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The Physiology of Idiopathic Dystonia
- C.D. Marsden, John C. Rothwell
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- Journal:
- Canadian Journal of Neurological Sciences / Volume 14 / Issue S3 / August 1987
- Published online by Cambridge University Press:
- 05 January 2016, pp. 521-527
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Dystonia is mysterious and its pathophysiology is uncertain. The fundamental motor abnormality is an abnormality of muscle command signals, such that the wrong agonists may be activated for too long, there is abnormal co-contraction of agonist and antagonists, and there is excessive and misdirected action of synergists and postural fixators. The result is action dystonia. In addition, muscle spasms may occur spontaneously. The peripheral motor apparatus, the corticomotoneurone pathway, and (as far as is known) the proprioceptive feedback machinery, are all intact in primary dystonia. However, a defect of interneuronal machinery has been identified in both the brainstem and spinal cord. In blepharospasm there is hyperexcitability of the lower brainstem interneurones responsible for the R2 component of the blink reflex. In the dystonic arm there is loss of the later phases of la reciprocal inhibition from extensors to flexors. Both deficits may be due to loss of normal basal ganglia inputs onto interneurones. The known sites of focal lesions that may cause symptomatic dystonia all impair basal ganglia output. However, whether such abnormal interneuronal function is sufficient to explain dystonia is not known. Among many unanswered questions are 1) are the cortical instructions for movement specified correctly, and 2) what is responsible for the spontaneous dystonic spasms?
Contributors
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- By DeAnna L. Adkins, Samir Belagaje, S. Thomas Carmichael, Alex R. Carter, John Chae, François Chollet, Michael Chopp, Leonardo G. Cohen, Maurizio Corbetta, Steven C. Cramer, Rick M. Dijkhuizen, Megan Farrell, Seth P. Finklestein, Leigh R. Hochberg, Barbro B Johansson, Theresa A. Jones, Brett Kissela, Jeffrey A. Kleim, Bryan Kolb, J. Leigh Leasure, Yi Li, Isabelle Loubinoux, Andreas Luft, Randolph J. Nudo, Stephen J. Page, Thomas Platz, Valerie M. Pomeroy, David J. Reinkensmeyer, JingMei Ren, J. C. Rothwell, Dorothee Saur, Timothy Schallert, Gottfried Schlaug, Susan Schwerin, Rüdiger J. Seitz, Gordon L. Shulman, O. Swayne, P. Talelli, G. Campbell Teskey, Maurits P. A. van Meer, Nick S. Ward, Cornelius Weiller, Carolee J. Winstein, Steven L. Wolf
- Edited by Steven C. Cramer, University of California, Irvine, Randolph J. Nudo, Kansas University Medical Center
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- Brain Repair After Stroke
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- 10 November 2010
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- 28 October 2010, pp viii-x
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- By Rose Teteki Abbey, K. C. Abraham, David Tuesday Adamo, LeRoy H. Aden, Efrain Agosto, Victor Aguilan, Gillian T. W. Ahlgren, Charanjit Kaur AjitSingh, Dorothy B E A Akoto, Giuseppe Alberigo, Daniel E. Albrecht, Ruth Albrecht, Daniel O. Aleshire, Urs Altermatt, Anand Amaladass, Michael Amaladoss, James N. Amanze, Lesley G. Anderson, Thomas C. Anderson, Victor Anderson, Hope S. Antone, María Pilar Aquino, Paula Arai, Victorio Araya Guillén, S. Wesley Ariarajah, Ellen T. Armour, Brett