A double dissociation of ventromedial prefrontal cortical responses to sad and happy stimuli in depressed and healthy individuals.
BACKGROUND
The ventromedial prefrontal cortex (VMPFC) is a region implicated in the assessment of the rewarding potential of stimuli and may be dysfunctional in major depressive disorder (MDD). The few studies examining prefrontal cortical responses to emotive stimuli in MDD have indicated increased VMPFC responses to pleasant images but decreased responses to sad mood provocation when compared with healthy individuals. We wished to corroborate these results by examining neural responses to personally relevant happy and sad stimuli in MDD and healthy individuals within the same paradigm.


METHODS
Neural responses to happy and sad emotional stimuli (autobiographical memory prompts and congruent facial expressions) were measured using blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) in MDD (n = 12) and healthy (n = 12) individuals.


RESULTS
Increased and decreased responses in VMPFC were observed in MDD and healthy individuals, respectively, to happy stimuli, whereas the pattern was reversed for MDD and healthy individual responses to sad stimuli. These findings were not explained by medication effects in depressed individuals.


CONCLUSIONS
These findings indicate a double dissociation of the pattern of VMPFC response to happy and sad stimuli in depressed and healthy individuals and suggest abnormal reward processing in MDD.
Department of Psychological Medicine, Institute of Psychiatry, London, England. p.keedwell@iop.kcl.ac.uk
Paul A
PA
Keedwell
Chris
C
Andrew
Steven C R
SC
Williams
Mick J
MJ
Brammer
Mary L
ML
Phillips
D000328:Adult; D001931:Brain Mapping; D003863:Depression / Q000523:psychology*; D004644:Emotions / Q000502:physiology*; D005149:Facial Expression; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D005712:Galvanic Skin Response / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual / Q000502:physiology*; D017397:Prefrontal Cortex / Q000098:blood supply / Q000503:physiopathology*
D010100:Oxygen