Phase‐dependent local brain states determine the impact of image‐guided transcranial magnetic stimulation on motor network electroencephalographic synchronization
Abstract
Recent studies have synchronized transcranial magnetic stimulation (TMS) application with pre‐defined brain oscillatory phases showing how brain response to perturbation depends on the brain state. However, none have investigated whether phase‐dependent TMS can possibly modulate connectivity with homologous distant brain regions belonging to the same network. In the framework of network‐targeted TMS, we investigated whether stimulation delivered at a specific phase of ongoing brain oscillations might favour stronger cortico‐cortical (c‐c) synchronization of distant network nodes connected to the stimulation target. Neuronavigated TMS pulses were delivered over the primary motor cortex (M1) during ongoing electroencephalography recording in 24 healthy individuals over two repeated sessions 1 month apart. Stimulation effects were analysed considering whether the TMS pulse was delivered at the time of a positive (peak) or negative (trough) phase of μ‐frequency oscillation, which determines c‐c synchrony within homologous areas of the sensorimotor network. Diffusion weighted imaging was used to study c‐c connectivity within the sensorimotor network and identify contralateral regions connected with the stimulation spot. Depending on when during the μ‐activity the TMS‐pulse was applied (peak or trough), its impact on inter‐hemispheric network synchrony varied significantly. Higher M1–M1 phase‐lock synchronization after the TMS‐pulse (0–200 ms) in the μ‐frequency band was found for trough compared to peak stimulation trials in both study visits. Phase‐dependent TMS delivery might be crucial not only to amplify local effects but also to increase the magnitude and reliability of the response to the external perturbation, with implications for interventions aimed at engaging more distributed functional brain networks.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 09, 2022
- Source ID
- 10.1113/jp282393
Entities
People
- Alberto Di Domenico
- Alvaro Pascual‐leone
- Davide Momi
- Ehsan Tadayon
- Emiliano Santarnecchi
- Mirco Fasolo
- Mouhsin M. Shafi
- Pierre Boucher
- Recep A. Ozdemir
Organizations
- Alzheimer's Drug Discovery Foundation
- Autonomous University of Barcelona
- Beth Israel Deaconess Medical Center
- D'Annunzio University of Chieti–Pescara
- Defense Advanced Research Projects Agency
- Harvard Medical School
- Hebrew SeniorLife
- National Institutes of Health