Neuroscience and Neurobiology Commons^™

Behavioral Ecology Of A Desert Ambush Predator: Assessing Movement Patterns, Habitat And Microhabitat Use, And The Innate Feeding Response Of Eastern Black-Tailed Rattlesnakes (Crotalus Ornatus) In The Northern Chihuahuan Desert, James Emerson

Open Access Theses & Dissertations

Research on the ecology and evolution of rattlesnakes has been sporadic over the past 80 years, but has seen recent expansion into the diverse fields of physiology, physiological ecology, life history, behavioral ecology, ethology, reproductive biology, chemical ecology, venom biochemistry and medicine, conservation, and many other subdisciplines. The development of small, implantable VHF radiotransmitters in the 1980s revolutionized research in the field of behavioral ecology for rattlesnakes, which are uniquely suited for radiotelemetry studies because they possess several morphological, physiological, and behavioral characteristics that are unique among terrestrial vertebrates. The widespread application of radiotelemetry by the mid-1980s advanced the model …

Insights Into The Structure, Pharmacology, And Evolution Of The Glycine Transporter 2, Ashley Bryan Lopez

Open Access Theses & Dissertations

The balance between neuronal excitation and inhibition in the central nervous system is vital for survival. Overexcitation can be toxic and lead to certain manias or even death. On the other hand, extremely low levels of inhibition cause hyperekplexia, pain, and even forms of autism. Neuronal inhibition is, for the most part, achieved by two neurotransmitters, GABA and glycine. Levels of both neurotransmitters in the synaptic cleft are meticulously regulated by the GABA and glycine transporters, respectively, which belong to the solute carrier 6 (SLC6) family of neurotransmitter transporters and share structural similarities with other family members. In Chapter 1, …

Ketamine Pre-Exposure Does Not Influence Later-Life Responses To Reward-Related Stimuli In Female C57bl/6 Mice, Israel Garcia

Open Access Theses & Dissertations

Preclinical work indicates that exposure to traditional antidepressant medications, in adolescent and adult female subjects, alters reward-related behavior later in life. In recent years, the anesthetic ketamine (KET), now used as a fast-acting antidepressant, has shown promising therapeutic efficacy for the management of depression. However, the potential long-term behavioral consequences of KET exposure across development have not been thoroughly assessed. Thus, to address this issue, we examined if KET exposure, during adolescence or early adulthood, results in enduring alterations in responsivity to the rewarding properties of sucrose and cocaine later in life. Specifically, female C57BL/6 mice were randomly assigned to …

An Analysis And Representation In An Atlas Reference Space Of Putative Appositions From Neurons Expressing Alpha-Melanocyte-Stimulating Hormone With Neurons Expressing Hypocretin/Orexin Or Melanin-Concentrating Hormone, Vanessa Inez Navarro

Open Access Theses & Dissertations

The hypothalamus is a brain structure at the center of a variety of regulatory functions that have been explored by scientists and clinicians for almost a century. Among these functions, metabolic regulation and the control of appetitive behaviors have been fields of intensive research. Some of the major neural substrates involved in the hypothalamic control of feeding and the regulation of metabolic state include neuronal populations that express the neuropeptides alpha-melanocyte stimulating hormone (αMSH), melanin-concentrating hormone (MCH) and hypocretin/orexin (H/O). αMSH has been characterized in part as an anorexigenic peptide, while MCH and H/O have been characterized as having orexigenic …

Distributions Of Axons Immunoreactive For Alpha-Melanocyte Stimulating Hormone And Neurons Immunoreactive For Neuronal Nitric Oxide Synthase In The Hypothalamus Of The Adult Male Rat: An Analysis Of Interactions And Their Representation In An Atlas Reference Space, Eduardo Peru

Open Access Theses & Dissertations

In the present study, we have provided two sets of high spatial-resolution maps for neuronal populations containing the immunoreactive presence of the key feeding-related peptides hypocretin/orexin (H/O), alpha-melanocyte stimulating hormone (αMSH) and the nitric oxide-producing enzyme, neuronal nitric oxide synthase (nNOS). These were mapped across the mediolateral and dorsoventral extents of the hypothalamus in the Swanson rat brain atlas, from levels 23–30. The first set of these maps are of the chemoarchitectural distributions for each of the neuronal populations mentioned, which are novel in two ways. First, they were generated across multiple animals to serve as the basis for probability …

Inhibition Of Glycine Transporter 2: An Emerging Target For Chronic Pain, Elvia Lilia Padilla

