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https://www.readbyqxmd.com/read/28107807/continuous-theta-burst-stimulation-may-improve-visuospatial-neglect-via-modulating-the-attention-network-a-randomized-controlled-study
#1
Wei Fu, Lei Cao, Yanming Zhang, Su Huo, JuBao Du, Lin Zhu, Weiqun Song
BACKGROUND: Visuospatial neglect (VSN) is devastating and common after stroke, and is thought to involve functional disturbance of the attention network. Non-invasive theta-burst stimulation (TBS) may help restore the normal function of attention network, therefore facilitating recovery from VSN. OBJECTIVE: This study investigated the effects of continuous TBS on resting-state functional connectivity (RSFC) in the attention network, and behavioral performances of patients with VSN after stroke...
January 20, 2017: Topics in Stroke Rehabilitation
https://www.readbyqxmd.com/read/28039678/studying-the-neural-bases-of-prism-adaptation-using-fmri-a-technical-and-design-challenge
#2
Janet H Bultitude, Alessandro Farnè, Romeo Salemme, Danielle Ibarrola, Christian Urquizar, Jacinta O'Shea, Jacques Luauté
Prism adaptation induces rapid recalibration of visuomotor coordination. The neural mechanisms of prism adaptation have come under scrutiny since the observations that the technique can alleviate hemispatial neglect following stroke, and can alter spatial cognition in healthy controls. Relative to non-imaging behavioral studies, fMRI investigations of prism adaptation face several challenges arising from the confined physical environment of the scanner and the supine position of the participants. Any researcher who wishes to administer prism adaptation in an fMRI environment must adjust their procedures enough to enable the experiment to be performed, but not so much that the behavioral task departs too much from true prism adaptation...
December 30, 2016: Behavior Research Methods
https://www.readbyqxmd.com/read/28004991/bilateral-versus-ipsilesional-cortico-subcortical-activity-patterns-in-stroke-show-hemispheric-dependence
#3
A Cristina Vidal, Paula Banca, Augusto G Pascoal, Gustavo C Santo, João Sargento-Freitas, Ana Gouveia, Miguel Castelo-Branco
Background Understanding of interhemispheric interactions in stroke patients during motor control is an important clinical neuroscience quest that may provide important clues for neurorehabilitation. In stroke patients, bilateral overactivation in both hemispheres has been interpreted as a poor prognostic indicator of functional recovery. In contrast, ipsilesional patterns have been linked with better motor outcomes. Aim We investigated the pathophysiology of hemispheric interactions during limb movement without and with contralateral restraint, to mimic the effects of constraint-induced movement therapy...
January 2017: International Journal of Stroke: Official Journal of the International Stroke Society
https://www.readbyqxmd.com/read/27995067/brain-imaging-correlates-of-recovered-swallowing-after-dysphagic-stroke-a-fmri-and-dwi-study
#4
Paul Glad Mihai, Mareile Otto, Martin Domin, Thomas Platz, Shaheen Hamdy, Martin Lotze
Neurogenic dysphagia frequently occurs after stroke and deglutitive aspiration is one of the main reasons for subacute death after stroke. Although promising therapeutic interventions for neurogenic dysphagia are being developed, the functional neuroanatomy of recovered swallowing in this population remains uncertain. Here, we investigated 18 patients post-stroke who recovered from dysphagia using an event related functional magnetic resonance imaging (fMRI) study of swallowing. Patients were characterized by initial dysphagia score (mild to severe), lesion mapping, white matter fractional anisotropy (FA) of the pyramidal tracts, and swallowing performance measurement during fMRI scanning...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27965899/the-role-of-the-cognitive-control-system-in-recovery-from-bilingual-aphasia-a-multiple-single-case-fmri-study
#5
Narges Radman, Michael Mouthon, Marie Di Pietro, Chrisovalandou Gaytanidis, Beatrice Leemann, Jubin Abutalebi, Jean-Marie Annoni
Aphasia in bilingual patients is a therapeutic challenge since both languages can be impacted by the same lesion. Language control has been suggested to play an important role in the recovery of first (L1) and second (L2) language in bilingual aphasia following stroke. To test this hypothesis, we collected behavioral measures of language production (general aphasia evaluation and picture naming) in each language and language control (linguistic and nonlinguistic switching tasks), as well as fMRI during a naming task at one and four months following stroke in five bilingual patients suffering from poststroke aphasia...
