Effects of transcranial electrical stimulation on primary visual cortex using resting-state fMRI
Poster No:
103
Submission Type:
Abstract Submission
Authors:
Yangling Zhou1, Rui Qian1, Chengjiaao Liao1, Huaijin Gao1, Zhiyong Zhao1, Minmin Wang1, Dan Wu1, Shaomin Zhang2
Institutions:
1Zhejiang University, Hangzhou, China, 2Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China
First Author:
Co-Author(s):
Introduction:
Transcranial direct current stimulation (tDCS) has been demonstrated to be effective in the treatment of neurological and psychiatric diseases by regulating neural activities[1]. Recent evidence shows that human primary visual cortex (V1) plays a vital role in neurocognitive function[2,3] , however, the impact of tDCS on the V1 remains unclear. Therefore, this study aims to investigate the effect of tDCS on V1 using resting-state functional magnetic resonance imaging (rs-fMRI).
Methods:
The study included 10 healthy adults (6 males, age 22.8±1.9 years) and received approval from the IRB. Participants underwent 15 days of stimulation and a two-week follow-up. In the stimulation period, each participant received 2mA anodal tDCS for 20 minutes, targeting V1 (stimulation montage: PO3, 2 mA; FT7, -0.6 mA; CZ, -0.5 mA; Iz, -0.9 mA) with Molecular Neurological Institute coordinates (x, y, z) = (6, -63, 15) (Figure 1a), who experienced three sessions in which each one of them included MRI scanning before, during and after stimulation, respectively. In the follow-up, MRI data were collected on the 8th and 15th day respectively. The pipeline of the entire experiment is shown in Figure 1b.
All MRI data were acquired on a 3.0T Siemens Prisma scanner .The rs-fMRI data were preprocessed using DPABI[4], including slice timing correction, realignment, normalization, smoothing, and filtering (0.01–0.1 Hz), and then fractional amplitude of low-frequency fluctuation[5] (fALFF) and functional connectivity [6](FC) were calculated for each participant. Paired t-tests were conducted on fALFF and FC before and after each stimulation to explore the short-term effect of tDCS, and between the 8th, 15th, 22nd as well as 29th day and the baseline (the 1st day) to explore the long-term effects of tDCS (Figure 1b). Gaussian Random Field (GRF) theory was used to perform multiple comparison corrections on the results of the paired t-tests, with a voxel threshold of p < 0.01 and a cluster threshold of p < 0.05.
All MRI data were acquired on a 3.0T Siemens Prisma scanner .The rs-fMRI data were preprocessed using DPABI[4], including slice timing correction, realignment, normalization, smoothing, and filtering (0.01–0.1 Hz), and then fractional amplitude of low-frequency fluctuation[5] (fALFF) and functional connectivity [6](FC) were calculated for each participant. Paired t-tests were conducted on fALFF and FC before and after each stimulation to explore the short-term effect of tDCS, and between the 8th, 15th, 22nd as well as 29th day and the baseline (the 1st day) to explore the long-term effects of tDCS (Figure 1b). Gaussian Random Field (GRF) theory was used to perform multiple comparison corrections on the results of the paired t-tests, with a voxel threshold of p < 0.01 and a cluster threshold of p < 0.05.
Results:
The tDCS on V1 increased fALFF values in the bilateral superior frontal gyrus, middle frontal gyrus, and posterior cerebellar lobes during three short-term stimulations (Figure 1c). Long-term stimulation showed increased activity in the frontal regions on the 8th day and decreased activity in the superior parietal lobe and precuneus on the 8th and 15th day, while the occipital lobe and posterior cerebellum exhibited increased activity on the 22nd and 29th day after stimulation (Figure 1d).
FC analysis revealed two recurring brain states, in which State 1 exhibited strong connectivity between the medial frontal lobe as well as posterior cingulate gyrus (default mode network, DMN) and the V1, and State 2 showed a common strong connectivity in widespread regions with the V1(Figure 2a). During 20-mintue stimulation, State 1 occurred more frequently than State 2(Figure 2b-c), and transitions from State 2 to State 1 were predominant (Figure 2d).
FC analysis revealed two recurring brain states, in which State 1 exhibited strong connectivity between the medial frontal lobe as well as posterior cingulate gyrus (default mode network, DMN) and the V1, and State 2 showed a common strong connectivity in widespread regions with the V1(Figure 2a). During 20-mintue stimulation, State 1 occurred more frequently than State 2(Figure 2b-c), and transitions from State 2 to State 1 were predominant (Figure 2d).
Conclusions:
This study explored the effects of tDCS targeting V1 on resting-state brain activity. The increased fALFF in the frontal and cerebellar regions after short- and long-term stimulations suggests that electrical stimulation may exert a regulatory influence on cognitive functions [7]. The FC-based state analysis found that the brain preferred to stay in the state with strong connectivity between DMN and V1 during the stimulation. This suggests that tDCS may regulate emotional and cognitive functions [8] by modulating the DMN. Additionally, the cerebellum was significantly activated by tDCS, which was implicated in cognitive and psychological activity [9,10]. In summary, these findings contribute to the understanding of the mechanisms of tDCS on V1 and its potential for non-invasive interventions in neurological disorders and cognitive enhancement.
·Figure 1. Method diagram & fALFF results. The red and blue in color bar represent increased and decreased fALFF value compared to baseline (GRF correction, voxel-wise p < 0.01, cluster-wise p < 0.05).
·Figure 2. Analysis of Dynamic functional connection state. State 1 and 2 exhibited strong connectivity in default mode network and in widespread cortical regions with the V1, respectively.
Brain Stimulation:
TDCS 1
Modeling and Analysis Methods:
Connectivity (eg. functional, effective, structural)
fMRI Connectivity and Network Modeling
Novel Imaging Acquisition Methods:
BOLD fMRI 2
Keywords:
Design and Analysis
FUNCTIONAL MRI
Other - tDCS
1|2Indicates the priority used for review
Provide references using author date format
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