Dissertations / Theses on the topic 'Corticospinal tract'
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Kathe, Claudia. "Improving mobility after corticospinal tract injury." Thesis, King's College London (University of London), 2016. https://kclpure.kcl.ac.uk/portal/en/theses/improving-mobility-after-corticospinal-tract-injury(ca3be9d6-a198-42ef-bb32-ab28a59e273c).html.
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The corticospinal tract is one of the major motor tracts in the spinal cord. Traumatic injury to it through spinal cord injury or stroke results in loss of dexterity, coordinated locomotion and fine motor function. With time the spinal circuitry adapts, which may result in spasticity. This thesis is a characterisation of a corticospinal tract injury in a rodent model and evaluates three different treatments, which aim to improve functional recovery post-injury. The first result chapter describes the unilateral pyramidotomy surgery, which lesions the corticospinal tract at medullary level in the brainstem. I performed different behavioural tests assessing motor and sensory function, which revealed sustained deficits. Furthermore, I developed 3 different neurophysiology protocols, which assess functional neurophysiological recovery following sprouting of the uninjured corticospinal tract. I found direct cortical stimulation in combination with EMG recordings from a forelimb muscle (the extensor carpii radialis) is most suitable for longitudinal neurophysiological monitoring of corticospinal tract plasticity. Two of the result chapters evaluate two different gene therapies, which modulate intrinsic neuronal properties. In each, we transduced the motor cortex with a regeneration-associated gene. First, we overexpressed protein tyrosine phosphatase, non-receptor type 2, which also may act as a transcription factor. I performed a unilateral pyramidotomy lesion and treated the unaffected corticospinal tract to increase sprouting. The second gene therapy we tested was with ribonuclease inhibitor 1, which inhibits ribonucleases that are degrading RNA. I performed a cervical lateral hemisection and treated the lesioned corticospinal tract to increase regeneration. To assess if these treatments were effective, I performed behavioural testing, neurophysiology and immunohistochemistry. Both treatments, with Ptpn2 and RNH1, improved functional recovery, neurophysiological outcomes and increased plasticity. In the last result chapter, I performed a bilateral corticospinal tract lesion/pyramidotomy, which causes spasticity through spinal circuitry maladaptations. First, I characterised spasticity behaviourally by developing a new open-field scoring system, neurophysiologically with two different preparations assessing reflex pathways and anatomically by looking at excitatory and inhibitory spinal networks. Next, I treated these rats with intramuscular neurotrophin-3, which is developmentally important for patterning of spinal reflex pathways. Rats had reduced spasticity and improved functional locomotor recovery. In conclusion, I have evaluated three different treatments after corticospinal tract injury, which all improved functional, neurophysiological and anatomical outcomes.
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McShane, Christie. "Enhancing corticospinal tract neurite outgrowth using histone deacetylase inhibitors." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/36113.
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The human corticospinal tract (CST) is responsible for coordinated voluntary movement and it contains descending afferent inputs involved in autonomic control and gating of spinal reflexes. After spinal cord injury (SCI), damage to the CST causes degeneration of axons and can result in major motor impairments. The CST is especially lacking in its capacity to regenerate after injury. In the current study, we harvested the cortices of postnatal day 8 Thy1YFP16JRS mice, which express YFP in layer five projection neurons, which also express CST transcription factors Ctip2 and Otx1 in vitro. We applied Histone deacetylase (HDAC) inhibitors (Trichostain A [TSA] and Tubastatin A) to the mixed neuron culture and assessed survival and neurite outgrowth of YFP positive CST neurons. TSA treatment increased the number of primary neurites per neuron and the number of branch points exhibited by YFP positive CST neurons. Application of either TSA or Tubastatin A, promoted YFP positive CST neurite outgrowth in baseline media as well as in the presence of the neurotrophin 3 (NT3) and cilliary neurotrophic factor (CNTF), compared to the appropriate controls. Taken together, the application of HDAC inhibitors to postnatal corticospinal neurons can promote neurite outgrowth, branching and an increase in the number of primary neurites when grown in baseline media.
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Cohen, Nicola R. "The development of the corticospinal decussation in rat, mouse and ferret." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670247.
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Talmi, Sydney. "The Rhesus Macaque Corticospinal Connectome." Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/cmc_theses/2087.
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The corticospinal tract (CST), which carries commands from the cerebral cortex to the spinal cord, is vital to fine motor control. Spinal cord injury (SCI) often damages CST axons, causing loss of motor function, most notably in the hands and legs. Our preliminary work in rats suggests that CST circuitry is complex: neurons whose axons project to the lower cervical spinal cord, which directly controls hand function, also send axon collaterals to other locations in the nervous system and may engage parallel motor systems. To inform research into repair of SCI, we therefore aimed to map the entire projection pattern, or “connectome,” of such cervically-projecting CST axons. In this study, we mapped the corticospinal connectome of the Rhesus macaque - an animal model more similar to humans, and therefore more clinically relevant for examining SCI. Comparison of the Rhesus macaque and rat CST connectome, and extrapolation to the human CST connectome, may improve targeting of treatments and rehabilitation after human SCI.
To selectively trace cervically-projecting CST motor axons, a virus encoding a Cre-recombinase-dependent tracer (AAV-DIO-gCOMET) was injected into the hand motor cortex, and a virus encoding Cre-recombinase (AAV-Cre) was injected into the C8 level of the spinal cord. In this intersectional approach, the gCOMET virus infects many neurons in the cortex, but gCOMET expression is not turned on unless the nucleus also contains Cre-recombinase, which must be retrogradely transported from axon terminals in the C8 spinal cord. Thus, gCOMET is only expressed in neurons that project to the C8 spinal cord, and it proceeds to fill the entire neuron, including all axon collaterals. Any gCOMET-labeled axon segments observed in other regions of the nervous system are therefore collaterals of cervically-projecting axons. gCOMET-positive axons were immunohistochemically labeled, and axon density was quantified using a fluorescence microscope and Fiji/ImageJ software. Specific regions of interest were chosen for analysis because of their known relevance in motor function in humans, and for comparison to results of a similar study in rats. Results in the first monkey have revealed both similarities and differences between the monkey and rodent CST connectome. Analyses of additional monkeys are ongoing. The final results will provide detailed information about differences between rodent and primate CST, will serve as a baseline for examining changes in the CST connectome after SCI, and will provide guidance for studies targeting treatment and functional recovery after SCI.
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Karimi-Abdolrezaee, Soheila. "Potential developmental stop signals for GAP-43 expression during corticospinal tract growth." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63885.pdf.
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Jaiser, Stephan Rudolf. "Non-invasive electrophysiological assessment of the corticospinal tract in health and disease." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2397.
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To date, no candidate markers of upper motor neuron (UMN) function have performed sufficiently well to enter widespread clinical use, and the lack of such markers impedes both the diagnostic process and clinical trials in motor neuron disease (MND). We studied 15-30Hz intermuscular coherence (IMC), a novel marker of UMN function, and central motor conduction time (CMCT), an established marker of UMN function based on transcranial magnetic stimulation (TMS), in healthy volunteers and patients newly diagnosed with MND. To clarify the relative contributions of different parts of the motor system to IMC generation, we examined IMC in patients with longstanding diagnoses of hereditary spastic paraparesis (HSP), multifocal motor neuropathy (MMN) and inclusion body myositis (IBM). Previous studies reported conflicting results for the relationship between CMCT and predictors such as age and height. We only found a significant correlation between lower limb CMCT and height. IMC did not vary significantly with age, allowing data from healthy subjects across all ages to be pooled into a single normative dataset. The variability of IMC between subjects was considerable, and within a given subject variability was greater between than within recording sessions; potential contributors are discussed. Anodal transcranial direct current stimulation (tDCS) caused a significant increase in IMC, but interindividual variability was substantial, which might hinder its future use as an adjunct to IMC. To compare individual disease groups to the normal cohort, we evaluated the area under the receiver-operating characteristic curve (AUC). IMC generally matched or exceeded the performance of CMCT in discriminating patients with MND from normal, achieving AUCs of 0.83 in the upper and 0.79 in the lower limb. Previous evidence suggests that IMC abnormalities are primarily attributable to corticospinal tract (CST) dysfunction. In line with this, most patients with HSP exhibited diminished IMC. However, patients with MMN also showed decreased IMC, suggesting either that subclinical CST involvement was present or that dysfunction of lower motor neurons (LMNs) may affect IMC; clarification through computational modelling is suggested. In iii IBM, IMC was generally increased, which might reflect that the altered motor unit discharge pattern makes synchronisation more readily detectable. IMC appears to be a promising marker of CST function. It remains to be clarified how strongly it is influenced by LMN lesions, and optimisation of methods should help to minimise the variability of results. Since IMC is non-invasive and can be measured using commonly available EMG equipment, wider dissemination should prove straightforward.
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Davidson, Travis. "Functional and Neurophysiological Correlates of Corticospinal Function in Human Aging." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20194.
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Transcranial magnetic stimulation (TMS) is a non-invasive technique that can be used to assess the integrity neuronal circuits in the motor cortex, both at the intrahemispheric and interhemispheric level. In the present study, TMS was used to examine age-related modulation of corticospinal function. Participants underwent hand function testing to examine possible links between TMS measures and manual ability. Participants consisted of healthy young (n=13) and senior (n=17) right-handed individuals. Hand function testing consisted of a battery of tests administered bilaterally to assess each participant’s dexterity, strength, movement speed and reaction time. The following TMS measures were assessed bilaterally: resting motor threshold, recruitment curve and silent periods of the contralateral and ipsilateral hand. Both young and senior subjects showed significant intermanual differences in most behavioral measures, favoring their dominant right hand. There was an age-related difference in TMS measures indicating a decline in intrahemispheric excitability and interhemispheric inhibition. A general trend linking specific TMS measures in the active state with age-related changes in hand function on the dominant hand was found. Our results suggest that TMS markers of corticospinal excitability can be used to predict declining hand function with age and thus could provide an early diagnosis of pathological aging.
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Popeo, Mariagrazia. "The effect of diffusion gradient direction number on tractography of corticospinal tract in human brain: an along-tract analysis." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8953/.
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Nel presente lavoro di tesi ho sviluppato un metodo di analisi di dati di DW-MRI (Diffusion-Weighted Magnetic Resonance Imaging)cerebrale, tramite un algoritmo di trattografia, per la ricostruzione del tratto corticospinale, in un campione di 25 volontari sani.
