Jeffrey A. French - US grants

The continued destruction of the coastal and tropical forest in South and Central America threatens the survival of natural animal populations, including the callitrichid primates (tamarins and marmosets). While the golden lion tamarins are considered an endangered species, through a highly successful breeding program at the University of Nebraska under the auspices of the National Zoological Park, these primates are being bred in captivity and a small group of six have recently been reintroduced into forests of Brazil. Their survival as a species, however, depends extensively on understanding how their reproduction is synchronized to lead to a greater likelihood of fertilization. Dr. French will investigate the complex interplay between internal physiological factors and external social and environmental factors in gold lion tamarins. Unlike Old World primates and apes, the callitrichid primates are monogamous and thus, develop a close and long-lasting association, or pair- bond, between a breeding male and female. Dr. French will use noninvasive data collection techniques for both hormone samples and behavioral measurements to compare the degree to which social factors influence hormonal regulation of reproduction. His findings will be compared with the results obtained in similarly conducted studies in which Old World non-monogamous primate species have been used. This work will contribute to our understanding of the role of hormonal and social influences on reproductive behavior in golden lion tamarins as well as other New World primates of which many are considered threatened or endangered species. Furthermore, the results will significantly enhance the captive breeding programs of endangered species and thus, contribute to the preservation of these small South American primates.

The purpose of the proposed project is to enhance undergraduate instruction in research methods in psychology. The project will facilitate the demonstration of a wide range of psychological phenomena, as well as the design, execution, and analysis of original research by undergraduates. Its impact will be on five upper-division advanced laboratory courses (Learning, Cognitive Psychology, Sensation and Perception, Physiological Psychology, and Animal Behavior), an introductory lab course, and a course in research methods.The core of the project is a bank of 13 microcomputers to serve as student stations for data collection and analysis. One of the computers is to be used for program development, to assist students in designing original research. The software selected will allow students to gain first-hand experience with general principles of research design, and also with the specific techniques associated with particular areas within experimental psychology. This will greatly increase the breadth of research experiences to which students can be exposed, and increase the variety and sophistication of student-initiated research projects (required of all majors) by facilitating instruction in all aspects of the research enterprise.

The relationship between hormones and behavior is no longer viewed as a simple unidirectional effect of hormones on behavior. Rather, the view emerging from studies on animals observed in complex physical and social situations is that there is a sophisticated interplay between social contexts and hormonal status in the production of behavioral interactions. The present studies will further illuminate these relationships in callitrichid primates (marmosets and tamarins). Dr. French has previously shown that social relationships within mated pairs are extremely important in regulating the influence of hormones on behavior. The current studies will evaluate the effects of other social factors in modulating hormones effects on behavior. Specifically, Dr. French will assess whether or not responses of tamarins to unfamiliar intruders differ as a function of the intruding or resident female's reproductive status, will assess whether or not reproductively suppressed subordinate females are capable of expressing patterns of reproductive behavior when removed from the social context that produces suppression, and will evaluate the influence of visual access to unfamiliar pairs on patterns of reproductive behavior across the ovarian cycle. These studies are important in a number of ways. First, the work is relevant to propagation of endangered species. All marmosets and tamarins are considered threatened or endangered, and for some species (e.g., lion tamarins) there are more individuals in captivity than in the wild. It is highly likely that information critical for the enhancement of the propagation of these species in captivity will be the direct result of these studies. Hence, this research may have a profound impact on the maintenance of the biodiversity of tropical animals. Second,these studies will show how complex social settings can influence (reduce or magnify) the effects of internal physiological functions on behavior. These findings as a whole will contribute to a more complex and realistic view of hormones and behavior. Finally, these studies will evaluate hormone-behavior relationships in species of primates that have a social system with many common features of human societies (e.g., high degree of cooperative behavior, joint rearing of offspring, residence of older offspring in family or social groups).

9723842 French Among mammals, infant care is commonly limited to maternal care. However, in a small proportion of species, fathers and other group members contribute to the care and provisioning of dependent infants (paternal and alloparental care, respectively). Although we know much about the patterning of this care, little attention has been directed toward the underlying mechanisms that regulate the delivery of parental care by individuals other than the mother. The studies proposed will examine the physiological and experiential determinants of parental care in the black tufted-ear marmoset (Callithrix kuhli). In the marmoset, maternal effort is limited essentially to nursing, and adult males and older offspring provide the majority of care to dependent infants. Initial observations indicate that older sons and fathers living in family groups undergo breast elaboration in the presence of infants, suggesting an endocrine involvement in infant care by males. Through the use of unobtrusive behavioral observations and noninvasive urine sample collection, French will test the degree to which responsiveness to infants and levels of parental behavior are affected by gonadal steroids (estrogen, progesterone, and testosterone) and pituitary peptides (prolactin). The generality or specificity of the physiological responses to infants will be tested by comparing the endocrine responses of both marmosets and squirrel monkeys (a non-paternal species) to infant-associated stimuli. Further, the strength of the social attachment between male and female partners, assumed to be critical for the evolution of male parental care, will be tested by providing pairs with a variety of threats to the integrity of the pair (e.g., temporary separations, encounters with strangers). Together, these projects will provide insights into the mechanisms that control responsiveness to infants and adult social partners in a species characterized by high levels of male parenta l care and strong heterosexual relationships.

