Two phases of interhemispheric inhibition between motor related cortical areas and the primary motor cortex in human

While neuroplasticity changes measured by transcranial magnetic stimulation have been proved to be highly correlated to motor recovery and have been tested in various forms of interventions, it has not been applied to investigate the neurophysiologic mechanism of acupuncture therapy. The aim of this study is to investigate neuroplasticity changes induced by a single session of acupuncture therapy in healthy adults, regarding the excitability change on bilateral primary motor cortex and interhemispheric inhibition. Ten subjects took a 30-minute acupuncture therapy and the same length relaxing phase in separate days. Transcranial magnetic stimulation measures, including resting motor threshold, amplitudes of motor-evoked potential, and interhemispheric inhibition, were assessed before and 10 minutes after intervention. Acupuncture treatment showed significant changes on potential amplitude from both ipsilateral and contralateral hemispheres to acupuncture compared to baseline. Also, interhemispheric inhibition from the contralateral motor cortex to the opposite showed a significant decline. The results indicated that corticomotoneuronal excitability and interhemispheric competition could be modulated by acupuncture therapy on healthy subjects. The following question about whether these changes will be observed in the same way on stroke patients and whether they correlate with the therapeutic effect on movement need to be answered by following studies. This trial is registered with ISRCTN13074245.

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Changes in interhemispheric inhibition from active to resting primary motor cortex during a fine-motor manipulation task

Journal of Neurophysiology ◽

10.1152/jn.00888.2011 ◽

2012 ◽

Vol 107 (11) ◽

pp. 3086-3094 ◽

Cited By ~ 16

Author(s):

Takuya Morishita ◽

Kazumasa Uehara ◽

Kozo Funase

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

Conditioning Stimulus ◽

Fine Motor ◽

Interhemispheric Inhibition ◽

Left Hand ◽

Resting Motor Threshold ◽

Inhibitory Circuit ◽

Task Conditions

The effect of performance of a sensorimotor task on the interhemispheric inhibition (IHI) induced from the active primary motor cortex (M1) to the resting M1 was examined in 10 right-handed subjects. Transcranial magnetic stimulation (TMS) was performed to produce motor evoked potentials (MEP) in the resting right (Rt)-first dorsal interosseous (FDI). For the paired-TMS paradigm, a conditioning stimulus (CS) was delivered to the Rt-M1, and its intensity was adjusted from 0.6 to 1.4 times the resting motor threshold of the MEP in the left (Lt)-FDI in 0.2 steps. The test stimulus was delivered to the Lt-M1, and its intensity was adjusted to evoke similar MEP amplitudes in the Rt-FDI among the task conditions. The interstimulus interval was fixed at 10 ms. As a sensorimotor task, a fine-motor manipulation (FM) task (using chopsticks to pick up, transport, and release glass balls) was adopted. In addition, an isometric abduction (IA) task was also performed as a control task. These tasks were carried out with the left hand. The IHI from the active to the resting M1 observed during the FM task was markedly increased compared with that induced during the IA task, and this effect was not dependent on the MEP amplitude evoked in the active Lt-FDI by the CS. The present findings suggest that the increased IHI from the active to the resting M1 observed during the FM task was linked to reductions in the activity of the ipsilateral intracortical inhibitory circuit, as we reported previously.

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Paradoxical facilitation alongside interhemispheric inhibition

Experimental Brain Research ◽

10.1007/s00221-021-06183-9 ◽

2021 ◽

Author(s):

Michel Belyk ◽

Russell Banks ◽

Anna Tendera ◽

Robert Chen ◽

Deryk S. Beal

Keyword(s):

Motor Cortex ◽

Corpus Callosum ◽

Primary Motor Cortex ◽

Conditioning Stimulus ◽

Future Research ◽

Homologous Region ◽

Inhibitory Influence ◽

Interhemispheric Inhibition ◽

Opposite Hemisphere ◽

Surprising Effect

AbstractNeurophysiological experiments using transcranial magnetic stimulation (TMS) have sought to probe the function of the motor division of the corpus callosum. Primary motor cortex sends projections via the corpus callosum with a net inhibitory influence on the homologous region of the opposite hemisphere. Interhemispheric inhibition (IHI) experiments probe this inhibitory pathway. A test stimulus (TS) delivered to the motor cortex in one hemisphere elicits motor evoked potentials (MEPs) in a target muscle, while a conditioning stimulus (CS) applied to the homologous region of the opposite hemisphere modulates the effect of the TS. We predicted that large CS MEPs would be associated with increased IHI since they should be a reliable index of how effectively contralateral motor cortex was stimulated and therefore of the magnitude of interhemispheric inhibition. However, we observed a strong tendency for larger CS MEPs to be associated with reduced interhemispheric inhibition which in the extreme lead to a net effect of facilitation. This surprising effect was large, systematic, and observed in nearly all participants. We outline several hypotheses for mechanisms which may underlie this phenomenon to guide future research.

