Neurology Commons^™

Inflammatory Regulation Of Cns Barriers After Traumatic Brain Injury: A Tale Directed By Interleukin-1, Colleen N. Bodnar, James B. Watson, Emma K. Higgins, Ning Quan, Adam D. Bachstetter

Neuroscience Faculty Publications

Several barriers separate the central nervous system (CNS) from the rest of the body. These barriers are essential for regulating the movement of fluid, ions, molecules, and immune cells into and out of the brain parenchyma. Each CNS barrier is unique and highly dynamic. Endothelial cells, epithelial cells, pericytes, astrocytes, and other cellular constituents each have intricate functions that are essential to sustain the brain’s health. Along with damaging neurons, a traumatic brain injury (TBI) also directly insults the CNS barrier-forming cells. Disruption to the barriers first occurs by physical damage to the cells, called the primary injury. Subsequently, during …

Optimization And Validation Of A Modified Radial-Arm Water Maze Protocol Using A Murine Model Of Mild Closed Head Traumatic Brain Injury, Teresa Macheda, Kelly N. Roberts, Josh M. Morganti, David J. Braun, Adam D. Bachstetter

Spinal Cord and Brain Injury Research Center Faculty Publications

Cognitive impairments can be a significant problem after a traumatic brain injury (TBI), which affects millions worldwide each year. There is a need for establish reproducible cognitive assays in rodents to better understand disease mechanisms and to develop therapeutic interventions towards treating TBI-induced impairments. Our goal was to validate and standardize the radial arm water maze (RAWM) test as an assay to screen for cognitive impairments caused by TBI. RAWM is a visuo-spatial learning test, originally designed for use with rats, and later adapted for mice. The present study investigates whether test procedures, such us the presence of extra-maze cues …

B Cells Migrate Into Remote Brain Areas And Support Neurogenesis And Functional Recovery After Focal Stroke In Mice, Sterling B. Ortega, Vanessa O. Torres, Sarah E. Latchney, Cody W. Whoolery, Ibrahim Z. Noorbhai, Katie Poinsatte, Uma M. Selvaraj, Monica A. Benson, Anouk J. M. Meeuwissen, Erik J. Plautz, Xiangmei Kong, Denise M. Ramirez, Apoorva D. Ajay, Julian P. Meeks, Mark P. Goldberg, Nancy L. Monson, Amelia J. Eisch, Ann M. Stowe

Neurology Faculty Publications

Lymphocytes infiltrate the stroke core and penumbra and often exacerbate cellular injury. B cells, however, are lymphocytes that do not contribute to acute pathology but can support recovery. B cell adoptive transfer to mice reduced infarct volumes 3 and 7 d after transient middle cerebral artery occlusion (tMCAo), independent of changing immune populations in recipient mice. Testing a direct neurotrophic effect, B cells cocultured with mixed cortical cells protected neurons and maintained dendritic arborization after oxygen-glucose deprivation. Whole-brain volumetric serial two-photon tomography (STPT) and a custom-developed image analysis pipeline visualized and quantified poststroke B cell diapedesis throughout the brain, including …

Rna Sequencing Of Human Peripheral Nerve In Response To Injury: Distinctive Analysis Of The Nerve Repair Pathways, Andrew S. Welleford, Jorge E. Quintero, Nader El Seblani, Eric M. Blalock, Sumedha Gunewardena, Steven M. Shapiro, Sean M. Riordan, Peter Huettl, Zain Guduru, John A. Stanford, Craig G. Van Horne, Greg A. Gerhardt

Neuroscience Faculty Publications

The development of regenerative therapies for central nervous system diseases can likely benefit from an understanding of the peripheral nervous system repair process, particularly in identifying potential gene pathways involved in human nerve repair. This study employed RNA sequencing (RNA-seq) technology to analyze the whole transcriptome profile of the human peripheral nerve in response to an injury. The distal sural nerve was exposed, completely transected, and a 1 to 2 cm section of nerve fascicles was collected for RNA-seq from six participants with Parkinson's disease, ranging in age between 53 and 70 yr. Two weeks after the initial injury, another …