Il diffusion tensor imaging (DTI) sfrutta la capacità del tensore di diffusione D di misurare il processo di diffusione dell’acqua, per stimare quantitativamente l’anisotropia dei tessuti. In particolare, nella sostanza bianca cerebrale la diffusione delle molecole di acqua è direzionata preferenzialmente lungo le fibre, mentre è ostacolata perpendicolarmente ad esse. La trattografia utilizza le informazioni ottenute tramite il DW imaging per fornire una misura della connettività strutturale fra diverse regioni del cervello. Nel lavoro si è concentrata l’attenzione sul fascio corticospinale, che è coinvolto nella motricità volontaria, trasmettendo gli impulsi dalla corteccia motoria ai motoneuroni del midollo spinale.
Il lavoro si è articolato in 3 fasi. Nella prima ho sviluppato il pre-processing di immagini DW acquisite con un gradiente di diffusione sia 25 che a 64 direzioni in ognuno dei 25 volontari sani. Si è messo a punto un metodo originale ed innovativo, basato su “Regions of Interest” (ROIs), ottenute attraverso la segmentazione automatizzata della sostanza grigia e ROIs definite manualmente su un template comune a tutti i soggetti in esame. Per ricostruire il fascio si è usato un algoritmo di trattografia probabilistica che stima la direzione più probabile delle fibre e, con un numero elevato di direzioni del gradiente, riesce ad individuare, se presente, più di una direzione dominante (seconda fibra). Nella seconda parte del lavoro, ciascun fascio è stato suddiviso in 100 segmenti (percentili). Sono stati stimati anisotropia frazionaria (FA), diffusività media, probabilità di connettività, volume del fascio e della seconda fibra con un’analisi quantitativa “along-tract”, per ottenere un confronto accurato dei rispettivi percentili dei fasci nei diversi soggetti. Nella terza parte dello studio è stato fatto il confronto dei dati ottenuti a 25 e 64 direzioni del gradiente ed il confronto del fascio fra entrambi i lati. Dall’analisi statistica dei dati inter-subject e intra-subject è emersa un’elevata variabilità tra soggetti, dimostrando l’importanza di parametrizzare il tratto.
I risultati ottenuti confermano che il metodo di analisi trattografica del fascio cortico-spinale messo a punto è risultato affidabile e riproducibile. Inoltre, è risultato che un’acquisizione con 25 direzioni di DTI, meglio tollerata dal paziente per la minore durata dello scan, assicura risultati attendibili. La principale applicazione clinica riguarda patologie neurodegenerative con sintomi motori sia acquisite, quali sindromi parkinsoniane sia su base genetica o la valutazione di masse endocraniche, per la definizione del grado di contiguità del fascio. Infine, sono state poste le basi per la standardizzazione dell’analisi quantitativa di altri fasci di interesse in ambito clinico o di studi di ricerca fisiopatogenetica.
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Kitahara, Takahiro. "Axonal Extensions along Corticospinal Tracts from Transplanted Human Cerebral Organoids." Kyoto University, 2021. http://hdl.handle.net/2433/261613.
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Li, Ying. "Axon growth in the adult rat spinal cord." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308967.
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Semmler, John Gregory. "Effect of training on corticospinal control of human motor units /." Title page, table of contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phs471.pdf.
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Adams, Elysia. "The development of the corticospinal tract in premature newborns : impact of early brain injury." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/7291.
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Early brain abnormalities, including white matter injury, intraventricular hemorrhage and ventriculomegaly are associated with abnormalities of early motor functioning in premature neonates. Similarly, an increased risk of neurodevelopmental impairment is found in neonates with postnatal infections. The mechanism by which these factors impair motor functioning is largely unknown, but may result from altered development of white matter motor tracts. The purpose of this study was to evaluate the impact of brain abnormalities and neonatal illness on corticospinal tract (CST) development in premature neonates serially studied with diffusion tensor tractography (DTT). Fifty-five premature neonates between 24 and 32 weeks gestation at birth were scanned 2-4 weeks after birth, and again at term-equivalent age. Moderate to severe brain abnormalities (abnormal-MRI) were characterized by at least one of: moderate or severe white matter injury, moderate or severe intraventricular hemorrhage, or ventriculomegaly. CST DTT was performed using DTIStudio with seeding in the posterior limb of the internal capsule and filtering at the precentral gyrus and cerebral peduncle. This yielded CST diffusion parameters (fractional anisotropy; FA and average diffusivity; Dav), indicators of microstructural development. The effect of abnormal-MRI and neonatal illness on CST FA and Dav was assessed. Twenty-one neonates (38%) had abnormal-MRI on at least 1 of 2 scans. In neonates with normal MRIs, FA increased by 0.011 per week; Dav decreased by 1.9x10-⁵ mm²/sec (both P<0.001). In neonates with abnormal-MRI, however, FA increased at a significantly slower rate of 0.008 per week (interaction term P=0.05); Dav was 1.5x10-⁵ mm²/sec higher for any given age at scan (P<0.001). Changes in FA resulted from a decrease in radial, rather than axial, diffusivity. Radial diffusivity was higher in neonates with abnormal-MRI. Additionally, 23 neonates (42%) were exposed to a postnatal clinical infection. FA increased more slowly in neonates with postnatal infection (interaction term P=0.04), with a borderline slower rate of decrease in Dav (interaction term P=0.08). These results demonstrate that CST microstructural development, including maturation of the glial cells surrounding the axon, is impaired in premature neonates with abnormal-MRI. Maturation of the CST is also impaired in neonates with postnatal infections, independent of these abnormalities.
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Keyvan-Fouladi, Naghmeh. "Functional repair of the corticospinal tract by delayed transplantation of olfactory ensheathing cells in adult rats." Thesis, Open University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402238.
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Le, Friec Alice. "Evolution of corticospinal tract integrity in stroked marmoset monkeys : Towards a bioimplant and stem cell therapeutic strategy." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30031.
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L'Accident Vasculaire Cérébral (AVC) ischémique endommage fréquemment des régions cérébrales impliquées dans le contrôle du mouvement volontaire. De fait, cette pathologie est l'une des premières causes de handicap acquis à l'âge adulte. Bien que des centaines de stratégies thérapeutiques aient montré de potentiels effets bénéfiques dans des modèles animaux d'AVC, seule la rééducation motrice est validée comme traitement des déficits moteurs après la phase aiguë chez l'Homme. Ce constat souligne l'importance de développer et de caractériser des modèles pré cliniques reproductibles chez une espèce proche de l'homme, qui permettront de mieux évaluer l'efficacité de thérapies innovantes. Le premier objectif de ma thèse était donc de caractériser les conséquences anatomiques et fonctionnelles d'une lésion cérébrale induite par une toxine mitochondriale, le malonate, chez le rongeur et le primate non humain. Sur le plan anatomique, l'Imagerie par Résonance Magnétique multimodale a permis un suivi longitudinal non-invasif des altérations tissulaires. Celles-ci ont été explorées plus spécifiquement par des analyses histologiques. Les déficits moteurs ont été évalués par une batterie de tests sensorimoteurs. Nous montrons premièrement que l'injection stéréotaxique de malonate dans la capsule interne du rat permet une lésion ciblée des fibres du faisceau corticospinal (FCS). Cette lésion est associée à des déficits moteurs de longue durée, similaires à ceux observés suite à un AVC lacunaire chez l'Homme. Dans un deuxième temps, j'ai caractérisé les conséquences de l'injection stéréotaxique de malonate au niveau du cortex moteur primaire chez le marmouset. Ce modèle a été conçu afin de reproduire les effets d'une lésion corticale du FCS qui est fréquente dans l'AVC ischémique. Cette approche produit une lésion focale de volume et de localisation reproductible. Des lésions secondaires hypointenses en IRM pondérée T2 et hyperintenses en IRM pondérée T1 et associées à une infiltration d'astrocytes et de microglie sont observées dans la substance blanche à distance du site de la lésion, vraisemblablement suite à la perte de neurones qui font partie des boucles motrices cortico-sous-corticales. Fait important à noter, ces dommages sont associés à une perte durable de force et de dextérité du membre supérieur des animaux. L'injection stéréotaxique de malonate reproduit donc les conséquences de l'AVC ischémique, conduit à des déficits chroniques et permettra donc l'évaluation de nouvelles stratégies thérapeutiques. Parmi celles-ci, la thérapie cellulaire semble un moyen prometteur de favoriser la réparation tissulaire.[...]Ischemic stroke frequently damages brain regions involved in the control of voluntary movement and remains a leading cause of adult-acquired disability. Although hundreds of therapeutic strategies have shown potential benefits in animal models of stroke, motor rehabilitation and physiotherapy remain the only validated treatments in Humans after the acute phase. This observation highlights the need to develop and characterize reproducible pre-clinical models, which will allow the assessment of experimental therapies. The first objective of this work was therefore to characterize the anatomical and functional consequences of a brain lesion induced by stereotaxic injection of malonate, a mitochondrial toxin, in rodents and primates. Multimodal Magnetic Resonance Imaging allowed longitudinal non-invasive assessment of tissue alterations. We then performed histological analyses to further describe tissue damage. Motor deficits and their recovery were evaluated using a battery of sensorimotor tests. We first show that stereotaxic injection of malonate into the internal capsule of rats creates targeted destruction of corticospinal tract fibers. This lesion is associated with long term motor impairments similar to those observed after lacunar stroke in humans. Secondly, I characterized the consequences of stereotaxic injection of malonate into the primary motor cortex of marmoset monkeys. This model was developed in order to reproduce the effects of middle cerebral artery stroke in Humans. Indeed, the blood supply of motor territories strongly depends on this vessel, which is often occluded in ischemic stroke. We show that this approach causes a focal lesion of predictable size and location. Secondary lesions together with astrocyte and microglial infiltration were observed in white matter tracts distant to the lesion site, and likely occur after degeneration of cortico-sub-cortical motor loop axons. Importantly, the lesion was associated with long-lasting loss of dexterity and grip strength of the contralateral forelimb. Stereotaxic injection of malonate therefore reproduces the consequences of ischemic stroke and should allow the investigation of innovative therapies. Stem cell therapy may hold promise for tissue regeneration in the central nervous system (CNS). Co-transplantation of stem cells with biomaterials is currently investigated to enhance the survival and maturation of transplanted cells within the lesion site. Biomaterials can help to create a microenvironment permissive to cell integration within host tissue. An approach combining intracerebral engraftment of semi-rigid micro patterned biomaterials with human neural stem cells (to form a "neuro-implant") improved the recovery of grip strength in stroked rats. [...]
