Prefrontal Transcranial Direct Current Stimulation Changes Connectivity of Resting-State Networks during fMRI

Abstract

Transcranial direct current stimulation (tDCS) has been proposed for experimental and therapeutic modulation of regional brain function. Specifically, anodal tDCS of the dorsolateral prefrontal cortex (DLPFC) together with cathodal tDCS of the supraorbital region have been associated with improvement of cognition and mood, and have been suggested for the treatment of several neurological and psychiatric disorders. Although modeled mathematically, the distribution, direction, and extent of tDCSmediated effects on brain physiology are not well understood. The current study investigates whether tDCS of the human prefrontal cortex modulates resting-state network (RSN) connectivity measured by functional magnetic resonance imaging (fMRI). Thirteen healthy subjects underwent real and sham tDCS in random order on separate days. tDCS was applied for 20 min at 2 mA with the anode positioned over the left DLPFC and the cathode over the right supraorbital region. Patterns of resting-state brain connectivity were assessed before and after tDCS with 3 T fMRI, and changes were analyzed for relevant networks related to the stimulation-electrode localizations. At baseline, four RSNs were detected, corresponding to the default mode network (DMN), the left and right frontal-parietal networks (FPNs) and the self-referential network. After real tDCS and compared with sham tDCS, significant changes of regional brain connectivity were found for the DMN and the FPNs both close to the primary stimulation site and in connected brain regions. These findings show that prefrontal tDCS modulates resting-state functional connectivity in distinct functional networks of the human brain.

Imaging human brain networks to improve the clinical efficacy of non-invasive brain stimulation

“…When the left DLPFC was stimulated with anodal tDCS, and the right supraorbital region received cathodal tDCS, resting-state fMRI showed changes in connectivity within both the default-mode network and fronto-parietal networks (Keeser et al, 2011). A c c e p t e d M a n u s c r i p t Sale et al,21 5.…”

Transcranial electric stimulation and neurocognitive training in clinically depressed patients: A pilot study of the effects on rumination

“…This biological technique induces small changes (<1mV) in the membrane potential (Datta et al, 2009), acting in the frequency of spike timing and modifying net cortical excitability (Purpura & McMurtry, 1965), which can increase cortical perfusion and functional activity (Keeser et al, 2011). Anodal stimulation is found to increase cortical excitability, whereas cathodal stimulation is found to decrease excitability.…”

La stimulation transcrânienne à courant continu : un nouvel outil de neurostimulation

“…Une ré cente é tude de neuroimagerie a mis en é vidence l'effet d'une stimulation pré frontale sur la connectivité neuronale grâ ce à l'IRMf. Cette technique a montré une modulation de la connectivité du ré seau du mode par dé faut et des ré seaux fronto-parié taux bilaté ralement à la suite d'une stimulation du cortex PFDL gauche (Keeser et al, 2011). Cette é tude met en é vidence les mé canismes sous-jacents de la tDCS qui pourraient expliquer, en partie, les effets cognitifs de la stimulation.…”