Distinct Patterns Of Default Mode And Executive Control Network Circuitry Contribute To Present And Future Executive Function In Older Adults, Christopher A. Brown, Frederick A. Schmitt, Charles D. Smith, Brian T. Gold

Neuroscience Faculty Publications

Executive function (EF) performance in older adults has been linked with functional and structural profiles within the executive control network (ECN) and default mode network (DMN), white matter hyperintensities (WMH) burden and levels of Alzheimer's disease (AD) pathology. Here, we simultaneously explored the unique contributions of these factors to baseline and longitudinal EF performance in older adults. Thirty-two cognitively normal (CN) older adults underwent neuropsychological testing at baseline and annually for three years. Neuroimaging and AD pathology measures were collected at baseline. Separate linear regression models were used to determine which of these variables predicted composite EF scores at baseline …

Autologous Peripheral Nerve Grafts To The Brain For The Treatment Of Parkinson's Disease, Andrew Welleford

Theses and Dissertations--Neuroscience

Parkinson’s disease (PD) is a disorder of the nervous system that causes problems with movement (motor symptoms) as well as other problems such as mood disorders, cognitive changes, sleep disorders, constipation, pain, and other non-motor symptoms. The severity of PD symptoms worsens over time as the disease progresses, and while there are treatments for the motor and some non-motor symptoms there is no known cure for PD. Thus there is a high demand for therapies to slow the progressive neurodegeneration observed in PD. Two clinical trials at the University of Kentucky College of Medicine (NCT02369003, NCT01833364) are currently underway that …

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, …

Leukemia Inhibitory Factor Modulates The Peripheral Immune Response In A Rat Model Of Emergent Large Vessel Occlusion, Stephanie M. Davis, Lisa A. Collier, Edric D. Winford, Christopher C. Leonardo, Craig T. Ajmo Jr., Elspeth A. Foran, Timothy J. Kopper, John C. Gensel, Keith R. Pennypacker

Neurology Faculty Publications

Background: The migration of peripheral immune cells and splenocytes to the ischemic brain is one of the major causes of delayed neuroinflammation after permanent large vessel stroke. Other groups have demonstrated that leukemia inhibitory factor (LIF), a cytokine that promotes neural cell survival through upregulation of antioxidant enzymes, promotes an anti-inflammatory phenotype in several types of immune cells. The goal of this study was to determine whether LIF treatment modulates the peripheral immune response after stroke.

Methods: Young male (3 month) Sprague-Dawley rats underwent sham surgery or permanent middle cerebral artery occlusion (MCAO). Animals were administered LIF (125 μg/kg) or …

Astrocyte Activation And The Calcineurin/Nfat Pathway In Cerebrovascular Disease, Susan D. Kraner, Christopher M. Norris

Sanders-Brown Center on Aging Faculty Publications

Calcineurin (CN) is a Ca²⁺/calmodulin-dependent protein phosphatase with high abundance in nervous tissue. Though enriched in neurons, CN can become strongly induced in subsets of activated astrocytes under different pathological conditions where it interacts extensively with the nuclear factor of activated T cells (NFATs). Recent work has shown that regions of small vessel damage are associated with the upregulation of a proteolized, highly active form of CN in nearby astrocytes, suggesting a link between the CN/NFAT pathway and chronic cerebrovascular disease. In this Mini Review article, we discuss CN/NFAT signaling properties in the context of vascular disease and …

Ca2+, Astrocyte Activation And Calcineurin/Nfat Signaling In Age-Related Neurodegenerative Diseases, Pradoldej Sompol, Christopher M. Norris

