Littérature scientifique sur le sujet « Uncinate fasciculu »
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Articles de revues sur le sujet "Uncinate fasciculu"
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Peltier, Johann, Sébastien Verclytte, Christine Delmaire, Jean-Pierre Pruvo, Olivier Godefroy et Daniel Le Gars. « Microsurgical anatomy of the temporal stem : clinical relevance and correlations with diffusion tensor imaging fiber tracking ». Journal of Neurosurgery 112, no 5 (mai 2010) : 1033–38. http://dx.doi.org/10.3171/2009.6.jns08132.
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Object The authors used a fiber dissection technique to describe the temporal stem and explain the tendency of malignant tumors to spread within both the frontal and temporal lobes. The authors focused on the morphological characteristics and course of various fasciculi of the temporal stem, including the uncinate fascicle, occipitofrontal fascicle, anterior commissure, loop of the optic radiations (Meyer loop), and the ansa peduncularis. Methods Eight previously frozen, formalin-fixed human brains were dissected under an operating microscope using the fiber dissection technique described by Klingler. Lateral, inferior, and medial approaches were made. Cross-sectional 3D MR images obtained in 10 patients without brain lesions demonstrated that fibers of the temporal stem, which were intermingled together in various ways, curved laterally within the basal forebrain. Various pathological entities affecting the temporal stem are described and discussed. Results The uncinate fascicle has 3 portions: a ventral extension, an intermediary segment called the isthmus, and a dorsal segment. The inferior occipitofrontal fasciculus is a layer of more superficial white matter that appeared to be superior to the uncinate fasciculus. A short ventral portion of the radiations of the corpus callosum was sometimes noted to run ventrally to enter the temporal stem and to reach both temporal lobes. Conclusions To the authors' knowledge, a detailed anatomy of the temporal stem has not been previously described in the literature. The unique anatomy of the temporal stem provides a route for tumor spread between the frontal and temporal lobes.
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David, Szabolcs, Lieke Heesink, Elbert Geuze, Thomas Gladwin, Jack van Honk, Rolf Kleber et Alexander Leemans. « Regions of white matter abnormalities in the arcuate fasciculus in veterans with anger and aggression problems ». Brain Structure and Function 225, no 4 (27 décembre 2019) : 1401–11. http://dx.doi.org/10.1007/s00429-019-02016-2.
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AbstractAggression after military deployment is a common occurrence in veterans. Neurobiological research has shown that aggression is associated with a dysfunction in a network connecting brain regions implicated in threat processing and emotion regulation. However, aggression may also be related to deficits in networks underlying communication and social cognition. The uncinate and arcuate fasciculi are integral to these networks, thus studying potential abnormalities in these white matter connections can further our understanding of anger and aggression problems in military veterans. Here, we use diffusion tensor imaging tractography to investigate white matter microstructural properties of the uncinate fasciculus and the arcuate fasciculus in veterans with and without anger and aggression problems. A control tract, the parahippocampal cingulum was also included in the analyses. More specifically, fractional anisotropy (FA) estimates are derived along the trajectory from all fiber pathways and compared between both groups. No between-group FA differences are observed for the uncinate fasciculus and the cingulum, however parts of the arcuate fasciculus show a significantly lower FA in the group of veterans with aggression and anger problems. Our data suggest that abnormalities in arcuate fasciculus white matter connectivity that are related to self-regulation may play an important role in the etiology of anger and aggression in military veterans.
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Ribbeck Lourdes, Simbrón, Sandoval Paredes Josefina, Amador Sánchez Karen et Taboada Barajas Jesús. « Uncinate Fasciculus in Temporal Lobe Epilepsy ». Brain and Neurological Disorders 2, no 2 (7 octobre 2019) : 01–04. http://dx.doi.org/10.31579/2642-973x/010.
