1
|
Chalif JI, Mentis GZ. Normal Development and Pathology of Motoneurons: Anatomy, Electrophysiological Properties, Firing Patterns and Circuit Connectivity. ADVANCES IN NEUROBIOLOGY 2022; 28:63-85. [PMID: 36066821 DOI: 10.1007/978-3-031-07167-6_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This chapter will provide an introduction into motoneuron anatomy, electrophysiological properties, firing patterns focusing on development and also describing several pathological conditions that affect mononeurons. It starts with a historical retrospective describing the early landmark work into motoneurons. The next section lays out the various types of motoneurons (alpha, beta, and gamma) and their subclasses (fast-twitch fatigable, fast-twitch fatigue-resistant, and slow-twitch fatigue resistant), highlighting the functional relevance of this classification scheme. The third section describes the development of motoneurons' passive and active electrophysiological properties. This section also defines the major terms one uses in describing how a neuron functions electrophysiologically. The electrophysiological aspects of a neuron is critical to understanding how it behaves within a circuit and contributes to behavior since the firing of an action potential is how neurons communicate with each other and with muscles. The electrophysiological changes of motoneurons over development underlies how their function changes over the lifetime of an organism. After describing the properties of individual motoneurons, the chapter then turns to revealing how motoneurons interact within complex neural circuits, with other motoneurons as well as sensory neurons, and how these circuits change over development. Finally, this chapter ends with highlighting some recent advances made in motoneuron pathology, focusing on spinal muscular atrophy, amyotrophic lateral sclerosis, and axotomy.
Collapse
Affiliation(s)
- Joshua I Chalif
- Departments of Neurology and Pathology & Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard University, Boston, MA, USA
| | - George Z Mentis
- Departments of Neurology and Pathology & Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA.
| |
Collapse
|
2
|
Lee H, Lee JJ, Park NY, Dubey SK, Kim T, Ruan K, Lim SB, Park SH, Ha S, Kovlyagina I, Kim KT, Kim S, Oh Y, Kim H, Kang SU, Song MR, Lloyd TE, Maragakis NJ, Hong YB, Eoh H, Lee G. Multi-omic analysis of selectively vulnerable motor neuron subtypes implicates altered lipid metabolism in ALS. Nat Neurosci 2021; 24:1673-1685. [PMID: 34782793 PMCID: PMC8639773 DOI: 10.1038/s41593-021-00944-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 09/16/2021] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating disorder in which motor neurons degenerate, the causes of which remain unclear. In particular, the basis for selective vulnerability of spinal motor neurons (sMNs) and resistance of ocular motor neurons to degeneration in ALS has yet to be elucidated. Here, we applied comparative multi-omics analysis of human induced pluripotent stem cell-derived sMNs and ocular motor neurons to identify shared metabolic perturbations in inherited and sporadic ALS sMNs, revealing dysregulation in lipid metabolism and its related genes. Targeted metabolomics studies confirmed such findings in sMNs of 17 ALS (SOD1, C9ORF72, TDP43 (TARDBP) and sporadic) human induced pluripotent stem cell lines, identifying elevated levels of arachidonic acid. Pharmacological reduction of arachidonic acid levels was sufficient to reverse ALS-related phenotypes in both human sMNs and in vivo in Drosophila and SOD1G93A mouse models. Collectively, these findings pinpoint a catalytic step of lipid metabolism as a potential therapeutic target for ALS.
Collapse
Affiliation(s)
- Hojae Lee
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The Robert Packard Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jae Jin Lee
- Department of Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA, USA
| | - Na Young Park
- Department of Biochemistry, College of Medicine, Dong-A University, Busan, Korea
- Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan, Korea
| | - Sandeep Kumar Dubey
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Taeyong Kim
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Kai Ruan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Su Bin Lim
- Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon, Korea
| | - Seong-Hyun Park
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shinwon Ha
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Irina Kovlyagina
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Kyung-Tai Kim
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
- Jeonbuk Branch Institute, Korea Institute of Toxicology, Jeongeup, Republic of Korea
| | - Seongjun Kim
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yohan Oh
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Science, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea
| | - Hyesoo Kim
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sung-Ung Kang
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mi-Ryoung Song
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Thomas E Lloyd
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular and Molecular Medicine Program, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Nicholas J Maragakis
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Young Bin Hong
- Department of Biochemistry, College of Medicine, Dong-A University, Busan, Korea.
- Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan, Korea.
| | - Hyungjin Eoh
- Department of Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA, USA.
| | - Gabsang Lee
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- The Robert Packard Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
3
|
When assistive eye tracking fails: Communicating with a brainstem-stroke patient through the pupillary accommodative response – A case study. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
4
|
Hoh JFY. Myosin heavy chains in extraocular muscle fibres: Distribution, regulation and function. Acta Physiol (Oxf) 2021; 231:e13535. [PMID: 32640094 DOI: 10.1111/apha.13535] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 07/02/2020] [Indexed: 12/13/2022]
Abstract
This review examines kinetic properties and distribution of the 11 isoforms of myosin heavy chain (MyHC) expressed in extraocular muscle (EOM) fibre types and the regulation and function of these MyHCs. Although recruitment and discharge characteristics of ocular motoneurons during fixation and eye movements are well documented, work directly linking these properties with motor unit contractile speed and MyHC composition is lacking. Recruitment of motor units according to Henneman's size principle has some support in EOMs but needs consolidation. Both neurogenic and myogenic mechanisms regulate MyHC expression as in other muscle allotypes. Developmentally, multiply-innervated (MIFs) and singly-innervated fibres (SIFs) are derived presumably from distinct myoblast lineages, ending up expressing MyHCs in the slow and fast ends of the kinetic spectrum respectively. They modulate the synaptic inputs of their motoneurons through different retrogradely transported neurotrophins, thereby specifying their tonic and phasic impulse patterns. Immunohistochemical analyses of EOMs regenerating in situ and in limb muscle beds suggest that the very impulse patterns driving various ocular movements equip effectors with appropriate MyHC compositions and speeds to accomplish their tasks. These experiments also suggest that satellite cells of SIFs and MIFs are distinct lineages expressing different MyHCs during regeneration. MyHC compositions and functional characteristics of orbital fibres show longitudinal variations that facilitate linear ocular rotation during saccades. Palisade endings on global MIFs are postulated to respond to active and passive tensions by triggering axon reflexes that play important roles during fixation, saccades and vergence. How EOMs implement Listings law during ocular rotation is discussed.
