Examining the Association Between Preterm Birth and Social-Emotional Functioning: The Role of the Amygdala and the Exploration of Other Contributing Factors

The amygdala is a key element of the limbic system which plays a critical role in emotional processing. Atypical development of the amygdala and the projections to other structures within the limbic system may underlie social-emotional difficulties. The amygdala demonstrates exponential growth throughout childhood, although limited research has examined its detailed growth trajectory early in life and therefore a thorough understanding of typical and atypical development and the association with later social-emotional functioning is lacking. Preterm birth (weeks' gestation) is highly prevalent and is associated with many developmental delays in addition to impairments in social-emotional functioning. These challenges can be evident early on in life which is suggestive of early brain adaptations. This dissertation consists of three chapters that examine the development of the amygdala and its correlation with later social-emotional outcomes. Chapter two explores this in a large cross-cohort sample of fetuses and infants born both preterm and full-term. Whereas Chapters three and four examine this in preterm populations. Results from Chapter two suggest that there are both sex and laterality differences in the development of the amygdala and that amygdala volumes are predictive of later social and communicative outcomes. Chapter three found both subnuclei volumes and functional connectivity surrounding the amygdala to be predictive of later social-emotional functioning in childhood. Lastly, results from Chapter four were indicative of associations between amygdala volumes in infancy and social-emotional functioning at preschool age, suggesting that these neurological adaptations are present as early as infancy. The results also identified procedural pain as a moderator of this relationship. The research presented provides evidence of neurological based biomarkers in both populations of typically developing and preterm children that can used in identifying those at risk of social-emotional difficulties. This is particularly important for children born preterm, given their higher likelihood of difficulties in these areas. Identifying these differences as early as infancy, is promising for the effectiveness of early intervention in improving these symptoms. Labelling pain as a moderating factor and identifying sensitive windows in which it is most impactful can guide clinical approaches to pain management and care in infancy.