The neural basis of spatial context.

描述（由申请人提供）：我们对日常事件的有意识记忆（即情景记忆）是由我们多年来经历的许多人，地点和事物之间的无数联系组成的。这种记忆由海马记忆系统支持，也称为内侧颞叶记忆系统。组成海马记忆系统的结构，包括海马结构和海马旁区域，在灵长类和啮齿类之间显示出显著的连接和功能同源性。因此，啮齿类动物为研究人类记忆提供了一个很好的动物模型。目前，关于海马和海马旁区的个体结构如何参与情景记忆存在很大的分歧。拟议的研究将采用大鼠模型来检查两个海马旁区域对记忆的贡献，即嗅后皮质（POR;灵长类海马旁皮质的啮齿动物同源物）和嗅周皮质（PER）。POR被认为参与处理空间/上下文信息，PER在处理对象信息中具有确定的作用。然而，这两个区域之间的相互作用还没有得到很好的理解。我的指导性假设是，POR和PER之间的直接联系提供了将单个项目与位置联系起来的联想表征的神经回路。具体的目标将采用一种新的行为装置来测试这一假设的三个关键方面：1）POR和PER都是将物体与位置联系起来的关联表征所必需的，2）在海马体的上游形成了物体-上下文关联，以及3）在PER和POR中都将观察到物体-上下文关联的神经相关性。实验1和2将采用病变和失活分析，以确定是否PER和POR是必要的处理二维视觉“对象”和图案地板背景，分别，以及是否关联，链接项目和上下文的海马上游形成。在实验3中，将记录单个单元活动和局部场电位，以检查POR和PER中的神经活动与需要处理项目和上下文的任务上的性能的相关性。如果完成，这些实验将提供更深入的了解空间背景在情景记忆中的作用，包括背景在哪里表示，以及这些表示如何影响记忆的其他方面，例如识别和检索。更好地理解这些问题不仅会告知我们对记忆的基本理解，而且有可能改善与脑创伤或疾病相关的记忆障碍的治疗，例如阿尔茨海默病，癫痫和精神分裂症。

DESCRIPTION (provided by applicant):Our conscious memories of daily events (i.e. episodic memory) are made of up countless associations among the many people, places, and things we have experienced over the years. This sort of memory is supported by the hippocampal memory system, also called the medial temporal lobe memory system. The structures that compose the hippocampal memory system, including the hippocampal formation and parahippocampal regions, display remarkable connectional and functional homology between primates and rodents. Thus, rodents provide an excellent animal model for studying human memory. Currently, there is substantial disagreement about how individual structures within the hippocampal and parahippocampal regions are involved in episodic memory. The proposed studies will employ a rat model to examine the contributions of two parahippocampal regions to memory, the postrhinal cortex (POR;rodent homolog to primate parahippocampal cortex) and the perirhinal cortex (PER). POR is thought to be involved in processing spatial/contextual information and PER has an identified role in processing object information. The interactions between the two regions, however, are not well understood. My guiding hypothesis is that the direct connections between the POR and PER provide the neural circuitry for associative representations that link individual items to locations. The specific aims will employ a novel behavioral apparatus to test three key aspects of this hypothesis:1) both the POR and the PER are necessary for associative representations that link objects to places, 2) object-context associations are formed upstream of the hippocampus, and 3) neural correlates of object-context associations will be observed in both PER and POR. Experiments 1 and 2 will employ lesion and inactivation analysis to determine if the PER and POR are necessary for processing 2D visual "objects" and patterned floor backgrounds, respectively, and whether associations that link items and context are formed upstream of the hippocampus. In Experiment 3, single unit activity and local field potentials will be recorded to examine correlates of neural activity in the POR and PER with performance on a task that requires processing of items and contexts. If completed, these experiments will provide greater insight into the role of spatial context in episodic memory, including where context is represented, and how such representations influence other aspects of memory, for example recognition and retrieval. A better understanding of these issues will not only inform our basic understanding of memory, but has the potential to improve treatment of memory impairments associated with brain trauma or disease,e.g. Alzheimer's Disease, epilepsy, and schizophrenia.