Social and Behavioral Sciences Commons^™

Neural Mechanisms Of Lexical Semantics: Investigating The Roles Of Hubs And Distributed Action-Perception Systems, Nicholas Andrew Riccardi

Theses and Dissertations

Understanding the meaning of words and concepts is vital for communication, forming relationships, and navigating everyday life. Loss of this knowledge through brain damage can have drastic consequences for one’s health and well-being. It is therefore important to learn how this information is organized anatomically in the brain. In this dissertation, I report a series of structural and functional neuroimaging studies in healthy adults and survivors of stroke seeking to understand how lexical semantics are represented. Specifically, I used a variety of tasks to examine the contributions of putative ‘hubs’ and distributed action-perception systems. Results indicated that damage or disruption …

Using Factor Mixture Modeling To Counter Faking, Raul Corrêa Ferraz

Theses and Dissertations

Self-reports (SRs) of typical behavior are often the only existing feasible method to gather data on important drivers of human performance. In applications such as personnel selection, SRs are vulnerable to intentional distortions, often referred to as faking. A review of the literature suggests that so far, the methods proposed to address faking are unsatisfactory. In a recent breakthrough, Pavlov et al. (2019) showed that high-stakes scale scores are best modeled as a function of a) propensity to fake, b) honest scores, and c) the interaction of these two terms. Pavlov et al. did not, however, propose any method to …

Cognitive Consequences Of Covid-19 Infection And Quarantine-Induced Social Isolation: Hope For The Young And Mildly Infected, Kristin Nickole Kirchner

Theses and Dissertations

Coronavirus disease 2019 (COVID-19) has infected over 539 million individuals worldwide, and initial research supports the possibility that COVID-19 may damage the central nervous system either directly or indirectly. Neurological signs and noted cognitive deficits observed in even mildly infected patients are a cause for concern for those infected by COVID-19; the effect of social isolation on the central nervous system is also of interest. The present study sought to determine the extent of these potential cognitive deficits in a young and mildly infected sample of college students. Participants completed an extensive survey assessing their experience with COVID-19 and any …

S-Equol: A Novel Therapeutic For Hiv-1 Induced Gut Dysbiosis, Mason T. Rodriguez

Theses and Dissertations

HIV-1 infection affects approximately 38 million people around the world. The advent of cART has greatly improved the quality of life of infected individuals; however, roughly 50% of these individuals will still experience HIV-1 associated neurocognitive disorders (HAND). Additionally, the gut microbiome has been reported to be dysbiotic in HIV-1 infected individuals, regardless of adherence to cART. Current research has pointed to the gut-brain-microbiota axis as a potential target to treat both cognitive deficits and microbial changes. The present study investigated S-equol (SE) as a potential therapeutic for HAND by modulating the gut microbiome. The study included 21 HIV-1 Tg …

Testing Models Of Context-Dependent Outcome Encoding In Reinforcement Learning, William M. Hayes Iv

Theses and Dissertations

Previous studies of reinforcement learning (RL) have established that choice outcomes are encoded in a context-dependent fashion. Several computational models have been proposed to explain context-dependent encoding, including reference point centering and range adaptation models. The former assumes that outcomes are centered around a running estimate of the average reward in each choice context, while the latter assumes that outcomes are compared to the minimum reward and then scaled by an estimate of the range of outcomes in each choice context. However, there are other computational mechanisms that can explain context dependence in RL. In the present study, a frequency …

Impact Of Number Of Alternatives And Spatial Arrangement On Decoy Effects, Jacob M. Stanley

Theses and Dissertations

The way in which people make decisions is largely guided by the context of the choice set. Choice sets that contain decoy alternatives can result in context effects that violate rational principles of decision making. Most studies on contextual choice manipulate preference among two alternatives in the context of a decoy using three option choice sets. However, many real-world decisions are made among choice sets with many more than three alternatives, such as in online shopping. We tested for attraction and compromise decoy effects in choice sets with varying numbers of alternatives by using a within-subjects preferential grocery shopping task. …

Dreadds Modulation Of Operant Behavior In Male And Female Hiv-1 Transgenic And F344/N Rats, Jessica Illenberger

