Is decreased prefrontal cortical sensitivity to monetary reward associated with impaired motivation and self-control in cocaine addiction?
OBJECTIVE
This study attempted to examine the brain's sensitivity to monetary rewards of different magnitudes in cocaine abusers and to study its association with motivation and self-control.


METHODS
Sixteen cocaine abusers and 13 matched healthy comparison subjects performed a forced-choice task under three monetary value conditions while brain activation was measured with functional magnetic resonance imaging. Objective measures of state motivation were assessed by reaction time and accuracy, and subjective measures were assessed by self-reports of task engagement. Measures of trait motivation and self-control were assessed with the Multidimensional Personality Questionnaire.


RESULTS
The cocaine abusers demonstrated an overall reduced regional brain responsivity to differences between the monetary value conditions. Also, in comparison subjects but not in cocaine abusers, reward-induced improvements in performance were associated with self-reports of task engagement, and money-induced activations in the lateral prefrontal cortex were associated with parallel activations in the orbitofrontal cortex. For cocaine abusers, prefrontal cortex sensitivity to money was instead associated with motivation and self-control.


CONCLUSIONS
These findings suggest that in cocaine addiction 1) activation of the corticolimbic reward circuit to gradations of money is altered; 2) the lack of a correlation between objective and subjective measures of state motivation may be indicative of disrupted perception of motivational drive, which could contribute to impairments in self-control; and 3) the lateral prefrontal cortex modulates trait motivation and deficits in self-control, and a possible underlying mechanism may encompass a breakdown in prefrontal-orbitofrontal cortical communication.
Goldstein
Rita Z
RZ
State University of New York at Stony Brook, Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000, USA. rgoldstein@bnl.gov
Alia-Klein
Nelly
N
Tomasi
Dardo
D
Zhang
Lei
L
Cottone
Lisa A
LA
Maloney
Thomas
T
Telang
Frank
F
Caparelli
Elisabeth C
EC
Chang
Linda
L
Ernst
Thomas
T
Samaras
Dimitris
D
Squires
Nancy K
NK
Volkow
Nora D
ND
D000328:Adult; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology; D019970:Cocaine-Related Disorders / Q000175:diagnosis / Q000523:psychology*; D003216:Conditioning, Operant / Q000502:physiology; D004328:Drive; D005260:Female; D006801:Humans; D008032:Limbic System / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D008297:Male; D009042:Motivation; D009434:Neural Pathways / Q000502:physiology; D010100:Oxygen / Q000097:blood; D010555:Personality Inventory; D017397:Prefrontal Cortex / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012201:Reward; D011795:Surveys and Questionnaires; D013647:Task Performance and Analysis; D014040:Token Economy
D010100:Oxygen