A potential marker for problematic mother-infant bonding revealed by magnetoencephalography study of first-time mothers listening to infant cries

Studies using magnetoencephalography (MEG) have identified the orbitofrontal cortex (OFC) to be an important early hub for a parental instinct in the brain. This complements the finding from functional magnetic resonance imaging (fMRI) studies linking reward, emotion regulation, empathy and mentalisation networks to the parental brain. Here, we used MEG in 43 first-time mothers listening to infant and adult cry vocalisations to investigate the link with mother-infant postpartum bonding scores and their level of sleep deprivation (assessed using both actigraphy and sleep logs). We found significant differences 800-1000ms after onset of infant compared to adult cries in source-reconstructed brain activity in areas previously linked to the parental brain. Importantly, mothers with weaker bonding scores showed decreased brain responses to infant cries in the auditory cortex, middle and superior temporal gyrus, OFC, hippocampal areas, supramarginal gyrus and inferior frontal gyrus at around 100-200ms after stimulus onset. In contrast, we did not find correlations with sleep deprivation scores. The significant changes in brain processing of an infants distress signals could be a novel marker of weaker infant bonding in new mothers and should be investigated in vulnerable populations.