Collapse
Affiliation(s)
- Joseph F. Y. Hoh
- Discipline of Physiology and the Bosch Institute School of Medical Sciences Faculty of Medicine and Health The University of Sydney Sydney NSW Australia
| |
Collapse
|
5
|
Protocadherin-Mediated Cell Repulsion Controls the Central Topography and Efferent Projections of the Abducens Nucleus. Cell Rep 2020; 24:1562-1572. [PMID: 30089266 DOI: 10.1016/j.celrep.2018.07.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/31/2018] [Accepted: 07/06/2018] [Indexed: 11/21/2022] Open
Abstract
Cranial motor nuclei in the brainstem innervate diverse types of head and neck muscles. Failure in establishing these neuromuscular connections causes congenital cranial dysinnervation disorders (CCDDs) characterized by abnormal craniofacial movements. However, mechanisms that link cranial motor nuclei to target muscles are poorly understood at the molecular level. Here, we report that protocadherin-mediated repulsion mediates neuromuscular connection in the ocular motor system in zebrafish. We identify pools of abducens motor neurons that are topographically arranged according to soma size and convergently innervate a single muscle. Disruptions of Duane retraction syndrome-associated transcription factors reveal that these neurons require Mafba/MAFB, but not Sall4/SALL4, for differentiation. Furthermore, genetic perturbations of Pcdh17/protocadherin-17 result in defective axon growth and soma clumping, thereby abolishing neuromuscular connectivity. Our results suggest that protocadherin-mediated repulsion forms the central topography and efferent projection pattern of the abducens nucleus following Mafba-dependent specification and imply potential involvement of protocadherins in CCDD etiology.
Collapse
|
6
|
Noronha B, Dziemian S, Zito GA, Konnaris C, Faisal AA. "Wink to grasp" - comparing eye, voice & EMG gesture control of grasp with soft-robotic gloves. IEEE Int Conf Rehabil Robot 2018; 2017:1043-1048. [PMID: 28813959 DOI: 10.1109/icorr.2017.8009387] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ability of robotic rehabilitation devices to support paralysed end-users is ultimately limited by the degree to which human-machine-interaction is designed to be effective and efficient in translating user intention into robotic action. Specifically, we evaluate the novel possibility of binocular eye-tracking technology to detect voluntary winks from involuntary blink commands, to establish winks as a novel low-latency control signal to trigger robotic action. By wearing binocular eye-tracking glasses we enable users to directly observe their environment or the actuator and trigger movement actions, without having to interact with a visual display unit or user interface. We compare our novel approach to two conventional approaches for controlling robotic devices based on electromyo-graphy (EMG) and speech-based human-computer interaction technology. We present an integrated software framework based on ROS that allows transparent integration of these multiple modalities with a robotic system. We use a soft-robotic SEM glove (Bioservo Technologies AB, Sweden) to evaluate how the 3 modalities support the performance and subjective experience of the end-user when movement assisted. All 3 modalities are evaluated in streaming, closed-loop control operation for grasping physical objects. We find that wink control shows the lowest error rate mean with lowest standard deviation of (0.23 ± 0.07, mean ± SEM) followed by speech control (0.35 ± 0. 13) and EMG gesture control (using the Myo armband by Thalamic Labs), with the highest mean and standard deviation (0.46 ± 0.16). We conclude that with our novel own developed eye-tracking based approach to control assistive technologies is a well suited alternative to conventional approaches, especially when combined with 3D eye-tracking based robotic end-point control.
Collapse
|
7
|
Maimon-Dror RO, Fernandez-Quesada J, Zito GA, Konnaris C, Dziemian S, Faisal AA. Towards free 3D end-point control for robotic-assisted human reaching using binocular eye tracking. IEEE Int Conf Rehabil Robot 2018; 2017:1049-1054. [PMID: 28813960 DOI: 10.1109/icorr.2017.8009388] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Eye-movements are the only directly observable behavioural signals that are highly correlated with actions at the task level, and proactive of body movements and thus reflect action intentions. Moreover, eye movements are preserved in many movement disorders leading to paralysis (or amputees) from stroke, spinal cord injury, Parkinson's disease, multiple sclerosis, and muscular dystrophy among others. Despite this benefit, eye tracking is not widely used as control interface for robotic interfaces in movement impaired patients due to poor human-robot interfaces. We demonstrate here how combining 3D gaze tracking using our GT3D binocular eye tracker with custom designed 3D head tracking system and calibration method enables continuous 3D end-point control of a robotic arm support system. The users can move their own hand to any location of the workspace by simple looking at the target and winking once. This purely eye tracking based system enables the end-user to retain free head movement and yet achieves high spatial end point accuracy in the order of 6 cm RMSE error in each dimension and standard deviation of 4 cm. 3D calibration is achieved by moving the robot along a 3 dimensional space filling Peano curve while the user is tracking it with their eyes. This results in a fully automated calibration procedure that yields several thousand calibration points versus standard approaches using a dozen points, resulting in beyond state-of-the-art 3D accuracy and precision.
Collapse
|
8
|
Kim HJ, Oh JH, Kang SY. Bilateral Adduction Palsy in a Patient with Myotonic Dystrophy Type 1. Exp Neurobiol 2016; 25:143-5. [PMID: 27358583 PMCID: PMC4923359 DOI: 10.5607/en.2016.25.3.143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/13/2016] [Accepted: 05/15/2016] [Indexed: 11/29/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is caused by CTG repeat expansion in the DMPK gene in chromosome 19q13.3. External ophthalmoplegia is a rare manifestation in DM1. We report a DM1 patient confirmed by the presence of 650 CTG triplet expansions in the DMPK gene and had limitation of adduction gaze bilaterally. Brain MRI showed bilateral medial rectus muscles atrophy. Our patient provides additional evidence of ocular motor muscle involvement in DM1.
