OXYTOCINERGIC CORTICAL CIRCUITS FOR MOTHER-INFANT COORDINATION DURING NURSING

Infant nursing is a conserved feature across mammals and requires precise coordination between mother and infant to ensure effective attachment and suckling. In humans, successful breastfeeding—often supported by interventions targeting maternal posture and positioning—is associated with substantial health benefits, yet the neural mechanisms underlying such maternal bodily adjustments remain poorly understood.
While hardwired subcortical circuits mediate core parental behaviors, fine-tuned postural and sensorimotor coordination during nursing is likely supported by experience-dependent plasticity in cortical circuits. Oxytocin has been implicated in maternal plasticity across multiple brain regions, including the cortex, but its role in shaping cortical mechanisms for precise mother–infant coordination during nursing is unknown.
Here, we investigate oxytocinergic modulation of the somatosensory cortex (S1) ventrum representation and its contribution to cortical plasticity and maternal behavior during nursing. Using a local oxytocin receptor (OTR) knock-out (KO) in lactating rats, we find that receptive field plasticity in ventral S1 is impaired. Cell-type–specific analyses reveal that OTR-expressing neurons in this region are predominantly inhibitory, suggesting a circuit mechanism involving oxytocin-dependent lateral inhibition. Consistent with this idea, multi-shank electrophysiological recordings show that OTR-KO animals exhibit less-sharpened cortical response fields compared to controls. At the behavioral level, OTR-KO impairs maternal bodily adjustments, reduces milk-ejection–associated behaviors, and increases within-litter variability in pup weight. Finally, acute optogenetic inhibition of OTR-expressing neurons recapitulates the body-part adjustment deficits observed after OTR-KO.
Together, our results identify oxytocin-dependent plasticity in somatosensory cortical circuits as a potential mechanism supporting precise mother–infant coordination during nursing.