Journal article
Age-dependent effects of brain stimulation on network centrality
University of Greifswald1
Free University of Berlin2
University of Queensland3
Humboldt University of Berlin4
Department of Electrical Engineering, Technical University of Denmark5
Center for Magnetic Resonance, Department of Electrical Engineering, Technical University of Denmark6
Physikalisch-Technische Bundesanstalt7
Functional magnetic resonance imaging (fMRI) studies have suggested that advanced age may mediate the effects of transcranial direct current stimulation (tDCS) on brain function. However, studies directly comparing neural tDCS effects between young and older adults are scarce and limited to task-related imaging paradigms.
Resting-state (rs-) fMRI, that is independent of age-related differences in performance, is well suited to investigate age associated differential neural tDCS effects. Three “online” tDCS conditions (anodal, cathodal, sham) were compared in a cross-over, within-subject design, in 30 young and 30 older adults.
Active stimulation targeted the left sensorimotor network (active electrode over left sensorimotor cortex with right supraorbital reference electrode). A graph-based rs-fMRI data analysis approach (eigenvector centrality mapping) and complementary seed-based analyses characterized neural tDCS effects.
An interaction between anodal tDCS and age group was observed. Specifically, centrality in bilateral paracentral and posterior regions (precuneus, superior parietal cortex) was increased in young, but decreased in older adults. Seed-based analyses revealed that these opposing patterns of tDCS-induced centrality modulation were explained from differential effects of tDCS on functional coupling of the stimulated left paracentral lobule.
Cathodal tDCS did not show significant effects. Our study provides first evidence for differential tDCS effects on neural network organization in young and older adults. Anodal stimulation mainly affected coupling of sensorimotor with ventromedial prefrontal areas in young and decoupling with posteromedial areas in older adults.
Language: | English |
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Publisher: | Academic Press |
Year: | 2018 |
Pages: | 71-82 |
ISSN: | 10959572 and 10538119 |
Types: | Journal article |
DOI: | 10.1016/j.neuroimage.2018.04.038 |
ORCIDs: | Thielscher, Axel |