Slowing fastest finger movements of the dominant hand with low-frequency rTMS of the hand area of the primary motor cortex

The role of primary motor cortex (M1) in the control of voluntary movements is still unclear. In brain functional imaging studies of unilateral hand performance, bilateral M1 activation is inconsistently observed, and disruptions of M1 using repetitive transcranial magnetic stimulation (rTMS) lead to variable results in the hand motor performance. As the motor tasks differed qualitatively in these studies, it is conceivable that M1 contribution differs depending on the level of skillfulness. The objective of the present study was to determine whether M1 contribution to hand motor performance differed depending on the level of precision of the motor task. Here, we used low-frequency rTMS of left M1 to determine its effect on the performance of a pointing task that allows the parametric increase of the level of precision and thereby increase the level of required precision quantitatively. We found that low-frequency rTMS improved performance in both hands for the task with the highest demand on precision, whereas performance remained unchanged for the tasks with lower demands. These results suggest that the functional relevance of M1 activity for motor performance changes as a function of motor demand. The bilateral effect of rTMS to left M1 would also support the notion of M1 functions at a higher level in motor control by integrating afferent input from nonprimary motor areas.

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Low-frequency rTMS inhibitory effects in the primary motor cortex: Insights from TMS-evoked potentials

NeuroImage ◽

10.1016/j.neuroimage.2014.04.065 ◽

2014 ◽

Vol 98 ◽

pp. 225-232 ◽

Cited By ~ 48

Author(s):

Elias P. Casula ◽

Vincenza Tarantino ◽

Demis Basso ◽

Giorgio Arcara ◽

Giuliana Marino ◽

...

Keyword(s):

Motor Cortex ◽

Evoked Potentials ◽

Primary Motor Cortex ◽

Low Frequency ◽

Inhibitory Effects ◽

Low Frequency Rtms

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Limited Functional Grouping of Neurons in the Motor Cortex Hand Area During Individuated Finger Movements: A Cluster Analysis

Journal of Neurophysiology ◽

10.1152/jn.1999.82.6.3488 ◽

1999 ◽

Vol 82 (6) ◽

pp. 3488-3505 ◽

Cited By ~ 59

Author(s):

Andrew V. Poliakov ◽

Marc H. Schieber

Keyword(s):

Cluster Analysis ◽

Motor Cortex ◽

Small Group ◽

Functional Groups ◽

Small Groups ◽

Primary Motor Cortex ◽

Finger Movements ◽

Neuronal Populations ◽

Hand Area ◽

Functional Grouping

Primary motor cortex (M1) hand area neurons show patterns of discharge across a set of individuated finger and wrist movements so diverse as to preclude classifying the neurons into functional groups on the basis of simple inspection. We therefore applied methods of cluster analysis to search M1 neuronal populations for groups of neurons with similar patterns of discharge across the set of movements. Populations from each of three monkeys showed a large group of neurons the discharge of which increased for many or all of the movements and a second small group the discharge of which decreased for many or all movements. Two to three other small groups of neurons that discharged more specifically for one or two movements also were found in each monkey, but these groups were less consistent than the groups with broad movement fields. The limited functional grouping of M1 hand area neurons suggests that M1 neurons act as a network of highly diverse elements in controlling individuated finger movements.

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Partial Inactivation of the Primary Motor Cortex Hand Area: Effects on Individuated Finger Movements

Journal of Neuroscience ◽

10.1523/jneurosci.18-21-09038.1998 ◽

1998 ◽

Vol 18 (21) ◽

pp. 9038-9054 ◽

Cited By ~ 89

Author(s):

Marc H. Schieber ◽

Andrew V. Poliakov

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Finger Movements ◽

Area Effects ◽

Partial Inactivation ◽

Hand Area

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Bilateral low frequency rTMS of the primary motor cortex may not be a suitable treatment for levodopa-induced dyskinesias in late stage Parkinson's disease

Parkinsonism & Related Disorders ◽

10.1016/j.parkreldis.2015.11.009 ◽

2016 ◽

Vol 22 ◽

pp. 62-67 ◽

Cited By ~ 15

Author(s):

Anja Flamez ◽

Ann Cordenier ◽

Sylvie De Raedt ◽

Véronique Michiels ◽

Sara Smetcoren ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Motor Cortex ◽

Late Stage ◽

Primary Motor Cortex ◽

Low Frequency ◽

Suitable Treatment ◽

Low Frequency Rtms

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Preconditioning with low frequency rTMS over right motor cortex (M1) influences the effect of intermittent Theta Burst Stimulation on excitability over left M1

Klinische Neurophysiologie ◽

10.1055/s-2008-1072843 ◽

2008 ◽

Vol 39 (01) ◽

Author(s):

P Ragert ◽

M Camus ◽

Y Vandermeeren ◽

LG Cohen

Keyword(s):

Motor Cortex ◽

Low Frequency ◽

Theta Burst Stimulation ◽

Burst Stimulation ◽

Theta Burst ◽

Low Frequency Rtms

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Reduced Interhemispheric Coherence in Cerebellar Kainic Acid-Induced Lateralized Dystonia

Frontiers in Neurology ◽

10.3389/fneur.2020.580540 ◽

2020 ◽

Vol 11 ◽

Author(s):

Elena Laura Georgescu Margarint ◽

Ioana Antoaneta Georgescu ◽

Carmen Denise Mihaela Zahiu ◽

Stefan-Alexandru Tirlea ◽

Alexandru Rǎzvan Şteopoaie ◽

...

Keyword(s):

Motor Cortex ◽

Kainic Acid ◽

Primary Motor Cortex ◽

Low Frequency ◽

Muscular Activity ◽

Cerebellar Hemisphere ◽

Interhemispheric Coherence ◽

General Locomotor Activity ◽

Complex Circuits ◽

The Right

The execution of voluntary muscular activity is controlled by the primary motor cortex, together with the cerebellum and basal ganglia. The synchronization of neural activity in the intracortical network is crucial for the regulation of movements. In certain motor diseases, such as dystonia, this synchrony can be altered in any node of the cerebello-cortical network. Questions remain about how the cerebellum influences the motor cortex and interhemispheric communication. This research aims to study the interhemispheric cortical communication between the motor cortices during dystonia, a neurological movement syndrome consisting of sustained or repetitive involuntary muscle contractions. We pharmacologically induced lateralized dystonia to adult male albino mice by administering low doses of kainic acid on the left cerebellar hemisphere. Using electrocorticography and electromyography, we investigated the power spectral densities, cortico-muscular, and interhemispheric coherence between the right and left motor cortices, before and during dystonia, for five consecutive days. Mice displayed lateralized abnormal motor signs, a reduced general locomotor activity, and a high score of dystonia. The results showed a progressive interhemispheric coherence decrease in low-frequency bands (delta, theta, beta) during the first 3 days. The cortico-muscular coherence of the affected side had a significant increase in gamma bands on days 3 and 4. In conclusion, lateralized cerebellar dysfunction during dystonia was associated with a loss of connectivity in the motor cortices, suggesting a possible cortical compensation to the initial disturbances induced by cerebellar left hemisphere kainate activation by blocking the propagation of abnormal oscillations to the healthy hemisphere. However, the cerebellum is part of several overly complex circuits, therefore other mechanisms can still be involved in this phenomenon.

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