R Chen

Summary

Affiliation: University of Toronto
Country: Canada

Publications

  1. doi request reprint Movement related potentials and oscillatory activities in the human internal globus pallidus during voluntary movements
    Eric W Tsang
    Division of Brain Imaging and Behaviour Systems Neuroscience, Toronto Western Research Institute, University Health Network, Toronto, Canada
    J Neurol Neurosurg Psychiatry 83:91-7. 2012
  2. pmc Bi-directional interhemispheric inhibition during unimanual sustained contractions
    Aimee J Nelson
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University of Toronto, Toronto, Canada
    BMC Neurosci 10:31. 2009
  3. ncbi request reprint Interactions between inhibitory and excitatory circuits in the human motor cortex
    Robert Chen
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
    Exp Brain Res 154:1-10. 2004
  4. ncbi request reprint Organization of ipsilateral excitatory and inhibitory pathways in the human motor cortex
    Robert Chen
    Division of Neurology, Krembil Neuroscience Center and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario M5T 2S8, Canada
    J Neurophysiol 89:1256-64. 2003
  5. ncbi request reprint Plasticity of the human motor system following muscle reconstruction: a magnetic stimulation and functional magnetic resonance imaging study
    Robert Chen
    Division of Neurology, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ont, Canada
    Clin Neurophysiol 114:2434-46. 2003
  6. ncbi request reprint The clinical diagnostic utility of transcranial magnetic stimulation: report of an IFCN committee
    Robert Chen
    Division of Neurology, Toronto Western Research Institute, University of Toronto, 7MC411, Toronto Western Hospital, 399 Bathurst Street, Toronto, Ont, Canada M5T 2S8
    Clin Neurophysiol 119:504-32. 2008
  7. ncbi request reprint Measures of cortical inhibition in health and disease
    Robert Chen
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, ON M5T 2S8, Canada
    Suppl Clin Neurophysiol 57:691-701. 2004
  8. ncbi request reprint Impairment of motor cortex activation and deactivation in Parkinson's disease
    R Chen
    Division of Neurology and The Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario M5T 2S8, Canada
    Clin Neurophysiol 112:600-7. 2001
  9. ncbi request reprint Studies of human motor physiology with transcranial magnetic stimulation
    R Chen
    Division of Neurology and Playfair Neuroscience Unit, Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
    Muscle Nerve Suppl 9:S26-32. 2000
  10. ncbi request reprint Effects of internal globus pallidus stimulation on motor cortex excitability
    R Chen
    Divisions of Neurology, Toronto Western Hospital and Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
    Neurology 56:716-23. 2001

Collaborators

Detail Information

Publications100

  1. doi request reprint Movement related potentials and oscillatory activities in the human internal globus pallidus during voluntary movements
    Eric W Tsang
    Division of Brain Imaging and Behaviour Systems Neuroscience, Toronto Western Research Institute, University Health Network, Toronto, Canada
    J Neurol Neurosurg Psychiatry 83:91-7. 2012
    ..To study internal globus pallidus (GPi) activities and the interactions among the bilateral GPi and motor cortical areas during voluntary movements...
  2. pmc Bi-directional interhemispheric inhibition during unimanual sustained contractions
    Aimee J Nelson
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University of Toronto, Toronto, Canada
    BMC Neurosci 10:31. 2009
    ....
  3. ncbi request reprint Interactions between inhibitory and excitatory circuits in the human motor cortex
    Robert Chen
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
    Exp Brain Res 154:1-10. 2004
    ..It may also be developed into a new way of studying the pathophysiology of diseases and the effects of intervention...
  4. ncbi request reprint Organization of ipsilateral excitatory and inhibitory pathways in the human motor cortex
    Robert Chen
    Division of Neurology, Krembil Neuroscience Center and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario M5T 2S8, Canada
    J Neurophysiol 89:1256-64. 2003
    ..iSP and IHI do not represent the same phenomenon and should be considered complementary measures of ipsilateral inhibition...
  5. ncbi request reprint Plasticity of the human motor system following muscle reconstruction: a magnetic stimulation and functional magnetic resonance imaging study
    Robert Chen
    Division of Neurology, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ont, Canada
    Clin Neurophysiol 114:2434-46. 2003
    ..Although motor system plasticity in response to neuromuscular injury has been documented, few studies have examined recovered and functioning muscles in the human. We examined brain changes in a group of patients who had a muscle transfer...
  6. ncbi request reprint The clinical diagnostic utility of transcranial magnetic stimulation: report of an IFCN committee
    Robert Chen
    Division of Neurology, Toronto Western Research Institute, University of Toronto, 7MC411, Toronto Western Hospital, 399 Bathurst Street, Toronto, Ont, Canada M5T 2S8
    Clin Neurophysiol 119:504-32. 2008
    ..TMS measures have potential clinical utility in cerebellar disease, dementia, facial nerve disorders, movement disorders, stroke, epilepsy, migraine and chronic pain...
  7. ncbi request reprint Measures of cortical inhibition in health and disease
    Robert Chen
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, ON M5T 2S8, Canada
    Suppl Clin Neurophysiol 57:691-701. 2004
  8. ncbi request reprint Impairment of motor cortex activation and deactivation in Parkinson's disease
    R Chen
    Division of Neurology and The Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario M5T 2S8, Canada
    Clin Neurophysiol 112:600-7. 2001
    ..To examine the time course of corticospinal excitability before and after voluntary movement in Parkinson's disease (PD)...
