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Helena Verhelst, Catharine Vander Linden, Toon De Pauw, Guy Vingerhoets, Karen Caeyenberghs
Recent evidence has shown the presence of a "rich club" in the brain, which constitutes a core network of highly interconnected and spatially distributed brain regions, important for high-order cognitive processes. This study aimed to map the rich club organization in 17 young patients with moderate to severe TBI (15.71 ± 1.75 years) in the chronic stage of recovery and 17 age- and gender-matched controls. Probabilistic tractography was performed on diffusion weighted imaging data to construct the edges of the structural connectomes using number of streamlines as edge weight...
March 12, 2018: Human Brain Mapping
Evangelia Tsolaki, Angela Downes, William Speier, W Jeff Elias, Nader Pouratian
Magnetic Resonance-guided Focused UltraSound (MRgFUS) offers an incisionless approach to treat essential tremor (ET). Due to lack of evident internal anatomy on traditional structural imaging, indirect targeting must still be used to localize the lesion. Here, we investigate the potential predictive value of probabilistic tractography guided thalamic targeting by defining how tractography-defined targets, lesion size and location, and clinical outcomes interrelate. MR imaging and clinical outcomes from 12 ET patients that underwent MRgFUS thalamotomy in a pilot study at the University of Virginia were evaluated in this analysis...
2018: NeuroImage: Clinical
Christopher S Parker, Jonathan D Clayden, M Jorge Cardoso, Roman Rodionov, John S Duncan, Catherine Scott, Beate Diehl, Sebastien Ourselin
Patients with medically-refractory focal epilepsy may be candidates for neurosurgery and some may require placement of intracranial EEG electrodes to localise seizure onset. Assessing cerebral responses to single pulse electrical stimulation (SPES) may give diagnostically useful data. SPES produces cortico-cortical evoked potentials (CCEPs), which infer effective brain connectivity. Diffusion-weighted images and tractography may be used to estimate structural brain connectivity. This combination provides the opportunity to observe seizure onset and its propagation throughout the brain, spreading contiguously along the cortex explored with electrodes, or non-contiguously...
2018: NeuroImage: Clinical
Patrick W Hales, Victoria Smith, Deepi Dhanoa-Hayre, Patricia O'Hare, Kshitij Mankad, Felice d'Arco, Jessica Cooper, Ramneek Kaur, Kim Phipps, Richard Bowman, Darren Hargrave, Christopher Clark
Background: Radiological biomarkers which correlate with visual function are needed to improve the clinical management of optic pathway glioma (OPG) patients. Currently, these are not available using conventional magnetic resonance imaging (MRI) sequences. The aim of this study was to determine whether diffusion MRI could be used to delineate the entire optic pathway in OPG patients, and provide imaging biomarkers within this pathway which correlate with a patient's visual acuity (VA)...
2018: NeuroImage: Clinical
Christina Andica, Koji Kamagata, Taku Hatano, Ayami Okuzumi, Asami Saito, Misaki Nakazawa, Ryo Ueda, Yumiko Motoi, Kouhei Kamiya, Michimasa Suzuki, Masaaki Hori, Kanako K Kumamaru, Nobutaka Hattori, Shigeki Aoki
INTRODUCTION: Parkinson's disease (PD) is marked by the degeneration of dopaminergic neurons in the nigrostriatal pathway (NSP). We aimed to identify the microstructural changes in the NSP of PD patients using neurite orientation dispersion and density imaging (NODDI). METHODS: NSPs of 29 PD patients, who were retrospectively selected from patients previously admitted to our institution, and 29 age- and gender-matched healthy controls were isolated via deterministic tractography...
February 28, 2018: Parkinsonism & related Disorders
Giuseppina Caiazzo, Michele Fratello, Federica Di Nardo, Francesca Trojsi, Gioacchino Tedeschi, Fabrizio Esposito
PURPOSE: Advances in computational network analysis have enabled the characterization of topological properties of human brain networks (connectomics) from high angular resolution diffusion imaging (HARDI) MRI structural measurements. In this study, the effect of changing the diffusion weighting (b value) and sampling (number of gradient directions) was investigated in ten healthy volunteers, with specific focus on graph theoretical network metrics used to characterize the human connectome...
