Question

A new model of transgenic vole was created in which all females are spontaneously maternal. Which experimental manipulation would you expect to cause this result?

A) over expression of oxytocin in the ventral pallidum

B) over expression of D2 receptors in the caudate putamen

C) over expression of vasopressin receptors in the nucleus accumbens

D) over expression of oxytocin receptors in the nucleus accumbens

Answer 1

A new model of transgenic vole was created in which all females are spontaneously maternal. The experimental manipulation i would expect to cause this result is: Over expression of vasopressin receptors in the nucleus accumbens. (Option C)
Understanding the neurobiological substrates regulating normal social behaviours may provide valuable insights in human behaviour, including developmental disorders such as autism that are characterized by pervasive deficits in social behaviour. Here, we review the literature which suggests that the neuropeptides oxytocin and vasopressin play critical roles in modulating social behaviours, with focusing on their role in the regulation of social bonding in monogamous rodents. Oxytocin and vasopressin contribute to a wide variety of social behaviours, which includes social recognition, communication, parental care, territorial aggression and social bonding. The effects of these two neuropeptides are species-specific and depend on species-specific receptor distributions in the brain. Comparative studies in voles with divergent social structures have revealed some of the neural and genetic mechanisms of social-bonding behaviour. Prairie voles are socially monogamous; males and females form long-term pair bonds, establish a nest site and rear their offspring together. In contrast, montane and meadow voles do not form a bond with a mate and only the females take part in rearing the young. Species differences in the density of receptors for oxytocin and vasopressin in ventral forebrain reward circuitry differentially reinforce social-bonding behaviour in the two species. High levels of oxytocin receptor in the nucleus accumbens and high levels of vasopressin 1a receptor in the ventral pallidum contribute to monogamous social structure in the prairie vole. While little is known about the genetic factors contributing to species-differences in OTR distribution, the species-specific distribution pattern of the V1aR is determined in part by a species-specific repetitive element, or ‘microsatellite’, in the 5′ regulatory region of the gene encoding V1aR. This microsatellite is highly expanded in the prairie vole compared to a very short version in the promiscuous montane and meadow voles. These species differences in microsatellite sequence are sufficient to change gene expression in cell culture. Within the prairie vole species, intraspecific variation in the microsatellite also modulates gene expression in vitro as well as receptor distribution patterns in vivo and influences the probability of social approach and bonding behaviour. Similar genetic variation in the human AVPR1A may contribute to variations in human social behaviour, including extremes outside the normal range of behaviour and those found in autism spectrum disorders. In sum, comparative studies in pair-bonding rodents have revealed neural and genetic mechanisms contributing to social-bonding behaviour. These studies have generated testable hypotheses regarding the motivational systems and underlying molecular neurobiology involved in social engagement and social bond formation that may have important implications for the core social deficits characterising autism spectrum disorders.
PS: If the answer helps you please give a positive feedback rating. It is really very important to us