Age-related changes in the endocranial capacity and surface area of ancient children from the Zaghunluq Cemetery (650-150 BCE) in Xinjiang, Northwestern China.

Early childhood is an important period for the rapid growth of the brain, which is crucial to neural connection and cognitive development. The purpose of this study is to characterize the age changes of endocasts in ancient children in Northwestern China (2600-2100 BP) to enrich our understanding of brain growth. 28 crania of ancient children excavated from the Zaghunluq cemetery were analyzed using endocasts generated from CT images. The endocast features of age-related changes were assessed by comparing the endocranial volume (cranial capacity), the intracranial surface area, and their ratios among different age groups: 2, 3-5, 6-7, 8-10, 12-15, and 17-19 years. The results demonstrated that with the increase of age, the volume and the surface area of children's endocasts seem to increase between age groups. The growth spurt periods of endocranial volume are 3-5 years old and 8-10 years old, and the growth spurt period of endocranial surface area is 3-5 years old, similar to the patterns in modern children. The increase of endocast surface area is smaller than that of volume, resulting in an overall increase in the ratio of endocranial volume to surface area, indicating a trend of gradual globularization of the brain.