Researchers have scanned the brains of more than 500 babies and young children in order to paint a detailed picture of the brain’s development during the first six years of life. By observing how functional connectivity within and between different brain networks changes at different timepoints, the study authors were able to map out a series of cognitive milestones that are characteristic of a “normal” developmental pattern.
Furthermore, the researchers noted that deviations from this typical growth chart correlate with differences in cognitive abilities among young children. Based on this observation, they say that brain scans like those used in the study “may provide an effective tool to monitor normative functional development”.
To reach these conclusions, the study authors analyzed a total of 1,091 functional MRI scans of neurotypical children from birth to six years of age. This enabled them to establish “normative growth curves for eight functional networks,” including the primary, default, control, attention, and visual networks.
For instance, within the visual network, the researchers found that functional connectivity (FC) generally increases during the first five months of life, coinciding with the emergence of “higher-order visual functions, such as facial/object recognition and visual attention.” After this point, however, FC decreases, possibly reflecting a fine-tuning and specialization of different subsystems within the visual network.
“The importance of visual functions in cognitive development is well established,” write the authors. “For example, measures of infant visual performance, such as attention and fixation, have been shown to predict neurocognitive development,” they continue, thus highlighting the importance of normal growth within the visual network.
Another key finding entailed “the rapid integration of the limbic and control networks” during the first two years of life, before connectivity between these two hubs stabilizes around 26 months of age. According to the researchers, this “reflects the formation of emotion regulation” and explains why babies rely more on maternal affection than self-soothing while toddlers develop “more independent, attention-seeking and escape behaviour during periods of maternal unavailability.”
Wondering how the normative growth charts identified in this study might influence cognitive development, the researchers point out that “abnormalities associated with the task-positive networks and the default network… have been widely observed in neurodevelopmental disorders, such as attention-deficit/hyperactivity disorder and autism.” They therefore conducted a series of cognitive assessments on a subset of the children who took part in the study, finding that fluctuations in FC development could be used to predict performance levels.
“Specifically, connections involving the primary, default, control and attention networks were key predictors,” they write. Overall, they say, these findings delineate the ways in which “[brain] network functions in early infancy are crucial for the development of cognition.”
The study has been published in the journal Nature Human Behaviour.
Source Link: Cognitive Milestones From Birth To Age 6 Revealed In New Brain Imaging Study