Theses and Dissertations

The neurobiological processes which determine the choice between 2 (or more) reinforcers are unidentified despite the remarkable benefits which could result from better understanding or control of such processes. Most prominently, reducing choices to pursue drug over non-drug reinforcers could curtail the development or continuation of drug dependence. Likewise, increasing goal-directed behavior in single-schedule and choice settings may alleviate some of the consequences of apathy, a reduction in goal-directed behavior which can occur with neuropathologies including HIV-associated neurocognitive disorders. Dysregulation of the mesolimbic circuit, connecting the ventral tegmental area to the nucleus accumbens, has been implicated in both drug dependence …

Treatment Of Hiv-1 Associated Neurocognitive Disorders Through Mechanisms Of Neurogenesis With 11-Hour Voluntary Running Wheel Exposure, Alex Steiner

Theses and Dissertations

Individuals with HIV-1 taking combined antiretroviral therapy (cART) live longer with less morbidity associated with the infection. The increase in lifespan has created a critical need for the deterrence of HIV-1 associated neurocognitive disorders (HAND) reported in the aging population. Previous reports indicate that the HIV-1 infection may cause impairment in neurogenesis, leading to many of the cognitive deficits seen. The current paper proposes that exercise, as defined by voluntary wheel running, would be a potent inducer of neurogenesis that results in the neuro-restoration of CNS properties and cognitive functioning. Each animal had free access to 11-hour nocturnal wheel-running seven …

Escitalopram Treatment To The Hiv-1 Transgenic Rat: Spine Dynamics, Telomere Quantification And Neurogenesis, Adam Ray Denton

Theses and Dissertations

HIV is a serious viral infection that persists in the brain despite treatment. Approximately half of all seropositive patients will experience some degree of comorbid depression, as well as HIV associated neurocognitive disorders. The present research sought to evaluate the therapeutic efficacy of escitalopram, a selective serotonin reuptake inhibitor in ameliorating neuroanatomical and biochemical markers associated with HIV infection. The central purpose of this research is to characterize the effects of escitalopram treatment upon dendritic spine proliferation in the nucleus accumbens. Previous research has consistently demonstrated impaired synaptodendritic integrity in this region, with underlying mechanisms remaining unclear. A secondary focus …

Application Of The “Idisco” Full-Brain Tissue Clearing Method: A View Of Dopamine And Inflammation In The Hiv-1 Transgenic Rat, Kristin Nickole Kirchner

Theses and Dissertations

The iDISCO (immunolabeling-enabled three-dimensional imaging of solvent-cleared organs) method is a quick, inexpensive, and easily adaptable tissue staining and clearing procedure that allows neuroscientists to study a protein of interest in a whole, unaltered tissue sample. While the iDISCO method was initially tested and validated for mice embryos and brains, the current experiment sought to adapt the method for use in the rat using HIV-1 transgenic (Tg) rat brain tissue. Antibodies for tyrosine hydroxylase and Iba-1 were validated in the HIV-1 Tg rat and in F344/N control rats using iDISCO. Confocal images were taken of tyrosine hydroxylase positive neurons in …

The Behavioral And Neural Effects Of Audiovisual Affective Processing, Chuanji Gao

Theses and Dissertations

In everyday life, we receive affective information from a multisensory environment. What we see and what we hear jointly influence how we feel, think and act. Outstanding questions still remain about the essential behavioral and neural mechanism underlying how we combine visual and auditory affective signals. In this dissertation, I report a series of behavioral, EEG and fMRI experiments addressing this question. I found behaviorally there are congruency, visual dominance, and negativity dominance effects. Using ERPs, I showed that these behavioral effects can map onto different time course in audiovisual affective processing. Time-frequency analyses of EEG data showed that there …

Testing For Differential Attention To Features In Evaluative Conditioning, Christine E. Weber

Theses and Dissertations

One eye tracking and one behavioral experiment examined the possible roles of contingency awareness and attention to stimulus features in evaluative conditioning. These experiments tested whether evaluative conditioning altered the saliency of positive and negative features in consumer products (Study 1) and attitudinal responses to ambivalent pictures (Study 2). Based on the conceptual categorization model, pairing of ambivalent conditioned stimuli with liked or disliked unconditioned stimuli was predicted to result in enhanced attention to affectively congruent features. Study 1 tested this prediction by recording eye movements to determine how attention to features and responses to ambivalent stimuli were altered as …

Motivational And Physiological Dysregulation Due To Development And Onset Of Obesity Via Melanocortin 4 Receptor +/- Haploinsufficiency, Alex Steiner

Theses and Dissertations

Obesity is one of the leading most health risks around the world, being especially problematic in the United States. A combination of high-fat diets and genetic abnormalities are to blame for the ever-growing number of obese individuals.

