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Rios-Zermeno J, Ballesteros-Herrera D, Dominguez-Vizcayno P, Carrillo-Ruiz JD, Moreno-Jimenez S. Dentate nucleus: a review and implications for dentatotomy. Acta Neurochir (Wien) 2024; 166:219. [PMID: 38758379 DOI: 10.1007/s00701-024-06104-z] [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: 02/27/2024] [Accepted: 04/27/2024] [Indexed: 05/18/2024]
Abstract
PURPOSE The dentate nucleus (DN) is the largest, most lateral, and phylogenetically most recent of the deep cerebellar nuclei. Its pivotal role encompasses the planning, initiation, and modification of voluntary movement but also spans non-motor functions like executive functioning, visuospatial processing, and linguistic abilities. This review aims to offer a comprehensive description of the DN, detailing its embryology, anatomy, physiology, and clinical relevance, alongside an analysis of dentatotomy. METHODS AND RESULTS We delve into the history, embryology, anatomy, vascular supply, imaging characteristics, and clinical significance of the DN. Furthermore, we thoroughly review the dentatotomy, emphasizing its role in treating spasticity. CONCLUSIONS Understanding the intricacies of the anatomy, physiology, vasculature, and projections of the DN has taken on increased importance in current neurosurgical practice. Advances in technology have unveiled previously unknown functions of the deep cerebellar nuclei, predominantly related to non-motor domains. Such discoveries are revitalizing older techniques, like dentatotomy, and applying them to newer, more localized targets.
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Affiliation(s)
- Jorge Rios-Zermeno
- Department of Neurosurgery, Instituto Nacional de Neurologia y Neurocirugia, Av Insurgentes Sur 3877, Tlalpan, Mexico City, Mexico
| | - Daniel Ballesteros-Herrera
- Department of Neurosurgery, Instituto Nacional de Neurologia y Neurocirugia, Av Insurgentes Sur 3877, Tlalpan, Mexico City, Mexico
| | - Pamela Dominguez-Vizcayno
- Department of Radioneurosurgery, Instituto Nacional de Neurologia y Neurocirugia, Mexico City, Mexico
| | - José Damián Carrillo-Ruiz
- Research Direction & Stereotactic and Functional Neurosurgery, Mexico General Hospital, Mexico City, Mexico
- Neuroscience CoordinationPschycology Faculty, Mexico Anahuac University, Mexico City, Mexico
| | - Sergio Moreno-Jimenez
- Department of Neurosurgery, Instituto Nacional de Neurologia y Neurocirugia, Av Insurgentes Sur 3877, Tlalpan, Mexico City, Mexico.
- Neurological Center, American British Cowdray Medical Center, Mexico City, Mexico.
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Buijink AWG, Prent N, Puts NA, Schrantee A, Potters WV, van Rootselaar AF. GABA, Glutamate, and NAA Levels in the Deep Cerebellar Nuclei of Essential Tremor Patients. Front Neurol 2021; 12:664735. [PMID: 34025569 PMCID: PMC8136412 DOI: 10.3389/fneur.2021.664735] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/12/2021] [Indexed: 01/10/2023] Open
Abstract
Background: Essential tremor is among the commonly observed movement disorders in clinical practice, however the exact pathophysiological mechanisms underlying tremor are unknown. It has been suggested that Purkinje cell alterations play a causal factor in tremorgenesis. Altered levels of inhibitory (GABA) and excitatory (glutamate+glutamine, Glx) neurotransmitters could be markers for Purkinje cell alterations. We hypothesize that GABA and Glx levels in the dentate nuclei could be differentially altered in patients responsive to either anticonvulsants or β-adrenergic blockers. Methods: In this explorative study in patients with essential tremor, we measured gamma-aminobutyric acid (GABA) and glutamate+glutamine (Glx) levels in the dentate nucleus region using 1H-magnetic resonance spectroscopy (MRS) in seven patients using propranolol, five patients using anticonvulsants, and eight healthy controls. Results: There were no group differences with respect to GABA+/Cr, Glx/Cr, NAA/Cr, and GABA+/Glx ratios. There was no correlation with tremor severity. Discussion: Our results are in line with previously published studies; however, additional studies on a larger number of patients are warranted to confirm these findings. Furthermore medication-subgroups did not exhibit differences with respect to GABA+/Cr, Glx/Cr, NAA/Cr, and GABA+/Glx ratios. A recent study, of similar size, found an inverse association between tremor severity and the GABA+/Glx ratio in the cerebellum of essential tremor patients. We were unable to replicate these findings. The field of tremor research is plagued by heterogeneous results, and we would caution against drawing firm conclusions based on pilot studies.