  9. ncbi request reprint Studies of human motor physiology with transcranial magnetic stimulation
    R Chen
    Division of Neurology and Playfair Neuroscience Unit, Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
    Muscle Nerve Suppl 9:S26-32. 2000
    ..Modulation of cortical excitability by rTMS has therapeutic potential in psychiatric and neurological disorders...
  10. ncbi request reprint Effects of internal globus pallidus stimulation on motor cortex excitability
    R Chen
    Divisions of Neurology, Toronto Western Hospital and Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
    Neurology 56:716-23. 2001
    ..Magnetic stimulation studies have revealed abnormalities in several different excitatory and inhibitory circuits in the motor cortex in PD...
  11. ncbi request reprint Changes in cortical excitability with thalamic deep brain stimulation
    G F Molnar
    Division of Neurology, Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    Neurology 64:1913-9. 2005
    ..Both lesioning and DBS of the ventralis intermedius (VIM) nucleus of thalamus improve essential tremor. Although DBS was initially thought to inhibit the target neurons, recent studies suggest that DBS activates neurons...
  12. ncbi request reprint Subthalamic nucleus stimulation modulates afferent inhibition in Parkinson disease
    A Sailer
    Division of Neurology, Krembil Neuroscience Centre and Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
    Neurology 68:356-63. 2007
    ..We hypothesize that subthalamic nucleus (STN) deep brain stimulation (DBS) may correct these deficiencies...
  13. ncbi request reprint Suppression of the motor cortex by magnetic stimulation of the cerebellum
    A D Pinto
    Division of Neurology, Toronto Western Hospital and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    Exp Brain Res 140:505-10. 2001
    ..Activation of contralateral but not ipsilateral proximal arm muscles during arm extension reduced the excitability of the cerebellothalamocortical projections to the hand area of the motor cortex...
  14. pmc Involvement of the human pedunculopontine nucleus region in voluntary movements
    E W Tsang
    Division of Brain Imaging and Behaviour Systems Neuroscience, Toronto Western Hospital, McLaughlin Pavilion, Toronto, Ontario M5T 2S8, Canada
    Neurology 75:950-9. 2010
    ..A greater understanding of how PPNR activities and oscillations are modulated with voluntary movements is crucial to the development of neuromodulation strategies...
  15. ncbi request reprint Cortical reflex myoclonus studied with cortical electrodes
    P Ashby
    Playfair Neuroscience Unit, Toronto Hospital, Western Division, University of Toronto, Ontario, Canada
    Clin Neurophysiol 110:1521-30. 1999
    ..To study the mechanism of cortical reflex myoclonus...
  16. pmc Subthalamic deep brain stimulation at individualized frequencies for Parkinson disease
    E W Tsang
    Division of Brain Imaging and Behaviour Systems Neuroscience, Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
    Neurology 78:1930-8. 2012
    ..We hypothesized that STN deep brain stimulation (DBS) at individualized γ frequencies would improve whereas θ or β frequencies would worsen PD motor signs...
  17. ncbi request reprint Potentials recorded at the scalp by stimulation near the human subthalamic nucleus
    P Ashby
    Movement Disorder Clinic, Toronto Western Hospital, Toronto Western Hospital Research Institute, University of Toronto, Ontario, Canada
    Clin Neurophysiol 112:431-7. 2001
    ....
  18. ncbi request reprint Interactions between short latency afferent inhibition and long interval intracortical inhibition
    Kaviraja Udupa
    Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada
    Exp Brain Res 199:177-83. 2009
    ..Both LICI and SAI decreased with increasing test MEP amplitude. Afferent stimulation that produced SAI decreased LICI. Thus, the present findings suggest that LICI and SAI have inhibitory interactions...
  19. ncbi request reprint Impaired presynaptic inhibition in the motor cortex in Parkinson disease
    J Chu
    Division of Neurology, Department of Medicine, University of Toronto and Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
    Neurology 72:842-9. 2009
    ..The purpose of this study was to test the hypothesis that cortical presynaptic inhibition in Parkinson disease (PD) is impaired...
  20. doi request reprint Control of a neuroprosthesis for grasping using off-line classification of electrocorticographic signals: case study
    C Márquez-Chin
    Rehabilitation Engineering Laboratory, Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M4G 3V9
    Spinal Cord 47:802-8. 2009
    ..Proof of concept study to control a neuroprosthesis for grasping using identification of arm movements from ECoG signals...
  21. ncbi request reprint Mechanism of the silent period following transcranial magnetic stimulation. Evidence from epidural recordings
    R Chen
    Division of Neurology and Playfair Neuroscience Unit, Toronto Western Hospital, University Health Network, University of Toronto, Ontario, Canada
    Exp Brain Res 128:539-42. 1999
    ..Our findings suggest that the early part of the SP is mainly due to spinal mechanisms, while the late part of the SP is related to reduced motor cortex excitability...
