Inhibition of ipsilateral motor cortex during phasic generation of low force

Liepert, Joachim; Dettmers, Christian; Terborg, C.; Weiller, Cornelius

doi:10.1016/s1388-2457(00)00503-4

Cited by 164 publications

(114 citation statements)

References 46 publications

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“…This conclusion is in tune with the view that intracortical function associated with performance of unimanual motor tasks relies on an active and often discrete interaction between both M1s (Murase et al, 2004;Duque et al, 2005Duque et al, , 2007, although differences may be seen between movements of the dominant and nondominant hand (Liepert et al, 2001;Ziemann and Hallett, 2001;Vines et al, 2006;Duque et al, 2007). On one side, our results show that a strong unimanual movement provides extra excitation to the M1 ipsilateral in the absence of involuntary EMG activity in the contralateral resting arm.…”

Section: Ihi From M1 Contralateral To M1 Ipsilateralsupporting

confidence: 90%

“…Previous studies showed that performance of high levels of force with one hand results in an increase in corticomotor excitability targeting the contralateral resting hand (Hess et al, 1986;Meyer et al, 1995;Stedman et al, 1998;Tinazzi and Zanette, 1998;Muellbacher et al, 2000;Hortobagyi et al, 2003), whereas performance of low levels of force led to conflicting results: facilitation, inhibition, or no changes (Hess et al, 1986;Stedman et al, 1998;Liepert et al, 2001;Sohn et al, 2003). These results raised the untested hypothesis that the mechanisms within the primary motor cortex controlling corticospinal output to a resting hand may differ in an activity-dependent manner.…”

Section: Discussionmentioning

confidence: 99%

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Mechanisms Underlying Functional Changes in the Primary Motor Cortex Ipsilateral to an Active Hand

Pérez¹,

Cohen²

2008

J. Neurosci.

245

256

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Performance of a unimanual hand motor task results in functional changes in both primary motor cortices (M1 ipsilateral and M1 contralateral ). The neuronal mechanisms controlling the corticospinal output originated in M1 ipsilateral and the resting hand during a unimanual task remain unclear. Here, we assessed functional changes within M1 ipsilateral and in interhemispheric inhibition (IHI) associated with parametric increases in unimanual force. We measured motor-evoked potential (MEP) recruitment curves (RCs) and shortinterval intracortical inhibition (SICI) in M1 ipsilateral , IHI from M1 contralateral to M1 ipsilateral , and the influence of IHI over SICI using transcranial magnetic stimulation at rest and during 10, 30, and 70% of maximal right wrist flexion force. EMG from the left resting flexor carpi radialis (FCR) muscle was comparable across conditions. Left FCR MEP RCs increased, and SICI decreased with increasing right wrist force. Activity-dependent (rest and 10, 30, and 70%) left FCR maximal MEP size correlated with absolute changes in SICI. IHI decreased with increasing force at matched conditioned MEP amplitudes. IHI and SICI were inversely correlated at increasing forces. In the presence of IHI, SICI decreased at rest and 70% force. In summary, we found activity-dependent changes in (1) SICI in M1 ipsilateral , (2) IHI from M1 contralateral to M1 ipsilateral , and (3) the influence of IHI over SICI in the left resting hand during force generation by the right hand. Our findings indicate that interactions between GABAergic intracortical circuits mediating SICI and interhemispheric glutamatergic projections between M1s contribute to control activity-dependent changes in corticospinal output to a resting hand during force generation by the opposite hand.

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Section: Ihi From M1 Contralateral To M1 Ipsilateralsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Mechanisms Underlying Functional Changes in the Primary Motor Cortex Ipsilateral to an Active Hand

Pérez¹,

Cohen²

2008

J. Neurosci.

245

256

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“…The data are consistent with Parlow and Kinsbourne's (1989) cross-activation hypothesis, which suggests that during motor learning, task-relevant information is simultaneously stored in both the trained and untrained hemispheres (see also Cramer et al 1999;Dettmers et al 1995). Transcranial magnetic stimulation (TMS) studies have also shown that activation of one limb results in contraction intensity-dependent excitability changes of the pathways projecting to the opposite limb (e.g., Hess et al 1986;Liepert et al 2001); the stronger the contraction of one limb, the greater the change in excitability observed in the projections to the opposite limb (Perez and Cohen 2008).…”

