Neuroscience and Neurobiology Commons^™

Septotemporal Variation In Theta Rhythm Dynamics: Effects Of Speed And Habituation, James Hinman

Master's Theses

Theta (6-12 Hz) field potentials and the synchronization (coherence) of these potentials present neural network indices of hippocampal physiology. Theta signals within the hippocampal formation may reflect alterations in sensorimotor integration, the flow of sensory input and/or distinct cognitive operations. While the power and coherence of theta signals vary across lamina within the septal hippocampus, limited information is available about variation in these indices across the septotemporal (long) or areal axis. The present study examined the relationship of locomotor speed to theta indices at CA1 and DG sites across the septotemporal axis as well as in the entorhinal cortex. Our …

Septal Modulation Of The Hippocampus, Siew Kian Tai

Electronic Thesis and Dissertation Repository

The medial septum (MS) is the main source of acetylcholine to the hippocampus, a structure involved in memory and Alzheimer’s disease (AD). Learning and memory involve long-term changes in synaptic strengths, and are suggested to be facilitated by a brain wave, theta rhythm in the hippocampus. Since medial septal neurons influence hippocampal neural activity, lesion of two neuronal populations in the MS, cholinergic and GABAergic, was performed by intraseptal infusion of 192 IgG-saporin and orexin-saporin, respectively. I hypothesized that 1) activation of cholinergic cells by vestibular stimulation induces an atropine-sensitive theta rhythm, modulates synaptic transmission and enhances long-term potentiation (LTP), …

Change Detection Memory In Rhesus Monkeys And Humans, Lauren C. Elmore

Dissertations & Theses (Open Access)

Visual short-term memory (VSTM) is the storage of visual information over a brief time period (usually a few seconds or less). Over the past decade, the most popular task for studying VSTM in humans has been the change detection task. In this task, subjects must remember several visual items per trial in order to identify a change following a brief delay interval. Results from change detection tasks have shown that VSTM is limited; humans are only able to accurately hold a few visual items in mind over a brief delay. However, there has been much debate in regard to the …

Conformational Changes In The Extracellular Domain Of Glutamate Receptors, Anu Rambhadran

Dissertations & Theses (Open Access)

The family of membrane protein called glutamate receptors play an important role in the central nervous system in mediating signaling between neurons. Glutamate receptors are involved in the elaborate game that nerve cells play with each other in order to control movement, memory, and learning.

Neurons achieve this communication by rapidly converting electrical signals into chemical signals and then converting them back into electrical signals. To propagate an electrical impulse, neurons in the brain launch bursts of neurotransmitter molecules like glutamate at the junction between neurons, called the synapse. Glutamate receptors are found lodged in the membranes of the post-synaptic …

The Dissociation Of Location And Object Working Memory Using Fmri And Meg, Antony Passaro

Dissertations & Theses (Open Access)

Visual working memory (VWM) involves maintaining and processing visual information, often for the purpose of making immediate decisions. Neuroimaging experiments of VWM provide evidence in support of a neural system mainly involving a fronto-parietal neuronal network, but the role of specific brain areas is less clear. A proposal that has recently generated considerable debate suggests that a dissociation of object and location VWM occurs within the prefrontal cortex, in dorsal and ventral regions, respectively. However, re-examination of the relevant literature presents a more robust distribution suggestive of a general caudal-rostral dissociation from occipital and parietal structures, caudally, to prefrontal regions, …

Definition Of The Landscape Of Chromatin Structure At The Frataxin Gene In Friedreich’S Ataxia, Eunah Kim

Dissertations & Theses (Open Access)

Friedreich’s ataxia (FRDA) is caused by the transcriptional silencing of the frataxin (FXN) gene. FRDA patients have expansion of GAA repeats in intron 1 of the FXN gene in both alleles. A number of studies demonstrated that specific histone deacetylase inhibitors (HDACi) affect either histone modifications at the FXN gene or FXN expression in FRDA cells, indicating that the hyperexpanded GAA repeat may facilitate heterochromatin formation. However, the correlation between chromatin structure and transcription at the FXN gene is currently limited due to a lack of more detailed analysis. Therefore, I analyzed the effects of the hyperexpanded GAA …

Localization Of Sources Producing Substrate-Borne Vibrations By The Fiddler Crab, Rachel Keiper

Chancellor’s Honors Program Projects

No abstract provided.