Open Access Theses & Dissertations

Chronic pain is a complicated, completely unknown condition that has been studied based on its severe impact on the population. According to the American Academy of Pain Medicine, 1.5 billion people suffer from tension-type headaches, one of the most common symptomatic chronic conditions. Christopher L. Cioffi, 2019; mentioned approximately in US 116 million adults are explicitly afflicted by chronic pain. Chronic pain is described as dysfunction in nerves that have been continuous during a long period (Mills, 2019). Treatments for chronic pain are different types of common analgesics that relieve the pain for short periods such as aspirin, ibuprofen, paracetamol, …

Sex Differences In The Mechanisms That Modulate The Neurochemical Effects Of Nicotine, Kevin Uribe

Open Access Theses & Dissertations

Prior behavioral studies in our laboratory revealed that overexpression of the stress peptide, corticotrophin-releasing factor (CRF), in the mesocorticolimbic reward pathway enhanced the reinforcing effects of nicotine. The latter effect was greater in female versus male rats, suggesting that females are uniquely susceptible to the effects of stress on nicotine reinforcement. The goal of this dissertation was to examine the neurochemical mechanisms by which overexpression of CRF in the nucleus accumbens (NAc), a terminal region of the mesocorticolimbic pathway, modulates the behavioral effects of nicotine. Specifically, we examined whether nicotine-induced dopamine levels are altered by CRF overexpression via excitatory (glutamate) …

Molecular Mechanism Of Neurodegeneration Induced By 4-Nonylphenol, Michelle Alejandra Aranda

Open Access Theses & Dissertations

Neurodegeneration, a progressive loss of nerve cells, occurs in many neurological disorders, including Alzheimer's disease (AD) and Parkinson's diseases (PD), as well as in dementia. The pathogenesis of these diseases is unknown, and recent evidence suggests that environmental factors, which act as endocrine-disrupting compounds (EDCs) could play a significant role in developing the disease process. 4-Nonylphenol (4-NP), an EDC, and a ubiquitous environmental toxin has been shown to affect brain development and may cause neurodegeneration. 4-NP is produced in large quantities in the U.S. and used as raw materials for making detergents, pesticides, plastics, paints, cosmetics, rubber, and other industrial/household …

Shining Light On An Amygdala -- Brainstem Connection Important For Attention Processing, Jose Carlos Cano

Open Access Theses & Dissertations

We are continuously being exposed to an exorbitant amount of sensory information, which should result overwhelming. However, the nervous system operates several intrinsic sensory filtering mechanisms that allow us to cope with such sensory cluttering and shape appropriate behavior. Sensorimotor gating is a pre-attentive neuronal filtering mechanism that gates superfluous sensory information, and orients attentional resources towards salient information processing. Its relevance becomes in individuals suffering from schizophrenia and several otherwise unrelated neuropsychiatric disorders where sensorimotor gating is impaired. To understand the neural impaired mechanisms, extensive research studies have focused on first identifying the neural substrates underlying sensorimotor gating. This …

Identification Of The Cell Type Expressing The Glycine Transporter 1 (Glyt1) In The Thalamus, Patricia A. Lozano

Open Access Theses & Dissertations

Glycine acts as an inhibitory neurotransmitter and a co-agonist of NMDAR at the glutamatergic synapses. Termination of glycinergic neurotransmission is achieved by glycine transporter 1 (GlyT1) and glycine transporter (GlyT2). Both transporters are expressed in the spinal cord, brainstem and cerebellum, but GlyT1 is also expressed in the retina and the forebrain. Previous studies have described the role and cyto- architecture of GlyT1 in the caudal areas of the brain and retina, but not in the structures of the forebrain. Based on our preliminary data, GlyT1 is highly expressed in the thalamus, an area involved in sensory and motor signal …

U.S. Perceptions Of Economic Mobility Since The Enactment Of Nafta And Their Impact On American Politics And Society, Jairemy Quinton Edwards

Open Access Theses & Dissertations

In this study, I examine how perceptions of NAFTA developed over 20 years since its enactment, measured as perceived economic mobility in 2016, have affected more recent public perceptions leading to increased, controversial tendencies towards nationalism, protectionism, and pessimism about the future of the U.S. economy. I then assess whether and how such perceptions in turn may have affected voter perceptions about Donald Trump, setting the stage for his 2016 election victory. Therein, I have found that among U.S. voters in 2016, those with perceptions of reduced economic mobility since the enactment of NAFTA were significantly more likely to have …

The Language Content Of Computer-Mediated Versus Face-To-Face Motivational-Type Interviews, Karla Deyanira Llanes

