Hippocampal control of repetition effects for associative stimuli
Hippocampal control of repetition effects for associative stimuli
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DOI：
10.1002/hipo.22278
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发表时间：
2014-07-01
期刊：
影响因子：
3.5
通讯作者：
Axmacher, Nikolai
中科院分区：
文献类型：
--
作者：
Kremers, Nico A. W.;Deuker, Lorena;Axmacher, Nikolai
最近的研究结果表明，重复效应与推测由海马体支持的情景记忆过程相互作用。因此，情景记忆的形成或完善可能与从海马体到新皮质的调节信号有关，这会导致更稀疏或更扩展的刺激表征（重复抑制或增强），具体取决于刺激的类型和大脑部位。该框架表明，刺激最初呈现期间的海马活动与重复效应的强度相关。在这里，我们在一项功能磁共振成像研究中测试了这一假设，其中面孔和建筑物之间的关联被呈现了两次。 BOLD 响应显示梭形面部区域 (FFA) 和海马旁区域 (PPA) 的重复抑制，很可能是由于现有类别表示的细化。第一次呈现期间的海马活动与重复抑制量相关，特别是在 FFA 中。在后顶叶皮层的 BOLD 反应中观察到重复增强效应，可能与联想刺激新表征的形成有关。顶叶 BOLD 重复效应的大小取决于成功的记忆形成。这些发现表明，重复增强和重复抑制效果都受到海马体调节信号的影响。 (c) 2014 年 Wiley 期刊公司。
Recent findings suggest that repetition effects interact with episodic memory processes that are putatively supported by the hippocampus. Thus, the formation or refinement of episodic memories may be related to a modulating signal from the hippocampus to the neocortex which leads to sparser or more extended stimulus representations (repetition suppression or enhancement), depending on the type of stimulus and the brain site. This framework suggests that hippocampal activity during the initial presentation of a stimulus correlates with the magnitude of repetition effects. Here, we tested this hypothesis in an fMRI study in which associations between faces and buildings were presented twice. BOLD responses showed repetition suppression in fusiform face area (FFA) and parahippocampal place area (PPA), most likely due to a refinement of existing category representations. Hippocampal activity during the first presentations was correlated with the amount of repetition suppression, in particular in the FFA. Repetition enhancement effects were observed on BOLD responses in posterior parietal cortex, possibly related to the formation of new representations of associative stimuli. The magnitude of parietal BOLD repetition effects depended on successful memory formation. These findings suggest that both repetition enhancement and repetition suppression effects are influenced by a modulating signal from the hippocampus. (c) 2014 Wiley Periodicals, Inc.