Melanocortin 4 receptors are vital for regulating energy expenditure and feeding behaviors; mutations of the receptors have been found to be the leading monogenetic cause of obesity. Using MC4R +/- haploinsufficient rats being fed a range of dietary fat, we investigated the physiological and motivational differences using a locomotor task, an operant task with fixed and progressive ratios, as well as a distraction …

Building A Statistical Model Of The Drivers Of Self-Presentation, Kathleen Jocoy

Theses and Dissertations

The attempt to maintain a consistently positive public image is known as self-presentation; however, the structure of self-presentation has not been adequately explored. This paper aimed to identify a theory-based model for self-presentation by examining the relationship between personality traits and utilization of self-presentational behaviors. A review of the literature suggested self-presentation would be best modeled with a second order two-factor model with second order factors of Evaluation and Response. The second order factor of Evaluation is expected to explain the first order factors Perceived Anonymity, Sociability, and Communality while the second order factor of response is expected to explain …

Inhibition Of Return In Visual Search: Disentangling Overlapping Contributions With Event-Related Potentials, Allison Michelle Pierce

Theses and Dissertations

Inhibition of return (IOR) refers to the finding that responses to previously attended locations are slower than those to previously unattended locations. Despite over 30 years of research on IOR, there is still no consensus in the field regarding what the underlying mechanism of this effect is. Although IOR is traditionally studied within spatial cueing paradigms, this effect is thought to reflect a mechanism that facilitates efficient visual search. The following studies explored the hypothesis that multiple processes contribute to the IOR effect in visual search and examined whether these are the same processes that result in IOR in cueing …

Behavioral And Voltammetric Analysis Of Chronic Escitalopram Treatment To The Hiv-1 Transgenic Rat: Implications For Comorbid Hiv-1 And Clinical Depression, Adam R. Denton

Theses and Dissertations

HIV-1 infection is a serious condition affecting approximately 37 million individuals. Between 30% and 60% of seropositive individuals will develop symptoms of clinical depression. These individuals are five times more likely to commit suicide than non-seropositive clinically depressed patients. Dysfunction in serotonergic and dopaminergic transmission has consistently been implicated in the pathogenesis of depression. Specifically, dysfunction in the prefrontal cortex and in the nucleus accumbens core region have been shown to be underlying factors in the trajectory of depression. Given these underlying neurological features, the present research employed behavioral testing and electrochemical recording in an attempt to elucidate the therapeutic …

Exercise As A Therapeutic For Hiv-1-Associated Neurocognitive Deficits, Michael N. Cranston

Theses and Dissertations

Human Immunodeficiency Virus (HIV-1) afflicts nearly 38 million individuals worldwide (Joseph et al., 2013; “WHO | HIV/AIDS,” 2016). Despite the reduction in disease mortality due to increased use of antiretroviral medication, HIV-1 associated neurocognitive disorder (HAND) affects approximately 50% of HIV infected individuals (Antinori et al., 2007; Castellon, Hinkin, Wood, & Yarema, 1998; Castelo, Sherman, Courtney, Melrose, & Stern, 2006; Cysique & Brew, 2009; Heaton et al., 2011, 2015). The brain itself is particularly sensitive to HIV-1 related viral proteins and viral infection (Masliah, DeTeresa, Mallory, & Hansen, 2000), thus, it is vital to empirically examine potentially effective therapeutics which …

Advancing Understanding Of Dynamic Mechanisms In Onset To Event Models: Discrete Time Survival Mediation With A Time Variant Mediator, Heather Lasky Mcdaniel

