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fMRI stroke

Andrew J Lawrence, Daniel J Tozer, Emmanuel A Stamatakis, Hugh S Markus
Objective: MRI measures of network integrity may be useful disease markers in cerebral small vessel disease (SVD). We compared the sensitivity and reproducibility of MRI derived structural and functional network measures in healthy controls and SVD subjects. Methods: Diffusion tractography and resting state fMRI were used to create connectivity matrices from 26 subjects with symptomatic MRI confirmed lacunar stroke and 19 controls. Matrices were constructed at multiple scales based on a multi-resolution cortical atlas and at multiple thresholds for the matrix density...
2018: NeuroImage: Clinical
Grigori Yourganov, Julius Fridriksson, Brielle Stark, Christopher Rorden
We examined the effect of lesion on the resting-state functional connectivity in chronic post-stroke patients. We found many instances of strong correlations in BOLD signal measured at different locations within the lesion, making it hard to distinguish from the connectivity between intact and strongly connected regions. Regression of the mean cerebro-spinal fluid signal did not alleviate this problem. The connectomes computed by exclusion of lesioned voxels were not good predictors of the behavioral measures...
2018: NeuroImage: Clinical
M V Ivanova, O V Dragoy, S V Kuptsova, S Akinina Yu, A G Petrushevskii, O N Fedina, A Turken, V M Shklovsky, N F Dronkers
Currently, a distributed bilateral network of frontal-parietal areas is regarded as the neural substrate of working memory (WM), with the verbal WM network being more left-lateralized. This conclusion is based primarily on functional magnetic resonance imaging (fMRI) data that provides correlational evidence for brain regions involved in a task. However, fMRI cannot differentiate the areas that are fundamentally required for performing a task. These data can only come from brain-injured individuals who fail the task after the loss of specific brain areas...
March 8, 2018: Neuropsychologia
Jing Chen, Mingli Liu, Dalong Sun, Yan Jin, Tianrao Wang, Chuancheng Ren
BACKGROUND: Stroke is one of leading diseases causing adult death and disability worldwide. Home-based telerehabilitation has become a novel approach for stroke patients as effective as conventional rehabilitation, and more convenient and economical than conventional rehabilitation. However, there is no study assessing the mechanism of home-based telerehabilitation in promoting motor recovery among stroke patients with hemiplegic. AIMS: This study is designed to determine the efficacy and explore the mechanism of motor recovery after home-based telerehabilitation in stroke patients with motor deficits...
January 2018: Medicine (Baltimore)
Morgana Novaes, Fernanda Palhano-Fontes, Andre Peres, Kelley Mazzetto-Betti, Maristela Pelicioni, Kátia Andrade, Antonio Santos, Octavio Pontes-Neto, Draulio Araujo
BACKGROUND: Mirror therapy (MT) is becoming an alternative rehabilitation strategy for various conditions, including stroke. Although recent studies suggest the positive benefit of MT in chronic stroke motor recovery, little is known about its neural mechanisms. PURPOSE: To identify functional brain changes induced by a single MT intervention in ischemic stroke survivors, assessed by both Transcranial Magnetic Stimulation (TMS) and functional Magnetic Resonance Imaging (fMRI)...
March 1, 2018: International Journal of Neuroscience
Joshua S Siegel, Benjamin A Seitzman, Lenny E Ramsey, Mario Ortega, Evan M Gordon, Nico U F Dosenbach, Steven E Petersen, Gordon L Shulman, Maurizio Corbetta
Studies of stroke have identified local reorganization in perilesional tissue. However, because the brain is highly networked, strokes also broadly alter the brain's global network organization. Here, we assess brain network structure longitudinally in adult stroke patients using resting state fMRI. The topology and boundaries of cortical regions remain grossly unchanged across recovery. In contrast, the modularity of brain systems i.e. the degree of integration within and segregation between networks, was significantly reduced sub-acutely (n = 107), but partially recovered by 3 months (n = 85), and 1 year (n = 67)...
January 5, 2018: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
P H R Silva, C T Spedo, A A Barreira, R F Leoni
BACKGROUND: The Symbol Digit Modalities Test (SDMT) is widely used for cognitive evaluation of information processing speed (IPS), required in many cognitive operations. Despite being unspecific for different neurological disorders, it is sensitive to assess impaired performance related to stroke, Parkinson's disease, traumatic brain injury, and multiple sclerosis. However, in addition to evaluate the presence and severity of IPS impairment, it is of interest to determine the localization and integration of brain regions responsible for the functions assessed by the SDMT...
