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Variation In Sign-Tracking And Goal-Tracking Behaviors In A Genetically Diverse Inbred Panel Of Mice, Emily A. Schoenblum

Undergraduate Honors Theses

No abstract provided.

Contributions Of Reward Identity And Time Prediction Errors To Pavlovian Learning, Daniel B. Siegel

Dissertations, Theses, and Capstone Projects

Some models of associative learning attempt to explain effects such as blocking and unblocking as reflecting a prediction error (PE): Associative strength, and thereby learning, are said to be greater when the unconditioned stimulus (US) received following a cue deviates from one’s expectations. Some models of PE-motivated behavior and PE-relevant brain activity represent the US as a single quantitative variable for outcome value, and that learning therefore only occurs when outcome value differs from expectations. There is growing evidence to suggest that changes in other dimensions of reward, such as identity and timing, also contribute to learning. In Experiment 1, …

Identifying Neuron Clusters Controlling Movement Vigor, Jay A. Strabinick

Cal Poly Humboldt theses and projects

Parkinson’s disease (PD) is a neurodegenerative disease that progressively decreases dopaminergic function. Lower amounts of dopamine may cause an innate motivational shift that decreases movement vigor when performing difficult tasks. In PD patients, bradykinesia, the slowing of movement, is characteristic of this decrease in vigor. The movement vigor hypothesis proposes that dopamine neurons modulate performance aspects of movement, like speed and persistence. This paper proposes a series experiments utilizing neuron recording techniques in zebrafish that would test the movement vigor hypothesis by determining whether in fact there is a distinct group of dopamine neurons that modulate movement vigor. Core elements …

Behavioral, Endocrine, And Neural Responses To Stress In Postpartum And Nulliparous Rats : Potential Mechanisms Of Postpartum Stress Resilience, Joanna Medina

Legacy Theses & Dissertations (2009 - 2024)

Major depressive disorder is one of the most pervasive psychiatric illnesses in the United States. Women are at greater risk for developing depression, particularly during their childbearing years. Approximately 17% of new mothers develop postpartum depression within 4 weeks after parturition. The risk for postpartum depression is even greater in women who do not breastfeed or stop breastfeeding early. Major depressive disorder and postpartum depression share the same symptomology and common etiological bases. Dysregulated stress responses, dopamine activity, and neuroinflammation are recognized mechanisms for depression. The transition to motherhood encompasses physiological and behavioral adaptations in the brain essential for ensuring …

Decipher The Effect Of Gamification In Harnessing Boredom And Improving Performance, Zhuoyi Zhao

Theses and Dissertations (Comprehensive)

My thesis investigates the effectiveness of gamification in harnessing boredom and improving performance in a repetitive work process. In video games, “loot” rewards are unpredictable, intermittent gains used to motivate players to repeat boring actions. In a 2 X 2 experiment, I examine how loot rewards in point form may impact 1) disengagement, which is an immediate outcome of boredom, and 2) performance in settings where the points have and do not have cash value, respectively. More specifically, I manipulate the level of point reward unpredictability (fixed versus loot) and whether point rewards have cash value (absent versus present).

In …

Assessment Of Dopaminergic And Serotonergic Receptor Antagonists In Male Rats Trained To Discriminate 4-Methylmethcathinone (Mephedrone), Rachel L. Burroughs

Masters Theses

Preclinical drug discrimination studies of the synthetic cathinone, 4-methylmethcathinone (mephedrone) have demonstrated its effects are comparable to those of other popular psychostimulant drugs. Few studies have directly examined the contribution of specific neurotransmitter receptors to mephedrone’s discriminative stimulus effects. The present study investigated the role of dopamine and serotonin receptors in these effects. Eight adult male Sprague-Dawley rats were trained to discriminate 3.0 mg/kg mephedrone from saline. After dose-response curves were determined with mephedrone (0.375-3.0 mg/kg), a series of stimulus antagonism tests were conducted with dopamine antagonists (Sch 23390, haloperidol) and serotonin antagonists (WAY 100,635, MDL 100,907, pirenperone) administered as …

The Impact Of Levodopa Administration On Learning From Short-Term And Long-Term Action Consequences: A Paradigm Validation., Masood Rezaei

