Pamela S. Hunt - US grants

The age at which alcohol consumption by young adults begins is reported to be ever decreasing. Recent surveys indicate that over 10 percent of 13-year-olds use alcohol and about 70 percent of high schoolers consume alcohol more than once per month. Of these individuals, nearly one- third report binge drinking (defined as consuming more than 5 drinks per occasion) on a weekly basis. In light of these astonishing statistics, our lack of understanding about the underlying causes of adolescent- onset drinking is surprising as well as disturbing. The largest amount of data on this topic has come from studies using selectively-bred strains of rodents showing a clear genetic determinant of alcoholism. However, it is also recognized that genetics alone cannot account for the prevalence of alcohol abuse. Experiential factors must also act, either alone or in concert with genetic predispositions. Due to the early age of onset of alcohol consumption patterns, it is likely that experiences with alcohol occurring very early in life contribute to later acceptance of this drug. There are many ways through which human infants can experience the taste/odor cues of alcohol associated with highly positive social contexts. For example, respired alcohol odor can be detected from conspecifics. Direct exposure to ethanol can also occur through the ingestion of breast milk obtained from an alcohol- imbibing mother. Peak concentrations of alcohol are found in breast milk within 1 hour after maternal ingestion, and alcohol levels in milk are equivalent to maternal blood-alcohol levels. The specific aims of this proposal are to examine these types of early experience and how they might contribute to a young organism's learning positive associations between alcohol and affective context. Our studies will focus on using the developing rat as a model system. The first type of experience with alcohol that will be studied is exposure through the ingestion of alcohol-adulterated milk during a simulated nursing bout. Long-term exposure to this drug during nursing could have serious consequences for later voluntary intake of alcohol. A second type of experience that could lead to modified alcohol acceptance patterns is through social interactions with a conspecific that has just ingested alcohol. It is anticipated that the detection of respired alcohol in this situation will increase later alcohol intake. Both types of early experience with the odor and taste of ethanol could have a substantial and possibly long-term impact on an animal's willingness to ingest alcohol.

Absent from animal research on alcohol-related birth defects (ARBD) is a systematic analysis of ethanol-induced alterations in basic attentional mechanisms. The proposed research will employ measures of the orienting response, a collection of central, autonomic, and behavioral responses elicited by novel stimuli and believed to index the central process of attention in both animals and humans. The long-term objective of the proposed research is to rigorously investigate basic measures of attention, and to determine how they relate to attentional deficits in an animal model of ARBD. ARBD human infants are known to be impaired in the expression of some of these responses, and further knowledge about these measures may ultimately prove useful as part of a neonatal diagnostic for later attentional dysfunction. These experiments will utilize a postnatal alcohol administration procedure that has been effectively used for studying neuroanatomical changes associated with ARBD. Animals will be intragastrically administered alcohol from postnatal days 4 through 9. In all these experiments ethanol-exposed rats will be compared with controls that will either be sham intubated or handled only. The first experiment will involve measuring blood- and brain-alcohol levels on day 9, both in a chronic ethanol group and in a group of acutely-exposed subjects. The design allows for the assessment of metabolic tolerance to ethanol, and will also provide information about alcohol levels achieved - an important determinant of alcohol's teratogenic effects. The second experiment will examine the effects of postnatal alcohol exposure on the functional development of the autonomic nervous system (ANS) at 12 and 16 days of age. A major component of the orienting response consists of a change in the activity of the parasympathetic division. This experiment will examine possible ethanol-induced alterations in baseline autonomic regulation as well as that of the cardiac response to a novel olfactory stimulus. The third and final experiment will assess ethanol- induced deficits in response habituation and short-term retention for both olfactory and auditory stimuli in preweanling animals. Deficits in response habituation and short-term recognition memory have been reported in FAS/ARBD infants. By systematically evaluating orienting responses, habituation and retention a fuller understanding of these responses and how they are affected by FAS/ARBD will be gained.

