Wallace Douglas G, Whishaw Ian Q
Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, T1K 3M4 Canada.
Eur J Neurosci. 2003 Aug;18(3):513-23. doi: 10.1046/j.1460-9568.2003.02772.x.
Dead reckoning, a form of navigation used to locate a present position and to return to a starting position, is used by rats to return to their home base. The present experiment examined whether dead reckoning is displayed by rats during their first exploratory excursions in a novel environment and also examined whether the behaviour requires the integrity of the cells of the hippocampus. Experimental rats, those with NMDA (N-methyl d-aspartate) lesions of Ammon's horn and the dentate gyrus, and control rats could leave a cage to explore a large circular table under light and dark conditions. Home base behaviour, use of olfactory cues, and thigmotaxic- based navigation were evaluated. Temporal, topographical and kinematic analyses were conducted on the first three exploratory excursions that extended at least halfway across the table. Groups did not differ in numbers of exits from the home base, lingering near the home base, distance travelled, or the use of surface cues as might be exemplified by thigmotaxic and olfactory behaviour. Temporal, topographical and kinematic reconstructions of homing behaviour, however, indicated that control rats, but not hippocampal rats, made direct high velocity return trips to the home base in both the light and the dark. Peak velocity of the trips occurred at the trip midpoint, independent of trip distance, suggesting the movements were preplanned. These results are discussed in relation to the ideas that dead reckoning is used in the homing of exploring rats and that this form of navigation involves the hippocampus.
航位推测法是一种用于确定当前位置并返回起始位置的导航方式，大鼠会用它返回自己的巢穴。本实验研究了大鼠在新环境中的首次探索行程中是否会表现出航位推测行为，还研究了这种行为是否需要海马体细胞的完整性。实验大鼠、患有海马角和齿状回NMDA（N-甲基-D-天冬氨酸）损伤的大鼠以及对照大鼠可以离开笼子，在明亮和黑暗条件下探索一个大圆桌。评估了归巢行为、嗅觉线索的使用以及基于趋触性的导航。对至少延伸到桌子一半距离的前三次探索行程进行了时间、地形和运动学分析。各组在离开巢穴的次数、在巢穴附近逗留的时间、行进的距离或趋触性和嗅觉行为所体现的表面线索的使用方面没有差异。然而，归巢行为的时间、地形和运动学重建表明，对照大鼠而非海马体损伤大鼠在明亮和黑暗环境中都能直接高速返回巢穴。行程的峰值速度出现在行程中点，与行程距离无关，这表明这些运动是预先计划好的。结合探索大鼠归巢时使用航位推测法以及这种导航形式涉及海马体的观点对这些结果进行了讨论。