Sanders-Brown Center on Aging Faculty Publications

Mounting evidence supports a fundamental role for Ca²⁺ dysregulation in astrocyte activation. Though the activated astrocyte phenotype is complex, cell-type targeting approaches have revealed a number of detrimental roles of activated astrocytes involving neuroinflammation, release of synaptotoxic factors and loss of glutamate regulation. Work from our lab and others has suggested that the Ca²⁺/calmodulin dependent protein phosphatase, calcineurin (CN), provides a critical link between Ca²⁺ dysregulation and the activated astrocyte phenotype. A proteolyzed, hyperactivated form of CN appears at high levels in activated astrocytes in both human tissue and rodent tissue around regions of amyloid and …

Myelin As An Inflammatory Mediator: Myelin Interactions With Complement, Macrophages, And Microglia In Spinal Cord Injury, Timothy J. Kopper, John C. Gensel

Spinal Cord and Brain Injury Research Center Faculty Publications

Spinal cord injury (SCI) triggers chronic intraspinal inflammation consisting of activated resident and infiltrating immune cells (especially microglia/macrophages). The environmental factors contributing to this protracted inflammation are not well understood; however, myelin lipid debris is a hallmark of SCI. Myelin is also a potent macrophage stimulus and target of complement‐mediated clearance and inflammation. The downstream effects of these neuroimmune interactions have the potential to contribute to ongoing pathology or facilitate repair. This depends in large part on whether myelin drives pathological or reparative macrophage activation states, commonly referred to as M1 (proinflammatory) or M2 (alternatively) macrophages, respectively. Here we review …

Bilateral Carotid Artery Stenosis Causes Unexpected Early Changes In Brain Extracellular Matrix And Blood-Brain Barrier Integrity In Mice, Jill M. Roberts, Michael E. Maniskas, Gregory J. Bix

Neuroscience Faculty Publications

Bilateral carotid artery stenosis (BCAS) is one experimental model of vascular dementia thought to preferentially impact brain white matter. Indeed, few studies report hippocampal and cortical pathology prior to 30 days post-stenosis; though it is unclear whether those studies examined regions outside the white matter. Since changes in the blood-brain barrier (BBB) permeability precede more overt brain pathology in various diseases, we hypothesized that changes within the BBB and/or BBB-associated extracellular matrix (ECM) could occur earlier after BCAS in the hippocampus, cortex and striatum and be a precursor of longer term pathology. Here, C57Bl/6 mice underwent BCAS or sham surgeries …

Binge Alcohol Exposure Causes Neurobehavioral Deficits And Gsk3Β Activation In The Hippocampus Of Adolescent Rats, Zhe Ji, Lin Yuan, Xiong Lu, Hanqing Ding, Jia Luo, Zun-Ji Ke

Pharmacology and Nutritional Sciences Faculty Publications

Heavy alcohol exposure causes profound damage to the adolescent brain, particularly the hippocampus, which underlie some behavioral deficits. However, the underlying molecular mechanisms remain inconclusive. The current study sought to determine whether binge alcohol exposure affects the hippocampus-related behaviors and key signaling proteins that may mediate alcohol neurotoxicity in adolescent rats. Alcohol exposure reduced the number of both NeuN-positive and doublecortin-positive cells in the hippocampus. Alcohol also induced neurodegeneration which was confirmed by ultrastructural analysis by electronic microscopy and was accompanied with the activation of microglia. Binge alcohol exposure impaired spatial learning and memory which was evaluated by the Morris …

Internal Carotid Artery Stenosis: A Novel Surgical Model For Moyamoya Syndrome, Jill M. Roberts, Michael E. Maniskas, Justin F. Fraser, Gregory J. Bix

