Reorganization of the maternal brain upon childbirth triggers the species-typical maternal social behavior. These brief social moments carry profound effects on the infant's brain and likely have a distinct signature in the maternal brain. Utilizing a double-blind, within-subject oxytocin/placebo administration crossover design, mothers' brain was imaged twice using fMRI while observing three naturalistic maternal-infant contexts in the home ecology; ‘unavailable’, ‘unresponsive’, and ‘social’, when mothers engaged in synchronous peek-a-boo play. The social condition elicited greater neural response across the human caregiving network, including amygdala, VTA, hippocampus, insula, ACC, and temporal cortex. Oxytocin impacted neural response primarily to the social condition and attenuated differences between social and non-social stimuli. Greater temporal consistency emerged in the ‘social’ condition across the two imaging sessions, particularly in insula, amygdala, and TP. Findings describe how mother's brain varies by caregiving experiences and gives salience to moments of social synchrony that support infant development and brain maturation.
