Abstract：
The inferior frontal sulcus is conceptualized as the landmark delineating ventro-from dorsolateral prefrontal cortex. Functional imaging studies report activations within the sulcus during tasks addressing cognitive control and verbal working memory, while their microstructural correlates are not well defined. Existing microstructural maps, e.g., Brodmann\'s map, do not distinguish separate areas within the sulcus. We identified six new areas in the inferior frontal sulcus and its junction to the precentral sulcus, ifs1-4, ifj1-ifj2, by combined cytoarchitectonic analysis and receptor autoradiography. A hierarchical cluster analysis of receptor densities of these and neighbouring prefrontal areas revealed that they form a distinct cluster within the prefrontal cortex. Major interhemispheric differences were found in both cyto- and receptorarchitecture. The function of cytoarchitectonically identified areas was explored by comparing probabilistic maps of the areas in stereotaxic space with their functions and co-activation patterns as analysed by means of a coordinate-based meta-analysis. We found a bilateral involvement in working memory, as well as a lateralization of different language-related processes to the left hemisphere, and of music processing and attention to the right-hemispheric areas. Particularly ifj2 might act as a functional hub between the networks. The cytoarchitectonic maps and receptor densities provide a powerful tool to further elucidate the function of these areas. The maps are available through the Human Brain Atlas of the Human Brain Project and serve in combination with the information on the cyto- and receptor architecture of the areas as a resource for brain models and simulations.
摘要：
下额叶沟被概念化为从背外侧前额叶皮层描绘腹侧的标志。功能成像研究报告了在处理认知控制和言语工作记忆的任务期间沟内的激活，而它们的微观结构相关性并不明确。现有的显微结构图，例如，Brodmann的地图,不要区分沟内的单独区域。我们在下额沟及其与中央前沟的交界处发现了六个新区域，ifs1-4，ifj1-ifj2，通过联合细胞结构分析和受体放射自显影。对这些和邻近前额叶区域的受体密度进行的分层聚类分析显示，它们在前额叶皮层内形成了一个独特的簇。在细胞和受体结构中都发现了半球间的主要差异。通过比较立体定位空间中区域的概率图及其功能和共激活模式，探索了细胞结构识别区域的功能。我们发现工作记忆有双边参与，以及将不同的语言相关过程侧向化到左半球，以及对右半球区域的音乐处理和关注。特别是ifj2可能充当网络之间的功能集线器。细胞结构图和受体密度为进一步阐明这些区域的功能提供了强大的工具。这些地图可通过人脑计划的人脑图集获得，并与有关该区域的细胞和受体结构的信息相结合，作为大脑模型和模拟的资源。
