The role of the inferior parietal lobule in writer’s cramp
Journal
Brain
ISSN
0006-8950
1460-2156
Date Issued
2020
Author(s)
Shabbir Hussain I Merchant
Eleni Frangos
Jacob Parker
Megan Bradson
Tianxia Wu
Giorgio Leodori
M C Bushnell
Silvina G Horovitz
Mark Hallett
Traian Popa
Type
Resource Types::text::journal::journal article
URL Institutional Repository
Abstract
<jats:title>Abstract</jats:title>
<jats:p>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.</jats:p>
<jats:p>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.</jats:p>
Subjects
cortical silent period
;
fine motor control
;
parietal lobe
;
task-specific dystonia
;
writer's cramp
;
adult
;
brain
;
brain mapping
;
dystonic disorders
;
evoked potentials, motor
;
female
;
humans
;
male
;
middle aged
;
motor cortex
;
neuronal plasticity
;
parietal lobe
;
psychomotor performance
;
transcranial magnetic stimulation
;
action potential amplitude
;
adult
;
aged
;
article
;
clinical article
;
clinical assessment
;
controlled study
;
cortical excitability
;
diffusion weighted imaging
;
female
;
finger tapping test
;
functional connectivity
;
functional magnetic resonance imaging
;
functional neuroimaging
;
human
;
inferior parietal lobule
;
long term depression
;
male
;
middle aged
;
motor control
;
motor cortex
;
motor evoked potential
;
multimodal imaging
;
neuronavigation
;
premotor cortex
;
priority journal
;
randomized controlled trial
;
tractography
;
transcranial magnetic stimulation
;
writer's cramp
;
brain
;
brain mapping
;
diagnostic imaging
;
dystonic disorder
;
metabolism
;
nerve cell plasticity
;
parietal lobe
;
pathophysiology
;
physiology
;
procedures
;
psychomotor performance