A recent study published in the Journal of Developmental Cognitive Neuroscience looked at white matter in infancy and its association with language outcomes in kindergarten.
“Our study conducted a five-year longitudinal investigation of children from infancy to examine how early brain structure (here focusing on white matter axonal connections between different brain areas) relates to children’s later language outcomes at the start of formal schooling (i.e., kindergarten),” study author Dr. Jennifer Zuk told us. “While well-established research has demonstrated the importance of environmental experience in shaping the trajectory of language acquisition, the neural basis for language has also been shown to develop even before birth (prenatally). Therefore, we were hoping to find out whether the structural foundation of the brain established in infancy is prospectively associated with children’s long-term language outcomes.”
Recent work in the field of developmental cognitive neuroscience proposes that the first two years of life signify the most rapid period of brain development and sets a foundation for long-term development, but there had yet to be direct evidence with respect to brain structure due to a lack of longitudinal designs that employ structural neuroimaging from infancy. On the other hand, recent research has also shown that the quantity and quality of language environmental exposure in early childhood has been linked with language abilities, and even brain structure among preschoolers. The current study’s researchers were curious to establish the extent to which structural organization of the brain from as early as infancy may be related to later language outcomes.
“The acquisition of language skills is at the center of our ability to engage and connect with others and participate in society,” Dr. Zuk told us. “Therefore, language acquisition is of great importance to a child’s development. This study is one component of a larger mission of this research team focused on early identification of children susceptible to develop language-based learning disorders, and promoting positive outcomes for all children.”
Researchers initially recruited families with infants (ages 4-18 months), who agreed to complete structural neuroimaging in infancy while the infants were sleeping. They employed Magnetic Resonance Imaging (MRI) to measure brain structure with infants using a natural sleep approach, meaning, they worked closely with parents to re-create children’s napping routines in their MRI environment and acquired neuroimaging while the infants were naturally sleeping. Over time, they later followed up with these infants’ families five years later and used a variety of language assessments to track each child’s development. They then conducted longitudinal brain-behavior analyses to examine associations between brain structure in infancy and later language outcomes.
“Our neuroimaging analyses focused on one crucial aspect of brain structure: white matter organization in the brain, which refers to structural pathways that connect brain regions and allow for efficient signal transmission,” Dr. Nadine Gaab told us. “We focused on white matter pathways known to be important for language, particularly the arcuate fasciculus. The importance of the left arcuate fasciculus for language has been demonstrated among school-age children and adults.”
Yet, the findings revealed that structural organization of the arcuate fasciculus in infancy is prospectively associated with later language outcomes (specifically in the areas of phonological awareness and vocabulary knowledge). These relationships were significant even when controlling for additional contributing factors that may impact language development, including aspects of the child’s home environment (e.g., how often parents read to their children).
“We were pretty amazed by these results!” Dr. Gaab told us. “We did not know how early in child development we would be able to detect relationships between early brain structure and later language ability, since we know environmental experience over time plays a major role in shaping language development. Based on our findings, our working hypothesis is that the structural foundation for the brain established in infancy is built upon and refined by experience throughout development.”
Dr. Zuk and Dr. Gaab believe their findings illuminate the importance of the first two years of life in establishing brain structure that sets a foundation for long-term language development in early childhood. Going forward, they say these findings highlight the importance of the first two years of life in setting children up for long-term achievement. Further research is needed to examine the impact of environmental experience within the first two years of life in shaping these brain structures during this especially rapid period of brain development, to specify the role of the environment in shaping a foundation for long-term development.