Summary: Connections between oxytocin neurons in the hypothalamus and dopamine neurons in the reward system drive parenting behaviors in both male and female voles.
Like female voles, connections between oxytocin neurons in the hypothalamus and dopamine neurons in reward areas drive parental behaviors in male voles, according to new research published in Journal of Neuroscience.
Motherhood receives most of the attention in the research world, yet in 5% of mammals — including humans — fathers provide care, too.
The “love hormone” oxytocin plays a role in paternal care, but the exact neural pathways underlying the behavior were not known.
He et al. measured the neural activity of vole fathers while they interacted with their offspring.
Oxytocin neurons connecting the hypothalamus to a reward area fired when the fathers cared for their offspring. Stimulating the oxytocin neurons increased paternal behaviors, while inhibiting them reduced paternal behaviors.
Inhibiting the pathway led to decreased dopamine release in the reward area when the fathers cared for their pups. These pathways are the same ones involved in promoting maternal behavior in female animals.
Understanding the pathways driving paternal care could lead to interventions for paternal postpartum depression or paternal abuse.
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Source: SfN Contact: Calli McMurray – SfN Image: The image is credited to He et al
Paraventricular nucleus oxytocin sub-systems promote active paternal behaviors in mandarin voles
Paternal care plays a critical role in the development of brain and behaviors in offspring in monogamous species. However, the neurobiological mechanisms, especially the neuronal circuity, underlying paternal care is largely unknown.
Using socially monogamous male mandarin voles (Microtus mandarinus) with high levels of paternal care, we found that paraventricular nucleus of the hypothalamus (PVN) to ventral tegmental area (VTA) or nucleus accumbens (NAc) oxytocin (OT) neurons are activated during paternal care. Chemogenetic activation/inhibition of the PVN OT projection to VTA promoted/decreased paternal care, respectively.
Chemogenetic inhibition of the PVN to VTA OT pathway reduced dopamine (DA) release in the NAc of male mandarin voles during licking and grooming of pups as revealed by in vivo fiber photometry. Optogenetic activation/inhibition of the VTA to NAc DA pathway possibly enhanced/suppressed paternal behaviors, respectively. Furthermore, chemogenetic activation/inhibition of PVN to NAc OT circuit enhanced/inhibited paternal care.
This finding is a first step toward delineating the neuronal circuity underlying paternal care and may have implications for treating abnormalities in paternal care associated with paternal postpartum depression or paternal abuse.
Paternal behavior is essential for offspring survival and development in some mammalian species. However, the circuit mechanisms underlying the paternal brain are poorly understood.
We show that manipulation of PVN to VTA OT projections as well as VTA to NAc DA projections promote paternal behaviors. Inhibition the PVN to VTA OT pathway reduces DA release in the NAc during pup licking and grooming. PVN to NAc OT circuit is also essential for paternal behaviors.
Our findings identify two new neural circuits that modulate paternal behaviors.