IQ, fetal testosterone and individual variability in children's functional lateralization

Area of Science:

• Neuroscience
• Developmental Psychology
• Cognitive Neuroscience

Background:

• Event-related potential (ERP) studies show distinct N170 lateralization for faces versus words in adults.
• The developmental trajectory of this differential lateralization in children remains unclear.
• Factors like fetal testosterone, reading skill, and IQ may influence brain lateralization.

Purpose of the Study:

• Investigate the development of differential N170 lateralization for faces and words in school-age boys.
• Examine the role of fetal testosterone (FT) in prenatal biasing of lateralization.
• Assess the influence of reading skill and Verbal IQ on word lateralization.

Main Methods:

• Recorded event-related potentials (ERPs) in 26 school-age boys.
• Measured N170 component lateralization for face and word stimuli.
• Correlated lateralization scores with fetal testosterone levels, reading skill, and IQ measures.

Main Results:

• The adult pattern of differential N170 lateralization for faces and words was absent in school-age boys.
• Fetal testosterone levels did not significantly predict individual differences in lateralization.
• Verbal IQ correlated with left lateralization for words, but not specifically for language.
• Strong correlations were found between left lateralization for words and faces, and both correlated with IQ.

Conclusions:

• N170 lateralization for faces and words likely develops later in childhood, possibly with increased experience or late maturation.
• Prenatal testosterone levels do not appear to be a major factor in this developmental process.
• While IQ correlates with lateralization, the relationship is complex and not solely tied to language abilities.