scholarly journals Distinct neural mechanisms support different forms of inner speech

2021 ◽  
Author(s):  
Ladislas Nalborczyk ◽  
Marieke Longcamp ◽  
Mireille Bonnard ◽  
Laure Spieser ◽  
F.-Xavier Alario
Keyword(s):  
Memory Retrieval ◽  
Magnetic Stimulation ◽  
Motor System ◽  
Primary Motor Cortex ◽  
Neural Mechanisms ◽  
Inner Speech ◽  
Retrieval Process ◽  
Speech Motor ◽  
Multisensory Experience ◽  
Stimulation Of

Humans have the ability to mentally examine speech. This covert form of speech production is often accompanied by sensory (e.g., auditory) percepts. However, the cognitive and neural mechanisms that generate these percepts are still debated. According to a prominent proposal, inner speech has at least two distinct phenomenological components: inner speaking and inner hearing. Here we use transcranial magnetic stimulation to test whether these two phenomenologically distinct processes are supported by distinct cerebral mechanisms. We hypothesise that inner speaking relies more strongly on an online motor-to-sensory simulation that constructs a multisensory experience, whereas inner hearing relies more strongly on a memory-retrieval process, where the multisensory experience is reconstructed from stored motor-to-sensory associations. We predict that the speech motor system will be involved more strongly during inner speaking than inner hearing. This will be revealed by modulations of TMS evoked responses at muscle level following cortical stimulation of the lip primary motor cortex.

Multifocal Noninvasive Magnetic Stimulation of the Primary Motor Cortex in Type 1 Myotonic Dystrophy –A Proof of Concept Pilot Study

2021 ◽  
pp. 1-10
Author(s):  
Ericka Greene ◽  
Jason Thonhoff ◽  
Blessy S. John ◽  
David B. Rosenfield ◽  
Santosh A. Helekar
Keyword(s):  
Motor Cortex ◽  
Myotonic Dystrophy ◽  
Muscle Function ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Compound Muscle Action Potential ◽  
Sham Stimulation ◽  
Stimulation Of

Background: Repeated neuromuscular electrical stimulation in type 1 Myotonic Dystrophy (DM1) has previously been shown to cause an increase in strength and a decrease in hyperexcitability of the tibialis anterior muscle. Objective: In this proof-of-principle study our objective was to test the hypothesis that noninvasive repetitive transcranial magnetic stimulation of the primary motor cortex (M1) with a new portable wearable multifocal stimulator causes improvement in muscle function in DM1 patients. Methods: We performed repetitive stimulation of M1, localized by magnetic resonance imaging, with a newly developed Transcranial Rotating Permanent Magnet Stimulator (TRPMS). Using a randomized within-patient placebo-controlled double-blind TRPMS protocol, we performed unilateral active stimulation along with contralateral sham stimulation every weekday for two weeks in 6 adults. Methods for evaluation of muscle function involved electromyography (EMG), hand dynamometry and clinical assessment using the Medical Research Council scale. Results: All participants tolerated the treatment well. While there were no significant changes clinically, EMG showed significant improvement in nerve stimulus-evoked compound muscle action potential amplitude of the first dorsal interosseous muscle and a similar but non-significant trend in the trapezius muscle, after a short exercise test, with active but not sham stimulation. Conclusions: We conclude that two-week repeated multifocal cortical stimulation with a new wearable transcranial magnetic stimulator can be safely conducted in DM1 patients to investigate potential improvement of muscle strength and activity. The results obtained, if confirmed and extended by future safety and efficacy trials with larger patient samples, could offer a potential supportive TRPMS treatment in DM1.

The effect of transcranial magnetic stimulation on the excitability of the motor neuron pools of the muscles of the lower extremities

2021 ◽  
Author(s):  
S.S. Ananiev ◽  
D.A. Pavlov ◽  
R.N. Yakupov ◽  
V.A. Golodnova ◽  
M.V. Balykin
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Lower Extremities ◽  
Transcutaneous Electrical Stimulation ◽  
Stimulation Of

