David Nguyen1, Victoria Fugariu1, Suzanne Erb1, Rutsuko Ito2. 1. Department of Psychology, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada. 2. Department of Psychology, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada. rutsuko.ito@utoronto.ca.
Abstract
RATIONALE: Approach and avoidance decisions are made when an animal experiences a state of motivational conflict inflicted by stimuli imbued with both positive and negative valences. The nucleus accumbens (NAc), a site where valenced information and action selection converge, has recently been found to be critically involved in the resolution of approach-avoidance conflict. However, the individual roles of the region's dopamine receptor D1 (D1R)- and D2 (D2R)-expressing medium spiny neurons (MSNs) in regulating conflict resolution have not been well established. OBJECTIVES: Here, we examined the roles of NAc D1R and D2R in cue-elicited approach-avoidance decision-making. METHODS: Using a conditioned mixed-valence conflict paradigm, rats were initially trained in a radial maze to associate separate visuotactile cues with sucrose reward, foot shock punishment, and no outcome. Following acquisition of the cue-outcome associations, rats were subjected to a conditioned approach-avoidance conflict scenario, in which they were presented with a maze arm containing a superimposition of the reward and punishment cues, and another arm containing neutral cues. RESULTS: Post-training intra-NAc D1R antagonism (SCH23390) led to an avoidance of the arm containing the mixed-valence cue over the neutral arm, whereas intra-NAc D2R antagonism (sulpiride) resulted in rats exhibiting a preference for the mixed-valence arm. CONCLUSION: Our results suggest that NAc D1R and D2R exert differential control over decision-making involving cue-elicited approach-avoidance conflict resolution.
RATIONALE: Approach and avoidance decisions are made when an animal experiences a state of motivational conflict inflicted by stimuli imbued with both positive and negative valences. The nucleus accumbens (NAc), a site where valenced information and action selection converge, has recently been found to be critically involved in the resolution of approach-avoidance conflict. However, the individual roles of the region's dopamine receptor D1 (D1R)- and D2 (D2R)-expressing medium spiny neurons (MSNs) in regulating conflict resolution have not been well established. OBJECTIVES: Here, we examined the roles of NAc D1R and D2R in cue-elicited approach-avoidance decision-making. METHODS: Using a conditioned mixed-valence conflict paradigm, rats were initially trained in a radial maze to associate separate visuotactile cues with sucrose reward, foot shock punishment, and no outcome. Following acquisition of the cue-outcome associations, rats were subjected to a conditioned approach-avoidance conflict scenario, in which they were presented with a maze arm containing a superimposition of the reward and punishment cues, and another arm containing neutral cues. RESULTS: Post-training intra-NAc D1R antagonism (SCH23390) led to an avoidance of the arm containing the mixed-valence cue over the neutral arm, whereas intra-NAc D2R antagonism (sulpiride) resulted in rats exhibiting a preference for the mixed-valence arm. CONCLUSION: Our results suggest that NAc D1R and D2R exert differential control over decision-making involving cue-elicited approach-avoidance conflict resolution.
Authors: Francesca Managò; Claudio Castellano; Alberto Oliverio; Andrea Mele; Elvira De Leonibus Journal: Learn Mem Date: 2008-12-30 Impact factor: 2.460