Pacellation method based on brain cortical morphological aging trajectory in normal cohorts

The brain goes through various anatomical changes with age. These alterations are a result of ageing naturally. A more profound comprehension of these typical changes is crucial for separating them from pathogenic ones. In this study, we exhibit the ageing trajectories of cortical morphology by using cortical thickness from 55 to 85 years old. To explore the ageing hierarchical pattern, the whole cortex is divided into different regions with similar ageing trajectories. To construct the similarity matrix, we computed Pearson’s correlation coefficient between the cortical thickness of any paired vertices on the cortical surface. Then, we applied the parcellation method based on the similarity matrix on 490 normal middle-aged and old adults from 55 to 85 years old, and achieved meaningful hierarchical parcellation ageing maps based on cortical ageing trajectory. We then fit the ageing trajectory of the cortical thickness in each cluster. The results indicate that the rapid thinning regions in clusters are related to the temporal cortex and prefrontal cortices, while slowly thinning regions in clusters are related to the insula and medial occipital cortices. Importantly, our generated parcellation ageing maps indicate the hierarchical ageing patterns of normal middle-age and old adults, which is essential in disease diagnosing related to neurodegeneration and can help understand the ageing process.