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Keefe, Kathleen Mary. "In Vivo Visualization of Neural Pathways in the Rat Spinal Cord Using Viral Tracing." Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/521830.
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NeurosciencePh.D.
Much of our understanding of the fascinating complexity of neuronal circuits comes from anatomical tracing studies that use dyes or fluorescent markers to highlight pathways that run through the brain and spinal cord. Viral vectors have been utilized by many previous groups as tools to highlight pathways or deliver transgenes to neuronal populations to stimulate growth after injury. In a series of studies, we explore anterograde and retrograde tracing with viral vectors to trace spinal pathways and explore their contribution to behavior in a rodent model. In a separate study, we explore the effect of stimulating intrinsic growth programs on regrowth of corticospinal tract (CST) axons after contusive injury. In the first study, we use self-complimentary adeno associated viral (scAAV) vectors to trace long descending tracts in the spinal cord. We demonstrate clear and bright labeling of cortico-, rubro- and reticulospinal pathways without the need for IH, and show that scAAV vectors transduce more efficiently than single stranded AAV (ssAAV) in neurons of both injured and uninjured animals. This study demonstrates the usefulness of these tracers in highlighting pathways descending from the brain. Retrograde tracing is also a key facet of neuroanatomical studies involving long distance projection neurons. In the next study, we highlight a lentivirus that permits highly efficient retrograde transport (HiRet) from synaptic terminals within the cervical and lumbar enlargements of the spinal cord. By injecting HiRet, we can clearly identify supraspinal and propriospinal circuits innervating MN pools relating to forelimb and hindlimb function. We observed robust labeling of propriospinal neurons, including high fidelity details of dendritic arbors and axon terminals seldom seen with chemical tracers. In addition, we examine changes in interneuronal circuits occurring after a thoracic contusion, highlighting populations that potentially contribute to spontaneous behavioral recovery in this lesion model. In a related study, we use a modified version of HiRet as part of a multi-vector system that synaptically silences neurons to explore the contribution of the rubrospinal tract (RST) and CST to forelimb motor behavior in an intact rat. This system employs Tetanus toxin at the neuronal synapse to prevent release of neurotransmitter via cleavage of vesicle docking proteins, effectively preventing the propagation of action potentials in those neurons. We find that shutdown of the RST has no effect on gross forelimb motor function in the intact state, and that shutdown of a small population of CST neurons in the FMC has a modest effect on grip strength. These studies demonstrate that the HiRet lentivirus is a unique tool for examining neuronal circuitry and its contribution to function. In the final study, we explore stimulation of the Phosphoinositide 3-kinase/Rac-alpha serine/threonine Protein Kinase (PI3K/AKT) growth pathway by antagonizing phosphatase and tensin homolog (PTEN), a major inhibitor, to encourage growth of CST axons after a contusive injury. We use systemic infusions of four distinct PTEN antagonist peptides (PAPs) targeted at different sites of the PTEN protein. We find robust axonal growth and sprouting caudal to a contusion in a subset of animals infused with PAPs targeted to the PTEN enzymatic pocket, including typical morphology of growing axons. Serotonergic fiber growth was unaffected by peptide infusion and did not correlate with CST fiber density. Though some variability was seen in the amount of growth within our animal groups, we find these PTEN antagonist peptides a promising and clinically relevant tool to encourage CST sprouting, and a potentially useful addition to therapies using combinatory strategies to enhance growth. These studies demonstrate that viral tracing is a powerful tool for mapping spinal pathways and elucidating their ability to reform spinal circuits after injury. Viral vectors can be used in both anterograde and retrograde tracing studies to highlight intricacies of neuronal cell bodies, axons and dendritic arbors with a high degree of fidelity. In the injured state, these tools can help identify pathways that contribute to spontaneous recovery of function by highlighting those that reform circuits past an injury site. In the uninjured state, these vectors can contain neuronal silencing methods that help define the contribution of specific pathways to behavior.
Temple University--Theses
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Van, Den Bos M. A. J. "Observations on the variability of corticospinal tract excitability during the reaction time period for simple human finger movements." Thesis, University College London (University of London), 2016. http://discovery.ucl.ac.uk/1505877/.
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There is extensive evidence that movements are prepared prior to their release. Transcranial magnetic stimulation, and in particular the motor evoked potential produced when stimulating over the primary motor cortex, has given a great deal of insight into the processes involved in preparation for voluntary movements. The excitability of the primary motor cortex remains in a state of dynamic fluctuation even when in the “resting” state, with the TMS MEP being exquisitely sensitive to this as evidenced by its tremendous trial to trial variability. Interestingly there is growing body of evidence to suggest that modulation of signal noise can provide insight into biological processes including movement preparation – indeed the output of the corticospinal tract would logically need to adapt to resting variability to enable the precise reproduction of movements. While much of the TMS literature has addressed MEP variability as a “noisy” signal, this thesis aims to assess whether elements of this “noise” can be utilized as a marker of biologic process during the reaction time period for simple human finger movements. Through successive chapters we demonstrate that the variability of corticospinal tract output, as evidenced by the TMS MEP, declines during the process of preparation for simple human finger movements. We demonstrate that the reaction time decline in variability is focal to muscles directly involved in the task. Furthermore, the rate of decline in MEP amplitude variability during the reaction time period appears intimately linked to the speed of movement initiation. Additionally, the changes we see here precede changes in mean excitability in agonists, and indeed are seen to be associated with a decline in mean excitability when surround muscles are tasked with deliberate inactivity. Finally, observations in stroke patients suggest an alteration in variability control during movement preparation and appear to be associated with concordant changes in task performance.
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Yamamoto, Mie. "Transplanted olfactory mucosal cells restore paw reaching function without regeneration of severed corticospinal tract fibres across the lesion." Kyoto University, 2010. http://hdl.handle.net/2433/120554.
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Sano, Noritaka. "Enhanced Axonal Extension of Subcortical Projection Neurons Isolated from Murine Embryonic Cortex using Neuropilin-1." Kyoto University, 2018. http://hdl.handle.net/2433/231009.
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Frezel, Noémie. "Modulation du traitement sensoriel par des projections descendantes directes du cortex somatosensoriel vers la moelle épinière." Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEE018.
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Les stimuli nociceptifs sont détectés par des neurones sensoriels spécialisés du système nerveux périphérique appelés nocicepteurs. L’information nociceptive est ensuite traitée dans la corne dorsale de la moelle épinière, qui contient des interneurones locaux et des neurones de projection qui envoient des axones vers le cerveau. Les aires supra-spinales projettent à leur tour vers la moelle épinière, où elles contribuent à la synchronisation des signaux nociceptifs. Une sensibilité à la douleur exagérée et anormale s'accompagne d'altérations du traitement de l’information dans la moelle épinière dans les systèmes de contrôle descendants de la douleur. La connexion entre le cortex somatosensoriel en particulier et la moelle épinière est conservée chez les mammifères, mais très peu de choses sont connues sur son rôle dans la modulation du traitement sensoriel dans la moelle épinière. Un défi majeur dans l’étude des circuits neuronaux est de de marquer et de cibler spécifiquement des groupes ou sous-groupes définis de neurones. Les approches classiques incluent le ciblage de populations neuronales définies génétiquement, i.e. sur la base de l'expression d'un gène marqueur. Cependant, cela ne suffit pas toujours pour définir des groupes de neurones fonctionnellement distincts. Ici, nous décrivons et utilisons des stratégies de marquage génétiques et virales basées sur la connectivité des neurones ainsi que sur l’expression d’un ou de deux gènes marqueurs. En particulier, nous avons utilisé une combinaison de lignées de souris transgéniques et d'injections intra-spinales et corticales de vecteurs viraux recombinants pour identifier et cibler des neurones spécifiques du cortex et de la moelle épinière lombaire. Nous avons identifié une population de neurones pyramidaux dans le cortex somatosensoriel qui projettent directement dans la corne dorsale (neurones S1-CST). Ces neurones établissent un contact direct avec les interneurones exprimant c-maf dans la corne dorsale profonde, qui reçoivent également des contacts directs d’afférents primaires mécano-sensoriels à bas seuil. De plus, la manipulation pharmacogénétique des neurones c-maf a entraîné des modifications dans le traitement des stimulations sensorielles mécaniques. Ces résultats identifient deux éléments d’un circuit qui intègre les informations descendantes du cortex avec des signaux sensoriels périphériques et contribue à la modulation de la perception somatosensorielleNoxious stimuli are sensed by specialized sensory neurons of the peripheral nervous system called nociceptors. The nociceptive information is then processed in the spinal cord dorsal horn, which contains local interneurons and projection neurons that send axons to the brain. Supraspinal areas in turn project downwards to the spinal cord where they contribute to the gating of nociceptive signals. Exaggerated and abnormal pain sensitivity is accompanied by alterations in spinal processing and descending pain control systems. The connection between the somatosensory cortex in particular and the spinal cord is conserved in mammals, but very little is known about its role in modulating spinal sensory processing. A major challenge of studying neuronal circuits is to specifically label and target defined groups or subgroups of neurons. Classical approaches include targeting of genetically defined neuronal populations based on the expression of a marker gene. However, this is not always sufficient to define functionally distinct groups of neurons. Here, we describe and used genetic and viral tageting strategies based on the connectivity pattern of the neurons as well as the expression of one or two marker genes. In particular, we used a combination of transgenic mouse lines and intraspinal and cortical injections of recombinant viral vectors to identify and target specific neurons in the cortex and lumbar spinal cord. We identified a population of pyramidal neurons in the somatosensory cortex that project directly to the spinal dorsal horn (S1-CST neurons). These neurons make direct contacts onto c-maf expressing interneurons in the deep dorsal horn which also receive direct inputs from low threshold mechanosensory primary afferents. Additionnally, pharmacogenetic manipulation of c-maf neurons led to altered processing of mechanical stimuli. These results identify two elements of a circuit that integrates descending inputs from the cortex with peripheral sensory signals and contributes to the modulation of somatosensory perception
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Tocco, Chiara. "Caractérisation morphologique, électrophysiologique et topographique des neurones de la couche V dans un modèle murin de maladie neurodéveloppementale." Electronic Thesis or Diss., Université Côte d'Azur, 2021. http://theses.univ-cotedazur.fr/2021COAZ6004.
