| The present study represents an attempt to integrate information-processing theories of depression with neuroanatomical models of this disorder. In Study 1A, functional magnetic resonance imaging (fMRI) was used to identify the neural correlates of emotional face processing in individuals diagnosed with Major Depressive Disorder (MDD) and nondepressed, nonpsychiatric controls as they performed a gender decision task. Contrary to predictions derived from previous behavioral research, both groups of participants displayed equal levels of emotional interference on the gender decision task. In contrast, their neural response to emotional faces was strikingly different. Four main brain findings are highlighted. First, relative to the nondepressed subjects, subjects with MDD broadly failed to respond differentially to negative and neutral faces. Second, both groups of participants displayed differential activation to angry and neutral faces in the affective division of the anterior cingulate (AC), a region previously identified in behavioral interference tasks. Interestingly, whereas depressed participants displayed an increase in activation in this region, nondepressed participants displayed a decrease in AC activation. Third, depressed participants displayed a bilateral fusiform response to negative faces that was not seen in the nondepressed participants. Finally, depressed participants exhibited deactivation in several neural areas in response to happy, compared to neutral, faces. In Study 1B, the results of these neural contrast analyses were correlated with the percent of change in depressive symptoms seven months following their initial participation. Importantly, whereas greater neural response to negative faces in regions previously found to be associated with visual attention and reward processing predicted failure to recover from depression, greater brain response to happy faces predicted a positive symptom course. The divergent neural response of depressed and nondepressed individuals to emotional faces may reflect differences in attentional allocation and responsivity to interpersonal emotional information. Moreover, the results of Study 1B suggest that depressed participants who respond “more like normal” to affective stimuli in brain areas associated with attention and reward may surprisingly exhibit symptom worsening rather than improvement. The need for further research incorporating both behavioral and neural measures of abnormal affective processing in depression is emphasized. |
