Assessing cortical synchronization during transcranial direct current stimulation: A graph-theoretical analysis

Matteo Mancini, Debora Brignani, Silvia Conforto, Piercarlo Mauri, Carlo Miniussi, Maria Concetta Pellicciari

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Transcranial direct current stimulation (tDCS) is a neuromodulation technique that can alter cortical excitability and modulate behaviour in a polarity-dependent way. Despite the widespread use of this method in the neuroscience field, its effects on ongoing local or global (network level) neuronal activity are still not foreseeable. A way to shed light on the neuronal mechanisms underlying the cortical connectivity changes induced by tDCS is provided by the combination of tDCS with electroencephalography (EEG). In this study, twelve healthy subjects underwent online tDCS-EEG recording (i.e., simultaneous), during resting-state, using 19 EEG channels. The protocol involved anodal, cathodal and sham stimulation conditions, with the active and the reference electrodes in the left frontocentral area (FC3) and on the forehead over the right eyebrow, respectively. The data were processed using a network model, based on graph theory and the synchronization likelihood. The resulting graphs were analysed for four frequency bands (theta, alpha, beta and gamma) to evaluate the presence of tDCS-induced differences in synchronization patterns and graph theory measures. The resting state network connectivity resulted altered during tDCS, in a polarity-specific manner for theta and alpha bands. Anodal tDCS weakened synchronization with respect to the baseline over the fronto-central areas in the left hemisphere, for theta band (p < 0.05). In contrast, during cathodal tDCS a significant increase in inter-hemispheric synchronization connectivity was observed over the centro-parietal, centro-occipital and parieto-occipital areas for the alpha band (p < 0.05). Local graph measures showed a tDCS-induced polarity-specific differences that regarded modifications of network activities rather than specific region properties. Our results show that applying tDCS during the resting state modulates local synchronization as well as network properties in slow frequency bands, in a polarity-specific manner.

Original languageEnglish
Pages (from-to)57-65
Number of pages9
JournalNeuroImage
Volume140
DOIs
Publication statusPublished - Oct 15 2016

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Cortical Synchronization
Electroencephalography
Transcranial Direct Current Stimulation
Eyebrows
Forehead
Neurosciences
Healthy Volunteers
Electrodes

Keywords

  • Cortical activity
  • EEG
  • Functional connectivity
  • Graph theory
  • Synchronization likelihood
  • tDCS

ASJC Scopus subject areas

  • Neurology
  • Cognitive Neuroscience

Cite this

Assessing cortical synchronization during transcranial direct current stimulation : A graph-theoretical analysis. / Mancini, Matteo; Brignani, Debora; Conforto, Silvia; Mauri, Piercarlo; Miniussi, Carlo; Pellicciari, Maria Concetta.

In: NeuroImage, Vol. 140, 15.10.2016, p. 57-65.

Research output: Contribution to journalArticle

Mancini, Matteo ; Brignani, Debora ; Conforto, Silvia ; Mauri, Piercarlo ; Miniussi, Carlo ; Pellicciari, Maria Concetta. / Assessing cortical synchronization during transcranial direct current stimulation : A graph-theoretical analysis. In: NeuroImage. 2016 ; Vol. 140. pp. 57-65.
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