system is likely to modulate the tremor circuit. Tremor disorders are heterogeneous in nature. Therefore, each animal model may represent a subset of tremor disorders, which collectively can advance our understanding of tremor.
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Affiliation(s)
- Ming-Kai Pan
- Department of Medical Research, National Taiwan University, Taipei, TW
| | - Chun-Lun Ni
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Yeuh-Chi Wu
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Yong-Shi Li
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Sheng-Han Kuo
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Gan SR, Wang J, Figueroa KP, Pulst SM, Tomishon D, Lee D, Perlman S, Wilmot G, Gomez CM, Schmahmann J, Paulson H, Shakkottai VG, Ying SH, Zesiewicz T, Bushara K, Geschwind MD, Xia G, Subramony SH, Ashizawa T, Kuo SH. Postural Tremor and Ataxia Progression in Spinocerebellar Ataxias. Tremor Other Hyperkinet Mov (N Y) 2017; 7:492. [PMID: 29057148 PMCID: PMC5647398 DOI: 10.7916/d8gm8krh] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 09/07/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Postural tremor can sometimes occur in spinocerebellar ataxias (SCAs). However, the prevalence and clinical characteristics of postural tremor in SCAs are poorly understood, and whether SCA patients with postural tremor have different ataxia progression is not known. METHODS We studied postural tremor in 315 patients with SCA1, 2, 3, and 6 recruited from the Clinical Research Consortium for Spinocerebellar Ataxias (CRC-SCA), which consists of 12 participating centers in the United States, and we evaluated ataxia progression in these patients from January 2010 to August 2012. RESULTS Among 315 SCA patients, postural tremor was most common in SCA2 patients (SCA1, 5.8%; SCA2, 27.5%; SCA3, 12.4%; SCA6, 16.9%; p = 0.007). SCA3 patients with postural tremor had longer CAG repeat expansions than SCA3 patients without postural tremor (73.67 ± 3.12 vs. 70.42 ± 3.96, p = 0.003). Interestingly, SCA1 and SCA6 patients with postural tremor had a slower rate of ataxia progression (SCA1, β = -0.91, p < 0.001; SCA6, β = -1.28, p = 0.025), while SCA2 patients with postural tremor had a faster rate of ataxia progression (β = 1.54, p = 0.034). We also found that the presence of postural tremor in SCA2 patients could be influenced by repeat expansions of ATXN1 (β = -1.53, p = 0.037) and ATXN3 (β = 0.57, p = 0.018), whereas postural tremor in SCA3 was associated with repeat lengths in TBP (β = 0.63, p = 0.041) and PPP2R2B (β = -0.40, p = 0.032). DISCUSSION Postural tremor could be a clinical feature of SCAs, and the presence of postural tremor could be associated with different rates of ataxia progression. Genetic interactions between ataxia genes might influence the brain circuitry and thus affect the clinical presentation of postural tremor.
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Affiliation(s)
- Shi-Rui Gan
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Jie Wang
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Basic and Community Nursing, School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Karla P. Figueroa
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Stefan M. Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Darya Tomishon
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Danielle Lee
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Susan Perlman
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - George Wilmot
- Department of Neurology, Emory University, Atlanta, GA, USA
| | | | - Jeremy Schmahmann
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Henry Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | | | - Sarah H. Ying
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
| | - Theresa Zesiewicz
- Department of Neurology, University of South Florida, Tampa, FL, USA
| | - Khalaf Bushara
- Department of Neurology, University of Minnesota, Minneapolis, MN, USA
| | | | - Guangbin Xia
- Department of Neurology, School of Medicine, University of New Mexico, Albuquerque, NM, USA
| | - S. H. Subramony
- Department of Neurology, School of Medicine, University of New Mexico, Albuquerque, NM, USA
| | | | - Sheng-Han Kuo
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Louis ED, Lenka A. The Olivary Hypothesis of Essential Tremor: Time to Lay this Model to Rest? Tremor Other Hyperkinet Mov (N Y) 2017; 7:473. [PMID: 28966877 PMCID: PMC5618117 DOI: 10.7916/d8ff40rx] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/09/2017] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Although essential tremor (ET) is the most common tremor disorder, its pathogenesis is not fully understood. The traditional model of ET, proposed in the early 1970s, posited that the inferior olivary nucleus (ION) was the prime generator of tremor in ET and that ET is a disorder of electrophysiological derangement, much like epilepsy. This article comprehensively reviews the origin and basis of this model, its merits and problems, and discusses whether it is time to lay this model to rest. METHODS A PubMed search was performed in March 2017 to identify articles for this review. RESULTS The olivary model gains support from the recognition of neurons with pacemaker property in the ION and the harmaline-induced tremor models (as the ION is the prime target of harmaline). However, the olivary model is problematic, as neurons with pacemaker property are not specific to the ION and the harmaline model does not completely represent the human disease ET. In addition, a large number of neuroimaging studies in ET have not detected structural or functional changes in the ION; rather, abnormalities have been reported in structures related to the cerebello-thalamo-cortical network. Moreover, a post-mortem study of microscopic changes in the ION did not detect any differences between ET cases and controls. DISCUSSION The olivary model largely remains a physiological construct. Numerous observations have cast considerable doubt as to the validity of this model in ET. Given the limitations of the model, we conclude that it is time now to lay this model to rest.
