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Casey Rosen, Larissa McKetton, Jeremy Russell, Kevin Sam, Julien Poublanc, Adrian Crawley, Jay S Han, Olivia Sobczyk, James Duffin, Danny M Mandell, Michael Tymianski, Joseph A Fisher, David J Mikulis, Lashmi Venkatraghavan
The purpose of this retrospective observational study is to investigate the long-term changes in cerebrovascular reactivity (CVR) as a measure of cerebral hemodynamics in patients with intracranial steno-occlusive disease (IC-SOD) after they have undergone an Extracranial-intracranial (EC-IC) bypass. Twenty-six patients suffering from IC-SOD were selected from our CVR database. Nineteen patients underwent unilateral and 7 underwent bilateral revascularization. CVR measurements were done using BOLD-MRI and precisely controlled CO2 and expressed as ΔBOLD (%)/Δ PET CO2 (mmHg)...
June 12, 2018: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
Jacquie R Baker, Justin R Paturel, Kurt Kimpinski
PURPOSE: Neurogenic orthostatic hypotension (NOH), is a cardinal feature of autonomic dysfunction. The cortical autonomic network (CAN) is a network of brain regions associated with autonomic function. Therefore, our objective was to investigate whether impairment of CAN structures is involved in the pathophysiology of NOH. METHODS: Fifteen controls (63{plus minus}13 years) and fifteen NOH patients (67{plus minus}6 years; p=0.2) with peripheral autonomic dysfunction completed standard tests of parasympathetic [Deep Breathing (DB)] and sympathetic [Valsalva maneuver (VM)] activation during a functional MRI...
June 14, 2018: Journal of Applied Physiology
Alex T L Leong, Celia M Dong, Patrick P Gao, Russell W Chan, Anthea To, Dan H Sanes, Ed X Wu
Sensory cortices contain extensive descending (corticofugal) pathways, yet their impact on brainstem processing - particularly across sensory systems - remains poorly understood. In the auditory system, the inferior colliculus (IC) in the midbrain receives cross-modal inputs from the visual cortex (VC). However, the influences from VC on auditory midbrain processing are unclear. To investigate whether and how visual cortical inputs affect IC auditory responses, the present study combines auditory blood-oxygenation-level-dependent (BOLD) functional MRI (fMRI) with cell-type specific optogenetic manipulation of visual cortex...
June 7, 2018: Scientific Reports
Darian H Hadjiabadi, Leland Pung, Jiangyang Zhang, B D Ward, Woo-Taek Lim, Meghana Kalavar, Nitish V Thakor, Bharat B Biswal, Arvind P Pathak
Brain tumor patients often experience functional deficits that extend beyond the tumor site. While resting-state functional MRI (rsfMRI) has been used to map such functional connectivity changes in brain tumor patients, the interplay between abnormal tumor vasculature and the rsfMRI signal is still not well understood. Therefore, there is an exigent need for new tools to elucidate how the blood‑oxygenation-level-dependent (BOLD) rsfMRI signal is modulated in brain cancer. In this initial study, we explore the utility of a preclinical model for quantifying brain tumor-induced changes on the rsfMRI signal and resting-state brain connectivity...
2018: NeuroImage: Clinical
Sonu Kashyap, Mazen Osman, Christopher M Ferguson, Meryl C Nath, Bhaskar Roy, Karen R Lien, Karl A Nath, Vesna D Garovic, Lilach O Lerman, Joseph P Grande
Inflammation plays an important role in the pathogenesis of renal and cardiovascular disease in renovascular hypertension (RVH). Ccl2 is an important mediator of inflammation, and is induced within 24 hours following surgery to establish RVH in the murine 2 kidney 1 clip model, a time prior to onset of interstitial inflammation, fibrosis, or tubular atrophy. We tested the hypothesis that Ccl2 deficiency protects the stenotic kidney (STK) from development of chronic renal damage in mice with renovascular hypertension due to renal artery stenosis (RAS)...
June 5, 2018: Scientific Reports
Rajesh Pg, Thomas Bejoy, Chandrasekhar Pammi Vs, Kesavadas Chandrasekharan, Radhakrishnan Ashalatha, Alexander Aley, Thomas Sanjeev V, Menon Ramshekhar N
OBJECTIVES: To validate concurrent utility of within-scanner encoding and delayed recognition-memory paradigms to ascertain hippocampal activations during task-based memory fMRI. METHODS: Memory paradigms were designed for faces, word-pairs and abstract designs. A deep-encoding task was designed comprising of a total of 9 cycles run within a 1.5T MRI scanner. A recall session was performed after 1 h within the scanner using an event-related design. Group analysis was done with 'correct-incorrect' responses applied as parametric modulators in Statistical Parametric Mapping version 8 using boot-strap method to enable estimation of laterality indices (LI) using custom anatomical masks involving the medio-basal temporal structures...
