Monetary discounting and ventral striatal dopamine receptor availability in nontreatment-seeking alcoholics and social drinkers

Brandon G. Oberlin, Daniel S. Albrecht, Christine M. Herring, James W. Walters, Karen L. Hile, David A. Kareken, Karmen K. Yoder

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

Abstract Rationale: Dopamine (DA) in the ventral striatum (VST) has long been implicated in addiction pathologies, yet its role in temporal decision-making is not well-understood. Objectives: To determine if VST DA D<inf>2</inf> receptor availability corresponds with greater impulsive choice in both nontreatment-seeking alcoholics (NTS) and social drinkers (SD). Methods: NTS subjects (n=10) and SD (n=13) received PET scans at baseline with the D<inf>2</inf>/D<inf>3</inf> radioligand [<sup>11</sup>C]raclopride (RAC). Outside the scanner, subjects performed a delay discounting procedure with monetary rewards. RAC binding potential (BP<inf>ND</inf>) was estimated voxelwise, and correlations were performed to test for relationships between VST BP<inf>ND</inf> and delay discounting performance. Self-reported impulsivity was also tested for correlations with BP<inf>ND</inf>. Results: Across all subjects, greater impulsive choice for $20 correlated with lower BP<inf>ND</inf> in the right VST. NTS showed greater impulsive choice than SD and were more impulsive by self-report. Across all subjects, the capacity of larger rewards to reduce impulsive choice (the magnitude effect) correlated negatively (p=0.028) with problematic alcohol use (AUDIT) scores. Self-reported impulsivity did not correlate with BP<inf>ND</inf> in VST. Conclusions: Preference for immediate reinforcement may reflect greater endogenous striatal DA or lower D<inf>2</inf> number, or both. Alcoholic status did not mediate significant effects on VST BP<inf>ND</inf>, suggesting minimal effects from alcohol exposure. The apparent lack of BP<inf>ND</inf> correlation with self-reported impulsivity highlights the need for objective behavioral assays in the study of the neurochemical substrates of behavior. Finally, our results suggest that the magnitude effect may be more sensitive to alcohol-induced problems than single discounting measures.

Original languageEnglish (US)
Article number3850
Pages (from-to)2207-2216
Number of pages10
JournalPsychopharmacology
Volume232
Issue number12
DOIs
StatePublished - Jun 1 2015

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Keywords

  • Alcohol abuse
  • Ethanol
  • Impulsivity
  • Intertemporal choice
  • Mesolimbic
  • Neuroeconomics
  • Neuroimaging
  • Nucleus accumbens
  • Positron emission tomography
  • Raclopride

ASJC Scopus subject areas

  • Pharmacology

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