scholarly journals Role of the Cerebellum in Externally Paced Rhythmic Finger Movements

2007 ◽  
Vol 98 (1) ◽  
pp. 145-152 ◽  
Author(s):  
Miguel Fernandez Del Olmo ◽  
Binith Cheeran ◽  
Giacomo Koch ◽  
John C. Rothwell
Keyword(s):  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Random Order ◽  
Cerebellar Hemisphere ◽  
Continuation Phase ◽  
Visual Cue ◽  
Synchronization Phase ◽  
Left Cerebellar Hemisphere ◽  
The Right

Several studies have suggested that the cerebellum has an important role in timing of subsecond intervals. Previous studies using transcranial magnetic stimulation (TMS) to test this hypothesis directly have produced inconsistent results. Here we used 1-Hz repetitive TMS (rTMS) for 10 min over the right or left cerebellar hemisphere to interfere transiently with cerebellar processing to assess its effect on the performance of a finger-tapping task. Subjects tapped with their right index finger for 1 min (synchronization phase) with an auditory or visual cue at 0.5, 1, or 2 Hz; they continued for a further 1 min at the same rate with no cues (continuation phase). The blocks of trials were performed in a random order. rTMS of the cerebellum ipsilateral to the movement increased the variability of the intertap interval but only for movements at 2 Hz that were made while subjects were synchronizing with an auditory cue. There was no effect on the continuation phase of the task when the cues were no longer present or on synchronization with a visual cue. Similar results were seen after stimulation over the contralateral dorsal premotor cortex but not after rTMS over supplementary motor area. There was no effect after rTMS over the ipsilateral right cervical nerve roots or over the ipsilateral primary motor cortex. The results support the hypothesis of neural network for event-related timing in the subsecond range that involves a cerebellar-premotor network.

scholarly journals Reduced Interhemispheric Coherence in Cerebellar Kainic Acid-Induced Lateralized Dystonia

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.

Connectivity-Related Roles of Contralesional Brain Regions for Motor Performance Early after Stroke

2020 ◽  
Author(s):  
Lukas Hensel ◽  
Caroline Tscherpel ◽  
Jana Freytag ◽  
Stella Ritter ◽  
Anne K Rehme ◽  
...  
Keyword(s):  
Neural Activity ◽  
Motor Performance ◽  
Primary Motor Cortex ◽  
Effective Connectivity ◽  
Premotor Cortex ◽  
Brain Regions ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Anterior Intraparietal Sulcus

Abstract Hemiparesis after stroke is associated with increased neural activity not only in the lesioned but also in the contralesional hemisphere. While most studies have focused on the role of contralesional primary motor cortex (M1) activity for motor performance, data on other areas within the unaffected hemisphere are scarce, especially early after stroke. We here combined functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) to elucidate the contribution of contralesional M1, dorsal premotor cortex (dPMC), and anterior intraparietal sulcus (aIPS) for the stroke-affected hand within the first 10 days after stroke. We used “online” TMS to interfere with neural activity at subject-specific fMRI coordinates while recording 3D movement kinematics. Interfering with aIPS activity improved tapping performance in patients, but not healthy controls, suggesting a maladaptive role of this region early poststroke. Analyzing effective connectivity parameters using a Lasso prediction model revealed that behavioral TMS effects were predicted by the coupling of the stimulated aIPS with dPMC and ipsilesional M1. In conclusion, we found a strong link between patterns of frontoparietal connectivity and TMS effects, indicating a detrimental influence of the contralesional aIPS on motor performance early after stroke.

Rare Abnormality of the Posterior Fossa: Unilateral İsolated Cerebellar Hypoplasia

2020 ◽  
Author(s):  
Merter Keçeli
Keyword(s):  
Posterior Fossa ◽  
Male Patient ◽  
Cerebellar Vermis ◽  
Cerebellar Hemisphere ◽  
Cerebellar Hypoplasia ◽  
Developmental Abnormalities ◽  
Neuromuscular Abnormalities ◽  
Left Cerebellar Hemisphere ◽  
The Right ◽  
Neuromotor Development

AbstractThe cerebellum abnormalities may be hypoplastic, dysplastic, or hypoplastic. It is very rare that the cerebellar hemisphere is affected unilaterally in the posterior fossa abnormalities. The reason for this effect is mostly sequela. This pathology presents with neuromotor developmental abnormalities. In this presentation, isolated left cerebellar hypoplasia is described radiologically in a 21-month-old male patient with neuromotor development defects. Dysplastic appearance was noticeable in the observable part of the left cerebellar hemisphere and folia. The cerebellar vermis could not be shaped. The right cerebellar hemisphere, other posterior fossa formations, and supratentorial area were natural. In patients with neuromuscular abnormalities, the posterior fossa is applied with care. It should be remembered that cerebellar hypoplasia and dysplasia can be unilateral.

