Opioid use disorder (OUD) is a global epidemic affecting a high proportion of child-bearing women. The drastic 4-fold increase in OUD among pregnant women from 1999-2014 has promoted opioid maintenance therapies (OMT) such as buprenorphine (BUP) to mitigate effects associated with opioid abuse. BUP is a mixed (partial mu-receptor agonist/kappa-receptor antagonist) semi-synthetic OMT that produces better infant outcomes after gestational treatment as compared to other OMTs (i.e. methadone). However, effects of BUP on pregnant women transitioning to motherhood is not well understood. Endogenous opioids play a significant role in orchestrating neuronal adaptations within the maternal brain network (MBN) for the successful ‘switch’ from a nulliparous brain to a maternal brain to incentivize nurturing maternal behaviors from the dam. It is well known that exogenous opioid exposure to morphine (full mu-agonist) during gestation can alter the endogenous opioid system and disrupt maternal care. However, there is a knowledge gap about the effects of BUP on the endogenous opioid system during the transition to motherhood and thus on maternal care behavior in the context of OUD during pregnancy. The proposed studies aim to address this knowledge gap by implementing a translational rodent model to evaluate the effects of BUP compared to morphine on the maternal brain, behavior and the microbiome well as on the long-term outcome of the offspring. Female rats will be exposed to BUP and/or morphine in clinically relevant paradigms starting before conception and continued throughout early postpartum. Effects of gestational BUP and morphine exposure on neurochemical and activation pattern changes in the maternal brain will be evaluated using state of the art imaging techniques. We will also evaluate the effectiveness of oxytocin as a potential intervention to increase maternal-offspring interaction in opioid- exposed dams and investigate the role of the microbiome in the long-term health outcome of exposed offspring. Our proposal will be able to add to the preliminary human findings on altered functional connectivity in buprenorphine-exposed mothers by using ‘whole (half) brain activity mapping’ which will allow us to simultaneously illuminate activity at cellular resolution in several brain areas of the MBN and compare patterns between opioid-exposed and control dams and investigate associations with changes in maternal behaviors. We expect that perinatal exposure to BUP inhibits the neuronal ‘switch’ from aversive to rewarding perception of pups that is necessary to initiate appropriate maternal behavior thus subsequently influencing offspring survival. The scale of the opioid epidemic requires an urgent response in order to promote treatment of OUD in pregnancy within an already marginalized population. We hope to advance science on the consequences of opioid drug use/therapy during gestation and to apply these outcomes toward clinical knowledge to improve pub...