Background

Cognitive impairment is a distinguishing feature of many neurodegenerative diseases. The intra-dimensional (ID) extra-dimensional (ED) attentional set shift task is part of a clinical battery of tests used to evaluate executive function in Huntington’s and Alzheimer’s disease patients. The IDED task, however, has not translated well to pre-clinical rodent models of neurological disease.

New method

The ability to perform executive tasks coupled with a long lifespan makes sheep (Ovis aries) an ideal species for modelling cognitive decline in progressive neurodegenerative conditions. We describe the methodology for testing the performance of sheep in the IDED task using a semi-automated system in which visual stimuli are presented as coloured letters on computer screens.

Results

During each stage of IDED testing, all sheep (n = 12) learned successfully to discriminate between different colours and letters. Sheep were quick to learn the rules of acquisition at each stage. They required significantly more trials to reach criterion (p < 0.05) and made more errors (p < 0.05) following stimulus reversal, with the exception of the ED shift (p > 0.05).

Comparison with existing method(s)

Previous research shows that sheep can perform IDED set shifting in a walk-through maze using solid objects with two changeable dimensions (colour and shape) as the stimuli. Presenting the stimuli on computer screens provides better validity, greater task flexibility and higher throughput than the walk-through maze.

Conclusion

All sheep completed each stage of the task, with a range of abilities expected in an outbred population. The IDED task described is ideally suited as a quantifiable and clinically translatable measure of executive function in sheep.

中文翻译：

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在半自动操作系统中使用视觉刺激测量绵羊（Ovis aries）的执行功能

背景

认知障碍是许多神经退行性疾病的显着特征。维度内（ID）维度外（ED）注意设定移位任务是临床测试的一部分，该测试用于评估亨廷顿病和阿尔茨海默氏病患者的执行功能。然而，IDED的任务尚未很好地转化为神经疾病的临床前啮齿动物模型。

新方法

执行任务的能力以及较长的使用寿命使绵羊（Ovis aries）成为模拟进行性神经退行性疾病中认知能力下降的理想物种。我们描述了一种使用半自动化系统在IDED任务中测试绵羊性能的方法，在该系统中，视觉刺激在计算机屏幕上显示为彩色字母。

结果

在IDED测试的每个阶段，所有绵羊（n = 12）都成功地学会了区分不同的颜色和字母。绵羊很快就能在每个阶段学习习得规则。他们需要更多的试验才能达到标准（p <0.05），并在刺激逆转后产生更多的错误（p <0.05），但ED移位（p> 0.05）除外。

与现有方法的比较

先前的研究表明，绵羊可以使用具有两个可变尺寸（颜色和形状）的固体对象作为刺激，在漫游迷宫中执行IDED设置移位。与漫游迷宫相比，在计算机屏幕上显示刺激可以提供更好的有效性，更大的任务灵活性和更高的吞吐量。

结论

所有绵羊都完成了该任务的每个阶段，并且在远交种群中具有各种能力。所描述的IDED任务非常适合作为绵羊执行功能的量化和临床翻译测量。