Presented at the Neonatal Society 2014 Spring Meeting.
Toulmin H1, Beckmann C2, Nongena P3, Ederies A3, Counsell S1, Kennea N4, Arichi T1, Tusor N1, Makropoulos A1,3, Rutherford M1, Azzopardi D1, Gonzales-Cinca N3, Edwards AD1
1 Centre for the Developing Brain, King’s College, London, UK
2 Donders Institute, Radboud University Nijmegen, Netherlands
3 Faculty of Medicine, Imperial College London, UK
4 St Georges Hospital, London UK
Background: Thalamocortical projections are believed to develop rapidly during the late preterm period and may be influenced by premature birth. We used resting state functional connectivity magnetic resonance imaging (fcMRI) to assess functional thalamocortical connectivity and to test the hypothesis that infants with longer premature exposure to the extrauterine environment show less functional thalamocortical connectivity.
Methods: This study was funded by the Wellcome Trust, Medical Research Council and the National Institute of Health Research, and approved by the National Research Ethics Service. Written consent was obtained in each case and infants were sedated with oral chloral hydrate. Single shot echo planar imaging data were collected from preterm and term infants without overt pathology on T2 weighted MR images. Images were registered to a bespoke template, and we applied group independent component analysis and dual regression to identify networks of coherent Blood Oxygen-Level Dependent signals (BOLD) activity (1).
Results: Data were acquired from 66 infants between 38 and 44 weeks gestational age: 20 born between 24 and 28 weeks; 27 between 29 and 32 weeks; and 19 after 38 weeks. Voxel-wise correlations between cortical regions and the thalamus (using fsl-sbca) showed that each cortical region had dominant connectivity to well-defined and predictable thalamic targets. Using a general linear model we showed that in infants born prematurely the magnitude of thalamocortical connectivity was significantly reduced between the thalamus and insula-fronto-parietal network, anterior cingulate and dorso-lateral prefrontal cortex; the strength of thalamic connectivity with sensory-motor, visual and auditory networks was not related to prematurity (threshold-free cluster enhancement; family-wise error rate correction; p < 0.05)
Conclusion: Connectivity between thalamus and primary sensory cortices was not related to the degree of prematurity, but cortical structures associated with integrative cognitive functions showed reduced connectivity with the thalamus in infants born preterm.
Corresponding author: Hilary.Toulmin@kcl.ac.uk
1. Beckmann, C.F. (2005), ‘Investigations into resting-state connectivity using independent component analysis’, Philosophical Transactions of the Royal Society, May 29; 360(1457): 1001-1013.