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Affiliation(s)
- Elan D. Louis
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
- Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA
- Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Abhishek Lenka
- Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences, Bangalore, India
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
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Kuo SH, Lin CY, Wang J, Sims PA, Pan MK, Liou JY, Lee D, Tate WJ, Kelly GC, Louis ED, Faust PL. Climbing fiber-Purkinje cell synaptic pathology in tremor and cerebellar degenerative diseases. Acta Neuropathol 2017; 133:121-138. [PMID: 27704282 DOI: 10.1007/s00401-016-1626-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 09/26/2016] [Accepted: 09/28/2016] [Indexed: 12/19/2022]
Abstract
Changes in climbing fiber-Purkinje cell (CF-PC) synaptic connections have been found in the essential tremor (ET) cerebellum, and these changes are correlated with tremor severity. Whether these postmortem changes are specific to ET remains to be investigated. We assessed CF-PC synaptic pathology in the postmortem cerebellum across a range of degenerative movement disorders [10 Parkinson's disease (PD) cases, 10 multiple system atrophy (MSA) cases, 10 spinocerebellar ataxia type 1 (SCA1) cases, and 20 ET cases] and 25 controls. We observed differences in terms of CF pathological features across these disorders. Specifically, PD cases and ET cases both had more CFs extending into the parallel fiber (PF) territory, but ET cases had more complex branching and increased length of CFs in the PF territory along with decreased CF synaptic density compared to PD cases. MSA cases and SCA1 cases had the most severely reduced CF synaptic density and a marked paucity of CFs extending into the PF territory. Furthermore, CFs in a subset of MSA cases formed collateral branches parallel to the PC layer, a feature not seen in other diagnostic groups. Using unsupervised cluster analysis, the cases and controls could all be categorized into four clusters based on the CF pathology and features of PC pathology, including counts of PCs and their axonal torpedoes. ET cases and PD cases co-segregated into two clusters, whereas SCA1 cases and MSA cases formed another cluster, separate from the control cluster. Interestingly, the presence of resting tremor seemed to be the clinical feature that separated the cases into the two ET-PD clusters. In conclusion, our study demonstrates that these degenerative movement disorders seem to differ with respect to the pattern of CF synaptic pathology they exhibit. It remains to be determined how these differences contribute to the clinical presentations of these diseases.
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Wang J, Kelly GC, Tate WJ, Li YS, Lee M, Gutierrez J, Louis ED, Faust PL, Kuo SH. Excitatory Amino acid transporter expression in the essential tremor dentate nucleus and cerebellar cortex: A postmortem study. Parkinsonism Relat Disord 2016; 32:87-93. [PMID: 27624392 PMCID: PMC5501729 DOI: 10.1016/j.parkreldis.2016.09.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/25/2016] [Accepted: 09/05/2016] [Indexed: 12/17/2022]
Abstract
BACKGROUND Genome-wide association studies have revealed a link between essential tremor (ET) and the gene SLC1A2, which encodes excitatory amino acid transporter type 2 (EAAT2). We explored EAAT biology in ET by quantifying EAAT2 and EAAT1 levels in the cerebellar dentate nucleus, and expanded our prior analysis of EAAT2 levels in the cerebellar cortex. OBJECTIVE To quantify EAAT2 and EAAT1 levels in the cerebellar dentate nucleus and cerebellar cortex of ET cases vs. CONTROLS METHODS We used immunohistochemistry to quantify EAAT2 and EAAT1 levels in the dentate nucleus of a discovery cohort of 16 ET cases and 16 controls. Furthermore, we quantified EAAT2 levels in the dentate nucleus in a replicate cohort (61 ET cases, 25 controls). Cortical EAAT2 levels in all 77 ET cases and 41 controls were quantified. RESULTS In the discovery cohort, dentate EAAT2 levels were 1.5-fold higher in 16 ET cases vs. 16 controls (p = 0.007), but EAAT1 levels did not differ significantly (p = 0.279). Dentate EAAT2 levels were 1.3-fold higher in 61 ET cases vs. 25 controls in the replicate cohort (p = 0.022). Cerebellar cortical EAAT2 levels were 20% and 40% lower in ET cases vs. controls in the discovery and the replicate cohorts (respective p values = 0.045 and < 0.001). CONCLUSION EAAT2 expression is enhanced in the ET dentate nucleus, in contrast to differentially reduced EAAT2 levels in the ET cerebellar cortex, which might reflect a compensatory mechanism to maintain excitation-inhibition balance in cerebellar nuclei.
