Towards the “Baby Connectome”: Mapping the Structural Connectivity of the Newborn Brain

Abstract

Defining the structural and functional connectivity of the human brain (the human “connectome”) is a basic challenge in neuroscience. Recently, techniques for noninvasively characterizing structural connectivity networks in the adult brain have been developed using diffusion and high-resolution anatomic MRI. The purpose of this study was to establish a framework for assessing structural connectivity in the newborn brain at any stage of development and to show how network properties can be derived in a clinical cohort of six-month old infants sustaining perinatal hypoxic ischemic encephalopathy (HIE). Two different anatomically unconstrained parcellation schemes were proposed and the resulting network metrics were correlated with neurological outcome at 6 months. Elimination and correction of unreliable data, automated parcellation of the cortical surface, and assembling the large-scale baby connectome allowed an unbiased study of the network properties of the newborn brain using graph theoretic analysis. In the application to infants with HIE, a trend to declining brain network integration and segregation was observed with increasing neuromotor deficit scores.

The emergence of functional architecture during early brain development

“…With all major white matter tracts being in place by the end of normal gestation, it is not surprising that structural connectome studies -examining whole brain connectivity on a macroscopic level (Box 1) -have revealed structural network organization in the neonatal brain to show great similarity to the adult human brain Brown et al, 2014;Ratnarajah et al, 2013;Shi et al, 2012;Tymofiyeva et al, 2012;van den Heuvel et al, 2014;Yap et al, 2011). Key features of adult connectome architecture have been demonstrated in the neonatal brain, including a small world organization -combining local specialization with long-range efficiency -, a modular topology -meaning that the network constitutes smaller subnetworks for specialized information processing -, and a heavy tailed degree distribution with brain regions which show the highest number of connections forming a central core or 'rich club' (Box 1).…”

Structural network analysis of brain development in young preterm neonates

“…Some other recent works have focused on the examination of the structural connectome of young infants by performing tractography between numerous anatomical regions in the brain [3,41,50,52,53,58,54]. Takahashi et al examined results of full-brain tractography qualitatively and described trends across postmortem infants between 17 and 40 weeks [50].…”

“…Yap et al examined the development of connectomes in young children, across a range of ages between 2 weeks and 2 years, using measures of network integration and segregation [58]. Tymofiyeva et al used an atlas-free approach to analyze connectome development in preterm infants, children and adults, also employing network measures to capture topological changes [52,53]. Very recently, Ball et al studied a specific network measure known as rich-club organization in a cohort of preterm infants [2].…”

Diffusion magnetic resonance imaging for Brainnetome: A critical review

“…Brainnetome has sparked promising research and clinical applications for both developmental and neuropsychiatric conditions [2,[5][6][7][8][9] . The emerging Brainnetome era needs multidisciplinary collaboration [12] .…”

“…To date, it is the only non-invasive method for revealing the micro-geometry of nervous tissues and exploring white matter fiber connectivities in living human subjects. Increasing numbers of reports reveal altered networks of white matter microstructure (WMM) in neuropsychiatric disorders, such as MDD [4] , bipolar disorder [15] , AD [16] , schizophrenia [17] and epilepsy [18] , as well as in development [7,8] and healthy aging [9] .…”