Dissociated Functional Pathways For Appetitive And Consummatory Reproductive Behaviors In Male Syrian Hamsters (Mesocricetus Auratus), Laura E. Been

Neuroscience Institute Dissertations

In many species, including Syrian hamsters, male reproductive behavior depends on the perception of odor cues from conspecifics in the environment. Volatile odor cues are processed primarily by the main olfactory system, whereas non-volatile cues are processed primarily by the accessory olfactory system. Together, these two chemosensory systems mediate appetitive reproductive behaviors, such as attraction to female odors, and consummatory reproductive behaviors, such as copulation, in male Syrian hamsters. Main and accessory olfactory information are first integrated in the medial amygdala (MA), a limbic nucleus that is critical for the expression of reproductive behaviors. MA is densely interconnected with other …

Effects Of Methamphetamine On Sexual Behavior, Karla S. Frohmader

Electronic Thesis and Dissertation Repository

Methamphetamine (Meth) is a highly addictive psychostimulant associated with enhanced sexual desire, arousal, and sexual pleasure. Moreover, Meth abuse is frequently linked with the practice of sexual risk behavior and increased prevalence of Human Immunodeficiency Virus (HIV). Currently, the neurobiological basis for this drug-sex nexus is unknown. Moreover, there is a lack of studies investigating the effects of Meth on sexual behavior and more importantly, compulsive sex-seeking behavior, under controlled experimental settings in animal models. First, using immuhistochemistry for mating- and Meth-induced neural activation it was demonstrated that Meth administration in male rats activates neurons in brain regions of the …

Forced-Exercise Dependent Changes In Cellular Immunity: Effects On Experimental Autoimmune Neuritis, Michael W. Calik

Dissertations (6 month embargo)

Guillain-Barré Syndrome (GBS) is a debilitating inflammatory autoimmune disease of the peripheral nervous system that is characterized by rapid-onset paraparesis with areflexia progressing to neuromuscular paralysis. The most common form of GBS observed in North America and Europe is acute inflammatory demyelinating polyneuropathy (AIDP). Enhanced infiltration of pro-inflammatory type 1 helper T (Th1) cells into peripheral nerves of AIDP patients leads to demyelination.

Increasing evidence supports exercise as an effective rehabilitative intervention. Exercise attenuates the onset and progression of autoimmune diseases. Whether exercise alters the progression of GBS remains unclear.

In this study, we determined the effects of forced-exercise on …

Serotonin 1a Receptor Signaling In The Hypothalamic Paraventricular Nucleus Of The Peripubertal Rat, Maureen Lynn Petrunich Rutherford

Dissertations (6 month embargo)

Serotonin (5-HT) is a ubiquitous neurotransmitter in the brain that is involved in various physiologic functions including the regulation of hypothalamic hormones and has been implicated in various mood disorders such as depression. Preclinical and clinical data from studies in adults have shown that antidepressant drugs produce time-dependent changes in serotonergic and other systems and can also normalize dysfunction associated with the hypothalamic-pituitary-adrenal (HPA) axis. To date, our understanding of the mechanisms of 5-HT receptor signaling and the actions of drugs on serotonergic function have been derived from extensive preclinical research carried out using cell lines in vitro or in …

Decoding Motor Intentions From Human Brain Activity, Jason P. Gallivan

Electronic Thesis and Dissertation Repository

“You read my mind.” Although this simple everyday expression implies ‘knowledge or understanding’ of another’s thinking, true ‘mind-reading’ capabilities implicitly seem constrained to the domains of Hollywood and science-fiction. In the field of sensorimotor neuroscience, however, significant progress in this area has come from mapping characteristic changes in brain activity that occur prior to an action being initiated. For instance, invasive neural recordings in non-human primates have significantly increased our understanding of how highly cognitive and abstract processes like intentions and decisions are represented in the brain by showing that it is possible to decode or ‘predict’ upcoming sensorimotor …

Analysis Of Chlamydia Pneumoniae And Ad-Like Pathology In The Brains Of Balb/C Mice Following Direct Intracranial Infection With Chlamydia Pneumoniae, Jessica Rachel Barton

