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C J Gauthier, A P Fan
The BOLD contrast mechanism has a complex relationship with functional brain activity, oxygen metabolism, and neurovascular factors. Accurate interpretation of the BOLD signal for neuroscience and clinical applications necessitates a clear understanding of the sources of BOLD contrast and its relationship to underlying physiology. This review describes the physiological components that contribute to the BOLD signal and the steady-state calibrated BOLD models that enable quantification of functional changes with a separate challenge paradigm...
March 12, 2018: NeuroImage
Elizabeth A Shay, Quanjing Chen, Frank E Garcea, Bradford Z Mahon
Multivoxel pattern analysis (MVPA) over functional MRI data can distinguish neural representational states that do not differ in their overall amplitude of BOLD contrast. Here we used MVPA to test whether simple intransitive actions can be distinguished in primary motor cortex. Participants rotated and flexed each of their extremities (hands and feet) during fMRI scanning. The primary motor cortex for the hand/wrist was functionally defined in each hemisphere in each subject. Within those subject-specific ROIs, we found that the average amplitude of BOLD contrast for two different movements of the contralateral hand (rotation, flexion) were higher than for the ipsilateral hand, as well as movements by both feet; however, there was no difference in amplitude between the two different types of movements for the contralateral hand...
March 16, 2018: Cognitive Neuroscience
Sebastian V Nielsen, Martin Kellner, Per G Henriksen, Håkan Olsén, Steen H Hansen, Erik Baatrup
Selective serotonin re-uptake inhibitors are pharmaceuticals used to treat a range of psychological disorders. They are frequently found in surface waters in populated areas. In recent years, they have been shown to affect the behaviour of various aquatic organisms in a way that can have ecological effects. In this study, we exposed zebrafish of both sexes to nominally 0.00, 0.15 and 1.50 µg L-1 Escitalopram in flow-through tanks for three weeks. Subsequently, ten swimming behaviour parameters were quantified using high-resolution video tracking...
March 14, 2018: Ecotoxicology
Fen Chen, Shulin Li, Dong Sun
Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) has recently been utilized as a noninvasive tool for evaluating renal oxygenation. Several methods have been proposed for analyzing BOLD images. Regional ROI selection is the earliest and most widely used method for BOLD analysis. In the last 20 years, many investigators have used this method to evaluate cortical and medullary oxygenation in patients with ischemic nephropathy, hypertensive nephropathy, diabetic nephropathy, chronic kidney disease (CKD), acute kidney injury and renal allograft rejection...
March 8, 2018: Kidney & Blood Pressure Research
Bei-Bei Wu, Ye Ma, Lei Xie, Jin-Zhuang Huang, Zong-Bo Sun, Zhi-Duo Hou, Rui-Wei Guo, Zhi-Rong Lin, Shou-Xing Duan, Shan-Shan Zhao, Yao-Xie, Dan-Miao Sun, Chun-Min Zhu, Shu-Hua Ma
BACKGROUND: Systemic lupus erythematosus (SLE) is associated with cognitive deficit but the exact neural mechanisms remain unclear. PURPOSE: To explore sequential brain activities using functional magnetic resonance imaging (fMRI) during the performance of a decision-making task, and to determine whether serum or clinical markers can reflect the involvement of the brain in SLE. SUBJECTS: Sixteen female SLE patients without overt clinical neuropsychiatric symptoms and 16 healthy controls were included...
March 14, 2018: Journal of Magnetic Resonance Imaging: JMRI
Martin Lamos, Radek Marecek, Tomáš Slavíček, Michal Mikl, Ivan Rektor, Jiri Jan
Growing interest in the examination of large-scale brain network functional connectivity dynamics is accompanied by an effort to find the electrophysiological correlates. The commonly used constraints applied to spatial and spectral domains during EEG data analysis may leave part of the neural activity unrecognized. We propose an approach that blindly reveals multimodal EEG spectral patterns that are related to the dynamics of the BOLD functional network connectivity.
 Approach. The blind decomposition of EEG spectrogram by Parallel Factor Analysis has been shown to be a useful technique for uncovering patterns of neural activity...