January 25, 2018: Multiple Sclerosis and related Disorders
Peiyao Zhang, Jing Wang, Qin Xu, Zheng Song, Jianping Dai, Jun Wang
OBJECTIVE: In previous studies, post-stroke depression (PSD) was found to be related to stroke characteristics as well as social and psychological factors. This study identified altered functional connectivity (FC) in patients with PSD at the subacute phase in three brain networks: default mood network (DMN), cognitive control network (CCN), and affective network (AN). The correlation between FC and the severity of PSD was investigated. MATERIALS AND METHODS: Resting-state functional magnetic resonance image (rs-fMRI) was performed on 26 PSD patients (6 females), 24 stroke patients without depression (5 females), and 24 age-matched normal controls (6 females) all aged 40-75 years...
January 4, 2018: European Journal of Radiology
Stefano Castruccio, Hernando Ombao, Marc G Genton
Functional Magnetic Resonance Imaging (fMRI) is a primary modality for studying brain activity. Modeling spatial dependence of imaging data at different spatial scales is one of the main challenges of contemporary neuroimaging, and it could allow for accurate testing for significance in neural activity. The high dimensionality of this type of data (on the order of hundreds of thousands of voxels) poses serious modeling challenges and considerable computational constraints. For the sake of feasibility, standard models typically reduce dimensionality by modeling covariance among regions of interest (ROIs)-coarser or larger spatial units-rather than among voxels...
January 22, 2018: Biometrics
Pedro Ramos-Cabrer, Daniel Padro
Stroke consists of the loss of cerebral functions resulting from the interruption of blood supply to a region of the brain, and represents the second cause of death and the leading cause of major disability in adults in Europe. Stroke is a very active field of research at preclinical and clinical levels, and Magnetic Resonance Imaging (MRI) is one of the most powerful tools that scientist and clinicians have for the study of the onset, evolution and consequences of this devastating disease, as well as for the monitoring of the success of available treatments, or for the development of novel therapeutic strategies...
2018: Methods in Molecular Biology
Priya Santhanam, E Susan Duncan, Steven L Small
Cortical reorganization after stroke is thought to underlie functional improvement. Patterns of reorganization may differ depending on the amount of time since the stroke or the degree of improvement. We investigated these issues in a study of brain connectivity changes with aphasia therapy. Twelve individuals with chronic aphasia participated in a 6-week trial of imitation-based speech therapy. We assessed improvement on a repetition test and analyzed effective connectivity during functional magnetic resonance imaging (fMRI) of a speech observation task before and after therapy...
January 16, 2018: Brain Connectivity
Anetta Lasek-Bal, Joanna Kidoń, Monika Błaszczyszyn, Bartłomiej Stasiów, Amadeusz Żak
Functional magnetic resonance imaging (fMRI) allows for the assessment of neuronal activity through the blood-level-dependent signal. The purpose of study was to evaluate the pattern of brain activity in fMRI in patients with ischemic stroke and to assess the potential relationship between the activity pattern and the neurological/functional status. METHODS: The fMRI was performed in patients up to 4th day of stroke. All the patients were analyzed according to NIHSS on 1st day and mRankin scale on 14th day of stroke, followed by analyzing of fMRI signal...
December 24, 2017: Neurologia i Neurochirurgia Polska
Glyn P Hallam, Hannah E Thompson, Mark Hymers, Rebecca E Millman, Jennifer M Rodd, Matthew A Lambon Ralph, Jonathan Smallwood, Elizabeth Jefferies
Damage to left inferior prefrontal cortex in stroke aphasia is associated with semantic deficits reflecting poor control over conceptual retrieval, as opposed to loss of knowledge. However, little is known about how functional recruitment within the semantic network changes in patients with executive-semantic deficits. The current study acquired functional magnetic resonance imaging (fMRI) data from 14 patients with semantic aphasia, who had difficulty with flexible semantic retrieval following left prefrontal damage, and 16 healthy age-matched controls, allowing us to examine activation and connectivity in the semantic network...
February 2018: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Sara B Pillay, William L Gross, William W Graves, Colin Humphries, Diane S Book, Jeffrey R Binder
Understanding the neural basis of recovery from stroke is a major research goal. Many functional neuroimaging studies have identified changes in brain activity in people with aphasia, but it is unclear whether these changes truly support successful performance or merely reflect increased task difficulty. We addressed this problem by examining differences in brain activity associated with correct and incorrect responses on an overt reading task. On the basis of previous proposals that semantic retrieval can assist pronunciation of written words, we hypothesized that recruitment of semantic areas would be greater on successful trials...