Collapse
Affiliation(s)
- Hong-Jeon Kim
- Department of Neurology, Jeju National University School of Medicine, Jeju 63241, Korea
| | - Jung-Hwan Oh
- Department of Neurology, Jeju National University School of Medicine, Jeju 63241, Korea
| | - Sa-Yoon Kang
- Department of Neurology, Jeju National University School of Medicine, Jeju 63241, Korea
| |
Collapse
|
9
|
Isolation of Mouse Periocular Tissue for Histological and Immunostaining Analyses of the Extraocular Muscles and Their Satellite Cells. Methods Mol Biol 2016; 1460:101-27. [PMID: 27492169 DOI: 10.1007/978-1-4939-3810-0_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The extraocular muscles (EOMs) comprise a group of highly specialized skeletal muscles controlling eye movements. Although a number of unique features of EOMs including their sparing in Duchenne muscular dystrophy have drawn a continuous interest, knowledge about these hard to reach muscles is still limited. The goal of this chapter is to provide detailed methods for the isolation and histological analysis of mouse EOMs. We first introduce in brief the basic anatomy and established nomenclature of the extraocular primary and accessory muscles. We then provide a detailed description with step-by-step images of our procedure for isolating (and subsequently cryosectioning) EOMs while preserving the integrity of their original structural organization. Next, we present several useful histological protocols frequently used by us, including: (1) a method for highlighting the general organization of periocular tissue, using the MyoD(Cre) × R26(mTmG) reporter mouse that elegantly distinguishes muscle (MyoD(Cre)-driven GFP(+)) from the non-myogenic constituents (Tomato(+)); (2) analysis by H&E staining, allowing for example, detection of the pathological features of the dystrophin-null phenotype in affected limb and diaphragm muscles that are absent in EOMs; (3) detection of the myogenic progenitors (i.e., satellite cells) in their native position underneath the myofiber basal lamina using Pax7/laminin double immunostaining. The EOM tissue harvesting procedure described here can also be adapted for isolating and studying satellite cells and other cell types. Overall, the methods described in this chapter should provide investigators the necessary tools for entering the EOM research field and contribute to a better understanding of this highly specialized muscle group and its complex micro-anatomy.
Collapse
|
10
|
Stuelsatz P, Shearer A, Li Y, Muir LA, Ieronimakis N, Shen QW, Kirillova I, Yablonka-Reuveni Z. Extraocular muscle satellite cells are high performance myo-engines retaining efficient regenerative capacity in dystrophin deficiency. Dev Biol 2014; 397:31-44. [PMID: 25236433 DOI: 10.1016/j.ydbio.2014.08.035] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 08/29/2014] [Accepted: 08/30/2014] [Indexed: 12/18/2022]
Abstract
Extraocular muscles (EOMs) are highly specialized skeletal muscles that originate from the head mesoderm and control eye movements. EOMs are uniquely spared in Duchenne muscular dystrophy and animal models of dystrophin deficiency. Specific traits of myogenic progenitors may be determinants of this preferential sparing, but very little is known about the myogenic cells in this muscle group. While satellite cells (SCs) have long been recognized as the main source of myogenic cells in adult muscle, most of the knowledge about these cells comes from the prototypic limb muscles. In this study, we show that EOMs, regardless of their distinctive Pax3-negative lineage origin, harbor SCs that share a common signature (Pax7(+), Ki67(-), Nestin-GFP(+), Myf5(nLacZ+), MyoD-positive lineage origin) with their limb and diaphragm somite-derived counterparts, but are remarkably endowed with a high proliferative potential as revealed in cell culture assays. Specifically, we demonstrate that in adult as well as in aging mice, EOM SCs possess a superior expansion capacity, contributing significantly more proliferating, differentiating and renewal progeny than their limb and diaphragm counterparts. These robust growth and renewal properties are maintained by EOM SCs isolated from dystrophin-null (mdx) mice, while SCs from muscles affected by dystrophin deficiency (i.e., limb and diaphragm) expand poorly in vitro. EOM SCs also retain higher performance in cell transplantation assays in which donor cells were engrafted into host mdx limb muscle. Collectively, our study provides a comprehensive picture of EOM myogenic progenitors, showing that while these cells share common hallmarks with the prototypic SCs in somite-derived muscles, they distinctively feature robust growth and renewal capacities that warrant the title of high performance myo-engines and promote consideration of their properties for developing new approaches in cell-based therapy to combat skeletal muscle wasting.
Collapse
Affiliation(s)
- Pascal Stuelsatz
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA, USA
| | - Andrew Shearer
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA, USA
| | - Yunfei Li
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA, USA
| | - Lindsey A Muir
- Program in Molecular and Cellular Biology and Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - Nicholas Ieronimakis
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA
| | - Qingwu W Shen
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA, USA
| | - Irina Kirillova
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA, USA
| | - Zipora Yablonka-Reuveni
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA, USA.
| |
Collapse
|
11
|
Straka H, Fritzsch B, Glover JC. Connecting ears to eye muscles: evolution of a 'simple' reflex arc. BRAIN, BEHAVIOR AND EVOLUTION 2014; 83:162-75. [PMID: 24776996 DOI: 10.1159/000357833] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 12/05/2013] [Indexed: 11/19/2022]
Abstract
Developmental and evolutionary data from vertebrates are beginning to elucidate the origin of the sensorimotor pathway that links gravity and motion detection to image-stabilizing eye movements--the vestibulo-ocular reflex (VOR). Conserved transcription factors coordinate the development of the vertebrate ear into three functional sensory compartments (graviception/translational linear acceleration, angular acceleration and sound perception). These sensory components connect to specific populations of vestibular and auditory projection neurons in the dorsal hindbrain through undetermined molecular mechanisms. In contrast, a molecular basis for the patterning of the vestibular projection neurons is beginning to emerge. These are organized through the actions of rostrocaudally and dorsoventrally restricted transcription factors into a 'hodological mosaic' within which coherent and largely segregated subgroups are specified to project to different targets in the spinal cord and brain stem. A specific set of these regionally diverse vestibular projection neurons functions as the central element that transforms vestibular sensory signals generated by active and passive head and body movements into motor output through the extraocular muscles. The large dynamic range of motion-related sensory signals requires an organization of VOR pathways as parallel, frequency-tuned, hierarchical connections from the sensory periphery to the motor output. We suggest that eyes, ears and functional connections subserving the VOR are vertebrate novelties that evolved into a functionally coherent motor control system in an almost stereotypic organization across vertebrate taxa.
