Contributions of the superior colliculus to covert decision termination

Many decisions require us to actively interrogate the world using our senses. Based on what we perceive, we may commit to an immediate course of action or plan for future actions. The neuroscience of perceptual decision-making examines how the brain gathers sensory information and uses it to guide behavior. A widely accepted model represents this decision process as the gradual accumulation of sensory evidence until a threshold or criterion is reached. For decisions about the direction of random-dot motion (RDM) stimuli, extensive research has described the mechanisms of evidence accumulation in association areas such as the lateral intraparietal area (LIP). Recent studies have also made progress in identifying the biological basis of the decision threshold. For overt decisions marked by an immediate saccadic response, neurons in the superior colliculus (SC) are thought to set this threshold by initiating eye movements when LIP activity is sufficiently elevated. Additionally, reversible inactivation of SC neurons has been shown to prolong evidence accumulation in LIP, suggesting that SC neurons play a causal role in terminating the decision process. However, it remains unknown whether SC neurons also contribute to covert decision termination, where commitment results in a planned, rather than an immediate, eye movement. To address this gap, I recorded neural activity from two rhesus macaques as they performed a RDM discrimination task, where I varied the length of the stimulus and delay periods from trial to trial. This design required the animals to make a covert commitment to a choice on each trial, which they later reported with a saccade following the delay period. Using high channel-count electrodes, I recorded simultaneously from large populations of neurons in SC, LIP, and the dorsal pulvinar of the thalamus (dPul) unilaterally. In a majority of trials, SC neurons exhibited non-saccadic bursts — bursts of activity not associated with eye movements or specific trial events. The timing of these non-saccadic bursts suggested they might signal the moment of decision termination. Testing this hypothesis, I found that non-saccadic bursts effectively divided each trial into an early deliberation phase, where sensory evidence informed the decision, and a later commitment phase, where further sensory evidence was ignored. Additionally, the timing of non-saccadic bursts in the SC corresponded with the end of evidence accumulation in LIP. Finally, I identified a population of neurons in dPul that may relay this termination signal from SC to LIP. This study advances our understanding of perceptual decision-making by broadening the function of the SC in decision termination. Beyond its established role in terminating overt decisions with an immediate saccadic report, these findings suggest that the SC also contributes to decision termination following covert commitments, where the saccade occurs after a delay. The results have important implications for systems neuroscience by offering a clear example of serial computations occurring across dedicated cortical and subcortical areas to guide flexible behavior. While the path from sensation to deliberation to commitment is far from fully understood, these results lay the groundwork for future research — both to explore the role of additional nodes in the decision-making network and to investigate the local circuits that give rise to distinct functions within each node. In Chapter 1, I provide historical context on the neurobiology of perceptual decision-making, introduce the bounded evidence accumulation model, and discuss its application to both overt and covert decisions. I also motivate the present study by introducing the superior colliculus and its known role in the decision-making network. In Chapter 2, I investigate physiological markers of decision commitment in the SC. I describe non-saccadic bursts, which are physiological events that occur on single trials, and demonstrate how these events relate to covert decision termination. In Chapter 3, I examine how non-saccadic bursts in the SC might be involved in terminating the process of evidence accumulation in LIP and show how neurons in dPul might mediate this effect. Chapter 4 presents closing considerations and outlines directions for future research

Role of preconception nutrition supplements in maternal anemia and intrauterine growth: a systematic review and meta-analysis of randomized controlled trials