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Background and purpose: Temporal lobe epilepsy is the most common focal intractable epilepsy. Uncinate fasciculus is a white fiber bundle that connects the orbitofrontal cortex with the anterior temporal lobe, and is implicated in most of the superior mental functions. There is evidence of uncinate fasciculus as a propagation pathway of seizures from temporal lobe. The aim of the study is to determine uncinate fasciculus alterations in patients with temporal lobe epilepsy, through fractional anisotropy. Methods: Thirty-three patients with temporal lobe epilepsy (10 right and 23 left) were studied. All of them were right-handed and had left hemisphere dominance for language. A 1.5 T MR imaging scanner was used to obtain diffusion tensor imaging (DTI). Fractional anisotropy of uncinate fasciculus was calculated through TBSS (Tract Based Spatial Statistics). Statistical analysis was done using IBM SPSS (v. 25). Results: Fractional anisotropy was higher in right uncinate fasciculus, regardless of epilepsy side. Right uncinate fasciculus, at the insula level, showed lower fractional anisotropy in patients with right temporal lobe epilepsy. Conclusions: Results support the evidence of uncinate fasciculus as a pathway of propagation in temporal lobe epilepsy, specially at insular level.
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Foley, Sonya F., Matthew Bracher-Smith, Katherine E. Tansey, Judith R. Harrison, Greg D. Parker et Xavier Caseras. « Fractional anisotropy of the uncinate fasciculus and cingulum in bipolar disorder type I, type II, unaffected siblings and healthy controls ». British Journal of Psychiatry 213, no 3 (21 juin 2018) : 548–54. http://dx.doi.org/10.1192/bjp.2018.101.
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BackgroundFractional anisotropy in the uncinate fasciculus and the cingulum may be biomarkers for bipolar disorder and may even be distinctly affected in different subtypes of bipolar disorder, an area in need of further research.AimsThis study aims to establish if fractional anisotropy in the uncinate fasciculus and cingulum shows differences between healthy controls, patients with bipolar disorder type I (BD-I) and type II (BD-II), and their unaffected siblings.MethodFractional anisotropy measures from the uncinate fasciculus, cingulum body and parahippocampal cingulum were compared with tractography methods in 40 healthy controls, 32 patients with BD-I, 34 patients with BD-II, 17 siblings of patients with BD-I and 14 siblings of patients with BD-II.ResultsThe main effects were found in both the right and left uncinate fasciculus, with patients with BD-I showing significantly lower fractional anisotropy than both patients with BD-II and healthy controls. Participants with BD-II did not differ from healthy controls. Siblings showed similar effects in the left uncinate fasciculus. In a subsequent complementary analysis, we investigated the association between fractional anisotropy in the uncinate fasciculus and polygenic risk for bipolar disorder and psychosis in a large cohort (n= 570) of healthy participants. However, we found no significant association.ConclusionsFractional anisotropy in the uncinate fasciculus differs significantly between patients with BD-I and patients with BD-II and healthy controls. This supports the hypothesis of differences in the physiological sub-tract between bipolar disorder subtypes. Similar results were found in unaffected siblings, suggesting the potential for this biomarker to represent an endophenotype for BD-I. However, fractional anisotropy in the uncinate fasciculus seems unrelated to polygenic risk for bipolar disorder or psychosis.Declaration of interestNone.
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Coppens, Jeroen R., Kelly B. Mahaney et Saleem I. Abdulrauf. « An anteromedial approach to the temporal horn to avoid injury to the optic radiation fibers and uncinate fasciculus : anatomical and technical note ». Neurosurgical Focus 18, no 6 (juin 2005) : 1–6. http://dx.doi.org/10.3171/foc.2005.18.6.16.
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Object The aim of this study was to define an anteromedial approach to the temporal horn via a transsylvian approach to avoid injury to the optic radiation fibers as well as the uncinate fasciculus. This route was compared with standard surgical approaches to the temporal horn, and their relationship to the optic radiation and uncinate fasciculus was reviewed. Methods Three cadaveric brain specimens were prepared with freezing and thawing cycles according to the Klingler technique. Dissection was performed in a lateral-to-medial fashion with the help of wooden spatulas. Photographs were taken through the operating microscope at every level of the dissection. The dissection was continued until the optic radiation was encountered. Particular attention was paid to the relationship of the uncinate fasciculus with the optic radiation. An anteromedial transsylvian approach was defined to enter the temporal horn without injuring the optic radiation or the uncinate fasciculus. Conclusions A transsylvian anteromedial approach through the pyriform cortex at the level of the anterior and superior surface of the uncus enables a safe entry into the temporal horn without injury to the optic radiation fibers or the main part of the uncinate fasciculus.
