Fitness Consequences of Boldness in Juvenile and Adult Largemouth Bass.

Science.gov (United States)

Ballew, Nicholas G; Mittelbach, Gary G; Scribner, Kim T

2017-04-01

To date, most studies investigating the relationship between personality traits and fitness have focused on a single measure of fitness (such as survival) at a specific life stage. However, many personality traits likely have multiple effects on fitness, potentially operating across different functional contexts and stages of development. Here, we address the fitness consequences of boldness, under seminatural conditions, across life stages and functional contexts in largemouth bass (Micropterus salmoides). Specifically, we report the effect of boldness on (1) juvenile survivorship in an outdoor pond containing natural prey and predators and (2) adult reproductive success in three outdoor ponds across three reproductive seasons (years). Juvenile survival was negatively affected by boldness, with bolder juveniles having a lower probability of survival than shyer juveniles. In contrast, bolder adult male bass had greater reproductive success than their shyer male counterparts. Female reproductive success was not affected by boldness. These findings demonstrate that boldness can affect fitness differently across life stages. Further, boldness was highly consistent across years and significantly heritable, which suggests that boldness has a genetic component. Thus, our results support theory suggesting that fitness trade-offs across life stages may contribute to the maintenance of personality variation within populations.

The effect of renal denervation on kidney oxygenation as determined by BOLD MRI in patients with hypertension

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Vink, E.E.; Boer, A.; Blankestijn, P.J. [University Medical Center Utrecht, Department of Nephrology, P.O. Box 85500, GA, Utrecht (Netherlands); Verloop, W.L.; Voskuil, M. [University Medical Center Utrecht, Department of Cardiology, Utrecht (Netherlands); Spiering, W.; Leiner, T. [University Medical Center Utrecht, Department of Vascular Medicine, Utrecht (Netherlands); Vonken, E.; Hoogduin, J.M. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Bots, M.L. [University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht (Netherlands)

2015-07-15

Renal denervation (RDN) is a promising therapy for resistant hypertension. RDN is assumed to decrease sympathetic activity. Consequently, RDN can potentially increase renal oxygenation. Blood oxygen level-dependent MRI (BOLD-MRI) provides a non-invasive tool to determine renal oxygenation in humans. The aim of the current study was to investigate the effect of RDN on renal oxygenation as determined by BOLD-MRI. Patients with resistant hypertension or the inability to follow a stable drug regimen due to unacceptable side effects were included. BOLD-MRI was performed before and 12 months after RDN. Twenty-seven patients were imaged on 3 T and 19 on 1.5 T clinical MRI systems. Fifty-four patients were included, 46 patients (23 men, mean age 57 years) completed the study. Mean 24-h BP changed from 163(±20)/98(±14) mmHg to 154(±22)/92(±13) mmHg (p = 0.001 and p < 0.001). eGFR did not change after RDN [77(±18) vs. 79(±20) mL/min/1.73 m{sup 2}; p = 0.13]. RDN did not affect renal oxygenation [1.5 T: cortical R2*: 12.5(±0.9) vs. 12.5(±0.9), p = 0.94; medullary R2*: 19.6(±1.7) vs. 19.3(1.4), p = 0.40; 3 T: cortical R2*: 18.1(±0.8) vs. 17.8(±1.2), p = 0.47; medullary R2*: 27.4(±1.9) vs. 26.7(±1.8), p = 0.19]. The current study shows that RDN does not lead to changes in renal oxygenation 1 year after RDN as determined by BOLD-MRI. (orig.)

18 CFR 284.283 - Point of unbundling.

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2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Point of unbundling. 284.283 Section 284.283 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION... AUTHORITIES Blanket Certificates Authorizing Certain Natural Gas Sales by Interstate Pipelines § 284.283 Point...

