title: Dopamine D1/D2 Receptor Activity in the Nucleus Accumbens Core But Not in the Nucleus Accumbens Shell and Orbitofrontal Cortex Modulates Risk-Based Decision Making.
abstract: BACKGROUND
  It is well known that brain dopamine (DA) signals support risk-based decision making; however, the specific terminal regions of midbrain DA neurons through which DA signals mediate risk-based decision making are unknown.
  
  
  METHODS
  Using microinfusions of the D1/D2 receptor antagonist flupenthixol, we sought to explore the role of D1/D2 receptor activity in the rat orbitofrontal cortex (OFC) and core and shell regions of the nucleus accumbens (AcbC and AcbS, respectively) in the regulation of risky choices. A risk-discounting task was used that involves choices between a certain small-reward lever that always delivered 1 pellet or a risky large-reward lever which delivered 4 pellets but had a decreasing probability of receiving the reward across 4 subsequent within-session trial blocks (100%, 50%, 25%, 12.5%). To validate task sensitivity to experimental manipulations of DA activity, we also examined the effects of systemic amphetamine and flupenthixol.
  
  
  RESULTS
  Systemic amphetamine increased while systemic flupenthixol reduced risky choices. Results further demonstrate that rats that received intra-AcbC flupenthixol were able to track increasing risk associated with the risky lever but displayed a generally reduced preference for the risky lever across all trial blocks, including in the initial trial block (large reward at 100%). Microinfusions of flupenthixol into the AcbS or OFC did not alter risk-based decision making.
  
  
  CONCLUSIONS
  Our data suggest that intra-AcbC D1/D2 receptor signaling does not support the ability to track shifts in reward probabilities but does bias risk-based decision making. That is, it increased the rats' preference for the response option known to be associated with higher risk-related costs.
authors.affiliation: Department Animal Physiology, University of Stuttgart, Stuttgart, Germany (Mrs Mai, Sommer, and Dr Hauber).
authors.forename: Bettina
authors.initials: B
authors.lastname: Mai
authors.affiliation: Department Animal Physiology, University of Stuttgart, Stuttgart, Germany (Mrs Mai, Sommer, and Dr Hauber).
authors.forename: Susanne
authors.initials: S
authors.lastname: Sommer
authors.affiliation: Department Animal Physiology, University of Stuttgart, Stuttgart, Germany (Mrs Mai, Sommer, and Dr Hauber). hauber@bio.uni-stuttgart.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hauber
mesh_terms: D000661:Amphetamine / Q000008:administration & dosage; D000818:Animals; D000697:Central Nervous System Stimulants / Q000008:administration & dosage; D002755:Choice Behavior / Q000187:drug effects / Q000502:physiology*; D018492:Dopamine Antagonists / Q000008:administration & dosage; D005475:Flupenthixol / Q000008:administration & dosage; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism*; D011336:Probability; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017447:Receptors, Dopamine D1 / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D012201:Reward; D012306:Risk; D012309:Risk-Taking
chemical_list: D000697:Central Nervous System Stimulants; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D000661:Amphetamine; D005475:Flupenthixol
keywords: Decision making; dopamine; nucleus accumbens; orbitofrontal cortex; rat; risk