Collapse
Affiliation(s)
- Hans Straka
- Department of Biology II, Ludwig Maximilians University Munich, Planegg, Germany
| | | | | |
Collapse
|
12
|
Abbott WW, Faisal AA. Ultra-low-cost 3D gaze estimation: an intuitive high information throughput compliment to direct brain–machine interfaces. J Neural Eng 2012; 9:046016. [DOI: 10.1088/1741-2560/9/4/046016] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
13
|
Aring E, Ekström AB, Tulinius M, Sjöström A. Ocular motor function in relation to gross motor function in congenital and childhood myotonic dystrophy type 1. Acta Ophthalmol 2012; 90:369-74. [PMID: 20560889 DOI: 10.1111/j.1755-3768.2010.01956.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To assess ocular motor function in congenital and childhood myotonic dystrophy type 1 (DM1) and correlate the results with cytosine-thymine-guanine (CTG) repeat size, severity of the disease, myotonia and skeletal muscle function. METHODS A cross-sectional investigation into strabismus, versions/ductions, saccades, smooth pursuit movements and ptosis was performed on 49 individuals with a confirmed diagnosis of DM1, all diagnosed at <18 years of age and with >40 CTG expansion repeats. The results were correlated with myotonia as well as Hammersmith motor ability scale (HMA). In addition, the ocular results were compared to results from an age and- sex-matched control group. RESULTS Ocular motor abnormalities were seen in 82%; the most frequent findings were altered conjugate eye movements and 'pseudoptosis' while blepharoptosis was rare. Strabismus was most common in the severe congenital subgroup, with a frequency 14 times higher than in the control group. Positive correlations were seen between CTG repeat size and affected eyelids, and between myotonia and affected eyelids; both these findings were most prominent in the mild congenital group. CTG repeat size was also correlated with version/duction defects, and most obviously in the childhood group. Low HMA scores were associated with high occurrence of strabismus and version/duction defects. CONCLUSION Abnormalities of ocular motor function are frequently present. CTG repeat size correlates positively with altered versions/ductions and eyelid pathology. Gross motor dysfunction correlates with strabismus and defect versions/ductions, and eyelid pathology indicates involvement of myotonia.
Collapse
Affiliation(s)
- Eva Aring
- Department of Ophthalmology, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
| | | | | | | |
Collapse
|
14
|
Zhou Y, Gong B, Kaminski HJ. Genomic profiling reveals Pitx2 controls expression of mature extraocular muscle contraction-related genes. Invest Ophthalmol Vis Sci 2012; 53:1821-9. [PMID: 22408009 PMCID: PMC3995565 DOI: 10.1167/iovs.12-9481] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 02/07/2012] [Accepted: 02/07/2012] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To assess the influence of the Pitx2 transcription factor on the global gene expression profile of extraocular muscle (EOM) of mice. METHODS Mice with a conditional knockout of Pitx2, designated Pitx2(Δflox/Δflox) and their control littermates Pitx2(flox/flox), were used. RNA was isolated from EOM obtained at 3, 6, and 12 weeks of age and processed for microarray-based profiling. Pairwise comparisons were performed between mice of the same age and differentially expressed gene lists were generated. Select genes from the profile were validated using real-time quantitative polymerase chain reaction and protein immunoblot. Ultrastructural analysis was performed to evaluate EOM sarcomeric structure. RESULTS The number of differentially expressed genes was relatively small. Eleven upregulated and 23 downregulated transcripts were identified common to all three age groups in the Pitx2-deficient extraocular muscle compared with littermate controls. These fell into a range of categories including muscle-specific structural genes, transcription factors, and ion channels. The differentially expressed genes were primarily related to muscle contraction. We verified by protein and ultrastructural analysis that myomesin 2 was expressed in the Pitx2-deficient mice, and this was associated with development of M lines evident in their orbital region. CONCLUSIONS The global transcript expression analysis uncovered that Pitx2 primarily regulates a relatively select number of genes associated with muscle contraction. Pitx2 loss led to the development of M line structures, a feature more typical of other skeletal muscle.
Collapse
Affiliation(s)
- Yuefang Zhou
- From the Department of Neurology and Psychiatry, Saint Louis University, St. Louis, Missouri;the Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri; andthe Department of Neurology, Department of Pharmacology and Physiology, George Washington University, Washington, DC
| | - Bendi Gong
- From the Department of Neurology and Psychiatry, Saint Louis University, St. Louis, Missouri;the Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri; andthe Department of Neurology, Department of Pharmacology and Physiology, George Washington University, Washington, DC
| | - Henry J. Kaminski
- From the Department of Neurology and Psychiatry, Saint Louis University, St. Louis, Missouri;the Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri; andthe Department of Neurology, Department of Pharmacology and Physiology, George Washington University, Washington, DC
| |
Collapse
|
15
|
Gowing G, Svendsen CN. Stem cell transplantation for motor neuron disease: current approaches and future perspectives. Neurotherapeutics 2011; 8:591-606. [PMID: 21904789 PMCID: PMC3210365 DOI: 10.1007/s13311-011-0068-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Motor neuron degeneration leading to muscle atrophy and death is a pathological hallmark of disorders, such as amyotrophic lateral sclerosis or spinal muscular atrophy. No effective treatment is available for these devastating diseases. At present, cell-based therapies targeting motor neuron replacement, support, or as a vehicle for the delivery of neuroprotective molecules are being investigated. Although many challenges and questions remain, the beneficial effects observed following transplantation therapy in animal models of motor neuron disease has sparked hope and a number of clinical trials. Here, we provide a comprehensive review of cell-based therapeutics for motor neuron disorders, with a particular emphasis on amyotrophic lateral sclerosis.