Dual time point 18FDG-PET/CT versus single time point 18FDG-PET/CT for the differential diagnosis of pulmonary nodules - A meta-analysis

International Nuclear Information System (INIS)

Zhang, Li; Wang, Yinzhong; Lei, Junqiang; Tian, Jinhui; Zhai, Yanan

2013-01-01

Background: Lung cancer is one of the most common cancer types in the world. An accurate diagnosis of lung cancer is crucial for early treatment and management. Purpose: To perform a comprehensive meta-analysis to evaluate the diagnostic performance of dual time point 18F-fluorodexyglucose position emission tomography/computed tomography (FDG-PET/CT) and single time point 18FDG-PET/CT in the diagnosis of pulmonary nodules. Material and Methods: PubMed (1966-2011.11), EMBASE (1974-2011.11), Web of Science (1972-2011.11), Cochrane Library (-2011.11), and four Chinese databases; CBM (1978-2011.11), CNKI (1994-2011.11), VIP (1989-2011.11), and Wanfang Database (1994-2011.11) were searched. Summary sensitivity, summary specificity, summary diagnostic odds ratios (DOR), and summary positive likelihood ratios (LR+) and negative likelihood ratios (LR-) were obtained using Meta-Disc software. Summary receiver-operating characteristic (SROC) curves were used to evaluate the diagnostic performance of dual time point 18FDG-PET/CT and single time point 18FDG-PET/CT. Results: The inclusion criteria were fulfilled by eight articles, with a total of 415 patients and 430 pulmonary nodules. Compared with the gold standard (pathology or clinical follow-up), the summary sensitivity of dual time point 18FDG-PET/CT was 79% (95%CI, 74.0 - 84.0%), and its summary specificity was 73% (95%CI, 65.0-79.0%); the summary LR+ was 2.61 (95%CI, 1.96-3.47), and the summary LR- was 0.29 (95%CI, 0.21 - 0.41); the summary DOR was 10.25 (95%CI, 5.79 - 18.14), and the area under the SROC curve (AUC) was 0.8244. The summary sensitivity for single time point 18FDG-PET/CT was 77% (95%CI, 71.9 - 82.3%), and its summary specificity was 59% (95%CI, 50.6 - 66.2%); the summary LR+ was 1.97 (95%CI, 1.32 - 2.93), and the summary LR- was 0.37 (95%CI, 0.29 - 0.49); the summary DOR was 6.39 (95%CI, 3.39 - 12.05), and the AUC was 0.8220. Conclusion: The results indicate that dual time point 18FDG-PET/CT and single

Identifying and characterizing systematic temporally-lagged BOLD artifacts.

Science.gov (United States)

Byrge, Lisa; Kennedy, Daniel P

2018-05-01

Residual noise in the BOLD signal remains problematic for fMRI - particularly for techniques such as functional connectivity, where findings can be spuriously influenced by noise sources that can covary with individual differences. Many such potential noise sources - for instance, motion and respiration - can have a temporally lagged effect on the BOLD signal. Thus, here we present a tool for assessing residual lagged structure in the BOLD signal that is associated with nuisance signals, using a construction similar to a peri-event time histogram. Using this method, we find that framewise displacements - both large and very small - were followed by structured, prolonged, and global changes in the BOLD signal that depend on the magnitude of the preceding displacement and extend for tens of seconds. This residual lagged BOLD structure was consistent across datasets, and independently predicted considerable variance in the global cortical signal (as much as 30-40% in some subjects). Mean functional connectivity estimates varied similarly as a function of displacements occurring many seconds in the past, even after strict censoring. Similar patterns of residual lagged BOLD structure were apparent following respiratory fluctuations (which covaried with framewise displacements), implicating respiration as one likely mechanism underlying the displacement-linked structure observed. Global signal regression largely attenuates this artifactual structure. These findings suggest the need for caution in interpreting results of individual difference studies where noise sources might covary with the individual differences of interest, and highlight the need for further development of preprocessing techniques for mitigating such structure in a more nuanced and targeted manner. Copyright © 2018 Elsevier Inc. All rights reserved.

Caffeine reduces resting-state BOLD functional connectivity in the motor cortex.