May 26, 2018: Epilepsy Research
M Ethan MacDonald, Avery J L Berman, Erin L Mazerolle, Rebecca J Williams, G Bruce Pike
A new method is proposed for obtaining cerebral perfusion measurements whereby blood oxygen level dependent (BOLD) MRI is used to dynamically monitor hyperoxia-induced changes in the concentration of deoxygenated hemoglobin in the cerebral vasculature. The data is processed using kinetic modeling to yield perfusion metrics, namely: cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). Ten healthy human subjects were continuously imaged with BOLD sequence while a hyperoxic (70% O2 ) state was interspersed with baseline periods of normoxia...
May 28, 2018: NeuroImage
Gabriella Nyitrai, Tamás Spisák, Zsófia Spisák, Dávid Gajári, Pálma Diószegi, Tamás Zsigmond Kincses, András Czurkó
Bilateral common carotid artery occlusion (BCCAo) in the rat is a widely used animal model of vascular dementia and a valuable tool for preclinical pharmacological drug testing, although the varying degrees of acute focal ischemic lesions it induces could interfere with its translational value. Recently, a modification to the BCCAo model, the stepwise occlusion of the two carotid arteries, has been introduced. To acquire objective translatable measures, we used longitudinal multimodal magnetic resonance imaging (MRI) to assess the effects of semi-chronic (8 days) donepezil treatment in this model, with half of the Wistar rats receiving the treatment one week after the stepwise BCCAo...
2018: PloS One
Yongfang Wang, Ke Ren, Lizhi Xie, Wenge Sun, Yi Liu, Songbai Li
Purpose: To determine the optimal time interval of repeated intravenous injections of iodixanol in rat model and to identify the injury location and causes of renal damage in vivo . Materials and Methods: Rats were randomly divided into Control group, Group 1 with one iodixanol injection, and Group 2 with two iodixanol injections. Group 2 was subdivided into 3 cohorts according to the interval between the first and second iodixanol injections as 1, 3, and 5 days, respectively...
2018: BioMed Research International
A M van Opstal, A Hafkemeijer, A A van den Berg-Huysmans, M Hoeksma, C Blonk, H Pijl, S A R B Rombouts, J van der Grond
OBJECTIVES: The regulatory role of the brain in directing eating behavior becomes increasingly recognized. Although many areas in the brain have been found to respond to food cues, very little data is available after actual caloric intake. The aim of this study was to determine normal whole brain functional responses to ingestion of glucose after an overnight fast. METHODS: Twenty-five normal weight, adult males underwent functional MRI on two separate visits. In a single-blind randomized study setup, participants received either glucose solution (50 g/300 ml of water) or plain water...
May 27, 2018: Nutritional Neuroscience
Marie-Eve Muller, Menno Pruijm, Olivier Bonny, Michel Burnier, Anne Zanchi
INTRODUCTION: Empagliflozin is an SGLT-2 inhibitor (SGLT-2i) which belongs to a new class of hypoglycemic drugs with the unique property of decreasing blood glucose independently from insulin, through an increase in glycosuria. In addition to decreasing cardiovascular morbidity and mortality, empagliflozin has nephroprotective properties in high cardiovascular risk patients with type 2 diabetes. Decreased hyperfiltration and shifting towards more favorable renal fuel energetics with improved renal oxygenation may explain some of these properties...
May 25, 2018: Advances in Therapy
Pai-Feng Yang, M Anthony Phipps, Allen T Newton, Vandiver Chaplin, John C Gore, Charles F Caskey, Li Min Chen
Focused ultrasound (FUS) has gained recognition as a technique for non-invasive neuromodulation with high spatial precision and the ability to both excite and inhibit neural activity. Here we demonstrate that MRI-guided FUS is capable of exciting precise targets within areas 3a/3b in the monkey brain, causing downstream activations in off-target somatosensory and associated brain regions which are simultaneously detected by functional MRI. The similarity between natural tactile stimulation-and FUS- evoked fMRI activation patterns suggests that FUS likely can excite populations of neurons and produce associated spiking activities that may be subsequently transmitted to other functionally related touch regions...
May 22, 2018: Scientific Reports
Brian D Mills, David S Grayson, Anandakumar Shunmugavel, Oscar Miranda-Dominguez, Eric Feczko, Eric Earl, Kim Neve, Damien A Fair
Cognition and behavior depend on synchronized intrinsic brain activity that is organized into functional networks across the brain. Research has investigated how anatomical connectivity both shapes and is shaped by these networks, but not how anatomical connectivity interacts with intra-areal molecular properties to drive functional connectivity. Here, we present a novel linear model to explain functional connectivity by integrating systematically obtained measurements of axonal connectivity, gene expression, and resting state functional connectivity MRI in the mouse brain...
