An fMRI study of emotional face processing in adolescent major depression

Abstract

OBJECTIVE: Major Depressive Disorder (MDD) is a serious, often chronic illness associated with significant impairment and suicide. MDD often begins during adolescence when brain areas that regulate emotion processing are still maturing. To expand upon our limited understanding of the neurobiological underpinnings of MDD early on in development, this study examined function within fronto-limbic neural circuits in response to an emotional faces task among depressed adolescents and healthy controls (HC) using functional magnetic resonance imaging (fMRI). METHOD: 34 adolescents with MDD (12 medicated, 22 unmedicated) and 16 healthy age and gender matched controls completed an emotional faces task where BOLD response was examined when viewing happy and fearful faces (presented in a block design) during fMRI. Scanning was completed using a 3.0 Tesla scanner. Data preprocessing and analysis was carried out using FEAT in FSL. Whole brain group level analyses were conducted using a mixed-effects model (FLAME) with cluster-wise significant testing (min Z=2.32; cluster significance = p<0.05, corrected). RESULTS: In response to viewing fearful versus happy faces, MDD showed reduced activation in areas of the right thalamus, right insula, and right hippocampus compared to HC. CONCLUSION: Results suggest that emotion processing in adolescent MDD is associated with abnormalities in subcortical and paralimbic brain regions within the broader fronto-limbic neural network. It is possible that these findings reflect deficits in depressed adolescents' ability to elicit cognitive control from higher cortical regions and to accurately respond to and process the emotional significance of fearful stimuli.