March 14, 2018: Journal of Neural Engineering
A C Van Erp, R A Rebolledo, D Hoeksma, N R Jespersen, P J Ottens, R Nørregaard, M Pedersen, C Laustsen, J G M Burgerhof, J C Wolters, J Ciapaite, H E Bøtker, H G D Leuvenink, B Jespersen
Hepatic and renal energy status prior to transplantation correlates with graft survival. However, effects of brain death (BD) on organ-specific energy status are largely unknown. We studied metabolism, perfusion, oxygen consumption, and mitochondrial function in the liver and kidneys following BD. BD was induced in mechanically-ventilated rats, inflating an epidurally-placed Fogarty-catheter, with sham-operated rats as controls. A 9.4T-preclinical MRI system measured hourly oxygen availability (BOLD-related R2*) and perfusion (T1-weighted)...
March 13, 2018: Scientific Reports
Pengmin Qin, Niall W Duncan, David Yen-Ting Chen, Chi-Jen Chen, Li-Kai Huang, Zirui Huang, Chien-Yuan E Lin, Christine Wiebking, Che-Ming Yang, Georg Northoff, Timothy Lane
Neural activity varies continually from moment to moment. Such temporal variability (TV) has been highlighted as a functionally specific brain property playing a fundamental role in cognition. We sought to investigate the mechanisms involved in TV changes between two basic behavioural states, namely having the eyes open (EO) or eyes closed (EC) in vivo in humans. To these ends we acquired BOLD fMRI, ASL, and [18 F]-fluoro-deoxyglucose PET in a group of healthy participants (n = 15), along with BOLD fMRI and [18 F]-flumazenil PET in a separate group (n = 19)...
March 9, 2018: Neuroscience
Logan T Dowdle, Truman R Brown, Mark S George, Colleen A Hanlon
BACKGROUND: In the 20 years since our group established the feasibility of performing interleaved TMS/fMRI, no studies have reported direct comparisons of active prefrontal stimulation with a matched sham. Thus, for all studies there is concern about what is truly the TMS effect on cortical neurons. OBJECTIVE: After developing a sham control for use within the MRI scanner, we used fMRI to test the hypothesis of greater regional BOLD responses for active versus control stimulation...
February 24, 2018: Brain Stimulation
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
Elshin Mathias, Allanah Kenny, Michael J Plank, Tim David
A state-of-the-art integrated model of neurovascular coupling (NVC) [19, 18, 38] and the BOLD response [47, 48] is presented with the ability to simulate the fMRI BOLD responses due to continuous neuronal spiking, bursting and cortical spreading depression (CSD) along with the underlying complex vascular coupling. Simulated BOLD responses are compared to experimental BOLD signals observed in the rat barrel cortex and in the hippocampus under seizure conditions showing good agreement. Bursting phenomena provides relatively clear BOLD signals as long as the time between bursts is not too short...
March 8, 2018: NeuroImage
Benjamin D Fellows, Nardine Ghobrial, Elliot Mappus, Andrew Hargett, Mark Bolding, Delphine Dean, Olin Thompson Mefford
Restenosis by neointimal hyperplasia is still an ongoing concern in endovascular surgery. Slowing vascular smooth muscle cell (VSMC) proliferation by reversing the phenotype change, would allow vessel healing and re-endotheliazation. To accomplish this, we have developed heparin-coated magnetic nanoparticles for targeted drug therapy of neointimal hyperplasia. Iron oxide nanoparticles were modified with a poly (ethylene oxide) based coating and then further functionalized with heparin. In vitro experiments were conducted to observe changes in phenotype, metabolic activity, and viability of three relevant cell lines including VSMC, endothelial cells and fibroblasts...
March 8, 2018: Nanomedicine: Nanotechnology, Biology, and Medicine
Dominique Maciejewski, Nina Lauharatanahirun, Toria Herd, Jacob Lee, Kirby Deater-Deckard, Brooks King-Casas, Jungmeen Kim-Spoon
Adolescence is a critical period for the initiation of risk-taking behaviors. We examined the longitudinal interplay between neural correlates of risk processing and cognitive control in predicting risk-taking behaviors via stress. The sample consisted of 167 adolescents (53% males) who were assessed twice (MAgeTime1  = 14.13, MAgeTime2  = 15.05). Neural risk processing was operationalized as blood-oxygen-level-dependent (BOLD) responses in the anterior insula during a lottery choice task and neural cognitive control as BOLD responses during an inhibitory control task...
