title: Cocaine self-administration in social dyads using custom-built operant conditioning chambers.
abstract: BACKGROUND
  Traditionally, the analysis of intravenous drug self-administration is limited to conditions in which subjects are tested in isolation. This limits the translational appeal of these studies because drug use in humans often occurs in the presence of others.
  
  
  METHODS
  We used custom-built operant conditioning chambers that allowed social dyads visual, olfactory, auditory, and limited tactile contact while concurrently self-administering cocaine. Male rats were trained to respond according to a fixed interval schedule of reinforcement (with a limited hold) in order to determine if patterns of cocaine (0.75mg/kg/infusion) self-administration became more similar over time in social pairs. Cocaine self-administration was tested across five days according to a 10-min fixed interval schedule (with a 5-min limited hold). Quarter-life values (time at which 25% of responses were emitted per interval) were analyzed using intraclass correlations.
  
  
  RESULTS
  The total number of reinforcers obtained did not vary across the five days of testing; however, quarter-life values became progressively more similar between individuals within the social dyads.
  
  
  METHODS
  Standard operant conditioning chambers are unable to assess responding in multiple animals due to their small size, the need to prevent subjects from responding on the lever of their partner, and the need to prevent infusion lines from entangling. By using custom-built social operant conditioning chambers, we assessed the effects of social contact on cocaine self-administration.
  
  
  CONCLUSIONS
  Social operant conditioning chambers can be used as a preclinical method to examine social influences on drug self-administration under conditions that approximate human substance use.
authors.affiliation: Department of Psychology, Davidson College, USA.
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Lacy
authors.affiliation: Department of Psychology, Davidson College, USA.
authors.forename: Justin C
authors.initials: JC
authors.lastname: Strickland
authors.affiliation: Department of Psychology, Davidson College, USA; Program in Neuroscience, Davidson College, USA. Electronic address: masmith@davidson.edu.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Smith
mesh_terms: D061605:Administration, Intravenous / Q000295:instrumentation / Q000379:methods; D000818:Animals; D002408:Catheters, Indwelling; D003042:Cocaine / Q000008:administration & dosage*; D003216:Conditioning, Operant / Q000187:drug effects*; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage*; D006799:Housing, Animal; D008297:Male; D020318:Rats, Long-Evans; D012055:Reinforcement Schedule; D012646:Self Administration / Q000295:instrumentation* / Q000379:methods; D012919:Social Behavior
chemical_list: D018765:Dopamine Uptake Inhibitors; D003042:Cocaine
keywords: Cocaine; Fixed interval; Operant; Self-administration; Social
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