Electronic Thesis and Dissertation Repository

Behavioral and neuroimaging studies have identified two valuation systems in the human brain for controlling behavior known as model-free (MF) and model-based (MB). MF is based on immediate evaluation and MB is based on long-term evaluation of the outcome of our decisions. Previous studies suggest that dopamine baseline activity may play an important role in the balance between the two systems and determine how they compete or interact in controlling our actions. The overarching aims of this study is to investigate the impact of levodopa administration on learning from immediate and long-term action consequences, and to dissociate the role of …

The Role Of Dopamine In Decision Making Processes In Drosophila Melanogaster, Michelle C. Bowers

Undergraduate Honors Theses

Understanding the neural processes that mediate decision making is a relatively new field of investigation in the scientific community. With the ultimate goal of understanding how humans decide between one path and another, simpler models such as Drosophila Melanogaster, the common fruit fly, are often utilized as a way of determining the neural circuits involved in these decision-making processes. One of the most important decisions flies make is the decision of where to lay their eggs (oviposit). Choosing the proper substrate upon which to lay eggs is a crucial decision that can ultimately impact their fecundity. This paper investigates the …

Murine Genetic Variance In Sugar And Fat-Conditioned Flavor Preferences: Roles Of Dopamine, Opioid And Nmda Receptors And Nutritive Sensing, Tamar T. Kraft

Dissertations, Theses, and Capstone Projects

As obesity and diabetes have emerged as a severe public health crisis, understanding the mechanisms underlying the consumption of sugars and fats has become a topic of vigorous study. From a biological standpoint, genetic dispositions, neurochemical and hormonal influences, and predetermined orosensory and postingestive signals that modulate the hunger and satiety process may govern physiological aspects of the obesity puzzle. In addition to an innate appetite and attraction for simple carbohydrates and fats, learning plays an important role in modulating preferences for sugar- and fat-rich foods in rodents, including inbred mouse strains. Marked genetic variance has been observed among murine …

Structure And Function Of Dopamine In The Inner Ear And Auditory Efferent System Of A Vocal Fish, Jonathan T. Perelmuter

Dissertations, Theses, and Capstone Projects

The neuromodulator dopamine is considered essential for coordinating the internal motivational state of an organism with appropriate behavioral responses to stimuli in the external environment. This could be accomplished by modifying the function of neural circuits involved in sensory processing such that they are “tuned in” and optimally sensitive to important stimuli during critical time windows. While dopamine modulation of auditory processing has been studied in the central nervous system, neuromodulation can also occur outside the brain, in the inner ear. The majority of investigations of dopamine in the ear are conducted using rodents and focus on its role in …

The Effect Of Dopamine Blockade On Sensorimotor Gating In Social Phenotypes Of The African Cichlid Fish Astatotilapia Burtoni, Raymond A. Turco

Theses and Dissertations

We asked if blocking dopamine could improve implicit sensory gating deficits in a socially-defeated fish of a naturally-agonistic species. This study investigated the effects of dopamine D2R receptor antagonist metoclopramide on sensorimotor gating using a prepulse inhibition (PPI) paradigm in social phenotypes of male A. burtoni African cichlid fish.

Naloxone And Ethanol Addiction Reinforcement, Roland T. Smith Iii

Theses and Dissertations

A study was carried out examining how naloxone administered after high-incentive ethanol exposure can interrupt the reinforcing effect of drugs of abuse in C57BL/6 mice. Naloxone was shown to be an effective tool for blunting preferential and motivational behaviors associated with ethanol addiction.

When Brain Stimulation Backfires, Sarah Beth Bell

Theses and Dissertations--Psychology

tDCS brain stimulation does not always work in the intended direction. It has been found to sometimes worsen behavior rather than improve it. A preliminary study shows that people high on sensation-seeking and lack of premeditation were prone to reverse effects of tDCS on performance on a Stop Signal Task. Both of these constructs are related to dopamine levels. Study 2 seeks to intentionally cause a reverse effect of tDCS by increasing participants’ dopamine levels via caffeine. There was not a significant interaction between tDCS and caffeine on errors on the Stop Signal Task in this study. However, other factors …

Examining The Associative Learning And Accumbal Dopaminergic Mechanisms Of Caffeine Reinforcement, Curtis Bradley

