Functional Connectivity Alterations in Developmental Dyslexia: A Meta-Analysis of Task-Based and Resting-State fMRI...

Developmental dyslexia (DD) is a prevalent neurodevelopmental disorder that significantly affects academic learning and social development. Although numerous brain regions have been implicated in DD under both task-based and resting-state conditions, dysfunctions in large-scale functional coordination across brain systems in DD remains poorly understood. Using AES-SDM, we conducted a meta-analysis of seed-based whole-brain functional connectivity (FC) studies, including 12 task-based studies with 226 dyslexics and 232 age-matched controls, and 7 resting-state studies with 120 dyslexics and 145 controls. Results revealed consistently reduced FC between the left inferior frontal gyrus (IFG) and the left fusiform gyrus (FFG) in dyslexics compared with age-matched controls across both task and resting states, suggesting a core neural pathway underlying DD. In addition, task-specific abnormalities were identified, including hypoconnectivity between the left IFG and the right cerebellum, and hyperconnectivity between the left IFG and the bilateral angular gyrus (AG), anterior cingulate cortex (ACC), and left thalamus. By contrast, resting-state analyses identified additional hypoconnectivity between the left FFG and the posterior cingulate cortex (PCC). Together, these findings suggest that DD is associated with widespread disruption in functional integration across the brain, shedding new light on its neural mechanisms of DD and pointing to potential connectivity-based biomarkers for diagnosis. SUMMARY: Dyslexics exhibited consistent hypoconnectivity between the left inferior frontal gyrus and the left fusiform gyrus across both task and resting conditions. Under the task condition, dyslexics showed specific hypoconnectivity between the left inferior frontal gyrus and the right cerebellum, and hyperconnectivity with the bilateral angular gyrus, anterior cingulate cortex, and left thalamus. Under the resting condition, dyslexics showed specific hypoconnectivity between the left fusiform gyrus and the posterior cingulate cortex.