March 8, 2018: Neuroradiology
Giovanni Battistella, Veena Kumar, Kristina Simonyan
The importance of insula in speech control is acknowledged but poorly understood, partly due to a variety of clinical symptoms resulting from insults to this structure. To clarify its structural organization within the speech network in healthy subjects, we used probabilistic diffusion tractography to examine insular connectivity with three cortical regions responsible for sound processing [Brodmann area (BA) 22], motor preparation (BA 44) and motor execution (laryngeal/orofacial primary motor cortex, BA 4)...
March 8, 2018: Brain Structure & Function
Gaia Olivo, Francesco Latini, Lyle Wiemerslage, Elna-Marie Larsson, Helgi B Schiöth
Background : Neurovascular coupling is associated with white matter (WM) structural integrity, and it is regulated by specific subtypes of dopaminergic receptors. An altered activity of such receptors, highly expressed in reward-related regions, has been reported in carriers of obesity-risk alleles of the fat mass and obesity associated ( FTO ) gene. Among the reward-related regions, the thalamus and the nucleus accumbens are particularly vulnerable to blood pressure dysregulation due to their peculiar anatomo-vascular characteristics, and have been consistently reported to be altered in early-stage obesity...
2018: Frontiers in Human Neuroscience
J Hadida, S N Sotiropoulos, R G Abeysuriya, M W Woolrich, S Jbabdi
The relationship between structure and function in the human brain is well established, but not yet well characterised. Large-scale biophysical models allow us to investigate this relationship, by leveraging structural information (e.g.derived from diffusion tractography) in order to couple dynamical models of local neuronal activity into networks of interacting regions distributed across the cortex. In practice however, these models are difficult to parametrise, and their simulation is often delicate and computationally expensive...
March 5, 2018: NeuroImage
Ke Tang, Yaqun Zhao, Xiaodong Yuan
No abstract text is available yet for this article.
March 6, 2018: Neurosurgery
Sung Ho Jang, Younghyeon Kwon
RATIONALE: A 45-year-old right-handed female patient suffered head trauma after being hit by a truck that ran into a house. PATIENT CONCERNS: The patient lost consciousness for 1 hour and experienced posttraumatic amnesia for 1 month after the accident. DIAGNOSES: She underwent conservative management for a subdural hematoma in the left frontotemporal lobes and intracerebral hematoma in the left frontal lobe. INTERVENTIONS: The patient's Glasgow Coma Scale score was 11...
March 2018: Medicine (Baltimore)
Fuyu Wang, Jiashu Zhang, Peng Wang, Tao Zhou, Xianghui Meng, Jinli Jiang
The preservation of pituitary stalk during surgery is very important for neurosurgeons. Sometimes, it is hard to identify the pituitary stalk in the operation. The hypothalamo-hypophyseal tract (HHT) projects through the pituitary stalk to the posterior pituitary gland. If the HHT can be identified, the position of pituitary stalk will be visualized. The diffusion tensor imaging (DTI) fiber tracking technique has been widely used for the quantitative assessment of the white matter integrity and thus may be suitable for the evaluation of the HHT...
March 2018: Medicine (Baltimore)
Hao Yan, Owen Carmichael, Debashis Paul, Jie Peng
We present a novel method for estimation of the fiber orientation distribution (FOD) function based on diffusion-weighted magnetic resonance imaging (D-MRI) data. We formulate the problem of FOD estimation as a regression problem through spherical deconvolution and a sparse representation of the FOD by a spherical needlets basis that forms a multi-resolution tight frame for spherical functions. This sparse representation allows us to estimate the FOD by ℓ1 -penalized regression under a non-negativity constraint on the estimated FOD...
February 8, 2018: Medical Image Analysis
Raluca Pascalau, Roxana Popa Stănilă, Silviu Sfrângeu, Bianca Szabo
BACKGROUND: The limbic tracts are involved in crucial cerebral functions such as memory, emotion and behavior. The complex architecture of the limbic circuit makes it harder to approach compared to other white matter networks. Our study aims to describe the three-dimensional anatomy of the limbic white matter by use of two complementary study methods, namely ex vivo fiber dissection and in vivo MRI based tractography. METHODS: Three fiber dissection protocols were performed using blunt wooden instruments and a surgical microscope on formalin fixed brains prepared according to the Klingler method...