Background Impaired intrauterine growth, a significant global health problem, contributes to a higher burden of infant morbidity and mortality, mainly in resource-poor settings. Maternal anemia and undernutrition, two important causes of impaired intrauterine growth, are prioritized by global nutrition targets of 2030. We synthesized the evidence on the role of preconception nutrition supplements in reducing maternal anemia and improving intrauterine growth. Methods We undertook a review of the randomized controlled trials (RCTs) assessing the effect of preconception nutrition supplements on maternal hemoglobin, an indicator to estimate maternal anemia, and markers of intrauterine growth including birth weight, length, head circumference, and small for gestational age. Additionally, we examined preterm birth as an important perinatal outcome. We searched PubMed, CINAHL, Web of Science, Cochrane Central, and Embase. We computed summary mean differences and risk ratios (RR) with 95% confidence intervals (CIs) using random-effect models. We employed I2 and Cochran’s Q test statistics to assess heterogeneity. We used a revised Cochrane risk-of-bias (RoB version 2.0) and GRADE (grading of recommendations, assessment, development, and evaluation) tools to assess the risk of bias and quality of evidence of eligible RCTs, respectively. Results We identified 20 eligible RCTs (n = 27,659 women). Preconception nutrition supplements (iron and folic acid, multiple micronutrients, and a lipid-based nutrient supplement) overall increased maternal hemoglobin by 0.30 g/dL ((0.03, 0.57); I2 = 79%; n=9). However, we did not find a significant effect of the supplements on birth weight (12.25 gm ((− 22.66, 47.16); I2 = 55%; n=10)), length (0.15 cm (− 0.26, 0.56); I2 = 68%; n = 5), head circumference (− 0.23 cm (− 0.88, 0.43); I2 = 84%; n=4), small for gestational age (RR 0.91 (0.80, 1.04); I2 = 31%; n=8), or preterm birth (RR 0.93 (0.69,1.25); I2 = 57%; n=12). In general, the quality of evidence was assessed as very low to moderate. Conclusion Preconception nutrition supplements studied to date appear to reduce maternal anemia. However, it is uncertain whether there are beneficial effects of the supplements on intrauterine growth. Low quality of evidence warrants future well-designed RCTs to produce solid scientific data, particularly of a more comprehensive package of preconception nutrition supplements that include both macro- and micronutrients. Systematic review registration PROSPERO CRD42023464966

Agriculture in a Changing Climate: Applications of Machine Learning and Remote Sensing for Measurement and Adaptation

This work considers how large-scale datasets and novel machine learning methods can be applied to challenges in climate and sustainability, with a particular focus on agriculture. Effectively leveraging these advancements for sustainable development research requires answering two questions: first, how can complex data be translated into useful and accurate information? And second, under what circumstances does this information offer real insight into an important problem? In answer to the second of these questions, the research in the three chapters of this dissertation falls broadly into one of two categories: problems for which high spatial- or temporal-resolution data is necessary but infeasible to collect at scale (Chapters 1 and 3); and problems for which the structure of relationships between features and outcomes is complex, with important non-linearities, interactions, or other nuances that may be overlooked by traditional approaches (Chapters 1 and 2). Both such categories of problem are common in the domain of agriculture, an industry which is critical for food security and economic well-being, but highly susceptible to fluctuations in weather and climate. In Chapter 1, I introduce and validate a method for creating high-resolution estimates of planting and harvest dates for United States crops with satellite imagery. This data is an important input for many research applications, but is only tracked at the state level. The resulting dataset is then used to generate more accurate measures of the weather conditions crops are exposed to during their growing season, and thus more precise estimates of how these conditions impact yields. These estimates suggest a 17% larger impact of extreme heat (>29C) on crop yields than previously documented, with substantial variation in heat sensitivity over the course of the growing season. However, the overall impact of increased temperatures is partially offset by a reduced estimate of growing season duration and a 276% increase in the estimated benefits of warm (10-29C) temperatures. Finally, I present novel evidence that farmers use early planting as a form of adaptation to warming, with planting dates shifting earlier by 0.13 days for each additional 30C day during the growing season. Chapter 2 presents an even more flexible formulation for estimating US crop yields. I introduce a deep learning model that predicts yields directly from daily weather data, and show that it reduces out-of-sample error by 10.7% relative to standard linear modeling approaches. Using interpretable machine learning techniques, I demonstrate that this model learns a number of nuanced patterns consistent with expectations from agronomic theory, including spatial and geographic variation, interactions between weather features, and nonlinearity over weather feature values. Over several simulations, these models estimate future impacts of warming that are two to three times less severe than prior modeling approaches would suggest. However, the complexities of causal identification with highly flexible models mean that these results must be interpreted with caution; primarily, they suggest that estimates of climate impacts may be highly sensitive to feature selection, and to precise trends in warming over the course of the growing season. Finally, Chapter 3 turns to smallholder farms in Kenya, as part of research done with support from Atlas AI. A collection of approaches for real-time yield monitoring at the field level are introduced and tested, using satellite-based assessment of vegetation health. I discuss a remotely-sensed proxy for crop yields for use in environments where reliable ground truth data is unavailable, and present a model that can capture 73.5% of variation in this yield proxy by roughly 6 weeks post-planting. A range of approaches are evaluated for incorporating location- and crop-specific features, handling low volumes of training data, and adjusting for variable timing of satellite imagery collection. Taken together, these chapters demonstrate the value of remote sensing and machine learning for understanding the impacts of climate on crops and identifying strategies for adaptation. They also emphasize the complementarity between novel machine learning approaches and traditional statistical and economic methods: in Chapter 1, for example, satellite imagery is used to generate a novel dataset for analysis with more standard models; and in Chapter 2, I present a non-parametric approach to feature discovery for future causal inference work. Finally, these chapters demonstrate that estimates of climate impacts can be highly sensitive to what features are used and how they are encoded; this underscores the importance of careful consideration in constructing accurate feature inputs, and caution in interpreting the results of any one model

