Objective: To examine the impact of depression on neural mechanisms associated with outcome processing (rewarding and punishing outcomes) in persons with traumatic brain injury (TBI).
Setting: Kessler Foundation's Rocco Ortenzio Neuroimaging Center.
Participants: A total of 16 adults with moderate to severe TBI.
Main measures: Chicago Multiscale Depression Inventory (CMDI); Behavioral Inhibition/Behavioral Activation Scale (BIS/BAS); functional MRI of the head while performing a gambling task, with a reward (+$1.00) and punishment (-$0.50).
Results: Individuals with TBI reporting high depressive symptomatology exhibited increased activation in the ventromedial prefrontal cortex (VMPFC) and striatum during presentation of rewarding outcomes compared with individuals with TBI reporting low depressive symptomatology. Punishing outcome presentation was not associated with any change in brain activation. No differences in volume of the striatum and VMPFC were observed between groups.
Conclusions: Current findings provide the first evidence of differences in neural mechanisms underlying outcome processing between individuals with TBI with and without depression. The results suggest that depressive symptomatology might have a different effect on individuals with TBI than what is typically observed in individuals without TBI reporting with depression, with the possibility of rewards becoming more reinforcing as depressive symptomatology increases. Future studies should explore the potential implications of behavioral responses to rewards and punishments in TBI and how they can affect rehabilitation approaches and activities of daily living.