February 14, 2018: Developmental Cognitive Neuroscience
Mohammad Karamouzian, Navid Madani, Fardad Doroudi, Ali Akbar Haghdoost
No abstract text is available yet for this article.
September 10, 2017: International Journal of Health Policy and Management
Catarina Amado, Polina Stoyanova, Gyula Kovács
Several electrophysiological studies found response differences to a given stimulus when it is repeated frequently as compared to when it occurs rarely in oddball sequences. Initially defined in acoustic perception, such difference also exists in the visual modality and is referred to as visual mismatch negativity (vMMN). However, the repetition of a stimulus also leads to the reduction of the blood oxygen-level dependent (BOLD) signal (fMRI adaptation, fMRIa) when compared to alternating stimuli in fMRI experiments...
March 7, 2018: Behavioural Brain Research
Fidelma Breen, John Coveney, Carol Anne Pflaum
The purpose of this article is to map the data currently available on the subject of eating practices and food environments in small (i.e. one- and two-person) households. Specifically, the enquiry is focused on commensality; the act of eating together. Research dates from the late 1980s, however, there are few recent publications on this subject. Searching Ovid MEDLINE, PsycINFO, CINAHL, Web of Science, Scopus, ProQuest and Google Scholar, 2949 papers were found, but only 457 discussed any element of the research questions...
March 6, 2018: Appetite
Teppei Matsui, Tomonari Murakami, Kenichi Ohki
Resting-state functional connectivity (FC) has become a major functional magnetic resonance imaging method to study network organization of human brains. There has been recent interest in the temporal fluctuations of FC calculated using short time windows ("dynamic FC") because this method could provide information inaccessible with conventional "static" FC, which is typically calculated using the entire scan lasting several tens of minutes. Although multiple studies have revealed considerable temporal fluctuations in FC, it is still unclear whether the fluctuations of FC measured in hemodynamics reflect the dynamics of underlying neural activity...
March 7, 2018: Cerebral Cortex
Ria Maxine Rühl, Thomas Bauermann, Marianne Dieterich, Peter Zu Eulenburg
The visual motion aftereffect (MAE) is the most prominent aftereffect in the visual system. Regarding its function, Psychophysical studies suggest its function to be a form of sensory error correction, possibly also triggered by incongruent visual-vestibular stimulation. Several observational imaging experiments have deducted an essential role for region MT+ in the perception of a visual MAE but not provided conclusive evidence. Potential confounders with the MAE such as ocular motor performance, attention, and vection sensations have also never been controlled for...
March 5, 2018: NeuroImage
Shruti G Vij, Jason S Nomi, Dina R Dajani, Lucina Q Uddin
Development and aging are associated with functional changes in the brain across the lifespan. These changes manifest in a variety of spatial and temporal features of resting state functional MRI (rs-fMRI) but have seldom been explored exhaustively. We present a comprehensive study assessing age-related changes in spatial and temporal features of blind-source separated components identified by independent vector analysis (IVA) in a cross-sectional lifespan sample (ages 6-85 years). We show that while large-scale network configurations remain consistent throughout the lifespan, changes persist in both local and global organization of these networks...
March 6, 2018: NeuroImage
Rana Ahmed, Ryan Robinson, Asma Elsony, Rachael Thomson, S Bertel Squire, Rasmus Malmborg, Peter Burney, Kevin Mortimer
INTRODUCTION: Data collection using paper-based questionnaires can be time consuming and return errors affect data accuracy, completeness, and information quality in health surveys. We compared smartphone and paper-based data collection systems in the Burden of Obstructive Lung Disease (BOLD) study in rural Sudan. METHODS: This exploratory pilot study was designed to run in parallel with the cross-sectional household survey. The Open Data Kit was used to programme questionnaires in Arabic into smartphones...
2018: PloS One
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