Science.gov (United States)

Rack-Gomer, Anna Leigh; Liau, Joy; Liu, Thomas T

2009-05-15

In resting-state functional magnetic resonance imaging (fMRI), correlations between spontaneous low-frequency fluctuations in the blood oxygenation level dependent (BOLD) signal are used to assess functional connectivity between different brain regions. Changes in resting-state BOLD connectivity measures are typically interpreted as changes in coherent neural activity across spatially distinct brain regions. However, this interpretation can be complicated by the complex dependence of the BOLD signal on both neural and vascular factors. For example, prior studies have shown that vasoactive agents that alter baseline cerebral blood flow, such as caffeine and carbon dioxide, can significantly alter the amplitude and dynamics of the task-related BOLD response. In this study, we examined the effect of caffeine (200 mg dose) on resting-state BOLD connectivity in the motor cortex across a sample of healthy young subjects (N=9). We found that caffeine significantly (pcaffeine. These results suggest that caffeine usage should be carefully considered in the design and interpretation of resting-state BOLD fMRI studies.

BOLD magnetic resonance imaging in nephrology

Science.gov (United States)

Hall, Michael E; Jordan, Jennifer H; Juncos, Luis A; Hundley, W Gregory; Hall, John E

2018-01-01

Magnetic resonance (MR) imaging, a non-invasive modality that provides anatomic and physiologic information, is increasingly used for diagnosis of pathophysiologic conditions and for understanding renal physiology in humans. Although functional MR imaging methods were pioneered to investigate the brain, they also offer powerful techniques for investigation of other organ systems such as the kidneys. However, imaging the kidneys provides unique challenges due to potential complications from contrast agents. Therefore, development of non-contrast techniques to study kidney anatomy and physiology is important. Blood oxygen level-dependent (BOLD) MR is a non-contrast imaging technique that provides functional information related to renal tissue oxygenation in various pathophysiologic conditions. Here we discuss technical considerations, clinical uses and future directions for use of BOLD MR as well as complementary MR techniques to better understand renal pathophysiology. Our intent is to summarize kidney BOLD MR applications for the clinician rather than focusing on the complex physical challenges that functional MR imaging encompasses; however, we briefly discuss some of those issues. PMID:29559807

Blood oxygenation level dependent (BOLD). Renal imaging. Concepts and applications; Blood Oxygenation Level Dependent (BOLD). Bildgebung der Nieren. Konzepte und Anwendungen

Energy Technology Data Exchange (ETDEWEB)

Nissen, Johanna C.; Haneder, Stefan; Schoenberg, Stefan O.; Michaely, Henrik J. [Heidelberg Univ. Medizinische Fakultaet Mannheim (Germany). Inst. fuer Klinische Radiologie und Nuklearmedizin; Mie, Moritz B.; Zoellner, Frank G. [Heidelberg Univ. Medizinische Fakultaet Mannheim (DE). Inst. fuer Computerunterstuetzte Klinische Medizin (CKM)

2010-07-01

Many renal diseases as well as several pharmacons cause a change in renal blood flow and/or renal oxygenation. The blood oxygenation level dependent (BOLD) imaging takes advantage of local field inhomogeneities and is based on a T2{sup *}-weighted sequence. BOLD is a non-invasive method allowing an estimation of the renal, particularly the medullary oxygenation, and an indirect measurement of blood flow without administration of contrast agents. Thus, effects of different drugs on the kidney and various renal diseases can be controlled and observed. This work will provide an overview of the studies carried out so far and identify ways how BOLD can be used in clinical studies. (orig.)

Placental baseline conditions modulate the hyperoxic BOLD-MRI response.

Science.gov (United States)

Sinding, Marianne; Peters, David A; Poulsen, Sofie S; Frøkjær, Jens B; Christiansen, Ole B; Petersen, Astrid; Uldbjerg, Niels; Sørensen, Anne

