Selective Functional Network Changes Following tDCS-Augmented Language Treatment in Primary Progressive Aphasia

作者：Tao Yuan, Bronte Ficek, Zeyi Wang, Brenda Rapp, Kyrana Tsapkini · 发表于：Frontiers in Aging Neuroscience · 年份：2021 · DOI：10.3389/fnagi.2021.681043 · 被引用次数：34 · 研究领域：Transcranial Magnetic Stimulation Studies、Neurobiology of Language and Bilingualism、Action Observation and Synchronization

Objective Transcranial direct current stimulation (tDCS) has shown promising results when used as an adjunct to behavioral training in neurodegenerative diseases. However, the underlying neural mechanisms are not understood and neuroimaging evidence from pre/post treatment has been sparse. In this study, we examined tDCS-induced neural changes in a language intervention study for primary progressive aphasia (PPA), a neurodegenerative syndrome with language impairment as the primary clinical presentation. Anodal tDCS was applied to the left inferior frontal gyrus (LIFG). To evaluate the hypothesis that tDCS promotes system segregation, analysis focused on understanding tDCS-induced changes in the brain-wide functional network connectivity of the targeted LIFG. Methods Resting-state fMRI data were obtained from 32 participants with PPA before and after receiving a written naming therapy, accompanied either by tDCS or sham stimulation. We focused on evaluating changes in the global connectivity of the stimulated LIFG-triangularis (LIFG-tri) region given its important role in lexical processing. Global connectivity was indexed by the graph-theoretic measure participation coefficient (PC) which quantifies a region’s level of system segregation. The values before and after treatment were compared for each condition (tDCS or Sham) as well as with age-matched healthy controls ( n = 19). Results Higher global connectivity of the LIFG-tri before treatment was associated with greater de...