Primate brains display a wide range of variation in size and cerebral gyrification, leading to the appearance of novel sulci in particular groups of species. We investigated sulcal organization in the medial frontal cortex of great apes, with a particular focus on the paracingulate sulcus (PCGS). Until recently, the presence of the PCGS was thought to be a structural feature unique to the human brain. However, upon closer examination, the PCGS has been observed as a variable feature that also may appear in chimpanzee brains. To understand the evolutionary origins of the sulcal anatomy in the medial frontal cortex of apes, we examined high-resolution MRI scans for the presence or absence of the PCGS and, when present, measured its length in a sample of ape brains (chimpanzees, bonobos, gorillas, orangutans, gibbons, and siamangs). We found that the PCGS is variable in its appearance among these species, being present in 23 to 50% of great ape individuals depending on the species, but not present in gibbons or siamangs. We did not find population level hemispheric lateralization patterns or sex differences in PCGS presence across species, and we did not detect a relationship between cerebral volume and PCGS occurrence or length. Our data suggest that the PCGS is a common sulcal variant present in great apes and humans due to a shared evolutionary ancestry.
Brain Behav Evol

中文翻译：

---

Paracingulate Sulcus 是类人猿和人类共有的内侧额叶皮层的独特特征

灵长类动物的大脑在大小和大脑旋转方面表现出广泛的变化，导致特定物种群体出现新的脑沟。我们研究了类人猿内侧额叶皮层的脑沟组织，特别关注了paracingulate sulcus (PCGS)。直到最近，PCGS 的存在还被认为是人类大脑独有的结构特征。然而，经过仔细检查，PCGS 被认为是一个可变特征，也可能出现在黑猩猩的大脑中。为了了解猿内侧额叶皮层中沟解剖结构的进化起源，我们检查了高分辨率 MRI 扫描是否存在 PCGS，并在存在时测量了其在猿大脑样本（黑猩猩、倭黑猩猩、倭黑猩猩）中的长度、大猩猩、猩猩、长臂猿和暹罗）。我们发现 PCGS 在这些物种中的外观是可变的，根据物种的不同，存在于 23% 到 50% 的类人猿个体中，但不存在于长臂猿或长臂猿中。我们没有发现种群水平的半球偏侧化模式或 PCGS 在不同物种间存在的性别差异，并且我们没有检测到脑容量与 PCGS 发生或长度之间的关系。我们的数据表明，PCGS 是类人猿和人类中常见的一种常见的脑沟变异，因为它们具有共同的进化祖先。我们没有检测到脑容量与 PCGS 发生或长度之间的关系。我们的数据表明，PCGS 是类人猿和人类中常见的一种常见的脑沟变异，因为它们具有共同的进化祖先。我们没有检测到脑容量与 PCGS 发生或长度之间的关系。我们的数据表明，PCGS 是类人猿和人类中常见的一种常见的脑沟变异，因为它们具有共同的进化祖先。
大脑行为进化