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Incekara, Fatih, Djaina Satoer, Evy Visch-Brink, Arnaud Vincent et Marion Smits. « Changes in language white matter tract microarchitecture associated with cognitive deficits in patients with presumed low-grade glioma ». Journal of Neurosurgery 130, no 5 (mai 2019) : 1538–46. http://dx.doi.org/10.3171/2017.12.jns171681.
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OBJECTIVEThe authors conducted a study to determine whether cognitive functioning of patients with presumed low-grade glioma is associated with white matter (WM) tract changes.METHODSThe authors included 77 patients with presumed low-grade glioma who underwent awake surgery between 2005 and 2013. Diffusion tensor imaging with deterministic tractography was performed preoperatively to identify the arcuate, inferior frontooccipital, and uncinate fasciculi and to obtain the mean fractional anisotropy (FA) and mean diffusivity per tract. All patients were evaluated preoperatively using an extensive neuropsychological protocol that included assessments of the language, memory, and attention/executive function domains. Linear regression models were used to analyze each cognitive domain and each diffusion tensor imaging metric of the 3 WM tracts.RESULTSSignificant correlations (corrected for multiple testing) were found between FA of the arcuate fasciculus and results of the repetition test for the language domain (β = 0.59, p < 0.0001) and between FA of the inferior frontooccipital fasciculus and results of the imprinting test for the memory domain (β = −0.55, p = 0.002) and the attention test for the attention and executive function domain (β = −0.62, p = 0.006).CONCLUSIONSIn patients with glioma, language deficits in repetition of speech, imprinting, and attention deficits are associated with changes in the microarchitecture of the arcuate and inferior frontooccipital fasciculi.
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Burns, J., D. Job, M. E. Bastin, H. Whalley, T. Macgillivray, E. C. Johnstone et S. M. Lawrie. « Structural disconnectivity in schizophrenia : a diffusion tensor magnetic resonance imaging study ». British Journal of Psychiatry 182, no 5 (mai 2003) : 439–43. http://dx.doi.org/10.1192/bjp.182.5.439.
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BackgroundThere is growing evidence that schizophrenia is a disorder of cortical connectivity Specifically, frontotemporal and frontoparietal connections are thought to be functionally impaired. Diffusion tensor magnetic resonance imaging (DT–MRI) is a technique that has the potential to demonstrate structural disconnectivity in schizophrenia.AimsTo investigate the structural integrity of frontotemporal and frontoparietal white matter tracts in schizophrenia.MethodThirty patients with DSM–IV schizophrenia and thirty matched control subjects underwent DT–MRI and structural MRI. Fractional anisotropy – an index of the integrity of white matter tracts – was determined in the uncinate fasciculus, the anterior cingulum and the arcuate fasciculus and analysed using voxel-based morphometry.ResultsThere was reduced fractional anisotropy in the left uncinate fasciculus and left arcuate fasciculus in patients with schizophrenia compared with controls.ConclusionsThe findings of reduced white matter tract integrity in the left uncinate fasciculus and left arcuate fasciculus suggest that there is frontotemporal and frontoparietal structural disconnectivity in schizophrenia.
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Charlton, R. A., M. Lamar, A. Zhang, S. Yang, O. Ajilore et A. Kumar. « White-matter tract integrity in late-life depression : associations with severity and cognition ». Psychological Medicine 44, no 7 (16 septembre 2013) : 1427–37. http://dx.doi.org/10.1017/s0033291713001980.
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BackgroundAlthough significant changes in both gray and white matter have been noted in late-life depression (LLD), the pathophysiology of implicated white-matter tracts has not been fully described. In this study we examined the integrity of specific white-matter tracts in LLD versus healthy controls (HC).MethodParticipants aged ⩾60 years were recruited from the community. The sample included 23 clinically diagnosed individuals with LLD and 23 HC. White-matter integrity metrics [fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD)] were calculated in the bilateral cingulum and uncinate fasciculus. Depression severity was measured using the Center for Epidemiological Studies Depression Scale (CESD). Composite scores for learning and memory and executive function were created using standardized neuropsychological assessments.ResultsWhite-matter integrity was lower in LLD versus HC in the bilateral cingulum and right uncinate fasciculus (p⩽0.05). In the whole sample, depression severity correlated with integrity in the bilateral cingulum and right uncinate fasciculus (p ⩽0.05). In patients, depression severity correlated with the integrity of the left uncinate fasciculus (p = 0.03); this tract also correlated with executive function (p = 0.02). Among HC, tract integrity did not correlate with depression scores; however, learning and memory correlated with integrity of the bilateral uncinate fasciculus and bilateral cingulum; executive function correlated with the right uncinate and left cingulum (p ⩽0.05).ConclusionsWhite-matter tract integrity was lower in LLD than in HC and was associated with depression severity across all participants. Tract integrity was associated with cognition in both groups but more robustly among HC.
