Early Infant Prefrontal Cortical Microstructure Predicts Present and Future Emotionality

BACKGROUND High levels of infant negative emotionality (NE) and low positive emotionality (PE) predict future emotional and behavioral problems. The prefrontal cortex (PFC) supports emotional regulation, with each PFC subregion specializing in specific emotional processes. Neurite Orientation Dispersion and Density Imaging (NODDI) estimates microstructural integrity and myelination via the neurite density index (NDI) and dispersion via the orientation dispersion index (ODI), with potential to more accurately evaluate microstructural alterations in the developing brain. Yet, no study has used these indices to examine associations between PFC microstructure and concurrent or developing infant emotionality. METHODS We modeled PFC subregional NDI and ODI at 3 months with caregiver-reported infant NE and PE at 3 months (n=61) and at 9 months (n=50), using multivariable and subsequent bivariate regression models. RESULTS The most robust statistically-significant findings were positive associations among 3-month rACC ODI and cACC NDI and concurrent NE, and 3-month lOFC ODI and prospective NE; and a negative association between 3-month dlPFC ODI and concurrent PE. Multivariate models also revealed that other PFC subregional microstructure measures, and infant and caregiver sociodemographic and clinical factors, predicted infant 3- and 9-month NE and PE. CONCLUSIONS Greater NDI and ODI, reflecting greater microstructural complexity, in PFC regions supporting salience perception (rACC), decision-making (lOFC), action selection (cACC), and attentional processes (dlPFC) might result in greater integration of these subregions with other neural networks, greater attention to salient negative external cues, thus higher NE and/or lower PE. These findings provide potential infant cortical markers of future psychopathology risk.