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white matter tract disruption in spinal cord

Daniel Nunes, Tomás L Cruz, Sune N Jespersen, Noam Shemesh
White Matter (WM) microstructures, such as axonal density and average diameter, are crucial to the normal function of the Central Nervous System (CNS) as they are closely related with axonal conduction velocities. Conversely, disruptions of these microstructural features may result in severe neurological deficits, suggesting that their noninvasive mapping could be an important step towards diagnosing and following pathophysiology. Whereas diffusion based MRI methods have been proposed to map these features, they typically entail the application of powerful gradients, which are rarely available in the clinic, or extremely long acquisition schemes to extract information from parameter-intensive models...
February 28, 2017: Journal of Magnetic Resonance
Peng Sun, Rory K J Murphy, Paul Gamble, Ajit George, Sheng-Kwei Song, Wilson Z Ray
Promising treatments are being developed to promote functional recovery after spinal cord injury (SCI). Magnetic resonance imaging, specifically Diffusion Tensor Imaging (DTI) has been shown to non-invasively measure both axonal and myelin integrity following traumatic brain and SCI. A novel data-driven model-selection algorithm known as Diffusion Basis Spectrum Imaging (DBSI) has been proposed to more accurately delineate white matter injury. The objective of this study was to investigate whether DTI/DBSI changes that extend to level of the cerebral peduncle and internal capsule following a SCI could be correlated with clinical function...
February 17, 2017: Brain Sciences
Byron A Kakulas, Cahyono Kaelan
An appreciation of the neuropathology of human spinal cord injury (SCI) is a basic requirement for all concerned with the medical treatment of patients with SCI as well as for the many neuroscientists devoted to finding a "cure". An understanding of the neuropathology of SCI is a necessary guide to those concerned at all levels of treatment, whether they are doctors or other health professionals. The underlying changes in the spinal cord are especially relevant to the restorative neurology (RN) of SCI. The new discipline of RN seeks to enhance the function of residual spinal cord elements which have survived the injury and so improve the patient's rehabilitative status...
February 2015: Clinical Neurology and Neurosurgery
Fabien Rech, Guillaume Herbet, Sylvie Moritz-Gasser, Hugues Duffau
OBJECTIVES: Cortical areas involved in bimanual coordination have been regularly studied by functional neuroimaging and electroencephalography. However, the subcortical connectivity underlying this complex function has received less attention. Here, we used the technique of direct electrostimulation in awake patients who underwent surgery for brain glioma, with the goal to investigate the white matter pathways subserving bimanual coordination. EXPERIMENTAL DESIGN: Eight patients were operated under local anesthesia for a frontal low-grade glioma...
July 2014: Human Brain Mapping
J-S Kang, J C Klein, S Baudrexel, R Deichmann, D Nolte, R Hilker
Spinocerebellar ataxia type 3 (SCA3) is the most frequent inherited cerebellar ataxia in Europe, the US and Japan, leading to disability and death through motor complications. Although the affected protein ataxin-3 is found ubiquitously in the brain, grey matter atrophy is predominant in the cerebellum and the brainstem. White matter pathology is generally less severe and thought to occur in the brainstem, spinal cord, and cerebellar white matter. Here, we investigated both grey and white matter pathology in a group of 12 SCA3 patients and matched controls...
February 2014: Journal of Neurology
Arsen S Hunanyan, Hayk A Petrosyan, Valentina Alessi, Victor L Arvanian
Transmission through descending pathways to lumbar motoneurons, although important for voluntary walking in humans and rats, has not been fully understood at the cellular level in contusion models. Major descending pathways innervating lumbar motoneurons include those at corticospinal tract (CST) and ventrolateral funiculus (VLF). We examined transmission and plasticity at synaptic pathways from dorsal (d)CST and VLF to individual motoneurons located in ventral horn and interneurons located in dorsomedial gray matter at lumbar segments after thoracic chronic contusion in adult anesthetized rats...
October 2013: Journal of Neurophysiology
Brett W Fling, Rajal G Cohen, Martina Mancini, John G Nutt, Damian A Fair, Fay B Horak
Freezing of gait is one of the most debilitating symptoms in Parkinson's disease as it causes falls and reduces mobility and quality of life. The pedunculopontine nucleus is one of the major nuclei of the mesencephalic locomotor region and has neurons related to anticipatory postural adjustments preceding step initiation as well as to the step itself, thus it may be critical for coupling posture and gait to avoid freezing. Because freezing of gait and postural impairments have been related to frontal lesions and frontal dysfunction such as executive function, we hypothesized that freezing is associated with disrupted connectivity between midbrain locomotor regions and medial frontal cortex...