  22. pmc Impaired interhemispheric inhibition in writer's cramp
    A J Nelson
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
    Neurology 75:441-7. 2010
    ..Inhibition from the opposite hemisphere, known as interhemispheric inhibition (IHI), was studied bidirectionally in 7 right-handed patients with writer's cramp (WC) and age-matched healthy controls in a cross-sectional physiologic study...
  23. pmc Interactions between two different inhibitory systems in the human motor cortex
    T D Sanger
    Division of Neurology, Toronto Western Hospital and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    J Physiol 530:307-17. 2001
    ..Testing of SICI in the presence of LICI may be a non-invasive way of evaluating inhibitory interactions in the human motor cortex...
  24. ncbi request reprint Thalamic deep brain stimulation activates the cerebellothalamocortical pathway
    G F Molnar
    Division of Neurology, Krembil Neuroscience Centre and Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
    Neurology 63:907-9. 2004
    ..With DBS turned off, excitability of the CTC pathway was reduced. Turning DBS on resulted in facilitation of the CTC pathway. Therefore, thalamic DBS appears to activate rather than inhibit the target area...
  25. ncbi request reprint Effects of subthalamic nucleus stimulation on motor cortex excitability in Parkinson's disease
    D Cunic
    Division of Neurology, Toronto Western Hospital and Research Institute, University Health Network, University of Toronto, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8
    Neurology 58:1665-72. 2002
    ..These include motor evoked potential (MEP) recruitment curve, silent period duration (SP), short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), and long-interval intracortical inhibition (LICI)...
  26. ncbi request reprint Changes in motor cortex excitability with stimulation of anterior thalamus in epilepsy
    G F Molnar
    Division of Neurology, Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
    Neurology 66:566-71. 2006
    ..Different classes of antiepileptic drugs (AEDs) have distinct effects on the excitatory and inhibitory circuits in the motor cortex, which can be studied noninvasively by transcranial magnetic stimulation (TMS)...
  27. pmc The effects of inhibitory and facilitatory intracortical circuits on interhemispheric inhibition in the human motor cortex
    Hubert Lee
    Division of Neurology, Krembil Neuroscience Centre and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    J Physiol 580:1021-32. 2007
    ..SICI and LICI produce more global inhibition with similar effects on the transcallosal and descending corticospinal circuits...
  28. doi request reprint Palliative care for advanced Parkinson disease: an interdisciplinary clinic and new scale, the ESAS-PD
    Janis M Miyasaki
    The Palliative Program for Parkinson Disease and Related Disorders, The Morton and Gloria Shulman Movement Disorders Centre, Toronto Western Hospital, University of Toronto, Canada
    Parkinsonism Relat Disord 18:S6-9. 2012
    ..Palliative care concepts were applied to a group of advanced Parkinson disease (PD) patients in a dedicated Palliative Care Clinic...
  29. ncbi request reprint Involvement of the human subthalamic nucleus in movement preparation
    G Paradiso
    Division of Neurology, University of Toronto, Krembil Neuroscience Centre and Toronto Western Research Institute, Ontario, Canada
    Neurology 61:1538-45. 2003
    ..The subthalamic nucleus (STN) is particularly suited to play a role in movement preparation because it receives direct input from the supplementary motor area through the corticosubthalamic pathway...
  30. ncbi request reprint Observation-execution matching system for speech: a magnetic stimulation study
    M Sundara
    School of Communication Sciences and Disorders, McGill University, Toronto, Ontario, Canada
    Neuroreport 12:1341-4. 2001
    ..The findings suggest that the OEM system may be modality specific. It may be involved in action recognition in the visual modality, but is not responsible for perception of simple items of sound...
  31. doi request reprint Increased cortical inhibition in persons with schizophrenia treated with clozapine
    Zafiris J Daskalakis
    Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada
    J Psychopharmacol 22:203-9. 2008
    ..Our results also confirm previous findings suggesting that deficits in CI are related to the severity of psychotic symptoms in persons with schizophrenia...
  32. doi request reprint Reversal of cortical reorganization in human primary motor cortex following thumb reconstruction
    Zhen Ni
    Division of Neurology, Krembil Neuroscience Centre and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    J Neurophysiol 103:65-73. 2010
    ..We conclude that chronic reorganization occurring in the M1 after amputation can be reversed by reconstruction of the lost body part...
  33. pmc Exploring the connectivity between the cerebellum and motor cortex in humans
    Zafiris J Daskalakis
    Schizophrenia Program, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
    J Physiol 557:689-700. 2004
    ..The third experiment showed that the interaction between CBI and LICI reduced CBI. Collectively, these findings suggest that cerebellar stimulation results in changes to both inhibitory and excitatory neurones in the human motor cortex...
  34. pmc Effects of peripheral sensory input on cortical inhibition in humans
    Alexandra Sailer
    Division of Neurology, Toronto Western Hospital University Health Network, University of Toronto, Ontario, Canada M5T 2S8
    J Physiol 544:617-29. 2002
    ..We conclude that MNSI is mediated by circuits distinct from those mediating LICI or SICI. The MNSI circuits seem to have an inhibitory interaction with the LICI circuits, whereas the SICI and MNSI circuits do not seem to interact...
