Bruno Ariane, Lothmann Kimberley, Bludau Sebastian, Mohlberg Hartmut, Amunts Katrin
Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany.
Cécile and Oskar Vogt Institute for Brain Research, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
Front Neuroimaging. 2024 Feb 22;3:1339244. doi: 10.3389/fnimg.2024.1339244. eCollection 2024.
Areas of the dorsolateral prefrontal cortex (DLPFC) are part of the frontoparietal control, default mode, salience, and ventral attention networks. The DLPFC is involved in executive functions, like working memory, value encoding, attention, decision-making, and behavioral control. This functional heterogeneity is not reflected in existing neuroanatomical maps. For example, previous cytoarchitectonic studies have divided the DLPFC into two or four areas. Macroanatomical parcellations of this region rely on gyri and sulci, which are not congruent with cytoarchitectonic parcellations. Therefore, this study aimed to provide a microstructural analysis of the human DLPFC and 3D maps of cytoarchitectonic areas to help address the observed functional variability in studies of the DLPFC. We analyzed ten human post-mortem brains in serial cell-body stained brain sections and mapped areal boundaries using a statistical image analysis approach. Five new areas (i.e., SFG2, SFG3, SFG4, MFG4, and MFG5) were identified on the superior and middle frontal gyrus, i.e., regions corresponding to parts of Brodmann areas 9 and 46. Gray level index profiles were used to determine interregional cytoarchitectural differences. The five new areas were reconstructed in 3D, and probability maps were generated in commonly used reference spaces, considering the variability of areas in stereotaxic space. Hierarchical cluster analysis revealed a high degree of similarity within the identified DLPFC areas while neighboring areas (frontal pole, Broca's region, area 8, and motoric areas) were separable. Comparisons with functional imaging studies revealed specific functional profiles of the DLPFC areas. Our results indicate that the new areas do not follow a simple organizational gradient assumption in the DLPFC. Instead, they are more similar to those of the ventrolateral prefrontal cortex (Broca's areas 44, 45) and frontopolar areas (Fp1, Fp2) than to the more posterior areas. Within the DLPFC, the cytoarchitectonic similarities between areas do not seem to follow a simple anterior-to-posterior gradient either, but cluster along other principles. The new maps are part of the publicly available Julich Brain Atlas and provide a microstructural reference for existing and future imaging studies. Thus, our study represents a further step toward deciphering the structural-functional organization of the human prefrontal cortex.
背外侧前额叶皮质（DLPFC）区域是额顶叶控制、默认模式、突显和腹侧注意网络的一部分。DLPFC参与执行功能，如工作记忆、价值编码、注意力、决策和行为控制。这种功能异质性并未反映在现有的神经解剖图谱中。例如，先前的细胞构筑学研究已将DLPFC分为两个或四个区域。该区域的大体解剖分区依赖于脑回和脑沟，这与细胞构筑分区并不一致。因此，本研究旨在对人类DLPFC进行微观结构分析，并绘制细胞构筑区域的三维图谱，以帮助解决在DLPFC研究中观察到的功能变异性问题。我们分析了10个死后人类大脑的连续细胞体染色脑切片，并使用统计图像分析方法绘制区域边界。在额上回和额中回，即对应于布罗德曼区域9和46部分的区域，确定了五个新区域（即SFG2、SFG3、SFG4、MFG4和MFG5）。灰度指数剖面图用于确定区域间的细胞构筑差异。考虑到立体定向空间中区域的变异性，在常用的参考空间中对这五个新区域进行了三维重建，并生成了概率图谱。层次聚类分析显示，在确定的DLPFC区域内具有高度相似性，而相邻区域（额极、布洛卡区、8区和运动区）是可分离的。与功能成像研究的比较揭示了DLPFC区域的特定功能特征。我们的结果表明，新区域在DLPFC中并不遵循简单的组织梯度假设。相反，它们与腹外侧前额叶皮质（布洛卡区44、45）和额极区域（Fp1、Fp2）的区域更相似，而与更靠后的区域不同。在DLPFC内，区域间的细胞构筑相似性似乎也不遵循简单的从前到后的梯度，而是按照其他原则聚类。这些新图谱是公开可用的朱利希脑图谱的一部分，为现有和未来的成像研究提供了微观结构参考。因此，我们的研究代表了朝着破译人类前额叶皮质的结构-功能组织迈出的又一步。
