NEURAL BASIS FOR SPATIAL COGNITION

这一建议描述了一系列的实验，将检查意志 研究空间信息在哺乳动物大脑中是如何处理的。 在 以前的研究中， 后下托（位于海马结构内）， 动物头部方向的函数，独立于动物的 行为和空间位置。 这个空间信号提供了一个模型系统 来研究初级感觉信息是如何通过各种 感觉通路，被转化为“更高层次的认知信号” 代表有机体与其环境的空间关系。 的 在中枢神经系统中完成这种转化的机制 系统是未知。 该建议的第一个目的是研究 头部方向细胞信号在大脑中处理。 为了解决这个 在这一问题上，将采取三种实验方法。 首先，解剖学 后下托的连通性将使用神经网络来识别。 解剖追踪技术 二、电生理特性 和空间敏感性的单个神经元在大脑区域投射到 检查后下托。 最后是封头的加工 将在大鼠中监测细胞活性，其中病变或 化学处理中断了电路。 总的来说， 从这些研究中获得的结果将提高我们对 参与头部方向细胞激活的神经回路。 第二条调查线将集中在动物如何使用头部 行为和空间导航中的方向细胞信号。 迄今为止， 方向的细胞活动只记录在大鼠中， 圆柱形环境中获取食物颗粒。 拟议的研究将 评估不同行为范式如何影响头向细胞 活动 例如，将监测头部方向细胞活动 当动物进行经典条件反射或视觉辨别时， 任务 额外的实验将确定头部方向细胞是否 活性可以通过环境操作来改变。 在这些 在实验中，将作为动物观察头部方向细胞活性 在一个新的或以前熟悉的环境中学习它的方向。 最后，NMDA受体在建立动物空间记忆中的作用， 将探索在新环境中的定位。 从拟议的实验结果将提供洞察如何 空间信息是在大脑中处理的。 这些发现 对人类健康和行为的影响。 这是常见的老年人 老年痴呆症是一种经常与 后下托有明显的病理改变， 在需要持续监督的情况下出现定向障碍。 了解空间信息在老鼠大脑中是如何处理的， 人类空间过程复杂性的线索。

This proposal describes a series of experiments which will examine will examine how spatial information is processed in the mammalian brain. In previous studies a population of neurons was identified in the postsubiculum (located within the hippocampal formation) which discharge as a function of the animal's head direction, independent of the animal's behavior and spatial location. This spatial signal provides a model system for examining how primary sensory information, entering through various sensory pathways, is transformed into a 'higher level cognitive signal" representing the organism's spatial relationship with its environment. The mechanisms which accomplish this transformation in the central nervous system are not known. The first aim of the proposal is to examine how the head direction cell signal is processed in the brain. To address this issue, three experimental approaches will be pursed. First, the anatomical connectivity of the postsubiculum will be identified using neural anatomical tracing techniques. Second, the electrophysiological properties and spatial sensitivities of single neurons in brain regions projecting to the postsubiculum will be examined. Finally, the processing of head direction cell activity will be monitored in rats in which lesions or chemical treatments have interrupted the circuit. Taken together, the results obtained from these studies will improve our understanding of the neural circuitry involved in the activation of head direction cells. A second line of investigation will focus on how an animal uses the head direction cell signal in behavior and spatial navigation. To date, head direction cell activity has been recorded only in rats moving freely in a cylindrical environment retrieving food pellets. The proposed studies will evaluate how different behavioral paradigms effect head direction cell activity. For example, head direction cell activity will be monitored while an animal performs a classical conditioning or visual discrimination task. Additional experiments will determine whether head direction cell activity can be modified by environmental manipulations. In these experiments, head direction cell activity will be observed as an animal learns its orientation in a novel, or previously familiar environment. Finally, the role of NMDA receptors in establishing an animal's spatial orientation in a novel environment will be explored. The results from the proposed experiments will provide insight into how spatial information is processed in the brain. These findings have implications from human health and behavior. It is common for elderly patients and patients with Alzheimer's disease, a disease often associated with marked pathology of the postsubiculum, to experience spatial disorientation to the extent that constant supervision is required. Learning how spatial information is processed in the rat brain will give us clues about the complex nature of spatial processes in humans.