Cerebellar transcranial direct current stimulation disrupts neuroplasticity of intracortical motor circuits

Liao, Wei‐Yeh; Sasaki, Ryoki; Semmler, John G.; Opie, George M.

doi:10.1371/journal.pone.0271311

Cited by 8 publications

(12 citation statements)

References 59 publications

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“…For post‐intervention responses, previous work suggests that increased facilitation following iTMS correlates with the increased response to single pulse stimulation and that this relationship cancels the effects of iTMS on SICF if the post‐intervention single‐pulse MEPs are used to normalise post‐intervention SICF values (Cash et al, 2009). As Spearman's rank correlation test revealed a similar relationship within the data of the current study (Experiment 1: rho = .6, P = .02; Experiment 2: rho = .5, P = .03; Experiment 3: rho = .9, P < .01), individual post‐intervention SICF trials were instead expressed relative to the mean pre‐intervention single‐pulse MEP (Cash et al, 2009; Liao et al, 2022; Opie et al, 2021). MEP amplitudes recorded during iTMS were averaged over 10 consecutive stimuli, resulting in a total of 12 blocks in Experiment 1 and 6 blocks in Experiments 2 and 3.…”

Section: Methodssupporting

confidence: 80%

Effect of current direction and muscle activation on motor cortex neuroplasticity induced by repetitive paired‐pulse transcranial magnetic stimulation

Sasaki,

Liao,

Opie

et al. 2023

Eur J of Neuroscience

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Repetitive paired‐pulse transcranial magnetic stimulation (TMS) at indirect (I)‐wave periodicity (iTMS) can increase plasticity in primary motor cortex (M1). Both TMS coil orientation and muscle activation can influence I‐wave activity, but it remains unclear how these factors influence M1 plasticity with iTMS. We therefore investigated the influence of TMS coil orientation and muscle activation on the response to iTMS. Thirty‐two young adults (24.2 ± 4.8 years) participated in three experiments. Each experiment included two sessions using a modified iTMS intervention with either a posterior–anterior orientation (PA) or anterior–posterior (AP) coil orientation over M1. Stimulation was applied in resting (Experiments 1 and 3) or active muscle (Experiments 2 and 3). Effects of iTMS on M1 excitability were assessed by recording motor evoked potentials (MEPs) and short‐interval intracortical facilitation (SICF) with PA and AP orientations in both resting (all experiments) and active (Experiment 2) muscle. For the resting intervention, MEPs were greater after AP iTMS (Experiment 1, P = .046), whereas SICF was comparable between interventions (all P > .10). For the active intervention, responses did not vary between PA and AP iTMS (Experiment 2, all P > .14), and muscle activation reduced the effect of AP iTMS during the intervention (Experiment 3, P = .002). Coil orientation influenced the MEP response after iTMS, and muscle activation reduced the response during iTMS. While this suggests that AP iTMS may be beneficial in producing a neuroplastic modulation of I‐wave circuits in resting muscle, further exploration of factors such as dosing is required.

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Section: Methodssupporting

confidence: 80%

Effect of current direction and muscle activation on motor cortex neuroplasticity induced by repetitive paired‐pulse transcranial magnetic stimulation

Sasaki,

Liao,

Opie

et al. 2023

Eur J of Neuroscience

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“…While the specific reason this was apparent in the current but not previous studies remains unclear, it nonetheless demonstrates the need for an improved sham paradigm for iTMS. We have previously used sham stimulation that involved paired-pulse stimuli with ISIs associated with non-facilitatory periods of the I-wave recruitment profile, the order of which are pseudorandomised between trials (Liao et al ., 2022). While this appears to be a promising approach, it has only been applied during application of cerebellar tDCS and will therefore need to be verified during isolated application to M1.…”

Section: Discussionmentioning

confidence: 99%

Investigating the effects of repetitive paired-pulse transcranial magnetic stimulation on visuomotor training using TMS-EEG

Sasaki,

Hand,

Liao

et al. 2024

Preprint

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ObjectivesI-wave periodicity repetitive paired-pulse transcranial magnetic stimulation (iTMS) can modify acquisition of a novel motor skill, but the associated neurophysiological effects remain unclear. The current study therefore used combined TMS-electroencephalography (TMS-EEG) to investigate the neurophysiological effects of iTMS on subsequent visuomotor training (VT).MethodsSixteen young adults (26.1 ± 5.1 years) participated in three sessions including real iTMS and VT (iTMS + VT), control iTMS and VT (iTMSsham+ VT), or iTMS alone. Motor-evoked potentials (MEPs) and TMS-evoked potentials (TEPs) were measured before and after iTMS, and again after VT, to assess neuroplastic changes.ResultsIrrespective of the intervention, MEP amplitude was not changed after iTMS or VT (P= 0.211). Motor skill was improved compared with baseline (P< 0.001), but no differences were found between stimulus conditions. In contrast, the P30 peak was altered by VT when preceded by sham iTMS (P< 0.05), but this effect was not apparent when VT was preceded by iTMS or following iTMS alone (allP> 0.15).ConclusionIn contrast to expectations, iTMS was unable to modulate MEP amplitude or influence motor learning. Despite this, changes in P30 amplitude suggested that motor learning was associated with altered cortical reactivity. Furthermore, this effect was abolished by priming with iTMS, suggesting an influence of priming that failed to impact learning.Authorship statementsConceptualization: JGS; Data curation: RS, BJH, and WL; Formal analysis: RS; Funding acquisition: RS; Investigation: RS, BJH, and WL; Methodology: RS, GMO, BJH and JGS; Project administration: GMO and JGS; Supervision: GMO and JGS; Roles/Writing - original draft: RS and GMO; Writing - review & editing: BJH, WL, and JGS.

