Critical periods of brain growth and cognitive function in children

Area of Science:

• Neuroscience
• Developmental Psychology
• Pediatrics

Background:

• Existing research suggests a link between physical growth (birth weight, height) and intelligence quotient (IQ).
• The relative importance of brain growth during different developmental stages (fetal vs. postnatal) on cognitive function remains unclear.

Purpose of the Study:

• To investigate the relationship between brain growth across different pre- and postnatal periods and cognitive function in children.
• To determine the relative importance of fetal versus postnatal brain development on intelligence.

Main Methods:

• Assessed cognitive function using the Wechsler Abbreviated Scale of Intelligence in 221 nine-year-old children and their mothers.
• Measured head circumference at 18 weeks gestation, birth, and 9 months of age, and again at 9 years for the children.
• Controlled for various confounding factors including maternal IQ, socioeconomic status, and education.

Main Results:

• A significant positive association was found between head circumference at 9 months and 9 years of age and full-scale IQ at age 9.
• Each standard deviation increase in head circumference at 9 months correlated with a 1.98-point rise in IQ, and at 9 years with a 2.87-point rise.
• No significant relationship was observed between IQ and head circumference measurements taken at 18 weeks gestation or at birth.

Conclusions:

• Brain growth during infancy and early childhood appears more critical for cognitive function than growth during fetal development.
• Postnatal head growth is associated with higher socioeconomic status and maternal education levels.
• These findings highlight the critical window of postnatal brain development for cognitive outcomes.