Examining Resting-state Functional and Structural Connectivity of the Attention Networks after Early Brain Insults

Abstract

Brain insults that occur early in life often lead to cognitive impairments, and sustained attention is highly vulnerable to the initial event as well as to the altered structural and functional brain development that follows. Sustained attention impairments are associated with neural changes in specific brain networks – default mode network (DMN) and central executive network (CEN) – that are crucial for proper attention functioning in healthy populations. Prior studies have, however, typically focused on adult cohorts, which is not applicable to understanding structural and functional changes in the developing brain. There are relatively few studies that have examined these networks in children with an early life injury with advanced quantitative neuroimaging techniques (structural magnetic resonance imaging (MRI) and functional MRI). Thus, the current thesis used these methods to investigate DMN and CEN changes following an early life brain insult in children with traumatic brain injury (TBI), epilepsy, or heterogeneous brain insults with the aim to identify shared neural changes in heterogeneous patient cohorts that underpin common attention impairments. The current thesis has reported reduced functional connectivity in the DMN regions (posterior cingulate cortex and medial prefrontal cortex) in children with TBI, and in the left parietal lobe in children with focal epilepsy as compared to controls at 2-years post-injury. Children with epilepsy however showed no differences in the structural covariance network when compared to controls. Children with heterogeneous brain insults also showed no significant functional and structural connectivity changes when imaging data were acquired in the acute post-insult period. This thesis is however limited by the lack of behavioural measures, and future studies should integrate neuropsychology and neuroimaging to better understand the relationships between the brain connectivity changes and attention deficits, therefore allowing the identification of children who would benefit most from early interventions that could improve their long-term neurocognitive outcomes.