HEBB MARR NETWORKS THE HIPPOCAMPUS AND SPATIAL MEMORY

描述(改编自申请者摘要)：本项目的目标是 要了解这些机制和计算原理 对依赖于功能海马体(HC)的记忆进行编码，以及它们的 随后整合到独立于HC的长期存储中，假设 在新皮质(NC)。这是改善记忆力的先决条件 由发育异常、疾病、创伤、衰老引起的疾病 或者滥用药物。工作假说是，长期的 记忆是从过去的经验中构建内部表征， 反映了环境的统计规律，因此 允许适当的概括和适当的回应。这样的学习 需要对要存储的项目进行反复交错暴露， 在每次试验中对突触进行微小的调整。尝试存储新的 这种记忆中的所有信息一下子就会导致“灾难性的干扰” 物品已经存储；然而，生存通常需要添加新的物品 到现有的范畴结构，只有一次或几次经验。 假设HC生成并存储紧凑的表示 这类事件的空间上下文与 当时在各自NC区域内的事件的各个组成部分 体验的一部分。通过自发地重新激活这些存储的上下文， HC有助于以连贯的方式恢复原始模式 时尚贯穿整个NC，并因此提供所需的“培训试验” 而系统处于“离线”状态。这提供了一个框架来理解 HC损伤后出现的时间渐进性逆行性遗忘现象， 以及为什么以及如何进行记忆整合。同时使用 来自50-150个神经元的记录表明，群体编码 新的环境在探索过程中迅速发展，而 在集体活动中可以观察到最近发生的事件和事件序列 在安静清醒和慢波睡眠期间，HC和NC中神经元的数量。 拟议的录音研究涉及该理论的具体方面： 记忆轨迹离线再激活的稳健性是否 与后续性能相关；是否会有更多的远程内存 在脱机期间与较新的文件交错；是否有 记忆重新激活的逆行梯度；哪种行为状态最多 有利于重新激活；NC在多大程度上也会发生重新激活 在脱机期间；NC和HC重新激活是否反映 最近同样的经历；以及功能正常的HC是否需要 在NC中重新激活最近的记忆。最后，建议测试 通过在HC中施加电活动的分布模式的理论 在空间信息获取过程中的空间结构电刺激 信息和离线期间。

DESCRIPTION (Adapted from applicant's abstract): The aim of this project is to understand the mechanisms and computational principles underlying the encoding of memories that depend on a functional hippocampus (HC), and their subsequent consolidation into HC-independent, long-term storage, presumably in the neocortex (NC). This is a prerequisite to ameliorating memory disorders resulting from developmental abnormalities, disease, trauma, aging or drug abuse. The working hypothesis is that the function of long-term memory is to construct, from past experience, internal representations that reflect the statistical regularities of the environment, and which thus permit adaptive generalization and appropriate responses. Such learning requires repeated, interleaved exposure to the items to be stored, with small adjustments to the synapses on each trial. Attempts to store new information all at once in such a memory lead to "catastrophic interference" with items already stored; however, survival often requires adding new items to the existing categorical structure, with only one or a few experiences. It is hypothesized that HC generates and stores compact representations of the spatial contexts of such events, which become associated with the individual components of the events in their respective NC areas at the time of the experience. By spontaneously reactivating these stored contexts, the HC facilitates the reinstatement of the original patterns in a coherent fashion throughout NC, and thus provides the required "training trials" while the system is "off-line". This provides a framework for understanding the phenomenon of temporally graded retrograde amnesia following HC damage, and why and how memory consolidation takes place. Using simultaneous recordings from 50-150 neurons, it has been shown that population-codes for novel environments develop rapidly during exploration, and that traces of recent events and event-sequences can be observed in the collective activity of neurons in both HC and NC during quiet wakefulness and slow-wave sleep. The proposed recording studies address specific aspects of the theory: whether the robustness of off-line reactivation of memory traces is correlated with subsequent performance; whether more remote memories are interleaved with newer ones during off-line periods; whether there is a retrograde gradient of memory reactivation; which behavioral states are most conducive to reactivation; to what extent reactivation also occurs in NC during the off-line periods; whether NC and HC reactivations reflect the same recent experiences; and whether a functional HC is necessary for reactivation of recent memory in NC. Finally, it is proposed to test the theory by imposing distributed patterns of electrical activity in HC using spatially structured electrical stimuli both during acquisition of spatial information and during off-line periods.