February 28, 2018: World Neurosurgery
Olga Tymofiyeva, Eva Henje Blom, Tiffany C Ho, Colm G Connolly, Daniel Lindqvist, Owen M Wolkowitz, Jue Lin, Kaja Z LeWinn, Matthew D Sacchet, Laura K M Han, Justin P Yuan, Sarina P Bhandari, Duan Xu, Tony T Yang
BACKGROUND: Adolescent anxiety and depression are highly prevalent psychiatric disorders that are associated with altered molecular and neurocircuit profiles. Recently, increased mitochondrial DNA copy number (mtDNA-cn) has been found to be associated with several psychopathologies in adults, especially anxiety and depression. The associations between mtDNA-cn and anxiety and depression have not, however, been investigated in adolescents. Moreover, to date there have been no studies examining associations between mtDNA-cn and brain network alterations in mood disorders in any age group...
February 17, 2018: Journal of Affective Disorders
Kathleen J Maheras, Marcello Peppi, Farhad Ghoddoussi, Matthew P Galloway, Shane A Perrine, Alexander Gow
Neuronal origins of behavioral disorders have been examined for decades to construct frameworks for understanding psychiatric diseases and developing useful therapeutic strategies with clinical application. Despite abundant anecdotal evidence for white matter etiologies, including altered tractography in neuroimaging and diminished oligodendrocyte-specific gene expression in autopsy studies, mechanistic data demonstrating that dysfunctional myelin sheaths can cause behavioral deficits and perturb neurotransmitter biochemistry have not been forthcoming...
February 28, 2018: Scientific Reports
Giorgio M Innocenti, Roberto Caminiti, Eric M Rouiller, Graham Knott, Tim B Dyrby, Maxime Descoteaux, Jean-Philippe Thiran
The axonal composition of cortical projections originating in premotor, supplementary motor (SMA), primary motor (a4), somatosensory and parietal areas and descending towards the brain stem and spinal cord was characterized in the monkey with histological tract tracing, electron microscopy (EM) and diffusion MRI (dMRI). These 3 approaches provided complementary information. Histology provided accurate assessment of axonal diameters and size of synaptic boutons. dMRI revealed the topography of the projections (tractography), notably in the internal capsule...
February 27, 2018: Cerebral Cortex
Graham L Baum, David R Roalf, Philip A Cook, Rastko Ciric, Adon F G Rosen, Cedric Xia, Mark A Elliott, Kosha Ruparel, Ragini Verma, Birkan Tunc, Ruben C Gur, Raquel E Gur, Danielle S Bassett, Theodore D Satterthwaite
Multiple studies have shown that data quality is a critical confound in the construction of brain networks derived from functional MRI. This problem is particularly relevant for studies of human brain development where important variables (such as participant age) are correlated with data quality. Nevertheless, the impact of head motion on estimates of structural connectivity derived from diffusion tractography methods remains poorly characterized. Here, we evaluated the impact of in-scanner head motion on structural connectivity using a sample of 949 participants (ages 8-23 years old) who passed a rigorous quality assessment protocol for diffusion magnetic resonance imaging (dMRI) acquired as part of the Philadelphia Neurodevelopmental Cohort...
February 24, 2018: NeuroImage
Thomas Schultz, Anna Vilanova
Modern diffusion magnetic resonance imaging (dMRI) acquires intricate volume datasets and biological meaning can only be found in the relationship between its different measurements. Suitable strategies for visualizing these complicated data have been key to interpretation by physicians and neuroscientists, for drawing conclusions on brain connectivity and for quality control. This article provides an overview of visualization solutions that have been proposed to date, ranging from basic grayscale and color encodings to glyph representations and renderings of fiber tractography...
February 27, 2018: NMR in Biomedicine
Danuta M Lisiecka-Ford, Daniel J Tozer, Robin G Morris, Andrew J Lawrence, Thomas R Barrick, Hugh S Markus
INTRODUCTION: Apathy is a common yet under-recognised feature of cerebral small vessel disease (SVD), but its underlying neurobiological basis is not yet understood. We hypothesized that damage to the reward network is associated with an increase of apathy in patients with SVD. METHODS: In 114 participants with symptomatic SVD, defined as a magnetic resonance imaging confirmed lacunar stroke and confluent white matter hyperintensities, we used diffusion tensor imaging tractography to derive structural brain networks and graph theory to determine network efficiency...
February 15, 2018: Journal of Affective Disorders
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