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Affiliation(s)
- Arthur W. G. Buijink
- Department of Neurology and Clinical Neurophysiology, Amsterdam University Medical Centers, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Naomi Prent
- Department of Neurology and Clinical Neurophysiology, Amsterdam University Medical Centers, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Nicolaas A. Puts
- Department of Forensic and Neurodevelopmental Sciences, Sackler Institute for Translational Neurodevelopment, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, United Kingdom
| | - Anouk Schrantee
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Wouter V. Potters
- Department of Neurology and Clinical Neurophysiology, Amsterdam University Medical Centers, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Anne-Fleur van Rootselaar
- Department of Neurology and Clinical Neurophysiology, Amsterdam University Medical Centers, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
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Alonso-Navarro H, García-Martín E, Agúndez JA, Jiménez-Jiménez FJ. Current and Future Neuropharmacological Options for the Treatment of Essential Tremor. Curr Neuropharmacol 2020; 18:518-537. [PMID: 31976837 PMCID: PMC7457404 DOI: 10.2174/1570159x18666200124145743] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/31/2019] [Accepted: 01/23/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Essential Tremor (ET) is likely the most frequent movement disorder. In this review, we have summarized the current pharmacological options for the treatment of this disorder and discussed several future options derived from drugs tested in experimental models of ET or from neuropathological data. METHODS A literature search was performed on the pharmacology of essential tremors using PubMed Database from 1966 to July 31, 2019. RESULTS To date, the beta-blocker propranolol and the antiepileptic drug primidone are the drugs that have shown higher efficacy in the treatment of ET. Other drugs tested in ET patients have shown different degrees of efficacy or have not been useful. CONCLUSION Injections of botulinum toxin A could be useful in the treatment of some patients with ET refractory to pharmacotherapy. According to recent neurochemical data, drugs acting on the extrasynaptic GABAA receptors, the glutamatergic system or LINGO-1 could be interesting therapeutic options in the future.
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Affiliation(s)
| | | | | | - Félix J. Jiménez-Jiménez
- Address correspondence to this author at the Section of Neurology, Hospital Universitario del Sureste, Arganda del Rey, Madrid, Spain; Tel: +34636968395; Fax: +34913280704; E-mails: ;
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Louis ED, Hernandez N, Dyke JP, Ma RE, Dydak U. In Vivo Dentate Nucleus Gamma-aminobutyric Acid Concentration in Essential Tremor vs. Controls. THE CEREBELLUM 2019; 17:165-172. [PMID: 29039117 DOI: 10.1007/s12311-017-0891-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Despite its high prevalence, essential tremor (ET) is among the most poorly understood neurological diseases. The presence and extent of Purkinje cell (PC) loss in ET is the subject of controversy. PCs are a major storehouse of central nervous system gamma-aminobutyric acid (GABA), releasing GABA at the level of the dentate nucleus. It is therefore conceivable that cerebellar dentate nucleus GABA concentration could be an in vivo marker of PC number. We used in vivo 1H magnetic resonance spectroscopy (MRS) to quantify GABA concentrations in two cerebellar volumes of interest, left and right, which included the dentate nucleus, comparing 45 ET cases to 35 age-matched controls. 1H MRS was performed using a 3.0-T Siemens Tim Trio scanner. The MEGA-PRESS J-editing sequence was used for GABA detection in two cerebellar volumes of interest (left and right) that included the dentate nucleus. The two groups did not differ with respect to our primary outcome of GABA concentration (given in institutional units). For the right dentate nucleus, [GABA] in ET cases = 2.01 ± 0.45 and [GABA] in controls = 1.86 ± 0.53, p = 0.17. For the left dentate nucleus, [GABA] in ET cases = 1.68 ± 0.49 and [GABA] controls = 1.80 ± 0.53, p = 0.33. The controls had similar dentate nucleus [GABA] in the right vs. left dentate nucleus (p = 0.52); however, in ET cases, the value on the right was considerably higher than that on the left (p = 0.001). We did not detect a reduction in dentate nucleus GABA concentration in ET cases vs. CONTROLS One interpretation of the finding is that it does not support the existence of PC loss in ET; however, an alternative interpretation is the observed pattern could be due to the effects of terminal sprouting in ET (i.e., collateral sprouting from surviving PCs making up for the loss of GABA-ergic terminals from PC degeneration). Further research is needed.