Collapse
Affiliation(s)
- Genevieve Gowing
- Regenerative Medicine Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048 USA
| | - Clive N. Svendsen
- Regenerative Medicine Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048 USA
| |
Collapse
|
16
|
Kushner BJ. Incomitant strabismus: does extraocular muscle form denote function? THE AMERICAN ORTHOPTIC JOURNAL 2011; 61:88-102. [PMID: 21856877 DOI: 10.3368/aoj.61.1.88] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The paradigm that an underacting extraocular muscle (EOM) is always atrophic or hypoplastic, and an overacting EOM should always be enlarged, leads to inconsistencies with clinical observations. It is inconsistent with the findings of normal extraocular muscle diameters in patients with apparent superior oblique muscle palsy, "overacting" inferior oblique muscles, and the superior rectus muscle overaction / contracture syndrome, among other clinical entities. These inconsistencies can be reconciled if one accepts the possibility that EOM contractile activity may reflect a change in neural input to an anatomically normal muscle, and / or that muscle contractile activity may be altered by a shift in fiber type and distribution within a normal-sized muscle. This remodeling may occur as a result of vergence adaptation or any change in neural stimulus to the muscle. There is substantial evidence to suggest that both these theoretical possibilities may likely occur.
Collapse
Affiliation(s)
- Burton J Kushner
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin 53705, USA.
| |
Collapse
|
17
|
Yu-Wai-Man C, Petheram K, Davidson AW, Williams T, Griffiths PG. A Supranuclear Disorder of Ocular Motility as a Rare Initial Presentation of Motor Neurone Disease. Neuroophthalmology 2011; 35:38-39. [DOI: 10.3109/01658107.2010.518333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 05/31/2010] [Accepted: 07/21/2010] [Indexed: 11/13/2022] Open
|
18
|
Abstract
Although often considered as a group, spinal motor neurons are highly diverse in terms of their morphology, connectivity, and functional properties and differ significantly in their response to disease. Recent studies of motor neuron diversity have clarified developmental mechanisms and provided novel insights into neurodegeneration in amyotrophic lateral sclerosis (ALS). Motor neurons of different classes and subtypes--fast/slow, alpha/gamma--are grouped together into motor pools, each of which innervates a single skeletal muscle. Distinct mechanisms regulate their development. For example, glial cell line-derived neurotrophic factor (GDNF) has effects that are pool-specific on motor neuron connectivity, column-specific on axonal growth, and subtype-specific on survival. In multiple degenerative contexts including ALS, spinal muscular atrophy (SMA), and aging, fast-fatigable (FF) motor units degenerate early, whereas motor neurons innervating slow muscles and those involved in eye movement and pelvic sphincter control are strikingly preserved. Extrinsic and intrinsic mechanisms that confer resistance represent promising therapeutic targets in these currently incurable diseases.
Collapse
Affiliation(s)
- Kevin C Kanning
- Department of Pathology, Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA
| | | | | |
Collapse
|
19
|
Abstract
The extraocular muscles (EOMs) are a unique group of muscles that are anatomically and physiologically distinct from other muscles. We and others have shown that EOMs have a unique transcriptome and proteome. Here we investigated the expression pattern of microRNAs (miRNAs), as they may play a role in generating the unique EOM allotype. We isolated RNA and screened LC Sciences miRNA microarrays covering the sequences of miRBase 10.0 to define the microRNAome of normal mouse EOM and tibialis anterior (TA) limb muscle. Seventy-four miRNAs were found to be differentially regulated (P value <0.05) of which 31 (14 upregulated, 17 downregulated) were differentially regulated at signal strength >500. Muscle-specific miRNAs miR-206 and miR-499 were upregulated and miR-1, miR-133a, and miR-133b were downregulated in EOM. Quantitative PCR (qPCR) analysis was used to validate the differential expression. Bioinformatic tools were used to identify potential miRNA-mRNA-protein interactions and integrate data with previous transcriptome and proteomic profiling data. Luciferase assays using cotransfection of precursor miRNAs with reporter constructs containing the 3'-untranslated region of predicted target genes were used to validate targeting by identified miRNAs. The definition of the EOM microRNAome complements existing transcriptome and proteome data about the molecular makeup of EOM and provides further insight into regulation of muscle genes. These data will also help to further explain the unique EOM muscle allotype and its differential sensitivity to diseases such as Duchenne muscular dystrophy and may assist in development of therapeutic strategies.
Collapse
Affiliation(s)
- Ulrike Zeiger
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania, School of Medicine, Philadelphia, Pennsylvania
| | | |
Collapse
|
20
|
Mensink HW, van Doorn PA, Paridaens D. Concurrent Myopathy in Patients with Graves’ Orbitopathy. Orbit 2009; 28:66-70. [PMID: 19229749 DOI: 10.1080/01676830802483157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
21
|
Farrugia ME, Jacob S, Sarrigiannis PG, Kennett RP. Correlating extent of neuromuscular instability with acetylcholine receptor antibodies. Muscle Nerve 2009; 39:489-93. [PMID: 19260064 DOI: 10.1002/mus.21156] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In a retrospective study of 86 patients with myasthenia gravis (MG), we correlated the acetylcholine receptor (AChR) antibody titers with single-fiber EMG studies to explore whether a relationship exists between these parameters. We found that the AChR antibody titers correlated significantly with the mean of the mean consecutive difference of orbicularis oculi (OO, P<0.0001) and extensor digitorum communis (EDC, P<0.0001). The correlation was found to be stronger in OO. The antibody titers also correlated with the percentage of potential pairs with increased jitter in both muscles and, again, the correlation was more significant in OO (P<0.0001) than in EDC (P=0.001). We speculate that this relationship is stronger in OO than in the limb muscles, because the architectural and immunological differences in the motor unit render OO more vulnerable and sensitive to disturbances in neuromuscular transmission.
