Neuroimaging Correlates of Emotional Response-Inhibition Discriminate Between Young Depressed Adults With and Without Sub-threshold Bipolar Symptoms (Emotional Response-inhibition in Young Depressed Adults)

ABSTRACT Background Many subjects with major depression (MDD) exhibit subthreshold mania symptoms (MDD+). This study investigated, for the first time, using emotional inhibition tasks, whether the neural organization of MDD+ subjects is more similar to bipolar depression (BDD) or to MDD subjects without subthreshold bipolar symptoms (MDD-). Method This study included 118 medication-free young adults (15 – 30 yrs.): 20 BDD, 28 MDD+, 41 MDD- and 29 HC subjects. Participants underwent fMRI during emotional and non-emotional Go/No-go tasks during which they responded for Go stimuli and inhibited response for happy, fear, and non-emotional (gender) faces No-go stimuli. Univariate linear mixed-effects (LME) analysis for group effects and multivariate Gaussian Process Classifier (GPC) analyses were conducted. RESULTS MDD- group compared to both the BDD and MDD+ groups, exhibited significantly lower activation in parietal, temporal and frontal regions (cluster-wise corrected p LIMITATIONS Results also need to be tested in a different independent dataset. CONCLUSION Using an fMRI emotional Go-Nogo task, MDD- subjects can be discriminated from BDD and MDD+ subjects.