Attentional bias toward fearful faces is associated with maternal postnatal distress and alterations in white matter microstructure in 5-year-old females

The development of face processing system is paramount for social interaction and communication skills. Eye-tracking provides a viable means to investigate face processing even in very young children and can be used to derive indices of affective processing biases that are adaptive in supporting preparedness for emotional encoding. The neural correlates of early-emerging attentional biases have not been explored. In the current study, we gathered diffusion tensor imaging (DTI) and eye-tracking data (attention disengagement from neutral, happy, fearful faces, and control pictures towards distractor stimuli) to investigate the association of white matter (WM) microstructural alterations and attentional biases in 117 (55 female) typically developing 5-year-old children. We estimated fractional anisotropy (FA) and used tract-based spatial statistics (TBSS) before conducting voxel-wise analyses testing associations between attentional biases and brain diffusivity. We found that reduced WM integrity (indexed as decrease in FA) in widespread WM regions, including the splenium of corpus callosum, left anterior limb of internal capsule (ALIC), left posterior limb of internal capsule (PLIC), left posterior thalamic radiation and optic tract, predicted higher attentional bias toward fearful expressions in females (adjusted for potential confounders). Further, maternal postnatal anxiety and depressive symptoms were detected to associate positively with attentional bias toward fearful expression, but only in females. Based on these findings and prior results on association between maternal distress and reduced WM integrity in female offspring, it is possible that alterations in WM microstructure may transmit the long-term effects of maternal mental distress during early life to increased vigilance towards negative emotional expressions. These hypotheses and sexual dimorphism in the observed associations require replication and are potential focus areas for future studies.