Joseph Lonstein - US grants

DESCRIPTION (provided by applicant): Adequate parental care of neonates is an indispensable component of successful reproduction in most mammals. However, compared with other behaviors necessary for mammalian reproduction, relatively little is known about the neural pathways underlying parental behavior. This application addresses this issue by investigating the neurochemical substrates regulating maternal care in lactating rats. The main objective is to determine the role of dopaminergic pathways to the medial preoptic area (mPOA) in these behaviors. The mPOA is necessary for some oral components of maternal behavior in rats, such as retrieval of pups, and plays a role in the motivation to act parentally. However, the neurochemical pathways to and from the mPOA underlying these aspects of maternal behavior are completely unknown. It is probable that the hormones of gestation and parturition, as well as sensory cues from pups that dams receive after parturition, influence neurochemical release in the mPOA in a way that promotes maternal performance. One neurochemical in the mPOA that may be necessary for maternal behavior is dopamine. The mPOA has not been one of the neural sites previously examined as a place where dopamine release is necessary for maternal behavior, but this may be a distinct possibility because dopamine release in the mPOA is necessary for other behavioral and motivational aspects of reproduction in rats. It is proposed that dopamine release within the mPOA is necessary for the onset of maternal behavior at parturition as well as for the performance of ongoing maternal behavior in lactating rats. Specific Aim 1 will use high performance liquid chromatography (HPLC) to examine changes that occur in dopaminergic content within the mPOA of female rats during the reproductive cycle and during postpartum interactions with pups. Specific Aim 2 will use retrograde neuroanatomical tracing combined with fluorescence immunocytochemistry for tyrosine hydroxylase, the rate-limiting enzyme necessary for catecholamine synthesis, to determine the source of dopaminergic and other catecholaminergic pathways to the mPOA in virgin and lactating female rats. Specific Aim 3 will examine the effects of pre- or postpartum 6-hydroxydopamine (6-OHDA) lesions of the dopaminergic terminals in the mPOA on the onset and maintenance of maternal behavior in lactating rats. Specific Aim 4 will determine the effects of pharmacological antagonism of specific dopamine receptor subtypes within the mPOA on postpartum maternal behavior in lactating rats. These results will provide much needed insight into how the brain controls nurturant behavior, which is a complex social behavior that is often critical for survival in many mammalian species.

The brain and behavior of males and female mammals often differ in dramatic ways. Exposure to hormones during early development is important for generating neural and behavioral gender differences in many species, but the universality of how and when this occurs is not well understood. This project will examine how early hormones generate gender differences in the brain and social behaviors of prairie voles (Microtus ochrogaster). Prairie voles have an unusual social structure more similar to primates than most other rodents because they are highly social, form life-long monogamous bonds with their mate, and both male and female parents show parental behavior. They are also unique because early hormones appear to influence the development of gender differences in the prairie vole brain and social behaviors through mechanisms different from other rodents. This project will focus on: 1) determining what hormones are secreted, and at what levels, during early development in male and female prairie voles, 2) biochemically characterizing how neurons in numerous developing brain areas metabolize these hormones, 3) examining how manipulations of hormones during early life affect later gender differences in parental and other social behaviors, and 4) exploring how manipulations of early hormones also affect development of brain areas responsible for the display of social behaviors. It is expected that release of a unique combination of hormones in developing males masculinizes their brain and social behaviors, whereas the absence these hormones in females leaves them in a female-like state. This work will advance scientific discovery about how different species employ different developmental mechanisms to generate gender differences in the brain and social/reproductive behaviors. This work will also promote the teaching, training, and participation of a diverse group of undergraduate and graduate students in the laboratory who will spend time researching this area of development.

