Life Sciences Commons^™

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 …

Characterizing Mekk1: Candidate Behavioural Isolation Gene, Caryn Dooner

Electronic Thesis and Dissertation Repository

Behavioural isolation can occur due to divergence in aspects of courtship and mating, and can contribute to reproductive isolation. The purpose of this study is to determine how a gene, Mekk1, contributes to female rejection behaviour between D. melanogaster and D. simulans. Unique polymorphisms were identified within D. simulans Mekk1 that could contribute to behaviour, most of which are non-coding. Both transcripts of Mekk1 appear to be expressed at similar levels in D. simulans and D. melanogaster. These data also indicate that Mekk1 may be expressed in a specific region of the brain called the mushroom body, …

The Neural Mechanisms Underlying The Perception And Production Of Learned Vocalizations In Songbirds, Shannon Katie Mischler

Electronic Thesis and Dissertation Repository

Songbirds produce a wide array of vocalizations, including song, and learned and innate calls. Songs and calls can be functionally defined. Songs are typically used to attract potential mates and defend one’s territory, whereas calls are used for everything else, such as advertising the presence of a predator, or location of a food source, and maintaining contact with members of one’s flock. The purpose of this thesis was to better understand the neural mechanisms underlying call production and perception in two songbird species; the black-capped chickadee (Poecile atricapillus) and the zebra finch (Taeniopygia guttata). My objectives …

Regulation Of The Amyloid Precursor Protein By Prostaglandin J2, A Mediator Of Inflammation: Relevance To Alzheimer’S Disease, Teneka L. Jean-Louis

Dissertations, Theses, and Capstone Projects

Inflammation plays a major role in Alzheimer’s disease (AD). Investigating how specific mediators of inflammation contribute to neurodegeneration in AD is crucial. Our studies focused on cyclooxygenases, which are key enzymes in inflammation and highly relevant to AD. Cyclooxygenases (COX -1, constitutive; COX-2, inducible) have emerged as important determinants of AD pathogenesis and progression. COX-2 is highly induced in AD, correlating with AD severity, and COX-1 is also involved in AD. Cyclooxygenases are the rate-limiting enzymes that convert arachidonic acid into prostaglandins (PGs), the principal mediators of CNS neuroinflammation.

The overall GOAL of these studies was to address the mechanisms …

The Role Of Glutamate Neurotransmission In The Ventral Tegmental Area In The Expression Of Conditioned Approach Learning, Priscila Hachimine-Merli

Dissertations, Theses, and Capstone Projects

Conditioned stimuli (CSs) come to function as CSs by acquiring the capacity to activate the same mesocorticolimbic dopamine (DA) neurons activated by primary rewards, producing conditioned activation of these neurons and their associated motivational states. This model stipulates that CSs activate mesocorticolimbic DA systems through the activation of glutamate receptors on DA neurons in the ventral tegmental area (VTA). We tested the hypothesis that glutamate receptor stimulation in the VTA is necessary for the expression of conditioned approach. Rats were tested in a conditioned approach protocol that consisted of 7 consecutive conditioning sessions (light presentations and food were paired), one …

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 …

Song Rhythm Development In Zebra Finches, Julia Hyland Bruno

Dissertations, Theses, and Capstone Projects

This dissertation investigates song-rhythm learning in songbirds. Songbirds have been studied extensively in mechanistic investigations into the sensorimotor underpinnings of the cultural transmission of learned vocalizations. While several studies identified forebrain song-system neurons that generate rhythmic song patterns, we know little about how song rhythms are learned. The first part of the dissertation describes methods for detecting and analyzing birdsong rhythm patterns, and demonstrates their utility for identifying the role of song rhythms in social interactions. Results suggest that rhythm plasticity in zebra finch song may provide a potential vehicle for communication. Controlled song-learning experiments further found that developing zebra …

Distribution And Activation Of Catecholaminergic Neurons In The Brain Of Male Plainfin Midshipman Fish: Divergence In Behavior And Reproductive Phenotype, Zachary Ghahramani

