VIAL UNDURRAGA, FELIPE AGUSTIN
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VIAL UNDURRAGA, FELIPE AGUSTIN
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f.vial@udd.cl
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57217186119

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2022 2022 2021 2021 2020 2020 2019 2019 0.0 0.0 1.0 1.0 2.0 2.0 3.0 3.0 4.0 4.0 5.0 5.0

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Identifying transcranial magnetic stimulation induced EEG signatures of different neuronal elements in primary motor cortex

2022 , Zhen Ni , Sinisa Pajevic , Li Chen , Giorgio Leodori , VIAL UNDURRAGA, FELIPE AGUSTIN , Alexandru V. Avram , Yong Zhang , Patrick McGurrin , Leonardo G. Cohen , Peter J. Basser , Mark Hallett

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Re‐emergent Tremor in Parkinson's Disease: The Role of the Motor Cortex

2020 , Giorgio Leodori , Daniele Belvisi , Maria I. De Bartolo , Andrea Fabbrini , Matteo Costanzo , VIAL UNDURRAGA, FELIPE AGUSTIN , Antonella Conte , Mark Hallett , Alfredo Berardelli

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Myoclonus: An Electrophysiological Diagnosis

2020 , Shabbir Hussain I. Merchant , VIAL UNDURRAGA, FELIPE AGUSTIN , Giorgio Leodori , Jay A. Gerpen , Mark Hallett

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A novel exaggerated “spino-bulbo-spinal like” reflex of lower brainstem origin

2019 , Shabbir Hussain Merchant , VIAL UNDURRAGA, FELIPE AGUSTIN , Giorgio Leodori , Stanley Fahn , Seth L. Pullman , Mark Hallett

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Measuring latency distribution of transcallosal fibers using transcranial magnetic stimulation

2020 , Zhen Ni , Giorgio Leodori , VIAL UNDURRAGA, FELIPE AGUSTIN , Yong Zhang , Alexandru V. Avram , Sinisa Pajevic , Peter J. Basser , Mark Hallett

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Measuring conduction velocity distributions in peripheral nerves using neurophysiological techniques

2020 , Zhen Ni , VIAL UNDURRAGA, FELIPE AGUSTIN , Alexandru V. Avram , Giorgio Leodori , Sinisa Pajevic , Peter J. Basser , Mark Hallett

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The role of the inferior parietal lobule in writer’s cramp

2020 , Shabbir Hussain I Merchant , Eleni Frangos , Jacob Parker , Megan Bradson , Tianxia Wu , Felipe Vial-Undurraga , Giorgio Leodori , M C Bushnell , Silvina G Horovitz , Mark Hallett , Traian Popa

Abstract Humans have a distinguishing ability for fine motor control that is subserved by a highly evolved cortico-motor neuronal network. The acquisition of a particular motor skill involves a long series of practice movements, trial and error, adjustment and refinement. At the cortical level, this acquisition begins in the parieto-temporal sensory regions and is subsequently consolidated and stratified in the premotor-motor cortex. Task-specific dystonia can be viewed as a corruption or loss of motor control confined to a single motor skill. Using a multimodal experimental approach combining neuroimaging and non-invasive brain stimulation, we explored interactions between the principal nodes of the fine motor control network in patients with writer’s cramp and healthy matched controls. Patients and healthy volunteers underwent clinical assessment, diffusion-weighted MRI for tractography, and functional MRI during a finger tapping task. Activation maps from the task-functional MRI scans were used for target selection and neuro-navigation of the transcranial magnetic stimulation. Single- and double-pulse TMS evaluation included measurement of the input-output recruitment curve, cortical silent period, and amplitude of the motor evoked potentials conditioned by cortico-cortical interactions between premotor ventral (PMv)-motor cortex (M1), anterior inferior parietal lobule (aIPL)-M1, and dorsal inferior parietal lobule (dIPL)-M1 before and after inducing a long term depression-like plastic change to dIPL node with continuous theta-burst transcranial magnetic stimulation in a randomized, sham-controlled design. Baseline dIPL-M1 and aIPL-M1 cortico-cortical interactions were facilitatory and inhibitory, respectively, in healthy volunteers, whereas the interactions were converse and significantly different in writer’s cramp. Baseline PMv-M1 interactions were inhibitory and similar between the groups. The dIPL-PMv resting state functional connectivity was increased in patients compared to controls, but no differences in structural connectivity between the nodes were observed. Cortical silent period was significantly prolonged in writer’s cramp. Making a long term depression-like plastic change to dIPL node transformed the aIPL-M1 interaction to inhibitory (similar to healthy volunteers) and cancelled the PMv-M1 inhibition only in the writer’s cramp group. These findings suggest that the parietal multimodal sensory association region could have an aberrant downstream influence on the fine motor control network in writer’s cramp, which could be artificially restored to its normal function.

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