Defamiliarizing the Voice: Approaches to Vocal Composition in the Music of Anna Korsun, Charmaine Lee, and Anna-Louise Walton

The voice is a unique instrument which is integrated into the body and culturally trained from birth. Due to its distinctive identity, many composers have the instinct to obfuscate its humanness in search of an instrument more malleable to their creative pursuits. I present Viktor Shklovsky’s concept of defamiliarization, "to increase the difficulty and length of perception,” as a framework for this approach to the voice. I posit that making the voice unfamiliar or strange provokes a heightened state of listening. By contemplating whether a sound’s source is human or not, the listener perceives the voice anew. I look first to Anna Korsun’s piece Ulenflucht for twenty singing and playing performers, which integrates primal vocal techniques with animal calls and bird whistles to create an imagined environment in which the voice is one of many creatures. I then turn to the vocal improvisations of Charmaine Lee, whose intimate integration of her voice with technology blurs the boundaries between human and machine. Finally, I relate the music of Korsun and Lee to one of my pieces, the deep glens where they lived for vocal sextet, which mediates the voice with PVC pipes and close microphone techniques. This music explores the rich and fragile nature of the human voice, and in so doing reframes, reimagines, and redefines it

“I’m Already Channeled Out by the World, Lemme Go Ahead and Get Drinking”: Sex Offender Registration and Notification Policies as Social Determinants of Behavioral Health

As of 2017, there were approximately 861,000 people in the U.S. required to register under sexual offender registration and notification policies. While evidence indicates that these policies do not deter sexual offending or prevent recidivism, these policies do have significant effects on the wellbeing of registrants and their communities. Registrants face numerous policy and legal proscriptions, such as residency restrictions that prohibit them from living in proximity to schools or public spaces, exclusion from public housing and shelters, and ineligibility for federal funds directed towards reentry, vocational, or social services. Moreover, they experience intense stigma and alienation, which often manifest as abandonment by social networks, exclusion from community spaces, and overt discrimination and harassment. Many of the severely destabilizing collateral consequences of sex offender registration policies are also known risk factors for substance use. These policies and restrictions may therefore create or exacerbate a substance use risk environment and increase the likelihood of substance-use-related harms, including interpersonal harms. However, no public health research has directly examined relationships between sex offender registration policies and substance use related harms. This dissertation identifies and addresses this gap in knowledge through a rapid review of the collateral consequences literature, followed by studies based on 44 qualitative interviews with people required to register in Philadelphia and the 20 qualitative interviews with professional stakeholders who work with them. The rapid review yielded 42 peer reviewed studies and governmental reports documenting the collateral consequences of sex offender registration and notification policies. Consequences typically fell into the categories of housing, employment, education, relationships, mental health, criminal justice, stigma, and safety. Housing was the most frequently reported barrier, closely followed by employment and stigma. Only one study alluded to substance use, and no studies focused their attention on substance use related harms. Most studies were published in criminal justice and/or forensic psychology journals, and no literature was published in public health journals. Six key themes emerged from 20 qualitative semi-structured interviews with criminal legal, substance use, and forensic stakeholders who work with people required to register in Philadelphia. These themes described how 1) “sex offender” is an extremely stigmatized and villainized identity, 2 & 3) how sex offender registration related restrictions transform the social and material context of reentry, 4) how both the formal restrictions and the labeling have detrimental impacts on mental health and self-concept, 5) how these material and psychosocial consequences of SORN increase substance use risk and restrict access to court-referred drug treatment, and 6) how the overall landscape has dangerous and destructive implications, especially for overdose risk. Forty-four interviews with adult men required to register in Philadelphia yielded similar themes that broadly illustrated the challenging reentry landscape faced by people required to register, as well as the impacts of sex offender registration policies on health and wellbeing. These themes documented how 1) sex offender registration policies enact formal barriers—such as residency restrictions--that cultivate a restricted reentry landscape, 2) how registration policies and the sex offender label have wide ranging and significant interpersonal effects, 3) how both the formal and informal barriers impact the mental health of people required to register, and 4) how all of these consequences impact substance use related harms. Results suggest that sex offender registration and notification laws operate as social determinants of poor health for registrants and are previously unstudied collateral consequences of sex offender criminalization. These findings provide evidence for social service providers, funders, policy advocates, and officials on the need to reform harmful and ineffective policies and improve access to treatment services for people required to register