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Modulation of Cortical Activity by High-Frequency Whole-Body Vibration Exercise: An fNIRS Study

Journal of Sport Rehabilitation ◽

10.1123/jsr.2017-0012 ◽

2019 ◽

Vol 28 (7) ◽

pp. 665-670 ◽

Cited By ~ 3

Author(s):

Dong-Sung Choi ◽

Hwang-Jae Lee ◽

Yong-II Shin ◽

Ahee Lee ◽

Hee-Goo Kim ◽

...

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Whole Body Vibration ◽

Hemoglobin Concentration ◽

Cortical Activity ◽

Cortical Activation ◽

Whole Body ◽

Body Vibration ◽

Cortical Areas ◽

Vibration Condition

Context: Whole-body vibration (WBV) has shown many positive effects on the human body in rehabilitation and clinical settings in which vibration has been used to elicit muscle contractions in spastic and paretic muscles. Objective: The purpose of this study was to investigate whether WBV exercise (WBVe) differently modulates the cortical activity associated with motor and prefrontal function based on its frequency. Methods: A total of 18 healthy male adults (mean age: 25.3 [2.4] y) participated in this study and performed WBVe (Galileo Advanced plus; Novotec Medical, Pforzheim, Germany) under 3 different vibration frequency conditions (4-mm amplitude with 10-, 20-, and 27-Hz frequencies) and a control condition (0-mm amplitude with 0-Hz frequency). Each condition consisted of 2 alternating tasks (squatting and standing) every 30 seconds for 5 repetitions. All subjects performed the 4 conditions in a randomized order. Main Outcome Measure: Cortical activation during WBVe was measured by relative changes in oxygenated hemoglobin concentration over the primary motor cortex, premotor cortex, supplementary motor area, and prefrontal and somatosensory cortices using functional near-infrared spectroscopy. Results: Oxygenated hemoglobin concentration was higher during the 27-Hz vibration condition than the control and 10-Hz vibration conditions. Specifically, these changes were pronounced in the bilateral primary motor cortex (P < .05) and right prefrontal cortex (P < .05). In contrast, no significant changes in oxygenated hemoglobin concentration were observed in any of the cortical areas during the 10-Hz vibration condition compared with the control condition. Conclusion: This study provides evidence that the motor network and prefrontal cortical areas of healthy adult males can be activated by 27-Hz WBVe. However, WBVe at lower frequencies did not induce significant changes in cortical activation.

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Intermanual Differences in Movement-related Interhemispheric Inhibition

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2007.19.2.204 ◽

2007 ◽

Vol 19 (2) ◽

pp. 204-213 ◽

Cited By ~ 151

Author(s):

Julie Duque ◽

Nagako Murase ◽

Pablo Celnik ◽

Friedhelm Hummel ◽

Michelle Harris-Love ◽

...

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Critical Role ◽

Hand Movements ◽

Dominant Hand ◽

Interhemispheric Inhibition ◽

Movement Onset ◽

Nondominant Hand ◽

Long Time ◽

The Right

Interhemispheric inhibition (IHI) between motor cortical areas is thought to play a critical role in motor control and could influence manual dexterity. The purpose of this study was to investigate IHI preceding movements of the dominant and nondominant hands of healthy volunteers. Movement-related IHI was studied by means of a double-pulse transcranial magnetic stimulation protocol in right-handed individuals in a simple reaction time paradigm. IHI targeting the motor cortex contralateral (IHIc) and ipsilateral (IHIi) to each moving finger was determined. IHIc was comparable after the go signal, a long time preceding movement onset, in both hands. Closer to movement onset, IHIc reversed into facilitation for the right dominant hand but remained inhibitory for left nondominant hand movements. IHIi displayed a nearly constant inhibition with a trough early in the premovement period in both hands. In conclusion, our results unveil a more important modulation of interhemispheric interactions during generation of dominant than nondominant hand movements. This modulation essentially consisted of a shift from a balanced IHI at rest to an IHI predominantly directed toward the ipsilateral primary motor cortex at movement onset. Such a mechanism might release muscles from inhibition in the contralateral primary motor cortex while preventing the occurrence of the mirror activity in ipsilateral primary motor cortex and could therefore contribute to intermanual differences in dexterity.

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Motor Cortex Activation During Writing in Focal Upper-Limb Dystonia: An fNIRS Study

Neurorehabilitation and Neural Repair ◽

10.1177/15459683211019341 ◽

2021 ◽

pp. 154596832110193

Author(s):

Renata Prôa ◽

Joana Balardin ◽

Danilo D. de Faria ◽

Artur M. Paulo ◽

João R. Sato ◽

...

