Digital Commons Network^™

Genomic Contributors To Individual Differences In Reward-Related Neural Activity, Lindsay Jane Michalski

Arts & Sciences Electronic Theses and Dissertations

Aberrant reward-related behavior, including impulsive and risk-taking behaviors, is a common feature of externalizing psychopathology (e.g., attention deficit hyperactivity disorder, antisocial personality disorder, and substance-use disorders). Through imaging studies, these behaviors have been linked to dysregulated reactivity within a diffuse reward-related corticostriatal neural network, including the striatum, frontal regions (namely orbital, ventromedial, and dorsolateral cortices), the insula, and the hippocampus. Because variability in risk-taking behavior and related psychopathology is moderately-to-largely heritable (i.e., with estimates ranging from 40 – 80%), a genetically-informed approach is well-positioned to provide valuable insight into the etiology of reward-related neural and behavioral phenotypes that characterize externalizing …

Dynamics And Control In Spiking Neural Networks, Fuqiang Huang

McKelvey School of Engineering Theses & Dissertations

In the brain, neurons (brain cells) produce electrical impulses, or spikes, that are thought to be the substrate of information processing and computation. Through enigmatic processes, these spikes are ultimately decoded into perceptions and actions. The nature of this encoding and decoding is one of the most pervasive questions in theoretical neuroscience. In other words, what are the specific functions enacted by neural circuits, through their biophysics and dynamics? This thesis examines the dynamics of neural networks from the perspective of control theory and engineering. The pivotal concept is that of the normative synthesis of neural circuits, wherein neural dynamics …

A Microfluidic Platform To Investigate The Mechanism By Which Gdnf Overexpression In Schwann Cells Causes Neuronal Axon Entrapment, Ze Zhong Wang

McKelvey School of Engineering Theses & Dissertations

Twenty million Americans suffer from peripheral nerve injury (PNI) caused by trauma and medical disorders, with approximately $150 billion spent in annual health-care dollars in the United States. Even with proper surgical reconstruction, less than 50% of the patients achieve satisfactory functional recovery. The gold standard surgical repair for long gaps (>3cm) is the autologous nerve graft, despite its disadvantages such as donor site morbidity, risk of infection, and increased cost. Alternative methods, such as acellular nerve grafts (ANA), are ineffective for large lesion gaps because of the lack of cells and regeneration factors. Recent efforts have been focused …

Functional Dissociations Revealed By Representational Similarity Analysis Of Color-Word Stroop, Michael Freund

Arts & Sciences Electronic Theses and Dissertations

The color-word Stroop task is often used in cognitive neuroscience as a common platform for both theoretical and experimental approaches to cognitive control. Yet traditionally, there has been tension between these two approaches. Theoretical models of Stroop have focused on representation: for example, how distributed and overlapping representations of the two stimulus dimensions (color, word) are prioritized, and how conflict between these dimen- sions is represented and used to regulate control. In contrast, neuroimaging experiments have primarily focused on ‘univariately’ (uniformly) mapping the effects of conflict to par- ticular brain regions. This focus on univariate changes in brain activity limits …

Determining The Genetic Contributions Of The Williams Syndrome Critical Region To Behavior Using Mouse Models And Human Genetics, Nathan David Kopp

Arts & Sciences Electronic Theses and Dissertations

Williams syndrome is a neurodevelopmental model caused by the deletion of 26-28 genes on chr7q11.23. The loss of these genes affects multiple organ systems resulting in severe cardiovascular disease, craniofacial dysmorphology, intellectual impairment, a specific Williams syndrome cognitive profile made up of deficits in visual-spatial processing with preserved language skills, and a characteristic hypersocial personality. The reciprocal duplication occurs at a lower frequency and manifests with diametric phenotypes to the deletion. This suggests that this locus harbors dosage sensitive genes that play a role in neurodevelopment. Large efforts have been taken to identify which genes are responsible for causing the …

Visual And Chemosensory Pathways Associated With Male Courtship Decisions In Drosophila Melanogaster, Ross Mckinney

Arts & Sciences Electronic Theses and Dissertations

Successful mating in diverse animal species often depends on ritualistic sequences of spatially and temporally coordinated behavioral elements. Yet, the sensory cues and neural circuits that mediate optimal mating display patterns are largely unknown. The courtship ritual in Drosophila melanogaster consists of a well-studied sequence of behavioral elements — including orienting, chasing, tapping, singing, and licking — that are known to depend on several sensory modalities, including both vision and chemosensation. However, the specific sensory inputs utilized by males to direct the spatial and temporal transitions between different elements of the courtship ritual are not well understood. In this thesis, …

