Neuroscience and Neurobiology Commons^™

Age Impacts Perineuronal Net Density In The Somatosensory Genital Cortex Independently Of Gonadal Steroid Hormones, Ian D. Warren

Masters Theses

A hallmark of pubertal development is the rise in gonadal hormone secretions and the subsequent onset of sexual behavior. The size of the somatosensory genital cortex increases in response to both this rise in gonadal steroid hormones and sexual experience. However, whether specific markers of brain plasticity are similarly impacted by gonadal hormones during puberty is not known. Perineuronal nets (PNNs) are specialized extracellular matrix structures that unsheathe neurons as they mature, and their maturation coincides with the closure of sensitive periods across several sensory systems. PNNs in somatosensory cortex, as an example, respond to experience-dependent plasticity. Although experience-depended changes …

Destined Failure, Chengjun Pan

Masters Theses

I attempt to examine the complex structure of human communication, explaining why it is bound to fail. By reproducing experienceable phenomena, I demonstrate how they can expose communication structure and reveal the limitations of our perception and symbolization.I divide the process of communication into six stages: input, detection, symbolization, dictionary, interpretation, and output. In this thesis, I examine the flaws and challenges that arise in the first five stages. I argue that reception acts as a filter and that understanding relies on a symbolic system that is full of redundancies. Therefore, every interpretation is destined to be a deviation.

Morphological Characterization Of Two Transgenic Strategies For Genetic Access To Semilunar Granule Neurons In The Mouse Dentate Gyrus, David T. Rexford

Masters Theses

Granule cells (GCs) of the dentate gyrus (DG) have been understood as a homogeneous class of neurons exhibiting a characteristic limited firing pattern. A subtype of GC called a semilunar granule cell (SGC) has been identified exhibiting variant morphology, electrophysiology, and positioning from normal GCs. SGCs represent an emerging novel subpopulation of GCs, however, there is presently no genetic tool to access SGCs separately from normal GCs. To provide access for future in vivo studies of this population, we examined two genetic strategies for putative SGC specificity in mouse brain slices. Morphological analysis was performed for quantitative identification of putative …

Chemosensory Receptors In Berghia Stephanieae: Bioinformatics And Localization, Kelsi L. Watkins

Masters Theses

Chemosensation is achieved through the binding of chemical signals to chemoreceptor proteins embedded in the membranes of sensory neurons. The molecular identity of these receptors, as well as the downstream processing of chemosensory signals, has been well studied in arthropods and vertebrates. However, very little is known about molluscan chemosensation. The identity of chemoreceptor proteins in the nudibranch mollusc Berghia stephanieae are unknown. Data from other protostome and molluscan studies suggest Berghia may use ionotropic receptors for some forms of chemoreception. This study used a bioinformatics approach to identify potential chemosensory ionotropic receptors in the transcriptome of Berghia. A …

An Abductive Argument From Depression And Anxiety To Christian Personal Holiness, Kelly Douglas Burchett

Masters Theses

The science on pathological depression and anxiety (D&A) describes religion and spirituality's (R/S) insulating and immunizing effects in roughly 72 to 85 percent of all relevant articles. But the descriptivism of science cannot assign any normative value to a theological worldview. Deductive logic favors theism via Leibnizian contingency, Kalām cosmology, objective morality, fine-tuning of the universe, and abstract conceptualism. The information in DNA, the irreducible complexity of intracellular machinery, the improbability of folded proteins, and the support for common modular design over common ancestry establish a design inference for all of life. Unguided naturalistic simulations fail to surmount the complexity …

The Time Course And Neuroanatomy Of Rhinophore Regeneration In The Nudibranch Berghia Stephanieae, Ani Maroyan

Masters Theses

Within five weeks, the nudibranch, Berghia stephanieae (Gastropoda, Mollusca) can regenerate a severed rhinophore, the main olfactory appendage, such that it is indistinguishable from a non-lesioned rhinophore. The rhinophore is a 2 mm long stalk with lateral sides covered in ridges and the distal third covered in fluorescent pigmentation. Its internal morphology is dominated by longitudinal musculature, overlaid by a complex neuronal plexus, which contains neurons that express various neuroactive substances including serotonin and small cardioactive peptide (SCP). Two large nerves originate in the rhinophore ganglion at the base of the rhinophore and run the length of the rhinophore. To …

