Urbach Anja, Robakiewicz Ita, Baum Eileen, Kaczmarek Leszek, Witte Otto W, Filipkowski Robert K
Hans Berger Department of Neurology, Jena University Hospital, Jena, Germany.
Behav Neurosci. 2013 Feb;127(1):1-8. doi: 10.1037/a0031222. Epub 2012 Dec 17.
There is a broad discussion concerning the function of new neurons in the adult brain. An increasingly accepted hypothesis proposes their crucial role in spatial learning. In this work, however, we demonstrate adult cyclin D2 knockout (cD2 KO) mice, which lack adult hippocampal neurogenesis, are able to learn a spatial version of the Barnes maze. Similar to wild type (WT) controls, these mutant mice exhibited several indicators of learning during 6 days of training: successively shorter latency and distance, higher speed, and decreasing number of errors. WT and cD2 KO mice showed improved search strategies, which became increasingly spatial. During probe Trial 1, mutant mice attained the highest significant number of nose-pokes at the former target hole compared with all the other holes. Both WT and cD2 KO mice covered shorter distances during probe Trial 2, whereas the mutant mice showed higher speed. We also discuss the possibility that some of the observed differences displayed by cD2 KO mice during training and at the probe trials-for example, longer mean distance and more errors-are associated with a smaller hippocampal formation. Our results suggest that adult brain neurogenesis is not obligatory for learning the Barnes maze.
关于成体大脑中新神经元的功能存在广泛讨论。一个越来越被接受的假说是它们在空间学习中起关键作用。然而，在这项研究中，我们证明了缺乏成体海马神经发生的成年细胞周期蛋白D2基因敲除（cD2 KO）小鼠能够学会巴恩斯迷宫的空间版本。与野生型（WT）对照相似，这些突变小鼠在6天的训练过程中表现出几个学习指标：潜伏期和路程相继缩短、速度提高以及错误数量减少。WT和cD2 KO小鼠都表现出改进的搜索策略，且越来越具有空间性。在探索试验1中，与所有其他洞相比，突变小鼠在前目标洞处获得的显著鼻触次数最多。在探索试验2中，WT和cD2 KO小鼠走过的路程都较短，而突变小鼠速度更快。我们还讨论了cD2 KO小鼠在训练和探索试验期间表现出的一些观察到的差异——例如，平均路程更长和错误更多——可能与较小的海马结构有关的可能性。我们的结果表明，成体脑内神经发生对于学习巴恩斯迷宫并非必不可少。
