Neurology Commons^™

Nucleus Accumbens Core Single Cell Ensembles Bidirectionally Respond To Experienced Versus Observed Aversive Events, Oyku Dinckol, Noah Harris Wenger, Jennifer E Zachry, Munir Gunes Kutlu

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Fear learning is a critical feature of survival skills among mammals. In rodents, fear learning manifests itself through direct experience of the aversive event or social transmission of aversive stimuli such as observing and acting on conspecifics' distress. The neuronal network underlying the social transmission of information largely overlaps with the brain regions that mediate behavioral responses to aversive and rewarding stimuli. In this study, we recorded single cell activity patterns of nucleus accumbens (NAc) core neurons using in vivo optical imaging of calcium transients via miniature scopes. This cutting-edge imaging methodology not only allows us to record activity patterns …

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 …

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 …

Linkage, Whole Genome Sequence, And Biological Data Implicate Variants In Rab10 In Alzheimer's Disease Resilience., Perry G Ridge, Celeste M Karch, Simon Hsu, Ivan Arano, Craig C Teerlink, Mark T W Ebbert, Josue D Gonzalez Murcia, James M Farnham, Anna R Damato, Mariet Allen, Xue Wang, Oscar Harari, Victoria M Fernandez, Rita Guerreiro, Jose Bras, John Hardy, Ronald Munger, Maria Norton, Celeste Sassi, Andrew Singleton, Steven G Younkin, Dennis W Dickson, Todd E Golde, Nathan D Price, Nilüfer Ertekin-Taner, Carlos Cruchaga, Alison M Goate, Christopher Corcoran, Joann Tschanz, Lisa A Cannon-Albright, John S K Kauwe

Articles, Abstracts, and Reports

BACKGROUND: While age and the APOE ε4 allele are major risk factors for Alzheimer's disease (AD), a small percentage of individuals with these risk factors exhibit AD resilience by living well beyond 75 years of age without any clinical symptoms of cognitive decline.

METHODS: We used over 200 "AD resilient" individuals and an innovative, pedigree-based approach to identify genetic variants that segregate with AD resilience. First, we performed linkage analyses in pedigrees with resilient individuals and a statistical excess of AD deaths. Second, we used whole genome sequences to identify candidate SNPs in significant linkage regions. Third, we replicated SNPs …

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 …

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) …

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 …

High Resolution Time-Course Mapping Of Early Transcriptomic, Molecular And Cellular Phenotypes In Huntington's Disease Cag Knock-In Mice Across Multiple Genetic Backgrounds., Seth A Ament, Jocelynn R Pearl, Andrea Grindeland, Jason St Claire, John C Earls, Marina Kovalenko, Tammy Gillis, Jayalakshmi Mysore, James F Gusella, Jong-Min Lee, Seung Kwak, David Howland, Min Young Lee, David Baxter, Kelsey Scherler, Kai Wang, Donald Geman, Jeffrey B Carroll, Marcy E Macdonald, George Carlson, Vanessa C Wheeler, Nathan D Price, Leroy Hood

Articles, Abstracts, and Reports

Huntington's disease is a dominantly inherited neurodegenerative disease caused by the expansion of a CAG repeat in the HTT gene. In addition to the length of the CAG expansion, factors such as genetic background have been shown to contribute to the age at onset of neurological symptoms. A central challenge in understanding the disease progression that leads from the HD mutation to massive cell death in the striatum is the ability to characterize the subtle and early functional consequences of the CAG expansion longitudinally. We used dense time course sampling between 4 and 20 postnatal weeks to characterize early transcriptomic, …

Peripheral Huntingtin Silencing Does Not Ameliorate Central Signs Of Disease In The B6.Httq111/+ Mouse Model Of Huntington's Disease., Sydney R Coffey, Robert M Bragg, Shawn Minnig, Seth A Ament, Jeffrey P Cantle, Anne Glickenhaus, Daniel Shelnut, José M Carrillo, Dominic D Shuttleworth, Julie-Anne Rodier, Kimihiro Noguchi, C Frank Bennett, Nathan D Price, Holly B Kordasiewicz, Jeffrey B Carroll

Articles, Abstracts, and Reports

Huntington's disease (HD) is an autosomal dominant neurodegenerative disease whose predominant neuropathological signature is the selective loss of medium spiny neurons in the striatum. Despite this selective neuropathology, the mutant protein (huntingtin) is found in virtually every cell so far studied, and, consequently, phenotypes are observed in a wide range of organ systems both inside and outside the central nervous system. We, and others, have suggested that peripheral dysfunction could contribute to the rate of progression of striatal phenotypes of HD. To test this hypothesis, we lowered levels of huntingtin by treating mice with antisense oligonucleotides (ASOs) targeting the murine …

Repeated Closed Head Injury In Mice Results In Sustained Motor And Memory Deficits And Chronic Cellular Changes, Amanda Nicholle Bolton Hall, Binoy Joseph, Jennifer M. Brelsfoard, Kathryn E. Saatman