Full textAbstract:
Chez les mammifères, la bonne exécution des mouvements volontaires fins repose sur des réseaux neuronaux complexes qui relient diverses régions du cerveau, tel que le cortex, les ganglions de la base, les noyaux pontins, le cervelet et le thalamus. La compréhension des mécanismes génétiques et moléculaires qui sous-tendent l'organisation neuronale de ces circuits améliorera notre connaissance de la façon dont les réseaux moteurs sont normalement établis au cours du développement et affectés dans les maladies neurodéveloppementales. Les neurones pyramidaux de la couche V à projection sous-corticale (LVPN) sont, entre autres, au cœur de ce circuit.Nous avons précédemment montré que la perte génétique du facteur de transcription Nr2f1 dans le cortex en développement affecte l'organisation des aires fonctionnels du néocortex, la région évolutivement plus récente du cortex cérébral, et la spécification moléculaire des neurones LVPN, entraînant des fonctions motrices volontaires défectueuses tant chez les modèles murins que chez les patients humains présentant une haploinsuffisance du gène NR2F1. Pour mieux évaluer la contribution de Nr2f1 dans l'établissement des réseaux sous-corticaux, nous avons utilisé deux lignées de souris mutantes pour Nr2f1 et avons étudié les caractéristiques électrophysiologiques, morphologiques et de connectivité des neurones LVPN à différents stades de développement.Nos données électrophysiologiques et morphologiques révèlent que les neurones mutants postnatals sont caractérisés par une excitabilité intrinsèque accrue et une complexité réduite des dendrites, ce qui indique que Nr2f1 joue un rôle clé dans la maturation fonctionnelle des LVPN pendant le développement cortical. En outre, le traçage génétique des projections dans les cerveaux mutants montre une cartographie topographique anormale entre le cortex et les noyaux pontins, ce qui implique que les neurones corticaux doivent normalement acquérir une propre identité positionnelle avant d’établir des projections sous-corticales appropriées. Dans l'ensemble, nos données indiquent que le gène Nr2f1 est impliqué dans l'établissement des propriétés fonctionnelles et structurelles des neurones LVPN, ainsi que dans l'organisation topographique des projections cortico-pontines, premiers acteurs du circuit cortico-ponto-cérébelleux impliqués dans la motricité fineIn mammals, the proper execution of fine voluntary movements relies on complex, but highly organized neuronal networks connecting various regions of the brain, such as the cerebral cortex, basal ganglia, pontine nuclei, cerebellum and thalamus. Understanding the genetic and molecular mechanisms underlying the neuronal organization of these circuits may improve our knowledge of how motor networks are normally established during development and affected in neurodevelopmental diseases. Among others, subcortically projecting Layer V Pyramidal Neurons (LVPNs) are central to this circuit.We have previously shown that the genetic loss of the transcription factor Nr2f1 in the developing neocortex, the evolutionary most recent region of the cerebral cortex, affects areal organization and molecular specification of LVPNs, leading to defective voluntary motor functions in both mouse models and human NR2F1 haploinsufficient patients. To further assess the contribution of Nr2f1 in the establishment of cortico-subcortical networks, we used two independent Nr2f1 conditional mutant mouse lines and investigated electrophysiological, morphological and connectivity features of LVPNs at different developmental stages.Our electrophysiological and morphological data reveal that postnatal mutant LVPNs are characterized by increased intrinsic excitability and reduced dendrite complexity, indicating that Nr2f1 plays a key role in LVPN functional maturation during cortical development. Moreover, genetic tracing of LVPN projections in mutant brains shows abnormal topographic mapping between the cortex and pontine nuclei, implying that LVPNs need to acquire their proper areal identity to establish normal subcortical projections. Overall, our data indicate that Nr2f1 is involved in the establishment of functional and structural properties of LVPNs, as well as in the topographic organization of cortico-pontine projections, first players of the cortico-ponto-cerebellar circuit involved in fine motor skills
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Arnould, Carlyne. "Hand functioning in children with cerebral palsy / Le fonctionnement de la main chez les enfants infirmes moteurs d'origine cérébrale." Université catholique de Louvain, 2006. http://edoc.bib.ucl.ac.be:81/ETD-db/collection/available/BelnUcetd-01242006-153948/.
Full textAbstract:
The purpose of the present work was to study hand impairments and manual ability in children with cerebral palsy (CP) as well as to clarify their relationship. Appraising the degree of hand impairments requires normative data to differentiate the real dysfunctions of CP children from the normal difficulties according to their age, sex, or handedness. As there is no normative data for gross manual and fine finger dexterity, a first experiment focused on the normal development of manipulative functions was conducted to establish these norms. A second experiment was carried out to develop and validate through the Rasch model a measure of manual ability in children with CP since such a measure was not yet available. The invariance of the ABILHAND-Kids questionnaire was also tested across relevant demographic and clinical subgroups of CP children. Finally, a third experiment was performed to quantify the hand impairments in children with CP and to investigate their relationship with manual ability as measured with the ABILHAND-Kids questionnaire. Hand motor impairments, markedly more prevalent than hand sensory impairments, were moderately correlated with manual ability measures and predicted 58% of their variance. Consequently, manual ability cannot simply be inferred from hand impairments and should be measured and treated per se. / L'objectif de ce travail était d'étudier les déficiences de la main et l'habileté manuelle chez les enfants infirmes moteurs d'origine cérébrale (IMOC) ainsi que de clarifier leur relation. Apprécier la gravité des déficiences de la main nécessite des données normatives afin de différencier les dysfonctionnements réels des enfants IMOC des difficultés normales compte tenu de leur âge, sexe, ou latéralité. Etant donné l'absence de normes quant à la dextérité manuelle grossière et la dextérité digitale fine, une première étude a été réalisée afin d'examiner le développement normal de ces deux types de dextérité. Des normes sur les dextérités manuelle grossière et digitale fine ont ainsi pu être établies. Une deuxième étude a été effectuée afin de développer et valider à travers le modèle de Rasch une mesure de l'habileté manuelle chez les enfants IMOC. L'invariance du questionnaire ABILHAND-Kids a également testée à travers différents sous-groupes démographiques et cliniques d'enfants IMOC. Enfin, une troisième étude a été réalisée afin de quantifier les déficiences de la main chez les enfants IMOC et d'investiguer leur relation avec l'habileté manuelle. Les déficiences motrices de la main, plus prévalentes que les déficiences sensitives, étaient modérément corrélées avec les mesures d'habileté manuelle et prédisaient 58% de leur variance. En conséquence, l'habileté manuelle ne peut être simplement inférée à partir des déficiences de la main et devrait donc être mesurée et traitée pour elle-même.
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Hill, Caitlin E. "Contusive Spinal Cord Injury: Endogenous Responses of Descending Systems and Effects of Acute Transplantion of Glial Restricted Precursor Cells." Connect to this title online, 2002. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1032795301.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2002.Title from first page of PDF file. Document formatted into pages; contains xiii, 177 p.; also includes graphics (some col.). Includes bibliographical references (p. 160-177). Available online via OhioLINK's ETD Center
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Fageiry, Samaher Khaireldin. "Mapping corticospinal connections with spinal circuits." Thesis, 2019. https://doi.org/10.7916/d8-w4p5-4e49.
Full textAbstract:
The majority of corticospinal projections in primates and all corticospinal projections in other mammals exert their influence by integrating into spinal interneuronal circuits. Interneurons therefore represent an evolutionarily conserved target through which the corticospinal tract achieves motor and sensory control. Here I describe the postnatal maturation of the corticospinal tract. I show work aimed at fractionating cortical projections by combining recently developed retrograde viral tracing strategies with genetic access to distinct spinal interneuron populations. Using a 3-D reconstruction pipeline, I discuss the cortical origins of the corticospinal pathway in mice. I then demonstrate the differential distribution of corticospinal inputs to three interneuron populations with divergent functional roles. These studies suggest that primary motor cortex contacts functionally diverse spinal interneurons whilst premotor and somatosensory cortical regions are more restricted in their postsynaptic targeting.
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Chen, Chun-Ming, and 陳君明. "Non-Interpolated Tract-Based Statistic Analysis for Estimating The Corticospinal Tract: A Comparison with Parkinson’s Disease, Essential Tremor and The Normal Control." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/31867763580407346730.
Full textAbstract:
博士國立中興大學
電機工程學系所
102
Diffusion tensor imaging (DTI) has been proved as a powerful tool for parameterizing microstructure changes with various neurodegenerative diseases such as Parkinson’s disease (PD) or essential tremor (ET). Although these two diseases have been reported as involving motor cortical dysfunction, the central mechanisms to induce their tremor symptoms are still remain unclear. Previously, researchers started using DTI to quantify white matter changes. However, they barely draw congruent conclusions. Among these studies, we found group quantifications with ROI-based methods seem to provide better sensitivity in detecting subtle changes than those with methods containing spatial normalization. In light of these findings, we hypothesize DTI quantification method that applied with minimal spatial transformation or interpolation could be more sensitive in detecting such alterations. In this thesis, we provided a full investigation to all mainstream DTI quantification approaches, including their concepts and features. We also compared their advantages and drawbacks. Then, we extended the application of the traditional ROI-based method to a 3D tract-specific one. In chapter 4, we provided a tract-based quantitative framework combined with minimal spatial preprocessing and performed a head-to-head comparison between PD, ET and the normal subjects. We also provided a small pilot study to determine the suitable protocol setting of the DTI sequence. The results showed that the FA distributions along the corticospinal tract have significant differences across groups. The ET group showed significant higher mean FAs in the internal capsule level of the CST bilaterally as compared to the normal group. The PD group also showed higher mean FAs, but in region near the level of thalamus. Comparing between the PD and ET groups, the ET group showed lower mean FA values around the midbrain region. Our presented approach successfully demonstrates the white matter changes to the PD, ET and normal subjects by estimating their corticospinal tracts. In such tractography-based statistical approach, we not only proved its advantages in giving detail along certain fiber tract compare to traditional ROI-based approach but also provided better sensitivity to detect subtle microstructure changes than other approaches involving spatial transformation.