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Villegas Martínez, J. L., J. A. Blanco Garrote, F. Uribe Ladrón de Cegama, B. Arribas Simón et G. Cabús Piñol. « Diffusion tensor imaging (DTI) findings in schizophrenia : A review ». European Psychiatry 26, S2 (mars 2011) : 960. http://dx.doi.org/10.1016/s0924-9338(11)72665-7.
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IntroductionDiffusion tensor imaging (DTI) is a magnetic resonance imaging technique that have increasingly being used for the non-invasive evaluation of brain white matter (WM) abnormalities. Several studies suggest that the normal integration of cerebral function may be compromised in schizophrenia. Abnormalities in WM tracts may be directly relevant for the neuropathology of schizophrenia.ObjetivesThe purpose of this review was to discuss recent DTI findings in schizophrenia and a methodologic analysis.MethodsThe literature search was performed with the search engine PubMed of the U.S. National Library of Medicine. Search strategy used was based on the Cochrane review technique, limited to the period between 1998 (first report on DTI and schizophrenia) and May 2010. And limited to ‘Title/Abstract’. The reference lists of these studies were used to identify additional studies.ResultsThere is a striking amount of heterogeneity in findings, probably by methodologic problems. Brain regions such as the cingulate bundle, corpus callosum, and regions within frontal and temporal WM have a proportionally larger number of positive findings across the studies. In addition, WM tracts as The superior longitudinal fasciculus, fronto-occipital longitudinal fasciculi, uncinate fasciculi, frontal longitudinal fasciculus and the arcuate fasciculus have also positive findings in patients with schizophrenia. Other brain structures as the cerebellar peduncles, the fornix, the hippocampus and parahippocampal gyrus, the thalamic and optic radiations have been evaluated and shown positive findings. However, these findings are not present in all studies. DTI abnormalities in first-episode patients are less robust than in chronic patients.ConclusionsRecent DTI findings further support the hypothesis of structural dysconnectivity in schizophrenia.
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Sundram, F., Q. Deeley, S. Sarkar, E. Daly, R. Latham, G. J. Barker et D. G. M. Murphy. « P02 - 361 White matter microstructural abnormalities in antisocial personality disorder : A pilot diffusion tensor imaging study ». European Psychiatry 26, S2 (mars 2011) : 957. http://dx.doi.org/10.1016/s0924-9338(11)72662-1.
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IntroductionAntisocial personality disorder (ASPD) and psychopathy involve significant interpersonal and behavioural impairments. However, little is known about white matter (WM) abnormalities in tracts linking grey matter regions. A previous diffusion tensor imaging (DT-MRI) tractography study in ASPD and psychopathy revealed abnormalities in the right uncinate fasciculus, indicating fronto-limbic disconnectivity.ObjectivesIt is not clear whether WM abnormalities are restricted to only this tract or are more widespread. Therefore, we planned to use whole brain DT-MRI voxel-based analyses.AimsTo clarify if WM abnormalities extend beyond the frontal lobe.MethodsWe used whole brain DT-MRI to compare WM fractional anisotropy (FA) of 15 adults with ASPD and healthy age, handedness and IQ-matched controls. Also, within ASPD subjects, we related differences in FA to severity of psychopathy measures.ResultsSignificant WM FA reductions were found in ASPD subjects relative to controls. These were found bilaterally in the anterior corpus callosum. Right hemisphere FA reduction was found in the anterior corona radiata, uncinate fasciculus, inferior fronto-occipital fasciculus and internal capsule. Left hemisphere, FA deficits encompassed the inferior longitudinal fasciculus, inferior fronto-occipital fasciculus and internal capsule. There was a significant negative correlation between WM FA in the right uncinate fasciculus and corpus callosum and measures of psychopathy.ConclusionsWe report FA reduction in the uncinate fasciculus and anterior corpus callosum which may be associated with frontal and inter-hemispheric disconnectivity in ASPD, in addition to abnormalities in other tracts which directly or indirectly connect to prefrontal regions.