DESCRIPTION (provided by applicant): High maternal anxiety has tremendously detrimental effects on maternal motivation, mother-infant interactions, and infant development. Although a large number of women experience elevated anxiety after giving birth, the neurobiological events responsible for high postpartum anxiety or its alleviation are very poorly understood. Physical contact with infants can reduce anxiety in postpartum women and other mammals, and is vital for healthy maternal emotional states. I propose to investigate the neural basis of how contact with infants modulates maternal neurochemistry to reduce anxiety. I am specifically interested in the involvement of the ventral bed nucleus of the stria terminalis (vBST) and three of its primary targets (central amygdala, supramammillary nucleus, and periaqueductal gray), which are all traditional components of the neural network regulating anxiety. The vBST has one of the densest noradrenergic innervations of the forebrain, and high noradrenergic tone in the vBST is associated with high anxiety. This is likely due to altered GABAergic and glutamatergic output that directly or indirectly modulates downstream brain areas promoting anxiety. I propose that contact with infants is a natural stimulus chronically down-regulating noradrenergic tone in the vBST. This downregulation of vBST noradrenergic tone is proposed to increase local GABA release, which disinhibits GABAergic projections and/or inhibits glutamatergic projections from the vBST to widespread areas of the brain, resulting in reduced maternal anxiety. Using postpartum laboratory rats as a model, this hypothesis will be tested by: 1) examining the effects of pharmacologically increasing or decreasing noradrenergic tone in the vBST on mothers' anxiety-related behaviors, 2) using in vivo microdialysis to measure extracellular norepinephrine release in the vBST while mothers interact with infants or are exposed to particular sensory cues from their infants, 3) using anatomical tracing to determine the neurochemical phenotype (GABAergic or glutamatergic) of projections from the vBST and other BST subregions to the central amygdala, supramammillary nucleus, and periaqueductal gray and 4) pharmacologically manipulating GABAA receptor activity in these three vBST target sites to determine if GABAA receptor modulation in these areas can prevent or mimic the effects of infant contact on mothers' anxiety-related behaviors. These experiments will be the first to examine the role of norepinephrine in the vBST, and its larger neural network, in the anxiety-reducing effects of infant contact. This information will greatly reinforce the notion that physical contact with infants positively modulates maternal neurochemistry and emotional state, and will improve the diagnosis and treatment of the millions of women and their infants affected each year by postpartum anxiety disorders.

A Research Experience for Undergraduates (REU) Site award has been made to Michigan State University, providing research training for 10 students during the summers of 2013-2015 focusing on the Integrative Biology of Social Behaviors. Participating students will receive 10 weeks of hands-on research experience with projects involving a wide range of model organisms (rodents, carnivores, birds, lizards, salamanders, fish, insects, and digital organisms) and levels of inquiry (molecular, cellular, systems, individuals, populations). Twelve faculty members in the departments of Fisheries and Wildlife, Neuroscience, Psychology, and Zoology will serve as mentors. In addition to their research work, students will benefit from weekly journal clubs and research presentations from the mentoring faculty; will participate in modules related to research ethics, statistics, laboratory safety, applying to graduate school, and careers in the biological sciences; and will participate in outreach activities at a local nature center. At the end of the program, students will present their activities at a university-wide undergraduate research symposium. These activities will sharpen the students' critical and scientific thinking skills, provide a unique opportunity to gain experience with laboratory and field research methods, and help prepare the next generation of researchers studying the biology of social behaviors. Undergraduates entering their junior or senior year will be recruited through personal contacts and by mailings and emails targeted to institutions that can provide the most diverse pool of candidates. Students will be selected based on academic record, any previous research experience, letters of recommendations, and potential for outstanding research in behavioral biology. Students will be tracked in part via Facebook to determine their continued interest in their academic field of study, their career paths, and the lasting influences of the research experience. Assessments of interns and participating faculty members will be comprised of a REU common assessment tool (Undergraduate Research Student Self-Assessment) and other questionnaires, as well as one-on-one interviews that assess interns' topical knowledge in the field, their sense of community, and their knowledge about professional development. More information is available at www.msu.edu/~ibsb, or by contacting the PI (Dr. Joseph Lonstein at lonstein@msu.edu) or the co-PI (Dr. Heather Eisthen at eisthen@msu.edu).

