Rostron Claire L, Gaeta Victoria, Brace Louise R, Dommett Eleanor J
Dept Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK.
Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Addison House, Guy's Campus, London, SE1 1UL, UK.
BMC Res Notes. 2017 Oct 30;10(1):525. doi: 10.1186/s13104-017-2857-5.
The spontaneously hypertensive rat is thought to show good validity as a model of attention deficit hyperactivity disorder, in part because of impaired delayed reinforcement behaviour, corresponding to the dynamic developmental theory of the disorder. However, some previous studies may have been confounded use of fluid reward. Therefore, the objective of this study was to assess the spontaneously hypertensive rat and two comparison strains (Wistar and Wistar Kyoto) using a non-delayed food reinforcement paradigm in an attempt to advance knowledge of basic learnt behaviour in this strain, without potentially confounding reward sensitivity, which could impact on motivation to learn. Rats were trained on a fixed ratio 1 two choice discrimination schedule, extinction, reacquisition and reversal. We also tested non-reinforced spontaneous alternation to facilitate data interpretation.
The spontaneously hypertensive rat displayed slower shaping and reduced on task activity during task acquisition, contrasting with previous results which indicate either enhanced responding and an impairment only when a delay is used; we suggest several reasons for this. In line with previous work, the same strain exhibited poor extinguishing of behaviour but were not impaired to the same extent on reversal of the discrimination. Finally, non-reinforced alternations on a Y-maze were also reduced in the spontaneously hypertensive rat.
In sum, the spontaneously hypertensive rat appear to show poor response inhibition in reinforced and non-reinforced contexts. However, impaired response inhibition was reduced during reversal when an opposite response produced food reward alongside presentation of the conditioned stimulus. We discuss the possibility of enhanced attribution of incentive salience to cues in this strain and highlight several points of caution for researchers conducting behavioural assessments using the spontaneously hypertensive rat and their associated comparison strains.
自发性高血压大鼠被认为是注意力缺陷多动障碍的良好模型，部分原因是其延迟强化行为受损，这与该疾病的动态发展理论相符。然而，之前的一些研究可能因使用液体奖励而受到干扰。因此，本研究的目的是使用非延迟食物强化范式评估自发性高血压大鼠及两种对照品系（Wistar和Wistar Kyoto），以增进对该品系基本学习行为的了解，同时避免可能影响学习动机的奖励敏感性干扰。大鼠接受固定比率1的二选一辨别训练、消退训练、重新训练和逆转训练。我们还测试了非强化自发交替行为以方便数据解读。
自发性高血压大鼠在任务习得过程中表现出较慢的塑形过程和较低的任务活动度，这与之前的结果形成对比，之前的结果表明要么反应增强，要么仅在使用延迟时出现损伤；我们提出了几个原因。与之前的研究一致，同一品系的大鼠行为消退较差，但在辨别逆转时受损程度不同。最后，自发性高血压大鼠在Y迷宫上的非强化交替行为也减少了。
总之，自发性高血压大鼠在强化和非强化情境中似乎表现出较差的反应抑制能力。然而，当相反反应在条件刺激呈现的同时产生食物奖励时，逆转过程中反应抑制受损程度有所降低。我们讨论了该品系中线索的激励显著性归因增强的可能性，并强调了研究人员在使用自发性高血压大鼠及其相关对照品系进行行为评估时需要注意的几点。
