PATTERN COMPLETION AND PREDICTION ERROR IN HIPPOCAMPUS: A HI-RES FMRI STUDY

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心机构，不一定为研究者机构。海马体被认为是陈述性记忆的关键，尽管人类海马体的子领域的功能贡献仍然不明确。海马体的解剖结构包括齿状回、CA 3、CA 1和下托，这表明CA 3和CA 1可能不同地有助于基于记忆的预测和预测错误的检测（Lisman & Grace，2005）。特别是，CA 3被假设为支持随后在检索时完成模式的连接记忆的编码，本质上是基于过去获得的知识对现在进行预测。CA 3被认为将这些预测传递给CA 1，CA 1被定位为将来自记忆的输出与来自内嗅皮层的输入进行比较，内嗅皮层传输“感觉现实”的当前状态。为了研究CA 3和CA 1对模式完成和预测错误检测的功能贡献，我们使用高分辨率fMRI测量MTL皮层嗅周、海马旁和内嗅以及海马适当的子区域的功能反应。在有意编码（不扫描），受试者看到脸房子对。随后，受试者在3 T下进行扫描（有效TR=2s，TE= 41 ms，1.7 x 1.7 x 3 mm），同时进行线索回忆，然后进行是/否探头决策。在每个测试试验中，一个元素的研究对作为检索线索，这是由7.5秒的延迟，在此期间，受试者试图检索相关。在延迟之后，提供了一个探测器，要么是正确的关联（匹配），要么是不正确的项目（不匹配）;受试者有750 ms的时间做出是/否的回答（这种快速的回答鼓励了延迟期间的模式完成）。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The hippocampus is known to be critical for declarative memory, though the functional contributions of the subfields of human hippocampus remain underspecified. The anatomical organization of hippocampus¿¿which includes dentate gyrus, CA3, CA1, and subiculum¿¿suggests that CA3 and CA1 may differentially subserve memory-based prediction and the detection of prediction error (Lisman & Grace, 2005). In particular, CA3 is hypothesized to support the encoding of conjunctive memories that are subsequently ¿pattern completed¿ at retrieval, in essence making predictions about the present based on knowledge acquired in the past. CA3 is thought to pass these predictions to CA1, which is positioned to compare this output from memory with input from entorhinal cortex that transmits the present state of ¿sensory reality¿. To examine the functional contributions of CA3 and CA1 to pattern completion and the detection of prediction error, we used high-resolution fMRI to measure the functional response of MTL cortices¿¿perirhinal, parahippocampal, and entorhinal¿¿and the subfields of hippocampus proper. During intentional encoding (not scanned), subjects viewed face-house pairs. Subsequently, subjects were scanned at 3T (effective TR=2s, TE=41ms, 1.7 x 1.7 x 3 mm) while performing cued-recall followed by a yes/no probe decision. On each test trial, one element of a studied pair served as a retrieval cue, which was followed by a 7.5-s delay during which the subject attempted to retrieve the associate. Following the delay, a probe was presented¿¿either the correct associate (match) or an incorrect item (mismatch); subjects had 750 ms to make a yes/no response (this speeded response encouraged pattern completion during the delay period).