Exclusive offspring care by females is the norm among mammals, but among a small set of species, males and other group members also play an important and potentially crucial role in the nurturing of dependent offspring. Among marmosets and tamarins, primates of the New World, care by all group members, including the mother, father, and nonbreeding juveniles and subadults, is the norm for social groups. Results from previous NSF funding have revealed important differences in levels of effort in infant care by mothers and fathers, with mothers playing a large role in infant care in the first two weeks of life, and fathers and helpers playing a central role in the 3rd and 4th weeks of infant life and beyond. These changes are associated with variations in testosterone (T) concentrations in mothers and fathers: T is reduced in mothers in the first 2 weeks post partum and in fathers during the second 2 weeks post partum, which corresponds to the highest rates of infant care. The studies outlined in the current proposal will utilize both observational and experimental approaches to the possibility that variation in testosterone concentrations helps regulate responsiveness to infants in marmosets, and whether T mediates a trade-off in effort in infant care versus reproductive and/or aggressive behaviors, which may be incompatible with infant care. The results will shed light on the possibility that complex affiliative and caregiving behaviors in social primates may, in part, be influenced by biological states, as well as experience-related factors.

DESCRIPTION (provided by applicant): Despite mounting evidence that the family is an important mediator of development, two aspects of family life have not been analyzed in depth: the extended family and siblings. Callitrichid primates are characterized by extended family groups, strong emotional attachment between adult males and females, and cooperative infant care. Since the expression of these traits varies widely across family units in callitrichid primates, these species represent ideal models in which to investigate relationships between early experiences in the family and subsequent biobehavioral development. This project will test the general hypothesis that the psychobiological development of infants is not dependent solely on characteristics of the parents and the nature of their interaction with the infants, but rather it should be sensitive to structural and contextual characteristics of the wider family system. The first aim will be to examine infant rearing patterns as a function of inter-individual relationship quality, family demographics, and interactions between the allocation of parental and alloparental care. The second aim is to evaluate the effects of early infant care on psychological and somatic development, and to examine social factors likely to mediate these relationships. The third aim is to investigate whether variation in receipt of caregiving behavior by infants subsequently influences patterns of behavior in adulthood, including heterosexual pair bonding and parental styles. The quality and quantity of care provided to infant marmosets, and developmental outcomes will be examined as families grow from a single breeding pair to an extended family. The impact of family life will be assessed for major developmental milestones, including infant growth and social development, becoming integrated into the larger social group, reproductive and social maturation, pair bond formation and subsequent parental competency. These studies will provide strong tests of the generality of evolutionary models predicting biobehavioral development within the family.

The National Science Foundation (NSF) Graduate Research Fellowship Program (GRFP) is a highly competitive, federal fellowship program. GRFP helps ensure the vitality and diversity of the scientific and engineering workforce of the United States. The program recognizes and supports outstanding graduate students who are pursuing research-based master's and doctoral degrees in science and engineering. GRFP provides three years of support for the graduate education of individuals who have demonstrated their potential for significant achievements in science and engineering. This award supports the NSF Graduate Fellows pursuing graduate education at this GRFP institution.

Project Summary/Abstract The brain neuropeptides oxytocin (OT) and arginine vasopressin (AVP) play important roles in altering neural circuits that regulate social behavior. These ligands regulate normative social function in a host of areas, including social attachment, parental behavior, aggression, and complex social cognition. In pathological brain/behavior conditions, many disorders are characterized by dramatic deficits in the social realm. Knowledge of the way OT and AVP alter cellular function in neurons has the potential to both identify mechanisms that produce social dysfunction and to design compounds that normalize cellular function and behavior. The present project takes advantage of the discovery of novel OT ligand structure, and variation in cellular receptors for OT and AVP in the marmoset, a species that exhibits social monogamy, infant care by males, and a family-like social structure. The first aim will characterize the effects of ligand diversity on the alteration of behavior in a variety of social domains by using in vivo behavioral pharmacology. These domains include male-female attachment, infant care, mate-defense aggression, and social cooperation/altruism. The second aim will quantify the receptor pharmacology and binding characteristics of the ligand variants with the cell membrane G protein-coupled receptors for these related ligands. The final aim will define the specific modifications in G protein-mediated cell signaling processes brought about by these ligands to determine if ligand variation that modifies social behavior does so through specific or `biased' activation of different signaling pathways. Collectively, these three aims will provide important insights into the ways in which neurons and behavior are modified by OT and AVP ligand variants, leading to enhanced knowledge of the neurobiology of social behavior. The project can point to potential options for designing neuropeptide ligand- receptor complexes that could serve as effective tools to treat social dysfunction.