Seasonal affective disorder (SAD) is a major depressive disorder affecting millions of Americans, who suffer recurring symptoms of depression and anxiety in the winter. Empirical evidence suggests that the depressive episodes are caused by insufficient light exposure during the winter months, but how changes in environmental lighting conditions lead to fluctuations in affective state remains largely unknown. This gap in knowledge presents an important problem for successfully identifying risk factors and biological diagnostic markers for SAD, as well as for developing more effective therapeutic strategies. The long-term goal of this research is to understand the brain mechanisms mediating the effects of light on mood and anxiety. The objective of the proposed work is to identify the role of central orexinergic pathways in mediating light- dependent fluctuations in affective state. The proposed work will utilize the diurnal grass rat (Arvichantis niloticus), an animal model of SAD recently developed in the PI's group. There are substantial differences between nocturnal and diurnal species in their circadian rhythms and central responses to light. Therefore, a diurnal model is of crucial importance for elucidating the fundamental mechanisms critically underlying SAD in the diurnal human. The central hypothesis to be tested in this proposal is that light regulates mood and anxiety by acting on brain pathways containing the neuropeptide, orexin. Using the grass rat model of SAD, the proposed work contains three Specific Aims: 1) To determine the effects of light on orexin and its receptors in the diurnal grass rat model of SAD, 2) To test the hypothesis that bright light alleviates depression- and anxiety-like behaviors via enhancing the orexinergic pathways in the diurnal grass rats, and 3) To identify the downstream targets of orexinergic pathways in alleviating depression- and anxiety-like behaviors with a focus on the 5-HTergic dorsal raphe. The project is innovative because it utilizes a novel diurnal animal model and a multi-method approach including cutting-edge molecular biology techniques i.e. AAV-shRNA, to test a novel hypothesis that the orexinergic system mediates the effects of light on mood and anxiety. The proposed work is significant because it is expected to advance and expand understanding of how changes in environmental lighting conditions produce fluctuations in mood and anxiety, which has the potential to translate into better understanding of the neuropathology underlying SAD in humans. Ultimately, such knowledge will contribute to the development of novel preventive and therapeutic strategies for SAD and other mood disorders.      

PROJECT SUMMARY As society seeks to understand the etiology of human emotional and behavioral disorders, increasing attention must focus on the earliest determinants of vulnerability to these disorders, including those existing during prenatal life. Maternal stress during pregnancy contributes to this vulnerability by derailing many aspects of fetal development, including those underlying the infant's later physiological and behavioral responses to stress. Dysregulation of these stress-coping systems is known to put infants at tremendous risk for later emotional and behavioral problems. What remains virtually unknown, however, is how the differential timing of prenatal stress affects the degree of impairment in infants' biobehavioral regulation to stress. In the first longitudinal prospective study of its kind, we propose to use unprecedented high-frequency sampling to measure the occurrence of a common major stressor in a cohort of 335 women starting as early as week 15 of pregnancy, and then determine precisely when during pregnancy (early, mid, late) the stress exposure had the greatest impact on their 6-month-old infants' physiological responses to stress (i.e., hypothalamic-pituitary axis and sympathetic nervous system reactivity) and their behavioral responses to stress. The prenatal stressor we will use as a model is intimate partner violence (IPV). IPV is ideal to study for this purpose because, unlike many stressors studied in previous research on prenatal stress, IPV is an extremely common stressor experienced by pregnant women and its timing during pregnancy can be very precisely assessed. Furthermore, women can experience IPV during pregnancy, postpartum, or both. Therefore, in addition to determining the critical periods during fetal life when exposure to this major stressor is particularly detrimental to later infant stress responsivity, we can determine how those effects compare with postnatal exposure to the same stressor. Based on knowledge about the developmental milestones for the neural substrates involved in the physiological and behavioral responses to stress, we hypothesize in Aim 1 that early gestation stress will have the greatest effects on infant SNS stress responsivity, but that mid-gestation stress will have the greatest effects on infant HPA-axis responsivity and their behavioral responses to stress. In Aim 2 we will examine the maternal HPA axis and SNS functioning during her pregnancy as a mediator of the effects of prenatal IPV on later infant stress responsivity. Knowledge about the sensitive periods to stress that exist within prenatal life will have profound implications for pinpointing the cellular and molecular mechanisms that are derailed in the fetus and responsible for the negative outcomes seen after birth. This knowledge will also greatly inform strategies for prevention and intervention that will help avoid the negative effects of stress during this exquisitely sensitive period for human psychological and behavioral development and, thus, improve the lives of millions of women and their infants.

