PDF(Pubmed)
Abstract：
The inferior frontal sulcus (ifs) is a prominent sulcus on the lateral frontal cortex, separating the middle frontal gyrus from the inferior frontal gyrus. The morphology of the ifs can be difficult to distinguish from adjacent sulci, which are often misidentified as continuations of the ifs. The morphological variability of the ifs and its relationship to surrounding sulci were examined in 40 healthy human subjects (i.e., 80 hemispheres). The sulci were identified and labeled on the native cortical surface meshes of individual subjects, permitting proper intra-sulcal assessment. Two main morphological patterns of the ifs were identified across hemispheres: in Type I, the ifs was a single continuous sulcus, and in Type II, the ifs was discontinuous and appeared in two segments. The morphology of the ifs could be further subdivided into nine subtypes based on the presence of anterior and posterior sulcal extensions. The ifs was often observed to connect, either superficially or completely, with surrounding sulci, and seldom appeared as an independent sulcus. The spatial variability of the ifs and its various morphological configurations were quantified in the form of surface spatial probability maps which are made publicly available in the standard fsaverage space. These maps demonstrated that the ifs generally occupied a consistent position across hemispheres and across individuals. The normalized mean sulcal depths associated with the main morphological types were also computed. The present study provides the first detailed description of the ifs as a sulcal complex composed of segments and extensions that can be clearly differentiated from adjacent sulci. These descriptions, together with the spatial probability maps, are critical for the accurate identification of the ifs in anatomical and functional neuroimaging studies investigating the structural characteristics and functional organization of this region in the human brain.
摘要：
下额叶沟(ifs)是位于外侧额叶皮质的突出沟,将额中回与额下回分开。ifs的形态可能很难与相邻的沟区分开来，通常被错误地识别为ifs的延续。在40名健康人类受试者中检查了ifs的形态变异性及其与周围沟的关系（即80个半球)。在个体受试者的天然皮质表面网格上识别并标记沟，允许适当的沟内评估。跨半球确定了ifs的两个主要形态模式：I型，ifs是一个连续的沟，在第二类中，ifs是不连续的，出现在两个部分。根据前后沟延伸的存在，ifs的形态可以进一步细分为9种亚型。人们经常观察到ifs连接，无论是表面上还是完全，周围的沟，很少出现作为一个独立的沟。ifs的空间变异性及其各种形态构型以表面空间概率图的形式进行了量化，这些图在标准fsaverage空间中公开提供。这些地图表明，ifs通常在半球和个体之间占据一致的位置。还计算了与主要形态类型相关的归一化平均沟深。本研究提供了对ifs的首次详细描述，它是由节段和延伸部分组成的沟复合体，可以与相邻沟明显区分开。这些描述，连同空间概率图，对于在解剖和功能神经影像学研究中准确识别ifs至关重要，该研究调查了人脑中该区域的结构特征和功能组织。