Sanders-Brown Center on Aging Faculty Publications

Moyamoya is a cerebrovascular disorder characterized by progressive stenosis of the intracranial internal carotid arteries. There are two forms: Disease and Syndrome, with each characterized by the sub-population it affects. Moyamoya syndrome (MMS) is more prominent in adults in their 20’s-40’s, and is often associated with autoimmune diseases. Currently, there are no surgical models for inducing moyamoya syndrome, so our aim was to develop a new animal model to study this relatively unknown cerebrovascular disease. Here, we demonstrate a new surgical technique termed internal carotid artery stenosis (ICAS), to mimic MMS using micro-coils on the proximal ICA. We tested for …

Chronic Traumatic Encephalopathy-Integration Of Canonical Traumatic Brain Injury Secondary Injury Mechanisms With Tau Pathology, Jacqueline R. Kulbe, Edward D. Hall

Spinal Cord and Brain Injury Research Center Faculty Publications

In recent years, a new neurodegenerative tauopathy labeled Chronic Traumatic Encephalopathy (CTE), has been identified that is believed to be primarily a sequela of repeated mild traumatic brain injury (TBI), often referred to as concussion, that occurs in athletes participating in contact sports (e.g. boxing, football, football, rugby, soccer, ice hockey) or in military combatants, especially after blast-induced injuries. Since the identification of CTE, and its neuropathological finding of deposits of hyperphosphorylated tau protein, mechanistic attention has been on lumping the disorder together with various other non-traumatic neurodegenerative tauopathies. Indeed, brains from suspected CTE cases that have come to autopsy …

Pattern Discovery In Brain Imaging Genetics Via Scca Modeling With A Generic Non-Convex Penalty, Lei Du, Kefei Liu, Xiaohui Yao, Jingwen Yan, Shannon L. Risacher, Junwei Han, Lei Guo, Andrew J. Saykin, Li Shen, Michael W. Weiner, Paul Aisen, Ronald Petersen, Clifford R. Jack, William Jagust, John Q. Trojanowki, Arthur W. Toga, Laurel Beckett, Robert C. Green, John Morris, Leslie M. Shaw, Zaven Khachaturian, Greg Sorensen, Maria Carrillo, Lew Kuller, Marc Raichle, Steven Paul, Peter Davies, Howard Fillit, Franz Hefti, David Holtzman, Charles D. Smith, Gregory Jicha, Peter A. Hardy, Partha Sinha, Elizabeth Oates, Gary Conrad

Neurology Faculty Publications

Brain imaging genetics intends to uncover associations between genetic markers and neuroimaging quantitative traits. Sparse canonical correlation analysis (SCCA) can discover bi-multivariate associations and select relevant features, and is becoming popular in imaging genetic studies. The L1-norm function is not only convex, but also singular at the origin, which is a necessary condition for sparsity. Thus most SCCA methods impose ℓ₁-norm onto the individual feature or the structure level of features to pursuit corresponding sparsity. However, the ℓ₁-norm penalty over-penalizes large coefficients and may incurs estimation bias. A number of non-convex penalties are proposed to reduce …

A Latent Propriospinal Network Can Restore Diaphragm Function After High Cervical Spinal Cord Injury, Jared M. Cregg, Kevin A. Chu, Lydia E. Hager, Rachel S. J. Maggard, Daimen R. Stoltz, Michaela Edmond, Warren J. Alilain, Polyxeni Philippidou, Lynn T. Landmesser, Jerry Silver

Spinal Cord and Brain Injury Research Center Faculty Publications

Spinal cord injury (SCI) above cervical level 4 disrupts descending axons from the medulla that innervate phrenic motor neurons, causing permanent paralysis of the diaphragm. Using an ex vivo preparation in neonatal mice, we have identified an excitatory spinal network that can direct phrenic motor bursting in the absence of medullary input. After complete cervical SCI, blockade of fast inhibitory synaptic transmission caused spontaneous, bilaterally coordinated phrenic bursting. Here, spinal cord glutamatergic neurons were both sufficient and necessary for the induction of phrenic bursts. Direct stimulation of phrenic motor neurons was insufficient to evoke burst activity. Transection and pharmacological manipulations …

