Neurosciences Commons^™

Melanopsin-Expressing Retinal Ganglion Cells In Control Vs. Glaucomatous Retinas, Edward Hamad

Williams Honors College, Honors Research Projects

Glaucoma is a common cause of vision loss worldwide and has a large scope of symptoms, ranging from pupillary reflex defects to sleep disorders. These issues can be explained partially by a recently found subtype of retinal ganglion cells that express melanopsin, denoted melanopsin-expressing retinal ganglion cells or mRGCs for short. These cells function primarily as photoreceptors in the non-image forming pathway, but can receive input from rods and cones. Since mRGCs play a role in the pupillary reflex and regulation of the sleep-wake cycle, I investigated if glaucoma leads to the degeneration of these cells in a mouse model …

Recovery From Visual Dysfunction Following Mild Traumatic Brain Injury Is Associated With Adaptive Reorganization Of Retinal Inputs To Lateral Geniculate Nucleus In The Mouse Model Utilizing Central Fluid Percussion Injury., Vishal C. Patel

Theses and Dissertations

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality nationwide. Prevalence of mild TBI (mTBI) vastly outnumbers more severe forms however the associated morbidity has only recently gained public attention. Visual dysfunction is a significant component of mTBI associated morbidity with recovery of function linked with improvement in global outcomes. Examination of sensory and motor pathways in other brain injury paradigms support that recovery is largely dependent on adaptive plasticity of remaining connections. Current examinations of visual function recovery following mTBI is limited to identifying evidence for recovery and objective evidence for adaptive plasticity is limited. Therefore, …

Investigating The Role Of Integrin Beta 3 In Dendritic Arborization In The Supragranular Developing Cerebral Cortex, Zachary Logan Holley

Senior Honors Projects, 2010-2019

Integrin subunits have been implicated in axonal and dendritic outgrowth. In particular, a strong positive association has been found between mutations in integrin beta 3 (Itgb3) and autism spectrum disorder, but little is known about neuronal Itgb3 function in vivo. Many forms of autism spectrum disorder are thought to arise from dysfunctional dendritic arborization and synaptic pruning. Global knockout of Itgb3 in mice leads to autistic-like behaviors. Itgb3^-/- mice also have reduced callosal volume, a key neuroanatomical correlate of autism. Here, we test the hypothesis that Itgb3 is required for normal dendritic arborization in layer II/III pyramidal …

Quantifying Expression Of Interneuron Subtype Markers For Dlx-2 Transfected Ng2 Cells, Timothy Nolan

Honors Scholar Theses

Neurons are a post-mitotic cell population, and therefore, they are not able to regenerate in vivo after a traumatic injury. Because inhibitory GABAergic interneurons and oligodendrocyte precursor cells (OPCs) are derived from the same precursor, recent studies have focused on transforming these OPCs into GABAergic neurons. However, there are different types of GABAergic interneurons that have different electrophysiological responses, which can lead to functional differences. The Nishiyama laboratory had already used a key gene in GABAergic interneuron and OPC differentiation, Distal-less homeobox 2 (Dlx-2), to transfect OPCs; early electrophysiology tests showed most of these transfected cells behaved like immature neurons, …

Behavioral And Neural Correlates Of Normal Aging Effects On Motor Preparatory Mechanisms Of Speech Production And Limb Movement, Karim Johari, Dirk B. Den Ouden, Roozbeh Behroozmand

Communication Sciences and Disorders Faculty Articles and Research

Normal aging is associated with decline of the sensorimotor mechanisms that support movement function in the human brain. In this study, we used behavioral and event-related potential (ERP) recordings to investigate the effects of normal aging on the motor preparatory mechanisms of speech production and limb movement. The experiment involved two groups of older and younger adults who performed randomized speech vowel vocalization and button press motor reaction time tasks in response to temporally predictable and unpredictable visual stimuli. Behavioral results revealed age-related slowness of motor reaction time only during speech production in response to temporally unpredictable stimuli, and this …

Neuroprotective Strategies Following Experimental Traumatic Brain Injury: Lipid Peroxidation-Derived Aldehyde Scavenging And Inhibition Of Mitochondrial Permeability Transition, Jacqueline Renee Kulbe

Theses and Dissertations--Neuroscience

Traumatic brain injury (TBI) represents a significant health crisis. To date there are no FDA-approved pharmacotherapies available to prevent the neurologic deficits caused by TBI. Following TBI, dysfunctional mitochondria generate reactive oxygen and nitrogen species, initiating lipid peroxidation (LP) and the formation of LP-derived neurotoxic aldehydes, which bind mitochondrial proteins, exacerbating dysfunction and opening of the mitochondrial permeability pore (mPTP), resulting in extrusion of mitochondrial sequestered calcium into the cytosol, and initiating a downstream cascade of calpain activation, spectrin degradation, neurodegeneration and neurologic impairment.