Thèses sur le sujet "Uncinate fasciculu"
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CASAROTTI, ALESSANDRA. « Nomi propri, categorie semantiche, parole astratte e concrete : correlati neurali in pazienti con glioma cerebrale ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/40214.
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Several studies have suggested different neural circuits for different categories of stimuli. The present studies explore in patients submitted to surgical removal of a glioma, the role of cortical and subcortical structures involved in processing abstract and concrete words. In the first study living and non-living objects were investigated. Direct electrical cortical stimulation was used to map naming of living/non-living entities during surgical removal, then subcortical connections for specific categories of objects were investigated. Two different pathways were identified, one for living and one for non-living things. These results constitute a neurophysiological evidence for the critical role of subcortical pathways as part of the neural circuits that represent lexical-conceptual knowledge of different categories of objects.
The second study focused on proper names retrieval and its relationship with the uncinate fasciculus. Forty-four patients with a brain tumor in the left frontal or temporal lobe were examined. In 18 of them surgical removal included the uncinate fasciculus. Patients were assessed before surgery, three-seven days after surgery and three months after surgery. This procedure allowed understanding whether there was any difference due to the lesion of uncinate fasciculus. Patients with removal of the uncinate fasciculus were impaired in naming famous faces and objects. In the third study processing of abstract and concrete nouns was investigated. Fifty-six patients with a brain tumor in the left and right frontal or temporal lobe were examined by means of a semantic similarity judgment. The results suggest that the anterior temporal and the left fronto-insular regions are involved in processing abstract words.
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di, GIACOMO ESTER. « Antisocial Personality Disorder and Psichopathy : are they really a continuum ? Anatomical and Functional differences and the role of the Uncinate Fasciculus ». Bachelor's thesis, Università degli Studi di Milano Bicocca, 2014. http://hdl.handle.net/10281/89423.
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Bhatia, Kartik Dev. « Diffusion tensor imaging of the uncinate fasciculus in mood and psychotic disorders ». Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20328.
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Background: The uncinate fasciculus (UF) is the largest white matter association tract connecting the prefrontal cortex and the medial temporal lobe, and is the final major association tract to mature with myelination extending into the third decade of life. The UF is typically described as having a temporal stem, a body, and two prefrontal stems extending to the lateral and fronto-polar prefrontal cortex respectively. However, there is increasing evidence of fibers extending from the subgenual cingulate gyrus (Brodmann Area 25: BA25) to the amygdala, along the expected course of the UF. If these fibers are continuous with the UF, they may represent a separate medial subgenual stem. BA25 is implicated in mood disorder pathophysiology, whilst the lateral prefrontal cortex is implicated in the negative symptoms of psychosis. Hypotheses: Given that the UF as a whole has reduced integrity in both mood and psychotic disorders, it is feasible that the lateral stem of the UF is more markedly affected in psychosis and the potential subgenual stem more markedly affected in depression. In addition, since the UF matures during the typical clinical onset age of these disorders, we hypothesize that such changes are present from first onset. Methods: In a series of four manuscripts utilizing diffusion tensor imaging (DTI), the anatomy, anatomical variability, and stem-by-stem microstructural changes in depression and first-onset psychosis patients were investigated within the UF. The use of a stem-by-stem analysis within the UF was a common link across the four articles. Results: A subgenual stem of the UF was consistently demonstrated. Significantly reduced integrity was shown in the subgenual and polar stems of the UF in depressed patients (in both the first-onset and chronic depression cohorts), and in the lateral and polar stems in first-onset psychosis patients. Conclusion: We have demonstrated anatomically distinct patterns of white matter changes within the uncinate fasciculus in mood vs. psychotic disorders, present from the time of first clinical onset.
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Hiyoshi-Taniguchi, Kazuko. « The Uncinate Fasciculus as a Predictor of Conversion from aMCI to Alzheimer Disease ». Kyoto University, 2015. http://hdl.handle.net/2433/199198.
