Functional brain networks are interconnected brain regions that flexibly coordinate their activity to support cognitive demands (Fair et al., 2009). Functional brain connectivity describes a statistical dependency between the activities recorded at spatially distinct brain regions (Friston, 2009). Changes in the pattern of connections and level of activation in functional brain networks are thought to occur across development (Taylor, Donner, & Pang, 2012) but the nature of these changes and their relationship to cognitive development have yet to be delineated clearly. This thesis seeks to deepen our understanding of the development of functional brain connectivity across the age range 9-25 years. We used magnetoencephalography in conjunction with canonical correlation analysis to explore functional connectivity via amplitude-amplitude envelope correlations in 110 datasets (39 working memory, 33 relevance modulation (attention processing) and 38 resting state). At the core of this thesis, we have presented novel findings that show non-linear functional connectivity changes across development, with an increase from childhood (age 9-12) to late adolescence (age 17-20) followed by a reduction into young adulthood (age 21-25), resembling an inverted-U-shaped trajectory at least in the females included in this study. Whilst there are subtle yet statistically significant differences in how the functional connectivity profile from 1-100 Hz is modulated by different factors, the overall pattern of functional connectivity development appears to be remarkably consistent across cognitive demands and networks. Critically, this work is the first example of such findings and suggests that functional brain networks supporting higher order cognitive function are not alone in undergoing functional development; sensory networks that reach structural maturity early on in life also undergo functional development from age 9 to 25.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:668618 |
| Date | January 2015 |
| Creators | Smith, Helen Joanna Fabienne |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/28421/ |
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