  35. ncbi request reprint Evidence for excessive frontal evoked gamma oscillatory activity in schizophrenia during working memory
    M S Barr
    Schizophrenia Program, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
    Schizophr Res 121:146-52. 2010
    ..These findings may provide important insights into the pathophysiology underlying WM deficits, its relationship to negative symptoms and may represent a potential neurobiological marker for cognitive enhancing strategies in SCZ...
  36. ncbi request reprint Evidence for impaired long-term potentiation in schizophrenia and its relationship to motor skill learning
    Marina V Frantseva
    Schizophrenia Program, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
    Cereb Cortex 18:990-6. 2008
    ..These data provide evidence for disrupted LTP in SCZ, whereas the association between LTP with motor skill learning suggests that the deficits in learning and memory in SCZ may be mediated through disordered LTP...
  37. pmc Short interval intracortical inhibition and facilitation during the silent period in human
    Zhen Ni
    Division of Neurology, Krembil Neuroscience Centre, University of Toronto, Toronto, Ontario, Canada
    J Physiol 583:971-82. 2007
    ..ICF increased at higher CS intensity. We conclude that SICI is suppressed and ICF is facilitated during the SP and the effects are separate from the interruption of voluntary drive...
  38. doi request reprint Long-interval cortical inhibition from the dorsolateral prefrontal cortex: a TMS-EEG study
    Zafiris J Daskalakis
    Schizophrenia Program, Department of Psychiatry, Centre for Addiction and Mental Health, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
    Neuropsychopharmacology 33:2860-9. 2008
    ..These data suggest that CI can be recorded by combining TMS with EEG and may facilitate future research attempting to ascertain the role of CI in the pathophysiology of several neurological and psychiatric disorders...
  39. ncbi request reprint Motor cortex plasticity in Parkinson's disease and levodopa-induced dyskinesias
    Francesca Morgante
    Division of Neurology and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    Brain 129:1059-69. 2006
    ..Abnormal synaptic plasticity in the motor cortex may play a role in the development of LID...
  40. pmc Interactions between long latency afferent inhibition and interhemispheric inhibitions in the human motor cortex
    Sadiya Kukaswadia
    Division of Neurology, Krembil Neuroscience Centre and Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
    J Physiol 563:915-24. 2005
    ..We conclude that LAI and IHI10 do not directly inhibit each other but LAI probably inhibits IHI40. LICI is more likely to be related to IHI40 than to IHI10...
  41. ncbi request reprint Intraoperative recording of the very fast oscillatory activities evoked by median nerve stimulation in the human thalamus
    R Hanajima
    Toronto Western Research Institute, University Health Network, Toronto, Canada
    Suppl Clin Neurophysiol 59:121-6. 2006
  42. ncbi request reprint Low-frequency repetitive transcranial magnetic stimulation for treatment of levodopa-induced dyskinesias
    A Wagle-Shukla
    Division of Neurology, Krembil Neuroscience Centre, Toronto Western Hospital, University Health Network, University of Toronto, Ontario, Canada
    Neurology 68:704-5. 2007
  43. doi request reprint Cortical plasticity following nerve transfer in the upper extremity
    Dimitri J Anastakis
    Division of Plastic Surgery, University of Toronto, 399 Bathurst Street, East Wing 2, Toronto, Ontario Canada M5G 2S8
    Hand Clin 24:425-44, vi-vii. 2008
    ..Cortical plasticity and its manipulation may one day become important contributors to improve functional outcome following nerve transfer...
  44. doi request reprint Electrophysiological features of myoclonus-dystonia
    Jie Yuan Li
    Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
    Mov Disord 23:2055-61. 2008
    ....
  45. pmc Representation of facial muscles in human motor cortex
    Guillermo O Paradiso
    The Krembil Neuroscience Centre and Toronto Western Research Institute, Ontario M5T 2S8, Canada
    J Physiol 567:323-36. 2005
    ..There is M1 projection to the contralateral upper and lower facial muscles in humans and the facial M1 area is susceptible to cortical inhibition and facilitation, similar to limb muscles...
  46. ncbi request reprint Reduced cerebellar inhibition in schizophrenia: a preliminary study
    Zafiris J Daskalakis
    Schizophrenia Program, Centre for Addiction and Mental Health, University of Toronto, Ont M5T 1R8, Canada
    Am J Psychiatry 162:1203-5. 2005
    ..The authors' goal was to use transcranial magnetic stimulation to measure cerebellar inhibition, a proxy of cerebellar activity, as the principal output of the cerebellum is inhibitory...
  47. ncbi request reprint Short and long latency afferent inhibition in Parkinson's disease
    Alexandra Sailer
    5W445 Toronto Western Hospital, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8
    Brain 126:1883-94. 2003
    ..LAI probably involves other pathways such as the basal ganglia or cortical association areas. This defective sensorimotor integration may be a non-dopaminergic manifestation of Parkinson's disease...
  48. ncbi request reprint Involvement of human thalamus in the preparation of self-paced movement
    Guillermo Paradiso
    The Krembil Neuroscience Centre and Toronto Western Research Institute, Toronto, Ontario, Canada
    Brain 127:2717-31. 2004
    ..Different cortico-subcortical circuits may mediate alpha and beta oscillations. During movement preparation, the motor thalamus and the supplementary motor area predominantly interact in the beta band...
