Kendra Sewall, PhD - US grants

DESCRIPTION (provided by applicant): This research examines the impact of early nutrition on the cognitive aspects and brain mechanisms of signal processing. Early nutritional deficit is known to impair cognition in humans and animals by constraining neural growth. Signal processing is essential to sociality and is dependent upon three specific cognitive abilities which are likely mediated by separate though interconnected regions of the brain: attention to stimuli, perception of meaningful variation among signals, and memorization and subsequent recognition of familiar signals. Therefore, early nutritional deficit could impair signal processing by constraining the developent and function of brain centers that mediate attention, perception and/or recognition. The proposed research distinguishes among these three hypotheses by manipulating early nutrition in an animal model, zebra finches (Taeniopygia guttata), and comparing nutritionally deprived and control subjects'(1) motivation to attend to stimuli and signal processing behavior through operant tasks, (2) neural activity in signal processing brain centers, as measured by immediate early gene expression and (3) neuron density and volume of signal processing I brain regions. Previous stuides in animal models and clinical studies in humans suggest that early nutritional deficit impairs specific aspects of cognition rather than having general effects on attention. Therefore, early nutritional deficit likely impairs signal processing by constraining the development of brain regions that mediate signal preception and/or memorization. Relevance: This research is directly relevant to human mental health because a number of human social disorders, including autism and schizophrenia, are marked by difficulty processing social cues and early nutrition is implicated in the etiology of these conditions. This work examines the relationship between early nutritional deficit and abnormal sociality rooted in impaired signal processing, a major issue in human mental health.

On every set of genes in every individual (the genotype), the environment exerts its influence to shape observable traits (or phenotypes); this is phenotypic plasticity. Recently, the field of phenotypic plasticity has been split into two subfields: the first is a focus for evolutionary biologists whose goal is to understand how phenotypic plasticity evolved over time, and the other is a focus for physiologists whose goal is to identify the physiological mechanisms underlying the gene-environment interaction. This symposium has three goals aimed at bridging these two subfields. First, the meeting will bring together researchers from the two subfields who otherwise do not cross paths to discuss how their respective theoretical framework can be tested experimentally and how empirical data from one group can give insights to the other. This will help advance our understanding of the costs, benefits, and limitations of phenotypic plasticity and to identify future direction of this field. The second goal is to foster interaction and future collaboration between researchers from the two subfields to bring new approaches and define new directions. The third goal is to encourage participation from early career scientists (e.g., undergraduate and graduate students and postdoctoral researchers) and scientists from underrepresented groups to provide them with an opportunity to receive feedback from senior scientists and identify future mentors. The sequence of talks, alternating between evolutionary biologists and physiologists, and inclusion of designated time for questions and discussion are designed to further cross-disciplinary interactions. Abstracts from all the talks and posters will be publicly available, and papers from the symposium talks will be published in the Integrative and Comparative Biology journal to ensure the dissemination of the symposium.

Non- Technical paragraph

The social environment has important consequences for brain development and learning. This is true for animals, just as it is for humans. The broad goal of this work is to resolve how social interactions can both improve and compromise learning and memory through changes in stress hormone levels. By studying how social experiences impact learning in animals (here, birds) we can understand the costs and benefits of social interactions in a variety of social animals, including ourselves. This project is important to the fields of neuroscience and behavior because we are studying the benefits of social enrichment on brain function and learning. Most prior work has focused only on the negative consequences of social conflict and elevated stress hormone levels. This work is relevant to human society because the basic physiological and brain processes in the bird species to be studied are shared with humans; determining how social conditions impact stress hormones and learning in birds will provide information as to how social interactions impact human health and learning. This experimental work in animals will specifically determine if and how social enrichment could improve learning through effects on stress hormones. Finally, by involving K-12 teachers in summer research experiences and supporting curriculum development and implementation in high school classrooms, this project will be a foundation for training and recruiting students from underserved Appalachian communities to the sciences.

Technical paragraph

Social living is argued to select for enhanced cognition and underlying brain function, because navigating social relationships can require superior attention to social cues and memory of past interactions. Despite extensive work on the role of evolutionary processes in shaping cognition and sociality, few studies have addressed the potential for social conditions to drive changes in cognitive performance and underlying neuroplasticity during an animal's lifetime. Moreover, most studies to date have focused on the potential deleterious effects of social conflict, without considering how social interaction may support cognition and brain function. Social conflict can impair cognition through the effects of elevated glucocorticoids on underlying brain mechanisms. However, the reciprocal hypothesis, that social contact may enhance cognitive performance by maintaining glucocorticoid levels in an optimal range to support cognition and brain function, has not been tested. This project will take the experimental approach of simultaneous manipulation of both social and physiological variables in a social songbird, the zebra finch (Poephila guttata), to resolve the consequences, mechanisms, and developmental origins of individual variation in cognition. This work will move us toward understanding complex relationships among environmental factors and internal regulatory mechanisms. Further, addressing how social contact and underlying glucocorticoids may enhance cognition moves us beyond a historic focus (now well recognized as being flawed) on the impairments caused by this endocrine pathway and builds upon a broadening understanding of the adaptive role of stress. Finally, this project will support the training of K-12 teachers and high school students from underserved rural communities in Appalachia by involving them in the research.

Humans alter the environment by building infrastructure, such as roads and buildings, and also through our presence in wildlands for recreation. Though some species are excluded by human impacts on the environment, many species of wildlife readily modify their behavior to cope with changes such as urbanization. Studying the neural and physiological mechanisms that permit some species to adjust to environmental change addresses the fundamental scientific question of how behavioral flexibility is achieved. Additionally, understanding how species adjust to different aspects of environmental change can inform conservation and management efforts. The proposed work will take advantage of an increase in human recreation in parks in Montgomery County, VA that has been driven by the COVID-19 quarantine to both compare the effects of human presence relative to those of the built environment, and identify brain mechanisms that regulate behavioral adjustments to environmental change in a common song bird, the song sparrow. By working with a local land trust to educate the community about our research this work will benefit the birders and walkers using the park, as well as provide insight into the conservation of wild songbirds.

Human-induced rapid environmental change is a threat to biodiversity and especially songbirds. While some species are in decline because of impacts such as urbanization, others have traits that allow them to cope with changing conditions. Behavioral plasticity is critical for the persistence of species and individuals in the face of rapid environmental change, yet we do not fully understand the mechanisms underlying such flexibility. Moreover, though distinguishing the effects of different types of anthropogenic change is critical for conservation, we do not understand their consequences for wildlife. The proposed work capitalizes on a temporary increase in outdoor recreation in rural environments during the COVID-19 pandemic to determine how increased human presence impacts the behavior and underlying brain mechanisms in free-living song sparrows (Melospiza melodia). Much of what we know about the effects of anthropogenic change on wildlife comes from studies of urbanization. Wild animals living in urban habitats are more aggressive than rural counterparts but the mechanisms regulating these differences remain unclear. Our research group demonstrated that increased territorial aggression in male song sparrows living at our long-term urban study sites is associated with differences in the function of the arginine vasotocin (AVT) system. Therefore, to characterize the contribution of the AVT system to behavioral plasticity in response to anthropogenic change we will compare brain and behavioral measures from adult birds (Aim 1) and hatch-year birds (Aim 2) living in replicate urban habitats, rural habitats with low human presence, and rural habitats with temporary increases in human presence.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.