Prefrontal-hippocampal dynamics involved in learning regularities across episodes
Prefrontal-hippocampal dynamics involved in learning regularities across episodes
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DOI：
10.1093/cercor/bhh211
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发表时间：
2005-08-01
期刊：
影响因子：
3.7
通讯作者：
Reith, W
中科院分区：
文献类型：
--
作者：
Doeller, CF;Opitz, B;Reith, W
利用功能磁共振成像技术，研究了情景特异性记忆和情景间规律性不变记忆的神经关联。志愿者们必须学习物体和位置之间的连词。在不变学习条件下，位置保持不变，使受试者能够在不同的试验中学习规律。相比之下，在上下文特定条件下，客体位置连词是唯一的。在不变学习条件下，表现的提高与学习相关的额下回和腹侧纹状体激活的增加和海马激活的减少是平行的。相反，在情境特定条件下，海马体的激活在试验中是恒定的。我们认为，学习相关的海马激活模式可能是由于一旦提取规则，关系绑定需求减少。此外，我们提出与学习相关的前额叶调制反映了在不同试验中提取和保持规律的要求，以及在提取的知识基础上对物体位置连词的调整。最后，我们的数据表明，腹侧纹状体编码空间特征的可预测性作为学习的功能。综上所述，这些结果表明了不同大脑区域在学习规则过程中相对角色的转变：规则学习的特征是从海马到前额叶-纹状体大脑系统的转变。
Using functional magnetic resonance imaging, the neural correlates of context-specific memories and invariant memories about regularities across episodes were investigated. Volunteers had to learn conjunctions between objects and positions. In an invariant learning condition, positions were held constant, enabling subjects to learn regularities across trials. By contrast, in a context-specific condition object-position conjunctions were trial unique. Performance increase in the invariant learning condition was paralleled by a learning-related increase of inferior frontal gyrus activation and ventral striatal activation and a decrease of hippocampus activation. Conversely, in the context-specific condition hippocampal activation was constant across trials. We argue that the learning-related hippocampal activation pattern might be due to reduced relational binding requirements once regularities are extracted. Furthermore, we propose that the learning-related prefrontal modulation reflects the requirement to extract and maintain regularities across trials and the adjustment of object-position conjunctions on the basis of the extracted knowledge. Finally, our data suggest that the ventral striatum encodes the increased predictability of spatial features as a function of learning. Taken together, these results indicate a transition of the relative roles of distinct brain regions during learning regularities across multiple episodes: regularity learning is characterized by a shift from a hippocampal to a prefrontal-striatal brain system.