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Affiliation(s)
- Jie Wang
- Department of Basic and Community Nursing, School of Nursing, Nanjing Medical University, Nanjing, Jiangsu Province, China; Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Geoffrey C Kelly
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - William J Tate
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Yong-Shi Li
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Michelle Lee
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Jesus Gutierrez
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA; Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA; Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Sheng-Han Kuo
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
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Lee M, Cheng MM, Lin CY, Louis ED, Faust PL, Kuo SH. Decreased EAAT2 protein expression in the essential tremor cerebellar cortex. Acta Neuropathol Commun 2014; 2:157. [PMID: 25391854 PMCID: PMC4239402 DOI: 10.1186/s40478-014-0157-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 10/21/2014] [Indexed: 11/10/2022] Open
Abstract
Genetic polymorphisms in Solute carrier family 1 (glial high affinity glutamate transporter), member 2 (SLC1A2) have been linked with essential tremor. SLC1A2 encodes excitatory amino acid transporter type 2 (EAAT2), which clears glutamate from the synaptic cleft. One postulated mechanism for essential tremor is the over-excitation of glutamatergic olivo-cerebellar climbing fibers, leading to excitotoxic death of Purkinje cells. Other glutamatergic excitatory signals are transmitted to Purkinje cells via parallel fibers of cerebellar granule neurons. Therefore, the expression level of glutamate transporters could be important in essential tremor pathogenesis. Using Western blotting, we compared the expression levels of the two main glutamate transporters in the cerebellar cortex, EAAT1 and EAAT2, in postmortem tissue from 16 essential tremor cases and 13 age-matched controls. We also studied the localization of EAAT1 and EAAT2 using immunohistochemistry in 10 essential tremor cases and 12 controls. EAAT1 protein levels were similar in cases and controls (1.12 ± 0.83 vs. 1.01 ± 0.69, p =0.71) whereas EAAT2 protein levels in essential tremor cases were only 1/3 of that in controls (0.35 ± 0.23 vs. 1.00 ± 0.62, p < 0.01). Interestingly, EAAT2, but not EAAT1, was expressed in astrocytic processes surrounding the Purkinje cell axon initial segment, a region of previously observed pathological changes in essential tremor. Our main finding, a significant reduction in cerebellar cortical EAAT2 protein levels in essential tremor, suggests that Purkinje cells in essential tremor might be more vulnerable to excitotoxic damage than those of controls.
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Lin CY, Louis ED, Faust PL, Koeppen AH, Vonsattel JPG, Kuo SH. Abnormal climbing fibre-Purkinje cell synaptic connections in the essential tremor cerebellum. ACTA ACUST UNITED AC 2014; 137:3149-59. [PMID: 25273997 DOI: 10.1093/brain/awu281] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Structural changes in Purkinje cells have been identified in the essential tremor cerebellum, although the mechanisms that underlie these changes remain poorly understood. Climbing fibres provide one of the major excitatory inputs to Purkinje cells, and climbing fibre-Purkinje cell connections are essential for normal cerebellar-mediated motor control. The distribution of climbing fibre-Purkinje cell synapses on Purkinje cell dendrites is dynamically regulated and may be altered in disease states. The aim of the present study was to examine the density and distribution of climbing fibre-Purkinje cell synapses using post-mortem cerebellar tissue of essential tremor cases and controls. Using vesicular glutamate transporter type 2 immunohistochemistry, we labelled climbing fibre-Purkinje cell synapses of 12 essential tremor cases and 13 age-matched controls from the New York Brain Bank. Normally, climbing fibres form synapses mainly on the thick, proximal Purkinje cell dendrites in the inner portion of the molecular layer, whereas parallel fibres form synapses on the thin, distal Purkinje cell spiny branchlets. We observed that, compared with controls, essential tremor cases had decreased climbing fibre-Purkinje cell synaptic density, more climbing fibres extending to the outer portion of the molecular layer, and more climbing fibre-Purkinje cell synapses on the thin Purkinje cell spiny branchlets. Interestingly, in essential tremor, the increased distribution of climbing fibre-Purkinje cell synapses on the thin Purkinje cell branchlets was inversely associated with clinical tremor severity, indicating a close relationship between the altered distribution of climbing fibre-Purkinje cell connections and tremor. These findings suggest that abnormal climbing fibre-Purkinje cell connections could be of importance in the pathogenesis of essential tremor.
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Affiliation(s)
- Chi-Ying Lin
- 1 Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Elan D Louis
- 1 Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA 2 GH Sergievsky Centre, Columbia University, New York, NY, USA 3 Taub Institute for Research of Alzheimer's disease and the Aging Brain, Columbia University, New York, NY, USA 4 Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Phyllis L Faust
- 5 Department of Pathology and Cell Biology, Columbia University Medical Centre and the New York Presbyterian Hospital, New York, NY, USA
| | - Arnulf H Koeppen
- 6 Neurology and Research Services, Veterans Affairs Medical Centre, Albany, NY, USA 7 Departments of Neurology and Pathology, Albany Medical College, Albany, NY, USA
| | - Jean-Paul G Vonsattel
- 3 Taub Institute for Research of Alzheimer's disease and the Aging Brain, Columbia University, New York, NY, USA 5 Department of Pathology and Cell Biology, Columbia University Medical Centre and the New York Presbyterian Hospital, New York, NY, USA
| | - Sheng-Han Kuo
- 1 Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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