Bilateral Transcranial Direct Current Stimulation Modulates Activation-Induced Regional Blood Flow Changes during Voluntary Movement

• Published in: Journal of cerebral blood flow and metabolism Vol. 31; no. 10; pp. 2086 - 2095
• Main Authors: Paquette, Caroline, Sidel, Michael, Radinska, Basia A, Soucy, Jean-Paul, Thiel, Alexander
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.10.2011; Nature Publishing Group; Sage Publications Ltd
• Subjects: Adolescent; Adult; Biological and medical sciences; Blood Flow Velocity; Cerebrovascular Circulation; Electric Stimulation; Female; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Motor Cortex - blood supply; Movement; Nervous system; Neurology; Neurons - metabolism; Original; Positron-Emission Tomography; Ultrasonic investigative techniques; Vascular diseases and vascular malformations of the nervous system; positron emission tomography; finger movements; human motor cortex; transcranial direct current stimulation; motor evoked potentials; Human; Regional blood flow; Nervous system diseases; Finger; Cerebral disorder; Direct current; Motor cortex; Central nervous system disease; Motor evoked potential; Positron emission tomography; Cerebrovascular disease; Emission tomography
• ISSN: 0271-678X; 1559-7016; 1559-7016
• DOI: 10.1038/jcbfm.2011.72

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that induces changes in cortical excitability: anodal stimulation increases while cathodal stimulation reduces excitability. Imaging studies performed after unilateral stimulation have shown conflicting results regarding the effects of tDCS on surrogate markers of neuronal activity. The aim of this study was to directly measure these effects on activation-induced changes in regional cerebral blood flow (⊿rBF) using positron emission tomography (PET) during bilateral tDCS. Nine healthy subjects underwent repeated rCBF measurements with 15O-water and PET during a simple motor task while receiving tDCS or sham stimulation over the primary motor cortex (M1). Motor evoked potentials (MEPs) were also assessed before and after real and sham stimulation. During tDCS with active movement, ⊿rBF in M1 was significantly lower on the cathodal than the anodal side when compared with sham stimulation. This decrease in ⊿rBF was accompanied by a decrease in MEP amplitude on the cathodal side. No effect was observed on resting or activated rCBF relative to sham stimulation. We thus conclude that it is the interaction of cathodal tDCS with activation-induced ⊿rBF rather than the effect on resting or activated rCBF itself which constitutes the physiological imaging correlate of tDCS.