Keywords: Bipolar Disorder | Depression | Neuroscience
Presentation Type: Symposium
There is growing evidence that risk for bipolar disorder and unipolar depression (without a history of hypomania/mania) are characterized by distinct and opposite profiles of reward processing and reward-related neural activation. Specifically, bipolar disorder, and particularly risk for hypomania/mania, is characterized by a hypersensitivity to reward-relevant stimuli. By contrast, major depressive disorder (MDD) is characterized by a blunted sensitivity to reward-relevant stimuli and abnormally reduced reward-related neural activation. Collectively, these data suggest that risk for bipolar disorder versus unipolar depression is characterized by distinct and opposite profiles of reward processing. Extending this literature, this talk presents multiple studies examining both functional and structural connectivity within the cortico-striatal reward circuit among individuals with MDD and individuals at risk for bipolar. Using analyses of functional connectivity (i.e., psychophysiological interaction analysis), we report that MDD is characterized by a negative coupling between activation in the medial orbitofrontal cortex (OFC) and the nucleus accumbens (NAcc) during reward processing. This suggests that unipolar depression may be characterized by an inability of the prefrontal cortex to dynamically engage sub-cortical reward processing regions when encountering rewarding stimuli. By contrast, using analyses of structural connectivity (i.e., diffusion tensor imaging), we report that risk for bipolar disorder is characterized by enhanced white matter integrity between the NAcc and the medial OFC. This suggests that individuals with bipolar disorder may abnormally amplify sub-cortical reward processing via the prefrontal cortex. These results have important implications for unpacking the temporal dynamics of top-down (OFC-to-NAcc) versus bottom-up (NAcc-to-OFC) reward processing abnormalities in mood disorders.
Associate Professor, Department of Psychology
Friday, November 17
8:30 AM – 10:00 AM
Saturday, November 18
10:15 AM – 11:45 AM
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