2018-01-01

Human pregnancies complicated by placental dysfunction may be characterized by a high hyperoxic Blood oxygen level-dependent (BOLD) MRI response. The pathophysiology behind this phenomenon remains to be established. The aim of this study was to evaluate whether it is associated with altered placental baseline conditions, including a lower oxygenation and altered tissue morphology, as estimated by the placental transverse relaxation time (T2*). We included 49 normal pregnancies (controls) and 13 pregnancies complicated by placental dysfunction (cases), defined by a birth weight baseline BOLD)/baseline BOLD) from a dynamic single-echo gradient-recalled echo (GRE) MRI sequence and the absolute ΔT2* (hyperoxic T2*- baseline T2*) from breath-hold multi-echo GRE sequences. In the control group, the relative ΔBOLD response increased during gestation from 5% in gestational week 20 to 20% in week 40. In the case group, the relative ΔBOLD response was significantly higher (mean Z-score 4.94; 95% CI 2.41, 7.47). The absolute ΔT2*, however, did not differ between controls and cases (p = 0.37), whereas the baseline T2* was lower among cases (mean Z-score -3.13; 95% CI -3.94, -2.32). Furthermore, we demonstrated a strong negative linear correlation between the Log 10 ΔBOLD response and the baseline T2* (r = -0.88, p baseline conditions, as the absolute increase in placental oxygenation (ΔT2*) does not differ between groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

Brain functional BOLD perturbation modelling for forward fMRI and inverse mapping

Science.gov (United States)

Robinson, Jennifer; Calhoun, Vince

2018-01-01

Purpose To computationally separate dynamic brain functional BOLD responses from static background in a brain functional activity for forward fMRI signal analysis and inverse mapping. Methods A brain functional activity is represented in terms of magnetic source by a perturbation model: χ = χ0 +δχ, with δχ for BOLD magnetic perturbations and χ0 for background. A brain fMRI experiment produces a timeseries of complex-valued images (T2* images), whereby we extract the BOLD phase signals (denoted by δP) by a complex division. By solving an inverse problem, we reconstruct the BOLD δχ dataset from the δP dataset, and the brain χ distribution from a (unwrapped) T2* phase image. Given a 4D dataset of task BOLD fMRI, we implement brain functional mapping by temporal correlation analysis. Results Through a high-field (7T) and high-resolution (0.5mm in plane) task fMRI experiment, we demonstrated in detail the BOLD perturbation model for fMRI phase signal separation (P + δP) and reconstructing intrinsic brain magnetic source (χ and δχ). We also provided to a low-field (3T) and low-resolution (2mm) task fMRI experiment in support of single-subject fMRI study. Our experiments show that the δχ-depicted functional map reveals bidirectional BOLD χ perturbations during the task performance. Conclusions The BOLD perturbation model allows us to separate fMRI phase signal (by complex division) and to perform inverse mapping for pure BOLD δχ reconstruction for intrinsic functional χ mapping. The full brain χ reconstruction (from unwrapped fMRI phase) provides a new brain tissue image that allows to scrutinize the brain tissue idiosyncrasy for the pure BOLD δχ response through an automatic function/structure co-localization. PMID:29351339

Brain functional BOLD perturbation modelling for forward fMRI and inverse mapping.

Science.gov (United States)

Chen, Zikuan; Robinson, Jennifer; Calhoun, Vince

2018-01-01

To computationally separate dynamic brain functional BOLD responses from static background in a brain functional activity for forward fMRI signal analysis and inverse mapping. A brain functional activity is represented in terms of magnetic source by a perturbation model: χ = χ0 +δχ, with δχ for BOLD magnetic perturbations and χ0 for background. A brain fMRI experiment produces a timeseries of complex-valued images (T2* images), whereby we extract the BOLD phase signals (denoted by δP) by a complex division. By solving an inverse problem, we reconstruct the BOLD δχ dataset from the δP dataset, and the brain χ distribution from a (unwrapped) T2* phase image. Given a 4D dataset of task BOLD fMRI, we implement brain functional mapping by temporal correlation analysis. Through a high-field (7T) and high-resolution (0.5mm in plane) task fMRI experiment, we demonstrated in detail the BOLD perturbation model for fMRI phase signal separation (P + δP) and reconstructing intrinsic brain magnetic source (χ and δχ). We also provided to a low-field (3T) and low-resolution (2mm) task fMRI experiment in support of single-subject fMRI study. Our experiments show that the δχ-depicted functional map reveals bidirectional BOLD χ perturbations during the task performance. The BOLD perturbation model allows us to separate fMRI phase signal (by complex division) and to perform inverse mapping for pure BOLD δχ reconstruction for intrinsic functional χ mapping. The full brain χ reconstruction (from unwrapped fMRI phase) provides a new brain tissue image that allows to scrutinize the brain tissue idiosyncrasy for the pure BOLD δχ response through an automatic function/structure co-localization.

