Time Course of Regional Brain Activity Associated With Top-Down Attentional Control in Depression

157 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009.A network consisting of dorsal anterior cingulate cortex (dACC) and left dorsal lateral prefrontal cortex (LDLPFC) has been implicated in cognitive control. Very few studies have investigated how this network is altered in psychopathology, despite evidence that depression and anxiety are associated with cognitive control impairments. In the present studies, participants with a history of depression, comorbid depression/anxiety, or neither provided fMRI and EEG data during a color-word Stroop task. fMRI guided development of an EEG source model to characterize the time course of activity in and relationships among specific brain regions, including LDLPFC (300-440 ms) and dACC (520-680 ms). dACC activity mediated the relationship between LDLPFC activity and Stroop interference (incongruent reaction time minus congruent reaction time). Increased LDLPFC activity was related to better Stroop performance, mediated by dACC. Depression moderated the relationship between LDLPFC and dACC. The effect of LDLPFC on dACC was larger at lower levels of depression. In contrast, anxiety moderated the relationship between dACC and Stroop interference, stronger at higher levels of worry. Categorical analyses using DSM-IV-TR diagnoses provided additional evidence for processing abnormalities in depression as indexed by scalp ERP components (N200 and N450). Overall, results suggest that depression and anxiety play temporally and functionally different roles in this network involved in top-down attention control.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD