Motherhood and DREADD manipulation of the nucleus accumbens weaken established pair bonds in female prairie voles

Re‐wiring of the bonded brain: Gene expression among pair bonded female prairie voles changes as they transition to motherhood

“… 2 , 71 In particular, the onset of motherhood has been associated with significant neural and behavioral changes in response to shifting priorities, 1 , 6 potentially creating a trade‐off between the care of current offspring and future reproductive success. 72 The onset of motherhood and associated maternal behaviors of prairie voles appears to result in decreased pair bond strength, whereas vasectomized reproductively unsuccessful pairs (like those in our control groups here) do not show this decrease in bond strength ( 16 ; but see Curtis 73 ). In this study, we provide evidence that the social contextual shift associated with the life‐history transition to motherhood also results in a distinct pattern of gene expression for at least five genes ( oxtr , d1r , d2r , oprm1a , and oprk1a ) in the brain of pregnant and mothering pair bonded female prairie voles.…”

“…Such priming could be accomplished by altering modulation of a female's response to social cues, 100 potentially increasing the salience of novel pup stimuli and decreasing the valence of the familiar mating partner's social cues. 16 …”

“…Indeed, studies on pair bonding species have indicated that energetic trade‐offs associated with maternal care may come at the cost of partner‐directed behavior. 15 , 16 , 17 , 18 Moreover, a decrease in time spent with a partner following childbirth leads to a decrease in marital satisfaction among married couples. 15 , 19 , 20 Similarly, feelings of separation and exclusion from the mother‐infant bond contribute to high rates of postpartum depression in new fathers, 21 , 22 , 23 suggesting a change in the pair bond is experienced by both partners after offspring birth.…”

“…Similarly, female prairie voles ( Microtus ochrogaster ) are a socially monogamous and biparental rodent that exhibit lower rates of partner‐directed grooming following the birth of offspring 24 and show a significant decrease in pair bond strength when tested shortly after parturition. 16 Considering the neural mechanisms governing pair bonding have been relatively well outlined in the prairie vole, 25 , 26 we are well positioned to use this species to begin to uncover how the social brain regulates the formation of novel social relationships and how this may impact the maintenance of established social bonds.…”

“…Moreover, these brain areas represent points of confluence between each of the aforementioned sub‐networks, and they are each modulated by oxytocinergic, dopaminergic, and opioidergic signaling. 16 , 31 , 40 , 45 , 46 Specifically, we predicted that gene expression within these brain regions would show consistent patterns, reflecting coordination of the suite of signaling molecules that regulate the behaviors associated with the life‐history stages we investigated. We also predicted that gene expression would reflect functional differences in modulating brain function associated with the transition from being bonded with a mating partner to establishing new bonds with offspring.…”