Functional neuroimaging and cognitive control process in depressed bipolar youth
Objective: Bipolar disorder (BP) in youth is often manifested by periods of depression during which the child has significant cognitive and psychosocial problems and increased risk for suicide; however, no study in BP youth has investigated neural activity involved in cognitive control during depression. We aimed to identify functional abnormalities in dorsolateral (DLPFC) and ventrolateral (VLPFC) prefrontal cortex during cognitive control process in depressed bipolar (BP) youth compared to healthy controls (HC).
Methods: We studied percentage change in Blood Oxygen Level Dependent (BOLD) signals on fMRI during NoGo and NoGo vs. Go conditions of the Go/NoGo task in 5 depressed bipolar youth compared to 5 age- and gender-matched HC. We compared the task performance (accuracy and reaction time) of depressed BP and healthy control subjects and searched for correlation between depression scores on Child Depression Rating Scale-Revised (CDRS-R) and DLPFC/VLPFC activity.
Results: Percentage change in BOLD signal was significantly higher in HC compared to depressed BP during both NoGo and NoGo vs. Go conditions of the Go/NoGo task (p< .05, uncorrected). The accuracy and reaction time during the Go/NoGo task were not significantly different between depressed BP and HC youth. Depression scores in depressed BP youth were negatively correlated with DLPFC/VLPFC activity.
Conclusions: Similar to the studies in adults, our preliminary results indicated abnormal neural activity in depressed BP youth during cognitive control. We need larger and longitudinal studies to investigate clinical correlations and persistence of this neural abnormality across different mood states.