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Fujie, Saori. « The Role of the Uncinate Fasciculus in Memory and Emotional Recognition in Amnestic Mild Cognitive Impairment ». Kyoto University, 2010. http://hdl.handle.net/2433/120563.
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Umapathy, Lavanya, et Lavanya Umapathy. « Assessment of White Matter Integrity in Bonnet Macaque Monkeys using Diffusion-weighted Magnetic Resonance Imaging ». Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/622837.
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Diffusion-weighted magnetic resonance imaging (dMRI) has been used to non-invasively investigate the integrity of white matter and the connectivity of the brain. In this work, high angular resolution diffusion imaging (HARDI), an advanced dMRI methodology was developed and employed in bonnet macaque monkeys to study the connectivity of the orbitofrontal cortex (OFC) and amygdala, two gray matter regions involved in making reward-guided decisions. With age, it is believed that there is a decline in the white matter connectivity between these two regions, also known as uncinate fasciculus (UF), and that this affects reward-value assignment and feedback learning in older adults. The analysis pipeline involved correction for distortions due to eddy currents and field inhomogeneity, noise reduction using a local principal component analysis based technique and subsequent registration to the high-resolution T1-weighted images. Gray matter regions corresponding to OFC and amygdala were identified on the T1-weighted images and probabilistic tractography was carried out to delineate the tracts belonging to UF. The output connectivity map from tractography was used to extract imaging parameters of interest such as fractional anisotropy, axial and radial diffusivity along the UF. A significant reduction in the fractional anisotropy index and the axial diffusivity index along the UF tract was observed with increased age of monkeys. Compared to the left hemisphere, stronger trends were observed in the right hemisphere of the monkeys, indicating possible laterality.
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Hau, Janice. « Atlasing white matter pathways using diffusion magnetic resonance imaging (dMRI) : With a focus on human association tracts in the external and extreme capsules ». Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0353/document.
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Il est de plus en plus reconnu que les connexions du cerveau jouent un rôle important sur la fonction cérébrale, en particulier les fonctions cognitives supérieures comme le langage. Cependant l’imperfection des techniques traitant les connexions macroscopiques humaines a empêché l’avancement de nos connaissances sur l'anatomie des faisceaux. Nous nous appuyons ainsi aujourd’hui essentiellement sur la littérature du XIXème siècle. Les définitions des trajets et des connexions anatomiques de nombreux faisceaux sont constamment débattues. En utilisant l'imagerie de diffusion, nous réévaluons les anatomies des faisceaux clés dans une grande cohorte saine. Nous utilisons une nouvelle approche de segmentation des faisceaux qui vise à reproduire la méthode introduite par les dissectionistes. Celle-ci définit un tract comme l’ensemble des fibres passant par une même tige, minimisant ainsi l’a priori sur leurs terminaisons. Nous nous concentrons sur les faisceaux d'association des capsules externe et extrême, notamment les faisceaux occipito-frontal inférieur (FOFI) et unciné (FU) impliqués dans le circuit du langage ventral. Nous passons en revue la littérature sur ces tracts, fournissons des descriptions détaillées de leurs connectivités anatomiques et donnons un nouvel éclairage sur leur asymétrie et organisation interne. Dans une première étude, nous confirmons que les deux faisceaux ont de plus vastes projections dans le cortex qu'on ne le pensait, et nous présentons de nouveaux résultats concernant les branches asymétriques des faisceaux. Dans une deuxième étude, nous étudions en profondeur le FU et ses sous composantes. Nous résolvons un débat d’un siècle en exhibant clairement sa frontière avec le FOFI et nous identifions pour chaque sous composante des caractéristiques anatomiques distinctives y compris des asymétries. Ces résultats apportent un éclairage nouveau sur le FOFI et le FU qui sera crucial pour démêler leurs rôles multifonctionnelsThe importance of the brain’s connections for cerebral function is increasingly emphasized especially for higher cognitive functions like language. But the imperfection of the techniques used to address the human macroscopic connections has prevented the advancement of our knowledge on the anatomy of fibre pathways. Thus we rely heavily on XIXth century literature. Controversy surrounding the anatomical course and connections of many fibre pathways persists. Using diffusion imaging, we reevaluate the anatomies of key pathways in a large healthy cohort. We use a novel tract segmentation approach that aims to reproduce the method introduced by dissectionists – defining a tract as all fibers passing through a stem, thus minimizing a priori on their terminations. We focus on the association pathways of the external and extreme capsules, namely the inferior fronto-occipital (IFOF) and uncinate fasciculi (UF), implicated in the ventral language circuitry. We review the literature on these tracts, provide detailed descriptions of their connectional anatomies and present new insights regarding their asymmetry and internal organization. In a first study, we confirm that both tracts have more extensive projections within the cortex than previously thought and present new results regarding asymmetrical tract branches. In a second study we further investigate the UF including its subcomponents. We resolve a century old debate by clarifying its elusive boundary with the IFOF and reveal the distinctive anatomical features including asymmetry patterns of each subcomponent. These results shed new light on the IFOF and UF and will be crucial for disentangling their multifunctional roles
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Bradstreet, Lauren E. « The Examination of White Matter Microstructure, Autism Traits, and Social Cognitive Abilities in Neurotypical Adults ». 2014. http://scholarworks.gsu.edu/psych_theses/127.