Targeting Mitochondrial Dysfunction In Cns Injury Using Methylene Blue; Still A Magic Bullet?, Hemendra J. Vekaria, Lora Talley Watts, Ai-Ling Lin, Patrick G. Sullivan

Spinal Cord and Brain Injury Research Center Faculty Publications

Complex, multi-factorial secondary injury cascades are initiated following traumatic brain injury, which makes this a difficult disease to treat. The secondary injury cascades following the primary mechanical tissue damage, are likely where effective therapeutic interventions may be targeted. One promising therapeutic target following brain injury are mitochondria. Mitochondria are complex organelles found within the cell, which act as powerhouses within all cells by supplying ATP. These organelles are also necessary for calcium cycling, redox signaling and play a major role in the initiation of cell death pathways. When mitochondria become dysfunctional, there is a tendency for the cell to loose …

Acute Treatment With Doxorubicin Affects Glutamate Neurotransmission In The Mouse Frontal Cortex And Hippocampus, Theresa Currier Thomas, Joshua A. Beitchman, Francois Pomerleau, Teresa Noel, Paiboon Jungsuwadee, D. Allan Butterfield, Daret K. St. Clair, Mary Vore, Greg A. Gerhardt

Spinal Cord and Brain Injury Research Center Faculty Publications

Doxorubicin (DOX) is a potent chemotherapeutic agent known to cause acute and long-term cognitive impairments in cancer patients. Cognitive function is presumed to be primarily mediated by neuronal circuitry in the frontal cortex (FC) and hippocampus, where glutamate is the primary excitatory neurotransmitter. Mice treated with DOX (25 mg/kg i.p.) were subjected to in vivo recordings under urethane anesthesia at 24h post-DOX injection or 5 consecutive days of cognitive testing (Morris Water Maze; MWM). Using novel glutamate-selective microelectrode arrays, amperometric recordings measured parameters of extracellular glutamate clearance and potassium-evoked release of glutamate within the medial FC and dentate gyrus (DG) …

Linking Kindling To Increased Glutamate Release In The Dentate Gyrus Of The Hippocampus Through The Stxbp5/Tomosyn-1 Gene, Seth R. Batten, Elena A. Matveeva, Sidney W. Whiteheart, Thomas C. Vanaman, Greg A. Gerhardt, John T. Slevin

Psychology Faculty Publications

Introduction: In kindling, repeated electrical stimulation of certain brain areas causes progressive and permanent intensification of epileptiform activity resulting in generalized seizures. We focused on the role(s) of glutamate and a negative regulator of glutamate release, STXBP5/tomosyn-1, in kindling.

Methods: Stimulating electrodes were implanted in the amygdala and progression to two successive Racine stage 5 seizures was measured in wild-type and STXBP5/tomosyn-1^−/− (Tom^−/−) animals. Glutamate release measurements were performed in distinct brain regions using a glutamate-selective microelectrode array (MEA).

Results: Naïve Tom^−/− mice had significant increases in KCl-evoked glutamate release compared to naïve wild type as …

Drug-Resistant Epilepsy: Multiple Hypotheses, Few Answers, Fei Tang, Anika M. S. Hartz, Björn Bauer

Pharmaceutical Sciences Faculty Publications

Epilepsy is a common neurological disorder that affects over 70 million people worldwide. Despite the recent introduction of new antiseizure drugs (ASDs), about one-third of patients with epilepsy have seizures refractory to pharmacotherapy. Early identification of patients who will become refractory to ASDs could help direct such patients to appropriate non-pharmacological treatment, but the complexity in the temporal patterns of epilepsy could make such identification difficult. The target hypothesis and transporter hypothesis are the most cited theories trying to explain refractory epilepsy, but neither theory alone fully explains the neurobiological basis of pharmacoresistance. This review summarizes evidence for and against …

