Journal Article

Repeated anodal high-definition transcranial direct current stimulation over the left dorsolateral prefrontal cortex in mild cognitive impairment patients increased regional homogeneity in multiple brain regions

Li, Chenxi, He, Fangmei, Li, Youjun, Fan, Liming, Wang, Jue, Liu, Tian

2021

Overview

Transcranial direct current stimulation (tDCS) can improve cognitive function. However, it is not clear how high-definition tDCS (HD-tDCS) regulates the cognitive function and its neural mechanism, especially in individuals with mild cognitive impairment (MCI). This study aimed to examine whether HD-tDCS can modulate cognitive function in individuals with MCI and to determine whether the potential variety is related to spontaneous brain activity changes recorded by resting-state functional magnetic resonance imaging (rs-fMRI). Forty-three individuals with MCI were randomly assigned to receive either 10 HD-tDCS sessions or 10 sham sessions to the left dorsolateral prefrontal cortex (L-DLPFC). The fractional amplitude of low-frequency fluctuation (fALFF) and the regional homogeneity (ReHo) was computed using rs-fMRI data from all participants. The results showed that the fALFF and ReHo values changed in multiple areas following HD-tDCS. Brain regions with significant decreases in fALFF values include the Insula R, Precuneus R, Thalamus L, and Parietal Sup R, while the Temporal Inf R, Fusiform L, Occipital Sup L, Calcarine R, and Angular R showed significantly increased in their fALFF values. The brain regions with significant increases in ReHo values include the Temporal Inf R, Putamen L, Frontal Mid L, Precentral R, Frontal Sup Medial L, Frontal Sup R, and Precentral L. We found that HD-tDCS can alter the intensity and synchrony of brain activity, and our results indicate that fALFF and ReHo analysis are sensitive indicators for the detection of HD-tDCS during spontaneous brain activity. Interestingly, HD-tDCS increases the ReHo values of multiple brain regions, which may be related to the underlying mechanism of its clinical effects, these may also be related to a potential compensation mechanism involving the mobilization of more regions to complete a function following a functional decline.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Aged / Aged, 80 and over / Alzheimer's disease / Analysis / Biology and Life Sciences / Brain / Brain - diagnostic imaging / Brain - physiology / Brain mapping / Brain Mapping - methods / Brain research / Brain stimulation / Cognition / Cognition - physiology / Cognitive ability / Cognitive Dysfunction - diagnostic imaging / Cognitive Dysfunction - pathology / Cognitive Dysfunction - therapy / Complications and side effects / Cortex (frontal) / Cortex (occipital) / Cortex (parietal) / Cortex (temporal) / Dementia / Direct current / Dorsolateral Prefrontal Cortex - diagnostic imaging / Dorsolateral Prefrontal Cortex - physiology / Education / Electrical stimulation of the brain / Electrodes / Engineering research / ESB / Evaluation / Female / Functional magnetic resonance imaging / High definition / Homogeneity / Humans / Impairment / Informatics / Laboratories / Life sciences / Magnetic resonance / Magnetic resonance imaging / Magnetic Resonance Imaging - methods / Male / Medicine and Health Sciences / Memory / Middle Aged / Neuroimaging / Older people / Prefrontal cortex / Putamen / Rehabilitation / Research and Analysis Methods / Software / Stimulation / Temporal lobe / Thalamus / Transcranial Direct Current Stimulation - methods / Transcranial magnetic stimulation