Collapse
Affiliation(s)
- Maria E Farrugia
- Department of Clinical Neurophysiology, West Wing, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK.
| | | | | | | |
Collapse
|
22
|
van Zundert B, Peuscher MH, Hynynen M, Chen A, Neve RL, Brown RH, Constantine-Paton M, Bellingham MC. Neonatal neuronal circuitry shows hyperexcitable disturbance in a mouse model of the adult-onset neurodegenerative disease amyotrophic lateral sclerosis. J Neurosci 2008; 28:10864-74. [PMID: 18945894 PMCID: PMC3844745 DOI: 10.1523/jneurosci.1340-08.2008] [Citation(s) in RCA: 186] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 08/07/2008] [Accepted: 09/02/2008] [Indexed: 12/13/2022] Open
Abstract
Distinguishing the primary from secondary effects and compensatory mechanisms is of crucial importance in understanding adult-onset neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). Transgenic mice that overexpress the G93A mutation of the human Cu-Zn superoxide dismutase 1 gene (hSOD1(G93A) mice) are a commonly used animal model of ALS. Whole-cell patch-clamp recordings from neurons in acute slice preparations from neonatal wild-type and hSOD1(G93A) mice were made to characterize functional changes in neuronal activity. Hypoglossal motoneurons (HMs) in postnatal day 4 (P4)-P10 hSOD1(G93A) mice displayed hyperexcitability, increased persistent Na(+) current (PC(Na)), and enhanced frequency of spontaneous excitatory and inhibitory transmission, compared with wild-type mice. These functional changes in neuronal activity are the earliest yet reported for the hSOD1(G93A) mouse, and are present 2-3 months before motoneuron degeneration and clinical symptoms appear in these mice. Changes in neuronal activity were not restricted to motoneurons: superior colliculus interneurons also displayed hyperexcitability and synaptic changes (P10-P12). Furthermore, in vivo viral-mediated GFP (green fluorescent protein) overexpression in hSOD1(G93A) HMs revealed precocious dendritic remodeling, and behavioral assays revealed transient neonatal neuromotor deficits compared with controls. These findings underscore the widespread and early onset of abnormal neural activity in this mouse model of the adult neurodegenerative disease ALS, and suggest that suppression of PC(Na) and hyperexcitability early in life might be one way to mitigate or prevent cell death in the adult CNS.
Collapse
Affiliation(s)
- Brigitte van Zundert
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts 02429
| | - Marieke H. Peuscher
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Meri Hynynen
- Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts 02429
| | - Adam Chen
- Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts 02429
| | - Rachael L. Neve
- Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, Massachusetts 02178, and
| | - Robert H. Brown
- Day Laboratory for Neuromuscular Research, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts 02429
| | - Martha Constantine-Paton
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Mark C. Bellingham
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| |
Collapse
|
23
|
Moon SY, Lee BH, Seo SW, Kang SJ, Na DL. Slow vertical saccades in the frontotemporal dementia with motor neuron disease. J Neurol 2008; 255:1337-43. [PMID: 18825435 DOI: 10.1007/s00415-008-0890-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Revised: 12/10/2007] [Accepted: 02/01/2008] [Indexed: 02/02/2023]
Abstract
BACKGROUND Ocular motor abnormalities play an important role in differential diagnoses of Pick complex diseases. OBJECTIVES We evaluated how frequently supranuclear vertical saccadic impairment was observed in patients with frontotemporal dementia with motor neuron disease (FTD-MND). In addition, we tried to characterize their vertical saccadic abnormalities. MATERIALS AND METHODS Eleven patients with FTD-MND were recruited. Supranuclear vertical saccadic impairment on gross examination was defined as slow saccades with or without reduction in the final amplitude of the movement accompanied by intact oculocephalic reflex. We also recorded their saccades in 6 out of 11 patients using 2-dimensional videooculography (VOG). We measured the amplitude and peak velocity of each saccade. RESULTS On bedside examination, supranuclear vertical saccadic impairment was observed in 9 of 11 patients. One of the two remaining patients could not be evaluated due to poor cooperation and the other showed normal saccades. Five of nine patients with ocular abnormalities and one patient with normal saccade on gross examination underwent the VOG studies. The results showed that all the five patients with gross ocular abnormalities, compared with age-matched controls, had slowing of vertical saccades. Three out of five patients also showed slowing even in the large horizontal saccades. CONCLUSIONS Our results showed that slow vertical saccades are common in FTDMND. FTD-MND could be another disease that affects vertical gaze among Pick complex disease. Future pathologic studies are needed to confirm the involvement of the burst neurons in the dorsal midbrain in patients with FTDMND.
Collapse
Affiliation(s)
- S Y Moon
- Dept. of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku, Seoul, 135-710, Korea
| | | | | | | | | |
Collapse
|
24
|
Abstract
BACKGROUND The ocular motility (OM) deficit in myasthenia has not been studied systematically. Anecdotal reports yield no consensus, with the pattern mimicking infranuclear, internuclear or supranuclear disorders. The current study defines the pattern of extra-ocular muscle (EOM) weakness at presentation for a group of newly diagnosed untreated ocular myasthenics (OMG). METHODS Cases referred to one consultant neurologist (RAM) between 1991 and 2001 were reviewed. EOM weaknesses were quantified using an established scoring method in 49 patients with OMG and 49 age- and sex-matched controls, to differentiate age-related changes from those secondary to myasthenia. RESULTS Bilateral and multiple EOM weaknesses were typical. Only 6 cases mimicked isolated cranial nerve palsy. Weakness of the elevator muscles (superior rectus and inferior oblique) was common in both the OMG and control groups, but the amount of weakness was significantly greater for the myasthenia group (p = 0.003). All control subjects had a normal range of depression. EOM weaknesses for the control group were not confined to the older subjects. DISCUSSION This is the first detailed analysis of EOM involvement in ocular myasthenia. The EOM weaknesses for the control group were invariably bilateral and symmetrical, mainly involving the superior recti. The preponderance for involvement of the elevator muscles is discussed.
Collapse
Affiliation(s)
- Marie Cleary
- Orthoptic Department, Gartnavel General Hospital, Glasgow, Scotland, UK.
| | | | | |
Collapse
|
25
|
Kurne A, Arsava EM, Dalkara T. Rapid Response of Myasthenic Ocular Signs to IvIg Treatment. Neuroophthalmology 2008. [DOI: 10.1080/01658100802331653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
|
26
|
Abstract
Extraocular muscle is fundamentally distinct from other skeletal muscles. Here, we review the biological organization of the extraocular muscles with the intent of understanding this novel muscle group in the context of oculomotor system function. The specific objectives of this review are threefold. The first objective is to understand the anatomic arrangement of the extraocular muscles and their compartmental or layered organization in the context of a new concept of orbital mechanics, the active pulley hypothesis. The second objective is to present an integrated view of the morphologic, cellular, and molecular differences between extraocular and the more traditional skeletal muscles. The third objective is to relate recent data from functional and molecular biology studies to the established extraocular muscle fiber types. Developmental mechanisms that may be responsible for the divergence of the eye muscles from a skeletal muscle prototype also are considered. Taken together, a multidisciplinary understanding of extraocular muscle biology in health and disease provides insights into oculomotor system function and malfunction. Moreover, because the eye muscles are selectively involved or spared in a variety of neuromuscular diseases, knowledge of their biology may improve current pathogenic models of and treatments for devastating systemic diseases.
