Fusiform face area development correlates with development in higher-order social brain regions

3.The fusiform face area (FFA) preferentially responds to faces within the first months of life. One hypothesis is that higher-order social responses in middle medial prefrontal cortex (MMPFC) or face responses in superior temporal sulcus (STS) drive the development of face-selective responses in FFA, with right-hemisphere dominance in FFA eventually arising from lateralised connections to these regions. Another hypothesis proposes an innate face template in the amygdala guides attention to face-like shapes. This study opportunistically examined the development of the FFA, MMPFC, STS, and amygdala in childhood using an open cross-sectional movie-viewing fMRI dataset with 3-12-year-olds (N=117, M=6.77 years) and adults (N=33, M=24.77 years). We tested for correlations between FFA development and development in MMPFC, STS, and amygdala on the premise that associations between these regions may be observable even in children, and such associations could constrain hypotheses and analytic approaches in future studies with infants. First, we measured functional maturity-how similar each childs response to the movie was to an adult average response timecourse. In all regions, older childrens responses were more adult-like. Next, we tested whether FFA maturity correlated with functional connectivity with, or functional maturity of, MMPFC, STS, or amygdala. Children with more mature right FFA responses showed stronger right FFA-right MMPFC connectivity. Children with more mature FFA responses also had more mature STS responses, bilaterally. This study provides preliminary evidence that FFA co-develops with higher-order social brain regions and specific metrics to take forward in future research with infants. HighlightsO_LIWhat drives face selective responses in FFA is the subject of recent debate. C_LIO_LI117 children aged 3 to 12 years watched a short movie while undergoing fMRI. C_LIO_LIRight FFA development correlated with functional connectivity to right MMPFC C_LIO_LIFFA development correlated with STS development, bilaterally. C_LIO_LIFFA codevelops with higher-order social brain regions (controlling for age). C_LI