Gregory Armstrong, Atsuhiro Asano, Naim Stifan Ateek, Mahmoud Ayoub, John Alembillah Azumah, Mercedes L. García Bachmann, Irena Backus, J. Wayne Baker, Mieke Bal, Lewis V. Baldwin, William Barbieri, António Barbosa da Silva, David Basinger, Bolaji Olukemi Bateye, Oswald Bayer, Daniel H. Bays, Rosalie Beck, Nancy Elizabeth Bedford, Guy-Thomas Bedouelle, Chorbishop Seely Beggiani, Wolfgang Behringer, Christopher M. Bellitto, Byard Bennett, Harold V. Bennett, Teresa Berger, Miguel A. Bernad, Henley Bernard, Alan E. Bernstein, Jon L. Berquist, Johannes Beutler, Ana María Bidegain, Matthew P. Binkewicz, Jennifer Bird, Joseph Blenkinsopp, Dmytro Bondarenko, Paulo Bonfatti, Riet en Pim Bons-Storm, Jessica A. Boon, Marcus J. Borg, Mark Bosco, Peter C. Bouteneff, François Bovon, William D. Bowman, Paul S. Boyer, David Brakke, Richard E. Brantley, Marcus Braybrooke, Ian Breward, Ênio José da Costa Brito, Jewel Spears Brooker, Johannes Brosseder, Nicholas Canfield Read Brown, Robert F. Brown, Pamela K. Brubaker, Walter Brueggemann, Bishop Colin O. Buchanan, Stanley M. Burgess, Amy Nelson Burnett, J. Patout Burns, David B. Burrell, David Buttrick, James P. Byrd, Lavinia Byrne, Gerado Caetano, Marcos Caldas, Alkiviadis Calivas, William J. Callahan, Salvatore Calomino, Euan K. Cameron, William S. Campbell, Marcelo Ayres Camurça, Daniel F. Caner, Paul E. Capetz, Carlos F. Cardoza-Orlandi, Patrick W. Carey, Barbara Carvill, Hal Cauthron, Subhadra Mitra Channa, Mark D. Chapman, James H. Charlesworth, Kenneth R. Chase, Chen Zemin, Luciano Chianeque, Philip Chia Phin Yin, Francisca H. Chimhanda, Daniel Chiquete, John T. Chirban, Soobin Choi, Robert Choquette, Mita Choudhury, Gerald Christianson, John Chryssavgis, Sejong Chun, Esther Chung-Kim, Charles M. A. Clark, Elizabeth A. Clark, Sathianathan Clarke, Fred Cloud, John B. Cobb, W. Owen Cole, John A Coleman, John J. Collins, Sylvia Collins-Mayo, Paul K. Conkin, Beth A. Conklin, Sean Connolly, Demetrios J. Constantelos, Michael A. Conway, Paula M. Cooey, Austin Cooper, Michael L. Cooper-White, Pamela Cooper-White, L. William Countryman, Sérgio Coutinho, Pamela Couture, Shannon Craigo-Snell, James L. Crenshaw, David Crowner, Humberto Horacio Cucchetti, Lawrence S. Cunningham, Elizabeth Mason Currier, Emmanuel Cutrone, Mary L. Daniel, David D. Daniels, Robert Darden, Rolf Darge, Isaiah Dau, Jeffry C. Davis, Jane Dawson, Valentin Dedji, John W. de Gruchy, Paul DeHart, Wendy J. Deichmann Edwards, Miguel A. De La Torre, George E. Demacopoulos, Thomas de Mayo, Leah DeVun, Beatriz de Vasconcellos Dias, Dennis C. Dickerson, John M. Dillon, Luis Miguel Donatello, Igor Dorfmann-Lazarev, Susanna Drake, Jonathan A. Draper, N. Dreher Martin, Otto Dreydoppel, Angelyn Dries, A. J. Droge, Francis X. D'Sa, Marilyn Dunn, Nicole Wilkinson Duran, Rifaat Ebied, Mark J. Edwards, William H. Edwards, Leonard H. Ehrlich, Nancy L. Eiesland, Martin Elbel, J. Harold Ellens, Stephen Ellingson, Marvin M. Ellison, Robert Ellsberg, Jean Bethke Elshtain, Eldon Jay Epp, Peter C. Erb, Tassilo Erhardt, Maria Erling, Noel Leo Erskine, Gillian R. Evans, Virginia Fabella, Michael A. Fahey, Edward Farley, Margaret A. Farley, Wendy Farley, Robert Fastiggi, Seena Fazel, Duncan S. Ferguson, Helwar Figueroa, Paul Corby Finney, Kyriaki Karidoyanes FitzGerald, Thomas E. FitzGerald, John R. Fitzmier, Marie Therese Flanagan, Sabina Flanagan, Claude Flipo, Ronald B. Flowers, Carole Fontaine, David Ford, Mary Ford, Stephanie A. Ford, Jim Forest, William