No trace of phase: Corticomotor excitability is not tuned by phase of pericentral mu-rhythm

Kristoffer Hougaard Madsen*, Anke Ninija Karabanov, Lærke Gebser Krohne, Mads Gylling Safeldt, Leo Tomasevic, Hartwig Roman Siebner

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Background: The motor potentials evoked by transcranial magnetic stimulation (TMS) over the motor hand area (M1-HAND) show substantial inter-trial variability. Pericentral mu-rhythm oscillations, might contribute to inter-trial variability. Recent studies targeting mu-activity based on real-time electroencephalography (EEG) reported an influence of mu-power and mu-phase on the amplitude of motor evoked potentials (MEPs) in a preselected group with strong pericentral mu-activity. Other studies that determined mu-power or mu-phase based on post-hoc trial sorting according in non-preselected individuals were largely negative.
Objectives: To reassess if cortico-spinal activity is modulated by the mu-rhythm, we applied single-pulse TMS to the M1-HAND conditional on the phase of the intrinsically expressed pericentral mu-rhythm in 14 non-preselected healthy young participants.
Methods: TMS was given at 0, 90, 180, and 270 of the mu-phase. Based on the absence of effects of muphase or mu-power when analyzing the mean MEP amplitudes, we also computed a linear mixed effects model, which included mu-phase, mu-power, inter-stimulus interval (ISIs) as fixed effects, treating the subject factor as a random effect.
Results: Mixed model analysis revealed a significant effect of mu-power and ISI, but no effect of muphase and no interactions. MEP amplitude scaled linearly with lower mu-power or longer ISIs, but these modulatory effects were very small relative to inter-trial MEP variability. Conclusion: Our largely negative results are in agreement with previous offline TMS-EEG studies and point to a possible influence of ISI. Future research needs to clarify under which circumstances the responsiveness of human the M1-HAND to TMS depends on the synchronicity with mu-power and muphase.
Original languageEnglish
JournalBrain Stimulation
Volume12
Issue number5
Pages (from-to)1261-1270
Number of pages10
ISSN1935-861X
DOIs
Publication statusPublished - 2019

Keywords

  • Electroencephalography
  • EEG-Triggered phase targeting
  • Mu rhythm
  • Pericentral oscillation
  • Temporal and spatial neuronavigation
  • Transcranial magnetic stimulation

Cite this

Madsen, Kristoffer Hougaard ; Karabanov, Anke Ninija ; Krohne, Lærke Gebser ; Gylling Safeldt, Mads ; Tomasevic, Leo ; Siebner, Hartwig Roman. / No trace of phase: Corticomotor excitability is not tuned by phase of pericentral mu-rhythm. In: Brain Stimulation. 2019 ; Vol. 12, No. 5. pp. 1261-1270.
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abstract = "Background: The motor potentials evoked by transcranial magnetic stimulation (TMS) over the motor hand area (M1-HAND) show substantial inter-trial variability. Pericentral mu-rhythm oscillations, might contribute to inter-trial variability. Recent studies targeting mu-activity based on real-time electroencephalography (EEG) reported an influence of mu-power and mu-phase on the amplitude of motor evoked potentials (MEPs) in a preselected group with strong pericentral mu-activity. Other studies that determined mu-power or mu-phase based on post-hoc trial sorting according in non-preselected individuals were largely negative.Objectives: To reassess if cortico-spinal activity is modulated by the mu-rhythm, we applied single-pulse TMS to the M1-HAND conditional on the phase of the intrinsically expressed pericentral mu-rhythm in 14 non-preselected healthy young participants.Methods: TMS was given at 0, 90, 180, and 270 of the mu-phase. Based on the absence of effects of muphase or mu-power when analyzing the mean MEP amplitudes, we also computed a linear mixed effects model, which included mu-phase, mu-power, inter-stimulus interval (ISIs) as fixed effects, treating the subject factor as a random effect.Results: Mixed model analysis revealed a significant effect of mu-power and ISI, but no effect of muphase and no interactions. MEP amplitude scaled linearly with lower mu-power or longer ISIs, but these modulatory effects were very small relative to inter-trial MEP variability. Conclusion: Our largely negative results are in agreement with previous offline TMS-EEG studies and point to a possible influence of ISI. Future research needs to clarify under which circumstances the responsiveness of human the M1-HAND to TMS depends on the synchronicity with mu-power and muphase.",
keywords = "Electroencephalography, EEG-Triggered phase targeting, Mu rhythm, Pericentral oscillation, Temporal and spatial neuronavigation, Transcranial magnetic stimulation",
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No trace of phase: Corticomotor excitability is not tuned by phase of pericentral mu-rhythm. / Madsen, Kristoffer Hougaard; Karabanov, Anke Ninija; Krohne, Lærke Gebser; Gylling Safeldt, Mads; Tomasevic, Leo; Siebner, Hartwig Roman.

