FMRI investigation of sequence learning in humans

本项目将研究海马区和相关的内侧颞叶(MTL)结构在脑内的作用。 顺序记忆。这些研究是以我们最近的发现为指导的，具有神奇的功能共振 成像(FMRI)表明人类海马体在序列学习的早期阶段被激活 (Schendan Et A)，2003)，以及我们最近的动物和建模研究表明，海马体是 在记忆中对时间顺序和重叠歧义的消除至关重要(Fortin等人，2002) 记忆中的事件顺序(Sohal和Hasselmo，1998；Agster等人，2002)。拟议中的项目具有 三个具体目标。第一个目的是使用功能磁共振成像来探索海马区受累的范围 人类的序列学习。实验1和实验2将检查海马体、副海马体、前额叶、 与纹状体活动编码过程中的编码、延迟和提取部分的编码任务将形成对比 对项目、项目序列和空间上下文信息的学习和记忆性能。这些 事件相关功能磁共振研究直接平行研究已经和将在动物模型中进行的研究。 我们的假设是，海马体不仅对联想和语境学习至关重要，而且对 在独特的经历中记住事件的顺序。我们进一步预测，地球周围的活动将 与项目学习有关，但与上下文或顺序学习无关。第二个目标是使用功能磁共振成像来探索 海马体在序列歧义消除中的作用。动物模型中的实验直接平行研究 (阿格斯特等人，2002年；伍德等人，2000年)。实验3将检测在编码重叠时的海马区激活 而非重叠的非空间序列。实验4是Exp的空间模拟。3，并将审查 使用重叠和非重叠路径在虚拟现实迷宫中导航。第三个目标是 在序列学习中，使用功能磁共振成像对比内侧颞叶、前额叶和纹状体系统。实验5. 考察了“前额”N-back任务中嵌入序列的内隐序列学习。实验6. 检查附带图片中一阶(FOG)或二阶条件(SOC)序列的学习 编码任务。据预测，雾序列将激活纹状体，但不会激活MTL，而 SoC序列将激活MTL。合并的研究将提供一种假设驱动的检验 情节序列学习与所提出的研究和模型非常相似。

This project will investigate the role of the hippocampus and related medial temporal lobe (MTL) structures in sequence memory. These studies are guided by our recent findings with functional magetic resonance imaging (fMRI) indicating that the human hippocampus is activated in early stages of sequence learning (Schendan et a)., 2003), and also our recent animal and modeling studies that suggest the hippocampus is critical in memory for temporal order (Fortin et al., 2002), and for the disambiguation of overlapping sequences of events in memory (Sohal and Hasselmo, 1998; Agster et al., 2002). The proposed project has three specific aims. The first aim is to use fMRI to explore the scope of hippocampal involvement in sequence learning in humans. Experiments 1 and 2 will examine hippocampal, parahippocampal, prefrontal, and striatal activity during the encoding, delay, and retrieval components of encoding tasks that will contrast learning and memory performance for items, sequences of items, and spatial context information. These event-related fMRI studies directly parallel studies that have been and will be carried out in animal models. Our hypothesis is that the hippocampus is critical not only for associative and contextual learning, but also for remembering the order of events in unique experiences. We further predict that perirhinal activity will relate to item learning, but not contextual or sequence learning. The second aim is to use fMRI to explore the role of the hippocampus in sequence disambiguation. Experiments directly parallel studies in animal models (Agster et al., 2002; Wood, et al, 2000). Exp. 3 will examine hippocampal activation in encoding overlapping versus non-overlapping non-spatial sequences. Exp. 4 is the spatial analog of Exp. 3, and will examine navigation through virtual reality mazes using overlapping and non-overlapping paths. The third aim is to use fMRI to contrast the medial temporal lobe, prefrontal, and striatal systems in sequence learning. Exp. 5 examines implicit sequence learning in a sequence embedded in a "prefrontal" N-back task. Exp. 6 examines learning of first order (FOG) or second order conditional (SOC) sequences in an incidental picture encoding task. The prediction is that FOG sequences will activate the striatum but not the MTL, whereas SOC sequences will activate the MTL. The combined studies will provide a hypothesis-driven examination of episodic sequence learning that closely parallels the studies and models proposed.