April 2018: Journal of Cognitive Neuroscience
Vladislav Balaev, Ivan Orlov, Alexey Petrushevsky, Olga Martynova
BACKGROUND: Previous studies have demonstrated altered resting state functional connectivity (rsFC) in patients with post-stroke depression (PSD). It remains unclear whether rsFC is changed at the network level as was shown for major depressive disorder (MDD). To address this question, we investigated rsFC of resting sate networks (RSNs) in PSD. METHODS: Eleven subjects with PSD underwent fMRI scanning at rest before and after treatment. The severity of depression was assessed using the aphasic depression rating scale (ADRS)...
November 13, 2017: Journal of Affective Disorders
Célise Haldin, Audrey Acher, Louise Kauffmann, Thomas Hueber, Emilie Cousin, Pierre Badin, Pascal Perrier, Diandra Fabre, Dominic Perennou, Olivier Detante, Assia Jaillard, Hélène Lœvenbruck, Monica Baciu
The rehabilitation of speech disorders benefits from providing visual information which may improve speech motor plans in patients. We tested the proof of concept of a rehabilitation method (Sensori-Motor Fusion, SMF; Ultraspeech player) in one post-stroke patient presenting chronic non-fluent aphasia. SMF allows visualisation by the patient of target tongue and lips movements using high-speed ultrasound and video imaging. This can improve the patient's awareness of his/her own lingual and labial movements, which can, in turn, improve the representation of articulatory movements and increase the ability to coordinate and combine articulatory gestures...
November 17, 2017: Clinical Linguistics & Phonetics
Yu Shi, Yanyan Zeng, Lei Wu, Ziping Liu, Shanshan Zhang, Jianming Yang, Wen Wu
Research on the mechanism of post stroke depression (PSD) is the key way to improve the treatment of PSD. However, the functional brain network of PSD has not been entirely supported by the results of functional magnetic resonance imaging (fMRI) studies. The aims of this study are to investigate the brain response of PSD in three different lesions. The brain responses of the three PSD subgroups were similar. However, each subgroup had its own characteristics of the brain network. In the temporal lobe subgroup, the right thalamus had increased degree centrality (DC) values which were different from the other two subgroups...
November 1, 2017: Scientific Reports
Patrick W Wright, Lindsey M Brier, Adam Q Bauer, Grant A Baxter, Andrew W Kraft, Matthew D Reisman, Annie R Bice, Abraham Z Snyder, Jin-Moo Lee, Joseph P Culver
The interplay between hemodynamic-based markers of cortical activity (e.g. fMRI and optical intrinsic signal imaging), which are an indirect and relatively slow report of neural activity, and underlying synaptic electrical and metabolic activity through neurovascular coupling is a topic of ongoing research and debate. As application of resting state functional connectivity measures is extended further into topics such as brain development, aging and disease, the importance of understanding the fundamental physiological basis for functional connectivity will grow...
2017: PloS One
Yu Shi, Yanyan Zeng, Lei Wu, Wei Liu, Ziping Liu, Shanshan Zhang, Jianming Yang, Wen Wu
Post stroke depression (PSD) is a serious complication of stroke. Brain imaging is an important method of studying the mechanism of PSD. However, few studies have focused on the single lesion location. The aim of this study was to investigate the brain mechanism of frontal lobe PSD using combined voxel-based morphometry (VBM) and functional magnetic resonance imaging (fMRI). In total, 30 first-time ischemic frontal lobe stroke patients underwent T1 weighted MRI and resting-state fMRI scans. Clinical assessments included the 24-item Hamilton Rating Scale for Depression, the National Institutes of Health Stroke Scale, and the Mini-Mental State Examination...
October 16, 2017: Scientific Reports
Tianlu Wang, Dante Mantini, Celine R Gillebert
Real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback aids the modulation of neural functions by training self-regulation of brain activity through operant conditioning. This technique has been applied to treat several neurodevelopmental and neuropsychiatric disorders, but its effectiveness for stroke rehabilitation has not been examined yet. Here, we systematically review the effectiveness of rt-fMRI neurofeedback training in modulating motor and cognitive processes that are often impaired after stroke...
September 18, 2017: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
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