High-Density Diffuse Optical Tomography During Passive Movie Viewing: A Platform For Naturalistic Functional Brain Mapping, Andrew Kelsey Fishell

Arts & Sciences Electronic Theses and Dissertations

Human neuroimaging techniques enable researchers and clinicians to non-invasively study brain function across the lifespan in both healthy and clinical populations. However, functional brain imaging methods such as functional magnetic resonance imaging (fMRI) are expensive, resource-intensive, and require dedicated facilities, making these powerful imaging tools generally unavailable for assessing brain function in settings demanding open, unconstrained, and portable neuroimaging assessments. Tools such as functional near-infrared spectroscopy (fNIRS) afford greater portability and wearability, but at the expense of cortical field-of-view and spatial resolution. High-Density Diffuse Optical Tomography (HD-DOT) is an optical neuroimaging modality directly addresses the image quality limitations associated with …

High-Density Diffuse Optical Tomography During Passive Movie Viewing: A Platform For Naturalistic Functional Brain Mapping, Andrew Kelsey Fishell

Arts & Sciences Electronic Theses and Dissertations

Human neuroimaging techniques enable researchers and clinicians to non-invasively study brain function across the lifespan in both healthy and clinical populations. However, functional brain imaging methods such as functional magnetic resonance imaging (fMRI) are expensive, resource-intensive, and require dedicated facilities, making these powerful imaging tools generally unavailable for assessing brain function in settings demanding open, unconstrained, and portable neuroimaging assessments. Tools such as functional near-infrared spectroscopy (fNIRS) afford greater portability and wearability, but at the expense of cortical field-of-view and spatial resolution. High-Density Diffuse Optical Tomography (HD-DOT) is an optical neuroimaging modality directly addresses the image quality limitations associated with …

Visual And Chemosensory Pathways Associated With Male Courtship Decisions In Drosophila Melanogaster, Ross Mckinney

Arts & Sciences Electronic Theses and Dissertations

Successful mating in diverse animal species often depends on ritualistic sequences of spatially and temporally coordinated behavioral elements. Yet, the sensory cues and neural circuits that mediate optimal mating display patterns are largely unknown. The courtship ritual in Drosophila melanogaster consists of a well-studied sequence of behavioral elements — including orienting, chasing, tapping, singing, and licking — that are known to depend on several sensory modalities, including both vision and chemosensation. However, the specific sensory inputs utilized by males to direct the spatial and temporal transitions between different elements of the courtship ritual are not well understood. In this thesis, …

Determining The Genetic Contributions Of The Williams Syndrome Critical Region To Behavior Using Mouse Models And Human Genetics, Nathan David Kopp

Arts & Sciences Electronic Theses and Dissertations

Williams syndrome is a neurodevelopmental model caused by the deletion of 26-28 genes on chr7q11.23. The loss of these genes affects multiple organ systems resulting in severe cardiovascular disease, craniofacial dysmorphology, intellectual impairment, a specific Williams syndrome cognitive profile made up of deficits in visual-spatial processing with preserved language skills, and a characteristic hypersocial personality. The reciprocal duplication occurs at a lower frequency and manifests with diametric phenotypes to the deletion. This suggests that this locus harbors dosage sensitive genes that play a role in neurodevelopment. Large efforts have been taken to identify which genes are responsible for causing the …

Individual Differences In Human Brain Functional Network Organization, Benjamin A. Seitzman

Arts & Sciences Electronic Theses and Dissertations

The human brain is organized at many spatial scales, including the level of areas and systems. Resting-state functional magnetic resonance imaging is a non-invasive technique that allows for the study of areal- and systems-level brain organization in vivo. Over two decades of research has sought to identify and characterize the functional communities that comprise the brain’s network architecture. Consequently, a convergent description of group-average functional network organization in healthy adults has emerged. Recent advances have allowed for the study of such organization in single individuals. Investigation of functional network organization in highly sampled individuals has revealed brain regions that deviate …

Brain Blood Flow And Metabolism: Variable Relationships In Altered Metabolic States, Tyler M. Blazey