Electronic Theses and Dissertations

Caffeine is the most consumed psychoactive substance in the world, and most caffeine consumption in coffee and energy drinks is intended to produce a psychoactive effect. However, caffeine is not a primary reinforcer in preclinical paradigms – non-human species do not reliably take the drug to produce a psychoactive effect. However, caffeine is a ‘reinforcement enhancer’ in preclinical models; the effects of caffeine increase the motivation to obtain other non-drug reinforcers. The overall goal of this project was to determine if these reinforcement enhancing effects of caffeine could promote caffeine self-administration and to subsequently investigate the behavioral and neurochemical underpinnings …

Effort-Related Motivational Dysfunctions: Behavioral And Neurochemical Studies Of The Wistar-Kyoto Rat Model Of Depression, Brendan Abbott

Masters Theses

Depression and related disorders are characterized by motivational dysfunctions, including deficits in behavioral activation and exertion of effort. Animal models of relevance to depression represent a critical starting point in elucidating the neurobiological mechanisms underlying motivational dysfunctions. The present study explored the use of the Wistar-Kyoto (WKY) animal model of depression to examine effort-related functions as measured by voluntary wheel running and performance on a mixed fixed ratio 5/progressive ratio (FR5/PR) operant task. Given the known link between activational aspects of motivation and the mesocorticolimbic dopamine (DA) system, the behavioral effects of d-amphetamine (0.5 and 1.0 mg/kg, IP), a psychostimulant …

Effects Of Chemogenetic Inhibition Of Dopamine Transporter- Or A2a-Expressing Neurons On Spontaneous Activity And Motivation To Consume A Palatable Food Reward, James D. Wherry

Graduate Dissertations and Theses

Dopamine (DA) transmission in the striatum influences the motivated pursuit of rewarding stimuli. Pharmacological and opto- and chemo-genetic studies have suggested that the release of DA onto D2+/A2A+-expressing striatopallidal neurons, plays a role in this process. To determine the potentially dissociable roles of DA-releasing ventral midbrain and striatopallidal neurons on motivational processes, we employed double transgenic mice that expressed inhibitory DREADDs—designer receptors that are activated only by otherwise inert ligands—only in dopamine transporter (DAT) or A2A adenosine receptor (A2A) expressing neurons, allowing us to transiently inhibit either DA-releasing neurons (DATcre/DREADD) or striatopallidal neurons (A2Acre/DREADD) during various tests. In the first …

Possible Breakdown Of Dopamine Receptor Synergism In A Mouse Model Of Huntington's Disease, Samantha F. Kennedy

University of New Orleans Theses and Dissertations

The model of basal ganglia function proposed by Albin, Young and Penney (1989) describes two anatomically independent motor pathways, the direct and indirect. However, under normal conditions striatal dopamine (DA) is required for the expression of motor behavior, and DAergic control of the two pathways (via D1 and D2 receptors, respectively) is dependent on co-activation. We tested for a possible breakdown of D1/D2 synergism using transgenic R6/1 mice bearing the human huntingtin allele (Htt). Motor stereotypy, observed prior to the onset of HD-related symptoms, was rated on a 5-point scale following activation of: A) D1 receptors alone, B) D2 receptors …

The Nucleus Accumbens Core Dopamine D1 And Glutamate Ampa/Nmda Receptors Play A Transient Role In The Performance Of Pavlovian Approach Behavior, Veronica Dobrovitsky

Dissertations, Theses, and Capstone Projects

The role of the nucleus accumbens core (NAc core) continues to be redefined with newly acquired data on neurochemical mechanisms mediating the learning and performance of behavior. Previous empirical data showed that dopamine transmission at the D1 receptor (D1R) plays a transient role in the expression of learned Pavlovian approach behavior. Here we show that, prior to overtraining, dopamine activity at D1Rs specifically within the NAc core is critical for the performance of approach behavior elicited by the recently-acquired reward-paired cue. Blockade of D1Rs in the NAc core, but not the dorsomedial striatum or NAc shell, disrupted approach responses during …

Cannabis Use Frequency And Mood On Creativity, Caitlin Clark

Cal Poly Humboldt theses and projects

This study examines the relationship between cannabis use (infrequent, moderate, and heavy use) and one’s mood (neutral, positive, and negative) on creativity. Folk ideas of creativity and the relationships between cannabis use and mood may not reflect the real relationship between these factors (e.g. regarding cannabis use, it is perceived to be linked with higher rates of creativity; regarding mood, negative states [i.e. tortured artist] are thought to fuel creativity). Although both cannabis use and mood have been found to influence creativity independently, the current study is unique in its aims to identify whether cannabis use and mood interact to …

