Essential role of the hippocampal formation in rapid learning of higher-order sequential associations
Essential role of the hippocampal formation in rapid learning of higher-order sequential associations
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DOI：
10.1523/jneurosci.0441-06.2006
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发表时间：
2006-04-12
影响因子：
5.3
通讯作者：
Eichenbaum, H
中科院分区：
文献类型：
--
作者：
Ergorul, C;Eichenbaum, H
人类健忘症和功能成像研究的证据表明，内侧颞叶参与了串行反应时间（SRT）任务获取过程中高阶序列的学习。然而，这些研究尚未阐明海马结构是否对此类学习特别重要。在这里，我们开发了 SRT 任务的啮齿动物模型，以检查海马结构在学习一阶和二阶条件序列中的具体作用。选择性海马结构损伤会加速性能并损害一级和二级序列的准确性。此外，对照组仅根据序列的复杂性来区分序列，而海马病变的动物最初仅根据序列的长度来区分序列。在多次训练中，海马大鼠逐渐根据序列的复杂性而不是长度来区分序列，与对照组相似。这些发现表明海马结构本身在快速获取高阶序列表征中起着至关重要的作用。海马外系统也可以获得复杂的顺序表征，尽管是通过渐进的学习机制。
Evidence from studies of amnesia and functional imaging in humans suggest that the medial temporal lobe is involved in the learning of higher-order sequences during acquisition of serial reaction time (SRT) tasks. However, these studies have not clarified whether the hippocampal formation specifically is essential to this type of learning. Here, we developed a rodent model of the SRT task to examine the specific roles of the hippocampal formation in learning first-and second-order conditional sequences. Selective hippocampal formation lesions speeded performance and impaired accuracy on both first-and second-order sequences. Additionally, whereas controls distinguished the sequences based on their complexity alone, animals with hippocampal lesions initially differentiated sequences only by their length. Over multiple sessions, hippocampal rats gradually differentiated sequences by their complexity and not length, similar to control subjects. These findings indicate that the hippocampal formation itself plays an essential role in rapid acquisition of higher-order sequence representations. Extrahippocampal systems can also acquire complex sequential representations, albeit via a gradual learning mechanism.