The hippocampus, memory, and spatial cognition

在过去的半个世纪里，神经科学取得了巨大的进步，因为新的工具和技术的进步使得提出关于神经元、突触、蛋白质和基因的结构和功能的越来越具体的问题成为可能。在了解电路、网络和大脑系统的组织和功能方面进展缓慢。在这种情况下，有时人们会忽视对认知本身的描述有多么重要？感知、注意力、记忆、语言和行动的组织。人们想要了解它的组成部分，并了解认知的组成部分如何与大脑底物相关。这里提出的工作解决了一个关于大脑如何组织其记忆功能的基本问题。问题是，短期记忆和长期记忆是否真的是不同的实体，以至于短期记忆独立于海马体(和相关结构)；或者这一原理是否存在空间认知的例外。这是一个深刻而根本的问题。海马体及相关结构是否具有在线计算功能？或者这些结构实际上只在短期存储容量已被超过时才需要。为了评估这两个观点，提出了五项研究，针对患有海马区病变(或包括相关结构的较大病变)的个体，使用开放空间导航、虚拟现实以及空间想象测试。对于有选择性海马区、内嗅区或顶叶皮质损害的大鼠，建议进行平行的路径整合研究。了解记忆和空间认知之间的关系是理解大脑如何组织其记忆功能的基础。

Neuroscience has made enormous progress during the past half century as new tools and technological advances have made it possible to ask increasingly specific questions about the structure and function of neurons, synapses, proteins, and genes. Progress has been slower in understanding the organization and function of circuits, networks, and brain systems. And in that context, it is sometimes overlooked how important it is to have an account of cognition itself ? perception, attention, memory, language, and the organization of action. One wants to understand its components and to understand how the components of cognition can be related to brain substrates. The work proposed herein addresses a fundamental issue about how the brain has organized its memory functions. The issue is whether short-term and long-term memory are indeed distinct entities, such that short-term memory is independent of the hippocampus (and related structures); or whether an exception to that principle exists in the case of spatial cognition. It is a deep and fundamental matter. Do the hippocampus and related structures have online, computational functions? Or are these structures in fact needed only when short-term memory capacity has been exceeded. To evaluate these two perspectives, five studies are proposed in individuals with hippocampal lesions (or larger lesions that include related structures) using navigation in open space, virtual reality, as well as a test of spatial imagining. Parallel work on path integration is proposed for rats with selective lesions of the hippocampal, entorhinal, or parietal cortex. Understanding the relationship between memory and spatial cognition is fundamental to understanding how the brain has organized its memory functions.