Department of Functional Anatomy, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
Department of Functional Anatomy, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
Neuroscience. 2021 Jul 1;466:173-185. doi: 10.1016/j.neuroscience.2021.05.009. Epub 2021 May 18.
The precuneus, involved in various cognitive processes, is considered to form the midline core of the default mode network (DMN), while the medial temporal lobe (MTL) is a subsystem of the DMN. Until now, the anatomical study of the precuneus-MTL connection is limited in humans. One possible reason is the precuneus' territory of the posteromedial cortex (PMC) is inconsistent across studies. The primary purpose of this study is to investigate the structural connectivity (SC) of precuneus-MTL, focusing on its anatomical organization using the Human Connectome Project Multi-modal Parcellation (HCP MMP) atlas. We first conducted the quantitative tractography analyses using the HCP dataset. The major streamlines originated from the posterior precuneus and were projected to the MTL extensively. Next, to complement the tractography data, we conducted the white matter dissection in the post-mortem human brain. We observed the major fiber bundles arise from the posterior precuneus extending to the anterior parahippocampal gyrus, which could support our tractography results. Then we analyzed the relationship between SC and resting-state functional connectivity (rsFC) of the precuneus-MTL. Although the SC-rsFC correlation was scarce on the whole, the posterior precuneus (POS2, 7Pm, 7m) showed a relatively high correlation (r = 0.38349, p < 0.05) with the posterior MTL (PreS, H, ProS, PHA1, PHA2). Our findings suggest the posterior precuneus is highly connected to MTL structurally, which could have an effect on the resting-state functional connectivity. In addition, the precuneus might consist of the heterogeneous connectivity-based subdivisions.
楔前叶参与了各种认知过程，被认为构成默认模式网络（DMN）的中线核心，而内侧颞叶（MTL）是 DMN 的一个子系统。到目前为止，对楔前叶-内侧颞叶连接的解剖学研究在人类中是有限的。一个可能的原因是，楔前叶的后内侧皮质（PMC）区域在不同的研究中不一致。本研究的主要目的是使用人类连接组计划多模态分区（HCP MMP）图谱研究楔前叶-内侧颞叶的结构连接（SC），重点关注其解剖组织。我们首先使用 HCP 数据集进行了定量轨迹分析。主要的束流起源于后楔前叶，并广泛投射到 MTL。接下来，为了补充轨迹数据，我们在死后人脑上进行了白质解剖。我们观察到主要的纤维束从后楔前叶延伸到前海马旁回，这可以支持我们的轨迹结果。然后，我们分析了 SC 与楔前叶-内侧颞叶静息态功能连接（rsFC）之间的关系。尽管整体上 SC-rsFC 相关性很少，但后楔前叶（POS2、7Pm、7m）与后内侧颞叶（PreS、H、ProS、PHA1、PHA2）之间表现出相对较高的相关性（r=0.38349，p<0.05）。我们的发现表明，楔前叶在结构上与 MTL 高度连接，这可能对静息态功能连接有影响。此外，楔前叶可能由具有异质连接的细分组成。