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McGie, Steven. "Hebbian Neuroplasticity in the Human Corticospinal Tract as Induced by Specific Electrical and Magnetic Stimulation Protocols." Thesis, 2014. http://hdl.handle.net/1807/65703.
Full textAbstract:
Conventional functional electrical stimulation (FES) therapy, if provided shortly after an
incomplete spinal cord injury, is able to help an individual to restore voluntary hand
function. This is thought to occur through the induction of neuroplasticity. However,
conventional FES therapy employs a push-button-based control scheme, which does not
fully require the recipient to generate volitional movements. The first study in this thesis
therefore sought to determine, in an early proof-of-concept test with able-bodied
participants, whether control strategies which are triggered by volitional activity
(including an electroencephalography-based brain-machine interface (BMI-FES) and an
electromyogram-based control scheme (EMG-FES)) might provide greater benefits to
hand function. The results offer relatively weak evidence to suggest that BMI-FES, and
especially EMG-FES, were able to induce greater neuroplasticity than conventional
treatments in the corticospinal tract leading to the hands, but that this did not
immediately translate to more functional improvements such as maximum grip force.
ii
The second study in this thesis focussed on spinal associative stimulation (SAS), which
involves paired stimulation pulses at both the head (via transcranial magnetic
stimulation), and the wrist (via peripheral nerve stimulation). The purpose of this, as with
the first study, was to induce neuroplasticity and upregulate the corticospinal tract
leading to the hands. While limited research has suggested that it is possible to produce
neuroplasticity through SAS, all such studies have provided stimulation at a fixed
frequency of 0.1 or 0.2 Hz. The present study therefore sought to compare the
effectiveness of a typical 0.1 Hz paradigm with a 1 Hz paradigm, and a paradigm which
provided stimulation in 5 Hz “bursts”. None of the paradigms were able to successfully
induce neuroplasticity in a consistent manner. The increased variability in this study as
compared to the previous one, despite the nearly identical assessment methodology,
suggests that responses to the SAS treatment may have been highly individual. This
serves to highlight a potential limitation of the treatment, which is that its effectiveness
may not be universal, but rather dependent on each specific recipient. This may be a
challenge faced by SAS should it continue to be tested as a novel therapy.
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Kuo, Hsing-Ching. "The relationship between mirror movements and corticospinal tract connectivity in children with unilateral spastic cerebral palsy." Thesis, 2016. https://doi.org/10.7916/D8H1322W.
Full textAbstract:
Unilateral Spastic Cerebral Palsy (USCP) is caused by an early brain lesion in which the Corticospinal Tract (CST), the primary pathway controlling upper extremity (UE) movements, is affected. The CST connectivity after early brain injury (i.e., an ipsilateral, contralateral, or bilateral connectivity) may influence treatment outcomes. Transcranial magnetic stimulation (TMS) is a common method to probe CST connectivity. However, TMS is limited to children without seizures. Mirror movements (MM), an involuntary imitation of movements by one limb during the contralateral limb voluntary movements, are common in USCP. MM may result when both UEs are controlled by the contralesional motor cortex. Here we investigated the relationship between MM and CST connectivity in children with USCP. We hypothesized that stronger MM were associated with an ipsilateral connectivity. Our secondary aim was to investigate whether the amount of MM was reduced after intensive therapy. Thirty-three children with USCP (mean age=9yrs 6mos; MACS: I-III) participated and were randomized to receive 90hrs of unimanual (n=16) or bimanual (n=17) intensive training. Assessments were measured at baseline and immediately after training. We used TMS and diffusion tensor imaging (DTI) to determine the CST connectivity. We used three approaches to quantify MM: 1) behavioral MM assessment during contralateral movements, including hand opening/closing, finger opposition, finger individuation, and finger walking, 2) involuntary grip force oscillations recorded by force transducer (FT) when the contralateral hand performed repetitive pinching, and 3) involuntary muscle contractions measured by electromyography (EMG) when the contralateral hand performed pinching. Results showed that strong MM (scores ≥3) in the more-affected hand while hand opening/closing were associated with an ipsilateral pathway (Fisher's exact test, p= 0.02). This association was not found in the remaining tasks (Fisher’s exact test, opposition, p≥ 0.99; individuation, p≥ 0.99; finger walking, p≥ 0.99). Involuntary GF oscillations were measured in a subset of 16 children. Presence of FT-measured MM in the less-affected hand (> 0.3N) was not associated with TMS-probed connectivity (Fisher’s exact test, p= 0.59). Nevertheless, presence of FT-measured MM was associated with DTI-assessed connectivity (Fisher’s exact test, p= 0.0498). Similarly, presence of EMG-measured MM in the more-affected hand was not associated with TMS-probed connectivity (Fisher’s exact test, p= 0.59). Nevertheless, presence of EMG-measured MM was associated with DTI-assessed connectivity (Fisher’s exact test, p= 0.03). The amount of MM did not change after training (p> 0.06 among all measures). In conclusion, strong MM in the more-affected hand while hand opening/closing may be indicative of an ipsilateral connectivity identified by TMS. Presence of MM measured by FT may be a predictor of DTI-assessed CST pattern. Findings of this study may help researchers and clinicians understand the relationship between the CST connectivity and its behavioral manifestation in children with USCP. Such relationship may further guide therapeutic strategies in a wider range of children with USCP.
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Seif, Gamal. "Quantification of retrograde axonal degeneration ("dieback") in the rat corticospinal tract after axotomy : a confocal microscopy study using DiI." 2005. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=370401&T=F.
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LUPIDI, Francesco. "Diffusion Tensor Imaging corticospinal tractography for evaluation of motor pathways radiation exposure in Gamma Knife radiosurgery treatments." Doctoral thesis, 2010. http://hdl.handle.net/11562/343982.
Full textAbstract:
Obiettivo. Lo scopo di questa ricerca era dimostrare la fattibilità tecnica e l’utilità clinica dell’integrazione della trattografia basata sull’Imaging del Tensore di Diffusione (DTI) nei piani di trattamento con Gamma Knife (GK) per le malformazioni artero-venose, al fine di calcolare la dose che interessa il fascio corticospinale. Ci siamo proposti di raccogliere dati per valutare la tolleranza alle radiazioni del fascio corticospinale e per sviluppare modelli di rischio riguardanti i deficit motori conseguenti al trattamento.
Materiale e Metodi. Lo studio di DTI è stato realizzato con una Risonanza Magnetica (RM) a 3 Tesla con tecnica di imaging parallelo in 34 pazienti affetti da malformazione artero-venosa cerebrale situata in prossimità del fascio corticospinale e sottoposti a radiochirurgia con Gamma Knife. Dopo l’elaborazione dei dati di RM, la via motoria bilaterale veniva ricostruita tridimensionalmente. Un software specifico per la registrazione multimodale è stato sviluppato. I tratti di fibre ricostruiti erano registrati sui dati di RM T1 volumetrici, entrambi ottenuti a 3 Tesla. Quindi le risultanti immagini venivano registrate con lo studio di RM ad 1 Tesla, eseguito in condizioni stereotassiche, per realizzare l’integrazione della trattografia nel piano di trattamento. In 14 pazienti la valutazione dell’esposizione radiante del fascio corticospinale è stata realizzata in maniera retrospettiva successivamente alla procedura radiochirurgica; nei rimanenti pazienti l’integrazione della trattografia è stata applicata in maniera prospettica durante la realizzazione del piano di cura.
Risultati. Le fibre del fascio corticospinale sono state visualizzate sia nel caso di malformazioni artero-venose emorragiche che non emorragiche. Il numero di fibre ricostruite dal lato affetto era significativamente più basso nei pazienti con un deficit motorio preesistente al trattamento. Le complicazioni motorie post-radiochirurgiche erano significativamente correlate con il volume del fascio corticospinale ricevente una dose ≥ 12 Gy (P = 0,010). La dose integrale del fascio corticospinale era parimenti significativamente correlata allo sviluppo di deficit motori (P = 0,048). Sono stati elaborati modelli di dose-risposta per stimare la probabilità di sviluppare complicazioni motorie utilizzando l’analisi mediante regressione logistica. La sede della malformazione artero-venosa nei nuclei della base e la dislocazione del fascio corticospinale rispetto al suo decorso anatomico erano correlati con volumi più alti di fascio corticospinale esposti ad una dose ≥ 12 Gy. L’incidenza di complicazioni motorie è risultata più bassa nel gruppo prospettico rispetto al retrospettivo (5,0% contro 14,2%, rispettivamente).
Conclusioni. L’integrazione della trattografia basata su DTI a 3 Tesla nei piani di trattamento con GK per malformazioni artero-venose localizzate in prossimità del fascio corticospinale è una procedura realizzabile ed attendibile e può essere compatibile con un impiego routinario. Il volume del fascio corticospinale che riceve una dose ≥ 12 Gy e la dose integrale del fascio corticospinale sono fattori predittivi per lo sviluppo di deficit motori. La visualizzazione del fascio corticospinale permette di ottimizzare la pianificazione del trattamento radiochirurgico, realizzando così trattamenti specifici per il paziente con una riduzione della morbidità.Objective. The aim of this research was to demonstrate the technical feasibility and the clinical usefulness of Diffusion Tensor Imaging (DTI) tractography integration in the Gamma Knife (GK) treatment planning for arterio-venous malformations (AVMs) in order to calculate the dose delivery involving the corticospinal tract (CST). We purposed to collect data for the assessment of the CST radiation tolerance and for the development of risk models concerning treatment-related motor deficits. Material and Methods. DTI study was performed using a 3 Tesla Magnetic Resonance (MR) unit with parallel imaging technique in 34 patients harbouring cerebral AVMs in proximity of the CST undergoing GK radiosurgery. After the data processing, three-dimensional tracking of the bilateral motor pathway was carried out. An in-house software for multimodal registration was developed. The reconstructed fiber tracts were matched on T1 volumetric data set, both obtained at 3 Tesla. Then the resulting images were registered with the 1 Tesla MR study performed under stereotactic conditions for the integration in the treatment planning. In 14 patients the evaluation of CST radiation exposure was retrospectively performed after the radiosurgical procedure; in the remaining patients the integration of CST tractography was prospectively applied during the realization of the treatment planning. Results. The fibers of CST were highlighted in both non-hemorrhagic and hemorrhagic AVMs. The amount of reconstructed fibers on the affected side was significantly lower in patients with a preoperative motor deficit. Post-radiosurgical motor complications were strongly correlated to the volume of the CST receiving ≥ 12 Gy (P = 0.010). The integral dose of the CST was significantly related to the development of motor deficits as well (P = 0.048). Dose-response models were elaborated to estimate the probability of developing motor complications using logistic regression analyses. The location of the AVM in the basal ganglia and the displacement of the CST from its anatomical course were correlated with higher volumes of the CST receiving ≥ 12 Gy. The rate of motor complications resulted lower in the prospective group than in the retrospective (5.0% vs 14.2%, respectively). Conclusions. The integration of tractography based on 3 Tesla DTI in the GK treatment planning for AVMs in proximity of the CST is feasible and reliable and can be compatible within a routine clinical setting. The volume of the CST receiving ≥ 12 Gy and the integral dose of the CST are predictors of developing motor deficits. The visualization of the CST allows to optimize the radiosurgical planning, realizing patient-tailored treatments with a reduction of the morbidity.