Systematic protocol for assessment of the validity of BOLD MRI in a rabbit model of inflammatory arthritis at 1.5 tesla

Energy Technology Data Exchange (ETDEWEB)

Chan, Michael W.; Nathanael, George; Kis, Antonella; Amirabadi, Afsaneh; Zhong, Anguo; Rayner, Tammy; Weiss, Ruth; Detzler, Garry; Gahunia, Harpal [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Jong, Roland [Mount Sinai Hospital, Department of Pathology and Laboratory Medicine, Toronto (Canada); Moineddin, Rahim [Family and Community Medicine, Department of Public Health, Toronto (Canada); Crawley, Adrian [University of Toronto, Department of Medical Imaging, Toronto (Canada); Toronto Western Hospital, Department of Medical Imaging, Toronto (Canada); Doria, Andrea S. [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); University of Toronto, Department of Medical Imaging, Toronto (Canada)

2014-05-15

Blood-oxygen-level-dependent (BOLD) MRI has the potential to identify regions of early hypoxic and vascular joint changes in inflammatory arthritis. There is no standard protocol for analysis of BOLD MRI measurements in musculoskeletal disorders. To optimize the following BOLD MRI reading parameters: (1) statistical threshold values (low, r > 0.01 versus high, r > 0.2); (2) summary measures of BOLD contrast (percentage of activated voxels [PT%] versus percentage signal difference between on-and-off signal intensities [diff{sub o}n{sub o}ff]); and (3) direction of BOLD response (positive, negative and positive + negative). Using BOLD MRI protocols at 1.5 T, arthritic (n = 21) and contralateral (n = 21) knees of 21 juvenile rabbits were imaged at baseline and on days 1, 14 and 28 after a unilateral intra-articular injection of carrageenan. Nine non-injected rabbits served as external control knees (n = 18). By comparing arthritic to contralateral knees, receiver operating characteristic curves were used to determine diagnostic accuracy. Using diff{sub o}n{sub o}ff and positive + negative responses, a threshold of r > 0.01 was more accurate than r > 0.2 (P = 0.03 at day 28). Comparison of summary measures yielded no statistically significant difference (P > 0.05). Although positive + negative (AUC = 0.86 at day 28) and negative responses (AUC = 0.90 at day 28) for PT% were the most diagnostically accurate, positive + negative responses for diff{sub o}n{sub o}ff (AUC = 0.78 at day 28) also had acceptable accuracy. The most clinically relevant reading parameters included a lower threshold of r > 0.01 and a positive + negative BOLD response. We propose that diff{sub o}n{sub o}ff is a more clinically relevant summary measure of BOLD MRI, while PT% can be used as an ancillary measure. (orig.)

Cerebral Metabolic Rate of Oxygen (CMRO2 ) Mapping by Combining Quantitative Susceptibility Mapping (QSM) and Quantitative Blood Oxygenation Level-Dependent Imaging (qBOLD).

Science.gov (United States)

Cho, Junghun; Kee, Youngwook; Spincemaille, Pascal; Nguyen, Thanh D; Zhang, Jingwei; Gupta, Ajay; Zhang, Shun; Wang, Yi