Are Caffeine’S Effects On Neuronal Calcium Levels Due To The Caffeine Metabolite, Paraxanthine?, Kendra Jean Hartsuyker

Cal Poly Humboldt theses and projects

Caffeine has diverse effects on neurons including, potentially, protection against Parkinson’s-related neurodegeneration. Caffeine may protect neurons from damage by limiting mitochondrial membrane permeability through a calcium-dependent mechanism. This study was a first step investigating calcium’s role in caffeine neuroprotection in vivo using zebrafish larvae. Elavl3:GCaMP6s zebrafish, which express a genetically encoded fluorescent calcium indicator protein in most CNS neurons, received caffeine (0, 50, 125, 250 µM, bath applied) in an ascending dose series during fluorescence calcium imaging of a central catecholaminergic nucleus (a proposed zebrafish homolog of the locus coeruleus, a structure affected in Parkinson’s disease). Parallel experiments tested effects …

Dopamine D1 Receptor Activity In The Basolateral Amygdala Is Important For Mediating Fear, Reward And Safety Discrimination Learning, Ka Ho Ng

Open Access Theses

Post traumatic stress disorder (PTSD) patients frequently show impairment in safety learning (Jovanovic, Kazama, Bachevalier, & Davis, 2012). Since the amygdala is known to be critical for emotional processing(Wassum & Izquierdo, 2015) and dopamine signaling in the amygdala is important for mediating both fear and reward learning, current experiments examined the role of dopamine signaling in the BLA in mediating both safety learning and reward seeking. We manipulated dopamine D1 receptor activity with a D1 receptor agonist (SKF 38393) or D1 receptor antagonist (SCH23390) either systemically or infused directly into the BLA 20 minutes prior to training rats in a …

Effects Of Optogenetic Activation And Pharmacological Modulation Of Dopamine Neurons, Remington J. Rice

All NMU Master's Theses

This study explored the use of optogenetic tools to better understand treatments used for schizophrenia. The “positive” symptoms (e.g., hallucinations, paranoia, etc.) of schizophrenia may come from overexpression of dopamine in mesolimbic dopamine neurons. Positive symptoms can be produced in healthy volunteers treated with amphetamine, a psychostimulant drug and dopamine releaser. Conversely, antipsychotic drugs may reduce positive symptoms by blocking dopamine receptors. This study used optogenetics to explore how drugs that alter neurotransmission, might alter behaviors occurring from activation of mesolimbic dopamine (DA) neurons in the ventral tegmental area (VTA). Light-induced activation of DA neurons in the VTA in male …

Cocaine-Induced Behavioral Sensitization And Conditioned Place Preference In Japanese Quail (Coturnix Japonica): A Focus On Sex Differences And Dopaminergic Mechanisms, Karin E. Gill

Theses and Dissertations--Psychology

Research has indicated that gonadal hormones may mediate behavioral and biological responses to cocaine. Estrogen, in particular, has been shown to increase behavioral responding to cocaine in female rats relative to male rats. The use of Japanese quail may add to our knowledge of sex differences in drug abuse because of their advanced visual system and the ability to control their gonadal hormones via alterations in photoperiod. In three experiments, cocaine-induced behaviors were examined using this avian model.

In Experiment 1, I investigated the potential sex differences in cocaine-induced locomotor activity between male and female Japanese quail and I examined …

Individual Differences In The Dopaminergic Reward System: The Effect Of Genetic Risk On Neural Reward Sensitivity And Risky Choice, Heather E. Soder

USF Tampa Graduate Theses and Dissertations

When making decisions, individuals evaluate several possible outcomes of their choice; however, some display heightened reward sensitivity, despite the potential for future negative consequences, which can lead one to make risky choices. Rewards are processed in the mesolimbic dopamine reward system, and this system is in part modulated by genetic polymorphisms that are associated with dopamine transmission. The current study tested if genetic polymorphisms that are associated with enhanced dopamine neurotransmission will be more neurally reward sensitive, score higher on self-reported impulsivity, and make riskier choices. In a sample of 85 participants, five genetic polymorphisms were genotyped and used to …

Genetic Moderation Of Phenotypic And Neural Indicators Of Peer Influenced Risk-Taking Behavior: An Experimental Investigation, Troy Alan Webber

