Cortical oxytocin modulation underlying touch-related maternal care
Anatomy and Physiology
Experimental and Theoretical Network Neuroscience
Molecular Biology and Physiology of Neurons and Glial Cells
Final Report Abstract
In this study we focused on the role of oxytocin in the somatosensory cortex during maternity. We found that oxytocin is necessary for neuronal plasticity in lactating rats. Specifically, receptive fields were less sharpened following OTR-KO in the somatosensory ventrum / nipple representation of lactating rats. This suggests that tactile perception may be impaired in these animals. We therefore investigated touch-related maternal behavior during nursing and asked whether they would be impaired in KO animals. Besides well-studied behaviors, such as crouching and licking we annotated previously unstudied maternal body limb adaptations. Strikingly, these body limb adaptations were strongly reduced in OTR-KO animals compared to controls. In contrast, crouching was not impaired - which was surprising to us as these are similar body part adaptations involving adaptations of the trunk. We also found less strong - but significant - reduction of licking behavior in OTR-KO animals, which was again unexpected. As the ventral trunk / nipple representation of S1 is unlikely directly involved in licking behavior it may be that the localized knockdown may have brain-wide effects. To investigate the anatomical basis of OT function in S1 we infected the ventrum / nipple representation of OTR-Cre knock-in rats with a combination of Cre-depdendent AAVs expressing reporters in all OTR neurons and only GABAergic OTR interneurons and found that most of OTR cells had an inhibitory phenotype. This suggests that lateral inhibition may be a likely explanation for the receptive field sharpening observed in rat mothers. In order to investigate how OT reaches S1 we implanted a rat mother with a Neuropixels probe and recorded S1 and PVN neural activity simultaneously. We found that a subset of S1 neurons were strongly activated following OT bursts, which may reflect neural activation of S1 by OT. Taken together, we found that OT plays a crucial role in mediating somatosensory cortex plasticity during lactation and modulates maternal behavior in a way that allows precise mother-infant coordination.
