Effects of anodal- tDCS on implicit motor learning and language-related brain function: An fMRI study.
AIM: Anodal transcranial Direct Current Stimulation (tDCS) over the left dorsolateral prefrontal cortex (DLPFC) is known as one of the useful applications for improving depressive symptoms or cognitive performance. Antidepressive effects by anodal tDCS over the left DLPFC are expected, but the neural mechanisms of these effects are still unclear. Further, in depression, reduced performance and left prefrontal hypofunction during verbal fluency task (VFT) are generally known. However, few studies have examined the effect of tDCS on the language-related cerebral network. We aimed to investigate whether anodal tDCS at the left DLPFC affects cognitive performance and the neural basis of verbal fluency.
METHODS: Nineteen healthy volunteers participated in this study. The effects of tDCS on cognitive behavior and cerebral function were evaluated by 1) performance and accuracy of implicit/explicit motor learning task (serial reaction time task: SRTT/sequential finger-tapping task: SFTT), and 2) cerebral activation while the subjects were performing VFT by using a functional MRI protocol of a randomized sham-controlled, within-subjects cross-over design.
RESULTS: Reaction times of implicit motor learning task were significantly faster by tDCS in comparison with sham. Further, language-related left prefrontal-parahippocampal-parietal activation was significantly less by tDCS compared with sham. Significant correlation was observed between shortened response time in SRTT and decreased cerebral activation during VFT by tDCS.
CONCLUSION: Anodal tDCS over the left DLPFC could improve cognitive behavior of implicit motor learning by improving brain function of the frontoparietal-parahippocampal region related to motor learning, as well as language-related regions. This article is protected by copyright. All rights reserved.
PMID: 33576537 [PubMed – as supplied by publisher]
Psychiatry Clin Neurosci. 2021 Feb 12;:
Authors: Nakashima S, Koeda M, Ikeda Y, Hama T, Funayama T, Akiyama T, Arakawa R, Tateno A, Suzuki H, Okubo Y