Voluntary teeth clenching facilitates human motor system excitability | Semantic Scholar (2024)

Investigating the responses of motor evoked potentials elicited by transcranial magnetic stimulation with selected current directions and by brainstem magnetic stimulation found inhibitory effects of VTC in FDI muscle were more potent than those in ADM or APB muscles, suggesting that the modulations of MEP were attributed to the cortical origin.

The results suggest that the performance of repeated TCTs can trigger neuroplastic changes in the corticomotor control of the jaw-closing muscles and that such neuroplastics changes may contribute to the mechanism underlying the clinical manifestations of tooth clenching.

The findings suggest that phasic muscle contraction in the remote segment results in a decrease in intracortical inhibitory pathways to the corticospinal tract innervating the muscle involved in reflex testing and that the remote effect on the CSP is predominantly cortical in origin.

The results suggest that facilitation occurs in the hand motor area at the early phase of teeth clenching, and spinal facilitation dominates at its late phase, and this time course of facilitation may indicate that the motor cortex must regulate hand muscles finely at theEarly phase of tooth clenching and spinal cord may stabilize them firmly at the late phase.

Both execution and preparation of combined motor tasks led to higher excitability than individual tasks, which extend the current understanding of the neural interactions underlying simultaneous contraction of muscles in different body parts.

The results of the present study demonstrate that oral motor activity exerts strong influences on the motor activity of the forearm as well as in association with voluntary teeth clenching.

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It is concluded that the soleus H reflex is facilitated in association with voluntary teeth clenching, and that descending influences from the cerebral cortex, as well as peripheral afferent impulses from the oral-facial region, are involved in this facilitation.

It is concluded that at least two distinct mechanisms act sequentially in the facilitation of the tendon reflex of quadriceps, and a slowly-travelling rostro-caudal facilitation is postulated during phase II when thefacilitation is related to afferents coming from the contracting muscle.

It is concluded that transcranial stimulation over the lateral part of the motor cortex of one hemisphere can suppress the excitability of the contralateral motor cortex.

R2 amplitudes linearly increased with the increasing pre-innervation levels, possibly reflecting recruitment of a greater number of motor units for the late component or a postponement of motoneuron synchronization of theLate component.

It is concluded that magnetic brainstem stimulation produces a single descending volley in the corticospinal tract at the foramen magnum level with less discomfort.

It is suggested that voluntary drive reduces the excitability of inhibitory circuits in cortical areas that project to the active muscle in a relaxed target muscle.

In ten normal volunteers, a transcranial magnetic or electric stimulus that was subthreshold for evoking an EMG response in relaxed muscles was used to condition responses evoked by a later, suprathreshold magnetic orElectric test shock to suggest that the suppression was produced by an action on cortical, rather than spinal excitability.

The findings suggest that the intracortical mechanisms for inhibition and facilitation in different motor representations are not related to the strength of corticospinal projections.

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