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Updated: Apr 7, 2026
Transcranial Direct Current Stimulation and Simultaneous Functional Magnetic Resonance Imaging
Published on: April 27, 2014
Simultaneous tDCS-fMRI reveals limited and inconsistent changes in functional connectivity: Insights from a temporal
Debby C W Klooster1,2, Guo-Rong Wu3, Sara de Witte2,4,5
1Eindhoven University of Technology, Department of Electrical Engineering, Electromagnetics for Care and Cure, Flux Building, Eindhoven, The Netherlands.
Abstract:
Transcranial direct current stimulation (tDCS) is a non-invasive form of neuromodulation. Previous work has shown that tDCS affects functional connectivity, typically assessed by comparing resting-state functional MRI (rs-fMRI) data collected before and after the intervention. This study focuses on the temporal dynamics of functional connectivity during tDCS. Additionally, electric field simulations are incorporated in functional connectivity analyses to gain more insights into the mechanism of action. Forty-seven healthy female volunteers were enrolled in a randomized, sham-controlled, cross-over design in which sham and active tDCS were administered to the left dorsolateral prefrontal cortex for 20 min at 1.5 mA. Functional connectivity analyses were performed on rs-fMRI data collected before, during, and after tDCS, using three seed regions in the brain: one under the anode, one under the cathode, and one at the brain region where the individual tDCS-induced electric field strength was highest. The rs-fMRI data collected during stimulation were divided into three time windows to obtain temporal information on functional connectivity during stimulation. Functional connectivity was assessed at the whole-brain level using seed-to-voxel analyses as well as within predefined resting-state networks. TDCS did not consistently change functional connectivity over time. On the whole-brain level, active tDCS did not affect functional connectivity during stimulation. After active stimulation, only the functional connectivity between the cathode and the postcentral gyrus was increased. At the network level, changes in functional connectivity were observed following both sham and active tDCS, indicating that these effects could not be specifically attributed to active stimulation. Future research should further investigate the relationship between tDCS-induced effects on functional connectivity and their potential links to clinical responses.
