Poulter Steven L, Kosaki Yutaka, Sanderson David J, McGregor Anthony
Department of Psychology, Durham University, Durham, UK.
Department of Psychology, Waseda University, Tokyo, Japan.
Brain Neurosci Adv. 2020 Nov 17;4:2398212820972599. doi: 10.1177/2398212820972599. eCollection 2020 Jan-Dec.
We examined the role of the hippocampus and the dorsolateral striatum in the representation of environmental geometry using a spontaneous object recognition procedure. Rats were placed in a kite-shaped arena and allowed to explore two distinctive objects in each of the right-angled corners. In a different room, rats were then placed into a rectangular arena with two identical copies of one of the two objects from the exploration phase, one in each of the two adjacent right-angled corners that were separated by a long wall. Time spent exploring these two objects was recorded as a measure of recognition memory. Since both objects were in different locations with respect to the room (different between exploration and test phases) and the global geometry (also different between exploration and test phases), differential exploration of the objects must be a result of initial habituation to the object relative to its local geometric context. The results indicated an impairment in processing the local geometric features of the environment for both hippocampus and dorsolateral striatum lesioned rats compared with sham-operated controls, though a control experiment showed these rats were unimpaired in a standard object recognition task. The dorsolateral striatum has previously been implicated in egocentric route-learning, but the results indicate an unexpected role for the dorsolateral striatum in processing the spatial layout of the environment. The results provide the first evidence that lesions to the hippocampus and dorsolateral striatum impair spontaneous encoding of local environmental geometric features.
我们使用自发物体识别程序研究了海马体和背外侧纹状体在环境几何表征中的作用。将大鼠放置在一个风筝形状的场地中，并让它们在每个直角角落探索两个不同的物体。然后在另一个房间里，将大鼠放入一个矩形场地，其中有探索阶段的两个物体之一的两个相同复制品，分别放在由一堵长墙隔开的两个相邻直角角落中。记录探索这两个物体所花费的时间，作为识别记忆的一种度量。由于两个物体相对于房间处于不同位置（探索阶段和测试阶段不同）且全局几何形状（探索阶段和测试阶段也不同），对物体的差异探索必定是相对于其局部几何背景对该物体最初习惯化的结果。结果表明，与假手术对照组相比，海马体和背外侧纹状体损伤的大鼠在处理环境的局部几何特征方面存在障碍，尽管一项对照实验表明这些大鼠在标准物体识别任务中没有受损。背外侧纹状体先前被认为与自我中心路线学习有关，但结果表明背外侧纹状体在处理环境空间布局方面具有意想不到的作用。这些结果首次证明，海马体和背外侧纹状体损伤会损害局部环境几何特征的自发编码。
