tDCS-induced modulation of GABA concentration and dopamine release in the human brain: A combination study of magnetic resonance spectroscopy and positron emission tomography

BackgroundTranscranial direct current stimulation (tDCS) to the dorsolateral prefrontal cortex (DLPFC) hypothetically modulates cognitive functions by facilitating or inhibiting neuronal activities chiefly in cerebral cortex. The effect of tDCS deeper brain region, basal ganglia-cortical circuit, remains unknown.ObjectiveTo investigate interaction between ?-aminobutyric acid (GABA) concentrations and dopamine release following tDCS.MethodThis study used a randomized, placebo-controlled, double-blind, crossover design. Seventeen healthy male subjects underwent active sham (13 min twice at an interval 20 min) with anode placed left DLPFC cathode right DLPFC, followed examinations [11C]-raclopride positron emission topography (PET) GABA-magnetic resonance spectroscopy (MRS). MRS voxels were set bilateral striata. Paired t-tests regression analyses performed for PET parameters.ResultsMRS data showed elevations GABA striatum along moderate reductions after tDCS. that binding potentials (increase release) inversely correlated those positively increases striatal negatively release.ConclusionThe present results suggest dopamine-GABA circuit.