As central mediators of the TBI secondary injury cascade, mitochondria and LP-derived neurotoxic aldehydes make promising …

Manganese-Enhanced Magnetic Resonance Imaging: Overview And Central Nervous System Applications With A Focus On Neurodegeneration, Ryan A. Cloyd, Shon A. Koren, Jose F. Abisambra

Physiology Faculty Publications

Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and …

Hyperhomocysteinemia As A Risk Factor For Vascular Contributions To Cognitive Impairment And Dementia, Brittani R. Price, Donna M. Wilcock, Erica M. Weekman

Physiology Faculty Publications

Behind only Alzheimer’s disease, vascular contributions to cognitive impairment and dementia (VCID) is the second most common cause of dementia, affecting roughly 10–40% of dementia patients. While there is no cure for VCID, several risk factors for VCID, such as diabetes, hypertension, and stroke, have been identified. Elevated plasma levels of homocysteine, termed hyperhomocysteinemia (HHcy), are a major, yet underrecognized, risk factor for VCID. B vitamin deficiency, which is the most common cause of HHcy, is common in the elderly. With B vitamin supplementation being a relatively safe and inexpensive therapeutic, the treatment of HHcy-induced VCID would seem straightforward; however, …

Glimepiride Administered In Chow Reversibly Impairs Glucose Tolerance In Mice, Dana M. Niedowicz, Sabire Özcan, Peter T. Nelson

Sanders-Brown Center on Aging Faculty Publications

Sulfonylureas are a class of antidiabetes medications prescribed to millions of individuals worldwide. Rodents have been used extensively to study sulfonylureas in the laboratory. Here, we report the results of studies treating mice with a sulfonylurea (glimepiride) in order to understand how the drug affects glucose homeostasis and tolerance. We tested the effect of glimepiride on fasting blood glucose, glucose tolerance, and insulin secretion, using glimepiride sourced from a local pharmacy. We also examined the effect on glucagon, gluconeogenesis, and insulin sensitivity. Unexpectedly, glimepiride exposure in mice was associated with fasting hyperglycemia, glucose intolerance, and decreased insulin. There was no …

Spinal Cord Trauma: An Overview Of Normal Structure And Function, Primary And Secondary Mechanisms Of Injury, And Emerging Treatment Modalities, Daniel Morin

Senior Honors Theses

The structures of the spinal cord and vertebral column are designed to provide flexibility, while still providing ample protection for the spinal cord deep within. While it does offer remarkable protection against most routine trauma, the spinal cord is still vulnerable to high-force etiologies of trauma and may become damaged as a result. These events are referred to as primary injury. Following the initial injury, the body’s own physiological responses cause a cascade of deleterious effects, known as secondary injury. Secondary injury is a major therapeutic target in mitigating the effects of spinal cord injury (SCI), and much research is …

Thalamocortical Processing Of Temporal Cues In Sounds, Kasey Smith

Honors Scholar Theses

The ability of the brain to extract meaningful information from complex sounds is what allows mammals to understand species-specific communication as well as important environmental cues such as the sound of water or of potential predators or prey. The auditory cortex of humans and other mammals contains multiple cortical regions that unique sensitivities to both spectral and temporal sound cues. This discourse will explore three main factors proposed to determine these distinct processing capabilities in regard to temporal sound cues; the distribution of glutamate transporters in the thalamus, the architecture of afferent pathways between the thalamus and auditory cortex, and …

Bilateral Facial Spasm Following Guillain-Barré Syndrome, Zain Guduru, John Morgan, Kapil Sethi

Neurology Faculty Publications

Background: We report a patient who developed lower facial muscle spasm at rest and bilateral facial synkinesis several months after treatment of Guillain–Barré syndrome (GBS); this finding, to our knowledge, is hitherto unreported.

Phenomenology Shown: Bilateral synkinesis, facial muscles spasm at rest, bilateral postparalytic facial syndrome.

Educational Value: Aberrant regeneration of nerve fibers post GBS, resulting in facial muscles spasm at rest, bilateral synkinesis.