Carisbamate Blockade Of T-Type Voltage-Gated Calcium Channels, Do Young Kim, Fang-Xiong Zhang, Stan T. Nakanishi, Timothy Mettler, Ik-Hyun Cho, Younghee Ahn, Florian Hiess, Lina Chen, Patrick G. Sullivan, S. R. Wayne Chen, Gerald W. Zamponi, Jong M. Rho

Spinal Cord and Brain Injury Research Center Faculty Publications

Objectives

Carisbamate (CRS) is a novel monocarbamate compound that possesses antiseizure and neuroprotective properties. However, the mechanisms underlying these actions remain unclear. Here, we tested both direct and indirect effects of CRS on several cellular systems that regulate intracellular calcium concentration [Ca²⁺]_i.

Methods

We used a combination of cellular electrophysiologic techniques, as well as cell viability, Store Overload‐Induced Calcium Release (SOICR), and mitochondrial functional assays to determine whether CRS might affect [Ca²⁺]_i levels through actions on the endoplasmic reticulum (ER), mitochondria, and/or T‐type voltage‐gated Ca²⁺ channels.

Results

In CA3 pyramidal neurons, kainic …

GabaB Receptor Attenuation Of GabaA Currents In Neurons Of The Mammalian Central Nervous System, Wen Shen, Changlong Nan, Peter T. Nelson, Harris Ripps, Malcolm M. Slaughter

Pathology and Laboratory Medicine Faculty Publications

Ionotropic receptors are tightly regulated by second messenger systems and are often present along with their metabotropic counterparts on a neuron's plasma membrane. This leads to the hypothesis that the two receptor subtypes can interact, and indeed this has been observed in excitatory glutamate and inhibitory GABA receptors. In both systems the metabotropic pathway augments the ionotropic receptor response. However, we have found that the metabotropic GABA_B receptor can suppress the ionotropic GABA_A receptor current, in both the in vitro mouse retina and in human amygdala membrane fractions. Expression of amygdala membrane microdomains in Xenopus oocytes by microtransplantation …

Correcting The Trajectory Of Stroke Therapeutic Research, Keith R. Pennypacker, Gregory J. Bix, Justin F. Fraser

Neurology Faculty Publications

No abstract provided.

The Default Mode Network And Executive Function: Influence Of Age, White Matter Connectivity, And Alzheimer’S Pathology, Christopher A. Brown

Theses and Dissertations--Neuroscience

The default mode network (DMN) consists of a set of interconnected brain regions supporting autobiographical memory, our concept of the self, and the internal monologue. These processes must be maintained at all times and consume the highest amount of the brain’s energy during its baseline state. However, when faced with an active, externally-directed cognitive task, the DMN shows a small, but significant, decrease in activity. The reduction in DMN activity during the performance of an active, externally-directed task compared to a baseline state is termed task-induced deactivation (TID), which is thought to ‘free-up’ resources required to respond to external demands. …

Proceedings Of The Third Annual Deep Brain Stimulation Think Tank: A Review Of Emerging Issues And Technologies, P. Justin Rossi, Aysegul Gunduz, Jack Judy, Linda Wilson, Andre Machado, James J Giordano, W. Jeff Elias, Marvin A. Rossi, Christopher L. Butson, Michael D. Fox, Cameron C. Mcintyre, Nader Pouratian, Nicole C. Swann, Coralie De Hemptinne, Robert E. Gross, Howard J. Chizeck, Michele Tagliati, Andres M. Lozano, Wayne Goodman, Jean-Philippe Langevin, Ron L. Alterman, Umer Akbar, Greg A. Gerhardt, Warren M. Grill, Mark Hallett, Todd Herrington, Jeffrey Herron, Craig Van Horne, Brian H. Kopell, Anthony E. Lang