The age at which alcohol consumption by young adults begins is reported to be ever decreasing. Recent surveys indicate that over 10% of 13- year olds use alcohol and about 70% of high schoolers consume alcohol more than once per month. Of these individuals, nearly one-third report binge drinking (defined as consuming more than 5 drinks per occasion) on a weekly basis. In light of these astonishing statistics, our lack of understanding about the underlying causes of adolescent-onset drinking is surprising as well as disturbing. The largest amount of data on this topic has come from studies using selectively bred strains of rodents showing a clear genetic determinant of alcoholism. However, it is also recognized that genetics alone cannot account for the prevalence of alcohol abuse. Experiential factors must also act, either alone or in concert with genetic predisposition. Due to the early age of onset of alcohol consumption patterns, it is likely that experiences with alcohol occurring early in life contribute to later acceptance of this drug. The long-term objective of the proposed research plan is to understand more fully the mechanisms, behavioral and neurochemical, through which socially mediated increases in ethanol preferences are acquired by preweanling and periadolescent rats. The research will build upon a paradigm recently developed by the PI for rapidly inducing ethanol preferences in preweanling and periadolescent rats. Briefly, one animal (demonstrator) is intragastrically administered a dose of ethanol shortly before a 30-min period of behavioral interaction with the experimental subject (observer). In several experiments we have shown that observers subsequently increase their ethanol intake by up to 75-150% over control levels. Our working hypothesis is that observers detect respired ethanol cues on the breath of the demonstrator in the presence of an endogenous carbon based constituent of rat breath (carbon disulfide), and carbon disulfide promotes the release of endogenous opioids that serve functionally as the reinforcer for the conditioning of preferences for ethanol. To test this hypothesis, we will examine the role of endogenous opioids in promoting the increased ethanol intake patterns through pharmacologically manipulating primarily mu and kappa opioid receptors. The end result of this work will be an increased understanding of the neurochemical and behavioral factors underlying social acquisition of ethanol preferences.

DESCRIPTION (provided by applicant): The overall goal of this research is to expand the investigation of alcohol-induced memory impairments in a rodent model of Alcohol-Related Neurodevelopmental Disorder (ARND). Individuals diagnosed with Fetal Alcohol Syndrome (FAS) or ARND exhibit significant deficits in a variety of memory domains, including explicit, declarative, associative, extinction, and spatial. To date, the study of memory impairments using animal models has focused almost exclusively on tasks that require spatial learning and spatial navigation. The experiments outlined in this research proposal are intended to expand the study of memory deficits by using tasks that have no overt spatial component. We intend to address four specific aims in this research. In all experiments, animals will be administered alcohol during the neonatal period (days 4-9) to model third trimester human exposure. The first aim is intended to further explore short- and long-term nonassociative memory deficits by expanding upon our previous work using habituation of the heart rate orienting response. These experiments will address issues of dose-response functions, limited durations of alcohol exposure, and variations in methodology to promote nonassociative learning. The second aim will examine the relation between nonassociative and associative learning using a Pavlovian fear conditioning procedure and measuring several fear-related conditioned responses (behavior, heart rate, and fear-potentiated startle). The third aim will expand the study of declarative and explicit memory impairments by investigating alcohol-induced changes in trace conditioning and contextual conditioning. In addition, extinction of the conditioned responses acquired in these associative tasks will be evaluated to increase our understanding of alcohol effects on one type of executive function. Finally, the experiments addressing the last aim are geared toward an initial examination of potential behavioral and pharmacological treatments to ameliorate memory impairments resulting from alcohol exposure. The behavioral training techniques are based on transfer of learning from one situation to another, while the pharmacological treatments will include acute administration of cholinesterase inhibitors or chronic choline supplementation to the diet of the offspring. Collectively, these studies will further our understanding of memory impairments observed in humans with FAS or ARND by using tasks with an animal model that fall outside the realm of explicit spatial learning and memory. The potential for amelioration of these cognitive deficits using both behavioral and pharmacological strategies will provide important information regarding treatment approaches for afflicted individuals.