29
Nepveu, Jean-François. "Les interactions vestibulo-corticales qui sous-tendent le contrôle de la posture chez les sujets sains." Thèse, 2016. http://hdl.handle.net/1866/16283.
Full textAbstract:
Le système vestibulaire et le cortex moteur participent au contrôle de la posture, mais la nature de leurs interactions est peu documentée. Afin de caractériser les interactions vestibulo-corticales qui sous-tendent le contrôle de l’équilibre en position debout, l’activité électromyographique (EMG) du soléaire (SOL), du tibial antérieur (TA) et du péronier long (PERL) de la jambe droite a été enregistrée chez 14 sujets sains. La stimulation galvanique vestibulaire (GVS) a été appliquée avec la cathode derrière l’oreille droite ou gauche à différents intervalles inter-stimulus (ISIs) avant ou après la stimulation magnétique transcrânienne induisant des potentiels moteurs évoqués (MEPs) au niveau des muscles enregistrés. Lorsque que la cathode était à droite, une inhibition des MEPs a été observée au niveau du SOL à un ISI de 40 et 130 ms et une facilitation des MEPS a été observée au niveau TA à un ISI de 110 ms. Lorsque la cathode était à gauche, une facilitation des MEPs a été observée au niveau du SOL, du TA et du PERL à un ISI de 50, -10 et 0 ms respectivement. L’emplacement de ces interactions sur l’axe neural a été estimé en fonction des ISIs et en comparant l’effet de la GVS sur les MEPs à son effet sur l’EMG de base et sur le réflexe-H. Selon ces analyses, les modulations observées peuvent avoir lieu au niveau spinal ou au niveau supraspinal. Ces résultats suggèrent que les commandes de la voie corticospinale peuvent être modulées par le système vestibulaire à différents niveaux de l’axe neuronal.The vestibular system and the motor cortex are involved in the control of posture but the nature of their interactions is poorly documented. To characterize vestibulo-cortical interactions underlying the control of balance during quiet standing, the electromyographic activity (EMG) of the soleus (SOL), tibialis anterior (TA) and peroneus longus (PERL) of the right leg was recorded in 14 healthy subjects. Bipolar galvanic vestibular stimulation (GVS) was applied with the cathode behind the right or left ear at various inter-stimulus intervals (ISI) before and after transcranial magnetic stimulation eliciting motor evoked potentials (MEP) in the muscles recorded. When the cathode was on the right, MEP in the SOL were inhibited at 40 and 130 ms while MEP were facilitated in TA at 110 ms. When the cathode was on the left, MEP were facilitated in the SOL at 50 ms, in TA at -10 ms and in PERL at 0 ms. The localization of these interactions along the neural axis was estimated according to the ISI and by comparing the effect of the GVS on the MEP to its effect on the background EMG and on the SOL H-reflex. Based on these analyses, the observed modulations of MEP observed could have occurred at spinal or supraspinal level. These results suggest that the corticospinal output may be modulated by the vestibular system at different levels of the neural axis.
30
Srivatsa, Swathi. "Transcriptional control of the establishment of neocortical projections in the mammalian telencephalon." Doctoral thesis, 2014. http://hdl.handle.net/11858/00-1735-0000-0023-997F-F.
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Chen, Hsiu-I., and 陳綉儀. "Associations of Cortical Activation Patterns and Integrity of Corticospinal Tract with Lower Extremity Motor Functions in Patients with Chronic Stroke: Neural Plasticity Studies." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/19792264435773671481.
Full textAbstract:
博士國立臺灣大學
物理治療學研究所
100
Study I: Purposes: The aim of this study was to examine how the intensity and lateralization of cortical activations in the primary sensorimotor cortex (SMC), supplementary motor area (SMA), and cingulate motor area (CMA) during ankle movements correlate with motor impairment and functional mobility in patients with chronic stroke. Methods: Functional magnetic resonance imaging (fMRI) data of cortical activations during active ankle dorsiflexion movements (0.17 Hz) were acquired using a 3 Tesla MR scanner from 15 patients (6 females and 9 males; mean age, 61.2 ± 7.6 years) with unilateral hemiplegia following stroke (mean post-onset time, 18.0 ± 15.8 months) and from 15 age-matched healthy subjects (5 males and 10 females; 61.6 ± 7.3 years). The lower extremity motor component of the Fugl-Meyer Assessment (FMALE) and the Timed “Up & Go” Test (TUGT) were used to assess motor impairment of the affected lower extremity and functional mobility of patients, respectively. The activation intensity in three paired regions of interest (ROIs)- the bilateral SMC, SMA, and CMA, were calculated by summing the t values (Σt) of voxels which t values were above the t threshold defined as 50% of the mean of the top 5% maximum t values in the corresponding homologous ROIs. The degree of lateralization of cortical activation in each pair of ROIs was calculated by using a weighted laterality index (wLI) proposed by Fernandez. An wLI value of +1 indicated absolute contralateral cortical activation during ankle movements, whereas an wLI value of -1 indicated absolute ipsilateral cortical activation. The correlations between the Σt values in bilateral SMC, SMA, and CMA, and the wLI values for each pair of SMC, SMA, and CMA with the FMALE and TUGT scores were analyzed using partial correlations, controlling for age and post-onset time. Results: The FMALE scores showed a significant negative correlation with the Σt value of SMC of the unaffected hemisphere (r= -0.627, p= 0.022) and a trend of positive correlation with the wLI of the SMC (r= 0.500, p= 0.082), suggesting that patients with greater affected lower extremity motor impairment presented greater activation intensity in the SMC of unaffected hemisphere and smaller lateralization of SMC activation during affected ankle movements. The TUGT performance showed a significant positive correlation with the Σt value of the SMC of the affected hemisphere (r= 0.729, p= 0.005), and a trend of correlation with the Σt values of the SMC of the unaffected hemisphere (r= 0.491, p= 0.09), with those of SMA of affected and unaffected hemispheres (r= 0.509, p= 0.076 and r= 0.542, p= 0.056, respectively), and with that of the CMA of the affected hemisphere (r= 0.524, p= 0.066). Patients with poorer functional mobility demonstrated greater activation intensity in bilateral SMC, SMA, and CMA of the affected hemisphere during affected ankle movements. Discussion and Conclusions: Results of this study revealed that different aspects of lower extremity motor functions in patients with chronic stroke were correlated with different adaptive cortical activation patterns in bilateral SMC, SMA, and CMA regions in patients with stroke. While patients’ degree of motor impairment of the affected lower extremity was primarily associated with the activation intensity and lateralization of the SMC, their functional mobility was associated with activation intensity in more widespread cortical motor regions, including bilateral SMC and SMA, and CMA of the affected hemisphere. These findings suggest that the recovery of motor impairment and functional mobility of stroke patients may depend upon functional reorganization of different brain regions. Study II: Purposes: The two purposes of this study were (1) to investigate the associations of the structural integrity of the corticospinal tract lower extremity motor fibers (CSTLE) and cortical activation patterns with the affected lower extremity motor functions in hemiplegic patients following chronic stroke and (2) to determine the relative contributions of the structural integrity of CSTLE and cortical activation patterns to affected lower extremity motor functions in these patients. Methods: Eighteen hemiplegic patients with chronic stroke (7 females and 11 males; mean age, 61.0 ± 7.4 years, mean post-onset time, 16.6 ± 15.0 months) were recruited. All patients underwent clinical measures and MRI scans using a 3 Tesla MR scanner. The lower extremity motor component of the Fugl-Meyer Assessment (FMALE) and the Timed “Up & Go” Test (TUGT) was used to assess motor impairment of affected lower extremity and functional mobility, respectively. Cortical activations during active ankle dorsiflexion movements were measured using an fMRI paradigm. Cortical activation patterns were assessed by calculating absolute summation of t values ( ) above activation threshold in the primary sensorimotor cortex (SMC), supplementary motor area (SMA), and cingulate motor area (CMA) of both hemispheres, as well as the relative activation intensity in these three regions of interest (ROIs) between the two hemispheres, denoted as the weighted laterality index (wLI). The Diffusion spectrum imaging (DSI) was used to assess the structural integrity of the posterior limb of internal capsule (PLIC) segment of the CSTLE. The integrity was indicated by calculating general fractional anisotropy of the PLIC segment of the CSTLE in the affected hemisphere (GFAPLIC_AH) in absolute term and by calculating the relative GFA of the PLIC (rGAFPLIC) between bilateral hemispheres in relative term. The associations of the two clinical measures (FMALE and TUGT) and the absolute and relative DSI (GFAPLIC_AH and rGAFPLIC) and fMRI measures (Σt values of bilateral SMC, SMA, and CMA activations, as well as wLI of SMC, SMA, and CMA activations) were first analyzed using the univariate linear regression analyses, controlling for age and post-onset time. Then, the multivariate linear regression analyses were performed to determine the relative contributions of the structural integrity of CSTLE and cortical activation patterns to FMALE and TUGT. Results: Univariate analyses showed that the FMALE score was moderately to highly correlated with two DSI measures, GFAPLIC_AH (R2= 0.392, p= 0.011) and rGFAPLIC (R2= 0.572, p= 0.001), and with two fMRI measures, Σt of SMC of the unaffected hemisphere (Σt SMC_UH) (R2= 0.619, p= 0.004) and wLISMC (R2= 0.389, p= 0.056). The TUGT performance was only strongly correlated with Σt of SMC of the affected hemisphere (Σt SMC_AH) (R2= 0.688, p= 0.004), Σt SMC_UH (R2= 0.545, p= 0.034), and Σt of CMA of the affected hemisphere (Σt CMA_AH) (R2= 0.610, p= 0.014), but not with DSI measures. Multivariate regression analyses showed that Σt SMC_UH (adjusted R2= 0.505, p= 0.004) was the only significant predictor for FMALE in the model using solely absolute DSI and fMRI measures and rGFAPLIC (adjusted R2= 0.486, p= 0.031) were the only significant predictor for FMALE in the model using solely relative DSI and fMRI measures. The Σt SMC_AH alone significantly predicted TUGT performance (adjusted R2= 0.595, p= 0.004). Discussion and Conclusions: Results of this study suggest that relative CST structural integrity measure and absolute SMC activation intensity measure in the unaffected hemisphere are the most important independent predictors for the lower extremity motor impairment level in patients with chronic patients. On the other hand, only the absolute SMC activation intensity in affected hemisphere was an independent predictor for functional mobility performance of these patients measured by TUGT. These findings suggest that different aspects of brain plasticity following stroke may contribute differentially to different dimensions of clinical motor performance.
