title: Motivational assessment of mice using the touchscreen operant testing system: effects of dopaminergic drugs.
abstract: BACKGROUND
  Touchscreens are widely used to examine rodent cognition. Current paradigms require animals to view stimuli and nose poke at an appropriate touchscreen location. After responding, there is little screen interaction and, as infra-red touchscreens eliminate the need for physical contact, minimal somatosensory feedback. It is therefore unclear if touchscreens can support the vigorous, repetitive responding required in paradigms like progressive ratio (PR) for assessing motivation and effort-related choice (ERC) for assessing decision-making.
  
  
  OBJECTIVE
  This study aims to adapt and validate PR and ERC for the rodent touchscreen.
  
  
  METHODS
  Male C57Bl/6 mice were trained until responding on PR stabilised. Amphetamine, sulpiride and raclopride were administered via the intraperitoneal route to modify performance. Mice were transferred to ERC and paradigm parameters adjusted to demonstrate behavioural modification. ERC reward preference was assessed by home cage choice analysis.
  
  
  RESULTS
  PR performance stabilised within seven sessions. Amphetamine (1 mg/kg) increased and raclopride (0.3 mg/kg) decreased performance by 63 and 28 %, respectively, with a 20-min injection-test interval. Sulpiride (50 mg/kg) decreased performance by 19 % following a 40-min injection-test interval. Increasing ERC operant requirements shifted responding from the operant response-dependent preferred reward towards the freely available alternative.
  
  
  CONCLUSIONS
  Vigorous, repetitive responding is sustainable in touchscreen PR and ERC and task validation mirrors non-touchscreen versions. Thus, motivation and reward-related decision-making can be measured directly with touchscreens and can be evaluated prior to cognitive testing in the same apparatus to avoid confounding by motivational factors.
authors.affiliation: Department of Psychology and MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK. cjh201@cam.ac.uk.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Heath
authors.affiliation: Department of Psychology and MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Bussey
authors.affiliation: Department of Psychology and MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Saksida
mesh_terms: D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D002755:Choice Behavior / Q000187:drug effects*; D003071:Cognition / Q000187:drug effects*; D003216:Conditioning, Operant / Q000187:drug effects*; D015259:Dopamine Agents / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009042:Motivation / Q000187:drug effects*; D020891:Raclopride / Q000494:pharmacology; D012201:Reward; D013469:Sulpiride / Q000494:pharmacology
chemical_list: D015259:Dopamine Agents; D020891:Raclopride; D013469:Sulpiride; D000661:Amphetamine
keywords: Dopamine; Effort-related choice; Motivation; Progressive ratio; Rodent; Touchscreen