Developmental Connectomics from Infancy through Early Childhood

Abstract

The human brain undergoes rapid growth in both structure and function from infancy through early childhood, and this significantly influences cognitive and behavioral development in later life. A newly emerging research framework, developmental connectomics, provides unprecedented opportunities for exploring the developing brain through non-invasive mapping of structural and functional connectivity patterns. Within this framework, we review recent neuroimaging and neurophysiological studies investigating connectome development from 20 postmenstrual weeks to 5 years of age. Specifically, we highlight five fundamental principles of brain network development during the critical first years of life, emphasizing strengthened segregation/integration balance, a remarkable hierarchical order from primary to higher-order regions, unparalleled structural and functional maturations, substantial individual variability, and high vulnerability to risk factors and developmental disorders.

Keywords: connectome; developmental disorder; functional connectivity; graph theory; segregation and integration; structural connectivity.

Figure 1. Research summary of developmental connectomics from infancy to early childhood

Summary of the developmental brain connectomic studies from early infancy to childhood with advanced neuroimaging and neurophysiological techniques. This figure represents the literature search results on Pubmed (www.ncbi.nlm.nih.gov/pubmed) with keywords “connectivity” OR “network” OR “connectome” combined with “early development” OR “infant” OR “baby”. A total of 112 relevant studies published between 2007 and 2017 are included here. The publications are summarized and plotted as distribution histograms according to their publication years (a), age span (b), imaging modality (c) as well as pie charts regarding sample size (d), sample design (e), and scanning status (f). sMRI, structural MRI; dMRI, diffussion MRI; fMRI, functional MRI; EEG, electroencephalography; fNIRS, functional near-infrared spectroscopy.

Figure 2. Hypothetic models of the brain connectome development from infancy to early childhood

(a) Presenting the hypothetic developmental model of information segregation and integration in the brain networks. (b) Presenting the hypothetic developmental model from primary regions to high-order association regions. (c) Presenting the hypothetic developmental model of structural and functional brain connectomes.

Figure I