The cortex has a characteristic layout with specialized functional areas forming distributed large-scale networks. However, substantial work shows striking variation in this organization across people, which relates to differences in behavior. While most previous work treats individual differences as linked to boundary shifts between the borders of regions, here we show that cortical ‘variants’ also occur at a distance from their typical position, forming ectopic intrusions. Both ‘border’ and ‘ectopic’ variants are common across individuals, but differ in their location, network associations, properties of subgroups of individuals, activations during tasks, and prediction of behavioral phenotypes. Border variants also track significantly more with shared genetics than ectopic variants, suggesting a closer link between ectopic variants and environmental influences. This work argues that these two dissociable forms of variation—border shifts and ectopic intrusions—must be separately accounted for in the analysis of individual differences in cortical systems across people.

皮层具有独特的布局，具有专门的功能区域，形成分布式的大规模网络。然而，大量研究表明，该组织中不同人员之间存在显着差异，这与行为差异有关。虽然大多数先前的工作将个体差异视为与区域边界之间的边界变化有关，但在这里我们表明，皮质“变异”也发生在远离其典型位置的地方，形成异位侵入。 “边界”和“异位”变异在个体中都很常见，但在位置、网络关联、个体亚组的属性、任务期间的激活以及行为表型的预测方面有所不同。边界变异也比异位变异更多地追踪共享遗传学，这表明异位变异和环境影响之间的联系更紧密。这项工作认为，在分析人们皮质系统的个体差异时，必须分别考虑这两种可分离的变异形式——边界转移和异位入侵。