Geier Kirk T, Buchsbaum Bradley R, Parimoo Shireen, Olsen Rosanna K
Rotman Research Institute, Baycrest, Toronto, Ontario, M6A 2E1, Canada; Department of Psychology, University of Toronto, Toronto, Ontario, M5T 1R8, Canada.
Neuropsychologia. 2020 Nov;148:107623. doi: 10.1016/j.neuropsychologia.2020.107623. Epub 2020 Sep 10.
A growing body of work has revealed a role for the anterior and medial dorsal thalamus in memory. Very few studies, however, have used neuroimaging to test hypotheses regarding these structures' predicted roles in associative memory encoding and retrieval. To fill this gap, our study used fMRI in a group of healthy adults as they performed a face-scene associative memory task. We are the first to report that greater deactivation of the anterior thalamus (AT) during encoding was related to subsequent memory. This finding suggests that the AT contributes to the gating of irrelevant information during memory formation. While the medial dorsal thalamus (MD) demonstrated a positive BOLD response during the memory decision, this activity was not significantly related to the ability to correctly choose the face that "matched" the paired scene, despite this region being implicated in familiarity memory. When contrasting connectivity to the medial temporal lobe between the anterior and medial dorsal thalamic nuclei, results revealed that the medial dorsal thalamus was more strongly connected to the hippocampus, perirhinal cortex, and parahippocampal cortex. However, there was no relationship between anterior or medial dorsal thalamic functional connectivity with the MTL and memory success. These results were unexpected as extant theories of the function of the AT relate to its communication with the hippocampus and theories of the MD propose its function relates to communication with the prefrontal cortex. These findings provide novel evidence for differential roles of the anterior and medial dorsal thalamic nuclei in associative memory and inform existing models of the role of the extended hippocampal system in memory.
越来越多的研究揭示了丘脑前核和背内侧丘脑在记忆中的作用。然而，很少有研究使用神经影像学来检验关于这些结构在联想记忆编码和检索中所预测作用的假设。为了填补这一空白，我们的研究在一组健康成年人执行面部-场景联想记忆任务时使用了功能磁共振成像（fMRI）。我们首次报告，编码过程中丘脑前核（AT）更强的失活与后续记忆有关。这一发现表明，丘脑前核在记忆形成过程中有助于筛选无关信息。虽然背内侧丘脑（MD）在记忆决策过程中表现出正性的血氧水平依赖（BOLD）反应，但尽管该区域与熟悉性记忆有关，这种活动与正确选择与配对场景“匹配”的面部的能力并无显著关联。当对比丘脑前核和背内侧丘脑核与内侧颞叶的连接性时，结果显示背内侧丘脑与海马体、嗅周皮质和海马旁皮质的连接更强。然而，丘脑前核或背内侧丘脑与内侧颞叶的功能连接性与记忆成绩之间并无关联。这些结果出乎意料，因为现有的丘脑前核功能理论涉及其与海马体的通信，而背内侧丘脑的理论认为其功能与与前额叶皮质的通信有关。这些发现为丘脑前核和背内侧丘脑核在联想记忆中的不同作用提供了新证据，并为扩展海马系统在记忆中作用现有的模型提供了信息。