Baton Rouge Mental Health Resource Mapping: Strategies for investing in long-term resilience | Community Profile, Contextual Analysis, and Findings and Recommendations

The resilience of a community to the disruption of a disaster depends substantially on its systems of support, among them inherent pre-disaster processes in management and governance, as well as resource availability and local context. In general, these systems of support may include resources provided by formal governmental agencies, intergovernmental entities, non-profit or non-governmental organizations, and grassroots efforts such as mutual aid working groups or other community-led activities. After a disaster in a domestic setting, a community often receives mental health and psychosocial support resources, which may include individual therapy, group discussions, or morale-focused services to help address basic needs such as shelter, food, and safety. These are provided by local and regional actors but may be supplemented with a surge of external response actors who help fill a short-term need. Baton Rouge, Louisiana, in addition to serving as a major relocation region for Hurricane Katrina survivors, has experienced its own repeated exposure to hurricanes, major floods, and toxic environmental contaminants. The genesis of this research study, sparked by an observation by a local philanthropic organization, is rooted in the assumption that continued investment in “reactive” mental health services will not lead to lasting and sustainable improvements in community-wide mental health and resilience. In an effort to gain a deeper understanding of the current state of mental health services in East Baton Rouge Parish, an assets-based service map has been designed to identify key community strengths that may be built upon. Synthesizing a robust mapping of mental health service assets requires developing an awareness of organizations and key stakeholders, as well as an understanding of the capabilities and capacities of their respective services. To accomplish this goal, the National Center for Disaster Preparedness (NCDP) at Columbia University's Columbia Climate School implemented a multifaceted asset- and resource-mapping project that leveraged publicly available information, administered an organizational assessment, and conducted key informant interviews with mental health and psychosocial support practitioners to collectively provide a rich understanding of the existing resources and capacities in the Baton Rouge area, with children identified as a special area of focus within the broader system(s) and stakeholders. The report is structured into three parts. Part 1 is a Community Profile which provides basic demographics, economic drivers, health indicators, and other useful background information. Part 2 is a Contextual Analysis of a deep review of this social and historical context as they pertain to mental health and resilience of this region. Part 3 presents study findings from a series of key informant interviews and ultimately a series of informed recommendations for long-term investments for community-wide mental health and well-being

The Effects of Adaptive Leadership and Stakeholder Engagement on the Strategic Planning Process: A Single Case Study

As the landscape of higher education continues to evolve, the findings from this dissertation underscore the necessity for institutions to adopt strategic planning processes that are reflective of their diverse communities and allow for leadership to be adaptable to changing circumstances. The emphasis on adaptive leadership and stakeholder engagement as crucial components of successful strategic planning highlights the importance of flexibility, inclusivity, and effective communication in navigating the complexities of higher education. The challenges identified in this study, including difficulties in communicating the strategic plan, balancing stakeholder demands with institutional priorities, and avoiding planning fatigue by maintaining momentum and engagement, are critical areas that require attention. Addressing these challenges through best practices such as creating inclusive processes, ensuring clear communication, promoting adaptability, and managing stakeholder expectations can enhance the effectiveness of strategic planning efforts. Future research in this area presents an opportunity to expand our understanding of strategic planning in higher education. By exploring strategic planning across different types of institutions, incorporating quantitative methods, conducting comparative studies, and focusing on the implementation phase, scholars can build upon the findings of this study. Such research can contribute to the development of strategic planning processes that are more effective, inclusive, and capable of adapting to the evolving needs of higher education institutions. In conclusion, this dissertation contributes to the body of knowledge on strategic planning processes in higher education by highlighting the significance of adaptive leadership and stakeholder engagement. By embracing these elements, higher education institutions may be more able to develop strategic plans that both meet their goals and foster a sense of ownership and commitment among their stakeholders. As higher education institutions continue to face challenges and opportunities in a rapidly changing world, the insights from this study can serve as a guide for developing strategic plans that are resilient, inclusive, and forward-looking