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The purpose of this study was to examine the relationships among mentalizing abilities, self-reported autism traits, and two white matter tracts, uncinate fasciculus (UF) and inferior longitudinal fasciculus (ILF), in neurotypical adults. UF and ILF were hypothesized to connect brain regions implicated in a neuroanatomical model of mentalizing. Data were available for 24 neurotypical adults (mean age = 21.92 (4.72) years; 15 women). Tract-based spatial statistics (TBSS) was used to conduct voxelwise cross-participant comparisons of fractional anisotropy (FA) values in UF and ILF as predicted by mentalizing abilities and self-reported autism traits. Self-reported autism traits were positively related to FA values in left ILF. Results suggest that microstructural differences in left ILF are specifically involved in the expression of subclinical autism traits in neurotypical individuals.
Chapitres de livres sur le sujet "Uncinate fasciculu"
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Schmahmann, Jeremy D., et Deepak N. Pandya. « Uncinate Fasciculus ». Dans Fiber Pathways of the Brain, 419–26. Oxford University Press, 2006. http://dx.doi.org/10.1093/acprof:oso/9780195104233.003.0016.
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Sato, Tetsuo, et Kotaro Minato. « Differences in Analysis Methods of the Human Uncinate Fasciculus Using Diffusion Tensor MRI ». Dans Advances in Bioinformatics and Biomedical Engineering, 162–70. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2113-8.ch017.
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The human uncinate fasciculus is an important cortico-cortical white matter pathway that directly connects the frontal and temporal lobes, but its exact functional role is not yet known. Using diffusion tensor Magnetic Resonance Imaging (MRI), the uncinate fasciculus can be extracted and its volume calculated. DTI metrics such as fractional anisotropy for the uncinate fasciculus can also be analyzed, but there are currently three different methods for this analysis. DTI reports on the uncinate fasciculus are conducted using region of interest, voxel-based, and fiber tracking deterministic approaches. Due to these differences in analysis methods, prior studies report conflicting levels of uncinate asymmetry measured with diffusion anisotropy. Here, the authors briefly introduce these three different methods for measuring uncinate asymmetry values and compare the results. This result can lead to a better understanding of the role of the uncinate fasciculus in future behavioral and clinical studies.
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Wong, Agnes. « Ocular Motor Disorders Caused by Lesions in the Cerebellum ». Dans Eye Movement Disorders. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195324266.003.0018.
