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Scholarly Works (158 results)

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UC Davis Previously Published Works (2023)
The neuropeptide hormone oxytocin is involved in many processes in our bodies, linking our social lives to our internal states. I started out my career studying primate families, an interest that expanded into the role of oxytocin in family-oriented behaviors such as pair bonding and parenting in prairie voles, humans, and other primates. Starting as a post-doc with Dr. C. Sue Carter, I also became interested in the role of oxytocin during development and the way that we manipulate oxytocin clinically. During that post-doc and then as a faculty member at the University of California, Davis, I have worked on a number of these questions.
    Cover page: Oxytocin: A developmental journey.
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    UC Davis Previously Published Works (2011)
    The recent study by Anacker, Loftis, and Ryabinin used a novel animal model, the prairie vole, to investigate social effects on drinking. Their finding that same-sex peers modulate their drinking to match each other has intriguing implications for the fields of alcohol research as well as research on social relationships.
      Creative Commons 'BY-NC-ND' version 4.0 license
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      UC Davis Previously Published Works (2020)
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        UC Davis Previously Published Works (2019)
        Rationale: Anandamide is an endocannabinoid that contributes to certain aspects of social behavior, like play and reward, by binding to cannabinoid receptor type 1 (CB1). Most interesting is the recent discovery that anandamide may be mobilized by oxytocin receptor activation under certain contexts, particularly in the nucleus accumbens. Objectives: Given the established role of oxytocin and the nucleus accumbens in the neurobiology of pair-bonding, we investigated whether systemic administration of brain-permeable modulators of the endocannabinoid system could alter preferential partner contact in both male and female prairie voles. Methods: Specifically, we tested whether intraperitoneal administration of the neutral CB1 antagonist AM4113 (4.0–16.0 mg/kg) or the anandamide hydrolysis inhibitor URB597 (5.0–20.0 mg/kg) could prevent or facilitate partner preference formation, respectively. To further investigate the specificity of effects on partner preference, we repeated our URB597 dosing regimen on an additional group of females and tested their anxiety-related behavior in both an elevated-plus maze and a light/dark test. Results: AM4113 administration had no effect on partner preference. But while URB597 also had no effect on partner preference, low-dose females did increase absolute preferential contact with either the partner or the stranger; individual females spent significant contact time with either the partner or the stranger. None of our outcome measures in either anxiety test showed significant effects of treatment. Conclusions: Our results reveal that experimentally increasing anandamide levels in female prairie voles can increase social contact with both a familiar and novel male via unknown mechanisms that are likely separate from anxiety reduction.
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          UC Davis Previously Published Works (2010)
            Cover page: Family Life on the PrairieCreative Commons 'BY-NC-ND' version 4.0 license
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            UC Davis Previously Published Works (2017)
            The study of parenting in animals has allowed us to come to a better understanding of the neural and physiological mechanisms that underlie mammalian parental behavior. The long-term effects of parenting (and parental abuse or neglect) on offspring, and the neurobiological changes that underlie those changes, have also been best studied in animal models. Our greater experimental control and ability to directly manipulate neural and hormonal systems, as well as the environment of the subjects, will ensure that animal models remain important in the study of parenting; while in the future, the great variety of parental caregiving systems displayed by animals should be more thoroughly explored. Most importantly, cross-talk between animal and human subjects research should be promoted.
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              UC Davis Previously Published Works (2017)
              The study of parenting in animals has allowed us to come to a better understanding of the neural and physiological mechanisms that underlie mammalian parental behavior. The long-term effects of parenting (and parental abuse or neglect) on offspring, and the neurobiological changes that underlie those changes, have also been best studied in animal models. Our greater experimental control and ability to directly manipulate neural and hormonal systems, as well as the environment of the subjects, will ensure that animal models remain important in the study of parenting; while in the future, the great variety of parental caregiving systems displayed by animals should be more thoroughly explored. Most importantly, cross-talk between animal and human subjects research should be promoted.
                Cover page: Parenting in animals
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                UC Davis Previously Published Works (2016)
                This article is part of a Special Issue "Parental Care". Paternal care, though rare among mammals, is routinely displayed by several species of rodents. Here we review the neuroanatomical and hormonal bases of paternal behavior, as well as the behavioral and neuroendocrine consequences of paternal behavior for offspring. Fathering behavior is subserved by many of the same neural substrates which are also involved in maternal behavior (for example, the medial preoptic area of the hypothalamus). While gonadal hormones such as testosterone, estrogen, and progesterone, as well as hypothalamic neuropeptides such as oxytocin and vasopressin, and the pituitary hormone prolactin, are implicated in the activation of paternal behavior, there are significant gaps in our knowledge of their actions, as well as pronounced differences between species. Removal of the father in biparental species has long-lasting effects on behavior, as well as on these same neuroendocrine systems, in offspring. Finally, individual differences in paternal behavior can have similarly long-lasting, if more subtle, effects on offspring behavior. Future studies should examine similar outcome measures in multiple species, including both biparental species and closely related uniparental species. Careful phylogenetic analyses of the neuroendocrine systems presumably important to male parenting, as well as their patterns of gene expression, will also be important in establishing the next generation of hypotheses regarding the regulation of male parenting behavior.
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                  UC Davis Electronic Theses and Dissertations (2023)