  49. ncbi request reprint Cortical plasticity following upper extremity injury and reconstruction
    Dimitri J Anastakis
    Division of Plastic and Orthopaedic Surgery, University of Toronto, University Health Network, Toronto, Ontario M5T 2S8, Canada
    Clin Plast Surg 32:617-34, viii. 2005
    ..Therefore, cortical plasticity and its manipulation may be an important contributor to functional outcome following reconstruction. In the future, cortical plasticity may have implications for reconstruction and rehabilitation...
  50. ncbi request reprint Two phases of short-interval intracortical inhibition
    Lailoma Roshan
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, University of Toronto, 5W 445, 399 Bathurst Street, Toronto, Ontario, M5T 2S8, Canada
    Exp Brain Res 151:330-7. 2003
    ..SICI at 1 ms cannot be fully explained by axonal refractoriness and synaptic inhibition may be involved. SICI is a complex phenomenon and inhibition at different ISIs may be mediated by different inhibitory circuits...
  51. pmc The mechanisms of interhemispheric inhibition in the human motor cortex
    Zafiris J Daskalakis
    Centre for Addiction and Mental Health, Toronto, Ontario, Canada
    J Physiol 543:317-26. 2002
    ..In contrast, the mechanisms mediating short interval intracortical inhibition are probably different from those mediating long interval intracortical inhibition and interhemispheric inhibition although these systems appear to interact...
  52. ncbi request reprint Effect of low-frequency repetitive transcranial magnetic stimulation on interhemispheric inhibition
    Pramod Kr Pal
    Divsion of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
    J Neurophysiol 94:1668-75. 2005
    ..Treatment protocols using low-frequency rTMS to reduce cortical excitability in neurological and psychiatric conditions need to take into account their effects on IHI...
  53. pmc Mirror movements in parkinsonism: evaluation of a new clinical sign
    A J Espay
    Division of Neurology, Department of Medicine, Toronto Western Research Institute, University of Toronto, Toronto, Ontario M5T 258, Canada
    J Neurol Neurosurg Psychiatry 76:1355-8. 2005
    ..Mirror movements (MM) are not widely appreciated in parkinsonism and no report has evaluated this clinical sign in detail...
  54. ncbi request reprint Isolated diaphragmatic tremor: is there a spectrum in "respiratory myoclonus"?
    A J Espay
    Toronto Western Research Institute and Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
    Neurology 69:689-92. 2007
    ..The effects of distracting maneuvers on diaphragmatic activity have not been investigated...
  55. ncbi request reprint Relationship between P50 suppression and the cortical silent period
    Bertram Moller
    Schizophrenia Program, Centre for Addiction and Mental Health, Universty of Toronto, 250 College Street, M5T IR8, Toronto, Ontario, Canada
    Neuroreport 18:1503-6. 2007
    ....
  56. ncbi request reprint Dissociation of thalamic high frequency oscillations and slow component of sensory evoked potentials following damage to ascending pathways
    Ritsuko Hanajima
    Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, ONT Canada
    Clin Neurophysiol 117:906-11. 2006
    ..In this study, we examined how lesions in the sensory afferent pathway affect these components...
  57. ncbi request reprint Possible differences between the time courses of presynaptic and postsynaptic GABAB mediated inhibition in the human motor cortex
    Jason Chu
    Division of Neurology, Department of Medicine, Toronto Western Research Institute and Krembil Neuroscience Centre, University Health Network, University of Toronto, Toronto, ON, Canada
    Exp Brain Res 184:571-7. 2008
    ..0072). These findings suggest that the time courses of presynaptic and postsynaptic GABA(B) receptors mediated inhibition are different in the human motor cortex...
  58. doi request reprint Contralesional repetitive transcranial magnetic stimulation for chronic hemiparesis in subcortical paediatric stroke: a randomised trial
    Adam Kirton
    Division of Neurology, Department of Pediatrics, Alberta Children s Hospital, University of Calgary, Calgary, Canada
    Lancet Neurol 7:507-13. 2008
    ..We aimed to test whether contralesional, inhibitory repetitive transcranial magnetic stimulation (rTMS) could affect interhemispheric inhibition to improve hand function in chronic subcortical paediatric AIS...
  59. ncbi request reprint The cerebellothalamocortical pathway in essential tremor
    Andrew D Pinto
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, Ontario, Canada
    Neurology 60:1985-7. 2003
    ....
  60. doi request reprint Dysfunctional neural plasticity in patients with schizophrenia
    Zafiris J Daskalakis
    Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
    Arch Gen Psychiatry 65:378-85. 2008
    ..In schizophrenia, dysfunctional neural plasticity has been proposed as a key pathophysiological mechanism...
  61. doi request reprint Reduced intracortical and interhemispheric inhibitions in corticobasal syndrome
    Pramod Kr Pal
    Division of Neurology and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    J Clin Neurophysiol 25:304-12. 2008
    ..In conclusion, CBS patients had deficits in intracortical and interhemispheric inhibition in the representations for both distal and proximal upper limb muscles bilaterally with relative sparing of motor cortical output pathways...
