Functional connectivity for the language network in the developing brain: 30 weeks of gestation to 30 months of age

Abstract

Although the neural scaffolding for language is putatively present before birth, the maturation of functional connections among the key nodes of the language network, Broca’s and Wernicke’s areas, is less known. We leveraged longitudinal and cross-sectional data from three sites collected through six studies to track the development of functional circuits between Broca’s and Wernicke’s areas from 30 weeks of gestation through 30 months of age in 127 unique participants. Using resting-state fMRI data, functional connectivity was calculated as the correlation between fMRI time courses from pairs of regions, defined as Broca’s and Wernicke’s in both hemispheres. The primary analysis evaluated 23 individuals longitudinally imaged from 30 weeks postmenstrual age (fetal) through the first postnatal month (neonatal). A secondary analysis in 127 individuals extended these curves into older infants and toddlers. These data demonstrated significant growth of interhemispheric connections including left Broca’s and its homolog and left Wernicke’s and its homolog from 30 weeks of gestation through the first postnatal month. In contrast, intrahemispheric connections did not show significant increases across this period. These data represent an important baseline for language systems in the developing brain against which to compare those neurobehavioral disorders with the potential fetal onset of disease.

Brain age prediction and deviations from normative trajectories in the neonatal connectome

“…Broca's region) are reportedly primed to learn language from birth 35,36 . The functional connectivity associated with these regions may take years to form 8,[37][38][39] .…”

“…Early functional connections are observed in the fetal period 6 , and lower-order networks (e.g., motor-sensory) are present at birth 5 . However, many functional networks (e.g., the default mode network) only resemble older children after the first year of life 7,8 . Nevertheless, emerging research suggests that most functional networks are detectable in the neonatal period 9 with larger samples and higher-quality data.…”

Specialization of the brain for language in children with Fragile X Syndrome: A functional Near Infrared Spectroscopy study

“…In humans, cortical specialization for language is present at birth and develops extensively over the rst few years of life and into childhood [22][23][24]. Two consistent features of cortical specialization in infants with typical development are differential activation to speech and nonspeech sounds [25,26] and lateralization of response to speech in the left hemisphere [27,28].…”