Background: Brain responses to external stimuli vary with fluctuating states of neuronal activity. Previous work has demonstrated effects of phase and power of the ongoing local sensorimotor μ-alpha-oscillation on responses to transcranial magnetic stimulation (TMS) of motor cortex (M1). However, M1 is part of a distributed network, and the effects of oscillatory activity in this network on TMS-evoked EEG responses (TEPs) have not been explored. Objectives: To determine the effects of oscillatory activity in the bihemispheric sensorimotor network on TEPs. Methods: 31 healthy subjects received single-pulse TMS of the left M1 hand area during EEG recording. Ongoing bihemispheric sensorimotor cortex oscillatory states were reconstructed from the EEG directly preceding TMS, and inferred by a data-driven method combining a multivariate autoregressive model and a Hidden Markov model. TEP amplitudes (P25, N45, P70, N100 and P180) were then compared between different bihemispheric sensorimotor cortex oscillatory states. Results: Four bihemispheric sensorimotor cortex oscillatory states were identified, with different interhemispheric expressions of theta and alpha oscillations. High alpha-power states in the stimulated sensorimotor cortex increased P25 amplitude. Alpha power in the alpha-alpha state (stimulated - non-stimulated hemisphere) correlated in both hemispheres with N45 amplitude. Theta power in the alpha-theta state correlated in the non-stimulated hemisphere with P70 amplitude. Conclusions: Bihemispheric sensorimotor cortex oscillatory states contribute to TEPs, with a relevance shift from stimulated to non-stimulated M1 from P25 over N45 to P70. This significantly extends previous findings: not only ongoing local oscillations but distributed network oscillatory states determine cortical responsiveness to external stimuli.

Bihemispheric sensorimotor oscillatory network states determine cortical responses to transcranial magnetic stimulation / Bai, Y.; Belardinelli, P.; Ziemann, U.. - In: BRAIN STIMULATION. - ISSN 1935-861X. - ELETTRONICO. - 15:1(2022), pp. 167-178. [10.1016/j.brs.2021.12.002]

Bihemispheric sensorimotor oscillatory network states determine cortical responses to transcranial magnetic stimulation

Belardinelli P.;
2022-01-01

Abstract

Background: Brain responses to external stimuli vary with fluctuating states of neuronal activity. Previous work has demonstrated effects of phase and power of the ongoing local sensorimotor μ-alpha-oscillation on responses to transcranial magnetic stimulation (TMS) of motor cortex (M1). However, M1 is part of a distributed network, and the effects of oscillatory activity in this network on TMS-evoked EEG responses (TEPs) have not been explored. Objectives: To determine the effects of oscillatory activity in the bihemispheric sensorimotor network on TEPs. Methods: 31 healthy subjects received single-pulse TMS of the left M1 hand area during EEG recording. Ongoing bihemispheric sensorimotor cortex oscillatory states were reconstructed from the EEG directly preceding TMS, and inferred by a data-driven method combining a multivariate autoregressive model and a Hidden Markov model. TEP amplitudes (P25, N45, P70, N100 and P180) were then compared between different bihemispheric sensorimotor cortex oscillatory states. Results: Four bihemispheric sensorimotor cortex oscillatory states were identified, with different interhemispheric expressions of theta and alpha oscillations. High alpha-power states in the stimulated sensorimotor cortex increased P25 amplitude. Alpha power in the alpha-alpha state (stimulated - non-stimulated hemisphere) correlated in both hemispheres with N45 amplitude. Theta power in the alpha-theta state correlated in the non-stimulated hemisphere with P70 amplitude. Conclusions: Bihemispheric sensorimotor cortex oscillatory states contribute to TEPs, with a relevance shift from stimulated to non-stimulated M1 from P25 over N45 to P70. This significantly extends previous findings: not only ongoing local oscillations but distributed network oscillatory states determine cortical responsiveness to external stimuli.
2022
1
Bai, Y.; Belardinelli, P.; Ziemann, U.
Bihemispheric sensorimotor oscillatory network states determine cortical responses to transcranial magnetic stimulation / Bai, Y.; Belardinelli, P.; Ziemann, U.. - In: BRAIN STIMULATION. - ISSN 1935-861X. - ELETTRONICO. - 15:1(2022), pp. 167-178. [10.1016/j.brs.2021.12.002]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/325578
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