DESCRIPTION (provided by applicant): This R21 exploratory grant application will study a largely neglected and poorly understood principle of the ontogeny of learning---acquisition vs. expression---that will likely yield new insights into the development and neural basis of hippocampus-dependent memory. Research on acquisition vs. expression of delay fear conditioning during ontogeny has yielded novel and unanticipated insights concerning how the amygdala and specific efferent pathways cooperate to generate learned fear. However, other developmental research with other types of learning indicates that acquisition occurs first and expression of this learning emerges later in development. To explore these two possibilities in the case of hippocampus-dependent learning, Drs. Mark Stanton and Jeff Rosen at the University of Delaware; and Dr. Pam Hunt at the College of William and Mary will use behavioral, molecular and neuropharmacological approaches to study acquisition vs. expression of trace fear conditioning in developing rats. In Aim 1, two studies in the Hunt laboratory will explore the role of acquisition vs. expression of learning in the ontogenetic emergence trace conditioning between postnatal day (PD) 23 and PD28 in the rat. In Aim 2, immediate-early-gene expression assays will be performed in the Rosen laboratory on the brains of rats tested behaviorally in Aim 1 to explore the role of developmental differences in neural activity and/or plasticity in hippocampus and amygdala in the ontogeny of trace fear conditioning. In Aim 3, two experiments in the Stanton laboratory will determine the contribution of NMDA- receptor-mediated neural plasticity in dorsal hippocampus to the ontogeny of acquisition vs. expression of visual trace conditioning in PD23-28 rats. This project is innovative because it will be the first to examine acquisition vs. expression of hippocampus-dependent learning during ontogeny using an integrated, multidisciplinary approach. If successful, it will yield novel and important insights that would be pursued more thoroughly in subsequent R01 applications. The project is also significant because it will advance the study of developmental disorders involving aberrant maturation of the hippocampus. For example, Dr. Hunt's laboratory has shown that trace fear conditioning is an especially sensitive outcome measure for studying adverse cognitive effects of developmental alcohol exposure. However, understanding of the neural mechanisms of these effects is hampered by a lack of information on brain-behavior relationships mediating trace conditioning during this period of development. This R21 project seeks to fill that gap. Finally, this project will establish a new multi-investigator collaboration that has strong potential to advance these and other important issues in the developmental neurobiology of learning.

The College of William and Mary is proposing a host of activities to advance women in academic STEM at their own institution as well as two nearby institutions, Richard Bland College and Thomas Nelson Community College. The project has three primary goals and a variety of initiatives to accomplish their goals. The main goal involves career development and mentoring. Initiatives surrounding this goal include an ambitious slate of workshops to promote scholarly writing and professional development. Also a leadership forum and a visiting female scientist program will be initiated. Organic mentoring will be encouraged through one-day annual retreats for all STEM female faculty across the three campuses. The project also includes a variety of research grant opportunities for the STEM women across the campuses. The second goal of the proposal combines efforts to evaluate the effectiveness of the programming described above with research based in the social science literature surrounding the reduction of implicit gender bias. The third goal of the proposal is to increase inter-institutional collaborations among the three participating institutions.

INTELLECTUAL MERIT
This proposal is well written and developed. The initiatives focused on promoting the research agendas of the STEM women are particularly strong and well suited to the needs of less research-intensive institutions. The social science research component of the proposal is very well grounded in the literature and represents a robust, real-life test of possible mechanisms to change implicit bias. The PIs have taken some of the strongest and most successful ADVANCE programming and adapted it appropriately to their context.

BROADER IMPACTS

The collaborative nature of the programming presents a nice opportunity for broader impacts by including STEM faculty at two primarily undergraduate institutions and a community college. The three campuses have over 100 STEM, women, full-time faculty. The social science research is positioned to contribute importantly to the scientific literature on the reduction of implicit bias. The success of these programs, combined with empirical support for a reduction in implicit bias can lead to a replicable model among similar institutions.