Amperometric Self-Referencing Ceramic Based Microelectrode Arrays For D-Serine Detection, Diana Campos-Beltrán, Åsa Konradsson-Geuken, Jorge E. Quintero, Lisa Marshall

Neuroscience Faculty Publications

D-serine is the major D-amino acid in the mammalian central nervous system. As the dominant co-agonist of the endogenous synaptic NMDA receptor, D-serine plays a role in synaptic plasticity, learning, and memory. Alterations in D-serine are linked to neuropsychiatric disorders including schizophrenia. Thus, it is of increasing interest to monitor the concentration of D-serine in vivo as a relevant player in dynamic neuron-glia network activity. Here we present a procedure for amperometric detection of D-serine with self-referencing ceramic-based microelectrode arrays (MEAs) coated with D-amino acid oxidase from the yeast Rhodotorula gracilis (RgDAAO). We demonstrate in vitro D-serine recordings with a …

Cortical Thinning And Neuropsychiatric Outcomes In Children Exposed To Prenatal Adversity: A Role For Placental Crh?, Curt A. Sandman, Megan M. Curran, Elyssia Poggi Davis, Laura M. Glynn, Kevin Head, Tallie Z. Baram

Psychology Faculty Articles and Research

Exposure to early life adversity may disrupt the development and maturation of neurons and brain circuits, which, in turn, underlie neurodevelopment and mental illnesses. During fetal life, maternal adversity is conveyed to the developing brain via several molecular signals, including the stress hormone corticotropin releasing hormone (CRH). Employing a large well characterized prospective cohort, we find that fetal exposure to placental-origin CRH levels predicts structural and functional brain outcomes in children. Specifically, elevated placental CRH levels portend thinning of selective cortical regions of exposed individuals, with commensurate cognitive and emotional deficits. Notably, the relations of placental-origin CRH to cortical thinning …

A Gut Feeling: A Hypothesis Of The Role Of The Microbiome In Attention-Deficit/Hyperactivity Disorders., Xue Ming, Neil Chen, Carly Ray, Gretchen Brewer, Jeffrey Kornitzer, Robert A Steer

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Attention-deficit/hyperactivity disorder (ADHD) is a neurologic disorder characterized by hyperactivity/impulsivity and/or inattentiveness, with genetic and environmental factors contributing to the disorder. With the growing recognition of the microbiome's role in many neurological disorders, the authors propose that it may also be implicated in ADHD. Here, we describe several evolving areas of research to support this hypothesis. First, a unique composition of gut bacteria has been identified and linked to behaviors in ADHD. Second, our research found an increased incidence of 2 gastrointestinal symptoms (constipation and flatulence) in children with ADHD, as compared to controls. Finally, emerging data may be interpreted …

Cortical Contribution To Linear, Non-Linear And Frequency Components Of Motor Variability Control During Standing, Niklas König Ignasiak

Physical Therapy Faculty Articles and Research

Motor variability is an inherent feature of all human movements and reflects the quality of functional task performance. Depending on the requirements of the motor task, the human sensory-motor system is thought to be able to flexibly govern the appropriate level of variability. However, it remains unclear which neurophysiological structures are responsible for the control of motor variability. In this study, we tested the contribution of cortical cognitive resources on the control of motor variability (in this case postural sway) using a dual-task paradigm and furthermore observed potential changes in control strategy by evaluating Ia-afferent integration (H-reflex). Twenty healthy subjects …

The Psychology Of Neurofeedback: Clinical Intervention Even If Applied Placebo, Robert T. Thibault, Amir Raz

Psychology Faculty Articles and Research

Advocates of neurofeedback make bold claims concerning brain regulation, treatment of disorders, and mental health. Decades of research and thousands of peer-reviewed publications support neurofeedback using electroencephalography (EEG-nf); yet, few experiments isolate the act of receiving feedback from a specific brain signal as a necessary precursor to obtain the purported benefits. Moreover, while psychosocial parameters including participant motivation and expectation, rather than neurobiological substrates, seem to fuel clinical improvement across a wide range of disorders, for-profit clinics continue to sprout across North America and Europe. Here, we highlight the tenuous evidence supporting EEG-nf and sketch out the weaknesses of this …

Trkb-Enhancer Facilitates Functional Recovery After Traumatic Brain Injury, John Marshall, Joanna Szmydynger-Chodobska, Mengia S. Rioult-Pedotti, Kara Lau, Andrea T. Chin, Siva K. Reddy Kotla, Rakesh Tiwari, Keykavous Parang, Steven W. Threlkeld, Adam Chodobski

Pharmacy Faculty Articles and Research

Brain-derived neurotrophic factor (BDNF), a key player in regulating synaptic strength and learning, is dysregulated following traumatic brain injury (TBI), suggesting that stimulation of BDNF signaling pathways may facilitate functional recovery. This study investigates whether CN2097, a peptidomimetic ligand which targets the synaptic scaffold protein, postsynaptic density protein 95, to enhance downstream signaling of tropomyosin-related kinase B, a receptor for BDNF, can improve neurological function after TBI. Moderate to severe TBI elicits neuroinflammation and c-Jun-N-terminal kinase (JNK) activation, which is associated with memory deficits. Here we demonstrate that CN2097 significantly reduces the post-traumatic synthesis of proinflammatory mediators and inhibits the …