Keyword(s):

Motor Cortex ◽

Upper Limb ◽

Near Infrared ◽

Primary Motor Cortex ◽

Brain Regions ◽

Control Group ◽

Functional Near Infrared Spectroscopy ◽

Physical Constraints ◽

Cortical Areas ◽

Writing Task

Background Functional imaging studies have associated dystonia with abnormal activation in motor and sensory brain regions. Commonly used techniques such as functional magnetic resonance imaging impose physical constraints, limiting the experimental paradigms. Functional near-infrared spectroscopy (fNIRS) offers a new noninvasive possibility for investigating cortical areas and the neural correlates of complex motor behaviors in unconstrained settings. Methods We compared the cortical brain activation of patients with focal upper-limb dystonia and controls during the writing task under naturalistic conditions using fNIRS. The primary motor cortex (M1), the primary somatosensory cortex (S1), and the supplementary motor area were chosen as regions of interest (ROIs) to assess differences in changes in both oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb) between groups. Results Group average activation maps revealed an expected pattern of contralateral recruitment of motor and somatosensory cortices in the control group and a more bilateral pattern of activation in the dystonia group. Between-group comparisons focused on specific ROIs revealed an increased activation of the contralateral M1 and S1 cortices and also of the ipsilateral M1 cortex in patients. Conclusions Overactivity of contralateral M1 and S1 in dystonia suggest a reduced specificity of the task-related cortical areas, whereas ipsilateral activation possibly indicates a primary disorder of the motor cortex or an endophenotypic pattern. To our knowledge, this is the first study using fNIRS to assess cortical activity in dystonia during the writing task under natural settings, outlining the potential of this technique for monitoring sensory and motor retraining in dystonia rehabilitation.

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Modulation of Fibers to Motor Cortex during Thalamic DBS in Tourette Patients Correlates with Tic Reduction

Brain Sciences ◽

10.3390/brainsci10050302 ◽

2020 ◽

Vol 10 (5) ◽

pp. 302 ◽

Cited By ~ 1

Author(s):

Pablo Andrade ◽

Petra Heiden ◽

Moritz Hoevels ◽

Marc Schlamann ◽

Juan C. Baldermann ◽

...

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Supplementary Motor Area ◽

Diffusion Tensor ◽

Regions Of Interest ◽

Motor Area ◽

Probabilistic Tractography ◽

Cortical Areas ◽

Centromedian Nucleus ◽

Deep Brain

Probabilistic tractography in Tourette syndrome (TS) patients have shown an alteration in the connectivity of the primary motor cortex and supplementary motor area with the striatum and thalamus, suggesting an abnormal connectivity of the cortico-striatum-thalamocortical-pathways in TS. Deep brain stimulation (DBS) of the centromedian nucleus–nucleus ventrooralis internus (CM-Voi complex) in the thalamus is an effective treatment for refractory TS patients. We investigated the connectivity of activated fibers from CM-Voi to the motor cortex and its correlation between these projections and their clinical outcome. Seven patients with TS underwent CM-Voi-DBS surgery and were clinically evaluated preoperatively and six months postoperatively. We performed diffusion tensor imaging to display the activated fibers projecting from the CM-Voi to the different motor cortex regions of interest. These analyses showed that the extent of tic reduction during DBS is associated with the degree of stimulation-dependent connectivity between CM-Voi and the motor cortex, and in particular, an increased density of projections to the presupplementary motor area (preSMA). Non-responder patients displayed the largest amount of active fibers projecting into cortical areas other than motor cortex compared to responder patients. These findings support the notion that an abnormal connectivity of thalamocortical pathways underlies TS, and that modulation of these circuits through DBS could restore the function and reduce symptoms.

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Short- and long-latency interhemispheric inhibitions are additive in human motor cortex

Journal of Neurophysiology ◽

10.1152/jn.00960.2012 ◽

2013 ◽

Vol 109 (12) ◽

pp. 2955-2962 ◽

Cited By ~ 4

Author(s):

Soumya Ghosh ◽

Arpan R. Mehta ◽

Guan Huang ◽

Carolyn Gunraj ◽

Tasnuva Hoque ◽

...

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Neural Circuits ◽

Motor Evoked Potentials ◽

Conditioning Stimulus ◽

Interhemispheric Inhibition ◽

Human Motor Cortex ◽

Inhibitory Processes ◽

Long Latency ◽

The Right

Transcranial magnetic stimulation (TMS) of the human primary motor cortex (M1) at suprathreshold strength results in inhibition of M1 in the opposite hemisphere, a process termed interhemispheric inhibition (IHI). Two phases of IHI, termed short-latency interhemispheric inhibition (SIHI) and long-latency interhemispheric inhibition (LIHI), involving separate neural circuits, have been identified. In this study we evaluated how these two inhibitory processes interact with each other. We studied 10 healthy right-handed subjects. A test stimulus (TS) was delivered to the left M1, and motor evoked potentials (MEPs) were recorded from the right first dorsal interosseous (FDI) muscle. Contralateral conditioning stimuli (CCS) were applied to the right M1 either 10 ms or 50 ms prior to the TS, inducing SIHI and LIHI, respectively, in the left M1. The effects of SIHI and LIHI alone, and SIHI and LIHI delivered together, were compared. The TS was adjusted to produce 1-mV or 0.5-mV MEPs when applied alone or after CCS. SIHI and LIHI were found to be additive when delivered together, irrespective of the strength of the TS. The interactions were affected neither by varying the strength of the conditioning stimulus producing SIHI nor by altering the current direction of the TS. Small or opposing interactions, however, may not have been detected. These results support previous findings suggesting that SIHI and LIHI act through different neural circuits. Such inhibitory processes may be used individually or additively during motor tasks and should be studied as separate processes in functional studies.

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