title: Investigating the psychopharmacology of cognitive affective bias in rats using an affective tone discrimination task.
abstract: BACKGROUND
  Affective states are known to influence behaviour in humans resulting in cognitive affective biases, which may play an important role in the development and treatment of mood disorders. Similar biases have recently been shown in animals, including the rat, providing an opportunity to investigate these processes in non-human species.
  
  
  OBJECTIVE
  This study sought to investigate the psychopharmacology of cognitive affective bias in rats using systemic treatments with anxiolytic (diazepam) and antidepressant drugs (reboxetine or fluoxetine).
  
  
  METHODS
  Lister hooded rats were trained to discriminate two distinct tones and respond on the appropriate lever to either obtain reward (food) or avoid punishment (mild foot shock). Cognitive affective bias, following acute or chronic drug treatment, was investigated using test sessions where both reference tones and intermediate ambiguous tones were included.
  
  
  RESULTS
  Rats exhibited a negative judgement bias under vehicle conditions which was not significantly attenuated by any of the acute drug treatments, diazepam (0.3, 1.0 mg/kg), reboxetine (0.3-3.0 mg/kg) or fluoxetine 0.1-1.0 mg/kg). Acute reboxetine induced a significant and dose-dependent decrease in the anticipation of reward. Chronic treatment with fluoxetine tended to reduce the negative bias observed in the rats after 1 week of treatment although no significant main effect of treatment was observed.
  
  
  CONCLUSIONS
  The results from these initial psychopharmacological studies show that drug treatments can differentially affect motivation to respond to cues associated with reward versus punishment. Our data also suggest that cognitive affective bias, quantified using this method, may be sensitive to chronic but not acute antidepressant treatment.
authors.affiliation: School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD, UK.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Anderson
authors.forename: Marcus R
authors.initials: MR
authors.lastname: Munafò
authors.forename: Emma S J
authors.initials: ES
authors.lastname: Robinson
mesh_terms: D000339:Affect; D000818:Animals; D014151:Anti-Anxiety Agents / Q000008:administration & dosage / Q000494:pharmacology; D000928:Antidepressive Agents / Q000008:administration & dosage / Q000494:pharmacology; D015982:Bias; D003071:Cognition; D003463:Cues; D003975:Diazepam / Q000008:administration & dosage / Q000494:pharmacology*; D004193:Discrimination Learning / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005473:Fluoxetine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009025:Morpholines / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D000077593:Reboxetine; D012201:Reward
chemical_list: D014151:Anti-Anxiety Agents; D000928:Antidepressive Agents; D009025:Morpholines; D005473:Fluoxetine; D000077593:Reboxetine; D003975:Diazepam