FMRI investigation of sequence learning in humans

本项目将研究海马和相关的内侧颞叶（MTL）结构在 顺序存储器这些研究是由我们最近的研究结果与功能磁共振 功能磁共振成像（fMRI）显示，人类海马在序列学习的早期阶段被激活 （Schendan等人），2003年），以及我们最近的动物和模型研究，表明海马是 对于时间顺序的记忆至关重要（Fortin等人，2002年），并为消除重叠 记忆中的事件序列（Sohal和Hasselmo，1998; Agster等，2002年）。拟议项目已 三个具体目标。第一个目的是使用fMRI来探索海马受累的范围， 人类的序列学习实验1和2将检查海马，海马旁，前额， 在编码任务的编码、延迟和提取过程中纹状体的活动， 项目、项目序列和空间背景信息的学习和记忆表现。这些 事件相关的功能磁共振成像研究直接平行的研究，已经和将要进行的动物模型。 我们的假设是，海马体不仅对于联想和情境学习至关重要，而且对于 记忆独特经历中事件的顺序。我们进一步预测， 与项目学习有关，但与上下文或序列学习无关。第二个目的是使用功能磁共振成像来探索 海马体在序列消歧中的作用。动物模型中的实验直接平行研究 （Agster等人，2002; Wood等人，2000）。Exp. 3将检查海马激活编码重叠 与非重叠非空间序列相比。Exp. 4是Exp的空间模拟。3、会检查 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 使用功能磁共振成像对比内侧颞叶，前额叶和纹状体系统在序列学习。Exp. 5 研究内隐序列学习的序列嵌入在一个“前额叶”N-back任务。Exp. 6 检查学习的一阶（FOG）或二阶条件（SOC）序列在附带图片 编码任务。预测是FOG序列将激活纹状体，但不会激活MTL，而 SOC序列将激活MTL。合并研究将提供一个假设驱动的检查， 情节序列学习，密切平行的研究和提出的模型。

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.