2018-03-07

To map the cerebral metabolic rate of oxygen (CMRO 2 ) by estimating the oxygen extraction fraction (OEF) from gradient echo imaging (GRE) using phase and magnitude of the GRE data. 3D multi-echo gradient echo imaging and perfusion imaging with arterial spin labeling were performed in 11 healthy subjects. CMRO 2 and OEF maps were reconstructed by joint quantitative susceptibility mapping (QSM) to process GRE phases and quantitative blood oxygen level-dependent (qBOLD) modeling to process GRE magnitudes. Comparisons with QSM and qBOLD alone were performed using ROI analysis, paired t-tests, and Bland-Altman plot. The average CMRO 2 value in cortical gray matter across subjects were 140.4 ± 14.9, 134.1 ± 12.5, and 184.6 ± 17.9 μmol/100 g/min, with corresponding OEFs of 30.9 ± 3.4%, 30.0 ± 1.8%, and 40.9 ± 2.4% for methods based on QSM, qBOLD, and QSM+qBOLD, respectively. QSM+qBOLD provided the highest CMRO 2 contrast between gray and white matter, more uniform OEF than QSM, and less noisy OEF than qBOLD. Quantitative CMRO 2 mapping that fits the entire complex GRE data is feasible by combining QSM analysis of phase and qBOLD analysis of magnitude. © 2018 International Society for Magnetic Resonance in Medicine.

Developmental changes of BOLD signal correlations with global human EEG power and synchronization during working memory.

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Lars Michels

Full Text Available In humans, theta band (5-7 Hz power typically increases when performing cognitively demanding working memory (WM tasks, and simultaneous EEG-fMRI recordings have revealed an inverse relationship between theta power and the BOLD (blood oxygen level dependent signal in the default mode network during WM. However, synchronization also plays a fundamental role in cognitive processing, and the level of theta and higher frequency band synchronization is modulated during WM. Yet, little is known about the link between BOLD, EEG power, and EEG synchronization during WM, and how these measures develop with human brain maturation or relate to behavioral changes. We examined EEG-BOLD signal correlations from 18 young adults and 15 school-aged children for age-dependent effects during a load-modulated Sternberg WM task. Frontal load (in-dependent EEG theta power was significantly enhanced in children compared to adults, while adults showed stronger fMRI load effects. Children demonstrated a stronger negative correlation between global theta power and the BOLD signal in the default mode network relative to adults. Therefore, we conclude that theta power mediates the suppression of a task-irrelevant network. We further conclude that children suppress this network even more than adults, probably from an increased level of task-preparedness to compensate for not fully mature cognitive functions, reflected in lower response accuracy and increased reaction time. In contrast to power, correlations between instantaneous theta global field synchronization and the BOLD signal were exclusively positive in both age groups but only significant in adults in the frontal-parietal and posterior cingulate cortices. Furthermore, theta synchronization was weaker in children and was--in contrast to EEG power--positively correlated with response accuracy in both age groups. In summary we conclude that theta EEG-BOLD signal correlations differ between spectral power and

Multi-regional investigation of the relationship between functional MRI blood oxygenation level dependent (BOLD activation and GABA concentration.

Directory of Open Access Journals (Sweden)

Ashley D Harris

Full Text Available Several recent studies have reported an inter-individual correlation between regional GABA concentration, as measured by MRS, and the amplitude of the functional blood oxygenation level dependent (BOLD response in the same region. In this study, we set out to investigate whether this coupling generalizes across cortex. In 18 healthy participants, we performed edited MRS measurements of GABA and BOLD-fMRI experiments using regionally related activation paradigms. Regions and tasks were the: occipital cortex with a visual grating stimulus; auditory cortex with a white noise stimulus; sensorimotor cortex with a finger-tapping task; frontal eye field with a saccade task; and dorsolateral prefrontal cortex with a working memory task. In contrast to the prior literature, no correlation between GABA concentration and BOLD activation was detected in any region. The origin of this discrepancy is not clear. Subtle differences in study design or insufficient power may cause differing results; these and other potential reasons for the discrepant results are discussed. This negative result, although it should be interpreted with caution, has a larger sample size than prior positive results, and suggests that the relationship between GABA and the BOLD response may be more complex than previously thought.

Generate the scale-free brain music from BOLD signals.