The Motor Cortical Representation Of A Muscle Is Not Homogeneous In Brain Connectivity, Jo Armour Smith, Alaa Albishi, Sarine Babikian, Skulpan Asavasopon, Beth E. Fisher, Jason Kutch

Physical Therapy Faculty Articles and Research

Functional connectivity patterns of the motor cortical representational area of single muscles have not been extensively mapped in humans, particularly for the axial musculature. Functional connectivity may provide a neural substrate for adaptation of muscle activity in axial muscles that have both voluntary and postural functions. The purpose of this study was to combine brain stimulation and neuroimaging to both map the cortical representation of the external oblique (EO) in primary motor cortex (M1) and supplementary motor area (SMA), and to establish the resting-state functional connectivity associated with this representation. Motor evoked potentials were elicited from the EO muscle in …

What Is The Contribution Of Ia-Afference For Regulating Motor Output Variability During Standing?, Niklas König Ignasiak

Physical Therapy Faculty Articles and Research

Motor variability is an inherent feature of all human movements, and describes the system‘s stability and rigidity during the performance of functional motor tasks such as balancing. In order to ensure successful task execution, the nervous system is thought to be able to flexibly select the appropriate level of variability. However, it remains unknown which neurophysiological pathways are utilized for the control of motor output variability. In responding to natural variability (in this example sway), it is plausible that the neuro-physiological response to muscular elongation contributes to restoring a balanced upright posture. In this study, the postural sway of 18 …

Neuroinflammation In Alzheimer's Disease And Vascular Cognitive Impairment, Erica M. Weekman

Theses and Dissertations--Physiology

It was once believed that the brain was immunologically privileged with no resident or infiltrating immune cells; however, now it is understood that the cells of the brain are capable of a wide range of inflammatory processes and phenotypes. Inflammation in the brain has been implicated in several disease processes such as Alzheimer’s disease (AD) and vascular cognitive impairment and dementia (VCID); however, the role of inflammation in these two dementias is poorly understood.

When we stimulated a pro-inflammatory phenotype with an adeno-associated viral vector in a transgenic mouse model of AD that develops Aβ plaques, we saw a pro-inflammatory …

Revealing The Dual Streams Of Speech Processing, Julius Fridriksson, Grigori Yourganov, Leonardo Bonilha, Alexandra Basilakos, Dirk B. Den Ouden, Chris Rorden

Communication Sciences and Disorders Faculty Articles and Research

Several dual route models of human speech processing have been proposed suggesting a large-scale anatomical division between cortical regions that support motor–phonological aspects vs. lexical–semantic aspects of speech processing. However, to date, there is no complete agreement on what areas subserve each route or the nature of interactions across these routes that enables human speech processing. Relying on an extensive behavioral and neuroimaging assessment of a large sample of stroke survivors, we used a data-driven approach using principal components analysis of lesion-symptom mapping to identify brain regions crucial for performance on clusters of behavioral tasks without a priori separation into …

Can Gait Signatures Provide Quantitative Measures For Aiding Clinical Decision-Making? A Systematic Meta-Analysis Of Gait Variability Behavior In Patients With Parkinson’S Disease, Niklas König Ignasiak

Physical Therapy Faculty Articles and Research

A disturbed, inconsistent walking pattern is a common feature of patients with Parkinson's disease (PwPD). Such extreme variability in both temporal and spatial parameters of gait has been associated with unstable walking and an elevated prevalence of falls. However, despite their ability to discretise healthy from pathological function, normative variability values for key gait parameters are still missing. Furthermore, an understanding of each parameter's response to pathology, as well as the inter-parameter relationships, has received little attention. The aim of this systematic literature review and meta-analysis was therefore to define threshold levels for pathological gait variability as well as to …

Reverse Engineering A Kinetic Model Of A Dopaminergic Neuron To Apoptosis, Johnathan Morris

Biology and Medicine Through Mathematics Conference

No abstract provided.

Revealing The Quality Of Movement: A Meta-Analysis Review To Quantify The Thresholds To Pathological Variability During Standing And Walking, Niklas König Ignasiak

Physical Therapy Faculty Articles and Research

Neuromotor processes are inherently noisy, which results in variability during movement and fluctu-ations in motor control. Although controversial, low levels of variability are traditionally considered healthy, while increased levels are thought to be pathological. This systematic review and meta-analysisof the literature investigates the thresholds between healthy and pathological task variability.