Open Access Theses & Dissertations

Motivational Interviewing (MI) is an extensively used technique to facilitate behavior change by increasing a person's own motivation and commitment toward change. Recently, several innovative and effective ways to conduct motivational interviews have emerged. However, one potential option has not been investigated: the utility of conducting a motivational interview via computer. The current study begins to address this gap in knowledge by comparing the language content of computer-mediated motivational-type interviews and face-to-face motivational-type interviews. The motivational-type interviews were conducted with young adults who reported ambivalence about their level of recreational marijuana use. Specifically, non-marijuana users, occasional marijuana users, and frequent …

The Effectiveness Of The Natural Ear On Adults Ability To Accurately Match Pitch, Kendra Nicole Rosales

Open Access Theses & Dissertations

Background: Many theories, such as oral motor, perceptual, and sensorimotor deficits, have been posited to explain inaccurate pitch matching abilities. The current study identifies with the sensorimotor deficit theory and found it to be the most plausible explanation for inaccurate singing abilities. The Natural Ear (NE) program was designed to process voice productions in real-time and filter out the discordant harmonics, allowing a person to hear only their F0.

Purpose: The purpose of this study was to examine the effectiveness of the Natural Ear program in increasing pitch matching accuracy in singers.

Methods: A total of 50 participants were included …

Functional Investigation Of A Brainstem Excitatory Connection Relevant To Sensorimotor Gating, Luis Enrique Martinetti

Open Access Theses & Dissertations

To focus attention, our brain has to "gate" or block irrelevant sensory information that could lead to brain overload. This is done by way of a neuronal pre-attentive mechanism termed sensorimotor gating (SG). Therefore, deficits in the SG mechanism prevent patients from focusing attention. SG deficits have been observed in patients suffering from various neurological disorders, and it is a hallmark of schizophrenia. Previous work has identified key brain areas, such as the pedunculopontine tegmental nucleus (PPTg), that send inputs to the brainstem to regulate SG. However, there is still a knowledge gap concerning what cell types are involved and …

Comparative Phylogeography, Taxonomy, And Neuroanatomy Of Montane Chameleons In The Albertine Rift, Central Africa, Daniel Hughes

Open Access Theses & Dissertations

How do traits vary across the tree of life? Our ability to address this question is diminished if: A taxonomic group has a poorly sampled phylogeny, a species goes extinct before their systematic position is resolved, or a trait is inadequately characterized for detailed studies. In the current era of mass extinction, it is imperative to not only accelerate species discovery through traditional studies in taxonomy and expeditionary research, but also to increase rescue efforts for all types of data before poorly understood species and potentially undescribed traits are lost. Here, an integrative taxonomic approach was used and novel methods …

Insulin Modulates The Strong Reinforcing Effects Of Nicotine And Changes In Insulin Biomarkers In A Rodent Model Of Diabetes, Bryan Cruz

Open Access Theses & Dissertations

This study examined whether the strong reinforcing effects of nicotine and changes in insulin biomarkers observed in diabetic rats are modulated via insulin. A model of diabetes was employed involving administration of streptozotocin (STZ), which produces hypoinsulinemia in rats. The present study included vehicle- or STZ-treated rats that received sham surgery or an insulin pellet. Two-weeks later, the rats were given extended access to intravenous self-administration (IVSA) of saline or nicotine. Concomitant changes in food intake, water responses, and body weight were assessed during 12 days of IVSA. After the last session, plasma levels of insulin, leptin, amylin, and glucagon-like …

Octopamine In Sexual Behavior, Ana Isabel Fernandez

Open Access Theses & Dissertations

Octopamine is a biogenic amine neuromodulator present in neuronal and non-neuronal tissues in invertebrates (Roeder, 1999). It modulates numerous physiological processes such as motivation, pheromone response, olfaction, ovulation, learning and memory. Octopamine together with its precursor tyramine have roles restricted only to invertebrates (Roeder, 1999). It is believed that octopamine is the invertebrate homolog of norepinephrine, a catecholamine present in mammals that acts as a neuromodulator in the sympathetic and central nervous systems. Both octopamine and norepinephrine are derived from the same amino acid tyrosine and are monoamine neurotransmitters. The main objective of this study is to understand the role …

A Behavioral And Neuroimmune System Model Of The Effects Of Chronic Low-Level Lead Exposure In Young Male C57bl/6j Mice, Mayra Gisel Flores-Montoya

Open Access Theses & Dissertations

Chronic low-level lead exposure reduces memory in children however the brain mechanisms mediating these effects are not known. In previous studies we showed that early lead exposure reduced olfactory memory and exploratory behavior in young mice, and reduced microglia cell density in hippocampus/dentate gyrus. The present studies aimed to identify additional behavioral tests that were sensitive to early low-level lead exposure in young mice; and to examine whether microglia upregulated factors known to promote cell migration. Seventy-two C57BL/6J male mice were exposed to 0 ppm (controls), 30 ppm (low-dose), or 430 ppm (high-dose) of lead acetate via dams' milk from …