Collapse
Affiliation(s)
- Robert F Spencer
- Department of Anatomy, Medical College of Virginia, Richmond, VA 23298, USA
| | | |
Collapse
|
27
|
Longstreth WT, Meschke JS, Davidson SK, Smoot LM, Smoot JC, Koepsell TD. Hypothesis: a motor neuron toxin produced by a clostridial species residing in gut causes ALS. Med Hypotheses 2005; 64:1153-6. [PMID: 15823706 DOI: 10.1016/j.mehy.2004.07.041] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Accepted: 07/22/2004] [Indexed: 11/28/2022]
Abstract
We hypothesize that a yet-to-be-identified motor neuron toxin produced by a clostridial species causes sporadic amyotrophic lateral sclerosis (ALS) in susceptible individuals. This clostridial species would reside undetected in the gut and chronically produce a toxin that targets the motor system, like the tetanus and botulinum toxins. After gaining access to the lower motor neuron, the toxin would be transported back to the cell body, as occurs with the tetanus toxin, and destroy the lower motor neuron - the essential feature of ALS. Again like the tetanus toxin, some of the toxin would cross to neighboring cells and to the upper motor neuron and similarly destroy these motor neurons. Weakness would relentlessly progress until not enough motor neurons remained to sustain life. If this hypothesis were correct, treatment with appropriate antibiotics or antitoxins might slow or halt progression of disease, and immunization might prevent disease.
Collapse
Affiliation(s)
- W T Longstreth
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA.
| | | | | | | | | | | |
Collapse
|
28
|
Bogacki PA, Borkowska A, Wojtanowska-Bogacka M, Rybakowski JK. Relationship between class I and II HLA antigens in schizophrenia and eye movement disturbances: a preliminary study. Neuropsychobiology 2005; 51:204-10. [PMID: 15870510 DOI: 10.1159/000085595] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The region coding human leukocyte antigen (HLA) on chromosome 6q21 was shown to be associated with both the vulnerability to schizophrenia and presence of eye movement disturbances (EMD). The aim of this preliminary study was to investigate how individual class I and II HLA antigens in schizophrenic patients may be related to schizophrenia and to the intensity of two kinds of EMD: fixation and smooth pursuit. The incidence of HLA antigens was compared between 40 schizophrenic patients (17 male, 23 female) and 198 healthy control subjects (112 male, 86 female). In schizophrenic patients, the intensity of EMD assessed by infrared reflectometry and quantified on a scale from 0 to 3 was correlated with the incidence of HLA antigens. A number of differences regarding HLA antigens were found between schizophrenic patients and healthy subjects. Significant correlation was also obtained between some EMD and a number of HLA antigens. Antigens A24 and A28 were found to occur in different frequencies in schizophrenic patients and healthy control subjects. They also correlated with EMD on the fixation and smooth pursuit tests. The results obtained show an association between HLA antigens and EMD as an endophenotypic marker of schizophrenia, and may add to other findings on susceptibility loci for schizophrenia on chromosome 6p21. A limitation of this study is a small number of investigated patients with schizophrenia.
Collapse
Affiliation(s)
- Przemysław A Bogacki
- Department of Adult Psychiatry, University of Medical Sciences, ul. Szpitalna 27/33, 60-572 Poznań, Poland
| | | | | | | |
Collapse
|
29
|
Fischer MD, Budak MT, Bakay M, Gorospe JR, Kjellgren D, Pedrosa-Domellöf F, Hoffman EP, Khurana TS. Definition of the unique human extraocular muscle allotype by expression profiling. Physiol Genomics 2005; 22:283-91. [PMID: 15855387 DOI: 10.1152/physiolgenomics.00158.2004] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The extraocular muscles (EOMs) are a unique group of specialized muscles that are anatomically and physiologically distinct from other skeletal muscles. Perhaps the most striking characteristic of the EOMs is their differential sensitivity to disease. EOMs are spared in Duchenne's muscular dystrophy (DMD) despite widespread involvement of other skeletal muscles. Conversely, they are early and prominent targets in myasthenia gravis and mitochondrial myopathies. It is unclear how EOMs achieve such specialization or a differential response to diseases; however, this has been attributed to a unique, group-specific pattern of gene expression or "allotype." To begin to address these issues as well as define the human EOM allotype, we analyzed the human EOM transcriptome using oligonucleotide-based expression profiling. Three hundred thirty-eight genes were found to be differentially expressed in EOM compared with quadriceps femoris limb muscle, using a twofold cutoff. Functional characterization revealed expression patterns corresponding to known metabolic and structural properties of EOMs such as expression of EOM-specific myosin heavy chain (MYH13) and high neural, vascular, and mitochondrial content, suggesting that the profiling was sensitive and specific. Genes related to myogenesis, stem cells, and apoptosis were detected at high levels in normal human EOMs, suggesting that efficient and continuous regeneration and/or myogenesis may be a mechanism by which the EOMs remain clinically and pathologically spared in diseases such as DMD. Taken together, this study provides insight into how human EOMs achieve their unique structural, metabolic, and pathophysiological properties.
Collapse
Affiliation(s)
- M Dominik Fischer
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6085, USA
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Yu Wai Man CY, Chinnery PF, Griffiths PG. Extraocular muscles have fundamentally distinct properties that make them selectively vulnerable to certain disorders. Neuromuscul Disord 2005; 15:17-23. [PMID: 15639116 DOI: 10.1016/j.nmd.2004.10.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Revised: 09/22/2004] [Accepted: 10/01/2004] [Indexed: 11/23/2022]
Abstract
While skeletal muscles generally perform specific limited roles, extraocular muscles (EOMs) have to be responsive over a wider dynamic range. As a result, EOMs have fundamentally distinct structural, functional, biochemical and immunological properties compared to other skeletal muscles. While these properties enable high fatigue resistance and the rapid and precise control of extraocular motility, they might also explain why EOMs are selectively involved in certain disorders, such as chronic progressive external ophthalmoplegia (CPEO), myasthenia gravis and Graves' ophthalmopathy. This review first gives an overview of the novel myofibre classification in EOMs and then focuses on those properties that might explain why ophthalmoplegia should be so prominent in these disorders.