Maternal bonding is the earliest emotional connection between a mother and her child. When this bond is damaged, there are adverse effects on the mother-child relationship and devastating consequences for the child?s physical, cognitive, and socio-emotional health. Although numerous psychosocial factors have been associated with poor bonding, very little is known about the process by which bonding goes awry. In addition, although research has focused mainly on factors influencing mother-infant bonding after birth, there is strong evidence that mother-infant bonding begins during pregnancy and shows moderate stability through toddlerhood. The purpose of this RO3 project is to test a novel prenatal model of bonding that explicates the association among maternal and fetal biomarkers (ANS/fetal movement), prenatal bonding behaviors, and maternal cognitions about the fetus in mediating the relationship between ANS/fetal movement and bonding behaviors. Importantly, the model proposes mechanisms by which the maternal-fetal bond can become impaired when women experience intimate partner violence (IPV). We will assess 200 participants from our ongoing NICHD- funded RO1 grant, which is exploring the effects of IPV stress during pregnancy and early infancy on a variety of other maternal and infant outcomes. We will begin to test our model during the existing RO1?s third trimester assessment. To do this, we will add assessments of maternal autonomic nervous system (ANS) activity (heart rate and vagal tone) associated with fetal movement, self-reported measures of maternal attributions about the fetus, and observed and self-report prenatal bonding behaviors. We will then add an additional one-month post-birth assessment to determine the process by which the maternal-fetal bond during pregnancy can affect the maternal-infant bond. Knowledge gleaned from this research will be crucial in developing interventions to influence maternal prenatal cognitions about the fetus as a strategy to prevent the devastating effects of problematic maternal-fetal and (later) maternal-infant bonding.

PROJECT SUMMARY Peripartum depression and anxiety are very common, but poorly understood, disorders that negatively affect a tremendous number of women and their infants. Indeed, more than 15% of the 4 million pregnant and recently parturient women in the U.S. each year suffer from depression and at least 10% suffer from anxiety. Selective serotonin reuptake inhibitors (SSRIs) are the most-often prescribed medications for peripartum depression or anxiety. This is despite a lack of knowledge about SSRI's neurochemical effects, or strong evidence for their clinical efficacy as currently prescribed, specifically during this unique period of reproduction. It is unknown if SSRIs affect the pregnant and postpartum brain differently than the non-maternal brain. Reproduction involves some of the most dramatic neurobiological modifications in adulthood. These include the central serotonin (5-HT) systems SSRIs act upon. However, there are no thorough studies of how central 5-HT changes across female reproduction. It is also mostly unknown how prepartum stress, which predisposes women for psychopathology, affects the normative changes in central 5-HT. Thus, it is impossible to determine how, when, and where SSRIs have their greatest capacity to alleviate maternal depression and anxiety. The long-term goal of my research is to better understand how pregnancy and motherhod modify central 5- HT and the downstream consequences for female brain structure and function, which is critical for understanding maternal psychopathology. The objective of this R03 project is to test in detail the hypothesis that reproduction generates a host of changes in the 5-HT system at its source in the midbrain raphe, and in forebrain sites involved in maternal depression and anxiety in a laboratory rat model. I also hypothesize that reproduction affects brain derived neurotrophic factor (BDNF) and its TrkB receptor, which partly mediate SSRIs' neuroplastic and anti-depressive effects. I further hypothesize that pregnancy stress derails these normative brain changes, and that fluoxetine will prevent that derailment. The work proposed will use a variety of research tools (PCR, Western blotting, IHC, HPLC) and is innovative as the first to concurrently measure levels of the 5-HT synthesizing enzyme TPH2, 5-HT and its major metabolite, 5-HT 1A/2A/2C receptors, the 5- HT transporter, BDNF, and TrkB in the female brain through pregnancy and lactation. It is also innovative in that unstressed females will be compared to stressed females, as well as to non-reproducing female rats. This important basic research will contribute to understanding the changes in the central 5-HT and BDNF systems across female reproduction and how they are affected by prepartum stress. More broadly, the results will enhance knowledge about neurochemistry of the maternal brain, and the potential effects of SSRIs during pregnancy and postpartum. This knowledge is highly significant because it has the potential to improve the treatment of millions of women and their infants negatively affected by postpartum depression and anxiety.