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Affiliation(s)
- Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, LCI 710, 15 York Street, PO Box 208018, New Haven, CT, 06520-8018, 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.
| | - Nora Hernandez
- Department of Neurology, Yale School of Medicine, Yale University, LCI 710, 15 York Street, PO Box 208018, New Haven, CT, 06520-8018, USA
| | - Jonathan P Dyke
- Department of Radiology, Weill Cornell Medical College, New York, NY, USA
| | - Ruoyun E Ma
- School of Health Sciences, Purdue University, West Lafayette, IN, USA.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ulrike Dydak
- School of Health Sciences, Purdue University, West Lafayette, IN, USA.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
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Schaefer SM, Vives Rodriguez A, Louis ED. Brain circuits and neurochemical systems in essential tremor: insights into current and future pharmacotherapeutic approaches. Expert Rev Neurother 2017; 18:101-110. [PMID: 29206482 DOI: 10.1080/14737175.2018.1413353] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION There are few medications that are available for the treatment of essential tremor (ET) and they are only moderately effective. Areas covered: Data were obtained from a PubMed search. Original articles, review articles, and clinical guidelines were included. Two disease models for ET have been proposed: 1) the olivary model, which attributes ET to a pathological pacemaker in the inferior olivary nucleus, and 2) the cerebellar degeneration model, which postulates that ET originates in the cerebellum and could be related to deficient or abnormal Purkinje cell (PC) output. Underlying biochemical dysfunction in T-type calcium channels (T-tCaC) may loosely be linked to the first model and deficiency/abnormality in γ-aminobutyric acid (GABA) neurotransmission, to the second. Expert commentary: Human data points robustly to the role of GABA in ET. Numerous medications that target the GABA system have been tried, with variable success. Given the many different types of GABA-ergic neurons, and the multitude of GABAA receptor subtypes, a given medication could have competing/cancelling effects. It would seem that influencing GABA receptors broadly is not as effective as targeting certain GABAA receptor subtypes. Future research should seek to identify molecular candidates that have a more targeted effect within the GABA system.
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Affiliation(s)
- Sara M Schaefer
- a Department of Neurology , Yale School of Medicine, Yale University , New Haven , CT , USA
| | - Ana Vives Rodriguez
- a Department of Neurology , Yale School of Medicine, Yale University , New Haven , CT , USA
| | - Elan D Louis
- a Department of Neurology , Yale School of Medicine, Yale University , New Haven , CT , USA.,b Department of Chronic Disease Epidemiology , Yale School of Public Health, Yale University , New Haven , CT , USA.,c Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine , Yale University , New Haven , CT , USA
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Dyke JP, Cameron E, Hernandez N, Dydak U, Louis ED. Gray matter density loss in essential tremor: a lobule by lobule analysis of the cerebellum. CEREBELLUM & ATAXIAS 2017; 4:10. [PMID: 28680651 PMCID: PMC5494891 DOI: 10.1186/s40673-017-0069-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 06/29/2017] [Indexed: 11/23/2022]
Abstract
Background The pathophysiological basis for essential tremor (ET) remains unclear, although evidence increasingly links it to a disordered and perhaps degenerative cerebellum. Prior imaging studies have treated the cerebellum en bloc. Our hypothesis was that regional differences in cerebellar gray matter (GM) density may better distinguish ET cases from controls. Forty-seven ET cases and 36 control subjects were imaged using magnetic resonance imaging (MRI). The cerebellum was segmented into 34 lobes using a Spatially Unbiased Infra-Tentorial Template (SUIT) atlas within the Statistical Parametric Mapping (SPM) analysis package. Age, gender and Montreal Cognitive Assessment (MoCA) scores were regressed out from the statistical models to isolate group effects. ET cases were further stratified into phenotypically-defined subgroups. The Benjamini-Hochberg False Discovery Rate procedure (BH FDR) (α = 0.1) was used to correct for multiple comparisons. Results When all ET cases and controls were compared, none of the regions met the BH FDR criteria for significance. When compared with controls, ET cases with head or jaw tremor (n = 27) had significant changes in GM density in nine cerebellar lobules, with a majority in the left cerebellar region, and each meeting the BH FDR criteria. Likewise, ET cases with voice tremor (n = 22) exhibited significant changes in 11 lobules in both left and right regions and the vermis. These analyses, in sum, indicated decreases in GM density in lobules I-IV, V, VI, VII and VIII as well as the vermis. ET cases with severe tremor (n = 20) did not show regions of change that survived the BH FDR procedure when compared to controls. Conclusions We showed that ET cases with various forms of cranial tremor differed from controls with respect to cerebellar GM density, with evidence of GM reduction across multiple cerebellar regions. Additional work, using a lobule-by-lobule approach, is needed to confirm these results and precisely map the regional differences in ET cases, subgroups of ET cases, and controls.
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Affiliation(s)
- Jonathan P Dyke
- Department of Radiology, Citigroup Biomedical Imaging Center, Weill Cornell Medicine, New York, NY USA
| | - Eric Cameron
- School of Health Sciences, Purdue University, West Lafayette, IN USA.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN USA
| | - Nora Hernandez
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT USA
| | - Ulrike Dydak
- School of Health Sciences, Purdue University, West Lafayette, IN USA.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN 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.,Departments of Neurology and Chronic Disease Epidemiology Yale School of Medicine, Yale School of Public Health Yale University, New Haven, CT USA
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