Arts & Sciences Electronic Theses and Dissertations

Brain metabolism is usually thought of in terms of energy production. Decades of research has shown that the brain derives the majority of its energy from the oxidative phosphorylation of glucose transported from the blood into the brain. Because of this, cerebral blood flow (CBF), the cerebral metabolic rate of glucose consumption (CMRglc), and the cerebral metabolic rate of oxygen consumption (CMRO2) generally are tightly coupled. Indeed, the coupling between CBF, CMRglc, and CMRO2 is robust enough such that many investigators believe them to be equivalent measures of brain activity. Nevertheless, research over the last few decades has shown that …

Isolating Item And Subject Contributions To The Subsequent Memory Effect, Jihyun Cha

Arts & Sciences Electronic Theses and Dissertations

The subsequent memory effect (SME) refers to the greater brain activation during encoding of subsequently recognized items compared to subsequently forgotten items. Previous literature regarding SME has been primarily focused on identifying the role of specific regions during encoding or factors that potentially modulate the phenomenon. The current dissertation examines the degree to which this phenomenon can be explained by item selection effects; that is, the tendency of some items to be inherently more memorable than others. To estimate the potential contribution of items to SME, I provided participants a fixed set of items during encoding, which allowed me to …

Development Of Enteric Neurons And Muscularis Macrophages, Marina Avetisyan

Arts & Sciences Electronic Theses and Dissertations

The enteric nervous system (ENS) is a complex interconnected network of neurons and glia in the bowel wall that regulates intestinal motility, blood flow, and epithelial function. The ENS also controls aspects of inflammatory signaling within the bowel. To perform these tasks, there are at least 20 types of enteric neuron and four types of enteric glia. Although much is known about early events in ENS development, signals governing the development of specific neuronal subtypes and communication with neighboring cell types within the bowel remain poorly understood. One fundamental hypothesis is that diverse trophic factors support distinct neuronal populations in …

Molecular Mechanisms Responsible For Functional Cortical Plasticity During Development And After Focal Ischemic Brain Injury, Andrew Wiggen Kraft

Arts & Sciences Electronic Theses and Dissertations

The cerebral cortex is organized into functional representations, or maps, defined by increased activity during specific tasks. In addition, the brain exhibits robust spontaneous activity with spatiotemporal organization that defines the brain’s functional architecture (termed functional connectivity). Task-evoked representations and functional connectivity demonstrate experience-dependent plasticity, and this plasticity may be important in neurological development and disease. An important case of this is in focal ischemic injury, which results in destruction of the involved representations and disruption of functional connectivity relationships. Behavioral recovery correlates with representation remapping and functional connectivity normalization, suggesting functional organization is critical for recovery and a potentially …

Typical And Atypical Development Of The Brain’S Functional Network Architecture, Ashley Nicole Nielsen

Arts & Sciences Electronic Theses and Dissertations

The human brain is a complex organ that gives rise to many behaviors. Specialized neural regions cooperate as functional networks that form an intricate functional architecture. Development provides a unique window into how brain functioning and human thinking are affected if the necessary neural features and connections are not fully formed. Similarly, developmental disorders can shed light on atypical trajectories of neural systems that may lead to or be a consequence of symptomatic behavior. A description of the typical and atypical development of functional networks is essential to identify the features of brain organization critical for mature human thinking and …

Coupled Correlates Of Attention And Consciousness, Ravi Varkki Chacko

McKelvey School of Engineering Theses & Dissertations

Introduction: Brain Computer Interfaces (BCIs) have been shown to restore lost motor function that occurs in stroke using electrophysiological signals. However, little evidence exists for the use of BCIs to restore non-motor stroke deficits, such as the attention deficits seen in hemineglect. Attention is a cognitive function that selects objects or ideas for further neural processing, presumably to facilitate optimal behavior. Developing BCIs for attention is different from developing motor BCIs because attention networks in the brain are more distributed and associative than motor networks. For example, hemineglect patients have reduced levels of arousal, which exacerbates their attentional deficits. More …

A Neural Network For Uncertainty Anticipation And Information Seeking, Jensen Kael White

Arts & Sciences Electronic Theses and Dissertations

In a world flooded with ‘click bait’, ‘alternative facts’, and ‘fake news’ one’s ability to seek out, discern, and value information is of utmost importance. Although contemporary phenomena, these cultural ills take advantage of an evolutionarily-preserved drive for humans and nonhuman animals to monitor for and pursue opportunities to gain information. Indeed, in a natural environment where rewards are scarce and can be risky, animals often seek sensory cues as a source of information about future outcomes. Interestingly, humans and nonhuman animals will seek sensory information that provides advance information that predicts an outcome even when this information does not …

