EVENT ENCODING IN NAVIGATION AND SPATIAL MEMORY

描述(申请人提供)：导航能力下降通常与老年有关，特别是与阿尔茨海默病(AD)有关。导航困难可能会对个人的自力更生造成毁灭性的影响，这种问题甚至可能是危险的，特别是在开车时。研究表明，这种与年龄相关的困难是专门出现的 通过在环境中旅行来创建结构化的认知地图的能力不足。这些心理地图是如何在导航过程中构建的，这一理论迫切需要用来设计对老年人迷路困难的反应。在这里，我们测试了一项新的提议，该提议限制了精神地图是如何从导航经验中建立起来的，以及精神地图的构建如何随着年龄的变化而变化。研究表明，一般而言，空间表征和空间记忆被组织成块；某些位置在记忆中被组合在一起。一些因素，如时间和空间的接近程度以及环境的显著物理特征，已被确定为决定哪些地点集中在一起的重要因素。然而，在确定特定的认知和神经机制来组织空间记忆方面所做的工作很少。我们认为，将经验时间分割成情节或事件是决定空间结构的一个重要因素 记忆。因此，改进时间编码可以提高空间记忆能力。在这些实验中，参与者将观看演员在特定环境(如建筑物)中导航的第一人称短片。在某些情况下，参与者会将电影分割成空间区域或事件，而在另一些情况下，功能磁共振成像(FMRI)将被用来监测电影观看过程中的大脑活动。在观看电影后，将测量导航环境的空间记忆，以检验以下假设：1)导航过程中的空间和时间分割影响后来对导航空间的记忆。2)与年龄相关的空间和时间分割机制的衰退与较差的空间记忆有关。3)老年人空间敏感脑区的时相活动紊乱，这种紊乱与空间记忆受损有关。这项研究的成功完成将为致力于解决与年龄相关的导航困难这一重要问题的研究人员和临床医生开辟一套新的认知和神经机制。从理论上讲，空间记忆中的结构测量对于诊断与早期痴呆症相关的导航困难可能特别有价值。如果与年龄相关的导航困难是通过时间分割障碍来调节的，这将为干预提供一个新的靶点。

DESCRIPTION (provided by applicant): Reduced navigation ability has been associated with advanced age in general and particularly with Alzheimer's disease (AD). Navigation difficulties can be devastating to an individual's self-reliance, and such problems can even be dangerous, particularly while driving. Research suggests that such age related difficulties arise specifically from deficits in the ability to create structured cognitive maps of environments from traveling around in them. Theories of how these mental maps are constructed during navigation are sorely needed to design responses to older adults' difficulties with getting lost. Here we test a novel proposal constraining how mental maps are built up from navigation experience and how mental map construction changes with age. Research suggests that spatial representations and spatial memory in general, are organized into chunks; certain locations are grouped together in memory. Several factors, such as temporal and spatial proximity and salient physical features of the environment have been identified as important in determining what locations get chunked together. However, little work has been done to identify specific cognitive and neural mechanisms by which spatial memory is organized. We propose that temporal segmentation of experience into episodes, or events, is an important factor in determining the structure of spatial memory. Therefore, improving temporal encoding could improve spatial memory. In these experiments, participants will view short first person movies of actors navigating through particular environments (e.g., buildings). In some cases, participants will segment the movies into spatial regions or events, and in others functional magnetic imaging (fMRI) will be used to monitor brain activity during movie viewing. After movie viewing, spatial memory for the navigated environments will be measured to test the following hypotheses: 1) Spatial and temporal segmentation during navigation affects later memory for the navigated space. 2) Age related declines in spatial and temporal segmentation mechanisms are associated with poorer spatial memory. 3) Phasic activity in spatially sensitive brain regions is disrupted in older adult, and this disruption is associated with spatial memory impairment. Successful completion of this research will open up a new set of cognitive and neural mechanisms as targets for researchers and clinicians working to address the important problem of age related navigation difficulty. Theoretically motivated measures of structure in spatial memory may prove particularly valuable for diagnosing navigation difficulties associated with early-stage dementia. If age-related navigating difficulties are mediated by temporal segmentation impairments, this will provide a novel target for intervention.