August 2013: Brain: a Journal of Neurology
Spyridon K Karadimas, Eun Su Moon, Wen-Ru Yu, Kajana Satkunendrarajah, Joannis K Kallitsis, Georgios Gatzounis, Michael G Fehlings
Cervical spondylotic myelopathy (CSM) is the most common form of spinal cord impairment in adults. However critical gaps in our knowledge of the pathobiology of this disease have limited therapeutic advances. To facilitate progress in the field of regenerative medicine for CSM, we have developed a unique, clinically relevant model of CSM in rats. To model CSM, a piece of synthetic aromatic polyether, to promote local calcification, was implanted microsurgically under the C6 lamina in rats. We included a sham group in which the material was removed 30s after the implantation...
June 2013: Neurobiology of Disease
Elizabeth B Hutchinson, Aleksey S Sobakin, Mary E Meyerand, Marlowe Eldridge, Peter Ferrazzano
In order to develop more sensitive imaging tools for clinical use and basic research of spinal decompression sickness (DCS), we used diffusion tensor MRI (DTI) validated by histology to assess DCS-related tissue injury in sheep spinal cords. DTI is based on the measurement of water diffusion indices, including fractional anisotropy (FA) and mean diffusion (MD) to detect tissue microstructural abnormalities. In this study, we measured FA and MD in white and gray matter spinal cord regions in samples taken from sheep following hyperbaric exposure to 60-132 fsw and 0-180 minutes of oxygen pre-breathing treatment before rapid decompression...
January 2013: Undersea & Hyperbaric Medicine: Journal of the Undersea and Hyperbaric Medical Society, Inc
Shanmughanathan Rajasekaran, Rishi M Kanna, Ajoy P Shetty, Venkatachalam Ilayaraja
BACKGROUND CONTEXT: Signal intensity changes observed in magnetic resonance imaging (MRI) do not reveal the actual severity of axonal damage incurred in spinal cord injuries. Diffusion tensor imaging (DTI) is an imaging technique with a potential to track individual nerve fiber tracts. PURPOSE: We explored the use of DTI in quantifying the extent of spinal cord injury and differentiated areas of injured spinal cord from regions with intact fiber tracts in a cadaveric animal model...
December 2012: Spine Journal: Official Journal of the North American Spine Society
Patrick Freund, Claudia A Wheeler-Kingshott, Zoltan Nagy, Nikos Gorgoraptis, Nikolaus Weiskopf, Karl Friston, Alan J Thompson, Chloe Hutton
BACKGROUND: Traumatic spinal cord injury (SCI) leads to disruption of axonal architecture and macroscopic tissue loss with impaired information flow between the brain and spinal cord-the presumed basis of ensuing clinical impairment. OBJECTIVE: The authors used a clinically viable, multimodal MRI protocol to quantify the axonal integrity of the cranial corticospinal tract (CST) and to establish how microstructural white matter changes in the CST are related to cross-sectional spinal cord area and cortical reorganisation of the sensorimotor system in subjects with traumatic SCI...
June 2012: Journal of Neurology, Neurosurgery, and Psychiatry
Bin Xing, Hui Li, Hongyu Wang, Dhriti Mukhopadhyay, Daniel Fisher, Christopher J Gilpin, Shuxin Li
Nonsteroidal anti-inflammatory drugs (NSAIDs) are extensively used to relieve pain and inflammation in humans via cyclooxygenase inhibition. Our recent research suggests that certain NSAIDs including ibuprofen suppress intracellular RhoA signal and improve significant axonal growth and functional recovery following axonal injury in the CNS. Several NSAIDs have been shown to reduce generation of amyloid-beta42 peptide via inactivation of RhoA signal, supporting potent RhoA-repressing function of selected NSAIDs...
October 2011: Experimental Neurology
Kyung Hee Lee, Un Jeng Kim, Yong Gou Park, Ran Won, Hyejung Lee, Bae Hwan Lee
Optical imaging techniques have made it possible to monitor neural activity and to determine its spatiotemporal patterns. Traumatic spinal cord injury (SCI) results in both the death of gray matter neurons and the disruption of ascending and descending white matter tracts at the injury site, leading to the loss of motor and sensory functions. In this study, we monitored and compared cortical responses to the stimulation of sensory tracts in normal control and spinal-cord-injured rats using an optical imaging technique based on a voltage-sensitive dye (VSD)...
May 2011: Journal of Neurotrauma
Matthew J Farrar, Frank W Wise, Joseph R Fetcho, Chris B Schaffer
Loss of myelin in the central nervous system (CNS) leads to debilitating neurological deficits. High-resolution optical imaging of myelin in the CNS of animal models is limited by a lack of in vivo myelin labeling strategies. We demonstrated that third harmonic generation (THG) microscopy-a coherent, nonlinear, dye-free imaging modality-provides micrometer resolution imaging of myelin in the mouse CNS. In fixed tissue, we found that THG signals arose from white matter tracts and were colocalized with two-photon excited fluorescence (2PEF) from a myelin-specific dye...
