Advances in neuroimaging studies of thalamic abnormalities in children with attention deficit hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder whose core pathological mechanism is deeply rooted in the dysfunction of the cortico-striato-thalamo-cortical circuit. This review summarizes recent advances in magnetic resonance imaging (MRI) studies investigating thalamic abnormalities in children with ADHD, highlighting multidimensional pathological changes within the thalamus. Structurally, children with ADHD exhibit delayed overall thalamic volume development and significant atrophy in specific subregions, such as the ventral anterior nucleus, mediodorsal nucleus, and pulvinar. Regarding white matter microstructure, projection pathways from the thalamus to regions such as the motor cortex and striatum are impaired. Both resting-state and task-fMRI consistently demonstrate weakened cortical connectivity between the thalamus and both the default mode and dorsal attention networks. Furthermore, current evidence suggests that mainstream pharmacological treatments, particularly methylphenidate and atomoxetine, effectively promote structural remodeling and the "normalization" of network functions in the aberrant thalamus. Additionally, multidimensional neuroimaging metrics of the thalamus demonstrate substantial potential as objective biomarkers for assessing genetic risk, classifying clinical subtypes, and predicting treatment outcomes. Ultimately, this review emphasizes that the thalamus is not merely a passive sensory relay station, but an active gatekeeper regulating cognition and behavior. Its structural and functional abnormalities constitute a central hub in the pathogenesis of ADHD. Supported by future large-scale machine learning and longitudinal studies, the thalamus holds promise as a crucial biomarker for the precise diagnosis and personalized targeted intervention of ADHD.