Reduced striatal activation in females with major depression during the processing of affective stimuli

The extent to which affective reactivity and associated neural underpinnings are altered by depression remains equivocal. This study assessed striatal activation in fifty-one unmedicated female participants meeting DSM-IV criteria for Major Depressive Disorder (MDD) and 61 age-matched healthy females (HC) aged 17-63 years. Participants completed an affective reactivity functional magnetic resonance imaging task. Data were preprocessed using SPM8, and region-of-interest analyses were completed using MarsBaR to extract caudate, putamen, and nucleus accumbens (NAcc) activation. General linear repeated measure ANOVAs were used to assess group differences and correlational analyses were used to measure the association between activation, depression severity, and anhedonia. Main effects of hemisphere, valence, and group status were observed, with MDD participants demonstrating decreased striatal activation compared with HC. Across groups and valence types, the left hemisphere demonstrated greater activation than the right hemisphere in the putamen and nucleus accumbens, whereas the right hemisphere demonstrated greater activation than the left in the caudate. Additionally, unpleasant stimuli elicited greater activation than pleasant and neutral stimuli in the caudate and putamen, and unpleasant stimuli elicited greater activation than neutral stimuli in the NAcc. There were no significant associations between activation, depression severity, and anhedonia. Overall, depression was characterized by reduced affective reactivity in the striatum, regardless of stimuli valence, supporting the emotion context insensitivity model of depression.