PCOM Biomedical Studies Student Scholarship

Alzheimer’s disease (AD) is an age-related progressive neurodegenerative disorder and the most common form of dementia. The pathology in the central nervous system (CNS) impairs memory and cognition, hindering the capabilities and the quality of life of the individual. This project continues studying the role of infection and Alzheimer’s disease and contributes to the overall understanding of the possible causes of this disease. In this study, BALB/c mice were infected, via direct intracranial injection, with a respiratory isolate (AR-39) of Chlamydia pneumoniae. Their brains were analyzed at 7 and 14 days post-infection, using immunohistochemistry, for the presence of C. …

The Role Of The Androgen Receptor Cofactor P44/Wdr77 In Astrocyte Activation, Bryce H. Vincent

Dissertations & Theses (Open Access)

Astrogliosis is induced by neuronal damage and is also a pathological feature of the major aging-related neurodegenerative disorders. The mechanisms that control the cascade of astrogliosis have not been well established. In a previous study, we identified a novel androgen receptor (AR)-interacting protein (p44/WDR77) and found that it plays a critical role in the control of proliferation and differentiation of prostate epithelial cells. In the present study, we found that deletion of the p44 gene in the mouse brain caused accelerated aging with dramatic astrogliosis. The p44/WDR77 is expressed in astrocytes and loss of p44/WDR77 expression in astrocytes leads to …

Upregulation Of Reactive Oxygen Species During The Retrovirus Life Cycle And Their Roles In A Mutant Of Moloney Murine Leukemia Virus, Ts1-Mediated Neurodegeneration, Soo Jin Kim

Dissertations & Theses (Open Access)

Viral invasion of the central nervous system (CNS) and development of neurological symptoms is a characteristic of many retroviruses. The mechanism by which retrovirus infection causes neurological dysfunction has yet to be fully elucidated. Given the complexity of the retrovirus-mediated neuropathogenesis, studies using small animal models are extremely valuable. Our laboratory has used a mutant moloney murine leukemia retrovirus, ts1-mediated neurodegneration. We hypothesize that astrocytes play an important role in ts1-induced neurodegeneration since they are retroviral reservoirs and supporting cells for neurons. It has been shown that ts1 is able to infect astrocytes in vivo and in …

Study Of Rest As A Negative Regulator Of P16ink4a, Monica B. Gireud

Dissertations & Theses (Open Access)

STUDY OF REST AS A NEGATIVE REGULATOR OF P16^INK4A

Monica Gireud, B.S.

Thesis Advisor: Vidya Gopalakrishnan, Ph.D.

The RE1 Silencing Transcription Factor (REST) is a negative regulator of neuronal differentiation. It is expressed ubiquitously in early embryos, but downregulated in neural progenitors concomitant with onset of neuronal differentiation in these cells. REST has been widely studied as a negative regulator of neuronal differentiation genes. Our recent work identified a novel role for REST in control of cell proliferation. However, the underlying molecular mechanism(s) are not known and is a focus of the current thesis project. Here, we provide evidence …

Nuclear Receptors In Ecdysone-Mediated Programmed Cell Death In Drosophila Melanogaster, Ritika Sehgal

Masters Theses

The steroid hormone ecdysone plays vital roles during Drosophila development. Pulses of 20E during Drosophila life cycle function as temporal cues, signaling the onset of metamorphic processes, including the stage specific programmed cell death of larval tissues. Ecdysone is the critical developmental cue orchestrating the metamorphic reformation of CNS, resulting in the formation of adult-specific neural circuitry. Ecdysone signaling is transduced by a heterodimeric receptor complex formed between two nuclear receptors: EcR and Ultraspiracle (USP). There are 18 nuclear receptors known in Drosophila and EcR is the only receptor whose functions in neuronal PCD have been well recognized. Therefore, the …

Attenuated Effects Of Opiates In Adolescent Vs. Adult Male Rats: Reinforcement, Relapse, And Withdrawal, James M. Doherty

Neuroscience Institute Dissertations

Adolescence in humans is a vulnerable period for illicit drug use, and teenage onset of drug use is associated with long-term addiction. Adolescent sensitivity to drug reinforcement, relapse, and withdrawal has not been explored thoroughly in animal models, especially considering opiate drugs such as morphine and heroin. The present series of studies profiles adolescent sensitivity to opiates using adolescent and adult male rats to test for age differences in opiate self-administration, reinstatement, withdrawal signs, locomotor sensitization, and even brain activation during drug-seeking. To test for acute sensitivity to the reinforcing effects of morphine or heroin, we compared patterns of self-administration …

