title: The effects of amphetamine sensitization on conditioned inhibition during a Pavlovian-instrumental transfer task in rats.
abstract: BACKGROUND
  Psychostimulant sensitization heightens behavioral and motivational responses to reward-associated stimuli; however, its effects on stimuli associated with reward absence are less understood.
  
  
  OBJECTIVE
  We examined whether amphetamine sensitization alters performance during Pavlovian-instrumental transfer (PIT) to conditioned excitors and inhibitors. We further sought to characterize the effects of amphetamine sensitization on learning versus performance by exposing rats to amphetamine prior to Pavlovian training or between training and test.
  
  
  METHODS
  Adult male Long-Evans rats were given conditioned inhibition (A+/AX-) and Pavlovian (B+) training, followed by variable-interval instrumental conditioning. Rats were sensitized to D-amphetamine (2 mg/kg daily injections for 7 days) or served as non-exposed controls. Rats were given a PIT test, in which they were presented with stimulus B alone or in compound with the conditioned inhibitor (BX).
  
  
  RESULTS
  During the PIT test, control rats significantly reduced instrumental responding on BX trials (to approximately 50 % of responding to B). Amphetamine sensitization prior to Pavlovian conditioning increased lever pressing on BX trials and reduced lever pressing on B trials compared to controls. Amphetamine sensitization between training and test increased lever pressing on B and BX trials compared to controls. No effects of sensitization were observed on conditioned food cup approach.
  
  
  CONCLUSIONS
  Amphetamine sensitization increases instrumental responding during PIT to a conditioned inhibitor by enhancing the excitation of conditioned stimuli and reducing the inhibition of conditioned inhibitors.
authors.affiliation: Department of Psychology, Rutgers University, 101 Warren Street, Newark, NJ, 07102, USA, shiflett@psychology.rutgers.edu.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Shiflett
authors.forename: Meaghan
authors.initials: M
authors.lastname: Riccie
authors.forename: RoseMarie
authors.initials: R
authors.lastname: DiMatteo
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects*; D003913:Dextroamphetamine / Q000008:administration & dosage / Q000494:pharmacology*; D007266:Inhibition, Psychological; D007858:Learning / Q000187:drug effects; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D012201:Reward; D014163:Transfer, Psychology / Q000187:drug effects*
chemical_list: D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine