Differential Influence of the Dorsal Premotor and Primary Somatosensory Cortex on Corticospinal Excitability during Kinesthetic and Visual Motor Imagery: A Low-Frequency Repetitive Transcranial Magnetic Stimulation Study

Consistent evidence suggests that motor imagery involves the activation of several sensorimotor areas also involved during action execution, including the dorsal premotor cortex (dPMC) and the primary somatosensory cortex (S1). However, it is still unclear whether their involvement is specific for either kinesthetic or visual imagery or whether they contribute to motor activation for both modalities. Although sensorial experience during motor imagery is often multimodal, identifying the modality exerting greater facilitation of the motor system may allow optimizing the functional outcomes of rehabilitation interventions. In a sample of healthy adults, we combined 1 Hz repetitive transcranial magnetic stimulation (rTMS) to suppress neural activity of the dPMC, S1, and primary motor cortex (M1) with single-pulse TMS over M1 for measuring cortico-spinal excitability (CSE) during kinesthetic and visual motor imagery of finger movements as compared to static imagery conditions. We found that rTMS over both dPMC and S1, but not over M1, modulates the muscle-specific facilitation of CSE during kinesthetic but not during visual motor imagery. Furthermore, dPMC rTMS suppressed the facilitation of CSE, whereas S1 rTMS boosted it. The results highlight the differential pattern of cortico-cortical connectivity within the sensorimotor system during the mental simulation of the kinesthetic and visual consequences of actions.

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Repetitive Transcranial Magnetic Stimulation of the Primary Somatosensory Cortex Modulates Perception of the Tendon Vibration Illusion

Perceptual and Motor Skills ◽

10.1177/0031512516663715 ◽

2016 ◽

Vol 123 (2) ◽

pp. 424-444 ◽

Cited By ~ 3

Author(s):

D. C. Huh ◽

J. M. Lee ◽

S. M. Oh ◽

J-H. Lee ◽

P. Van Donkelaar ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Somatosensory Cortex ◽

Magnetic Stimulation ◽

Repetitive Transcranial Magnetic Stimulation ◽

Primary Somatosensory Cortex ◽

Tendon Vibration ◽

Stimulation Of

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Unravelling the modulation of intracortical inhibition during motor imagery: An adaptive threshold-hunting study

10.1101/846931 ◽

2019 ◽

Author(s):

Cécilia Neige ◽

Dylan Rannaud Monany ◽

Cathy M. Stinear ◽

Winston D. Byblow ◽

Charalambos Papaxanthis ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Motor Cortex ◽

Motor Imagery ◽

Magnetic Stimulation ◽

Primary Motor Cortex ◽

Short Interval ◽

Intracortical Inhibition ◽

Adaptive Threshold ◽

Mental Simulation ◽

The Right

AbstractMotor imagery (MI) is the mental simulation of an action without any apparent muscular contraction. By means of transcranial magnetic stimulation, few studies revealed a decrease of short-interval intracortical inhibition (SICI) within the primary motor cortex. However, this decrease is ambiguous, as one would expect greater inhibition during MI to prevent overt motor output. The current study investigated the extent of SICI modulation during MI through a methodological and a conceptual reconsideration of i) the importance of parameters to assess SICI (Exp.1) and ii) the inhibitory process within the primary motor cortex as an inherent feature of MI (Exp.2). Participants performed two tasks: 1) rest and 2) imagery of isometric abduction of the right index finger. Using transcranial magnetic stimulation, motor evoked potentials were elicited in the right first dorsal interosseous muscle. An adaptive threshold-hunting paradigm was used, where the stimulus intensity required to maintain a fixed motor evoked potential amplitude was quantified. To test SICI, we conditioned the test stimulus with a conditioning stimulus (CS) of different intensities. Results revealed an Intensity by Task interaction showing that SICI decreased during MI as compared to rest only for the higher CS intensity (Exp.1). At the lowest CS intensities, a Task main effect revealed that SICI increased during MI (Exp.2). SICI modulation during MI depends critically on the CS intensity. By optimising CS intensity, we have shown that SICI circuits may increase during MI, revealing a potential mechanism to prevent the production of a movement while the motor system is activated.HighlightsExcitatory and inhibitory neural processes interact during motor imagery, as the motor regions are activated but no movement is produced.The current study investigated the extent of short interval intracortical inhibition modulation (SICI) during motor imagery.When using optimal settings, SICI increased during motor imagery, likely to prevent the production of an overt movement.

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Preconditioning Repetitive Transcranial Magnetic Stimulation of Premotor Cortex Can Reduce But Not Enhance Short-Term Facilitation of Primary Motor Cortex

Journal of Neurophysiology ◽

10.1152/jn.00753.2007 ◽

2008 ◽

Vol 99 (2) ◽

pp. 564-570 ◽

Cited By ~ 28

Author(s):

A. Suppa ◽

M. Bologna ◽

F. Gilio ◽

C. Lorenzano ◽

J. C. Rothwell ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Motor Cortex ◽

Magnetic Stimulation ◽

Primary Motor Cortex ◽

Repetitive Transcranial Magnetic Stimulation ◽

Premotor Cortex ◽

Single Pulse ◽

Short Term ◽

Hand Muscles ◽

Term Potentiation

Short trains of suprathreshold 5-Hz repetitive transcranial magnetic stimulation (rTMS) over primary motor cortex (M1) evoke motor potentials (MEPs) in hand muscles that progressively increase in amplitude via a mechanism that is thought to be similar to short-term potentiation described in animal preparations. Long trains of subthreshold rTMS over dorsal premotor cortex (PMd) are known to affect the amplitude of single-pulse MEPs evoked from M1. We tested whether PMd-rTMS affects short-term facilitation in M1. We also explored the effect of PMd-rTMS on M1 responses evoked by single-pulse TMS of different polarities. We tested in 15 healthy subjects short-term facilitation in left M1 (10 suprathreshold TMS pulses at 5 Hz) after applying rTMS to left PMd (1,500 subthreshold pulses at 1 and 5 Hz). In a sample of subjects we delivered single-pulse TMS with different polarities and paired-pulse TMS at short intervals (SICI) after PMd-rTMS. Short-term facilitation in M1 was reduced after applying 1 Hz to PMd, but was unaffected after 5-Hz PMd-rTMS. PMd-rTMS with 1 Hz reduced the amplitude of MEPs evoked by monophasic posteroanterior (PA) or biphasic anteroposterior (AP)–PA but had little effect on MEPs by monophasic AP or biphasic PA–AP single-pulse TMS. PMd-rTMS left SICI unchanged. PMd-rTMS (1 Hz) reduces short-term facilitation in M1 induced by short 5-Hz trains. This effect is likely to be caused by reduced facilitation of I-wave inputs to corticospinal neurons.

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