Neuroscience Faculty Publications

The proceedings of the 3rd Annual Deep Brain Stimulation Think Tank summarize the most contemporary clinical, electrophysiological, imaging, and computational work on DBS for the treatment of neurological and neuropsychiatric disease. Significant innovations of the past year are emphasized. The Think Tank's contributors represent a unique multidisciplinary ensemble of expert neurologists, neurosurgeons, neuropsychologists, psychiatrists, scientists, engineers, and members of industry. Presentations and discussions covered a broad range of topics, including policy and advocacy considerations for the future of DBS, connectomic approaches to DBS targeting, developments in electrophysiology and related strides toward responsive DBS systems, and recent developments in sensor and …

Chronic Systemic Immune Dysfunction In African-Americans With Small Vessel-Type Ischemic Stroke, Candice M. Brown, Cheryl D. Bushnell, Gregory P. Samsa, Larry B. Goldstein, Carol A. Colton

Neurology Faculty Publications

The incidence of small vessel-type (lacunar) ischemic strokes is greater in African-Americans compared to whites. The chronic inflammatory changes that result from lacunar stroke are poorly understood. To elucidate these changes, we measured serum inflammatory and thrombotic biomarkers in African-Americans at least 6 weeks post-stroke compared to control individuals. Cases were African-Americans with lacunar stroke (n = 30), and controls were age-matched African-Americans with no history of stroke or other major neurologic disease (n = 37). Blood was obtained > 6 weeks post-stroke and was analyzed for inflammatory biomarkers. Freshly isolated peripheral blood mononuclear cells were stimulated with lipopolysaccharide …

Immunotherapy In Combination With Behavioral Enrichment In A Canine Model Of Aging, Paulina R. Davis

Theses and Dissertations--Pharmacology and Nutritional Sciences

Alzheimer’s disease (AD) is characterized by cognitive decline and hallmark neuropathology, including β-amyloid (Aβ). Therapeutic strategies for AD are focusing on reducing Aβ. Canines develop Aβ neuropathology and cognitive decline with age similar to AD patients. In previous studies, immunization with Aβ1-42 (VAC) in aged canines decreased brain Aβ but did not improve cognition. Behavioral enrichment (ENR) improved cognition without reducing brain Aβ. We hypothesized that VAC combined with ENR would provide cognitive benefits and reduce Aβ neuropathology, as compared individual VAC and ENR treatments. Aged beagles were placed into groups: control, VAC with fibrillar Aβ1-42, ENR, and combination treatment …

Lifelong Bilingualism Maintains Neural Efficiency For Cognitive Control In Aging, Brian T. Gold, Chobok Kim, Nathan F. Johnson, Richard J. Kryscio, Charles D. Smith

Neuroscience Faculty Publications

Recent behavioral data have shown that lifelong bilingualism can maintain youthful cognitive control abilities in aging. Here, we provide the first direct evidence of a neural basis for the bilingual cognitive control boost in aging. Two experiments were conducted, using a perceptual task-switching paradigm, including a total of 110 participants. In Experiment 1, older adult bilinguals showed better perceptual switching performance than their monolingual peers. In Experiment 2, younger and older adult monolinguals and bilinguals completed the same perceptual task-switching experiment while functional magnetic resonance imaging (fMRI) was performed. Typical age-related performance reductions and fMRI activation increases were observed. However, …

Multimodal Imaging Evidence For Axonal And Myelin Deterioration In Amnestic Mild Cognitive Impairment, Brian T. Gold, Yang Jiang, David K. Powell, Charles D. Smith

Neuroscience Faculty Publications

White matter (WM) microstructural declines have been demonstrated in Alzheimer's disease and amnestic mild cognitive impairment (aMCI). However, the pattern of WM microstructural changes in aMCI after controlling for WM atrophy is unknown. Here, we address this issue through joint consideration of aMCI alterations in fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity, as well as macrostructural volume in WM and gray matter compartments. Participants were 18 individuals with aMCI and 24 healthy seniors. Voxelwise analyses of diffusion tensor imaging data was carried out using tract-based spatial statistics (TBSS) and voxelwise analyses of high-resolution structural data was conducted using …