The emergence of a functionally flexible brain during early infancy

Abstract

Adult brains are functionally flexible, a unique characteristic that is thought to contribute to cognitive flexibility. While tools to assess cognitive flexibility during early infancy are lacking, we aimed to assess the spatiotemporal developmental features of “neural flexibility” during the first 2 y of life. Fifty-two typically developing children 0 to 2 y old were longitudinally imaged up to seven times during natural sleep using resting-state functional MRI. Using a sliding window approach, MR-derived neural flexibility, a quantitative measure of the frequency at which brain regions change their allegiance from one functional module to another during a given time period, was used to evaluate the temporal emergence of neural flexibility during early infancy. Results showed that neural flexibility of whole brain, motor, and high-order brain functional networks/regions increased significantly with age, while visual regions exhibited a temporally stable pattern, suggesting spatially and temporally nonuniform developmental features of neural flexibility. Additionally, the neural flexibility of the primary visual network at 3 mo of age was significantly and negatively associated with cognitive ability evaluated at 5/6 y of age. The “flexible club,” comprising brain regions with neural flexibility significantly higher than whole-brain neural flexibility, were consistent with brain regions known to govern cognitive flexibility in adults and exhibited unique characteristics when compared to the functional hub and diverse club regions. Thus, MR-derived neural flexibility has the potential to reveal the underlying neural substrates for developing a cognitively flexible brain during early infancy.

Stabilization of Brain Network Dynamics during Childhood and Adolescence is Associated with Gene Expressions

“…The spatial pattern observed from our child rsfMRI dataset showed a regional distribution of modular variability similar to that of the adult brain described in previous studies. A similar spatial pattern was also observed in a previous study on functional module switching in infants (Yin et al, 2020). Combining our observations with prior findings in studies on the adult (Chen et al, 2016;Liu et al, 2020;Pedersen et al, 2018) and infant brain (Yin et al, 2020), we speculate that the spatially heterogeneous pattern is a common and underlying property that reflects the regional diversity in brain module dynamics.…”

“…Nevertheless, the availability of cerebral cortex gene expression data for children and adolescents could be beneficial for facilitating future exploration of the molecular mechanisms underlying developmental network dynamics. Secondly, previous studies in adults have suggested that brain network dynamics show a relationship with cognitive flexibility (Chen et al, 2016;Yin et al, 2020) and individual task performance (Pedersen et al, 2018). How then is the progressive maturation of brain network dynamics during childhood and adolescence associated with the development of individual cognition and behavior?…”

On the importance of being flexible: dynamic brain networks and their potential functional significances

“…Along these lines, a recent study found that excessive flexibility in the visual areas of infants negatively correlated with the rate at which subsequent developmental milestones were surpassed (Yin et al, 2020). Such a pattern might be expected if efficient perception is reflected by more stable intra-module dynamics.…”

Cognitive and behavioural flexibility: neural mechanisms and clinical considerations

“…The emerging links between brain dynamics and flexible behaviours in neurotypical adults 49 have set the stage for understanding how these processes are affected in development and ageing. Neural flexibility, or the frequency with which brain regions change allegiance between functional modules, has recently been shown to increase with age during the first 2 years of life 50 . At the other end of the lifespan, older adults performing well on a cognitive test battery were found to exhibit brain states characterized by global coherence, whereas those performing poorly exhibited greater frequency of switching between dynamic brain states 51 .…”