In: Brain Stimulation, Vol. 12, No. 5, 2019, p. 1261-1270.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - No trace of phase: Corticomotor excitability is not tuned by phase of pericentral mu-rhythm

AU - Madsen, Kristoffer Hougaard

AU - Karabanov, Anke Ninija

AU - Krohne, Lærke Gebser

AU - Gylling Safeldt, Mads

AU - Tomasevic, Leo

AU - Siebner, Hartwig Roman

PY - 2019

Y1 - 2019

N2 - Background: The motor potentials evoked by transcranial magnetic stimulation (TMS) over the motor hand area (M1-HAND) show substantial inter-trial variability. Pericentral mu-rhythm oscillations, might contribute to inter-trial variability. Recent studies targeting mu-activity based on real-time electroencephalography (EEG) reported an influence of mu-power and mu-phase on the amplitude of motor evoked potentials (MEPs) in a preselected group with strong pericentral mu-activity. Other studies that determined mu-power or mu-phase based on post-hoc trial sorting according in non-preselected individuals were largely negative.Objectives: To reassess if cortico-spinal activity is modulated by the mu-rhythm, we applied single-pulse TMS to the M1-HAND conditional on the phase of the intrinsically expressed pericentral mu-rhythm in 14 non-preselected healthy young participants.Methods: TMS was given at 0, 90, 180, and 270 of the mu-phase. Based on the absence of effects of muphase or mu-power when analyzing the mean MEP amplitudes, we also computed a linear mixed effects model, which included mu-phase, mu-power, inter-stimulus interval (ISIs) as fixed effects, treating the subject factor as a random effect.Results: Mixed model analysis revealed a significant effect of mu-power and ISI, but no effect of muphase and no interactions. MEP amplitude scaled linearly with lower mu-power or longer ISIs, but these modulatory effects were very small relative to inter-trial MEP variability. Conclusion: Our largely negative results are in agreement with previous offline TMS-EEG studies and point to a possible influence of ISI. Future research needs to clarify under which circumstances the responsiveness of human the M1-HAND to TMS depends on the synchronicity with mu-power and muphase.

AB - Background: The motor potentials evoked by transcranial magnetic stimulation (TMS) over the motor hand area (M1-HAND) show substantial inter-trial variability. Pericentral mu-rhythm oscillations, might contribute to inter-trial variability. Recent studies targeting mu-activity based on real-time electroencephalography (EEG) reported an influence of mu-power and mu-phase on the amplitude of motor evoked potentials (MEPs) in a preselected group with strong pericentral mu-activity. Other studies that determined mu-power or mu-phase based on post-hoc trial sorting according in non-preselected individuals were largely negative.Objectives: To reassess if cortico-spinal activity is modulated by the mu-rhythm, we applied single-pulse TMS to the M1-HAND conditional on the phase of the intrinsically expressed pericentral mu-rhythm in 14 non-preselected healthy young participants.Methods: TMS was given at 0, 90, 180, and 270 of the mu-phase. Based on the absence of effects of muphase or mu-power when analyzing the mean MEP amplitudes, we also computed a linear mixed effects model, which included mu-phase, mu-power, inter-stimulus interval (ISIs) as fixed effects, treating the subject factor as a random effect.Results: Mixed model analysis revealed a significant effect of mu-power and ISI, but no effect of muphase and no interactions. MEP amplitude scaled linearly with lower mu-power or longer ISIs, but these modulatory effects were very small relative to inter-trial MEP variability. Conclusion: Our largely negative results are in agreement with previous offline TMS-EEG studies and point to a possible influence of ISI. Future research needs to clarify under which circumstances the responsiveness of human the M1-HAND to TMS depends on the synchronicity with mu-power and muphase.

KW - Electroencephalography

KW - EEG-Triggered phase targeting

KW - Mu rhythm

KW - Pericentral oscillation

KW - Temporal and spatial neuronavigation

KW - Transcranial magnetic stimulation

U2 - 10.1016/j.brs.2019.05.005

DO - 10.1016/j.brs.2019.05.005

M3 - Journal article

C2 - 31133479

VL - 12

SP - 1261

EP - 1270

JO - Brain Stimulation

JF - Brain Stimulation

SN - 1935-861X

IS - 5

ER -