Dissertations, Theses, and Capstone Projects

The plainfin midshipman fish, Porichthys notatus, provides an excellent opportunity for delimiting the influence of neurochemical content on vertebrate vocal behavior, in part because the production and recognition of social-acoustic signals is vital to their reproductive behavior. There are two distinct reproductive male morphs that follow divergent developmental trajectories with corresponding alternative reproductive tactics: type I males are the territorial/nesting morph that vocally court females during the summer breeding season while type II males do not court females, but instead sneak spawn in competition with type I males. Catecholaminergic neurons, which synthesize and release the neurotransmitters dopamine or noradrenaline, …

Modulation Of Spasticity By Trans-Spinal Direct Current Stimulation In Animals With Spinal Cord Injury, Wagdy Mekhael

Dissertations, Theses, and Capstone Projects

Central nervous system injuries usually produce motor impairments that are exacerbated by pathologically altered muscle tone. Abnormal muscle tone interferes with voluntary movement and is associated with loss of dexterity. Prior work in our laboratory demonstrated that 30-second trans-spinal direct current (DC) stimulation can temporarily modify muscle tone in anesthetized spastic mice after spinal cord injury (SCI). These experiments described DC-induced muscle tone responses to be polarity-dependent. That is, anodal stimulation (current passed from the lumbar spine to sciatic nerve) decreased muscle tone, and cathodal stimulation (current passed from the sciatic nerve to the lumbar spine) increased it. The present …

Amelioration Of Prenatal Alcohol Effects By Environmental Enrichment In A Mouse Model Of Fasd, Aniruddho Chokroborty-Hoque

Electronic Thesis and Dissertation Repository

Maternal alcohol consumption during pregnancy results in a spectrum of behavioural and cognitive deficits collectively known as Fetal Alcohol Spectrum Disorders (FASD). Currently, little is know about if and how the external environment may modulate these deficits. I have used C57BL/6 mice to study this interaction between prenatal alcohol exposure and the postnatal environment. Alcohol exposure during synaptogenesis produces high levels of anxiety-like traits and decreased memory performance. Alcohol-exposed mice (and matched unexposed controls) were put in 'environmentally-enriched' conditions of voluntary exercise, physical activities and cognitive stimulation to ascertain the effects of a positive postnatal environment. The results show that …

The Effects Of Intranasal Orexin-A On Mk-801-Induced Attentional Deficits: Addressing Cognitive Impairment In An Nmda Receptor Hypofunction Model Of Schizophrenia, Eden Blake-Lea Maness

Dissertations, Theses, and Masters Projects

Schizophrenia (SZ) is a debilitating condition wherein those afflicted experience positive symptoms, including hallucinations and delusions, as well as negative symptoms, including alterations of processing affecting cognition and social interactions. The NMDA receptor hypofunction model of SZ asserts that a reduction in hippocampal NMDA receptor input produces the pathology of this disorder, promoting excessive frontocortical excitatory neurotransmission – particularly overstimulation of basal forebrain cholinergic neurons – that ultimately impairs cognitive and sensorimotor processes. Orexin-A (OxA), a neuropeptide principally involved in wakefulness and appetitive behaviors, has been shown to demonstrate cognitive-enhancing qualities in models of psychiatric and neurodegenerative illness. In the …

Early Life Immune And Physical Stress Directly Influences Anxiety-Like Behaviour In Adolescent Rats: Examining Sex Differences, Jordan M. Ward

Electronic Thesis and Dissertation Repository

This thesis examined the effects of neonatal acute immune activation with the endotoxin, lipopolysaccharide (LPS) on postnatal days 3 and 5 on adolescent anxiety-like behaviour in rats before and after a stress period. Previous research has shown that adults rats exposed to LPS during the neonatal stage show anxiety-like behaviour following a period of stress. This thesis investigated this effect in adolescence. The present results showed significantly higher anxiety-like behaviour in saline controls, and a potential neuroprotective effect of low dose LPS (15 µg/kg) contrary to what was reported in adult rats. As well, a phase of stressful, aversive conditioning …

Mechanisms Underlying Executive Function Deficits, Sagar Jayawantrao Desai

Electronic Thesis and Dissertation Repository

In our daily life, we come across situations where we meet unanticipated challenges, we must take certain decisions, pay attention, be flexible and inhibit impulsive actions to achieve goal directed behaviour. During these processes, we unknowingly use sets of interdependent cognitive processes collectively called ‘executive function’. Executive function is mainly regulated by the frontal lobe. Impaired executive function is associated with disorders such as schizophrenia, Alzheimer’s disease, autism and attention deficit hyperactivity disorder (ADHD).

