title: Global and regional cortical connectivity maturation index (CCMI) of developmental human brain with quantification of short-range association tracts.
abstract: From early childhood to adulthood, synaptogenesis and synaptic pruning continuously reshape the structural architecture and neural connection in developmental human brains. Disturbance of the precisely balanced strengthening of certain axons and pruning of others may cause mental disorders such as autism and schizophrenia. To characterize this balance, we proposed a novel measurement based on cortical parcellation and diffusion MRI (dMRI) tractography, a cortical connectivity maturation index (CCMI). To evaluate the spatiotemporal sensitivity of CCMI as a potential biomarker, dMRI and T1weighted datasets of 21 healthy subjects 2-25 years were acquired. Brain cortex was parcellated into 68 gyral labels using T1weighted images, then transformed into dMRI space to serve as the seed region of interest for dMRI-based tractography. Cortico-cortical association fibers initiated from each gyrus were categorized into long- and short-range ones, based on the other end of fiber terminating in non-adjacent or adjacent gyri of the seed gyrus, respectively. The regional CCMI was defined as the ratio between number of short-range association tracts and that of all association tracts traced from one of 68 parcellated gyri. The developmental trajectory of the whole brain CCMI follows a quadratic model with initial decreases from 2 to 16 years followed by later increases after 16 years. Regional CCMI is heterogeneous among different cortical gyri with CCMI dropping to the lowest value earlier in primary somatosensory cortex and visual cortex while later in the prefrontal cortex. The proposed CCMI may serve as sensitive biomarker for brain development under normal or pathological conditions.
authors.affiliation: Department of Radiology, Children's Hospital of Philadelphia, PA, United States.
authors.forename: Minhui
authors.initials: M
authors.lastname: Ouyang
authors.affiliation: Department of Radiology, Children's Hospital of Philadelphia, PA, United States.
authors.forename: Tina
authors.initials: T
authors.lastname: Jeon
authors.affiliation: Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, United States.
authors.forename: Virendra
authors.initials: V
authors.lastname: Mishra
authors.affiliation: Department of Electronic Engineering, Tsinghua University, Beijing, China.
authors.forename: Haixiao
authors.initials: H
authors.lastname: Du
authors.affiliation: Department of Electronic Engineering, Tsinghua University, Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Radiology, Beijing Children's Hospital, Capital Medical University, Beijing, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Radiology, Children's Hospital of Philadelphia, PA, United States; Department of Radiology, Perelman School of Medicine, University of Pennsylvania, PA, United States.
authors.forename: Hao
authors.initials: H
authors.lastname: Huang
keywords: cortical connectivity; development; diffusion MRI; maturation index; short-range association tracts