Integrative Analysis To Investigate Complex Interaction In Alzheimer’S Disease, Zeran Li

Arts & Sciences Electronic Theses and Dissertations

Alzheimer’s disease (AD) is a neurodegenerative disorder featuring progressive cognitive and functional deficits. Pathologically, AD is characterized by tau and amyloid β protein deposition in the brain. As the sixth leading cause of death in the U.S., the disease course usually last from 7 to 10 years on average before the consequential death. In 2019 there are estimated 5.8 million Americans living with AD affecting 16 million family members. At certain stage of the disease course, patients with inability of maintaining their daily functioning highly depend on caregivers, primarily family caregivers, that incur estimated 18.4 billion unpaid hours of cares, …

Spatio-Temporal Principles Of Infra-Slow Brain Activity, Anish Mitra

Arts & Sciences Electronic Theses and Dissertations

In the study of systems where basic laws have eluded us, as is largely the case in neuroscience, the simplest approach to progress might be to ask: what are the biggest, most noticeable things the system does when left alone? Without any perturbations or fine dissections, can regularities be found in the basic operations of the system as a whole? In the case of the brain, it turns out that there is an amazing amount of activity even in the absence of explicit environmental inputs or outputs. We call this spontaneous, or resting state, brain activity. Prior work has shown …

The Degenerating Star Clock: Circadian Clock Regulation Of Astrogliosis And Implications For Alzheimer’S Disease, Brian Vincent Lananna

Arts & Sciences Electronic Theses and Dissertations

Sleep disruption and circadian dysfunction are common symptoms of aging and neurodegenerative diseases, including Alzheimer’s disease (AD). The molecular rhythms in transcription/translation that govern these behavioral processes are mediated by clock genes and can be abrogated by deletion of the master circadian transcription factor Bmal1 (Arntl). We have shown that disruption of clock gene function in the mouse brain causes astrogliosis, synaptic damage, oxidative stress, and exacerbated neurodegeneration. However, the molecular mechanisms linking the circadian clock to these phenotypes and their implications for AD pathology remain largely unknown. Astrocyte activation occurs in response to diverse insults, and plays a critical …

Approaches To Understanding The Function Of Intrinsic Activity And Its Relationship To Task-Evoked Activity In The Human Brain, Dohyun Kim

McKelvey School of Engineering Theses & Dissertations

Traditionally neuroscience research has focused on characterizing the topography and patterns of brain activation evoked by specific cognitive or behavioral tasks to understand human brain functions. This activation-based paradigm treated underlying spontaneous brain activity, a.k.a. intrinsic activity, as noise hence irrelevant to cognitive or behavioral functions. This view, however, has been profoundly modified by the discovery that intrinsic activity is not random, but temporally correlated at rest in widely distributed spatiotemporal patterns, so called resting state networks (RSN). Studies of temporal correlation of spontaneous activity among brain regions, or functional connectivity (FC), have yielded important insights into the network organization …

Elucidating The Roles Of Astrocyte-Derived Factors In Recovery And Regeneration Following Spinal Cord Injury, Russell E. Thompson

McKelvey School of Engineering Theses & Dissertations

Central nervous system (CNS) injury often causes some level of long-term functional deficit, due to the limited regenerative potential of the CNS, that results in a decreased quality of life for patients. CNS regeneration is inhibited partly by the development of a glial scar following insult that is inhibitory to axonal growth. The major cell population responsible for the formation this glial scar are astrocytes, which has led to the belief that astrocytes are primarily inhibitory following injury. Recent work has challenged this conclusion, finding that astrocyte reactivity is heterogeneous and that some astrocytes are pro-regenerative following injury. Astrocyte transplantation …

Its Skin Is My Skin, Bryan Page

Graduate School of Art Theses

This text examines the complexity of attempting to empathize with bodies that are vastly othered from my own. This broad yet nuanced subject crosses epistemological boundaries and complicates the dualities between both the mind and body, and between the corporeal and the virtual. My desire to better understand the conditions of another’s experience originates from a painful traumatic loss which caused me to feel isolated and incomplete. In response to this suffering, I long to emotionally connect with other beings and create artwork that attempts to bridge the qualia of individual experience.

I am interested in the capacity (or lack …