In this thesis, we investigated neurotransmitters and interactions among them regulating executive function. Further, we investigated mechanisms underlying those interactions mediating executive function in rats using …

Prefrontal Cortex Dopamine Transmission Regulates Emotional Memory Processing And Morphine Reward Salience: Implications For Post-Traumatic Stress Disorder And Addiction Comorbidity, Jing Jing Li

Electronic Thesis and Dissertation Repository

Post-Traumatic Stress Disorder (PTSD) and addiction are strongly comorbid. However, the underlying neural mechanisms by which traumatic memory recall may increase addiction liability are poorly understood. The inability to suppress memory recall related to either stressful or rewarding, drug-related experiences may be an underlying neuropsychological feature capable of triggering both PTSD or addiction-related behaviours. Our previous research has shown that transmission through dopamine (DA) D₄ and D₁ receptor subtypes (D₄R, D₁R) within the prefrontal cortex (PFC) strongly modulates emotional memory acquisition and recall (Lauzon et al., 2009). Using olfactory fear conditioning and morphine conditioned …

Optogenetic Interrogation Of Primary Visual Cortex And Its Impact On Neural Coding And Behavior, Ariana R. Andrei

Dissertations & Theses (Open Access)

Understanding the mechanism by which the brain transforms simple sensory inputs into rich perceptual experiences is one of the great mysteries of systems neuroscience. Undoubtedly this involves the activity of large populations of interconnected neurons, but while the responses of individual neurons to a variety of sensory stimuli have been well-characterized, how populations of such neurons organize their activity to create our sensory perceptions is almost entirely unknown. To investigate this complex circuitry requires the ability to causally manipulate the activity of neural populations and monitor the resultant effects. Here we focus on primary visual cortex (V1), which has been …

Ephrin Receptors, Aiy Interneuron Physiology, And Behavior, Tyler Hill

Master of Science in Integrative Biology Theses

In order to survive, an organism must be able to receive, integrate, and respond to sensory stimuli. However, the cellular basis of sensory perception and response is difficult to study in complex animals such as humans, and is therefore poorly understood. The nematode Caenorhabditis elegans is a relatively simple organism yet displays many distinct behaviors, making it an ideal system to understand the relationship between gene function, cell shape, cell physiology, and behavioral output. Much of the thermosensory and chemosensory information that the nematode receives from its sensory neurons is processed via a pair of interneurons called AIYL and AIYR. …

Investigating The Role Of Cortical Inhibition In Tinnitus, Krystal Beh

Electronic Thesis and Dissertation Repository

Subjective tinnitus is characterized as the perception of a phantom sound with no external acoustic source, and is often described as a “ringing in the ears” sensation. While evidence supports a central origin for tinnitus, the underlying neural mechanisms for this condition remain elusive. The studies presented in this thesis offer significant contributions to understanding the neural basis of tinnitus by (1) validating a behavioural paradigm that can successfully screen rats for transient noise-induced tinnitus without any indications of false-positives, and (2) demonstrating that a local loss of inhibition is sufficient to induce gain enhancement in the primary auditory cortex, …

Cortico-Striatal Coordination Disrupted In Behaviorally Inflexible Moderate Prenatal Alcohol Exposed Mice, Kristin L. Marquardt

Biomedical Sciences ETDs

Up to 61% of adolescent school aged children with fetal alcohol spectrum disorder (FASD) have been suspended or expelled. Executive function deficits, like dis-inhibition and cognitive inflexibility, have been proposed to be better predictors of behavioral problems then IQ score, which qualifies these individuals for developmental disability and special school programs. Reversal learning, a widely used behavioral paradigm for assessing cognitive flexibility across species, has been shown to be impaired in rodent models of prenatal alcohol exposure (PAE). Here we show that a mouse model with daily maternal drinking, resulting in a BAC of 85 mg/dl throughout gestation, results in …

Examining The Neuronal Dopaminergic Pathway Underlying Sleep Behavior And Related Dopamine Sleep Disorders, Mary Beth Putz