Development Of A New Behavioral Assay For Juvenile Berghia Stephanieae, Kelly E. Fischer

Masters Theses

Developing robust behavioral assays to study olfactory-driven behaviors allows for greater insight into the neural mechanisms behind them. Oftentimes, olfactory behavioral assays require a two-choice design, consistent variables, and controlled stimulus application. This can be challenging when working with marine dwelling organisms such as nudibranchs. Extensive work shows the importance of olfaction in both pre-metamorphic larval development and adult stage nudibranchs (Gastropoda, Mollusca). However, there is little research investigating how olfaction plays a role in rapidly developing, post-metamorphic juvenile nudibranchs such as Berghia stephanieae. To study olfactory-associated behaviors in juvenile Berghia, a novel behavioral microfluidic chip was designed which …

Sensory Representation Of Social Stimuli In Aromatase Expressing Neurons In The Medial Amygdala, Charles J. Gualtieri

Masters Theses

The ability of animals to sense, interpret, and respond appropriately to social stimuli in their environment is essential for identifying and distinguishing between members of their own species. In mammals, social interactions both within and across species play a key role in determining if an animal will live to pass on its genes to the next generation or else be removed from the gene pool. The result of this selection pressure can be observed in specialized neural circuits that respond to social stimuli and orchestrate appropriate behavioral responses. This highly conserved network of brain structures is often referred to as …

Effects Of A Circadian Mutation On Adult Neurogenesis, Michael Bahiru

Masters Theses

Rotating shift work, irregular sleep patterns and jetlag disrupt circadian rhythms, induce or aggravate disease, and produce deficits in cognitive function. Internal misalignment, a state in which abnormal phase relationships prevail between and within organs, is widely proposed to account for these adverse effects of circadian disruption. This hypothesis has been difficult to test because phase shifts of the entraining environmental cycle lead to transient desynchrony. Thus, it remains possible that phase shifts, regardless of internal desynchrony, account for adverse effects of circadian disruption. I have used the duper mutant hamster, whose locomotor activity rhythms re-entrain 5-fold faster than wild …

Studies On High-Throughput Single-Neuron Rna Sequencing And Circadian Rhythms In The Nudibranch, Berghia Stephanieae, Thi Bui

Masters Theses

One of the goals of neuroscience is to classify all of the neurons in the brain. Neuronal types can be defined using a combination of morphology, electrophysiology, and gene expression profiles. Gene expression profiles allow differentiation between cells that share similar characteristics. Leveraging the advantage of Berghia stephanieae (Gastropoda; Nudibranchia), which has around 28,000 neurons, I constructed high-throughput single-neuron transcriptomes for its whole brain. I produced a single-cell dissociation protocol and a custom data analysis pipeline for data of this nature. Around 129,000 cells were collected from 18 rhinophore ganglia and 20 circumesophageal ring ganglia (brain), consisting of the cerebropleural, …

Opioids Disrupt Sleep And Wakefulness In C57bl/6j Mice, Clarence E. Locklear

Masters Theses

Opioid use disorder (OUD) is a major public health burden. According to the National Institutes of Health (NIH), studies helping to understand the mechanisms of OUD will help improve prevention and treatment. Opioids long have been shown to disrupt sleep and sleep disruption enhances the likelihood of addiction relapse in humans. The NIH refers to the mouse as one of the most powerful animal systems to study because of the genetic homologies between human and mouse. Prior to the present research, no studies have quantified the effect of opioids on states of sleep and wakefulness in mice. The current study …

Reprograming Neuronal Cells By Overexpression Of Fibroblast-Specific Transcription Factors, Abdulmohsen Alanazi