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Roy, Francois D. "Associative plasticity and afferent regulation of corticospinal excitability in uninjured individuals and after incomplete spinal cord injury." Phd thesis, 2009. http://hdl.handle.net/10048/632.
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Cortical representations are plastic and are allocated based on the proportional use or disuse of a pathway. A steady stream of sensory input maintains the integrity of cortical networks; while in contrast, alterations in afferent activation promote sensorimotor reorganization. After an incomplete spinal cord injury (SCI), damage to the ascending and/or descending pathways induces widespread modifications to the sensorimotor system. Strengthening these spared sensorimotor pathways may be therapeutic by promoting functional recovery after injury.
Using a technique called transcranial magnetic stimulation (TMS), we show that the leg motor cortex is facilitated by peripheral sensory inputs via disinhibition and potentiation of excitatory intracortical circuits. Hence, in addition to its crucial role in sensory perception, excitation from peripheral sensory afferents can reinforce muscle activity by engaging, and possibly shaping, the activity of the human motor cortex. After SCI, the amount of excitation produced by afferent stimulation reaching the motor cortex is expectantly reduced and delayed. This reduction of sensory inflow to the motor cortex may contribute to our findings that cortical inhibition is down-regulated after SCI, and this compensation may aid in the recruitment of excitatory networks in the motor cortex as a result of the damage to its output neurons. By repeatedly pairing sensory inputs from a peripheral nerve in the leg with direct cortical activation by TMS, in an intervention called paired associative stimulation, we show that the motor system can be potentiated in both uninjured individuals and after SCI. In the uninjured subjects, we show that in order to produce associative facilitation, the time window required for coincident activation of the motor cortex by TMS and peripheral sensory inputs is not as narrow as previously thought (~100 vs. ~20 ms), likely due to the persistent activation of cortical neurons following activation by TMS. The potential to condition the nervous system with convergent afferent and cortical inputs suggests that paired associative stimulation may serve as a priming tool for motor plasticity and rehabilitation following SCI.
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Mehdibeigi, Roshanak. "The corticospinal and corticobulbar tracts : an animated three-dimensional instructional aid." 2004. http://edissertations.library.swmed.edu/pdf/MehdibeigiR081904/MehdibeigiRoshanak.pdf.
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Meneghelli, Pietro. "Intraoperative neurophysiology of the motor cortex and corticospinal tracts: advantages, limits and future perspectives." Doctoral thesis, 2020. http://hdl.handle.net/11562/1018728.
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Background. Brain surgery in motor areas requires a balance between radical surgical resection and risk of postoperative motor deficits. Intraoperative neurophysiological monitoring, especially with motor evoked potentials (MEPs), provides a valuable help in such conditions; however, the correlation between MEP amplitude changes and clinical outcome is not always clear. A stronger neurophysiological predictor of outcome is therefore desirable. Objectives. The aims of this Thesis are: a. to analyze the limits of MEP monitoring during brain surgery in motor areas with a special attention to the confounding factors that may alter the interpretation of MEP changes during surgery; b. to verify and confirm the role of a strong neurophysiological predictor of outcome - the D-wave monitoring - during surgery for intramedullary spinal cord tumor; c. to apply the D-wave monitoring during brain surgery in motor areas. The Thesis is divided in three sections according to the aforementioned objectives. Materials and Methods. In the first section, a consecutive cohort of 157 patients submitted to surgical removal of a tumour adjacent to the motor areas and CST with simultaneous subcortical motor mapping and DCS MEP monitoring were analysed. Motor function was assessed the day after surgery, at discharge, and at further follow-up postoperatively. A post-hoc analysis was conducted in order to analyse possible pre- and postoperative confounding factors during MEP changes interpretation. In the second section, a consecutive cohort of 219 patients submitted to surgery for intramedullary spinal cord tumors (ISCTs) with simultaneous muscle MEP and D-wave monitoring were analysed. Motor function was assessed the day after surgery, at discharge, and at further follow-up postoperatively. A post-hoc analysis was performed in order to verify the reliability of D-wave monitoring as a strong outcome predictor. In the third section, we report the experience of 3 consecutive cases operated on for brain tumors in motor areas with the aid of D-wave monitoring. Results. Section I: the location of the tumour in the prefrontal cortex and along the CST are related with a higher rate of postoperative motor deficits (p=0.04 and p=0.008, respectively); for tumours located in the prefrontal cortex, 53% of patients showed new motor deficit with changes of MEP in 16% of them. Different muscles showed different capability to predict new motor deficits; furthermore, the higher is the number of muscles with MEP amplitude below the threshold, the higher is the probability of a new stable motor deficit. Section II: D-wave monitoring is a valuable help during surgery for ISCTs and show a sensitivity of 33.3%, a specificity of 99.2%; positive predictive value is 50% and negative predictive value is 98.4%. The accuracy calculated is 97.6%. Section III: we were able to record TES D-wave in patients 2 and 3; in patient 1 we obtained the D-wave only with TES of the hemisphere contralateral to the tumour. It was not possible to obtain a clear D-wave from DCS in all three patients. In patients 2 and 3 it was possible to obtain the D-wave through subcortical bipolar stimulation along CST. Conclusions. Intraoperative neurophysiology is a valuable help during surgery in motor areas. MEP monitoring provide useful and reliable information during surgery, but it is not always easy to analyse the relationship between intraoperative changes and clinical outcome. D-wave monitoring is a well-known technique and our results confirmed its role of strong outcome predictor. The application of this technique for brain surgery can help to overcome the limits of MEP monitoring alone.
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HUANG, WEI-MIN, and 黃維民. "Cells of origin and sites of termination of corticospinal tracts in hamsters by HRP method." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/04166609695546983060.
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Beaulé-Bulman, Vincent. "Interactions interhémisphériques dans le contrôle du mouvement unilatéral." Thèse, 2017. http://hdl.handle.net/1866/19045.
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L’exécution d’un mouvement purement unilatéral nécessite le recrutement d’un vaste réseau de régions corticales et sous-corticales, qu’il est possible de regrouper sous le terme de réseau de transformation non-miroir. Ce réseau doit contrer la tendance naturelle du cerveau à exécuter des mouvements de manière bilatérale et synchronisée, en miroir. Malgré l’efficacité de ce réseau, une activité miroir subtile est observée au niveau de la main qui doit demeurer inactive lors de mouvements unilatéraux chez l'humain en santé. Ce débordement moteur doit être inhibé grâce aux interactions interhémisphériques transitant par le corps calleux (CC), la plus grande commissure du cerveau servant de pont entre les hémisphères. Ainsi, la commande motrice peut être acheminée efficacement du cortex moteur primaire (M1) controlatéral à la main devant exécuter une l’action par l’entremise de la voie corticospianle (VCS). En plus du CC, le cortex prémoteur (CPM) joue un rôle important dans ce réseau puisque son interférence via la stimulation magnétique transcrânienne (SMT) entraîne une augmentation de l’activité miroir dans la main devant normalement demeurer inactive lors d’un mouvement unilatéral. Ainsi, toute modification dans ce réseau ou dans les processus interhémisphériques peut provoquer l’augmentation des mouvements miroirs (MM). À ce jour, aucune étude n’a tenté de moduler ces interactions pour réduire la présence de MM.
Ainsi, les études cliniques et méthodologiques qui composent la présente thèse comportent deux objectifs principaux : (1) déterminer si la stimulation électrique transcrânienne à courant direct (SÉTcd) permet l'étude du réseau de transformation non-miroir, et si cette technique est en mesure de diminuer l’intensité des MM chez des individus en santé; (2) caractériser l'anatomie et le fonctionnement du cerveau dans deux populations d’individus porteurs de mutations génétiques affectant le développement de structures impliquées dans la latéralisation du mouvement, le CC et la VCS.
L’article 1 décrit les assisses théoriques de la présente thèse grâce à une revue de la littérature portant sur les interactions interhémisphériques dans le mouvement unilatéral.
L’article 2 suggère que la SÉTcd est un outil efficace dans l'étude du réseau de transformation non-miroir puisque le protocole de stimulation bilatérale a permis d’augmenter la présence et l’intensité des MM physiologiques (MMp) chez des individus en santé. Cependant, il n’a pas été possible de moduler à la baisse les MMp malgré différents protocoles de stimulation.
Dans l’article 3, l'étude d’individus nés sans CC a mis en lumière une augmentation de l’épaisseur corticale au niveau des aires somatosensorielles (S1) et visuelles (V1) primaires, de même qu’au niveau de la représentation de la main dans M1. Ces différences demeurent toutefois légères considérant l’importance du CC.
L’article 4 a démontré que les individus porteurs d’une mutation sur le gène DCC présentent un phénotype similaire à celui de porteurs d'une mutation sur le gène RAD51. Ces mutations affectent la migration de la VCS au niveau des pyramides. La VCS projette ainsi aux deux mains, causant des mouvements miroirs congénitaux (MMC). Cette pathologie est également accompagnée d’anomalies neurophysiologiques, telle qu’une inhibition interhémisphérique (IIH) réduite.
