Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience-MHeNS, European Graduate School of Neuroscience-EURON, Maastricht University, Maastricht, The Netherlands.
Behav Brain Res. 2012 Jul 1;232(2):323-34. doi: 10.1016/j.bbr.2012.03.023. Epub 2012 Mar 28.
The object recognition task (ORT) allows assessing learning and memory processes in rodents. In this study, two areas in which knowledge about the ORT could be extended were addressed; i.e. generality to species and strains, and intervening variables including housing and estrous cycle. Regarding generality to species and strains, the ORT performance of golden hamsters was assessed. The hamsters showed sufficient exploration times, object recognition performance, and a retention-interval dependent decline similar to rats and mice. Subsequently, we tested three mouse strains which have not been described before in the ORT; i.e. OF1, NMRI, and SJL mice. OF1 and NMRI strains performed equally well, whereas the SJL strain showed low exploration times and no memory retention. Therefore, the SJL strain is unsuited for ORT experiments using a 1h retention interval and a fixed (3 min) trial duration. Furthermore, the sensitivity to a pharmacological memory deficit model (scopolamine) was tested in three rat strains. Each strain showed a dose dependent relationship, but the least effective dose of scopolamine differed among the three strains, the effect being greater in the order of Wistar, Long-Evans, Hooded Lister rats. Finally, to investigate potential intervening variables in the ORT, the effects of housing conditions and estrous cycle were investigated with rats. Single housing resulted in absolute higher performance than social housing. Furthermore, females in pro-estrus/estrus showed better performance compared to females in met-estrus/di-estrus. Taken together, object recognition appears to be a common ability of rodent species, but different strains have different memory capacities and sensitivities to scopolamine, individual housing leads to higher performance, and performance of females is dependent on the estrous cycle phase. Thus, rodent species, strain, housing, and estrous cycle should be taken into consideration in ORT studies.
物体识别任务（ORT）可用于评估啮齿动物的学习和记忆过程。在这项研究中，我们扩展了两个可以进一步了解 ORT 的领域，即物种和品系的通用性，以及包括饲养和发情周期在内的干预变量。关于物种和品系的通用性，评估了金黄仓鼠的 ORT 表现。仓鼠表现出足够的探索时间、物体识别性能和与大鼠和小鼠相似的保留间隔依赖性下降。随后，我们测试了三种以前在 ORT 中未描述过的小鼠品系，即 OF1、NMRI 和 SJL 小鼠。OF1 和 NMRI 品系表现相当，而 SJL 品系表现出低探索时间和无记忆保留。因此，SJL 品系不适合使用 1 小时保留间隔和固定（3 分钟）试验持续时间进行 ORT 实验。此外，还在三种大鼠品系中测试了对药理学记忆缺陷模型（东莨菪碱）的敏感性。每种品系均显示出剂量依赖性关系，但三种品系中东莨菪碱的最低有效剂量不同，其效果按 Wistar、Long-Evans、 Hooded Lister 大鼠的顺序递增。最后，为了研究 ORT 中的潜在干预变量，研究了大鼠的饲养条件和发情周期的影响。独居导致的表现绝对高于群居。此外，发情前期/发情期的雌性比发情中期/发情后期的雌性表现更好。总之，物体识别似乎是啮齿动物物种的共同能力，但不同的品系对东莨菪碱的记忆能力和敏感性不同，独居会导致更高的表现，而雌性的表现取决于发情周期阶段。因此，在 ORT 研究中应考虑啮齿动物的物种、品系、饲养和发情周期。
