A test to identify judgement bias in mice

• Published in: Behavioural brain research 2012-07, Vol.233 (1), p.45-54
• Main Authors: Boleij, Hetty, Klooster, José van’t, Lavrijsen, Marla, Kirchhoff, Susanne, Arndt, Saskia S., Ohl, Frauke
• Format: Article
• Language: English
• Subjects: 129P3 mice; Amygdala; Analysis of Variance; Animals; Anxiety; Associative learning; BALB/c mice; Behavior, Animal - physiology; Behaviour; Bias; Brain; Brain - metabolism; c-Fos protein; Chemical stimuli; Choice Behavior - physiology; Cognitive ability; Cortex; Corticosterone - blood; Discrimination Learning - physiology; Emotions; Functional Laterality; Inbreeding; Information processing; Judgement bias; Judgment - physiology; Light effects; Malus; Mice; Mice, 129 Strain; Mice, Inbred BALB C; Odor; Odorants; Odour conditioning; Proto-Oncogene Proteins c-fos - metabolism; Prunus dulcis; Reaction Time - physiology; Time Factors; vanilla
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2012.04.039

► We investigated a judgement bias test for mice. ► BALB/c mice revealed a negative judgement bias under red and white light testing conditions. ► 129P3 mice did not differentiate between the odour cues in the judgement bias test. ► c-Fos expression levels in distinct brain areas strain-dependently differed in response to the ambiguous cues. ► The here presented test might be of use to investigate emotional states via an assessment of judgement bias in mice. Emotional states are known to affect cognitive processes. For example highly anxious individuals interpret ambiguous stimuli more negatively than low anxious people, an effect called negative judgement bias. Recently, the measurement of judgement bias has been used to try and indicate emotional states in animals. In the present experiment a potential test for judgement bias in mice was examined. Mice were trained with two distinct odour cues (vanilla or apple) predicting either a palatable or an unpalatable almond piece. Subsequently their reaction to mixtures of both odours, the ambiguous stimuli, was investigated. Mice of the BALB/cJ and 129P3/J inbred mouse strains (high initial anxiety and low initial anxiety phenotypes respectively) were tested. While BALB/cJ mice showed odour association learning and showed intermediate reactions to the ambiguous cues, 129P3/J mice did not discriminate between the cues. Additionally BALB/cJ mice that were tested under more aversive white light conditions revealed a higher latency to approach the almond piece than mice tested under less aversive red light conditions. The ambiguous stimulus however was interpreted as negative under both test conditions. Brain c-Fos expression levels (a marker for neuronal activity) differed between the BALB/c/J and 129P3/J in the lateral amygdala and the prelimbic cortex, indicating differences in ambiguous information processing between the strains. The behavioural results suggest that the present judgement bias test might be used to assess emotional states in at least BALB/c mice, however further research on both behaviour and on the involved brain mechanisms is necessary to confirm this idea.