Overlap among Spatial Memories Triggers Repulsion of Hippocampal Representations.
Overlap among Spatial Memories Triggers Repulsion of Hippocampal Representations.
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空间记忆之间的重叠会触发海马表示的排斥。
DOI：
10.1016/j.cub.2017.06.057
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发表时间：
2017-08-07
期刊：
影响因子：
--
通讯作者：
Kuhl BA
中科院分区：
文献类型：
--
作者：
Chanales AJH;Oza A;Favila SE;Kuhl BA
在空间导航和情景记忆领域，海马体被认为在消除重叠事件的歧义（模式分离）表征中起着关键作用。然而，目前还不完全清楚海马模式是如何以及为什么分开的。在这里，我们测试了事件重叠在学习过程中发展的海马体表征中引发“排斥”的观点。利用自然路线学习范式和人类功能磁共振成像数据的时空模式分析，我们发现海马对重叠路线的表征随着学习逐渐分化，以至于它们变得不像非重叠事件的表征那么相似。换句话说，海马体不仅消除了重叠事件的歧义，而且形成了“逆转”路线之间客观相似性的表征。这一发现对海马体是选择性的，并不是模式分离的标准理论所预测的。至关重要的是，由于我们使用的重叠路径刺激最终会分化（因此每个路径包含重叠和非重叠的片段），我们能够测试反转效应是否对重叠片段具有选择性。事实上，一旦重叠的路线分化（消除空间和视觉相似性），海马体表征反而变得相对更相似。最后，使用一种新颖的分析方法，我们表明单个海马体素最初在路径表征中共享的程度可以预测学习相关分离的程度。总的来说，这些发现表明，事件重叠触发了海马体表征的排斥——这一发现为海马体表征如何以及为什么分离提供了关键的机制见解。Chanales等人报告说，人类海马体中重叠空间路径的表征随着学习而显著分化，最终变得不如非重叠路径的表征相似。这些发现表明，事件重叠触发了海马表征的排斥。
Across the domains of spatial navigation and episodic memory, the hippocampus is thought to play a critical role in disambiguating (pattern separating) representations of overlapping events. However, it is not fully understood how and why hippocampal patterns become separated. Here, we test the idea that event overlap triggers a ‘repulsion’ among hippocampal representations that develops over the course of learning. Using a naturalistic route-learning paradigm and spatiotemporal pattern analysis of human fMRI data, we found that hippocampal representations of overlapping routes gradually diverged with learning to the point that they became less similar than representations of non-overlapping events. In other words, the hippocampus not only disambiguated overlapping events, but formed representations that ‘reversed’ the objective similarity among routes. This finding, which was selective to the hippocampus, is not predicted by standard theoretical accounts of pattern separation. Critically, because the overlapping route stimuli that we used ultimately diverged (so that each route contained overlapping and non-overlapping segments), we were able to test whether the reversal effect was selective to the overlapping segments. Indeed, once overlapping routes diverged (eliminating spatial and visual similarity), hippocampal representations paradoxically became relatively more similar. Finally, using a novel analysis approach, we show that the degree to which individual hippocampal voxels were initially shared across route representations was predictive of the magnitude of learning-related separation. Collectively, these findings indicate that event overlap triggers a repulsion of hippocampal representations—a finding that provides critical mechanistic insight into how and why hippocampal representations become separated. Chanales et al. report that representations of overlapping spatial routes in the human hippocampus dramatically diverge with learning, ultimately becoming less similar than representations of non-overlapping routes. These findings suggest that event overlap triggers repulsion of hippocampal representations.
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DOI：
10.1523/jneurosci.6021-09.2010
发表时间：
2010-05-26
期刊：
The Journal of neuroscience : the official journal of the Society for Neuroscience
影响因子：
--
作者：
Brown TI;Ross RS;Keller JB;Hasselmo ME;Stern CE
通讯作者：
Stern CE
影响因子：
19.9
作者：
Epstein, Russell A.
通讯作者：
Epstein, Russell A.
影响因子：
5.3
作者：
LaRocque, Karen F.;Smith, Mary E.;Wagner, Anthony D.
通讯作者：
Wagner, Anthony D.
影响因子：
56.9
作者：
Brown, Thackery I.;Carr, Valerie A.;Wagner, Anthony D.
通讯作者：
Wagner, Anthony D.
DOI：
10.1073/pnas.1319641111
发表时间：
2014-07-22
影响因子：
11.1
作者：
Chadwick, Martin J.;Bonnici, Heidi M.;Maguire, Eleanor A.
通讯作者：
Maguire, Eleanor A.