After examining 13,195 publications, 109 studies were included. Results from over 3000 healthy sub-jects and 2775 patients revealed an overall positive effect size of pathology on variability of 0.59 forwalking and 0.80 for sway. For the coefficient of variation of stride time (ST) and sway area (SA), upperthresholds of 2.6% …

Manual Unloading Of The Lumbar Spine: Can It Identify Immediate Responders To Mechanical Traction In A Low Back Pain Population? A Study Of Reliability And Criterion Referenced Predictive Validity, John Carlos Jr., Brian T. Swanson, Sean P. Riley, Mark P. Cote, Robin L. Leger, Isaac L. Moss

Faculty Publications

Background:: To date, no research has examined the reliability or predictive validity of manual unloading tests of the lumbar spine to identify potential responders to lumbar mechanical traction.

Purpose:: To determine: (1) the intra and inter-rater reliability of a manual unloading test of the lumbar spine and (2) the criterion referenced predictive validity for the manual unloading test.

Methods:: Ten volunteers with low back pain (LBP) underwent a manual unloading test to establish reliability. In a separate procedure, 30 consecutive patients with LBP (age 50·86±11·51) were assessed for pain in their most provocative standing position (visual analog scale (VAS) 49·53±25·52 …

Oscillatory Neural Responses Evoked By Natural Vestibular Stimuli In Humans, Steven Gale, Mario Prsa, Aaron Schurger, Annietta Gay, Aurore Paillard, Bruno Herbelin, Jean-Philippe Guyot, Christophe Lopez, Olaf Blanke

Psychology Faculty Articles and Research

While there have been numerous studies of the vestibular system in mammals, less is known about the brain mechanisms of vestibular processing in humans. In particular, of the studies that have been carried out in humans over the last 30 years, none has investigated how vestibular stimulation (VS) affects cortical oscillations. Here we recorded high-density electroencephalography (EEG) in healthy human subjects and a group of bilateral vestibular loss patients (BVPs) undergoing transient and constant-velocity passive whole body yaw rotations, focusing our analyses on the modulation of cortical oscillations in response to natural VS. The present approach overcame significant technical challenges …

How The Manipulation Of The Ras Homolog Enriched In Striatum Alters The Behavioral And Molecular Progression Of Huntington’S Disease, Franklin A. Lee

LSU New Orleans Theses and Dissertations

Huntington’s disease is an incurable, progressive neurological disorder characterized by loss of motor control, psychiatric dysfunction, and eventual dystonia leading to death. Despite the fact that this disorder is caused by a mutation in one single gene, there is no cure. The mutant Huntingtin (mHtt) protein is expressed ubiquitously throughout the brain but frank cell death is limited to the striatum. Recent work has suggested that Rhes, Ras homolog enriched in striatum, which is selectively expressed in the striatum, may play a role in Huntington’s disease neuropathology. In vitro studies have shown Rhes to be an E3 ligase for the …

Steroid Receptor Isoform Expression In Drosophila Nociceptor Neurons Is Required For Normal Dendritic Arbor And Sensitivity, Aidan L. Mcparland, Taylor L. Follansbee, Gwendolyn D. Vesenka, Alexandra E. Panaitiu, Geoffrey K. Ganter

Biology Student Publications

Steroid hormones organize many aspects of development, including that of the nervous system. Steroids also play neuromodulatory and other activational roles, including regulation of sensitivity to painful stimuli in mammals. In Drosophila, ecdysteroids are the only steroid hormones, and therefore the fly represents a simplified model system in which to explore mechanisms of steroid neuromodulation of nociception. In this report, we present evidence that ecdysteroids, acting through two isoforms of their nuclear ecdysone receptor (EcR), modulate sensitivity to noxious thermal and mechanical stimuli in the fly larva. We show that EcRA and EcRB1 are expressed by third instar larvae in …

Visual Feedback Dominates The Sense Of Agency For Brain-Machine Actions, Nathan Evans, Steven Gale, Aaron Schurger, Olaf Blanke

Psychology Faculty Articles and Research

Recent advances in neuroscience and engineering have led to the development of technologies that permit the control of external devices through real-time decoding of brain activity (brain-machine interfaces; BMI). Though the feeling of controlling bodily movements (sense of agency; SOA) has been well studied and a number of well-defined sensorimotor and cognitive mechanisms have been put forth, very little is known about the SOA for BMI-actions. Using an on-line BMI, and verifying that our subjects achieved a reasonable level of control, we sought to describe the SOA for BMI-mediated actions. Our results demonstrate that discrepancies between decoded neural activity and …