Pieces of a Park: Connecting Art, Cultural Heritage, and People at Mount Rainier National Park

The role of art in and about national parks is omnipresent, yet it remains a niche research area. This thesis seeks to further and nuance this area of research by placing the discourse within the purview of historic preservation. The primary argument of the thesis is that art helps socially construct the cultural heritage of national parks and ascribes values to them. These values then allow the public to connect, mentally and emotionally, to national parks, and, in that way, art advocates for their historic preservation. The three primary research questions are: (1) How does art influence the social construction of national parks as cultural heritage? (2) What values are ascribed to national parks through art? (3) How does art affect advocacy and contribute to historic preservation decisions? To allow for in-depth research, one national park is primarily focused on. Mount Rainier National Park in Washington state serves as the case study and was selected based on its influence, representativeness, and lack of prevalence in current historic preservation scholarship. After theoretical background and a historical analysis, the works of three different kinds of artists at Mount Rainier are examined. The writings of John Muir, the photographs of Asahel Curtis, and the sketches of Dee Molenaar, all provide insight to how art socially constructs the cultural heritage of Mount Rainier National Park, ascribes values, and, in turn, advocates for its historic preservation

Genoa: A Circular Path Towards Resilience

The municipality’s planning documents, mainly the “Lighthouse Genoa’s City Strategy” and the “Genoa 2050 Action Plan for a Lighthouse City”, were developed to increase detailed analysis referring to the following impacts and propose actions and plans to mitigate them: - effects on human health that could increase mortality and morbidity related to heat waves and warm spells stress, diseases and mortality from air pollution, allergic disorders, diseases related in change of vector-borne, water-borne and food-borne disease spreading; - change on the hydro-geological regime with potentially increased risk of flash-flood in the 65 river basins, and widespread related risk of landslides; - increased risk of forest fires and wild-urban interface fires in the most critical areas of urban boundaries; - increased occurrence of extreme weather events combined with sea level rise, and related risk of coastal flooding and coastal erosion; - losses in key economic sectors, such as energy, tourism, declining productivity in fishery and agriculture, infrastructure, transport and human activities, human settlements and socio-economic activities as a whole. The Lighthouse Strategy was organized according to the three major assets (green, grey, soft), characterized by key elements and by their own particular themes. Needs were investigated, and solutions, methods, and actions were developed to support and anticipate changes, and to enable the city’s necessary transformation process. Keywords: Transformative actions, multi-level governance, capacity buildin

Connecting Place and Purpose: Land Grant Institutions, Cooperative Extension, and Urban-Rural Linkages

Founded under the Morrill Act in the late nineteenth century, land-grant universities and their affiliated Cooperative Extension programs have historically concentrated their research, community engagement, and economic development efforts on rural communities and challenges. In recent years, however, calls to expand their presence and impact in urban and metropolitan areas—framed as essential for maintaining relevance amidst rapid urbanization—have gained significant momentum. How might these universities harness their longstanding tradition of serving the “non-university public” through Cooperative Extension to meet this mandate? And further, how can physical campus planning and Cooperative Extension programming coalesce to strengthen urban-rural connectivity in and around land-grant campuses? Drawing on case studies of four major land-grant universities—Rutgers University–New Brunswick, The Ohio State University–Columbus, the University of Nebraska–Lincoln, and the University of Minnesota–Twin Cities—this Capstone investigates how planners, Extension professionals, and city planners interpret and operationalize the land-grant mission in metropolitan contexts. Through semi-structured interviews that accompany this case study analysis, the research reveals disconnects between Cooperative Extension and campus development strategies, as well as underutilized opportunities to foster reciprocal relationships between urban and rural communities. Findings suggest that while many land-grant universities recognize the need to adapt to changing demographics and geographies, institutional silos, resource constraints, and governance fragmentation hinder integrated approaches. The project argues for a more intentional alignment of spatial planning and public service mandates—ones that are forward-looking while also reckoning with the land-grant system’s deeply colonial origins—to enhance its relevance, equity, and impact in the twenty-first century