Franke, Robert M. Franklin, Ruth Franzén, Edward H. Friedman, Samuel Frouisou, Lorelei F. Fuchs, Jojo M. Fung, Inger Furseth, Richard R. Gaillardetz, Brandon Gallaher, China Galland, Mark Galli, Ismael García, Tharscisse Gatwa, Jean-Marie Gaudeul, Luis María Gavilanes del Castillo, Pavel L. Gavrilyuk, Volney P. Gay, Metropolitan Athanasios Geevargis, Kondothra M. George, Mary Gerhart, Simon Gikandi, Maurice Gilbert, Michael J. Gillgannon, Verónica Giménez Beliveau, Terryl Givens, Beth Glazier-McDonald, Philip Gleason, Menghun Goh, Brian Golding, Bishop Hilario M. Gomez, Michelle A. Gonzalez, Donald K. Gorrell, Roy Gottfried, Tamara Grdzelidze, Joel B. Green, Niels Henrik Gregersen, Cristina Grenholm, Herbert Griffiths, Eric W. Gritsch, Erich S. Gruen, Christoffer H. Grundmann, Paul H. Gundani, Jon P. Gunnemann, Petre Guran, Vidar L. Haanes, Jeremiah M. 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Yee, Viktor Yelensky, Yeo Khiok-Khng, Gustav K. K. Yeung, Angela Yiu, Amos Yong, Yong Ting Jin, You Bin, Youhanna Nessim Youssef, Eliana Yunes, Robert Michael Zaller, Valarie H. Ziegler, Barbara Brown Zikmund, Joyce Ann Zimmerman, Aurora Zlotnik, Zhuo Xinping
- Edited by Daniel Patte, Vanderbilt University, Tennessee
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- The Cambridge Dictionary of Christianity
- Published online:
- 05 August 2012
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- 20 September 2010, pp xi-xliv
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10 - Saccadic chronostasis and the continuity of subjective temporal experience across eye movements
- from Part II - Temporal phenomena: perception
- Edited by Romi Nijhawan, University of Sussex, Beena Khurana, University of Sussex
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- Space and Time in Perception and Action
- Published online:
- 05 October 2010
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- 25 March 2010, pp 149-163
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Summary
Summary
The term “saccadic chronostasis” refers to the subjective temporal lengthening of a visual stimulus perceived following a saccadic eye movement. In this chapter, we discuss our preferred account of the illusion, which posits that the onset of the postsaccadic stimulus is antedated to a moment just prior to movement initiation, and review supporting evidence that illustrates key characteristics of the illusion, including its dependency on saccade extent. We conclude with a brief discussion of other examples of biased time perception that have been linked to saccadic chronostasis.
Introduction
When people make a saccadic eye movement to fixate a new visual target, they overestimate the duration for which that target is perceived (Yarrow et al. 2001). This illusion, which we have called saccadic chronostasis, has been demonstrated using the following basic procedure. Subjects make a saccade to a target that changes form or color during the saccade. They judge the duration of the new target stimulus relative to subsequently presented reference stimuli, and these judgments are used to determine a point of subjective equality (PSE; the point at which the target and reference stimuli are perceived to have identical durations). This procedure is schematized in Fig. 10.1. The same task performed while fixating forms a control. Reduced PSEs in saccadic conditions compared to control fixation conditions are a gauge of the temporal overestimation of the postsaccadic stimulus.