Undergraduate Honors Theses

The human brain is an extremely complex organ with approximately 100 billion different neurons that are constantly sending and receiving messages. These messages are sent using the chemical messengers of the brain: neurotransmitters and neuromodulators. Mechanisms of neural control of sleep are substantially conserved across species. Evidence from multiple animal models including flies, zebrafish, and mice shows that the arousal, or wake phase, is regulated by conserved neuromodulators such as dopamine, norepinephrine, and serotonin. Since these neurotransmitter systems are distributed throughout the brain and sub-serve many functions in addition to sleep, the precise circuit mechanisms by which these neurotransmitters regulate …

Effects Of Sleep-Deprivation On Decision-Making And Action Selection, Shalin N. Shah

Undergraduate Honors Theses

This thesis addresses neuroscience research focusing on the brain’s mechanisms underlying behavioral choice, or prioritization, and decision-making. The research has been conducted with Drosophila melanogaster, the fruit fly – a good model from both the behavioral and neural perspectives. This project specifically observes the co-regulation of sleep with two other behaviors – courtship and oviposition. The overlap between the sleep and courtship circuits in the brain should provide a good model for behavioral prioritization, and the interaction between sleep and ovipositional preference should provide a model for understanding the effects of sleep on decision-making. All three of these adaptive behaviors …

Mindfulness And Law Enforcement: An Effective Approach To Implementing Mindfulness For First Responders, Gina White

Mindfulness Studies Theses

An increasing number of studies show that people employed as first responders in high trauma service jobs tend to experience a high level of stress, at work and after hours. Studies suggest that constant exposure to job related stress leads to both physical and mental dysregulation. This study looks at the effects of implementing mindfulness tools and techniques to those working in law enforcement. Other works on this topic report mindfulness as a successful tool to increase wellbeing to a broad spectrum of populations. The methodology used in this study was designed specifically for first responders. The data findings were …

An Analysis Of Neurogenesis In A Mouse Model Of Chemotherapy Related Cognitive Impairment, Maxwell A. Hennings

Electronic Theses and Dissertations

Cancer patients treated with adjuvant chemotherapy often experience cognitive decline following treatment. This phenomenon, often dubbed “chemo brain” or “chemo fog” is usually temporary, but for a subset of survivors, these cognitive impairments can be long-lasting (>10 years) and negatively affect patients’ quality of life, career performance, and social fulfillment. While it is unclear what neurobiological mechanisms underlie chemotherapy related cognitive impairment, the majority of the animal literature has focused on adult neurogenesis. One process important for neurogenesis is the proliferation of new neurons within the dentate gyrus of the hippocampus. It is evident that many chemotherapy agents can …

Therapy Dogs And The Impact On Employees In The Pediatric Medical Setting, Laine Foith

Electronic Theses and Dissertations

More than 40% of nurses reported experiencing significant burnout. Burnout is characterized by disengagement, cynicism, negative views of personal accomplishment and ability, and emotional exhaustion. The healthcare providers that experience burnout can possibly expect a decrease in ability to recognize/report errors, increase of negative feelings toward the patient, and decrease levels of patient satisfaction (Ernest, 2014). One of the ways Schub (2015) suggested to regulate burnout for employees was to provide psychosocial support to colleagues to reduce stress. This study is one of the first attempts to bridge the gap between the unknown correlation between qualitative and quantitative benefits of …

Rat Hind Limb Nociceptive Withdrawal Response To Heat And Mechanical Stimuli Depends On Initial Position Of The Paw But Not Stimulus Location, Giavanna Verdi

Senior Honors Projects, 2010-2019

Mammals rapidly withdraw their hind limb in response to noxious stimulation, which is a protective movement known as the nociceptive withdrawal response (NWR). The NWR has been previously studied in spinalized, decerebrated and anesthetized non-human and human mammals; however, there is minimal information on the NWR in intact, unanesthetized non-human mammals.