Science.gov (United States)

Lu, Jing; Guo, Sijia; Chen, Mingming; Wang, Weixia; Yang, Hua; Guo, Daqing; Yao, Dezhong

2018-01-01

Many methods have been developed to translate a human electroencephalogram (EEG) into music. In addition to EEG, functional magnetic resonance imaging (fMRI) is another method used to study the brain and can reflect physiological processes. In 2012, we established a method to use simultaneously recorded fMRI and EEG signals to produce EEG-fMRI music, which represents a step toward scale-free brain music. In this study, we used a neural mass model, the Jansen-Rit model, to simulate activity in several cortical brain regions. The interactions between different brain regions were represented by the average normalized diffusion tensor imaging (DTI) structural connectivity with a coupling coefficient that modulated the coupling strength. Seventy-eight brain regions were adopted from the Automated Anatomical Labeling (AAL) template. Furthermore, we used the Balloon-Windkessel hemodynamic model to transform neural activity into a blood-oxygen-level dependent (BOLD) signal. Because the fMRI BOLD signal changes slowly, we used a sampling rate of 250 Hz to produce the temporal series for music generation. Then, the BOLD music was generated for each region using these simulated BOLD signals. Because the BOLD signal is scale free, these music pieces were also scale free, which is similar to classic music. Here, to simulate the case of an epileptic patient, we changed the parameter that determined the amplitude of the excitatory postsynaptic potential (EPSP) in the neural mass model. Finally, we obtained BOLD music for healthy and epileptic patients. The differences in levels of arousal between the 2 pieces of music may provide a potential tool for discriminating the different populations if the differences can be confirmed by more real data. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Hemodynamic modelling of BOLD fMRI - A machine learning approach

DEFF Research Database (Denmark)

Jacobsen, Danjal Jakup

2007-01-01

This Ph.D. thesis concerns the application of machine learning methods to hemodynamic models for BOLD fMRI data. Several such models have been proposed by different researchers, and they have in common a basis in physiological knowledge of the hemodynamic processes involved in the generation...... of the BOLD signal. The BOLD signal is modelled as a non-linear function of underlying, hidden (non-measurable) hemodynamic state variables. The focus of this thesis work has been to develop methods for learning the parameters of such models, both in their traditional formulation, and in a state space...... formulation. In the latter, noise enters at the level of the hidden states, as well as in the BOLD measurements themselves. A framework has been developed to allow approximate posterior distributions of model parameters to be learned from real fMRI data. This is accomplished with Markov chain Monte Carlo...

The BOLD cerebrovascular reactivity response to progressive hypercapnia in young and elderly

DEFF Research Database (Denmark)

Bhogal, Alex A.; De Vis, Jill B.; Siero, Jeroen C.W.

2016-01-01

to broaden our interpretation of the BOLD-CVR response. Significant age-related differences were observed. Grey matter CVR at 7 mm Hg above resting PetCO2 was lower amongst elderly (0.19 ± 0.06%ΔBOLD/mm Hg) as compared to young subjects (0.26 ± 0.07%ΔBOLD/mm Hg). White matter CVR at 7 mm Hg above baseline...

Prospective MR image alignment between breath-holds: Application to renal BOLD MRI.

Science.gov (United States)

Kalis, Inge M; Pilutti, David; Krafft, Axel J; Hennig, Jürgen; Bock, Michael

2017-04-01

To present an image registration method for renal blood oxygen level-dependent (BOLD) measurements that enables semiautomatic assessment of parenchymal and medullary R2* changes under a functional challenge. In a series of breath-hold acquisitions, three-dimensional data were acquired initially for prospective image registration of subsequent BOLD measurements. An algorithm for kidney alignment for BOLD renal imaging (KALIBRI) was implemented to detect the positions of the left and right kidney so that the kidneys were acquired in the subsequent BOLD measurement at consistent anatomical locations. Residual in-plane distortions were corrected retrospectively so that semiautomatic dynamic R2* measurements of the renal cortex and medulla become feasible. KALIBRI was tested in six healthy volunteers during a series of BOLD experiments, which included a 600- to 1000-mL water challenge. Prospective image registration and BOLD imaging of each kidney was achieved within a total measurement time of about 17 s, enabling its execution within a single breath-hold. KALIBRI improved the registration by up to 35% as found with mutual information measures. In four volunteers, a medullary R2* decrease of up to 40% was observed after water ingestion. KALIBRI improves the quality of two-dimensional time-resolved renal BOLD MRI by aligning local renal anatomy, which allows for consistent R2* measurements over many breath-holds. Magn Reson Med 77:1573-1582, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Blood oxygenation level dependent (BOLD). Renal imaging. Concepts and applications

International Nuclear Information System (INIS)

Nissen, Johanna C.; Haneder, Stefan; Schoenberg, Stefan O.; Michaely, Henrik J.

