De Leonibus Elvira, Oliverio Alberto, Mele Andrea
Dipartimento di Genetica e Biologia Molecolare, Università di Roma La Sapienza, 00185 Rome, Italy.
Learn Mem. 2005 Sep-Oct;12(5):491-503. doi: 10.1101/lm.94805. Epub 2005 Sep 15.
There is now accumulating evidence that the striatal complex in its two major components, the dorsal striatum and the nucleus accumbens, contributes to spatial memory. However, the possibility that different striatal subregions might modulate specific aspects of spatial navigation has not been completely elucidated. Therefore, in this study, two different learning procedures were used to determine whether the two striatal components could be distinguished on the basis of their involvement in spatial learning using different frames of reference: allocentric and egocentric. The task used involved the detection of a spatial change in the configuration of four objects placed in an arena, after the mice had had the opportunity to experience the objects in a constant position for three previous sessions. In the first part of the study we investigated whether changes in the place where the animals were introduced into the arena during habituation and testing could induce a preferential use of an egocentric or an allocentric frame of reference. In the second part of the study we performed focal injections of the N-methyl-d-aspartate (NMDA) receptors' antagonist, AP-5, within the two subregions immediately after training. The results indicate that using the two behavioral procedures, the animals rely on an egocentric and an allocentric spatial frame of reference. Furthermore, they demonstrate that AP-5 (37.5, 75, and 150 ng/side) injections into the dorsal striatum selectively impaired consolidation of spatial information in the egocentric but not in the allocentric procedure. Intra-accumbens AP-5 administration, instead, impaired animals trained using both procedures.
目前越来越多的证据表明，纹状体复合体的两个主要组成部分，即背侧纹状体和伏隔核，对空间记忆有贡献。然而，不同纹状体亚区可能调节空间导航特定方面的可能性尚未完全阐明。因此，在本研究中，使用了两种不同的学习程序来确定这两个纹状体组成部分是否可以根据它们在使用不同参照系（心向参照系和自我参照系）进行空间学习中的参与情况来区分。所使用的任务涉及在小鼠有机会在前三个实验环节中体验四个放置在竞技场中的物体处于恒定位置之后，检测这些物体配置的空间变化。在研究的第一部分，我们调查了在习惯化和测试过程中动物被引入竞技场的位置变化是否会导致优先使用自我参照系或心向参照系。在研究的第二部分，我们在训练后立即在两个亚区内局部注射N - 甲基 - D - 天冬氨酸（NMDA）受体拮抗剂AP - 5。结果表明，使用这两种行为程序时，动物依赖自我参照系和心向参照系的空间参照系。此外，结果表明，向背侧纹状体内注射AP - 5（37.5、75和150 ng/侧）会选择性地损害自我参照系程序中空间信息的巩固，但不会损害心向参照系程序中的空间信息巩固。相反，向伏隔核内注射AP - 5会损害使用这两种程序训练的动物。