USF Tampa Graduate Theses and Dissertations

Risk-taking behavior (RTB) is defined as behavior involving the probability of reward with concurrent probability of some negative outcome. Peer influence is among the most robust predictors of RTB, such that greater peer influence, particularly deviant or delinquent peer influence, is associated with increased RTB. Evidence suggests that those with genetic predispositions for RTB may also be more susceptible to peer influence as a function of genotype. Given that genetic polymorphisms within the dopaminergic system have evidenced associations with various forms of RTB and delinquent peer affiliation, it is possible that these genes may interact with peer influence to predict …

The Influence Of Dopamine On The Magnitude And Duration Of The Placebo Effect, Steve T. Brewer

University of New Orleans Theses and Dissertations

A placebo effect is a real and beneficial psychobiological phenomenon following the administration of a substance or procedure that has no inherent power to produce an effect. Nocebo effects, on the other hand are genuine and detrimental psychobiological phenomenon following the administration of and inert substance or procedure. These effects have been extensively studied but are not well understood. Central to the development of a placebo effect is the anticipation of benefit or the anticipation of harm. Indeed, expectancy and conditioning are thought to be the two primary mechanisms involved in the acquisition of the placebo effect. The neurotransmitter Dopamine …

The Neurobehavioral Consequences Of Gestational And Chronic Atrazine Exposure In Male And Female Sprague Dawley Rats, Jennifer L. Walters

Dissertations

The adverse health risks of exposure to the herbicide, atrazine, in humans are not fully understood. Although numerous studies have demonstrated atrazine to be an endocrine disrupter, the neurobehavioral consequences of atrazine exposure have not been thoroughly examined. The aim of this study was to investigate the effects of environmentally-relevant levels

of gestational followed by continued chronic atrazine exposure on motor function, learning and memory, anxiety, and striatal dopamine content in rodents. Pregnant Sprague Dawley rats were treated by gavage with 100 µg/kg atrazine (ATZ low), 10 me/kg atrazine (ATZ high), or vehicle on

gestational day l through postnatal day …

Associations Between Hypothalamic-Pituitary-Adrenal Axis System Gene Variants And Cortisol Reactivity In Preschoolers: Main Effects And Gene-Environment Interactions, Haroon I. Sheikh

Electronic Thesis and Dissertation Repository

Exposure to stressful events during early development has consistently been shown to produce long lasting effects on the hypothalamic-pituitary-adrenal (HPA) axis, which may increase vulnerability to mood and anxiety disorders. Recently reported genetic association studies indicate that these disorders may be influenced, in part, by gene-environment interactions (GxE) involving polymorphisms within the corticotrophin-releasing hormone and monoaminergic system genes. However, little is known about how genetic variants and life stress work to shape children’s neuroendocrine reactivity and emerging symptoms. Therefore, the aim of this thesis is to examine main effects of candidate genes and GxE on the neuroendocrine stress response and …

The Effect Of Gaba A Antagonism On Locomotor Activity And Dopamine Release In The Mouse Caudate Putamen Following Acute Toluene Inhalation: An In-Vivo Microdialysis Study, Sean Callan

Wayne State University Theses

Toluene is ubiquitous solvent commonly inhaled recreationally. Despite its frequency of misuse, there is little understanding of how toluene acts within the brain. To examine this, this master's thesis examined the impact of acutely inhaled toluene on dopamine (DA) release in the mouse CPu in vivo using microdialysis techniques. Toluene inhalation produced dose-dependent increases in DA levels as well as changes in locomotor activity. These effects were potentiated by pre-treatment with the GABAA antagonist bicuculline via reverse microdialysis delivery. These results suggest that the DA dynamics of toluene abuse are related to toluene's previously explored effects on the GABA system. …

Contribution Of Nucleus Accumbens Core To Impulsive Choice: Role Of Dopamine And Glutamate Systems, Justin R. Yates

Theses and Dissertations--Psychology

Impulsive choice refers to the inability to delay gratification and is associated with increased drug abuse vulnerability. Understanding the underlying neural mechanisms linking impulsive choice and drug abuse can contribute to improved treatment options for individuals with substance use disorders. Evidence suggests a major role for nucleus accumbens core (NAcc) in impulsive choice and the reinforcing effects of drugs of abuse. The neurotransmitters glutamate (Glu) and dopamine (DA) are implicated in the neural adaptations observed in drug addiction; however, the role of intra-NAcc Glu and DA in impulsive choice is unclear. Rats were trained in a delay discounting task, in …