Theses and Dissertations

Integrating discrete time survival and mediation analytic approaches, discretetime survival mediation models (DTSM) help researchers elucidate the impact of predictors on the timing of event occurrence. Though application of this model has been gainful in various applied developmental and intervention research contexts, empirical work has yet to consider how DTSM models operate with a mediator that has a varying effect over time. The importance of examining this situation has important impacts for application of the model, given more complex statistical models are required, and subsequent interpretation of model parameters differ from the basic DTSM model. The overarching purpose of this …

Neurochemistry, Physiology, And Behavior In A Model Of Gulf War Illness, Victoria A. Macht

Theses and Dissertations

Upon returning from the first Gulf War, soldiers cited a plethora of unexplained physical and cognitive deficits which have since been termed Gulf War Illness (GWI). Presentation of GWI is positively correlated with pyridostigmine bromide (PB) use, which was prophylactically administered to soldiers in response to threats of chemical warfare. To test the overarching hypothesis that PB interacted with stress of deployment to alter neural, endocrine, and immune systems, the following studies used a 2×2 rodent model with 14 days of drug treatment (vehicle; PB) and 10 days of repeated restraint stress (stressed) or non-stressed-control conditions. Results indicate that PB …

Evaluative Conditioning Of Product Preferences: An Eye-Tracking Perspective, Christine E. Weber

Theses and Dissertations

In evaluative conditioning, the affective response toward a neutral stimulus is altered by pairing it with a positive or negative stimulus. One behavioral and two eye tracking studies were conducted to investigate how evaluative conditioning operates on consumer preferences by pairing neutral products with valenced music and using multiple product exemplars and test trials in order to test evaluative effects at the individual level. Study 1 showed an overall positive effect of evaluative conditioning on choice and liking ratings, although there were individual differences in the magnitude and direction of the effect. Study 2 found significant results at the individual …

Questioning The Modality Of The Occipital Lobe, William J. Brixius

Theses and Dissertations

This dissertation explores the occipital lobe’s response to non-visual inputs, and whether this responsivity partitions into separate localization and identification pathways as seen with visual inputs. We hypothesized that occipital areas may merely prefer visual inputs, while maintaining similar task-based sensory recruitment in response to other senses. Our secondary hypothesis was that the robust occipital activation seen in late-blind participants stems at least initially from standard connections present even in the typically sighted, and that these standard connections are functionally utilized by the typically sighted in spatially relevant non-visual analyses. Our initial literature review supported our hypotheses that the occipital …

Scene Search Guidance Under Salience-Driven And Memory-Driven Demands, Jenn Ha’Aheo Olejarczyk

Theses and Dissertations

Visual search involves selecting relevant information while ignoring irrelevant information. Most search models predict what relevant features attract gaze; yet few consider search guidance from previous knowledge of scenes. This dissertation used eye movements to examine the guidance of attention when an immediate or delayed distractor appeared during novel and repeated searches.

The experiments showed efficient search for repeated scenes, a classic result of contextual cueing. During repeated searches, an immediate attentional bias was found for distractors close to the target location. Automatic and controlled selective attention processes, measured using the antisaccade, were found within search behavior. The final experiment …

Dimensionality And Instrument Validation In Factor Analysis: Effect Of The Number Of Response Alternatives, Alexander G. Hall

Theses and Dissertations

Despite the great prevalence in both research and application of Factor Analysis (FA), widespread misinterpretation continues to pervade the psychological community in its application for the development and evaluation of psychometric tools. Fundamental measurement questions such as the number of response alternatives needed, and the power to detect poor model fit in non-normal or misspecified data, still remain in need of further investigation. For example, the power of the chi-square statistic used in structural equation modeling decreases as the absolute value of excess kurtosis of the observed data increases. This issue is further compounded with discrete variables, where increasing kurtosis …

Development Of Brain Functional Connectivity And Its Relation To Infant Sustained Attention In The First Year Of Life, Wanze Xie

Theses and Dissertations

This dissertation project studies the development of infant sustained attention and its relation to brain functional connectivity from 6 to 12 months of age. Chapter 1 is a general introduction of the dissertation project. Chapter 2 is a review of the existing literature on the development of infant sustained attention. This chapter includes theories on infant sustained attention and findings from studies using behavioral and psychophysiological measurements. Chapter 3 is a review of the recent advances made in the study of the development of functional connectivity in brain networks. This chapter covers some empirical evidence for the development of functional …

