Institute of Cell Biology and Neurosciences, National Scientific and Technical Research Council-University of Buenos Aires, Autonomous City of Buenos Aires, Argentina; Laboratory of Experimental Animals, Faculty of Veterinary Sciences, National University of La Plata, La Plata, Argentina.
Department of Integrative Biology, University of Guelph, Guelph, Canada.
Physiol Behav. 2021 Sep 1;238:113465. doi: 10.1016/j.physbeh.2021.113465. Epub 2021 May 21.
In humans, affective states can bias responses to ambiguous information: a phenomenon termed judgment bias (JB). Judgment biases have great potential for assessing affective states in animals, in both animal welfare and biomedical research. New animal JB tasks require construct validation, but for laboratory mice (Mus musculus), the most common research vertebrate, a valid JB task has proved elusive. Here (Experiment 1), we demonstrate construct validity for a novel mouse JB test: an olfactory Go/Go task in which subjects dig for high- or low-value food rewards. In C57BL/6 and Balb/c mice faced with ambiguous cues, latencies to dig were sensitive to high/low welfare housing: environmentally-enriched animals responded with relative 'optimism' through shorter latencies. Illustrating the versatility of this validated JB task across different fields of research, it further allowed us to test hypotheses about the mood-altering effects of cancer in male and female nude mice (Experiment 2). Males, although not females, treated ambiguous cues as intermediate; and males bearing subcutaneous lung adenocarcinomas also responded more pessimistically to these than did healthy controls. To our knowledge, this is the first evidence of a valid mouse JB task, and the first demonstration of pessimism in tumor-bearing animals. This task still needs to be refined to improve its sensitivity. However, it has great potential for investigating mouse welfare, the links between affective state and disease, depression-like states in animals, and hypotheses regarding the neurobiological mechanisms that underlie affect-mediated biases in judgment.
在人类中，情感状态可以影响对模棱两可信息的反应：这一现象被称为判断偏差（JB）。判断偏差在评估动物的情感状态方面具有很大的潜力，无论是在动物福利还是在生物医学研究中。新的动物 JB 任务需要进行结构验证，但对于实验室小鼠（Mus musculus），即最常见的研究脊椎动物，一种有效的 JB 任务一直难以实现。在这里（实验 1），我们展示了一种新的小鼠 JB 测试的结构有效性：一种嗅觉 Go/Go 任务，其中受试者挖掘高值或低值食物奖励。在面临模棱两可线索的 C57BL/6 和 Balb/c 小鼠中，挖掘的潜伏期对高/低福利住房敏感：环境丰富的动物通过缩短潜伏期表现出相对的“乐观”。通过验证跨不同研究领域的这项通用性 JB 任务，它进一步允许我们测试关于癌症对雄性和雌性裸鼠情绪影响的假设（实验 2）。雄性，尽管不是雌性，将模棱两可的线索视为中间线索；并且患有皮下肺腺癌的雄性对这些线索的反应也比健康对照组更悲观。据我们所知，这是第一个有效的小鼠 JB 任务的证据，也是第一个在肿瘤携带动物中表现出悲观情绪的证据。这项任务仍需要进一步改进以提高其灵敏度。然而，它在研究小鼠福利、情感状态与疾病之间的联系、动物的抑郁样状态以及关于影响判断的神经生物学机制的假设方面具有很大的潜力。