Masters Theses

In mammals, a complex system of regulatory signals distinguishes tissues, structures and functions. Combinations of transcription factors and co-factors regulate activation and repression of genes that result in cellular differentiation. Whole genome arrays allow the monitoring of genomic expression in specific tissues. Fibroblast microarray studies have shown candidate genes that may be involved in fibroblast identification, including genes that express transcription factors Prrx1, Snai2 and Twist1. A previous study showed that the Prrx1 and Snai2 could reactivate a fibroblast phenotype in hybrid cells that had lost fibroblast identity. Furthermore, overexpression of these factors in liver-derived cells strongly repressed liver gene …

Transcriptome Analysis Of Neuro-2a Cells Treated With Asiatic And Madecassic Acid, Fatimah M. Alqam

Masters Theses

Traditional herbal medicine is ingrained as a source of therapeutic compounds to medicate various diseases. The family Araliaceae (Ginseng family) is rich in traditional medicine species, such as Centella asiatica (CA). For many centuries, CA has been used by the indigenous Indian and Chinese in Ayurvedic and traditional medicine, respectively, to improve intelligence, learning, memory, and cognitive performance. Previous studies on cell culture and animal models supported the beneficial effects of CA on the nervous system. However, the exact composition of CA extract and its molecular mechanism that leads to neuroprotection is still unclear. We examined the effect of asiatic …

Functional Analysis In The Home Setting Of An Older Adult With Neurocognitive Disorder, Emily Norton

Masters Theses

Currently within the behavioral gerontology literature there are no published studies that include a functional assessment in the home setting. The primary goal of the present study was to address this gap by conducting a functional analysis on a challenging behavior of an older adult with neurocognitive disorder in the home. This study occurred in two phases. During phase one, researchers conducted an antecedent functional analysis on the bizarre speech of an 81-year-old female with suspected dementia across four conditions (television on, no interactions initiated; television on, interactions initiated; television off, no interactions initiated; television off, interactions initiated). Results from …

How Perception Of Decision Environment And Future Information Affects Changes In Delay Discounting Rates: Differences Across U.S. And China, Differences Before And After The U.S. 2018 Midterm Elections, Fran Walsh

Masters Theses

In this thesis, I will explore the idea that choices between present, smaller value options and future, larger value options depend on how much individuals trust the future to deliver the reward. Due to this aspect of trust, the individual must build their estimate of trust based on information for their present environment and their future expectations. This estimate of future trust can change across different time points in the same environment (i.e., before and after a national election) and between environments in the same time point (i.e., between two countries experiencing different economic rates of change). In this set …

Sex Specific Electrophysiology Of Aromatase Neurons In The Medial Amygdala, Marcelo Henrique Correia

Masters Theses

The medial amygdala (MeA) is a central node in the interwoven circuits that regulate social behavior based on pheromones. Aromatase-expressing (arom⁺) neurons in the MeA are key for the establishment and maintenance of sex differences. Here, we characterized the intrinsic electrophysiological properties of arom⁺ neurons and non-aromatase (arom^-) neurons in the MeA of male and female mice. Most electrophysiological properties were similar for arom⁺ neurons in the MeA between sexes, but the relative refractory period was twice as large in female mice. We also show that the firing pattern and firing frequency is markedly …

Analysis Of Connectivity In Emg Signals To Examine Neural Correlations In Muscular Activation Of Lower Leg Muscles For Postural Stability, Diana Mccrumb

Masters Theses

In quiet standing the central nervous systems implements a pre-programmed ankle strategy of postural control to maintain upright balance and stability. This strategy is comprised of a synchronized common neural drive being delivered to synergistically grouped muscles. In this study connectivity between EMG signals of unilateral and bilateral homologous muscle pairs, of the lower legs, during various standing balance conditions was evaluated using magnitude squared coherence (MSC) and mutual information (MI). The leg muscles of interest were the tibialis anterior (TA), medial gastrocnemius (MG), and the soleus (S) of both legs. MSC is a linear measure of the phase relation …

Changes In Color Guidance Over The Course Of A Complex Visual Search, Ryan Papargiris

