Dopamine d1 receptor activity in the basolateral amygdala is important for mediating fear, reward and safety discrimination learning

Post traumatic stress disorder (PTSD) patients frequently show impairment in safety learning (Jovanovic, Kazama, Bachevalier, & Davis, 2012). Since the amygdala is known to be critical for emotional processing(Wassum & Izquierdo, 2015) and dopamine signaling in the amygdala is important for mediating both fear and reward learning, current experiments examined the role of dopamine signaling in the BLA in mediating both safety learning and reward seeking. We manipulated dopamine D1 receptor activity with a D1 receptor agonist (SKF 38393) or D1 receptor antagonist (SCH23390) either systemically or infused directly into the BLA 20 minutes prior to training rats in a fear-safety-reward cue discrimination learning task (Sangha, Chadick, & Janak, 2013). Systemic administration of either the D1 receptor agonist or antagonist impaired fear and safety discrimination learning. The systemic administration of the D1 receptor agonist, but not the antagonist, also impaired discriminative fear and discriminative reward seeking. BLA infusion of the agonist, but not the antagonist, replicated the impairment in fear and safety discrimination learning but not discriminative reward seeking. This study demonstrates that D1 receptor activity in the BLA is not needed for fear learning, safety learning or discriminative reward seeking, but an increase in dopamine D1 receptor activity within the BLA impairs fear suppression in the presence of the safety signal