title: The influence of preterm birth on the developing thalamocortical connectome.
abstract: BACKGROUND
  Defining connectivity in the human brain signifies a major neuroscientific goal. Advanced imaging techniques have enabled the non-invasive tracing of brain networks to define the human connectome on a millimetre-scale. During early development, the brain undergoes significant changes that are likely represented in the developing connectome, and preterm birth represents a significant environmental risk factor that impacts negatively on early cerebral development. Using tractography to comprehensively map the connections of the thalamocortical unit, we aim to demonstrate that premature extrauterine life due to preterm delivery results in significantly decreased thalamocortical connectivity in the developing human neonate.
  
  
  METHODS
  T1- and T2-weighted magnetic resonance images and 32-direction diffusion tensor images were acquired from 18 healthy term-born neonates (median gestational age: 41(+3)) and 47 preterm infants (median gestational age: 28(+3)) scanned at term-equivalent age. Using a novel processing pipeline for tracing connections in the neonatal brain we map and compare the thalamocortical macro-connectome between groups.
  
  
  RESULTS
  We demonstrate that connections between the thalamus and the frontal cortices, supplementary motor areas, occipital lobe and temporal gyri are significantly diminished in preterm infants (FDR-corrected, p < .001).
  
  
  CONCLUSIONS
  This supports the hypothesis that the thalamocortical system is vulnerable following preterm birth and the tractographic framework presented represents a method for analysing system connectivity that can be readily applied to other populations and neural systems.
authors.affiliation: Centre for the Developing Brain, Division of Imaging Sciences & Biomedical Engineering, King's College London, London, UK.
authors.forename: Gareth
authors.initials: G
authors.lastname: Ball
authors.forename: James P
authors.initials: JP
authors.lastname: Boardman
authors.forename: Paul
authors.initials: P
authors.lastname: Aljabar
authors.forename: Anand
authors.initials: A
authors.lastname: Pandit
authors.forename: Tomoki
authors.initials: T
authors.lastname: Arichi
authors.forename: Nazakat
authors.initials: N
authors.lastname: Merchant
authors.forename: Daniel
authors.initials: D
authors.lastname: Rueckert
authors.forename: A David
authors.initials: AD
authors.lastname: Edwards
authors.forename: Serena J
authors.initials: SJ
authors.lastname: Counsell
mesh_terms: D001931:Brain Mapping; D002540:Cerebral Cortex / Q000254:growth & development* / Q000502:physiology*; D063132:Connectome; D003627:Data Interpretation, Statistical; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D017352:Echo-Planar Imaging; D004777:Environment; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000254:growth & development* / Q000502:physiology*; D047928:Premature Birth; D013788:Thalamus / Q000254:growth & development* / Q000502:physiology*