Impact of prenatal exposure to airborne particulate matter on local functional connections in the cerebral cortex of neonates.

Neuroimaging studies suggest that air pollution exposure interferes with brain functional development, potentially affecting long-term cognitive abilities. Early life may represent a critical window of vulnerability, yet most research has assessed exposure effects later in childhood, when postnatal influences accumulate. This study examined the early impact of prenatal exposure to airborne particulate matter (PM2.5) on the functional structure of local connections in the cerebral cortex of neonates. This population-based study was conducted in Barcelona between 2018 and 2021. PM₂.₅ exposure was estimated using land-use regression models incorporating time-weighted maternal mobility data across distinct environments. Resting-state functional MRI scans were obtained from 61 neonates at 29 days postnatally. Brain functional connectivity was assessed using local Iso-Distant Average Correlation (IDAC) measures across different spatial distances. Voxel-wise regression analyses were performed to examine associations between PM2.5 exposure and IDAC measures. Higher maternal PM2.5 exposure during gestation was associated with stronger local functional connectivity in the neonatal cortex, particularly in brain regions involved in sensorimotor function. In the premotor and supplementary motor cortices, these effects varied by spatial scale, showing stronger associations at longer local distances. The findings suggest that prenatal exposure to air pollution interferes with early brain functional organization. Notably, the observed connectivity changes could reflect both a delay in the segregation of primary sensorimotor areas and the acceleration of functional maturation in higher levels of the sensorimotor system. Longitudinal studies are needed to track how these exposure-related alterations evolve over time and their potential impact on developmental outcomes.