                  In humans and other pair-bonding species, mates form relatively long-lasting psychological attachments with each other that help them survive, reproduce, and rear offspring. This dissertation examined the biological, psychological, and evolutionary correlates of pair bonding and parenting (two primary types of attachment relationships) in both humans and titi monkeys.

                  In Chapter 1, I assessed whether romantic first impressions from initial interactions between potential partners (humans) predicted later relational outcomes (e.g., later romantic desire, contact attempts, direct messaging) using a design that could tease apart different possible mechanisms (e.g., mate value, selectivity, compatibility). Consistent with evolutionary models of human pair bonding, I found that, across three speed-dating studies (N = 559), mate value (average r = 0.22) and compatibility (average r = 0.15) were the best predictors of relationship-initiation, which indicates that these factors can have lingering effects on relationship development (even from the moment that two potential partners meet).

                  In Chapter 2, I assessed whether initial compatibility played a similar role in relationship development in titi monkeys (Plecturocebus cupreus) (n = 12), a socially monogamous and biparental nonhuman primate species. To do this, I developed a “monkey speed-dating test” to assess subjects’ initial preferences for different potential mates, and then paired subjects according to compatibility. Consistent with the results of Chapter 1, I found that, on average, the six speed-dating pairs exhibited higher levels of affiliative Tail Twining (β = 0.31) compared to a group of 13 age-matched comparison pairs. I also found that the degree of initial compatibility within speed-dating pairs predicted higher levels of Combined Affiliation at earlier post-pairing time points (with the association peaking at 2 months post-pairing, β = 0.57), which suggests that initial compatibility acted as a catalyst for pair bonding.

                  In Chapter 3, I investigated the neuroendocrine correlates of the parent-offspring bond in titi monkeys across a set of three studies. In Studies 1-2, I used receptor autoradiography to correlate vasopressin receptor 1a (AVPR1a) binding in the hippocampus (Study 1, n = 10) and the rest of the forebrain (Study 2, n = 23) with parental status, parental experience, parity, infant carrying, and pair affiliation. I found that parents exhibited lower AVPR1a binding than non-parents throughout most brain regions assessed, with especially strong effects in the hippocampus (β = -0.61), superior colliculus (β = -0.88), lateral septum (β = -0.35), and medial preoptic area (β = -0.29). In Study 3 (n = 44), I compared pre- and postpartum urinary androgen levels in parents and non-parents and found that mothers exhibited a sustained androgen decrease across 3-4 months postpartum (relative to 3 months prepartum; β ranged from -0.72 to -0.62 for different comparisons). For males, multiparous fathers exhibited decreased androgen levels at 1-2 weeks postpartum (β = -0.25) and at 3-4 months postpartum (β = -0.40) compared to the prepartum, indicating both immediate and long-term reductions with subsequent paternal experience. Together, these results suggest that decreases in AVPR1a binding and circulating androgens are associated with parental behavior and physiology in titi monkeys.

                  The primary results for each study are presented in each dissertation chapter. For information about secondary analyses that were performed in each chapter, see the Supplementary Information files for each respective chapter.

                  • 3 supplemental ZIPs
                  • Article
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                  UC Davis Previously Published Works (2020)
                  In prairie voles (Microtus ochrogaster), biparental care of offspring is typical, and paternal absence in the pre-weaning development of offspring alters biobehavioral development. We sought to determine whether this altered development is due to the absence of specific paternal qualities or a general reduction in pup-directed care. We compared the biobehavioral development of pups reared under conditions of biparental (BPC), maternal-plus-alloparental (MPA; i.e., mother and older sister), and maternal only (MON) care. Older sisters provided a quantity of care equal to or greater than that of fathers. Growth rate and developmental milestones were unaffected by family composition, with the exception of earlier fur growth in MON conditions. In adulthood, we tested behaviors on an elevated plus maze, spontaneous alloparental care, and partner preference formation. We found no significant differences on the elevated plus maze and only marginal differences in alloparental care. While both female and male MON individuals showed deficits in partner preference formation, MPA females showed typical partner preference formation. However, the alloparental substitution of fathers was not sufficient for the typical development of partner preference formation in males. We conclude that paternal care plays a differentially important role in the social development of female and male prairie vole offspring.
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