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SUMMARY:Selective motor control and focal dystonia - Dr. Mark Hallett\, Hu
 man Motor Control Section\, NINDS\, NIH\, Bethesda\, USA
DTSTART:20090929T161500Z
DTEND:20090929T170000Z
UID:TALK18680@talks.cam.ac.uk
CONTACT:Hannah Critchlow
DESCRIPTION:This talk is part of the Cambridge Clinical Neuroscience and M
 ental Health Symposium\, 29th - 30th September 2009 at West Road Concert H
 all. This event is free to attend for cambridge neuroscientists although r
 egistration is required. To register\, and for further information\, pleas
 e visit: http://www.neuroscience.cam.ac.uk/cnmhs/\n\nAbstract: The ability
  to make fine movements\, such as control of individual digits\, is an imp
 ortant skill.  The physiology of the ability is not well known\, and its d
 ysfunction is a prominent component of several movement disorders such as 
 focal dystonia.  The properties of individual corticospinal neurons includ
 e innervation of many spinal alpha-motoneurons\, making the task particula
 rly difficult.  Additionally\, the motor system appears to have a wide spr
 ead activation with even a focal movement.  Hence\, whatever capability th
 ere is for fine control must include some inhibition as well as excitation
 .  The hypothesis has been suggested and largely proven that the motor sys
 tem has a center-surround organization\; so that unwanted movements are in
 hibited as the desired movement is commanded (Sohn and Hallett\, 2004).  T
 his appears to be a cortical process aided by the basal ganglia.  The prec
 ise physiological mechanisms of the surround inhibition have been investig
 ated\, but are not yet completed established.  Patients with focal hand dy
 stonia have difficulties with fine motor control and there is a concomitan
 t dysfunction of the surround inhibition mechanism.  Several intracortical
  circuits have been identified that are malfunctioning and can contribute 
 to the abnormality of surround inhibition (Beck et al.\, 2008).  A feature
  of these circuits are that they are all inhibitory with short latencies. 
  A correlative abnormality has been seen in sensory systems in patients wi
 th focal dystonia.  Behaviorally\, there is a mild abnormality of spatial 
 and temporal discrimination.  The physiology underlying the temporal discr
 imination abnormality is a failure of a short latency inhibitory mechanism
  (Tamura et al.\, 2008).  Hence there might be a similar abnormality of sh
 ort latency inhibition in both motor and sensory function\, suggesting a m
 alfunction of a class of inhibitory interneurons.  Proof of principle stud
 ies have demonstrated that training to improve surround inhibition and sen
 sory discrimination can ameliorate dystonia.  \n\nBiography: Dr. Hallett o
 btained his M.D. at Harvard University and trained in Neurology at Massach
 usetts General Hospital.  He had fellowships in Neurophysiology at the Nat
 ional Institutes of Health and at the Institute of Psychiatry in London.  
 From 1976 to 1984\, Dr. Hallett was the Chief of the Clinical Neurophysiol
 ogy Laboratory at the Brigham and Women's Hospital and Associate Professor
  of Neurology at Harvard Medical School.  From 1984\, he has been at the N
 ational Institute of Neurological Disorders and Stroke where he serves as 
 Chief of the Human Motor Control Section and pursues research on the Physi
 ology of Human Movement Disorders and other problems of Motor Control. He 
 also served as Clinical Director of NINDS until July 2000.  He is past Pre
 sident of the American Association of Electrodiagnostic Medicine and the M
 ovement Disorder Society.  He also served as Vice-President of the America
 n Academy of Neurology.  He is an Associate Editor of Brain and has just t
 aken over as the Editor in Chief of World Neurology.  Currently he also se
 rves on the editorial boards of Clinical Neurophysiology\, Acta Neurologic
 a Scandinavica\, Journal of Clinical Neurophysiology\, Medical Problems of
  Performing Artists\, Annals of Neurology\, The Cerebellum\, NeuroTherapeu
 tics\, and European Neurology.  The main work of his group focuses on the 
 physiology and pathophysiology of movement. Dr. Hallett’s interests in M
 otor Control are wide-ranging\, and include brain plasticity and its relev
 ance to neurological disorders and the pathophysiology of dystonia\, parki
 nsonism\, and myoclonus.  Recently he has become interested in disorders o
 f volition\, including tic and psychogenic movement disorders.  \n
LOCATION:West Road Concert Hall
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