Kesner Raymond P, Kirk Ryan A, Yu Zhenghui, Polansky Caitlin, Musso Nick D
University of Utah, Department of Psychology, USA.
Neurobiol Learn Mem. 2016 Mar;129:29-37. doi: 10.1016/j.nlm.2015.08.010. Epub 2015 Aug 28.
In order to examine the role of the dorsal dentate gyrus (dDG) in slope (vertical space) recognition and possible pattern separation, various slope (vertical space) degrees were used in a novel exploratory paradigm to measure novelty detection for changes in slope (vertical space) recognition memory and slope memory pattern separation in Experiment 1. The results of the experiment indicate that control rats displayed a slope recognition memory function with a pattern separation process for slope memory that is dependent upon the magnitude of change in slope between study and test phases. In contrast, the dDG lesioned rats displayed an impairment in slope recognition memory, though because there was no significant interaction between the two groups and slope memory, a reliable pattern separation impairment for slope could not be firmly established in the DG lesioned rats. In Experiment 2, in order to determine whether, the dDG plays a role in shades of grey spatial context recognition and possible pattern separation, shades of grey were used in a novel exploratory paradigm to measure novelty detection for changes in the shades of grey context environment. The results of the experiment indicate that control rats displayed a shades of grey-context pattern separation effect across levels of separation of context (shades of grey). In contrast, the DG lesioned rats displayed a significant interaction between the two groups and levels of shades of grey suggesting impairment in a pattern separation function for levels of shades of grey. In Experiment 3 in order to determine whether the dorsal CA3 (dCA3) plays a role in object pattern completion, a new task requiring less training and using a choice that was based on choosing the correct set of objects on a two-choice discrimination task was used. The results indicated that control rats displayed a pattern completion function based on the availability of one, two, three or four cues. In contrast, the dCA3 lesioned rats displayed a significant interaction between the two groups and the number of available objects suggesting impairment in a pattern completion function for object cues.
为了研究齿状回背侧（dDG）在坡度（垂直空间）识别及可能的模式分离中的作用，在实验1中，采用了一种新颖的探索性范式，利用不同的坡度（垂直空间）度数来测量坡度（垂直空间）识别记忆变化和坡度记忆模式分离中的新奇性检测。实验结果表明，对照大鼠表现出坡度识别记忆功能，且坡度记忆存在模式分离过程，该过程取决于学习阶段和测试阶段之间坡度变化的幅度。相比之下，dDG损伤的大鼠在坡度识别记忆方面表现出损伤，不过由于两组与坡度记忆之间没有显著的交互作用，因此无法在DG损伤的大鼠中确切证实存在可靠的坡度模式分离损伤。在实验2中，为了确定dDG是否在灰度空间背景识别及可能的模式分离中发挥作用，采用了一种新颖的探索性范式，利用灰度来测量灰度背景环境变化中的新奇性检测。实验结果表明，对照大鼠在不同程度的背景分离（灰度）水平上表现出灰度背景模式分离效应。相比之下，DG损伤的大鼠在两组与灰度水平之间表现出显著的交互作用，这表明在灰度水平的模式分离功能方面存在损伤。在实验3中，为了确定背侧CA3（dCA3）是否在物体模式完成中发挥作用，使用了一项新任务，该任务所需训练较少，且在二选一辨别任务中基于选择正确的物体组进行选择。结果表明，对照大鼠基于一个、两个、三个或四个线索的可用性表现出模式完成功能。相比之下，dCA3损伤的大鼠在两组与可用物体数量之间表现出显著的交互作用，这表明在物体线索的模式完成功能方面存在损伤。
