title: Chronic psychosocial stress makes rats more 'pessimistic' in the ambiguous-cue interpretation paradigm.
abstract: Human decisions are often biased by emotions. Stressed and depressed individuals tend to make negative, pessimistic judgements while those in positive affective states are often more optimistic. Chronic psychosocial stress has previously been shown to induce a spectrum of behavioural and physiological changes in rats that are considered the correlates of depressive symptoms in humans. In this study, we investigate whether chronic social defeat makes animals more 'pessimistic'. To measure the changes in cognitive judgement bias, we applied the ambiguous-cue interpretation paradigm. In the operant boxes, the rats were trained to press one lever in response to one tone to receive a reward and to press another lever in response to a different tone to avoid punishment. Cognitive bias was tested by measuring the pattern of animals' responses to a tone of intermediate frequency (ambiguous-cue). To induce chronic psychosocial stress, we subjected the animals to daily social defeat in the resident-intruder paradigm for 3 weeks. We report that chronic psychosocial stress makes rats more pessimistic.
authors.affiliation: Cognitive Affective 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: Justyna
authors.initials: J
authors.lastname: Papciak
authors.forename: Piotr
authors.initials: P
authors.lastname: Popik
authors.forename: Eberhard
authors.initials: E
authors.lastname: Fuchs
authors.forename: Rafal
authors.initials: R
authors.lastname: Rygula
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001290:Attitude; D002908:Chronic Disease; D003216:Conditioning, Operant; D003463:Cues; D004192:Discrimination, Psychological; D004597:Electroshock; D007600:Judgment; D008297:Male; D011581:Psychological Tests; D011678:Punishment; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012201:Reward; D012930:Social Dominance; D013315:Stress, Psychological / Q000523:psychology*
keywords: Ambiguous cue; Depression; Pessimism; Rat; Social Defeat; Stress