Principal Investigator
Mani Pavuluri, MD, PhD

This study proposes to examine the function and structure of fronto-limbic and fronto-striatal circuits which serve as the interface between cognitive and affective function. The task- and disorder-specific nature of these neural operations provides an opportunity to probe the interface of affective and cognitive operations and to delineate the distinct neural signatures of PBD and ADHD. To do this, the research team will use an affective color matching task and response inhibition task with fMRI to engage the attentional circuitry with and without emotional challenge. They will also simultaneously characterize the integrity of white matter tracts using high resolution diffusion tensor (DTI) imaging. Preliminary studies suggest that in the fMRI studies the subcortical regions will be differentially engaged in PBD and ADHD, with increased amygdala activity in subjects with PBD and more prominent abnormalities in caudate of ADHD subjects. In the DTI studies, based on pilot data, it is predicted that patients with PBD will have lower fractional anisotropy (FA) and regional fiber coherence index (r-FCI) and greater apparent diffusion co-efficient (ADC) than ADHD in the uncinate fasiculus that stretches between frontal and limbic regions while patients with ADHD will have lower FA and r-FCI, and greater ADC than PBD in the superior and anterior region of the internal capsule, the white matter tracts between prefrontal regions and the caudate. The complementary fMRI and DTI data will be fused to show how the brain functional and structural circuitry based differences can demarcate PBD from ADHD.

FUNDING: NIMH 1RC1MH088462 -01