Masters Theses

When searching for an object, we store a mental representation of the target, which guides our search through the use of attention. The effectiveness of this search guidance varies depending on the task and the relationship between target and distractors. With a better understanding of how search guidance changes over time within a trial, we can better compare the differences between experimental conditions. Eye tracking data from a variety of search tasks were analyzed to determine how color guidance varied over the course of the trial. Color guidance for a given fixation was evaluated based on the distance in color …

One Year Change In Cognitive Function In Male And Female Common Marmosets (Callithrix Jacchus), Brianna Healey

Masters Theses

Long term cognitive studies in humans and nonhuman primates such as macaques are difficult because of their long lifespan. The common marmoset (Callithrix jacchus) is a non-human primate who shares with humans many features characteristic of primates, including a complex brain and cognitive function. They also have a short lifespan (~10 years) that makes them a great model in studies of cognitive aging. This study focuses on the rate of decline in cognitive function in male and female marmosets based on performance on reversal learning tasks over 2 years of testing.

We found that marmosets improved their overall …

Sex, Motivation, And Reversal Learning In The Common Marmoset (Callithrix Jacchus), Alyssa Carlotto

Masters Theses

This study examined the relationships between motivation and cognitive performance in male and female common marmosets (Callithrix jacchus). This question was driven by prior data from the Lacreuse lab showing a robust female impairment in reversal learning, as assessed by the number of trials needed to acquire a reversal following a simple discrimination between two stimuli. This thesis tested the hypothesis that the female impairment in reversal learning was mediated by deficits in motivation. Two sets of measures were used to test this hypothesis. I evaluated physical effort via testing on the progressive ratio (PR), a test that …

Does Lactobacillus Reuteri Probiotic Treatment Improve Sleep Quality In Rhesus Macaques (Macaca Mulatta) Displaying The Self-Injurious Phenotype?, Peter Mcginn

Masters Theses

Self-injurious behavior (SIB) is a complex phenotype that occurs with an increasing prevalence of about 7-34% in humans and 10-12% in non-human primates (NHPs). This study evaluated the efficacy of probiotic Lactobacillus reuteri as a treatment for self-injurious behavior (SIB) and sleep disruption in rhesus macaques. The treatment was proposed to alleviate mild self-biting, sleep disruption, and reduce chronically elevated hypothalamic-pituitary-adrenocortical (HPA) axis activity, all hallmark features of monkeys with this condition. The probiotic preparation included two strains of L. reuteri (L. reuteri ATCC PTA 6475 & L. reuteri DSM 17938) containing on average 200 million colony forming units …

Mapping A Pup-Responsive Pathway From The Medial Preoptic Area To The Ventral Tegmental Area., Matias Andina

Masters Theses

Maternal behavior is the complex array of caregiving behaviors females display towards offspring. In rats, the transition to motherhood depends on the action of various hormones, especially estradiol near parturition, which primes the maternal circuitry to respond to pups upon first encounter at parturition with appropriate maternal behavior. Although virgin rats avoid pups, new mothers are highly motivated to interact with pups, and their maternal behavior depends on the functional interaction between the medial preoptic area (mPOA) and the ventral tegmental area (VTA). However, a precise mapping of the VTA-projecting mPOA neurons remains to be elucidated. To determine whether pup-responsive …

A Precise Steroid-Responsive Centrifugal Feedback Projection To The Accessory Olfactory Bulb, Tal Inbar

Masters Theses

The accessory olfactory bulb (AOB) processes pheromonal signals which in turn drive social behaviors. Here we identify a tract of aromatase-expressing (arom+) fibers in the dorsal lateral olfactory tract (dLOT) which terminate in the granule cell layer (GCL) of the AOB. We utilized a retrograde tracer in aromatase reporter animals to delineate the source of these fibers. We show that these input fibers emerge almost exclusively from a contiguous population of arom+ neurons that spans the bed nucleus of the accessory olfactory tract (BAOT) and posterioventral subnucleus of the medial amygdala (MeApv). This population of neurons expresses the estrogen receptor …

The Role Of Hypothalamic Vasopressin Cells In Male Sociability And Anxiety-Linked Behavior, Prakruti Nanda