The study was conducted on 22 healthy men aged 18-23 years. The primary motor cortex innervating the lower limb was stimulated with transcranial magnetic stimulation. Using transcutaneous electrical stimulation of the spinal cord, evoked motor responses of the muscles of the lower extremities were initiated when electrodes were applied cutaneous between the spinous processes in the Th11-Th12 projection. Research protocol: Determination of the thresholds of BMO of the muscles of the lower extremities during TESCS; determination of the BMO threshold of the TA muscle in TMS; determination of the thresholds of the BMO of the muscles of the lower extremities during TESCS against the background of 80% and 90% TMS. It was found that magnetic stimulation of the motor cortex of the brain leads to an increase in the excitability of the neural structures of the lumbar thickening of the spinal cord and an improvement in neuromuscular interactions. Key words: transcranial magnetic stimulation, transcutaneous electrical stimulation of the spinal cord, neural networks, excitability, neuromuscular interactions.

Enhancing Encoding of a Motor Memory in the Primary Motor Cortex By Cortical Stimulation

2004 ◽  
Vol 91 (5) ◽  
pp. 2110-2116 ◽  
Author(s):  
Cathrin M. Bütefisch ◽  
Vikram Khurana ◽  
Leonid Kopylev ◽  
Leonardo G. Cohen
Keyword(s):  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Temporal Relationship ◽  
Primary Motor Cortex ◽  
Motor Memory ◽  
Motor Training ◽  
Training Task ◽  
Plastic Process ◽  
And Training ◽  
Stimulation Of

Motor training results in encoding of motor memories, a form of use-dependent plasticity. Here we tested the hypothesis that transcranial magnetic stimulation (TMS) synchronously applied to a motor cortex engaged in a motor training task could enhance this plastic process. Healthy volunteers were studied in four sessions: training consisting of performance of directionally specific voluntary thumb movements ( Train alone), training with TMS delivered during the execution of the training movement in a strictly temporal relationship to the motor cortex contralateral ( Train+ TMS synchronouscontra) and ipsilateral ( Train+ TMS synchronousipsi) to the training hand, and training with TMS delivered asynchronous to the training movement to the motor cortex contralateral to the training hand ( Train+ TMS asynchronouscontra). Train alone, Train+ TMS synchronouscontra, and Train+ TMS asynchronouscontra but not Train+ TMS synchronousipsi elicited a clear motor memory. The longevity of the encoded memory was significantly enhanced by Train+ TMS synchronouscontra when compared with Train alone and Train+ TMS asynchronouscontra. Therefore use-dependent encoding of a motor memory can be enhanced by synchronous Hebbian stimulation of the motor cortex that drives the training task and reduced by stimulation of the homologous ipsilateral motor cortex, a result relevant for studies of cognitive and physical rehabilitation.

scholarly journals Stopping a response has global or nonglobal effects on the motor system depending on preparation

2012 ◽  
Vol 107 (1) ◽  
pp. 384-392 ◽  
Author(s):  
Ian Greenhouse ◽  
Caitlin L. Oldenkamp ◽  
Adam R. Aron
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Motor System ◽  
Primary Motor Cortex ◽  
Stop Signal ◽  
Stop Signal Task ◽  
Proactive Control ◽  
The Subject ◽  
Do So

Much research has focused on how people stop initiated response tendencies when instructed by a signal. Stopping of this kind appears to have global effects on the motor system. For example, by delivering transcranial magnetic stimulation (TMS) over the leg area of the primary motor cortex, it is possible to detect suppression in the leg when the hand is being stopped (Badry R et al. Suppression of human cortico-motoneuronal excitability during the stop-signal task. Clin Neurophysiol 120: 1717–1723, 2009). Here, we asked if such “global suppression” can be observed proactively, i.e., when people anticipate they might have to stop. We used a conditional stop signal task, which allows the measurement of both an “anticipation phase” (i.e., where proactive control is applied) and a “stopping” phase. TMS was delivered during the anticipation phase ( experiment 1) and also during the stopping phase ( experiments 1 and 2) to measure leg excitability. During the anticipation phase, we did not observe leg suppression, but we did during the stopping phase, consistent with Badry et al. (2009) . Moreover, when we split the subject groups into those who slowed down behaviorally (i.e., exercised proactive control) and those who did not, we found that subjects who slowed did not show leg suppression when they stopped, whereas those who did not slow did show leg suppression when they stopped. These results suggest that if subjects prepare to stop, then they do so without global effects on the motor system. Thus, preparation allows them to stop more selectively.

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