The first specific aim was to identify the factors that determine the direction and magnitude of the NWR in intact, unanesthetized rats. Based on previous studies, we hypothesized that the location of stimulation and the initial position of the paw preceding the NWR will influence the direction and magnitude …

The Effects Of Ocular Dominance On Visual Processing In College Students, William A. Holland

Senior Honors Projects, 2010-2019

V. Abstract

The role of ocular dominance in processing visual memory and analytic tasks is unknown. Previous research variably showed both significant effects and no effect of ocular dominance on visual perception, motor control and sports performance. Consequently, the goal of this study was to determine if there is a relationship between ocular dominance and visual processing under a variety of computer gaming tasks. This was accomplished by first determining subjects’ ocular dominance through the use of the Miles test, and then proceeding to examine the subjects’ visual performance on four different Lumosity games under three conditions: left eye, right …

Mouth Exposure To Carbohydrate Prior To Exercise Possibly Impairs The Efficacy Of Carbohydrate Mouth Rinsing During Exercise, Kevin Decker

Masters Theses, 2010-2019

Decker K. P., M. J. Saunders, N. D. Luden, C. J. Womack, and N. J. Hladick. Mouth Exposure to Carbohydrate Prior to Exercise Possibly Impairs the Efficacy of Carbohydrate Mouth Rinsing during Exercise. Purpose: Carbohydrate mouth-rinsing (CHO-MR) during intense endurance exercise has been associated with improved cycling performance, due to neurological influences. However, prior studies have reported the efficacy of CHO-MR is attenuated following a pre-exercise meal. To determine if this outcome is related to desensitization of CHO receptors (rather than metabolic effects following digestion), this study will investigate whether CHO-MR prior to exercise influences cycling performance when CHO-MR …

Central Role Of Vasotocin In The Neuroendocrine Regulation Of Stress Responses And Food Intake In Chickens, Gallus Gallus, Gurueswar Nagarajan

Graduate Theses and Dissertations

It is well known that arginine vasotocin (AVT) in birds is involved in physiological homeostasis such as cardiovascular, osmotic regulation as well as reproductive functions. Pertinent to these physiological functions, AVT immunoreactive (-ir) neurons in the hypothalamus have been found associated with hemorrhage, dehydration, oviposition and other physiological regulation. Evidence, however, suggests that AVT also plays significant roles in modulating behavior, memory, stress, and food intake. This dissertation research addresses the latter two neuroendocrine functions of AVT in detail within the chicken brain. First, the functional role of AVT-ir neurons in conjunction with corticotropin releasing hormone (CRH)-ir neurons in the …

On The Origin Of Sensory Errors, Jonathan R. Flynn

Dissertations & Theses (Open Access)

Estimation of perceptual variables is imprecise and prone to errors. Although the properties of these perceptual errors are well characterized, the physiological basis for these errors is unknown. One previously proposed explanation for these errors is the trial-by-trial variability of the responses of sensory neurons that encode the percept. Initially, it would seem that a complicated electrophysiological experiment would need to be performed to test this hypothesis. However, using a strong theoretical framework, I demonstrate that it is possible to determine statistical characteristics of the physiological mechanism responsible for perceptual errors solely from a behavioral experiment. The basis for this …

Anxiety-Like Behaviors And C-Fos Expression In Adult Zebrafish: Effects Of Housing Conditions, Alcohol And Caffeine, Adam Douglas Collier

Dissertations

Alcohol abuse is the third largest risk factor for disease world, responsible for an estimated 3.3 million deaths each year. The concomitant ingestion of alcohol and caffeine is hypothesized to increase risk factors associated with alcohol use alone by reducing subjective effects of intoxication. The zebrafish (Danio rerio) has recently garnered attention from researchers as an effective pre-clinical in-vivo animal model in behavioral pharmacology research, largely due to small size, low-cost and ease of drug delivery. A number of studies have reported the effects of alcohol and caffeine on zebrafish behavior at a variety of doses. However, the …

Persistent Neurobehavioral Traits In A Mouse Model Of Prenatal Ethanol Exposure, Jill M. Lawrence

Neuroscience Honors Papers

Fetal Alcohol Spectrum Disorders (FASD) effect an estimated 2% of the population, causing a range of symptoms: from craniofacial defects to inhibited cortical growth (May, et al., 2009; Murawski, et al., 2015). Impaired medial forebrain function apparent in FASD is associated with lifelong cognitive behavioral deficits, but these consequences may be avoided with early diagnosis and intervention (Streissguth, et al., 2004). Our goal is to identify early neurobehavioral abnormalities that persist into adulthood that could potentially serve as early indicators for FASD. Mouse models of prenatal ethanol exposure were developed using a voluntary drinking paradigm that introduced a sweetened ethanol …