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The vestibulocerebellum consists of the flocculus, ventral paraflocculus, nodulus, and uvula. ■ The flocculus receives inputs from the vestibular nucleus and nerve, nucleus prepositus hypoglossi (NPH), inferior olivary nucleus, cell groups of the paramedian tracts (PMT), nucleus reticularis tegmenti pontis (NRTP), and mesencephalic reticular formation. ■ The ventral paraflocculus receives inputs from contralateral pontine nuclei. ■ Project to ipsilateral superior and medial vestibular nuclei, and the y-group ■ Receive input from the medial and inferior vestibular nuclei, vestibular nerve, NPH, and inferior olivary nucleus ■ Project to the vestibular nuclei ■ The oculomotor vermis consists of parts of the declive, folium, tuber, and pyramis. ■ Receives inputs from the inferior olivary nucleus, vestibular nuclei, NPH, paramedian pontine reticular formation (PPRF), NRTP, and dorsolateral and dorsomedial pontine nuclei ■ Projects to the caudal fastigial nucleus ■ Stimulation of the Purkinje cells in the dorsal vermis elicits contralaterally directed saccades and smooth pursuit ■ Receives inputs from the dorsal vermis, inferior olivary nucleus, and NRTP ■ Decussates and projects via the uncinate fasciculus of the brachium conjunctivum to the contralateral PPRF, rostral interstitial nucleus of the medial longitudinal fasciculus, nucleus of the posterior commissure, omnipause neurons in nucleus raphe interpositus, the mesencephalic reticular formation, and superior colliculus ■ Neurons in the fastigial oculomotor region (FOR) fire during both ipsilateral and contralateral saccades. 1. The contralateral FOR neurons burst before the onset of saccade, and the onset of firing is not correlated with any property of the saccade. 2. Conversely, the time of onset for neurons in the ipsilateral FOR varies, with bursts occurring later for larger saccades. 3. Thus, the difference in time of onset between contralateral and ipsilateral FOR activity encodes the amplitude of saccades (i.e., the larger the difference in time of onset, the larger the saccade amplitude). Eye movement abnormalities in uncinate fasciculus lesion include hypometric ipsilesional saccades and hypermetric contralesional saccades (“contrapulsion”). Arnold-Chiari malformation is a malformation of the medullary–spinal junction with herniation of intracranial contents through the foramen magnum. The three types are illustrated in the figure below.
Actes de conférences sur le sujet "Uncinate fasciculu"
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Sato, T., N. Maruyama, T. Hoshida et K. Minato. « Correlation between uncinate fasciculus and memory tasks in healthy individual using diffusion tensor tractography ». Dans 2012 34th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2012. http://dx.doi.org/10.1109/embc.2012.6345958.
Texte intégral
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Baltazar, Gabriel Ferri, Leticia Franceschet Ribeiro, Mateus Henrique Nogueira, Ricardo Brioschi, Lucas Scárdua Silva, Rafael Batista João, Marina Alvim, Fernando Cendes et Clarissa Lin Yasuda. « Correlation between depressive and anxious symptoms and white matter changes in relatives of people with epilepsy ». Dans XIII Congresso Paulista de Neurologia. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1516-3180.616.
Texte intégralRésumé :
Background: depression and anxiety are common symptoms observed in people with epilepsy and their relatives. Objective: Investigate associations between white matter (WM) changes and psychiatric symptoms in relatives of TLE patients. Methods: We analyzed brain MRI with DTI from 40 TLE relatives and applied the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI). We extracted 6 WM tracts (fornix, cingulum, uncinate fasciculus (UF), inferior fronto-occipital fasciculus, corpus callosum, corticospinal tract) and analyzed fractional anisotropy (FA), medium diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). We investigated correlations between scores and the DTI measures. Symptoms of depression were positive with BDI scores above 10, while symptoms of anxiety were positive with BAI scores above 11. Results: we observed a prevalence of 37.5% of depressive symptoms and 27.5% of anxious symptoms. BDI correlated with FA in the left cingulum (p=0.0003;r=-0.547); and with MD in the right cingulum (p=0.015;r=0.401) and right and left UF (p=0.023;r=0.374 and p=0.021;r=0.363). BDI correlated also with RD in the left and right cingulum (p=0.0003;r=0.583 and p=0.015;r=0.401). BAI correlated with fornix`s FA (p=0.026;r=- 0.352), and with MD in the left cingulum (p=0.01;r=0.415) and left UF (p=0.003;r=0.374) and with RD in the left cingulum (p=0.022;r=0.371) and left UF (p=0.01;r=0.440). Discussion: The regions correlated with psychiatric symptoms here overlap with those affected in patients with epilepsy, however, they differ from areas mainly affected in patients with isolated depression. We hypothesize a possible genetic substrate involved in comorbidity between epilepsy and depression, distinct from psychiatric disease in people without epilepsy.