2016: Neural Plasticity
https://www.readbyqxmd.com/read/27956263/functional-modulation-of-contralateral-bias-in-early-and-object-selective-areas-after-stroke-of-the-occipital-ventral-cortices
#6
Maren Praß, Cathleen Grimsen, Manfred Fahle
Object agnosia is a rare symptom, occurring mainly after bilateral damage of the ventral visual cortex. Most patients suffering from unilateral ventral lesions are clinically non-agnosic. Here, we studied the effect of unilateral occipito-temporal lesions on object categorization and its underlying neural correlates in visual areas. Thirteen non-agnosic stroke patients and twelve control subjects performed an event-related rapid object categorization task in the fMRI scanner where images were presented either to the left or to the right of a fixed point...
December 9, 2016: Neuropsychologia
https://www.readbyqxmd.com/read/27920978/network-interactions-underlying-mirror-feedback-in-stroke-a-dynamic-causal-modeling-study
#7
Soha Saleh, Mathew Yarossi, Thushini Manuweera, Sergei Adamovich, Eugene Tunik
Mirror visual feedback (MVF) is potentially a powerful tool to facilitate recovery of disordered movement and stimulate activation of under-active brain areas due to stroke. The neural mechanisms underlying MVF have therefore been a focus of recent inquiry. Although it is known that sensorimotor areas can be activated via mirror feedback, the network interactions driving this effect remain unknown. The aim of the current study was to fill this gap by using dynamic causal modeling to test the interactions between regions in the frontal and parietal lobes that may be important for modulating the activation of the ipsilesional motor cortex during mirror visual feedback of unaffected hand movement in stroke patients...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27890008/functional-connectivity-analysis-of-brain-default-mode-networks-using-hamiltonian-path
#8
Zhuqing Jiao, Kai Ma, Huan Wang, Ling Zou, Jianbo Xiang
The aim of this study is to introduce Hamiltonian path to analyze functional connectivity of brain default mode networks (DMNs). Firstly, the brain DMNs in resting state are constructed with the employment of functional Magnetic Resonance Imaging (fMRI) data. Then, the Dijkstra algorithm is used to calculate the shortest path length of the node which represents each brain region, and the Hamiltonian path of the default network is solved through the improved adaptive ant colony algorithm. Finally, complex network analysis methods are introduced to discuss the node and network properties of brain functional connectivity in both normal subjects and stroke patients...
November 24, 2016: CNS & Neurological Disorders Drug Targets
https://www.readbyqxmd.com/read/27859982/transcranial-direct-current-stimulation-effects-on-neural-processing-in-post-stroke-aphasia
#9
Robert Darkow, Andrew Martin, Anna Würtz, Agnes Flöel, Marcus Meinzer
Non-invasive transcranial direct current stimulation (tDCS) can enhance recovery after stroke. However, fundamental knowledge about how tDCS impacts neural processing in the lesioned human brain is currently lacking. In the present study, it was investigated how tDCS modulates brain function in patients with post-stroke language impairment (aphasia). In a cross-over, randomized trial, patients named pictures of common objects during functional magnetic resonance imaging (fMRI). Concurrently, excitatory (anodal-) or sham-tDCS (1 mA, 20 min, or 30 s, respectively) was administered to the left primary motor cortex, a montage with demonstrated potential to improve aphasic language...
November 11, 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/27859975/population-level-correction-of-systematic-motion-artifacts-in-fmri-in-patients-with-ischemic-stroke
#10
Csaba Aranyi, Gábor Opposits, Marianna Nagy, Ervin Berényi, Csilla Vér, László Csiba, Péter Katona, Tamás Spisák, Miklós Emri
BACKGROUND: The aim of this study was to reveal potential sources of systematic motion artifacts in stroke functional magnetic resonance imaging (fMRI) focusing on those causing stimulus-correlated motion on the individual-level and separate the motion effect on the fMRI signal changing from the activation-induced alteration at population level. METHODS: Eleven ischemic stroke patients were examined by fMRI. The fMRI paradigm was based on passive ankle movement on both the healthy and the paretic leg's side...
