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

• Published in: Brain stimulation Vol. 14; no. 1; pp. 154 - 160
• Main Authors: Bunai, Tomoyasu, Hirosawa, Tetsu, Kikuchi, Mitsuru, Fukai, Mina, Yokokura, Masamichi, Ito, Shigeru, Takata, Yohei, Terada, Tatsuhiro, Ouchi, Yasuomi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2021; Elsevier
• Subjects: Dopamine; Magnetic resonance spectroscopy; Positron emission topography; Transcranial direct current stimulation; γ-aminobutyric acid; Magnetic resonance spectroscopy; Positron emission topography; Dopamine; Transcranial direct current stimulation; γ-aminobutyric acid
• ISSN: 1935-861X; 1876-4754
• DOI: 10.1016/j.brs.2020.12.010

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