Kulkarni Mrinmayi, Jiang Lydia, Robin Jessica, Choi Jung Won, Buchsbaum Bradley R, Olsen Rosanna K
Baycrest Academy of Research and Education, Toronto, Ontario, Canada.
University of Toronto.
J Cogn Neurosci. 2025 Jul 8:1-25. doi: 10.1162/jocn.a.73.
A hallmark feature of episodic memory is the ability to flexibly recombine information across episodes to form new associations and guide behavior. This process, termed associative inference, relies on the hippocampus and surrounding medial temporal lobe (MTL) subregions. We previously found that cross-episode binding was improved when episodes were linked by scenes rather than by faces or objects. Here, we tested whether differential recruitment of category-sensitive MTL subregions underlies these behavioral differences. Participants completed study-test phases of the Associative Inference in Memory task, while undergoing fMRI scanning. During the study phase, they encoded overlapping AB and BC pairs. A and C items were always objects. The linking B item was either a face or a scene. At test, memory for the direct (AB, BC) and indirect associations (inferred AC) was tested. Category sensitivity in MTL subregions was tested using an independent functional localizer and the low integration (AB) trials from the study phase of the Associative Inference in Memory task. Within the MTL, no subregions exhibited face sensitivity. The anterior hippocampal head, anterolateral and posteromedial entorhinal cortices, and parahippocampal cortex were identified as scene sensitive. Although accuracy of the indirect inferences did not differ between pairs linked by faces and scenes, MTL subregion recruitment differed across categories. Scene-sensitive subregions in MTL cortex (anterolateral entorhinal cortex, posteromedial entorhinal cortex, and parahippocampal cortex), but not the hippocampus (anterior hippocampal head), were recruited to support associative inference for faces during encoding. These findings suggest that regions in MTL cortex identified as scene sensitive here may be involved in integrating disparate elements of episodes into coherent representations, and may be recruited for nonscene stimuli when integration demands during encoding are high (e.g., during associative inference).
情景记忆的一个标志性特征是能够灵活地跨情景重新组合信息，以形成新的关联并指导行为。这个过程被称为联想推理，依赖于海马体和周围的内侧颞叶（MTL）亚区域。我们之前发现，当情景通过场景而不是面孔或物体联系起来时，跨情景绑定会得到改善。在这里，我们测试了类别敏感的MTL亚区域的差异募集是否是这些行为差异的基础。参与者在进行功能磁共振成像扫描时完成了记忆任务中的联想推理的学习-测试阶段。在学习阶段，他们对重叠的AB和BC对进行编码。A和C项始终是物体。连接的B项要么是面孔，要么是场景。在测试时，对直接（AB、BC）和间接关联（推断的AC）的记忆进行了测试。使用独立的功能定位器和记忆任务中联想推理学习阶段的低整合（AB）试验来测试MTL亚区域的类别敏感性。在MTL内，没有亚区域表现出对面孔的敏感性。海马体前部、前外侧和后内侧内嗅皮质以及海马旁皮质被确定为对场景敏感。尽管通过面孔和场景连接的对之间间接推理的准确性没有差异，但MTL亚区域的募集在不同类别之间存在差异。MTL皮质（前外侧内嗅皮质、后内侧内嗅皮质和海马旁皮质）中对场景敏感的亚区域，而不是海马体（海马体前部），在编码过程中被募集来支持对面孔的联想推理。这些发现表明，这里确定为对场景敏感的MTL皮质区域可能参与将情景的不同元素整合为连贯的表征，并且在编码期间整合需求较高时（例如在联想推理期间）可能被募集用于非场景刺激。