Investigation Of Mirnas Expression In A Citron-Kinase Mutant Model Of Microcephaly, Shan Parikh

Master's Theses

Mutation of Citron-Kinase (Cit-K) in rodents causes substantial reductions in the number of neurons generated in the CNS and results in a primary microcephaly-like phenotype. Evidence from drosophila genetics has further established a genetic link between Cit-K and a protein Argonaut 1 (AGO1), which is required for proper functioning of the miRNA machinery (2). Experiments characterizing the role of miRNAs in the developing cortex demonstrate the requirement of miRNAs for differentiation of neural progenitor cells starting at embryonic day 12.5 (3). Together, this evidence links the role of miRNAs to neurogenesis and thus this relationship warrants further investigation. Here miRNA …

Hemispheric Specialization For Musical Structure Processing: A Dichotic Listening Study, Deirdre M. Finnegan

Honors Theses

In a dichotic listening study using a musical priming paradigm Hoch and Tillman (2010) found a left-ear advantage for the tonal function effect on spoken syllable identification, suggesting a right-hemispheric specialization for musical structure processing. A pilot study was performed using healthy right-handed non-musician participants to investigate the possible moderating effects of the Hoch and Tillman (2010) findings caused by alternating response hand as well as response key orientation. Several interactions were found which indicated that response hand and response key orientation moderated task performance. Modulations appeared to be due to a Coherence between response hand and response key orientation, …

Investigation Of The Temporal Characteristics Of Absolute Pitch And Relative Pitch Using Eeg, Caitlin E. Miner

Honors Theses

Itoh, Suwazono, Arao, Miyazaki, and Nakada, (2005) compared relative pitch (RP), with absolute pitch (AP) and found a left posterior-temporal negative Event Related Potential (ERP) at 150ms for pitch listening and pitch naming in AP. The present study tested if AP is due to pitch expertise that is not present in RP by comparing pitch naming with instrument naming. Recordings were performed during instrument naming, instrument listening, pitch naming, and pitch listening tasks. At a negatively deflected ERP (156-228ms) a three-way interaction was found, such that voltage differed between instrument listening and instrument naming tasks, but not between pitch listening …

Virtual And Live Social Facilitation While Exergaming: Competitiveness Moderates, Amanda L. Snyder

Honors Theses

This study evaluated the effects of virtual and live social facilitation on exercise behavior using a cybercycle, a virtual reality-enhanced stationary bike, with 3D scenery and interactive races. Research has shown that social presence can enhance performance (Zajonc, 1965). Research with the cybercycle found that more competitive participants increased exercise intensity with the introduction of a virtual competitor (Snyder et al., 2010). The current study extended the prior experimental design by comparing virtual with live social presence. After training to ride the cybercycle, female college students rode in the presence of a virtual rider and live rider (randomly ordered); a …

Neuropsychological And Neurophysiological Effects Of Low-Intensity Strengthening Exercise On Cognition, Vadim V. Yerokhin

Honors Theses

With the growing aging population, it’s becoming increasingly important to find ways to either deter or prevent dementia. To date, most research has concentrated on the effects of aerobic exercise on cognition. Unfortunately, a large portion of older adults are often contraindicated to perform aerobic exercise due to different risk factors, which increase with age. Alas, alternate ways of exercise are necessary. Low-intensity strengthening exercise is a type of exercise aimed at improving balance and strengthening muscles without requiring one to overstrain. The current 11-week long exercise study test neuropsychological effects of exercise with a neuropsychological battery and neurophysiological effects …

Electrophysiological Indices Of Aesthetically Stimulated Processes In Art-Experienced Individuals As Compared To Art-Naïve Individuals, Katharine E. Hartnack

Honors Theses

Aesthetic judgment processes were investigated in art-experienced and art-naïve individuals. Previous electrophysiological data suggest that aesthetic judgment is a two-stage process (Hofel & Jacobson, 2007). The first stage of aesthetic judgment is impression formation which is not spontaneous, and is reflected by an early Event Related Potential (ERP) frontocentral deflection. The second stage reflected by a lateralized late ERP positivity, evaluative categorization is also not spontaneous. Participants in the current study were instructed to either simply view black and white geometric patterns or were instructed to contemplate the beauty of the patterns. Results suggest that aesthetically stimulated processes differ between …