May 22, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Saul Jaime, Jose E Cavazos, Yihong Yang, Hanbing Lu
BACKGROUND: fMRI blood oxygenation level-dependent (BOLD) signal has been widely used as a surrogate for neural activity. However, interpreting differences in BOLD fMRI based on underlying neuronal activity remains a challenge. Concurrent rsMRI data collection and electrophysiological recording in combination with microiontophoretically injected modulatory chemicals allows for improved understanding of the relationship between resting state BOLD and neuronal activity. NEW METHODS: Simultaneous fMRI, multi-channel intracortical electrophysiology and focal pharmacological manipulation data to be acquired longitudinally in rats for up to 2 months...
May 17, 2018: Journal of Neuroscience Methods
S Tak, J Noh, C Cheong, P Zeidman, A Razi, W D Penny, K J Friston
BACKGROUND: There is growing interest in ultra-high field magnetic resonance imaging (MRI) in cognitive and clinical neuroscience studies. However, the benefits offered by higher field strength have not been evaluated in terms of effective connectivity and dynamic causal modelling (DCM). NEW METHOD: In this study, we address the validity of DCM for 7T functional MRI data at two levels. First, we evaluate the predictive validity of DCM estimates based upon 3T and 7T in terms of reproducibility...
May 11, 2018: Journal of Neuroscience Methods
Inken Rothkirch, Stephan Wolff, Nils G Margraf, Anya Pedersen, Karsten Witt
Previous studies demonstrated the influence of the post-learning period on procedural motor memory consolidation. In an early period after the acquisition, motor skills are vulnerable to modifications during wakefulness. Indeed, specific interventions such as world-list learning within this early phase of motor memory consolidation seem to enhance motor performance as an indicator for successful consolidation. This finding highlights the idea that manipulations of procedural and declarative memory systems during the early phase of memory consolidation over wakefulness may influence off-line consolidation...
2018: Frontiers in Neuroscience
Basile Pinsard, Arnaud Boutin, Julien Doyon, Habib Benali
Functional MRI acquisition is sensitive to subjects' motion that cannot be fully constrained. Therefore, signal corrections have to be applied a posteriori in order to mitigate the complex interactions between changing tissue localization and magnetic fields, gradients and readouts. To circumvent current preprocessing strategies limitations, we developed an integrated method that correct motion and spatial low-frequency intensity fluctuations at the level of each slice in order to better fit the acquisition processes...
2018: Frontiers in Neuroscience
Bing-Hua Chen, Rui Wu, Dong-Aolei An, Ruo-Yang Shi, Qiu-Ying Yao, Qing Lu, Jiani Hu, Meng Jiang, James Deen, Ankush Chandra, Jian-Rong Xu, Lian-Ming Wu
BACKGROUND: BOLD (blood oxygen level dependent) MRI can detect regional condition of myocardial oxygen supply and demand by means of paramagnetic properties. PURPOSE: Noninvasive assessment of myocardial oxygenation by BOLD MRI in hypertensive patients with hypertension (HTN) left ventricular myocardial hypertrophy (LVMH) and HTN non-LVMH and its correlation with myocardial mechanics were performed. STUDY TYPE: Prospective. POPULATION: Twenty patients with HTN LVMH, 21 patients with HTN non-LVMH, and 23 normotensive controls were enrolled...
May 7, 2018: Journal of Magnetic Resonance Imaging: JMRI
Hong-Jian Shi, Yan-Feng Li, Wen-Jie Ji, Zhi-Chun Lin, Wei Cai, Tao Chen, Bin Yuan, Xiu-Long Niu, Han-Ying Li, Wen Shu, Yu-Ming Li, Fei Yuan, Xin Zhou, Zhuoli Zhang
OBJECTIVE: This study aimed to investigate the feasibility of blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) to evaluate visceral adipose tissue (VAT) oxygenation in Zucker diabetic fatty (ZDF) rats and its associations with systemic metaflammation. METHODS: Five-week-old ZDF rats and Zucker lean (ZL) rats were fed a high-fat diet (HFD) for 18 weeks. A baseline BOLD-MRI scan of perirenal adipose tissue was performed after 8 weeks of HFD feeding, and then the rats were randomized to receive pioglitazone or a vehicle for the following 10 weeks...
May 7, 2018: Obesity
Xiao Gao, Qianlin Liang, Guorong Wu, Ying She, Nan Sui, Hong Chen
Increasing animal models as well as brain imaging studies among human suggest an association between substance-related impulsivity in decision-making and decreased function of dorsal striatum. However, the resting-state intrinsic functional organization of dorsal striatum underlying food-choice impulsivity remains unknown. To address this issue, we used resting-state functional MRI (rs-fMRI) to measure brain activity among adult females. Subjects underwent the food rating task, during which they rated each food item according to their subjective perception of its taste (from Dislike it very much to Like it very much), its long term effect on health (from very unhealthy to very healthy) and decision strength to eat it (from Strong no to Strong yes)...
April 30, 2018: Appetite
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