Effects of different social experiences on emotional state in mice

Abstract

A comprehensive understanding of animals’ emotions can be achieved by combining cognitive, behavioural, and physiological measures. Applying such a multi-method approach, we here examined the emotional state of mice after they had made one of three different social experiences: either a mildly “adverse”, a “beneficial”, or a “neutral” experience. Using a recently established touchscreen paradigm, cognitive judgement bias was assessed twice, once before and once after the respective experience. Anxiety-like behaviour was examined using a standardised battery of behavioural tests and faecal corticosterone metabolite concentrations were measured. Surprisingly, only minor effects of the social experiences on the animals’ cognitive judgement bias and no effects on anxiety-like behaviour and corticosterone metabolite levels were found. It might be speculated that the experiences provided were not strong enough to exert the expected impact on the animals’ emotional state. Alternatively, the intensive training procedure necessary for cognitive judgement bias testing might have had a cognitive enrichment effect, potentially countering external influences. While further investigations are required to ascertain the specific causes underlying our findings, the present study adds essential empirical data to the so far scarce amount of studies combining cognitive, behavioural, and physiological measures of emotional state in mice.

Once an Optimist, Always an Optimist? Studying Cognitive Judgment Bias in Mice

“…The reason for this is not clear but might be due to lower response accuracy towards this cue. Mice had more difficulties in learning the correct response towards the negative than to the positive reference cue, probably resulting in lower accuracy in our paradigm (Krakenberg et al, 2019a;Krakenberg et al, 2019b;Krakenberg et al, 2020).…”

“…The paradigm applied here was the same as described previously in Krakenberg et al (2020) with minor modifications in the discrimination training (Table S1 in Supplementary Material).…”

“…Table S1: Discrimination training steps after Krakenberg et al (2020) with modifications. Discrimination training consisted of six steps.…”

Using touchscreen-delivered cognitive assessments to address the principles of the 3Rs in behavioral sciences

“…A recently characterized touchscreen cognitive judgement bias task also avoids footshock administration. Tasks evaluating affective state bias in decision making often involve the administration of footshocks to represent negative emotional valance 94,95 , however, the touchscreen variant instead uses a brief time-out period under inverted illumination conditions to achieve the same effect 96,97 .…”

“…Examples of these affective state-related construct-focused tasks include the touchscreen implementations of the progressive ratio (PR) schedule for the evaluation of motivation 129,130 , the probabilistic reversal learning (PRL) task for the evaluation of negative feedback sensitivity 127,131,132 the affective/cognitive bias task 96,97,128 and the PRT 54 . The development of these tasks is particularly important from a 3Rs perspective because the assessment of mood-related constructs in experimental animals often requires stress induction 30,32 , including in widely used assays such as the tail suspension test (TST) and the FST 133 .…”