Discerning Prey From Predator In Dragonflies, Melanie Lolier

Honors Theses

The dragonfly is a visual predator that feeds on small flying insects. Because of their high rate of hunting success, dragonflies must have the ability to efficiently discern prey and predator from natural surroundings. In this study, we investigated the extent to which visual flight-control neurons in dragonflies are able to differentiate stimuli that simulate prey items from those that simulate predators. To do this, we presented fourteen sets of rectangular stimuli varying in height, width, speed, and moved in four directions while recording extracellular neuronal responses from the ventral nerve cord. Each of the rectangular stimulus patterns was moved …

The Neuropsychological Effects Of Combined Physical And Mental Exercise In Schizophrenia, Maggie M. Manning

Honors Theses

People suffering from severe mental disorders encounter many debilitating side effects. Those diagnosed with schizophrenia face a large number of challenges each day. Not only must they endure symptoms, like hallucinations and delusions, commonly associated with the illness, but their higher-level cognitive functioning is further impaired in numerous ways. People with schizophrenia, suffering from thought disorder, battle with a pattern of disorganized thinking in which seemingly simple tasks, i.e attention and memory, are difficult. Negative symptoms include the inability to establish social relationships, and hinder their everyday experiences, including work. Their extremely sedentary lifestyle also negatively impacts engagement in other …

Novel Progestin Signaling Molecules In The Brain: Distribution, Regulation And Molecular Mechanism Of Action, Karlie A. Intlekofer

Open Access Dissertations

Progesterone regulates female reproduction in many ways, yet it is still unclear how signals are conveyed through nuclear and extranuclear receptors. The traditional notion was that progesterone binds classical progesterone receptors to alter gene transcription. This view has been challenged by the discovery of additional progesterone signaling molecules important for progesterone actions in non-neural cells. In granulosa cells, the progesterone receptor membrane component 1 (Pgrmc1) mediates progesterone effects by forming a receptor complex with binding partner, Serpine mRNA binding protein 1, but it is unknown whether these molecules function similarly in the brain. To begin to address these issues, I …

Modulation Of Hypoglossal Motoneurons By Nitric Oxide, Justin Philip Benoit

Master's Theses

Obstructive sleep apnea (OSA)- the occurrence of repetitive episodes of airway obstruction during sleep- is considered a major health problem affecting up to 9% of adults in the United States (Parish & Somers, 2004). The hypoglossal motor nucleus (HMN) controls genioglossus muscle tone and is critically important for maintaining airway patency; loss of excitatory input to the HMN during sleep results in disfacilitation of hypoglossal motoneurons, increased airway resistance and contributes to the development of OSA (Horner R. L., 2007). However, a fundamental question of sleep medicine that remains unresolved is what mechanisms help maintain airway patency during sleep? A …

Delineating The Mechanism(S) Of Bdnf/Trkb Mediated Proliferation In Neuroblastoma, Timothy C. Graham

Dissertations & Theses (Open Access)

Delineating the mechanism(s) of BDNF/TrkB mediated proliferation in Neuroblastoma

Timothy Christopher Graham, B.S.

Supervisory Professor: Patrick Zweidler-McKay, MD/PhD

Neuroblastoma is the most common extra-cranial solid tumor in children, arising from neural crest precursor cells. The neurotrophin receptors (TrkA/B/C) have been implicated as important prognostic markers, linking the biology of the tumor to patient outcome. High expression of TrkA and TrkC receptors have been linked to favorable biological features and high patient survival, while TrkB is expressed in unfavorable, aggressive tumors. Several studies suggest that high levels and activation of TrkB by its ligand brain-derived neurotrophic factor (BDNF) stimulates tumor cell …

The Neural Substrates Of Multisensory Speech Perception, Audrey R. Nath

Dissertations & Theses (Open Access)

Comprehending speech is one of the most important human behaviors, but we are only beginning to understand how the brain accomplishes this difficult task. One key to speech perception seems to be that the brain integrates the independent sources of information available in the auditory and visual modalities in a process known as multisensory integration. This allows speech perception to be accurate, even in environments in which one modality or the other is ambiguous in the context of noise. Previous electrophysiological and functional magnetic resonance imaging (fMRI) experiments have implicated the posterior superior temporal sulcus (STS) in auditory-visual integration of …