Collapse
Affiliation(s)
- C Y Yu Wai Man
- Department of Neurology, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, UK
| | | | | |
Collapse
|
31
|
McClung JR, Cullen KE, Shall MS, Dimitrova DM, Goldberg SJ. Effects of electrode penetrations into the abducens nucleus of the monkey: eye movement recordings and histopathological evaluation of the nuclei and lateral rectus muscles. Exp Brain Res 2004; 158:180-8. [PMID: 15221166 DOI: 10.1007/s00221-004-1892-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Accepted: 01/06/2004] [Indexed: 11/30/2022]
Abstract
Two adult rhesus monkeys that had undergone 2 years of electrode penetrations into their abducens and vestibular nuclei, for chronic eye movement studies, were examined histologically. An analysis of their VIth nucleus neurons and lateral rectus muscles revealed the following. Twenty-two percent of the large neurons (approximately 30 microm in diameter), on average, were missing and extensive neuropil disruption and gliosis was evident in the experimental side abducens nuclei as compared with the control side in each animal. While the lateral rectus muscles showed small, but inconsistent, changes in total fiber number, the muscle fiber diameters were altered, leading to a more homogenous muscle and making the typical orbital and global subdivisions of the muscle less distinct. Eye movement records from before and after the electrophysiological studies were comparable. We discuss how the complex architecture of the extraocular muscles as well as the possibility of polyneuronal innervation of single muscle fibers could explain our results.
Collapse
Affiliation(s)
- J R McClung
- Department of Anatomy & Neurobiology, POB 980709, Virginia Commonwealth University, 1101 E. Marshall St., Richmond, VA 23298, USA
| | | | | | | | | |
Collapse
|
32
|
Vincent A. Antibody-mediated disorders of neuromuscular transmission. SUPPLEMENTS TO CLINICAL NEUROPHYSIOLOGY 2004; 57:147-58. [PMID: 16106615 DOI: 10.1016/s1567-424x(09)70352-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Angela Vincent
- Neurosciences Group, Department of Clinical Neurology, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, UK.
| |
Collapse
|
33
|
Porter JD, Merriam AP, Gong B, Kasturi S, Zhou X, Hauser KF, Andrade FH, Cheng G. Postnatal suppression of myomesin, muscle creatine kinase and the M-line in rat extraocular muscle. J Exp Biol 2003; 206:3101-12. [PMID: 12878677 DOI: 10.1242/jeb.00511] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The M-line and its associated creatine kinase (CK) M-isoform (CK-M) are ubiquitous features of skeletal and cardiac muscle. The M-line maintains myosin myofilaments in register, links the contractile apparatus to the cytoskeleton for external force transfer and localizes CK-based energy storage and transfer to the site of highest ATP demand. We establish here that the muscle group responsible for movements of the eye, extraocular muscle (EOM), is divergent from other striated muscles in lacking both an M-line and its associated CK-M. Although an M-line forms during myogenesis, both in vivo and in vitro, it is actively repressed after birth. Transcripts of the major M-line structural proteins, myomesin 1 and myomesin 2, follow the same pattern of postnatal downregulation, while the embryonic heart-specific EH-myomesin 1 transcript is expressed early and retained in adult eye muscle. By immunocytochemistry, myomesin protein is absent from adult EOM sarcomeres. M-line suppression does not occur in organotypic co-culture with oculomotor motoneurons, suggesting that the mechanism for suppression may lie in muscle group-specific activation or workload patterns experienced only in vivo. The M-line is, however, still lost in dark-reared rats, despite the developmental delay this paradigm produces in the visuomotor system and EOMs. EOM was low in all CK isoform transcripts except for the sarcomeric mitochondrial (Ckmt2) isoform. Total CK enzyme activity of EOM was one-third that of hindlimb muscle. These findings are singularly unique among fast-twitch skeletal muscles. Since EOM exhibits isoform diversity for other sarcomeric proteins, the M-line/CK-M divergence probably represents a key physiological adaptation for the unique energetics and functional demands placed on this muscle group in voluntary and reflexive eye movements.
Collapse
Affiliation(s)
- John D Porter
- Department of Ophthalmology, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, OH 44106, USA.
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Kaminski HJ, Li Z, Richmonds C, Ruff RL, Kusner L. Susceptibility of Ocular Tissues to Autoimmune Diseases. Ann N Y Acad Sci 2003; 998:362-74. [PMID: 14592898 DOI: 10.1196/annals.1254.043] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The orbital tissues may form a unique immunological environment, as evidenced by autoimmune disorders that specifically target orbital tissues, particularly myasthenia gravis (MG) and Graves' ophthalmopathy (GO). The reasons for the preferential susceptibility are likely to be multiple, based on the interplay of molecular and physiological properties of extraocular muscles (EOM), the unique requirements of the ocular motor system, and the specific autoimmune pathology. Of general importance, even a minor loss of EOM force generation will sufficiently misalign the visual axes to produce dramatic symptoms, and proprioceptive feedback is limited to overcome such a deficit. Particular to MG, EOM synapses appear susceptible to neuromuscular blockade, the autoimmune pathology differs between ocular and generalized MG patients, and the influence of complement regulatory factors may be less prominent in preventing damage at EOM neuromuscular junctions. GO pathogenesis is poorly understood, but shared epitopes of orbital fibroblasts, EOM, and thyroid could lead to specific autoimmune targeting of these tissues. The differential response of orbital fibroblasts to cytokines may be a key factor in disease development. Greater appreciation of the immunologic environment of orbital tissues may lead to therapies specifically designed for orbital autoimmune diseases.
Collapse
Affiliation(s)
- Henry J Kaminski
- Department of Neurology, Case Western Reserve University, University Hospitals of Cleveland, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio 44106, USA.
| | | | | | | | | |
Collapse
|