Laboratoire d'Ethologie Expérimentale et Comparée UR 4443 (LEEC), Université Sorbonne Paris Nord, F-93430, Villetaneuse, France; Laboratory of Ethology, Ecology and Evolution of Social Insects, Department of Experimental Psychology, University of Sao Paulo, São Paulo, Brazil.
Laboratoire d'Ethologie Expérimentale et Comparée UR 4443 (LEEC), Université Sorbonne Paris Nord, F-93430, Villetaneuse, France.
Behav Brain Res. 2021 Jun 11;407:113262. doi: 10.1016/j.bbr.2021.113262. Epub 2021 Mar 26.
Judgment bias tests have become an important tool in the assessment of animals' affective states. Subjects are first trained to discriminate between two cues associated with a positive and a less-positive outcome. After successful training, they are confronted with an ambiguous cue, and responses are used for judgment bias assessment. In spatial settings, ambiguous cue presentation is typically linked with novelty, i.e. to yet unexplored areas or areas to which the animal has a low degree of habituation. We hypothesized that in such settings, responses to ambiguity might be biased by the animals' perception of novelty. We conducted judgment bias tests in mound-building mice phenotyped for their exploration tendency. After subjects had learned to distinguish between the positively and less-positively rewarded arms of a maze, a new ambiguous middle-arm was introduced. During the first test trial, more exploratory, less neophobic individuals displayed higher bidirectional locomotion in the ambiguous arm, indicating intensive exploration. Although this resulted in longer latencies to the reward in more exploratory animals, we conclude that this did not reflect a 'more pessimistic judgment of ambiguity'. Indeed, during the following two trials, with increasing habituation to the ambiguous arm, the direction of the association was inversed compared to the first trial, as more exploratory individuals showed relatively shorter approach latencies. We suggest that in spatial test settings associating the ambiguous cue to novel areas, results can be confounded by subjects' personality-dependent motivational conflict between exploration and reaching the reward. Findings obtained under such conditions should be interpreted with care.
判断偏差测试已成为评估动物情感状态的重要工具。首先，对动物进行训练，使其区分与正性和次正性结果相关的两种线索。成功训练后，动物会面临一个模糊线索，然后根据其反应进行判断偏差评估。在空间环境中，模糊线索的呈现通常与新奇性相关联，即与未探索的区域或动物对其适应程度较低的区域相关联。我们假设，在这种环境中，动物对模糊性的反应可能受到其对新奇性的感知的影响。我们对表现出不同探索倾向的筑丘小鼠进行了判断偏差测试。在动物学会区分迷宫中具有正性和次正性奖励的臂之后，引入了一个新的中间模糊臂。在第一次测试试验中，更具探索性、较少新奇恐惧症的个体在模糊臂中表现出更高的双向运动，表明其进行了更深入的探索。尽管这导致更具探索性的动物在奖励上的潜伏期更长，但我们得出的结论是，这并不反映出对模糊性的“更悲观的判断”。实际上，在接下来的两次试验中，随着对模糊臂的适应程度增加，与第一次试验相比，这种关联的方向发生了反转，因为更具探索性的个体表现出相对较短的接近潜伏期。我们认为，在空间测试环境中，将模糊线索与新区域相关联时，由于个体之间的探索和获得奖励之间的动机冲突是由个性决定的，因此结果可能会受到混淆。在这种条件下获得的结果应谨慎解释。