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“…For baseline measures of SICF, individual paired‐pulse MEP amplitude was expressed as a percentage of the mean MEP amplitude produced by single‐pulse TMS in the same block. For all post‐iTBS measures of SICF, individual MEP amplitudes produced by paired‐pulse TMS were expressed as a percentage of the mean MEP amplitude produced by single‐pulse TMS recorded at baseline, as undertaken previously (Cash et al., 2009 ; Liao et al., 2022 ; Opie et al., 2021 ). This was performed because the increase in post‐intervention single‐pulse MEP amplitude is correlated with the increase in post‐intervention SICF, and normalising to the post‐intervention test MEP amplitude underestimates the change in excitability of the I‐wave generating networks (Cash et al., 2009 ).…”

Section: Methodsmentioning

confidence: 99%

Modulation of dorsal premotor cortex differentially influences I‐wave excitability in primary motor cortex of young and older adults

Liao

Opie

Ziemann

et al. 2023

The Journal of Physiology

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Previous research using transcranial magnetic stimulation (TMS) has demonstrated weakened connectivity between dorsal premotor cortex (PMd) and motor cortex (M1) with age. While this alteration is probably mediated by changes in the communication between the two regions, the effect of age on the influence of PMd on specific indirect (I) wave circuits within M1 remains unclear. The present study therefore investigated the influence of PMd on early and late I‐wave excitability in M1 of young and older adults. Twenty‐two young (mean ± SD, 22.9 ± 2.9 years) and 20 older (66.6 ± 4.2 years) adults participated in two experimental sessions involving either intermittent theta burst stimulation (iTBS) or sham stimulation over PMd. Changes within M1 following the intervention were assessed with motor‐evoked potentials (MEPs) recorded from the right first dorsal interosseous muscle. We applied posterior–anterior (PA) and anterior–posterior (AP) current single‐pulse TMS to assess corticospinal excitability (PA1mV; AP1mV; PA0.5mV, early; AP0.5mV, late), and paired‐pulse TMS short intracortical facilitation for I‐wave excitability (PA SICF, early; AP SICF, late). Although PMd iTBS potentiated PA1mV and AP1mV MEPs in both age groups (both P < 0.05), the time course of this effect was delayed for AP1mV in older adults (P = 0.001). Furthermore, while AP0.5mV, PA SICF and AP SICF were potentiated in both groups (all P < 0.05), potentiation of PA0.5mV was only apparent in young adults (P < 0.0001). While PMd influences early and late I‐wave excitability in young adults, direct PMd modulation of the early circuits is specifically reduced in older adults. Key points Interneuronal circuits responsible for late I‐waves within primary motor cortex (M1) mediate projections from dorsal premotor cortex (PMd), but this communication probably changes with advancing age. We investigated the effects of intermittent theta burst stimulation (iTBS) to PMd on transcranial magnetic stimulation (TMS) measures of M1 excitability in young and older adults. We found that PMd iTBS facilitated M1 excitability assessed with posterior–anterior (PA, early I‐waves) and anterior–posterior (AP, late I‐waves) current TMS in young adults, with a stronger effect for AP TMS. M1 excitability assessed with AP TMS also increased in older adults following PMd iTBS, but there was no facilitation for PA TMS responses. We conclude that changes in M1 excitability following PMd iTBS are specifically reduced for the early I‐waves in older adults, which could be a potential target for interventions that enhance cortical excitability in older adults.

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Cerebellar transcranial direct current stimulation disrupts neuroplasticity of intracortical motor circuits

Cited by 8 publications

References 59 publications

Effect of current direction and muscle activation on motor cortex neuroplasticity induced by repetitive paired‐pulse transcranial magnetic stimulation

Effect of current direction and muscle activation on motor cortex neuroplasticity induced by repetitive paired‐pulse transcranial magnetic stimulation

Investigating the effects of repetitive paired-pulse transcranial magnetic stimulation on visuomotor training using TMS-EEG

Modulation of dorsal premotor cortex differentially influences I‐wave excitability in primary motor cortex of young and older adults

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