The Neural Representation Of Duration In Event Concepts, Christopher Todd Hackett

Theses and Dissertations

Little is known about the neural basis of temporal concepts. Some have suggested that temporal concepts are grounded in spatial or temporal processes. Here we aimed to examine the representation of duration of event concepts, and compare them with judgments of object size, which may entail spatial processing. A 2x2 block design used event and object nouns as stimuli that were presented during functional imaging. Participants made judgments about event duration, object size, and event and object valence. In addition to whole-brain analyses, we examined activations in areas known to be involved in temporal processing and spatial processing. Knowledge of …

Structural, Functional, And Behavioral Alterations To The Dopamine System In The Female Hiv-1 Transgenic Rat, Robert Francis Roscoe Jr.

Theses and Dissertations

HIV-associated cognitive disorders continue to affect approximately 25 million individuals worldwide, and its prevalence is expected to increase as the lifespan of HIV-1 infected individuals continues to improve. The HIV-1 transgenic rat expresses 7 of the 9 genes that encompass the virus, and is an appropriate model for studying chronic HIV-1 infection at a level that is controlled through combined antiretroviral therapy. Psychostimulant abuse is known to exacerbate HAND symptomology, but the psychostimulant methylphenidate is a first line of treatment for HIV associated cognitive inhibition. Dopamine transport abnormalities in the HIV-1 Tg rat have been well characterized through behavioral testing; …

Iv Prenatal Nicotine Exposure Modulates Α6, Α7, And Α4Β2 Nicotinic Acetylcholinergic Receptor Subunit Expression In Male And Female Neonatal And Adolescent Rat Offspring: An Autoradiographical Analysis, Amanda Morgan

Theses and Dissertations

Maternal smoke exposure produces long-term adverse cognitive and behavioral outcomes in offspring, including an increased likelihood of attention problems (e.g., attention deficit hyperactivity disorder; ADHD) and drug abuse. Preclinical research shows that gestational exposure to nicotine, the primary psychoactive compound in tobacco smoke, influences the neurodevelopment of attention and reward neuronal circuits. This study investigated hypotheses about five brain regions, to determine if prenatal nicotine (PN) exposure altered expression of nicotinic acetylcholine receptors (nAChRs). A low dose, intravenous nicotine (IV) exposure method was used to administer nicotine (0.05 mg/kg/injection) or saline, 3x/day on gestational days 8–21 (Treatment). Brain tissue was …

The Syntax-Space Effect, Timothy W. Boiteau

Theses and Dissertations

Previous research has linked the concept of number and other ordinal series to space via a spatially-oriented number line. Other researchers have shown that language as well may have an underlying spatial representation, though this seems to be tied to visual scene recognition and production and is potentially an idiosyncratic effect of a limited set of concrete verbs. In this dissertation, employing a novel method that measures the underlying spatial biases of actors in transitive sentences, I show that findings from previous studies showing a relationship between transitivity and space reflect an interaction between word order in the sentence, order …

Sleep Extension And Stable Sleep Schedules In Older Adults, Alexandria M. Reynolds

Theses and Dissertations

There is consistent evidence demonstrating a “U-shaped” association between sleep duration and mortality, as well as several morbidities, such as increased systemic inflammation, decreased cognitive performance, and mood disturbances. Much of the information on long sleep is epidemiological in nature. The present study examined the associations between sleep duration and extension on mood, inflammation, and cognition. Ten (50-79 y) healthy adults who report sleeping 6-8 h were assessed on cognitive, emotional, and inflammatory measures in a cross-over design. Following a baseline week, participants were randomized to one of two three-week treatments: (1) a control treatment of habitual time in bed; …

Representation Of Affect From Fmri Data As A Function Of Stimulus Modality And Judgment Task, Jongwan Kim

Theses and Dissertations

The theory of core affect posits that the neural system processes affective aspects of stimuli encountered by the organism quickly and automatically, resulting in a unified affective state described along the dimensions of valence and arousal. Core affect theory posits two functional subsystems that guide affective processing: a sensory integration and a visceramotor network. The proposed study investigates how the representation of affective dimensions depends on sensory modality, features of the task, and brain regions. A series of behavioral studies was run to develop an experimental stimulus set of silent videos and musical clips that met requirements of equating valence …