  62. doi request reprint Two phases of interhemispheric inhibition between motor related cortical areas and the primary motor cortex in human
    Zhen Ni
    Division of Neurology, Krembil Neuroscience Centre and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    Cereb Cortex 19:1654-65. 2009
    ..We conclude that there are 2 distinct phases of IHI from motor related cortical areas to the opposite M1 through the corpus callosum, and they are mediated by different neuronal populations...
  63. ncbi request reprint TMS neuro-cardiovascular coupling in vascular compression cranial neuropathy
    Adam Kirton
    Division of Neurology, Alberta Children s Hospital, University of Calgary, Calgary, Alberta, Canada
    Can J Neurol Sci 36:83-8. 2009
    ..We hypothesized that the arterial pressure wave (APW) would interact at the neurovascular interface in NVC to inhibit transmission of transcranial magnetic stimulation (TMS) stimuli to affected muscles...
  64. ncbi request reprint The effects of repetitive transcranial magnetic stimulation on cortical inhibition in healthy human subjects
    Zafiris J Daskalakis
    Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
    Exp Brain Res 174:403-12. 2006
    ..Baseline physiological characteristics may be further explored as a method to select patients who may benefit from rTMS treatment...
  65. ncbi request reprint The relationship between cortical inhibition, antipsychotic treatment, and the symptoms of schizophrenia
    Shi Kai Liu
    Centre for Addiction and Mental Health, University of Toronto, Ontario, Canada
    Biol Psychiatry 65:503-9. 2009
    ..Such differential association patterns between clinical symptoms and CI deficits and their relationship to antipsychotic treatment thus might provide insights to the pathophysiology of schizophrenia...
  66. ncbi request reprint Measurement and modulation of plasticity of the motor system in humans using transcranial magnetic stimulation
    Robert Chen
    Division of Neurology, Dept of Medicine, University of Toronto, Ontario
    Motor Control 13:442-53. 2009
    ..Furthermore, TMS may be used to modulate brain plasticity and has therapeutic potential in neurological and psychiatric disorders such as stroke, Parkinson's disease, dystonia and depression...
  67. doi request reprint Suppression of gamma-oscillations in the dorsolateral prefrontal cortex following long interval cortical inhibition: a TMS-EEG study
    Faranak Farzan
    Department of Psychiatry, Center for Addiction and Mental Health, University of Toronto, Toronto, ON M5T1R8, Canada
    Neuropsychopharmacology 34:1543-51. 2009
    ..Such specificity suggests that the modulation of gamma-oscillations may represent an important neurophysiological process that may, in part, be responsible for optimal DLPFC functioning in healthy human subjects...
  68. pmc Repetitive transcranial magnetic stimulation: faster or longer is not necessarily more
    Zhen Ni
    Division of Neurology, Krembil Neuroscience Centre and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    J Physiol 586:3733-4. 2008
  69. doi request reprint Evidence for gamma inhibition deficits in the dorsolateral prefrontal cortex of patients with schizophrenia
    Faranak Farzan
    Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, M5T 1R8, Canada
    Brain 133:1505-14. 2010
    ....
  70. pmc Effect of long interval interhemispheric inhibition on intracortical inhibitory and facilitatory circuits
    Kaviraja Udupa
    Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
    J Physiol 588:2633-41. 2010
    ..We conclude that different sets of cortical neurons mediate LIHI, SICI, ICF and LICI. GABA(B)-mediated LICI and LIHI have inhibitory interactions with each other while LIHI has an additive effect with GABA(A)-mediated SICI...
  71. ncbi request reprint Evidence for impaired cortical inhibition in schizophrenia using transcranial magnetic stimulation
    Zafiris J Daskalakis
    Schizophrenia and Continuing Care Program, Centre for Addiction and Mental Health, Department of Psychiatry, Toronto Western General Hospital, University of Toronto, Ontario, Canada
    Arch Gen Psychiatry 59:347-54. 2002
    ....
  72. ncbi request reprint Transcranial magnetic stimulation: a new investigational and treatment tool in psychiatry
    Zafiris J Daskalakis
    Schizophrenia and Continuing Care Program, Centre for Addiction and Mental Health, 7th Floor Clarke Division, University of Toronto, 250 College Street, Toronto, Ontario, Canada
    J Neuropsychiatry Clin Neurosci 14:406-15. 2002
    ..The most serious side effect of high-frequency rTMS is seizures. TMS represents an exciting new frontier in neuroscience research, providing insights into the pathophysiology and treatment of various neuropsychiatric disorders...
  73. ncbi request reprint An automated method to determine the transcranial magnetic stimulation-induced contralateral silent period
    Zafiris J Daskalakis
    Centre for Addiction and Mental Health, Schizophrenia and Continuing Care Program, University of Toronto, Ontario, Canada
    Clin Neurophysiol 114:938-44. 2003
    ..The determination of the return of voluntary motor activity is typically accomplished via visual inspection of the electromyography (EMG) waveform and may be subject to inaccuracy on the part of the rater...
  74. ncbi request reprint Somatosensory evoked potentials (SEPs) recorded from deep brain stimulation (DBS) electrodes in the thalamus and subthalamic nucleus (STN)
    Ritsuko Hanajima
    Toronto Western Research Institute, Toronto Western Hospital, 399 Bathurst St, Toronto, ON M5T 2S8, Canada
    Clin Neurophysiol 115:424-34. 2004
    ..To examine the location of deep brain stimulation (DBS) electrode somatosensory evoked potentials (SEPs) and determine the generators of the median nerve SEPs recorded in thalamus and subthalamic nucleus (STN)...
