On the Spectrum

Chapter 5
ABSTRACT
Autism spectrum disorder is often studied with little context of typical brain development. In
addition, most functional connectivity studies operate under the assumption that connectivity
remains static over multiple minutes. We hypothesized that relaxing this stationarity
assumption would reveal novel features of both autism and typical brain development. We
employed a ‘chronnectomic’ (recurring, time-varying patterns of connectivity) approach to
evaluate transient states of connectivity using resting-state functional MRI in a sample of 774
6-to-10 year-old children. Whole-brain dynamic connectivity was evaluated using a sliding
window technique, and revealed four transient states. Inter-domain connectivity increased
with age in modularized dynamic states, illustrating an important pattern of connectivity
associated with the developing brain. Furthermore, we demonstrate that higher levels of
autistic traits were associated with more time spent in a globally disconnected state. These
results provide a road map to the chronnectomic organization of the brain and also suggest
that children with autistic traits exhibit delayed characteristics of functional brain maturation.
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