A 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 studies linking reward, emotion regulation, empathy, and mentalization networks to the parental brain. Here, we used MEG in 43 first-time mothers listening to infant and adult cry vocalizations to investigate the link with mother-infant postpartum bonding scores and their level of sleep deprivation (assessed using both actigraphy and sleep logs). When comparing brain responses to infant versus adult cry vocalizations, we found significant differences at around 800-1,000 ms after stimuli onset in the primary auditory cortex, superior temporal gyrus, hippocampal areas, insula, precuneus supramarginal gyrus, postcentral gyrus, and posterior cingulate gyrus. 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 100-300 ms after the stimulus onset. In contrast, we did not find correlations with sleep deprivation scores. The significant decreases in brain processing of an infant's distress signals could potentially be a novel signature of weaker infant bonding in new mothers and should be investigated in vulnerable populations.

Automated summary

Studies using MEG have found that the orbitofrontal cortex is an important hub for the parental instinct in the brain, and it is linked to reward, emotion regulation, empathy, and mentalization networks. In this study, MEG was used to investigate the brain responses of first-time mothers listening to infant and adult cry vocalizations. It was found that mothers with weaker bonding scores showed decreased brain responses to infant cries in various brain regions. However, no correlation was found with sleep deprivation scores.