November 17, 2016: Journal of Neuroimaging: Official Journal of the American Society of Neuroimaging
https://www.readbyqxmd.com/read/27859933/spectroscopic-biomarkers-of-motor-cortex-developmental-plasticity-in-hemiparetic-children-after-perinatal-stroke
#11
Helen L Carlson, Frank P MacMaster, Ashley D Harris, Adam Kirton
Perinatal stroke causes hemiparetic cerebral palsy and lifelong motor disability. Bilateral motor cortices are key hubs within the motor network and their neurophysiology determines clinical function. Establishing biomarkers of motor cortex function is imperative for developing and evaluating restorative interventional strategies. Proton magnetic resonance spectroscopy (MRS) quantifies metabolite concentrations indicative of underlying neuronal health and metabolism in vivo. We used functional magnetic resonance imaging (MRI)-guided MRS to investigate motor cortex metabolism in children with perinatal stroke...
November 17, 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/27859903/corticostriatal-connectivity-fingerprints-probability-maps-based-on-resting-state-functional-connectivity
#12
Ellen Jaspers, Joshua H Balsters, Pegah Kassraian Fard, Dante Mantini, Nicole Wenderoth
Over the last decade, structure-function relationships have begun to encompass networks of brain areas rather than individual structures. For example, corticostriatal circuits have been associated with sensorimotor, limbic, and cognitive information processing, and damage to these circuits has been shown to produce unique behavioral outcomes in Autism, Parkinson's Disease, Schizophrenia and healthy ageing. However, it remains an open question how abnormal or absent connectivity can be detected at the individual level...
November 12, 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/27846290/altered-effective-connectivity-of-the-primary-motor-cortex-in-stroke-a-resting-state-fmri-study-with-granger-causality-analysis
#13
Zhiyong Zhao, Xiangmin Wang, Mingxia Fan, Dazhi Yin, Limin Sun, Jie Jia, Chaozheng Tang, Xiaohui Zheng, Yuwei Jiang, Jie Wu, Jiayu Gong
The primary motor cortex (M1) is often abnormally recruited in stroke patients with motor disabilities. However, little is known about the alterations in the causal connectivity of M1 following stroke. The purpose of the present study was to investigate whether the effective connectivity of the ipsilesional M1 is disturbed in stroke patients who show different outcomes in hand motor function. 23 patients with left-hemisphere subcortical stroke were selected and divided into two subgroups: partially paralyzed hands (PPH) and completely paralyzed hands (CPH)...
2016: PloS One
https://www.readbyqxmd.com/read/27826107/increased-functional-connectivity-one-week-after-motor-learning-and-tdcs-in-stroke-patients
#14
Stéphanie Lefebvre, Laurence Dricot, Patrice Laloux, Philippe Desfontaines, Frédéric Evrard, André Peeters, Jacques Jamart, Yves Vandermeeren
Recent studies using resting-state functional magnetic resonance imaging (rs-fMRI) demonstrated that changes in functional connectivity (FC) after stroke correlate with recovery. The aim of this study was to explore whether combining motor learning to dual transcranial direct current stimulation (dual-tDCS, applied over both primary motor cortices (M1)) modulated FC in stroke patients. Twenty-two chronic hemiparetic stroke patients participated in a baseline rs-fMRI session. One week later, dual-tDCS/sham was applied during motor skill learning (intervention session); one week later, the retention session started with the acquisition of a run of rs-fMRI imaging...
January 6, 2017: Neuroscience
https://www.readbyqxmd.com/read/27790102/the-calculation-of-language-lateralization-indices-in-post-stroke-aphasia-a-comparison-of-a-standard-and-a-lesion-adjusted-formula
#15
Aimee Dietz, Jennifer Vannest, Thomas Maloney, Mekibib Altaye, Jerzy P Szaflarski, Scott K Holland
Background: The language lateralization index (LI) is a valuable tool in functional magnetic resonance imaging (fMRI) research, especially in people with post-stroke aphasia. However, there is inconsistent consideration for the overlap of lesions with regions of interest (ROIs). The purpose of this study was to determine whether standard LI (SLI) and lesion-adjusted LI (LALI) formulae generate different LI values and language lateralization classification for people with post-stroke chronic aphasia. Methods: SLI and LALI were calculated for an event-related (overt) verb generation task in an anterior and a posterior language ROI...