The Neuromodulatory Mechanisms That Monoamines Control Simple And Complex Behaviors, Paul Rafael Bermeo Sabandal

Open Access Theses & Dissertations

For my Dissertation, I worked on three projects in the fruit fly Drosophila melanogaster, which is a well-established genetic animal model. The first project (Chapter 1) is to elucidate the neural, cellular and molecular mechanisms underlying behavioral control named response inhibition. In this study, I identified that a particular subset of dopamine neurons, D1 dopamine receptors and the neural substrates crucial for response inhibition. Abnormal response inhibition is associated with the mental disorders including attention deficit hyperactivity disorder (ADHD), autism, schizophrenia, obsessive compulsive disorder, posttraumatic stress disorder and addiction, This study may help enhance our understanding the pathogenesis mechanisms of …

4-Nonylphenol Induces Neurodegeneration By Altering Cytoskeleton, Cynthia Carreon

Open Access Theses & Dissertations

4-nonylphenol (4-NP), an endocrine-disrupting compound (EDC), has been shown to affect brain development and may cause neurodegeneration. In the environment, 4-NP arises as a degradation product of alkylphenol polyethoxylates, compounds widely used as nonionic surfactants in commercial production, as well as in herbicides, pesticides, polystyrene plastics, and paints and has been shown to undergo a high level of accumulation in biological tissues. However, the mechanism by which 4-NP exerts its effect is not understood. Recent results from our laboratory indicate that Gβγ, an important component of the G protein-signaling pathway, induces neuronal outgrowth and differentiation by modulating microtubule (MT) assembly, …

Characterization Of Sex Differences In The Reinforcing Effects Of Nicotine, Rodolfo Jesus Flores Garcia

Open Access Theses & Dissertations

It is presently unclear whether ovarian hormones, such as estradiol (E2) promote the reinforcing effects of nicotine in females. Thus, we compared extended access to nicotine intravenous self-administration (IVSA) in intact male, intact female, and OVX female rats (Study 1) as well as OVX females that received vehicle or E2 supplementation (Study 2). The E2 supplementation procedure involved a 4-day procedure involving 2 days of vehicle administration and 2 days of E2 administration. Two doses of E2 (25 or 250 ug) were assessed in separate groups of OVX females in order to examine the dose-dependent effects of this hormone on …

The Metabolically Sentient Arcuate Nucleus: A Functional, Chemoarchitectural And Connectional Study In The Adult Male Rat, Anais Martinez

Open Access Theses & Dissertations

As the obesity pandemic continues to increase, so does the incidence rate of related conditions including diabetes, cardiovascular disease, and neurodegenerative disorders (Yu and Kim 2012). At the level of the brain, the hypothalamus is a key structure for the integratration of autonomic, neuroendocrine and somatomotor functions for the control of metabolism and homeostasis. It has long been implicated as a critical player in the deregulation of an animal's energy status and in the onset of obesity, diabetes and metabolic syndrome (Elmquist et al., 1999). While many ongoing studies are aimed at preventing or treating these conditions, the underlying mechanisms …

Predatory Behavior And Neuroanatomy Of The Sessile Rotifer, Cupelopagis Vorax , Elizabeth Preza

Open Access Theses & Dissertations

Predator-prey interactions contribute to the evolution of behavioral and morphological characteristics of species. However, research on zooplankton has mainly focused on planktonic species such Mesocyclops edax (Arthropoda, Cyclopoida) and Asplanchna spp. (Rotifera, Ploima). Cupelopagis vorax (Rotifera, Collothecaceae) provides a unique model for studying the predatory behavior of a sessile species. Cupelopagis was chosen because it is the only rotifer known to exhibit rheotaxic behaviors in the presence of prey and because it undergoes indirect development where non-feeding, free-swimming larvae mature into feeding adults. The integration of behavioral techniques, immunohistochemistry, and confocal microscopy were used to provide insight as to how …

Method & Madness: Advanced Techniques For Characterizing Rat Hypothalamic Chemoarchitecture And For Modernizing Legacy Data, Claire Eugenia Wells

Open Access Theses & Dissertations

The hypothalamus is a region of the brain with exceptionally high anatomical, chemical, and functional diversity. It regulates homeostatic functions and a number of motivated behaviors impacting homeostasis, such as ingestion and reproduction; it also serves as a point of connection between the forebrain and hindbrain. An improved understanding of the chemical anatomy of this area would benefit scientists working in many neuroscientific disciplines. The work described herein contributes to a chemoarchitectural atlas of the rat hypothalamus, which will include data on the distribution of various hypothalamic neurotransmitters, and on their co-localizations and synaptic interactions. Importantly, the methodology used to …

