The Effects of Cocaine-Paired Environmental Stimuli on Impulsive Decision Making (2013)

Undergraduates: Ana Balta, Dr. Xiaohu Xie

Faculty Advisor: Rita Lokensgard
Department: Psychology & Neuroscience

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Stimulation of nicotinic acetylcholine receptors (nAChR) is critical for drug context-induced impulsive decision-making. Given that α7 nAChR is highly expressed in the OFC, we investigated the role of α7 nAChRs in the OFC in drug context-induced impulsive decision making. To this end, we trained rats to achieve stable performance on a delay discounting task, which involved lever press-based choice between a single food pellet (small reward) available immediately and three food pellets (large reward) available after a 10-, 20-, 40-, or 60-s time delay. Following Pavlovian context-cocaine conditioning, delay discounting performance was assessed in the previously cocaine-paired or saline-paired context using a counterbalanced within-subject design. Prior to testing, rats received intra-OFC infusions of vehicle (PBS; 0.5 ¿l/site) or MLA (α7 nAChR antagonist; 2 ¿g/0.5 ¿l/site). Following vehicle pretreatment, rats exhibited greater decrease in preference for the large reward as a function of delay duration in the cocaine-paired context, relative to the saline-paired context. Furthermore, intra-OFC infusion of 2¿g MLA attenuated the decrease in preference for the large reward in the cocaine-paired context, but not in the saline-paired context, as compared to vehicle. Thus, stimulation of α7 nAChRs in the OFC is critical for drug context-induced impulsive decision making.