En somme, les études composant cette thèse ont permis d’approfondir notre connaissance de certaines structures responsables de la latéralisation adéquate du mouvement, tout en décrivant de nouvelles méthodes pour en étudier le fonctionnement.The execution of purely unilateral hand movements requires the recruitment of vast cortical and subcortical brain areas known as the non-mirroring network. This network counteracts the natural tendency of the brain, which tends to execute movements in a bilateral and synchronized manner. Despite the efficacy of the non-mirroring network in restricting motor output to contralateral limbs, subtle mirroring can be observed in the inactive hand of healthy individuals when performing a unilateral task. This motor overflow needs to be inhibited through interhemispheric projections coursing through the corpus callosum (CC), the biggest white matter tract of the brain. This mechanism makes it possible for motor commands originating from the primary motor cortex (M1) to reach the contralateral hand performing an action via the corticospinal tract (CST). It has been suggested that the premotor cortex (PMC) is an important component of the non-mirroring network since its interference with transcranial magnetic stimulation (TMS) enhances mirror activity in the inactive, mirror hand when a unilateral hand movement is performed. Indeed, modulation of parts of the non-mirroring network and interhemispheric projections can result in enhanced mirror movements (MM). It is not known whether specific interventions can decrease MM. The clinical and methodological studies that compose the present thesis have two main objectives: (1) Determine whether transcranial direct-current stimulation (tDCS) can be used to assess non-mirroring network function and reduce MM intensity in healthy individuals; (2) Characterize brain function and anatomy in two clinical populations presenting specific genetic mutations that affect the development of structures involved in the lateralization of movement (the CC and CST). Article 1 provides a theoretical basis for the present essay through a review of the literature pertaining to interhemispheric interactions in the production of unilateral movements. Article 2 shows that tDCS can be used to study the non-mirroring network since a bilateral stimulation protocol significantly increased the intensity of physiological MM (pMM) in healthy individuals. However, despite different stimulation protocols, it was not possible to reduce pMM. In article 3, anatomical MRIs performed in individuals born without a CC revealed increases in cortical thickness in primary somatosensory (S1) and visual (V1) cortex, as well as in the hand representation of M1. Taken together, however, the data suggest that anatomical differences between acallosal patients and healthy participants are relatively subtle considering the size and function of the CC. Article 4 showed that individuals presenting a mutation on the DCC gene display a phenotype similar to that of individuals presenting a mutation on the RAD51 gene. DCC mutations affect the crossing of the CST at the pyramidal level, resulting in a CST that projects to both hands simultaneously, causing congenital mirror movements (CMM). This pathological condition is accompanied by neurophysiological anomalies that include reduced interhemispheric inhibition (IHI). In summary, the studies comprised in the present thesis significantly increase our knowledge of the specific brain structures that enable the proper lateralization of movements. It also describes novel methods that can be used to investigate the non-mirroring network.
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Chang, Ting-Tzu, and 張庭慈. "Roles of the Corticostriatal Tracts and Corticospinal Tracts in Short-term Ankle Tracking Learning in Patients with Chronic Stroke and Healthy Adults: A Diffusion Spectrum Imaging Study." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/gf773j.
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碩士國立臺灣大學
物理治療學研究所
105
Background and Purpose: Motor learning ability is crucial for individuals to learn new skills in order to adapt to environmental changes throughout the lifespan. Many fMRI studies have found that functional brain activations in different frontal cortical regions and the striatum are relevant to different stages of visuomotor learning. However, little is known about how the structural connectivity between these learning-related regions, in particular, the corticostriatal tracts and the corticospinal tracts, contributes to learning an ankle tracking task. Methods: Twenty-one patients with chronic stroke (age= 62.2±8.5 yr, male: 16, female: 5) and 26 age-matched healthy adults (age= 62.0±8.1 yr, male: 7, female: 19) participated in this study. Using a custom-built ankle tracking assessment and training device, all participants underwent a short-term ankle tracking learning paradigm for 5 consecutive practice sessions within 5 days, followed by a 2-day retention interval and a Week 1 retention test. Repeated and random sequences were both practiced in the 5 days. Tracking performance was measured by using root mean squared error (RMSE). Clinical assessments, ankle tracking performance, and diffusion spectrum MR image (DSI) of the brain were obtained at Baseline test and Week 1 retention test. Tract-specific tractography analysis were used to reconstruct bilateral dorsolateral prefrontal cortex-caudate (dlPFC-caudate), supplementary motor area-putamen (SMA-putamen), and corticospinal tracts (CSTs). Tract integrity was indexed by using generalized fractional anisotropy (GFA) of DSI. Separate partial correlation analyses were performed to evaluate relationships between white matter tract integrity and tracking performance or improvement after learning. Results: Both healthy and stroke subjects significantly improved tracking accuracy over time, regardless of sequences (p< 0.001 both). Among the investigated white matter tracts, no change in tract integrity was found for each tract from baseline to Week 1 retention test (p> 0.05 of each tract). Separate partial correlations showed that, in the healthy group, GFAB_CST_contra was associated with RMSEB_rep (r= 0.423, p= 0.035) and RMSEB_ran (r= 0.456, p= 0.022); GFAW1_SMA_contra was associated with ∆RMSEB-W1_ran at a significant level (r= -0.411, p= 0.041) and with ∆RMSEB-W1_rep at a marginal level (r=-0.393, p=0.052). However, there were no significant correlations between baseline integrity of the contralateral dlPFC-caudate tract and the performance improvement under repeated (r= -0.189, p= 0.386) and random sequence tracking conditions (r= -0.157, p= 0.453) after short-term learning for healthy subjects. In the stroke group, GFAB_CST_contra was associated with ∆RMSEB-W1_rep (r= 0.536, p= 0.018); GFAW1_CST_contra was associated with ∆RMSEB-W1_ran (r= 0.520, p= 0.023). Discussion and conclusions: Both healthy adults and hemiparetic patients with chronic stroke could learn this ankle tracking task. Although we did not find motor learning-related structural changes of the investigated white matter tracts after such as short-term learning, the integrity of specific white matter tracts were found to be closely linked to performance outcomes or gains. In particular, different structural brain mechanisms were found to be related to learning a novel ankle visuomotor task between healthy adults and patients with chronic stroke. For healthy adults, the SMA-putamen tract was closely associated with ankle tracking learning, whereas in patients with stroke, the CST played an important role in such learning.
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Luo, Zheng-An, and 羅政安. "Structure Integrity of the Corticospinal Tracts Relates to the Motor Function of the Affected Lower Extremity in Stroke with Subcortical Infarction." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/94435480165566179538.
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碩士國立臺灣大學
物理治療學研究所
96
Backgrond and Purposes：This study aimed to find the differences of the structural integrity of bilateral corticospinal tracts (CST) between persons with subcortical infarction at the mid- and long-term durations after stroke (< 20-30 days (D30), 90th day (D90) and 180th day (D180)) and healthy adults, the changes of structural integrity in stroke group between the three times, and the relationships between the integrity of the affected CST and the motor function of the affected lower extremity. Methods：Five hemiplegic patients (63.1 ± 5.6 yrs) received clinical assessments and the diffusion spectrum imaging (DSI) scan at D30, D90 and D180, respectively. The motor function of the affected lower extremity was evaluated for each patient by the lower-extremity motor part of the Fugl-Meyer Assessment scale (FMA-LE). Five healthy adults who matched stroke with age, gender and footedness (64.3 ± 4.2 yrs) received clinical assessments and the DSI scan one time. For DSI data analysis, the generalized fractional anisotropy (GFA) and the relative GFA (rGFA) values of different segments (cerebral peduncle (CP), internal capsule (IC), above IC and above CP for both groups; below lesion, lesion and above lesion for stroke group only) of bilateral CSTs were calculated by tract-specific (TS) quantitative analysis for each subject. We also used the traditional region of interest (ROI) analysis to calculate the GFA and the rGFA values of bilateral posterior limb of the internal capsule (PLIC) for each subject so that we could understand the validity of the GFA and rGFA values by TS analysis. Independent t test was applied for comparions of the GFA and rGFA values between stroke and healthy groups. Two-way (hemisphere x post-stroke day) repeated measures of ANOVA was used to investigate differences in the GFA values of different segments of bilateral CSTs by TS analysis and those by ROI analysis between the three testing times. One-way (post-stroke day) repeated measures of ANOVA was used to investigate differences in the rGFA values of the CST by TS analysis and those by ROI analysis between the three testing times. Spearman correlation coefficient was used for the correlations between these GFA and rGFA values with the FMA-LE at three testing times concurrently and the correlations between these GFA and rGFA values at D30 and D90 with the FMA-LE at D90 and D180, respectively. Results：The GFA and rGFA values by TS analysis highly related to those by ROI analysis in stroke at all three testing times (r= 0.6-0.9). The GFA values of the affected CST in stroke at all three testing time, except the CP and IC segments at D180 were significantly lower than those of bilateral CSTs in healthy adults (p< 0.05), but the GFA values of the unaffected CST were the same as those of healthy adults (p> 0.05). Only the rGFA values of the IC segment at D30 and D90 in stroke were higher than those in healthy adults (p< 0.05). The GFA and the rGFA values of above lesion and above CP segments of the affected CST of the stroke changed between different testing times (p< 0.05). The rGFA value of the IC segment of the CST by TS analysis and by ROI analysis at D30 highly related to the FMA-LE at D90 and D180, respectively (r= -0.894, p= 0.041). The GFA and rGFA values of the lesion segment and the GFA value of the IC segment of the affected CST by TS analysis at D90 highly related to the FMA-LE at D90 and D180, respectively (r= 0.894, -0.894 and 0.894, p= 0.041). Discussion and Conclusions：The results indicate that the GFA and rGFA values by TS analysis have high validity due to high correlations between those values by TS analysis and by ROI analysis. Structural integrity of the affected CST highly relates to the motor function of the affected lower extremity concurrently and predictively. No significant change of structural integrity of the lesion segment of the affected CST was found due to different trends between patients with better motor recovery and those with poor recovery. In future, we can measure the test-retest reliability of the integrity in healthy adults, and find relationships between integrity of the affected CST and motor functions of the affected upper extremity in stroke and the differences of the changes between stroke with different severity.