title: Dopamine induces an optimism bias in rats-Pharmacological proof for the translational validity of the ambiguous-cue interpretation test.
abstract: Recent findings have revealed that pharmacological enhancement of dopaminergic (DA) function by the administration of a dopaminergic precursor (dihydroxy-l-phenylalanine; l-DOPA) increases an optimism bias in humans. This effect is due to l-DOPA's impairment of the ability to update beliefs in response to undesirable information about the future. To test whether an 'optimistic' bias is also mediated by dopamine in animals, first, two groups of rats received either a dopaminergic precursor, l-DOPA, or a D2 receptor antagonist, haloperidol, and were subsequently tested using the ambiguous-cue interpretation (ACI) paradigm. To test whether similar effects might be observed when manipulating another neurotransmitter implicated in learning about reward and punishment, we administered the serotonin (5-HT) reuptake inhibitor escitalopram to a third group of animals and the selective and irreversible tryptophan hydroxylase inhibitor para-chlorophenylalanine (PCPA) to a fourth group. The results of our study demonstrated that prolonged (2 weeks), but not acute, l-DOPA administration induced optimistic bias in rats. Neither acute nor chronic treatment with the other tested compounds had significant effects on the cognitive judgment bias of rats. The convergence of these results with human studies suggests the translational validity of the ambiguous-cue interpretation paradigm in testing the effects of pharmacological manipulations on cognitive judgment bias (optimism/pessimism) in rats.
authors.affiliation: Affective Cognitive Neuroscience Laboratory, Department of Behavioral Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Krakow, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Kregiel
authors.affiliation: Affective Cognitive Neuroscience Laboratory, Department of Behavioral Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Krakow, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Golebiowska
authors.affiliation: Affective Cognitive Neuroscience Laboratory, Department of Behavioral Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Krakow, Poland.
authors.forename: P
authors.initials: P
authors.lastname: Popik
authors.affiliation: Affective Cognitive Neuroscience Laboratory, Department of Behavioral Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Krakow, Poland. Electronic address: rygula@gmail.com.
authors.forename: R
authors.initials: R
authors.lastname: Rygula
keywords: Ambiguous-cue; Behavior; Judgment bias; Optimism; Pessimism; Rat