title: Sensory reinforcement as a predictor of cocaine and water self-administration in rats.
abstract: BACKGROUND
  The ability of locomotor activity in a novel environment (Loco) and visual stimulus reinforcement (VSR) to predict acquisition of responding for cocaine and water reinforcers in the absence of explicit audiovisual signals was evaluated.
  
  
  METHODS
  In Experiment 1 (Exp 1), rats (n = 60) were tested for VSR, followed by Loco, and finally acquisition of responding for cocaine (0.3 mg/kg/inf). In Experiment 2 (Exp 2), rats (n = 32) were tested for VSR, followed by Loco, and finally acquisition of responding for water (0.01 mL/reinforcer).
  
  
  RESULTS
  There were three main findings. First, Loco and VSR were significantly associated (Exp 1: r = 0.49, p < 0.00; Exp 2: r = 0.35, p < 0.05). Second, neither Loco (r = .00, p = 0.998) nor VSR (r = -0.12, p = 0.352) predicted acquisition of cocaine SA. Third, in the subgroup of animals that acquired cocaine SA, VSR (r = 0.41, p < 0.01) but not Loco (r = 0.28, p = 0.10) was positively associated with operant responding for cocaine. Both Loco and VSR (Loco: r = 0.37, p < 0.04; VSR: r = 0.51, p < 0.00) were positively associated with operant responding for water reinforcers.
  
  
  CONCLUSIONS
  The results indicate that VSR is at least as good a predictor of cocaine reinforced responding as Loco. VSR was predictive of operant responding for both drug and water reinforcers, while Loco was found to be predictive of responding only for water reinforcers. In studies that present visual stimuli in association with drug delivery, Loco may be predicting acquisition of responding for VSR rather than drug.
authors.affiliation: Department of Psychology, State University of New York at Buffalo, Park Hall Room 204, Buffalo, NY 14260, USA. agancarz@ria.buffalo.edu
authors.forename: Amy M
authors.initials: AM
authors.lastname: Gancarz
authors.forename: Mykel A
authors.initials: MA
authors.lastname: Robble
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kausch
authors.forename: David R
authors.initials: DR
authors.lastname: Lloyd
authors.forename: Jerry B
authors.initials: JB
authors.lastname: Richards
mesh_terms: D000818:Animals; D003042:Cocaine / Q000008:administration & dosage / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D008124:Locomotion; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D012646:Self Administration; D014867:Water / Q000008:administration & dosage*
chemical_list: D014867:Water; D003042:Cocaine