Section: In the Present Study We Observed That Noninvasive Brain Stimsupporting

confidence: 74%

Motor learning and cross-limb transfer rely upon distinct neural adaptation processes

Stöckel

Carroll

Summers

et al. 2016

Journal of Neurophysiology

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Performance benefits conferred in the untrained limb after unilateral motor practice are termed cross-limb transfer. Although the effect is robust, the neural mechanisms remain incompletely understood. In this study we used noninvasive brain stimulation to reveal that the neural adaptations that mediate motor learning in the trained limb are distinct from those that underlie cross-limb transfer to the opposite limb. Thirty-six participants practiced a ballistic motor task with their right index finger (150 trials), followed by intermittent theta-burst stimulation (iTBS) applied to the trained (contralateral) primary motor cortex (cM1 group), the untrained (ipsilateral) M1 (iM1 group), or the vertex (sham group). After stimulation, another 150 training trials were undertaken. Motor performance and corticospinal excitability were assessed before motor training, pre-and post-iTBS, and after the second training bout. For all groups, training significantly increased performance and excitability of the trained hand, and performance, but not excitability, of the untrained hand, indicating transfer at the level of task performance. The typical facilitatory effect of iTBS on MEPs was reversed for cM1, suggesting homeostatic metaplasticity, and prior performance gains in the trained hand were degraded, suggesting that iTBS interfered with learning. In stark contrast, iM1 iTBS facilitated both performance and excitability for the untrained hand. Importantly, the effects of cM1 and iM1 iTBS on behavior were exclusive to the hand contralateral to stimulation, suggesting that adaptations within the untrained M1 contribute to crosslimb transfer. However, the neural processes that mediate learning in the trained hemisphere vs. transfer in the untrained hemisphere appear distinct. ballistic motor learning; interlimb transfer; noninvasive brain stimulation; corticospinal excitability; motor performance

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“…Several evidences suggested that the interhemispheric communication between M1s plays a major role in the control of unimanual hand movements and that the strength of these connections are dependent on the arm use. Indeed, during the execution of unimanual finger movements, the contralateral M1 inhibits deeper the ipsilateral one through the transcallosal pathway (Duque et al, 2007), inducing a decrease of ipsilateral M1 excitability (Liepert et al, 2001). Furthermore, studies in patients with stroke in motor areas reported an increase of activity in the intact M1 (Liepert et al, 2000) and an abnormally high IHI from the intact to the damaged M1, more prominent in cases with greater motor impairment (Murase et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Use-Dependent Hemispheric Balance

Avanzino¹,

Bassolino²,

Pozzo³

et al. 2011

J. Neurosci.

108

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In the human brain, homologous regions of the primary motor cortices (M1s) are connected through transcallosal fibers. Interhemispheric communication between the two M1s plays a major role in the control of unimanual hand movements, and the strength of this connection seems to be dependent on arm activity. For instance, a lesion in the M1 can induce an increase in the excitability of the intact M1 and an abnormal high inhibitory influence onto the damaged M1. This can be attributable to either the disuse of the affected limb or the overuse of the unaffected one. Here, to directly investigate cortical modifications induced by an abnormal asymmetric use of the two limbs, we studied both the excitability of the two M1s and transcallosal interaction between them in healthy subjects whose right hand was immobilized for 10 h. The left "not-immobilized" arm was completely free to move in one group of participants (G1) and limited in the other one (G2). We found that the non-use reduced the excitability of the left M1 and decreased the inhibitory influence onto the right hemisphere in the two groups. However, an increase in the excitability of right M1 and a deeper inhibitory interaction onto the left hemisphere were evident only in G1. Thus, modifications in the right M1 were not directly produced by the non-use but would depend on the overuse of the "not-immobilized" arm. Our findings suggest that the balance between the two M1s is strongly use dependent.

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Inhibition of ipsilateral motor cortex during phasic generation of low force

Cited by 164 publications

References 46 publications

Mechanisms Underlying Functional Changes in the Primary Motor Cortex Ipsilateral to an Active Hand

Mechanisms Underlying Functional Changes in the Primary Motor Cortex Ipsilateral to an Active Hand

Motor learning and cross-limb transfer rely upon distinct neural adaptation processes

Use-Dependent Hemispheric Balance

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