2016: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/27676998/effect-of-visual-feedback-on-speech-recovery-and-language-plasticity-in-patients-with-post-stroke-non-fluent-aphasia-functional-mri-assessment
#16
Monica Baciu, Audrey Acher, Louise Kauffmann, Emilie Cousin, Claire Boilley, Thomas Hueber, Pierre Badin, Pascal Perrier, Diandra Fabre, Assia Jaillard, Olivier Detante, Dominique Perennou
OBJECTIVE: To assess the efficiency of Visual Feedback (VF) on language recovery and plasticity in three chronic non-fluent aphasic patients. VF is based on language-action interaction, thus, language skills are improved by rehabilitation strategies based on execution and observation of motor actions. VF is an ultrasound system coupled with video images, allowing patients to 'see their own lips and tongue at work' during speech and improve their awareness of their lingual and labial movements and their ability to coordinate and combine phonemes and syllables...
September 2016: Annals of Physical and Rehabilitation Medicine
https://www.readbyqxmd.com/read/27676986/cortical-activity-and-egocentric-representation-an-fmri-study
#17
Annelise Raillon Moulinet, Lucie Chochina, Stéphanie Challois Leplaideur, Elise Bannier, Jean-Christophe Ferre, Isabelle Bonan
OBJECTIVE: Subjects use different referentials for spatial localization, and the egocentric references are very often impaired especially during stroke. The objective is to find the difference between activations induced by 2 egocentric tasks MATERIAL/PATIENTS AND METHODS: Seventeen right-handed healthy subjects (50.4±14.9 years) were tested using fMRI during the realization of 2 egocentric spatial tasks: the perception of the straight ahead (retinocentric) and the longitudinal axis of the body (centered by the trunk)...
September 2016: Annals of Physical and Rehabilitation Medicine
https://www.readbyqxmd.com/read/27676978/modified-brain-activations-in-the-non-damaged-hemisphere-during-movements-of-the-supposed-to-be-healthy-upper-limb
#18
Liesjet Van Dokkum, Emmanuelle Le Bars, Denis Mottet, Alain Bonafe, Nicolas Menjot de Champfleur, Isabelle Laffont
OBJECTIVE: After stroke, the less affected upper-limb shows slight but substantial and longterm motor deficits [1]. Kinematically, this is reflected by an increased segmentation of movements. Here, we aim to define how these changes in behavior are accompanied by changes in brain activation. MATERIAL/PATIENTS AND METHODS: Twenty-one sub-acute post-stroke patients with a first-ever unilateral ischemic stroke of the middle cerebral artery participated in this study twice: within the first 6 weeks post-stroke and after 6 weeks of rehabilitation...
September 2016: Annals of Physical and Rehabilitation Medicine
https://www.readbyqxmd.com/read/27605617/glial-cell-calcium-signaling-mediates-capillary-regulation-of-blood-flow-in-the-retina
#19
Kyle R Biesecker, Anja I Srienc, Angela M Shimoda, Amit Agarwal, Dwight E Bergles, Paulo Kofuji, Eric A Newman
UNLABELLED: The brain is critically dependent on the regulation of blood flow to nourish active neurons. One widely held hypothesis of blood flow regulation holds that active neurons stimulate Ca(2+) increases in glial cells, triggering glial release of vasodilating agents. This hypothesis has been challenged, as arteriole dilation can occur in the absence of glial Ca(2+) signaling. We address this controversy by imaging glial Ca(2+) signaling and vessel dilation in the mouse retina. We find that sensory stimulation results in Ca(2+) increases in the glial endfeet contacting capillaries, but not arterioles, and that capillary dilations often follow spontaneous Ca(2+) signaling...
September 7, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27595065/decoding-post-stroke-motor-function-from-structural-brain-imaging
#20
Jane M Rondina, Maurizio Filippone, Mark Girolami, Nick S Ward
Clinical research based on neuroimaging data has benefited from machine learning methods, which have the ability to provide individualized predictions and to account for the interaction among units of information in the brain. Application of machine learning in structural imaging to investigate diseases that involve brain injury presents an additional challenge, especially in conditions like stroke, due to the high variability across patients regarding characteristics of the lesions. Extracting data from anatomical images in a way that translates brain damage information into features to be used as input to learning algorithms is still an open question...
2016: NeuroImage: Clinical
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