fMRI of alterations in reward selection, anticipation, and feedback in major depressive disorder

Abstract

The purpose of the present investigation was to evaluate reward processing in unipolar major depressive disorder (MDD). Specifically, we investigated whether adults with MDD demonstrated hyporesponsivity in striatal brain regions and/or hyperresponsivity in cortical brain regions involved in conflict monitoring using a Wheel of Fortune task designed to probe responses during reward selection, reward anticipation, and reward feedback. Functional magnetic resonance imaging (fMRI) data indicated that the MDD group was characterized by reduced activation of striatal reward regions during reward selection, reward anticipation, and reward feedback, supporting previous data indicating hyporesponsivity of reward systems in MDD. Support was not found for hyperresponsivity of cognitive control regions during reward selection or reward anticipation. Instead, MDD participants showed hyperresponsivity in orbitofrontal cortex, a region associated with assessment of risk and reward, during reward selection, as well as decreased activation of the middle frontal gyrus and the rostral cingulate gyrus during reward selection and anticipation. Finally, depression severity was predicted by activation in bilateral midfrontal gyrus during reward selection. Results indicate that MDD is characterized by striatal hyporesponsivity, and that future studies of MDD treatments that seek to improve responses to rewarding stimuli should assess striatal functioning.

Figures

Figure 1

The Wheel of Fortune (WoF) task (Ernst et al., 2004). (a) The four different types of wheels; (b) The timing of three processes that occurred during the task, i.e., reward selection, reward anticipation, and reward feedback.

Figure 2

Reward selection (top) and anticipation (bottom) fMRI results (money vs. control). Red areas depict regions with greater activation in the control than the depressed group; blue areas depict regions with greater activation in the depressed than the control group.

Figure 3

Reward feedback fMRI results for win (top) and non-win (bottom) trials relative to control feedback. Red areas depict regions with greater activation in the control than the MDD group; blue areas depict regions with greater activation in the MDD than the control group.