Structural and Functional Connectivity of Frontostriatal and Frontoparietal Networks as Endophenotypes of ADHD

Attention deficit/hyperactivity disorder (ADHD) is a common, impairing, clinically and genetically heterogeneous neuropsychiatric disorder with lifelong executive dysfunctions. The ultimate goal of this 3-year case-control imaging genomic study with unaffected siblings and typically developing (TD) children as controls is to identify useful imaging endophenotype for ADHD by investigating the structural connectivity, as assessed by diffusion spectrum imaging (DSI), and functional connectivity, as assessed by resting-state fMRI (rsfMRI) of brain regions related to cognitive/executive controls with regards to the ADHD status and the presence of dopamine transporter gene variants (DAT1). Specific Aims:

1. 1.to validate the executive functions, visuospatial memory, and structural and functional connectivity in frontostriatal, and frontoparietal circuitries as effective neurocognitive endophenotypes;
2. 2.to correlate the data from structural and functional connectivity, neuropsychology, and ADHD core symptoms stratifying by the presence of ADHD, proband-unaffected sibling dyads, and the presence of DAT1 variant; and
3. 3.To investigate reported candidate genes, in addition to DAT1 variant, related to dopamine and noradrenergic neurotransmitter systems in the association with neurocognitive endophenotypes such as DRD1, DRD2, DRD4, DRD5, DBH, MAO-A, ADRA2A, ADRA2C, NET, and COMT.