Convergent and divergent structural and functional brain abnormalities associated with developmental dyslexia: a cross-linguistic meta-analysis of neuroimaging studies

Abstract

Brain abnormalities in the reading network have been repeatedly reported in individuals with developmental dyslexia (DD); however, it is still not totally understood where and why the structural and functional abnormalities are consistent/inconsistent across languages. In the current multimodal meta-analysis, we found convergent structural and functional alterations in the left superior temporal gyrus across languages, suggesting a neural signature of DD. We found greater reduction in grey matter volume and brain activation in the left inferior frontal gyrus in morpho-syllabic languages (e.g. Chinese) than in alphabetic languages, and greater reduction in brain activation in the left middle temporal gyrus and fusiform gyrus in alphabetic languages than in morpho-syllabic languages. These language differences are explained as consequences of being DD while learning a specific language. In addition, we also found brain regions that showed increased grey matter volume and brain activation, presumably suggesting compensations and brain regions that showed inconsistent alterations in brain structure and function. Our study provides important insights about the etiology of DD from a cross-linguistic perspective with considerations of consistency/inconsistency between structural and functional alterations.

Semantic processing during continuous speech production: an analysis from eye movements and EEG

“…It is well-documented that the frontal lobes are strongly associated with attention ( Corbetta and Shulman, 2002 ; Doricchi et al, 2010 ), working memory ( du Boisgueheneuc et al, 2006 ), dyslexia ( Vasic et al, 2008 ), and other linguistic cognitive functions. In particular, the middle frontal gyrus is highly activated during Chinese reading tasks ( Yan et al, 2021 ). Semantic incoherence increases the cognitive load of the language task, resulting in an increased need for attention allocation and more working memory consumption, which makes reading significantly more difficult.…”