Remitted major depression is characterized by reward network hyperactivation during reward anticipation and hypoactivation during reward outcomes.
BACKGROUND
Although functional brain imaging has established that individuals with unipolar major depressive disorder (MDD) are characterized by frontostriatal dysfunction during reward processing, no research to date has examined the chronometry of neural responses to rewards in euthymic individuals with a history of MDD.


METHODS
A monetary incentive delay task was used during fMRI scanning to assess neural responses in frontostriatal reward regions during reward anticipation and outcomes in 19 participants with remitted major depressive disorder (rMDD) and in 19 matched control participants.


RESULTS
During the anticipation phase of the task, the rMDD group was characterized by relatively greater activation in bilateral anterior cingulate gyrus, in right midfrontal gyrus, and in the right cerebellum. During the outcome phase of the task, the rMDD group was characterized by relatively decreased activation in bilateral orbital frontal cortex, right frontal pole, left insular cortex, and left thalamus. Exploratory analyses indicated that activation within a right frontal pole cluster that differentiated groups during reward anticipation predicted the number of lifetime depressive episodes within the rMDD group.


CONCLUSIONS
Replication with larger samples is needed.


CONCLUSIONS
Results suggest a double dissociation between reward network reactivity and temporal phase of the reward response in rMDD, such that rMDD is generally characterized by reward network hyperactivation during reward anticipation and reward network hypoactivation during reward outcomes. More broadly, these data suggest that aberrant frontostriatal response to rewards may potentially represent a trait marker for MDD, though future research is needed to evaluate the prospective utility of this functional neural endophenotype as a marker of MDD risk.
Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, United States. dichter@med.unc.edu
Gabriel S
GS
Dichter
Rachel V
RV
Kozink
F Joseph
FJ
McClernon
Moria J
MJ
Smoski
D000328:Adult; D059031:Anticipation, Psychological; D001921:Brain / Q000503:physiopathology*; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009042:Motivation; D011446:Prospective Studies; D012201:Reward; D055815:Young Adult