  75. pmc Effects of short interval intracortical inhibition and intracortical facilitation on short interval intracortical facilitation in human primary motor cortex
    Aparna Wagle-Shukla
    Toronto Western Hospital, 399 Bathurst Street, Toronto, Ontario M5T 2S8, Canada
    J Physiol 587:5665-78. 2009
    ..ICF decreased the third peak of SICF. We conclude that SICI facilitates SICF at neuronal circuits responsible for generating late I waves through disinhibition, while ICF may have the opposite effects...
  76. ncbi request reprint Cortical and spinal abnormalities in psychogenic dystonia
    Alberto J Espay
    Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
    Ann Neurol 59:825-34. 2006
    ..We tested the hypothesis that aberrant sensory input associated with abnormal posture may cause similar abnormalities by testing patients with psychogenic dystonia...
  77. ncbi request reprint Effect of antipsychotics on cortical inhibition using transcranial magnetic stimulation
    Zafiris J Daskalakis
    Schizophrenia Program, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
    Psychopharmacology (Berl) 170:255-62. 2003
    ..Therefore, single administration of an antipsychotic has no effect on CI or resting motor threshold. Whether chronic, repeated administration of antipsychotics has effects on CI requires further investigation...
  78. doi request reprint Digit somatotopy within cortical areas of the postcentral gyrus in humans
    Aimee J Nelson
    Division of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
    Cereb Cortex 18:2341-51. 2008
    ..This study additionally identified the specific digit pairs that are separable in areas 3b and 1 using current imaging methods. Somatotopy was not resolved in area 2 or in the inferior area 1 foci...
  79. doi request reprint Cerebral blood flow changes induced by pedunculopontine nucleus stimulation in patients with advanced Parkinson's disease: a [(15)O] H2O PET study
    Benedicte Ballanger
    Toronto Western Research Institute Division of Brain, Imaging and Behaviour Systems Neuroscience, UHN, University of Toronto, Toronto, Ontario, Canada
    Hum Brain Mapp 30:3901-9. 2009
    ..Whether these findings are associated with the DBS-PPN clinical effect remains to be proven. However, they suggest that PPN modulation may induce functional changes in neural networks associated with the control of lower limb movements...
  80. ncbi request reprint Identification of arm movements using correlation of electrocorticographic spectral components and kinematic recordings
    César Márquez Chin
    Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
    J Neural Eng 4:146-58. 2007
    ..To confirm these findings, a nearest neighbour classifier was applied to identify the specific movement that each participant had performed. The achieved classification accuracy was 89%...
  81. ncbi request reprint Orthostatic tremor in progressive supranuclear palsy
    Rob M A De Bie
    Movement Disorders Center, Division of Neurology, Toronto Western Hospital, Toronto, Ontario, Canada
    Mov Disord 22:1192-4. 2007
    ..quot; We describe a patient with OT, with postural tremor of the arms and restless legs syndrome (RLS), who developed features typical of progressive supranuclear palsy (PSP). PSP can be accompanied by OT...
  82. pmc Direct demonstration of inhibitory interactions between long interval intracortical inhibition and short interval intracortical inhibition
    Zhen Ni
    7MC 411, Toronto Western Hospital, 399 Bathurst Street, Toronto, Ontario, M5T 2S8, Canada
    J Physiol 589:2955-62. 2011
    ..We conclude that decreased SICI in the presence of LICI is not due to changes in I-wave content induced by LICI and is caused by their interactions at the cortical level...
  83. doi request reprint Transcranial magnetic stimulation in different current directions activates separate cortical circuits
    Zhen Ni
    Division of Neurology, Krembil Neuroscience Centre and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    J Neurophysiol 105:749-56. 2011
    ..SAI produced more inhibition of late I-waves generated by PA than those generated by AP current direction. We conclude that late I-waves generated by PA and AP current directions are mediated by different neuronal mechanisms...
  84. ncbi request reprint Involvement of the basal ganglia and cerebellar motor pathways in the preparation of self-initiated and externally triggered movements in humans
    Jamie Purzner
    The Krembil Neuroscience Centre and Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
    J Neurosci 27:6029-36. 2007
    ..The CTC pathway is involved in the preparation of self-paced but not externally cued movements, although the pathway may still be involved in the execution of these movements...
  85. ncbi request reprint Saccade-related potentials recorded from human subthalamic nucleus
    Adrian P Fawcett
    Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ont, Canada
    Clin Neurophysiol 118:155-63. 2007
    ..To investigate an ocular motor role for the STN in Parkinson's disease (PD) patients...
  86. doi request reprint Digit-specific aberrations in the primary somatosensory cortex in Writer's cramp
    Aimee J Nelson
    Toronto Western Research Institute, University of Toronto, Toronto, Canada
    Ann Neurol 66:146-54. 2009
    ..Our aim was to characterize the spatial relationships among individual digits to determine the types of aberrations that exist and whether these are specific to symptomatic digits only...