Masters Theses

The vertebrate hypothalamus is a central node within multiple interwoven neural networks that integrate external and internal cues to control homeostasis, endocrine functions and social behavior. The neuropeptide hormone arginine-vasopressin (AVP) is produced in both the supraoptic and paraventricular nuclei of the hypothalamus. Expression within these nuclei is conserved across species, and species differences in the expression of AVP and its cognate receptors correlate with differences in social behavior. As a central node within the social behavior network, chemogenetic manipulation of AVP+ cells in the paraventricular nucleus (pvn) of the hypothalamus provides a unique opportunity to investigate the relationship between …

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 …

Explicit Learning Of Phonotactic Patterns Disrupts Language Learning, Evan Hare

Masters Theses

Learning environment has been proposed to be a cause of age of acquisition effects in second language acquisition. Explicit learning in adults is linked to fast initial gains but poorer ultimate attainment whereas implicit learning in children requires more input but leads to greater proficiency in the long run. The current study used ERP measures to determine if explicit learning of a phonotactic pattern interferes with implicit learning of that same pattern in adults. Listeners were told to figure out the pattern of consonants that can go together in a word by listening to 16 CVCV nonsense words in which …

A Representational-Hierarchical Account: A New Theory Of False Memories, D. Merika Wilson

Masters Theses

Past research has supported a representational-hierarchical theory of memory and perception that extends the ventral visual stream into the medial temporal lobe. In this account, representations are organized in a hierarchical manner, such that structures located further anterior in the brain contain complex representations of whole objects and areas further posterior in the visual cortex contain representations of simple features. When conjunctive representations are compromised, an individual must rely on simple-feature representations to complete mnemonic and perceptual tasks. However, these simple-feature representations are susceptible to feature-level interference, which can cause false recognition of novel objects. The goal of the present …

Effects Of Asiatic Acid On Neurite Outgrowth In Neuro-2a Cells, Aishah Asiri

Masters Theses

Recently, medicinal plants from ancient Ayurvedic medicine have provided clues to the discovery of novel therapeutics for various diseases. In Ayurvedic medicine, a common Indian plant, Centella asiatica is highly regarded as a "rasayana" or nerve tonic. The Centella extract is used to ward off age-related dementia and to increase memory and intelligence. The mechanism by which Centella improves memory and learning and reduces the risk of dementia is unclear.

We recently tested the effects of asiatic acid, the main active component of Centella, on neuronal growth. We hypothesized that asiatic acid will promote neuronal growth and neurite network …

Metabolic And Morphologic Shifts In Neuro2a Cells Cultured In Galactose Medium, Leah Welker

Masters Theses

It has been observed that highly-proliferating cells, such as cancer cells, rely mainly on glycolysis for ATP production, regardless of presence of oxygen. This effect, however, can be reversed by changing the main energy substrate in the medium from glucose to galactose. The oxidation of galactose in glycolysis yields less net ATP, presumably forcing the cell into OXPHOS. This has been established in many cell lines, including HeLA, HepG2, and skeletal muscle cells. As of yet, this has not been reproduced in neuronal cells. Using Neuro2a, a murine neuroblastoma cell line, this study exposes neuronal cells to galactose medium, and …

Probiotics As A Treatment For Increased Nighttime Activity In Rhesus Macaques (Macaca Mulatta) Displaying Self-Injurious Behavior, Lauren L. Stanwicks

Masters Theses

Self-injurious behavior (SIB) is a behavioral pathology seen in a small percentage of humans and non-human primates. In one previous study, macaques with SIB had more sleep disruption than controls, but observations were limited. Two studies were conducted: a baseline study to investigate nighttime activity in rhesus macaques (Macaca mulatta) displaying SIB and controls, and a probiotic study to assess probiotic Bifidobacterium infantis 35624 for high nighttime activity. Subjects were 13 rhesus macaques, 5 with SIB (3 females; 1 SIB). Videocapture of Nighttime Activity (VNRA) was developed to record in complete darkness. IR-receptive webcams were connected to a …