Prefrontal cortical contribution to risk-based decision making.
Damage to various regions of the prefrontal cortex (PFC) impairs decision making involving evaluations about risks and rewards. However, the specific contributions that different PFC subregions make to risk-based decision making are unclear. We investigated the effects of reversible inactivation of 4 subregions of the rat PFC (prelimbic medial PFC, orbitofrontal cortex [OFC], anterior cingulate, and insular cortex) on probabilistic (or risk) discounting. Rats were well trained to choose between either a "Small/Certain" lever that always delivered 1 food pellet, or another, "Large/Risky" lever, which delivered 4 pellets, but the probability of receiving reward decreased across 4 trial blocks (100%, 50%, 25%, and 12.5%). Infusions of gama-aminobutyric acid agonists muscimol/baclofen into the medial PFC increased risky choice. However, similar medial PFC inactivations decreased risky choice when the Large/Risky reward probability increased over a session. OFC inactivation increased response latencies in the latter trial blocks without affecting choice. Anterior cingulate or insular inactivations were without effect. The effects of prelimbic inactivations were not attributable to disruptions in response flexibility or judgments about the relative value of probabilistic rewards. Thus, the prelimbic, but not other PFC regions, plays a critical role in risk discounting, integrating information about changing reward probabilities to update value representations that facilitate efficient decision making.
St Onge
Jennifer R
JR
Department of Psychology and Brain Research Center, University of British Columbia, Vancouver, BC V6T 1Z4, Canada V6T 1Z4.
Floresco
Stan B
SB
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology; D003071:Cognition / Q000502:physiology; D003657:Decision Making / Q000187:drug effects / Q000502:physiology*; D056344:Executive Function / Q000502:physiology; D018755:GABA Agonists / Q000494:pharmacology; D006179:Gyrus Cinguli / Q000187:drug effects / Q000502:physiology; D008297:Male; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012201:Reward; D018570:Risk Assessment / Q000379:methods; D012309:Risk-Taking
D018755:GABA Agonists