  87. doi request reprint Changing the "when" and "what" of intended actions
    Sukhvinder S Obhi
    Centre for Cognitive Neuroscience and Wilfrid Laurier University, Waterloo, Ontario, Canada
    J Neurophysiol 102:2755-62. 2009
    ..Interactions between these two mechanisms could account for our behavioral results...
  88. doi request reprint Potentiation of gamma oscillatory activity through repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex
    Mera S Barr
    Schizophrenia Program, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
    Neuropsychopharmacology 34:2359-67. 2009
    ....
  89. ncbi request reprint Changes in cortical and pallidal oscillatory activity during the execution of a sensory trick in patients with cervical dystonia
    Joyce K H Tang
    Department of Physiology, Med Sci Bldg 3302, 1 King s College Circle, University of Toronto, Toronto, Ontario, Canada M5S 1A8
    Exp Neurol 204:845-8. 2007
    ..These preliminary findings suggest a role for 4-8 Hz frequency synchronization in the pathophysiology of dystonia...
  90. ncbi request reprint Multimodal imaging of brain reorganization in motor areas of the contralesional hemisphere of well recovered patients after capsular stroke
    Christian Gerloff
    Cortical Physiology Research Group, Department of Neurology, Eberhard Karls University Medical School, Tuebingen, Germany
    Brain 129:791-808. 2006
    ....
  91. pmc Task-dependent intracortical inhibition is impaired in focal hand dystonia
    Cathrin M Butefisch
    Human Motor Control Section, National Institute of Neurological Disease and Stroke, National Institutes of Health, Bethesda, Maryland 20892 1428, USA
    Mov Disord 20:545-51. 2005
    ..We found that performance of the selective but not the nonselective task resulted in increased SICI in the 4DIO of normal but not in dystonic subjects. We conclude that task-dependent SICI is disturbed in patients with dystonia...
  92. ncbi request reprint Constraint-induced therapy in stroke: magnetic-stimulation motor maps and cerebral activation
    George F Wittenberg
    Human Cortical Physiology Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
    Neurorehabil Neural Repair 17:48-57. 2003
    ..Both changes may reflect improved ability of upper motor neurons to produce movement...
  93. ncbi request reprint Single pulse stimulation of the human subthalamic nucleus facilitates the motor cortex at short intervals
    Ritsuko Hanajima
    Dept of Neurology, University of Tokyo Hospital, 7 3 1 Hongo, Bunkyo ku, Tokyo 113 8655, Japan
    J Neurophysiol 92:1937-43. 2004
    ..Single pulse STN stimulation facilitates the M1 at short latencies. The possible mechanisms include antidromic excitation of the cortico-STN fibers or transmission through the basal ganglia-thalamocortical pathway...
  94. ncbi request reprint Interhemispheric inhibition in distal and proximal arm representations in the primary motor cortex
    Michelle L Harris-Love
    Human Cortical Physiology Section, National Institute of Neurological Disorders and Stroke, 10 Center Drive, MSC 1428, Bldg 10, Rm 5N226, Bethesda, MD 20892, USA
    J Neurophysiol 97:2511-5. 2007
    ..This finding suggests the amount of IHI between different arm representations does not strictly follow a proximal-to-distal gradient, but may be related to the role of each muscle in functional movement synergies...
  95. ncbi request reprint Interhemispheric and ipsilateral connections in Parkinson's disease: relation to mirror movements
    Jie Yuan Li
    Division of Neurology, Department of Medicine, Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada
    Mov Disord 22:813-21. 2007
    ..These deficits in transcallosal inhibition may contribute to MM in PD patients...
  96. ncbi request reprint Effects of apomorphine on flexor reflex and periodic limb movement
    Guillermo Paradiso
    Division of Neurology, Toronto Western Hospital and The Toronto Western Research Institute, University Health Network, University of Toronto, Toronoto, Ontario, Canada
    Mov Disord 17:594-7. 2002
    ..These findings demonstrate that dopaminergic agents can suppress exaggerated FR in humans, and support the hypothesis of common mechanisms for PLM and FR...
  97. ncbi request reprint Rapid modulation of GABA in sensorimotor cortex induced by acute deafferentation
    Lucien M Levy
    Neuroimaging Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 10, 5D20, Bethesda, MD 20892, USA
    Ann Neurol 52:755-61. 2002
    ..Reduction of brain GABA can play a pivotal role in regulating the extent of rapid cortical reorganization after lesions or changes in sensory input...
  98. ncbi request reprint Fixed dystonia unresponsive to pallidal stimulation improved by motor cortex stimulation
    Alberto J Espay
    Neurology 69:1062-3; author reply 1063. 2007
  99. ncbi request reprint Intensity-dependent effects of 1 Hz rTMS on human corticospinal excitability
    Paul B Fitzgerald
    Department of Psychological Medicine, Dandenong Psychiatry Research Centre, Monash University, P O Box 956, Victoria 3175, Australia
    Clin Neurophysiol 113:1136-41. 2002
    ..This study explored whether the effects of repetitive transcranial magnetic stimulation (rTMS) on corticospinal excitability are dependent on the stimulation intensity and examined the effect of rTMS on inhibitory function...
  100. ncbi request reprint Subthalamic nucleus and gait disturbance: interactions between basal ganglia and brainstem and spinal pathways?
    Robert Chen
    Neurology 63:1150-1. 2004