Probing interhemispheric dorsal premotor-primary motor cortex interactions with threshold hunting transcranial magnetic stimulation

Calvert, Glenn H.M.; McMackin, Roisin; Carson, Richard G.

doi:10.1016/j.clinph.2020.07.020

Cited by 9 publications

(3 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For active motor threshold (AMT), an AP-induced current was delivered and a trial was deemed successful if the stimulus intensity elicited an MEP of at least 200 µV in amplitude, while the FDI was pre-activated to approximately 10% of the participant’s perceived maximum voluntary contraction. RMT was determined using an automated adaptive threshold-hunting paradigm in MATLAB (R2018b; MathWorks, Natick MA, USA) that adjusted TMS output intensity as required according to the PEST procedure (Calvert et al 2020 ). Adaptive threshold-hunting for AMT was performed using freeware (TMS Motor Threshold Assessment Tool; MTAT 2.0, F. Awiszus and J. Borckardt), which was more amenable to detecting thresholds in the presence of voluntary EMG.…”

Section: Methodsmentioning

confidence: 99%

Intracortical facilitation and inhibition in human primary motor cortex during motor skill acquisition

Cirillo

Ren

et al. 2022

Exp Brain Res

View full text Add to dashboard Cite

The primary motor cortex (M1) is critical for movement execution, but its role in motor skill acquisition remains elusive. Here, we examine the role of M1 intracortical circuits during skill acquisition. Paired-pulse transcranial magnetic stimulation (TMS) paradigms of short-interval intracortical facilitation (SICF) and inhibition (SICI) were used to assess excitatory and inhibitory circuits, respectively. We hypothesised that intracortical facilitation and inhibition circuits in M1 would be modulated to support acquisition of a novel visuomotor skill. Twenty-two young, neurologically healthy adults trained with their nondominant hand on a skilled and non-skilled sequential visuomotor isometric finger abduction task. Electromyographic recordings were obtained from the nondominant first dorsal interosseous (FDI) muscle. Corticomotor excitability, SICF, and SICI were examined before, at the midway point, and after the 10-block motor training. SICI was assessed using adaptive threshold-hunting procedures. Task performance improved after the skilled, but not non-skilled, task training, which likely reflected the increase in movement speed during training. The amplitudes of late SICF peaks were modulated with skilled task training. There was no modulation of the early SICF peak, SICI, and corticomotor excitability with either task training. There was also no association between skill acquisition and SICF or SICI. The findings indicate that excitatory circuitries responsible for the generation of late SICF peaks, but not the early SICF peak, are modulated in motor skill acquisition for a sequential visuomotor isometric finger abduction task.

show abstract

Section: Methodsmentioning

confidence: 99%

Intracortical facilitation and inhibition in human primary motor cortex during motor skill acquisition

Cirillo

Ren

et al. 2022

Exp Brain Res

View full text Add to dashboard Cite

show abstract

“…PEST uses a probabilistic method to estimate the minimum TMS test stimulus (TS) intensity needed to elicit MEPs of a defined amplitude, here 50 µV for the RMT, in 50% of trials. We used an automated PEST script, implemented in MATLAB 88 , that incorporates the PEST function from the MTAT2.0 programme 89 as described in 90 . The peak-to-peak amplitude of the MEP of the targeted muscle is calculated online and passed to the algorithm following pulse delivery.…”

Section: Tms-based Neurofeedback Training Sessionsmentioning

confidence: 99%

TMS-based neurofeedback training of mental finger individuation induces neuroplastic changes in the sensorimotor cortex

Odermatt,

Schulthess-Lutz,

Mihelj

et al. 2024

Preprint

Self Cite

View full text Add to dashboard Cite

Neurofeedback (NF) training based on motor imagery is increasingly used in neurorehabilitation with the aim to improve motor functions. However, the neuroplastic changes underpinning these improvements are poorly understood. Here, we used mental finger individuation, i.e., the selective facilitation of single finger representations without producing overt movements, as a model to study neuroplasticity induced by NF. To enhance mental finger individuation, we used transcranial magnetic stimulation (TMS)-based NF training. During motor imagery of individual finger movements, healthy participants were provided visual feedback on the size of motor evoked potentials, reflecting their finger-specific corticospinal excitability. We found that TMS-NF improved the top-down activation of finger-specific representations. First, intracortical inhibitory circuits in the primary motor cortex were tuned after training such that inhibition was selectively reduced for the finger that was mentally activated. Second, motor imagery finger representations in sensorimotor areas assessed with functional MRI became more distinct after training. Together, our results indicate that the neural underpinnings of finger individuation, a well-known model system for neuroplasticity, can be modified using TMS-NF guided motor imagery training. These findings demonstrate that TMS-NF induces neuroplasticity in the sensorimotor system, highlighting the promise of TMS-NF on the recovery of fine motor function.

show abstract

“…A number of studies conducted in resting human participants have found evidence for intrahemsipheric and interhemispheric inhibitory [21][22][23][24][25] and facilitatory [25][26][27][28] circuits between PMd and M1, which can be reliably indexed using dsTMS methods. As knowledge of the stimulation parameters required to probe specific inhibitory and excitatory circuits between PMd and M1 has grown, several studies have examined how these circuits are modulated during the preparation of action.…”

Section: Pmd-m1 Cortico-cortical Circuits During Motor Preparationmentioning

confidence: 99%

The role of PMd in voluntary motor control: insights from TMS research.

Denyer

Greenhouse²,

Boyd³

2022

Preprint

View full text Add to dashboard Cite

Transcranial magnetic stimulation (TMS) research has furthered understanding of human PMd function due to its unrivalled ability to measure the inhibitory and facilitatory influences of PMd over M1 in a temporally precise manner. Findings from TMS research indicate that PMd transiently modulates inhibitory output to effector representations within M1 during motor preparation depending on which effectors are selected for response, and that the timing of these modulations correlates with the cognitive demands of the task. In this review, we critically assess this literature within the context of prevailing theories of PMd function borne out of single/multi unit recording research in non-human primates. Through this process we identify gaps in the literature and propose future experiments to address lingering questions.

show abstract

Probing interhemispheric dorsal premotor-primary motor cortex interactions with threshold hunting transcranial magnetic stimulation

Cited by 9 publications

References 44 publications

Intracortical facilitation and inhibition in human primary motor cortex during motor skill acquisition

Intracortical facilitation and inhibition in human primary motor cortex during motor skill acquisition

TMS-based neurofeedback training of mental finger individuation induces neuroplastic changes in the sensorimotor cortex

The role of PMd in voluntary motor control: insights from TMS research.

Contact Info

Product

Resources

About