The role of the right premotor cortex and temporo-parietal junction in defensive responses to visual threats

Cortex ◽  
2019 ◽  
Vol 120 ◽  
pp. 532-538
Author(s):  
Laura Sagliano ◽  
Maria Vela ◽  
Luigi Trojano ◽  
Massimiliano Conson
Keyword(s):  
Premotor Cortex ◽  
Defensive Responses ◽  
The Right

scholarly journals Writing's Shadow: Corticospinal Activation during Letter Observation

2012 ◽  
Vol 24 (5) ◽  
pp. 1138-1148 ◽  
Author(s):  
Masahiro Nakatsuka ◽  
Mohamed Nasreldin Thabit ◽  
Satoko Koganemaru ◽  
Ippei Nojima ◽  
Hidenao Fukuyama ◽  
...  
Keyword(s):  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Short Interval ◽  
Single Pulse ◽  
Random Order ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Motor Memory ◽  
F Wave ◽  
The Right

We can recognize handwritten letters despite the variability among writers. One possible strategy is exploiting the motor memory of orthography. By using TMS, we clarified the excitatory and inhibitory neural circuits of the motor corticospinal pathway that might be activated during the observation of handwritten letters. During experiments, participants looked at the handwritten or printed single letter that appeared in a random order. The excitability of the left and right primary motor cortex (M1) was evaluated by motor-evoked potentials elicited by single-pulse TMS. Short interval intracortical inhibition (SICI) of the left M1 was evaluated using paired-pulse TMS. F waves were measured for the right ulnar nerve. We found significant reduction of corticospinal excitability only for the right hand at 300–400 msec after each letter presentation without significant changes in SICI. This suppression is likely to be of supraspinal origin, because of no significant alteration in F-wave amplitudes. These findings suggest that the recognition of handwritten letters may include the implicit knowledge of “writing” in M1. The M1 activation associated with that process, which has been shown in previous neuroimaging studies, is likely to reflect the active suppression of the corticospinal excitability.

Neural Network Configuration and Efficiency Underlies Individual Differences in Spatial Orientation Ability

2014 ◽  
Vol 26 (2) ◽  
pp. 380-394 ◽  
Author(s):  
Aiden E. G. F. Arnold ◽  
Andrea B. Protzner ◽  
Signe Bray ◽  
Richard M. Levy ◽  
Giuseppe Iaria
Keyword(s):  
Individual Differences ◽  
Spatial Orientation ◽  
Primary Motor Cortex ◽  
Brain Regions ◽  
Network Configuration ◽  
Supramarginal Gyrus ◽  
Neural Basis ◽  
Left Hippocampus ◽  
The Right

Spatial orientation is a complex cognitive process requiring the integration of information processed in a distributed system of brain regions. Current models on the neural basis of spatial orientation are based primarily on the functional role of single brain regions, with limited understanding of how interaction among these brain regions relates to behavior. In this study, we investigated two sources of variability in the neural networks that support spatial orientation—network configuration and efficiency—and assessed whether variability in these topological properties relates to individual differences in orientation accuracy. Participants with higher accuracy were shown to express greater activity in the right supramarginal gyrus, the right precentral cortex, and the left hippocampus, over and above a core network engaged by the whole group. Additionally, high-performing individuals had increased levels of global efficiency within a resting-state network composed of brain regions engaged during orientation and increased levels of node centrality in the right supramarginal gyrus, the right primary motor cortex, and the left hippocampus. These results indicate that individual differences in the configuration of task-related networks and their efficiency measured at rest relate to the ability to spatially orient. Our findings advance systems neuroscience models of orientation and navigation by providing insight into the role of functional integration in shaping orientation behavior.

Successful therapy for temporomandibular pain alters anterior insula and cerebellar representations of occlusion

Cephalalgia ◽  
2013 ◽  
Vol 33 (15) ◽  
pp. 1248-1257 ◽  
Author(s):  
Rita Lickteig ◽  
Martin Lotze ◽  
Bernd Kordass
Keyword(s):  
Pain Syndrome ◽  
Anterior Insula ◽  
Cerebellar Hemisphere ◽  
Before And After ◽  
Pain Ratings ◽  
Subjective Pain ◽  
Left Cerebellar Hemisphere ◽  
Posterior Insula ◽  
The Right ◽  
The Impact

Aim Craniomandibular disorders (CMD) are widespread, but we know little about the cerebral representations associated with this pain syndrome and nothing about changes in cerebral representations of occlusion induced by common therapy approaches. Methods In a longitudinal therapy study, we applied functional magnetic resonance imaging (fMRI) in 14 patients with mild CMD during occlusal movements. fMRI, pain scoring, kinematic investigations of occlusal movements, and jaw muscle electromyography (EMG) were measured before and after two weeks of therapy with an individually optimized Michigan splint. Results The patients’ subjective pain ratings decreased, and the symmetry of condylar movements increased over the period of therapy. After therapy, EMG of the jaw muscles demonstrated more relaxed resting conditions and increased activity during maximal occlusion. fMRI during occlusion showed an activation decrease in the right anterior insula and right cerebellum over the course of therapy. Correlation analysis between pain score and fMRI activation decreases identified right anterior insula, left posterior insula and left cerebellar hemisphere. Left cerebellar and right primary motor activation magnitude was negatively associated with symmetry of the condylar movements. Conclusions Our findings highlight the impact of the anterior insula for the internal monitoring and the anticipation of temporomandibular joint (TMJ) pain. In addition, an increase of symmetry of condylar movements after therapy has been associated with a decrease of activation magnitude in primary motor and cerebellar regions.

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