Patterns of Infant Amygdala Connectivity Mediate the Impact of High Caregiver Affect on Reducing Infant Smiling: Discovery and Replication

Abstract Background Behavioral research indicates that caregiver mood disorders and emotional instability in the early months following childbirth are associated with lower infant positive (PE) and higher negative emotionality (NE), but the neural mechanisms remain understudied. Methods Using resting state functional connectivity (rs-FC) as a measure of the functional architecture of the early infant brain, we aimed to determine the extent to which connectivity between the amygdala, a key region supporting emotional learning and perception, and large-scale neural networks mediated the association between caregiver mood and anxiety and early infant NE and PE. Two samples of infants (first sample: n=58; second sample: n=31) aged 3-months underwent an MRI scan during natural sleep. Results During infancy, greater rs-FC between the amygdala and the salience network, and, to a lesser extent, lower amygdala-and executive control network rs-FC, mediated the effect of greater caregiver postpartum depression and trait anxiety on reducing infant smiling (p Conclusions We provide evidence of early objective neural markers that can help identify those infants who are more likely to be at risk from, versus those who might be protected against, the deleterious effects of caregiver depression and anxiety and reduced PE.