The Effect of tDCS on EEG-Based Functional Connectivity in Gait Motor Imagery
Transcranial direct current stimulation (tDCS) is a non-invasive technique for brain stimulation capable of modulating brain excitability. Although beneficial effects of tDCS have been shown, the underlying brain mechanisms have not been described. In the present study, we aim to investigate the effects of tDCS on EEG-based functional connectivity, through a partial directed coherence (PDC) analysis, which is a frequency-domain metric that provides information about directionality in the interaction between signals recorded at different channels. The tDCS montage used in our study, was focused on the lower limbs and it was composed of two anodes and one cathode. A single-blind study was carried out, where eight healthy subjects were randomly separated into two groups: sham and active tDCS. Results showed that, for the active tDCS group, the central EEG electrodes Cz, C3 and C4 turned out to be highly connected within alpha and beta frequency bands. On the contrary, the sham group presented a tendency to be more random at its functional connections.
KeywordsPDC Functional connectivity Motor imagery BCI EEG Gait tDCS
This research has been carried out in the framework of the project Associate - Decoding and stimulation of motor and sensory brain activity to support long term potentiation through Hebbian and paired associative stimulation during rehabilitation of gait (DPI2014-58431-C4-2-R), funded by the Spanish Ministry of Economy and Competitiveness and by the European Union through the European Regional Development Fund (ERDF) “A way to build Europe”. Also, the Mexican Council of Science and Technology (CONACyT) provided J. A. Gaxiola-Tirado his scholarship, under Grant 220145.
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