SPATIAL FUNCTIONS OF THE MEDIAL TEMPORAL LOBE

内侧颞叶结构如何影响记忆？找到这个问题的答案是神经科学研究的长期目标。 最近的研究结果，从神经解剖，行为和功能成像研究提供了新的见解，这些内侧颞叶结构，嗅周和海马旁皮质的潜在功能。 这些发现表明，像海马结构，这些皮质内侧颞叶区也可能有助于重要的空间功能。 为了解决这种可能性，拟议的研究结合使用敏感的神经解剖追踪技术和单单位神经生理学技术，探索嗅周和海马旁皮质在空间功能的两个方面的作用：空间表征和空间记忆。 顺行追踪技术将被用来定义区域和层状地形海马旁的输入所产生的“背流”结构参与处理刺激的位置。单单位生理学技术将被用来定义在动物执行延迟匹配放置任务时，由嗅周和海马旁皮质中的神经元携带的空间和记忆信息的种类。 这些实验也将定义这些区域中位置选择神经元的空间参照系。 一个单独的任务将被用来检查在形成新的长期记忆的空间信息的嗅周和海马旁神经元的作用。 当猴子在一组复杂的视觉“场景”中学习特定奖励目标的空间位置时，神经活动将被记录下来。 分析将针对识别与学习这些新的、长期的位置-场景关联相关的神经活动的任何“调谐”。 由于空间信息的记忆在人类情景记忆（即事件记忆）中起着如此重要的作用，这些研究的结果也可能有助于建立猴子实验工作与人类大脑记忆基础研究之间的联系。

How do medial temporal lobe structures contribute to memory? Finding the answer to this question is a long-term goal of neuroscience research. Recent findings from neuroanatomical, behavioral and functional imaging studies have provided new insight into the potential functions of two of these medial temporal lobe structures, the perirhinal and parahippocampal cortices. These findings suggest that like the hippocampal formation, these cortical medial temporal lobe areas may also contribute importantly to spatial functions. To address this possibility, proposed research combines the use of sensitive neuroanatomical tracing techniques and single-unit neurophysiological techniques to explore the role of the perirhinal and parahippocampal cortices in two aspects of spatial function: spatial representation and spatial memory. Anterograde tracing techniques will be used to define the regional and laminar topography of parahippocampal inputs arising from "dorsal stream" structures involved in processing stimulus location. Single unit physiological techniques will be used to define the kinds of spatial and mnemonic information carried by neurons in the perirhinal and parahippocampal cortices as animals perform a delayed match to place task. These experiments will also define the spatial frame of reference of the place-selective neurons in these areas. A separate task will be used to examine the role of perirhinal and parahippocampal neurons in the formation of new long-term memories for spatial information. Neural activity will be recorded as monkeys learn the spatial locations of particular rewarded targets in the context of a set of complex visual "scenes". Analyses will be directed at identifying any "tuning" of neural activity associated with learning these new, long-term location-scene associations. Because memory for spatial information plays such a prominent role in human episodic (i.e. event) memory, findings from these studies may also serve to establish links between experimental work in monkeys and current work on the brain basis of memory in humans.