6 - Transcranial magnetic stimulation investigations of reaching and grasping movements
- Edited by Dennis A. Nowak, Joachim Hermsdörfer
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- Sensorimotor Control of Grasping
- Published online:
- 23 December 2009
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- 25 June 2009, pp 72-83
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Summary
Summary
Transcranial magnetic stimulation (TMS) has emerged as a suitable technique to investigate the network of cortical areas involved in human grasp/reach movements. Applied over the primary motor cortex (M1), TMS reveals the pattern of activation of different muscles during complex reaching-to-grasp tasks. Repetitive TMS (rTMS) used to induce “virtual lesions” of other cortical areas has allowed investigation of other cortical structures such as the ventral premotor cortex (PMv), dorsal premotor cortex (PMd) and the anterior intraparietal sulcus (aIPS). Each of these appears to contribute to specific aspects of reaching, grasping and lifting objects. Finally, twin-coil TMS studies can illustrate the time course of operation of parallel intracortical circuits that mediate functional connectivity between the PMd, PMv, the posterior parietal cortex and the primary motor cortices.
Introduction
The ease with which we can make reach-to-grasp movements conceals a good deal of the underlying complexity of the task. Thus, the target of the reach must be located in space; a decision must be made about the most appropriate type and orientation of grasp according to the weight and shape of the object; and the timing of the reaching movement of the arm must be synchronized with the opening of the hand so that the object can be grasped as effectively and quickly as possible (for a review see Castiello, 2005; see also Chapters 2 and 10).
2 - Techniques of transcranial magnetic stimulation
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- By John C. Rothwell, Sobell Department, Institute of Neurology, London, UK
- Edited by Simon Boniface, Ulf Ziemann, Johann Wolfgang Goethe-Universität Frankfurt
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- Book:
- Plasticity in the Human Nervous System
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- 12 August 2009
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- 15 May 2003, pp 26-61
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Summary
In this chapter I discuss the physiology of TMS and describe some of the common techniques that have been applied by those using TMS. I will not describe the details of each method, but outline the general principles and limitations. Most of the work on the basic mechanisms of these techniques has been performed on the motor cortex, where the response to each stimulus is easy to quantify as the amplitude of an MEP response. However, it is thought that the same general principles will apply to stimulation of other areas of cortex, although this may be difficult to prove in practice.
Single pulse transcranial stimulation
Although the majority of studies use TMS to activate the brain, the older method of transcranial electrical stimulation (TES) is still used occasionally. As described below, comparison of the effects of TMS and TES can help distinguish whether an intervention changes cortical excitability at the site of stimulation or at a distant projection target (such as the spinal cord).
Transcranial electrical stimulation of the corticospinal output of the hand area of motor cortex
The corticospinal system forms the largest output of the motor cortex. Experiments in primates have shown that single pulse electrical stimulation of the surface of the exposed cortex activates this output both directly, through depolarization of corticospinal axons in the immediately subcortical white matter, and indirectly via excitatory synaptic input from other cortical neurones (Patton & Amassian, 1954).
10 - Therapeutic uses of rTMS
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- By Chip M. Epstein, Department of Neurology, Emoy Clinic, Atlanta, GA, USA, John C. Rothwell, Sobell Department, Institute of Neurology, London, UK
- Edited by Simon Boniface, Ulf Ziemann, Johann Wolfgang Goethe-Universität Frankfurt
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- Plasticity in the Human Nervous System
- Published online:
- 12 August 2009
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- 15 May 2003, pp 246-263
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Summary
Introduction
The basic rationale for attempting to use rTMS as a therapeutic tool is that it is known to produce effects on cerebral cortex that outlast the stimulus. The assumption is that, in some cases, it may be possible to manipulate these long-term effects either to reverse the pathological processes responsible for the condition, or to change the excitability of remaining healthy systems so that they can compensate for the underlying disturbance. In this chapter we will consider the use of rTMS in psychiatric conditions and in movement disorders. However, before discussing clinical details, we consider the available data about the long-term effects of rTMS in healthy subjects from the standpoint of designing therapeutic trials on patients. In particular, we ask first whether rTMS can ever be targeted accurately enough at specific neural populations to achieve a therapeutic effect and, second, whether the effects it produces will last long enough to be used as a clinical treatment.
Effect on neural circuits, local
Most of our knowledge about the actions of rTMS comes from studies of the motor cortex, although a smaller number of investigations suggest that the basic principles may apply to visual (Boorojerdi et al., 2000) or frontal (Speer et al., 2000) cortex. As summarized in previous chapters, much of this work has described the effects of rTMS in terms of the excitability of the corticospinal output to single pulse TMS.