Characterization Of A Putative Glycinergic Nigropallidal Pathway In The Rodent Brain, Rosalia Ortega

Open Access Theses & Dissertations

Glycinergic neurotransmission is essential for the function of sensory and motor systems associated with pain transmission and rhythmic motor patterns. Yet, the way glycinergic circuits modulates motor systems via the globus pallidus external (GPe) is not clear. The cyto-architecture of glycinergic circuitry is poorly understood and most work has focused in brainstem areas. It is believed that glycinergic neurons are mainly interneurons regulating local circuits. However, it is now becoming clear that they are also projection neurons, constituting true neuronal circuits. At the glycinergic synapse, termination of neurotransmission and recycling of glycine is regulated by two transporters, glycine transporter 1 …

Characterization Of A Medial Prefrontal Cortex - Caudal Pontine Reticular Nucleus Relevant To Sensorimotor Gating, Sebastian Andres Pace

Open Access Theses & Dissertations

Focusing attention depends on filtering irrelevant sensory stimuli to prevent brain overload. This ability of our brain to block or “gate” such information is a pre-attentive neuronal mechanism known as sensorimotor gating (SG). SG abnormalities have been linked to a variety of psychiatric disorders, including schizophrenia. Initial studies related to the SG circuitry were performed more than four decades ago (Graham, 1975). However, SG is still the subject of numerous current studies involving both humans and animal models. Despite these research efforts, knowledge gaps persist regarding the identity neurons involved, their locations in different brain regions and their precise functional …

Examination Of The Rewarding Effects Of Nicotine And The Negative Effects Of Withdrawal In A Rodent Model Of Diabetes, Joseph Allan Pipkin

Open Access Theses & Dissertations

Introduction: The present study utilized a rodent model of diabetes to examine the rewarding effects of nicotine as well as negative affective states and physical signs of withdrawal from this drug. Methods: Separate groups of rats received systemic administration of vehicle or streptozotocin (STZ), which destroys the insulin-producing beta cells in the pancreas and elevates plasma glucose levels. Place conditioning procedures were utilized to compare the rewarding effects of various doses of nicotine (conditioned place preference; CPP) and the aversive effects of nicotine withdrawal (conditioned place aversion; CPA) in vehicle- and STZ-treated rats. CPA and physical signs of withdrawal were …

Mental Health Help-Seeking Intention And Organizational Climate In A Population Of Military Service Members, Mishaw Tyron Cuyler

Open Access Theses & Dissertations

Historically, psychological effects of war such as Post Traumatic Stress Disorder (PTSD) have been understated and misdiagnosed throughout the world. Military members that displayed symptoms of PTSD such as anxiety, depression, and sadness were thought to lack the strength and courage necessary to be a soldier. As a result, many soldiers suffering from symptoms of PTSD would suffer in silence and not seek the requisite help for mental health care. This Dissertation examines the mental health help-seeking intention of U.S. military service members using the Theory of Planned Behavior (TPB). Additionally, this Dissertation considers the effects that leadership support climate …

Macro- And Mesoscale Analysis Of Connections Between The Cingulate Region And The Lateral Hypothalamic Area: Tracer Co-Injection And Chemoarchitectural Studies In The Adult Male Rat, Kenichiro Negishi

Open Access Theses & Dissertations

Hypothalamic research since the middle of the 20th century shaped the view that the lateral hypothalamic area (LHA) has a central role in controlling appetitive drives. The LHA is anatomically positioned to receive converging axonal inputs which relay information about the body's metabolic state as well as descending projections from the cerebral hemispheres, which encode cognitive and emotional states that influence feeding. Cerebral inputs are capable of initiating feeding despite the presence of competing satiety signals. Recent work has shown that medial prefrontal cortical areas can drive feeding in sated animals, possibly by engaging hypothalamic hypocretin/orexin (H/O)-expressing neurons, which are …

Echoes, Sarah Abigail Adleman

Open Access Theses & Dissertations

When I was sixteen, my mother was killed one evening while running on the bayou behind our house in Houston. The man, who is now on Death Row in Texas, beat, raped, and then strangled her to death. Writer Mary Cappello says of Creative Nonfiction, to compose discursively requires that we turn in the direction of the discourses that have made us who we are rather than start from a place of what we think happened to us in the course of our lives. She goes on further to say, Creative nonfiction appreciates the power of prepositions. Instead of writing …