During the third trimester of human brain development, the cerebral cortex undergoes dramatic surface expansion and folding. Physical models suggest that relatively rapid growth of the cortical gray matter helps drive this folding, and structural data suggest that growth may vary in both space (by region on the cortical surface) and time. In this study, we propose a unique method to estimate local growth from sequential cortical reconstructions. Using anatomically constrained multimodal surface matching (aMSM), we obtain accurate, physically guided point correspondence between younger and older cortical reconstructions of the same individual. From each pair of surfaces, we calculate continuous, smooth maps of cortical expansion with unprecedented precision. By considering 30 preterm infants scanned two to four times during the period of rapid cortical expansion (28–38 wk postmenstrual age), we observe significant regional differences in growth across the cortical surface that are consistent with the emergence of new folds. Furthermore, these growth patterns shift over the course of development, with noninjured subjects following a highly consistent trajectory. This information provides a detailed picture of dynamic changes in cortical growth, connecting what is known about patterns of development at the microscopic (cellular) and macroscopic (folding) scales. Since our method provides specific growth maps for individual brains, we are also able to detect alterations due to injury. This fully automated surface analysis, based on tools freely available to the brain-mapping community, may also serve as a useful approach for future studies of abnormal growth due to genetic disorders, injury, or other environmental variables.

在人类大脑发育的第三阶段，大脑皮层经历剧烈的表面扩张和折叠。物理模型表明，皮质灰质相对快速的生长有助于推动这种折叠，而结构数据表明，生长可能在空间（按皮质表面的区域）和时间上有所不同。在这项研究中，我们提出了一种独特的方法来估计连续皮质重建的局部生长。使用解剖学约束的多模态表面匹配（aMSM），我们获得了同一个体的年轻和年长皮质重建之间准确的、物理引导的点对应关系。从每一对表面，我们以前所未有的精度计算出连续、平滑的皮质扩张图。通过考虑 30 名早产儿在皮质快速扩张期间（月经后 28-38 周）扫描了 2 至 4 次，我们观察到皮质表面生长的显着区域差异，这与新褶皱的出现一致。此外，这些生长模式在发育过程中会发生变化，未受伤的受试者遵循高度一致的轨迹。这些信息提供了皮质生长动态变化的详细图片，将微观（细胞）和宏观（折叠）尺度的发育模式联系起来。由于我们的方法为个体大脑提供了特定的生长图，因此我们还能够检测由于受伤而引起的变化。这种完全自动化的表面分析基于大脑绘图界免费提供的工具，也可以作为未来研究由于遗传性疾病、损伤或其他环境变量引起的异常生长的有用方法。