Persistent posterior and transient anterior medial temporal lobe activity during navigation
Persistent posterior and transient anterior medial temporal lobe activity during navigation
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DOI：
10.1016/j.neuroimage.2010.05.074
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发表时间：
2010-10
期刊：
影响因子：
5.7
通讯作者：
Jian Xu;Hallvard Røe Evensmoen;H. Lehn;Carl W. S. Pintzka;A. Håberg
中科院分区：
文献类型：
--
作者：
Jian Xu;Hallvard Røe Evensmoen;H. Lehn;Carl W. S. Pintzka;A. Håberg
一个功能隔离沿着轴的内侧颞叶（MTL）已被建议。简而言之，人们认为后部海马体代表环境细节和/或编码空间，而前部海马体更多地代表整体环境和/或支持行为。因此，导航的不同阶段应在MTL内招募不同的结构。基于动物研究和人类神经成像数据，导航的初始阶段，即，自定位、目标定位和路径规划应该依赖于独立于即将到来的导航需求的前MTL，而后MTL应该在整个导航过程中是活动的。我们使用功能磁共振成像与导航在一个学习的大型虚拟办公室景观与许多复杂的地标在不同的导航条件下测试这一预测。最初的导航阶段专门涉及前MTL。增加活动被发现双边在喙和尾内嗅皮层。据我们所知，这是第一次报告的内嗅活动在虚拟导航中检测到的直接比较。此外，在初始阶段，双侧前海马和前海马旁皮质显着更活跃。活动持续整个航行期间被发现在右后海马和海马旁皮质。只有当虚拟环境保持不变时，才能检测到整个导航期间的海马活动。导航成功与活动在前右侧海马的初始阶段，并在整个导航期间更后方的海马。BOLD信号时间过程的曲线图表明，在前海马的活动是短暂的，而在后海马的活动在整个航行期间定期达到峰值。这些结果支持MTL内导航阶段的功能分离。前MTL似乎完成与环境相关的关联，并提供导航的行为计划，而后部分则跟踪当前位置。
A functional segregation along the posterior–anterior axis of the medial temporal lobe (MTL) has been suggested. In brief, it is thought that the posterior hippocampus represents environmental detail and/or encodes space, whereas the anterior part represents the environment more as a whole and/or subserves behavior. Different phases of navigation should thus recruit different structures within the MTL. Based on animal studies and neuroimaging data from humans, the initial phase of navigation, i.e., self-localization, target localization and path planning, should depend on the anterior MTL independent of upcoming navigational demands, whereas posterior MTL should be active throughout navigation. We tested this prediction using fMRI with navigation in a learned large-scale virtual office landscape with numerous complex landmarks under different navigational conditions. The initial navigational phase specifically engaged the anterior MTL. Increased activity was found bilaterally in the rostral and caudal entorhinal cortex. This is, to our knowledge, the first report of entorhinal activity in virtual navigation detected in a direct comparison. Also bilateral anterior hippocampus and anterior parahippocampal cortex were significantly more active during the initial phase. Activity lasting throughout the navigational period was found in the right posterior hippocampus and parahippocampal cortex. Hippocampal activity for the entire navigation period was only detected when the virtual environment remained unaltered. Navigational success was positively correlated with activity in the anterior right hippocampus for the initial phase, and more posteriorly in the hippocampus for the whole navigation period. Plots of the BOLD signal time course demonstrated that activity in the anterior hippocampus was transient whereas activity in the posterior hippocampus peaked regularly throughout the entire navigation period. These results support a functional segregation within the MTL with regard to navigational phases. The anterior MTL appears to complete associations related to the environment at large and provide a behavioral plan for navigation, whereas the posterior part keeps track of current location.