Spinal Cord and Brain Injury Research Center Faculty Publications

Millions of mild traumatic brain injuries (TBIs) occur every year in the United States, with many people subject to multiple head injuries that can lead to chronic behavioral dysfunction. We previously reported that mild TBI induced using closed head injuries (CHI) repeated at 24h intervals produced more acute neuron death and glial reactivity than a single CHI, and increasing the length of time between injuries to 48h reduced the cumulative acute effects of repeated CHI. To determine whether repeated CHI is associated with behavioral dysfunction or persistent cellular damage, mice receiving either five CHI at 24h intervals, five CHI at …

Mechanical Conflict System: A Novel Operant Method For The Assessment Of Nociceptive Behavior, Steven E. Harte, Jessica B. Meyers, Renee R. Donahue, Bradley K. Taylor, Thomas J. Morrow

Physiology Faculty Publications

A new operant test for preclinical pain research, termed the Mechanical Conflict System (MCS), is presented. Rats were given a choice either to remain in a brightly lit compartment or to escape to a dark compartment by crossing an array of height-adjustable nociceptive probes. Latency to escape the light compartment was evaluated with varying probe heights (0, .5, 1, 2, 3, and 4 mm above compartment floor) in rats with neuropathic pain induced by constriction nerve injury (CCI) and in naive control rats. Escape responses in CCI rats were assessed following intraperitoneal administration of pregabalin (10 and 30 mg/kg), morphine …

Dietary Supplementation With Organoselenium Accelerates Recovery Of Bladder Expression, But Does Not Improve Locomotor Function, Following Spinal Cord Injury, Carolyn A. Meyer, Ranjana Singh, Mackenzie T. Jones, Chen-Guang Yu, Ronan F. Power, James W. Geddes

Spinal Cord and Brain Injury Research Center Faculty Publications

Selenium is an essential element required for activity of several antioxidant enzymes, including glutathione peroxidase. Because of the critical role of the antioxidant system in responding to traumatic events, we hypothesized that dietary selenium supplementation would enhance neuroprotection in a rodent model of spinal cord injury. Rats were maintained on either a control or selenium-enriched diet prior to, and following, injury. Dietary selenium supplementation, provided as selenized yeast added to normal rat chow, resulted in a doubling of selenium levels in the spinal cord. Dietary selenium reduced the time required for recovery of bladder function following thoracic spinal cord injury. …

The Role Of Capillaries In The Lesser Ailments Of Old Age And In Alzheimer's Disease And Vascular Dementia: The Potential Of Pro-Therapeutic Angiogenesis, Charles T. Ambrose

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Apart from chronic diseases (arthritis, diabetes, etc.), old age is generally characterized by three lesser ailments: muscle weakness, minor memory lapses, and cold intolerance. This trio of complaints may have a common, underlying cause, namely, the age-associated reduced microcirculation in muscles, brain, skin, and elsewhere in the body. The Angiogenesis Hypothesis proposes that old age is in part a deficiency disease due to the decline in angiogenic (AG) factors, resulting in a reduced capillary density (CD) throughout the body. Over fifty published papers document waning levels of AG factors and/or decreased CD in various organ systems of aged animals and …

Muscle Weakness During Aging: A Deficiency State Involving Declining Angiogenesis, Charles T. Ambrose

Microbiology, Immunology, and Molecular Genetics Faculty Publications

This essay begins by proposing that muscle weakness of old age from sarcopenia is due in large part to reduced capillary density in the muscles, as documented in 9 reports of aged persons and animals. Capillary density (CD) is determined by local levels of various angiogenic factors, which also decline in muscles with aging, as reported in 7 studies of old persons and animals. There are also numerous reports of reduced CD in the aged brain and other studies showing reduced CD in the kidney and heart of aged animals. Thus a waning angiogenesis throughout the body may be …

A Therapeutic Approach For Senile Dementias: Neuroangiogenesis, Charles T. Ambrose

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Alzheimer's disease (AD) and related senile dementias (SDs) represent a growing medical and economic crisis in this country. Apart from cautioning persons about risk factors, no practical, effective therapy is currently available. Much of the recent research in AD has been based on the amyloid cascade theory. Another approach assumes a vascular basis for SDs. This paper presents evidence from a score of studies that cerebral capillary density (CCD) declines during old age in animals and people as well as in AD. Neuroangiogenic (NAG) factors initiate and maintain capillaries in the brain. Thus a waning level of these factors and …

Short Duration Waveforms Recorded Extracellularly From Freely Moving Rats Are Representative Of Axonal Activity, Ashlee A. Robbins, Steven E. Fox, Gregory L. Holmes, Rod C. Scott, Jeremy M. Barry

Dartmouth Scholarship

While extracellular somatic action potentials from freely moving rats have been well characterized, axonal activity has not. We report direct extracellular tetrode recordings of putative axons whose principal feature is a short duration waveform (SDW) with an average peak-trough length less than 179 μs. While SDW recordings using tetrodes have previously been treated as questionable or classified as cells, we hypothesize that they are representative of axonal activity. These waveforms have significantly shorter duration than somatic action potentials, are triphasic and are therefore similar to classic descriptions of microelectrode recordings in white matter and of in vitro action potential propagation …