title: Dissociable hippocampal and amygdalar D1-like receptor contribution to discriminated Pavlovian conditioned approach learning.
abstract: Pavlovian conditioning is an elementary form of reward-related behavioral adaptation. The mesolimbic dopamine system is widely considered to mediate critical aspects of reward-related learning. For example, initial acquisition of positively-reinforced operant behavior requires dopamine (DA) D1 receptor (D1R) activation in the basolateral amygdala (BLA), central nucleus of the amygdala (CeA), and the ventral subiculum (vSUB). However, the role of D1R activation in these areas on appetitive, non-drug-related, Pavlovian learning is not currently known. In separate experiments, microinfusions of the D1-like receptor antagonist SCH-23390 (3.0 nmol/0.5 μL per side) into the amygdala and subiculum preceded discriminated Pavlovian conditioned approach (dPCA) training sessions. D1-like antagonism in all three structures impaired the acquisition of discriminated approach, but had no effect on performance after conditioning was asymptotic. Moreover, dissociable effects of D1-like antagonism in the three structures on components of discriminated responding were obtained. Lastly, the lack of latent inhibition in drug-treated groups may elucidate the role of D1-like in reward-related Pavlovian conditioning. The present data suggest a role for the D1 receptors in the amygdala and hippocampus in learning the significance of conditional stimuli, but not in the expression of conditional responses.
authors.affiliation: Department of Psychology, University of Wisconsin-Whitewater, 800 N. Main St., Whitewater, WI 53719, United States. Electronic address: andrzejm@uww.edu.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Andrzejewski
authors.affiliation: Department of Psychology, University of Wisconsin-Madison, United States.
authors.forename: Curtis
authors.initials: C
authors.lastname: Ryals
mesh_terms: D000679:Amygdala / Q000187:drug effects*; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001552:Benzazepines / Q000819:agonists; D003214:Conditioning, Classical / Q000187:drug effects*; D003216:Conditioning, Operant / Q000187:drug effects; D004193:Discrimination Learning / Q000187:drug effects*; D018492:Dopamine Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000378:metabolism*
chemical_list: D001552:Benzazepines; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; C534628:SCH 23390
keywords: Amygdala; D1; Dopamine; Pavlovian conditioned approach; Rats; Subiculum