March 2, 2011: Biophysical Journal
Zhen-Hua Shi, Guangjun Nie, Xiang-Lin Duan, Tracey Rouault, Wen-Shuang Wu, Bo Ning, Nan Zhang, Yan-Zhong Chang, Bao-Lu Zhao
Neuronal iron homeostasis disruption and oxidative stress are closely related to the pathogenesis of Parkinson's disease (PD). Adult iron-regulatory protein 2 knockout (Ireb2(-/-)) mice develop iron accumulation in white matter tracts and nuclei in different brain area and display severe neurodegeneration in Purkinje cells of the cerebrum. Mitochondrial ferritin (MtFt), a newly discovered ferritin, specifically expresses in high energy-consuming cells, including neurons of brain and spinal cord. Interestingly, the decreased expression of MtFt in cerebrum, but not in striatum, matches the differential neurodegeneration pattern in these Ireb2(-/-) mice...
September 15, 2010: Antioxidants & Redox Signaling
Jeremy D Schmahmann, Eric E Smith, Florian S Eichler, Christopher M Filley
Lesions of the cerebral white matter (WM) result in focal neurobehavioral syndromes, neuropsychiatric phenomena, and dementia. The cerebral WM contains fiber pathways that convey axons linking cerebral cortical areas with each other and with subcortical structures, facilitating the distributed neural circuits that subserve sensorimotor function, intellect, and emotion. Recent neuroanatomical investigations reveal that these neural circuits are topographically linked by five groupings of fiber tracts emanating from every neocortical area: (1) cortico-cortical association fibers; (2) corticostriatal fibers; (3) commissural fibers; and cortico-subcortical pathways to (4) thalamus and (5) pontocerebellar system, brain stem, and/or spinal cord...
October 2008: Annals of the New York Academy of Sciences
Saurabh Guleria, Rakesh K Gupta, Sona Saksena, Anil Chandra, R N Srivastava, Mazhar Husain, Ramkishore Rathore, Ponnada A Narayana
Diffusion tensor imaging (DTI) has the potential to reveal disruption of white matter microstructure in chronically injured spinal cords. We quantified fractional anisotropy (FA) and mean diffusivity (MD) to demonstrate retrograde Wallerian degeneration (WD) of cranial corticospinal tract (CST) in cervical spinal cord injury (SCI). Twenty-two patients with complete cervical SCI in the chronic stage were studied with DTI along with 13 healthy controls. Mean FA and MD values were computed for midbrain, pons, medulla, posterior limb of internal capsule, and corona radiata...
August 1, 2008: Journal of Neuroscience Research
Anthony M Choo, Jie Liu, Clarrie K Lam, Marcel Dvorak, Wolfram Tetzlaff, Thomas R Oxland
OBJECT: In experimental models of spinal cord injury (SCI) researchers have typically focused on contusion and transection injuries. Clinically, however, other injury mechanisms such as fracture-dislocation and distraction also frequently occur. The objective of the present study was to compare the primary damage in three clinically relevant animal models of SCI. METHODS: Contusion, fracture-dislocation, and flexion-distraction animal models of SCI were developed...
March 2007: Journal of Neurosurgery. Spine
Eric D Schwartz, Jeffrey Duda, Jed S Shumsky, Emily T Cooper, James Gee
Diffusion tensor magnetic resonance imaging (DTI) provides data concerning water diffusion in the spinal cord, from which white matter tracts may be inferred, and connectivity between spinal cord segments may be determined. We evaluated this potential application by imaging spinal cords from normal adult rats and rats that received cervical lateral funiculotomies, disrupting the rubrospinal tract (RST). Vitrogen and fibroblasts were transplanted into the surgical lesion at time of injury in order to fill the cavity...
December 2005: Journal of Neurotrauma
W Gomes-Leal, D J Corkill, C W Picanço-Diniz
The mechanisms of white matter (WM) damage during secondary degeneration are a fundamental issue in the pathophysiology of central nervous system (CNS) diseases. Our main goal was to describe the pattern of an acute inflammatory response and secondary damage to axons in different WM tracts of acutely injured rat spinal cord. Adult rats were deeply anesthetized and injected with 20 nmol of NMDA into the spinal cord ventral horn on T7. Animals were perfused after survival times of 1 day, 3 days and 7 days. Ten micrometer sections were submitted to immunocytochemical analysis for activated macrophages/microglia, neutrophils and damaged axons...
December 20, 2005: Brain Research
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