Myoinositol content in the human brain is modified by transcranial direct current stimulation in a matter of minutes : a 1H-MRS study.

Brain content of myoinositol (mI) has been shown to be altered in several neuropsychiatric conditions. Likewise, various forms of electric currents have been applied to the human brain for therapeutic purposes in neuropsychiatric diseases. In this study we aimed to depict the effects of low-power transcranial direct current stimulation (tDCS) on brain mI by proton magnetic resonance spectroscopy (1H-MRS). We studied two groups of five healthy subjects by 1H-MRS: the first group was studied before and after both anodal and sham (placebo) tDCS over the right frontal lobe, and the second group was studied at the same intervals without undergoing either sham or anodal tDCS. Anodal tDCS induced a significant increase of mI content at 30 min after stimulation offset (141.5 ± 16.7%, P < 0.001) below the stimulating electrode but not in distant regions, such as the visual cortex, whereas sham tDCS failed to induce changes in mI. Neither N-acetyl-aspartate (NAA) nor the other metabolite contents changed after anodal or sham stimulation. 1H-MRS represents a powerful tool to follow the regional effects of tDCS on brain mI and, possibly, on the related phosphoinositide system.