2010-01-01

Many renal diseases as well as several pharmacons cause a change in renal blood flow and/or renal oxygenation. The blood oxygenation level dependent (BOLD) imaging takes advantage of local field inhomogeneities and is based on a T2 * -weighted sequence. BOLD is a non-invasive method allowing an estimation of the renal, particularly the medullary oxygenation, and an indirect measurement of blood flow without administration of contrast agents. Thus, effects of different drugs on the kidney and various renal diseases can be controlled and observed. This work will provide an overview of the studies carried out so far and identify ways how BOLD can be used in clinical studies. (orig.)

Functional BOLD MRI: comparison of different field strengths in a motor task

International Nuclear Information System (INIS)

Meindl, T.; Born, C.; Britsch, S.; Reiser, M.; Schoenberg, S.

2008-01-01

The purpose was to evaluate the benefit of an increased field strength for functional magnetic resonance imaging in a motor task. Six right-handed volunteers were scanned at 1.5 T and 3.0 T using a motor task. Each experiment consisted of two runs with four activation blocks, each with right- and left-hand tapping. Analysis was done using BrainVoyagerQX registered . Differences between both field strengths concerning signal to noise (SNR), blood oxygen level-dependent (BOLD) signal change, functional sensitivity and BOLD contrast to noise (CNR) were tested using a paired t test. Delineation of activations and artifacts were graded by two independent readers. Results were further validated by means of a phantom study. The sensorimotor and premotor cortex, the supplementary motor area, subcortical and cerebellar structures were activated at each field strength. Additional activations of the right premotor cortex and right superior temporal gyrus were found at 3.0 T. Signal-to-noise, percentage of BOLD signal change, BOLD CNR and functional sensitivity improved at 3.0 T by a factor of up to 2.4. Functional imaging at 3.0 T results in detection of additional activated areas, increased SNR, BOLD signal change, functional sensitivity and BOLD CNR. (orig.)

Detection of Rickettsia hoogstraalii, Rickettsia helvetica, Rickettsia massiliae, Rickettsia slovaca and Rickettsia aeschlimannii in ticks from Sardinia, Italy.

Science.gov (United States)

Chisu, Valentina; Leulmi, Hamza; Masala, Giovanna; Piredda, Mariano; Foxi, Cipriano; Parola, Philippe

2017-03-01

Tick-borne diseases represent a large proportion of infectious diseases that have become a world health concern. The presence of Rickettsia spp. was evaluated by standard PCR and sequencing in 123 ticks collected from several mammals and vegetation in Sardinia, Italy. This study provides the first evidence of the presence of Rickettsia hoogstralii in Haemaphysalis punctata and Haemaphysalis sulcata ticks from mouflon and Rickettsia helvetica in Ixodes festai ticks from hedgehog. In addition, Rickettsia massiliae, Rickettsia slovaca and Rickettsia aeschlimannii were detected in Rhipicephalus sanguineus, Dermacentor marginatus and Hyalomma marginatum marginatum ticks from foxes, swine, wild boars, and mouflon. The data presented here increase our knowledge of tick-borne diseases in Sardinia and provide a useful contribution toward understanding their epidemiology. Copyright © 2016 Elsevier GmbH. All rights reserved.

Metabolic Changes Underlying Bold Signal Variations after Administration of Zolpidem

International Nuclear Information System (INIS)

Rodriguez-Rojas, Rafael; Machado, Calixto; Alvarez, Lazaro; Carballo, Maylen; Perez-Nellar, Jesus; Estevez, Mario; Pavon, Nancy; Chinchilla, Mauricio

2010-12-01

Zolpidem is a non-benzodiazepine drug belonging to the imidazopiridine class, which has selectivity for stimulating the effect of gamma aminobutyric acid [GABA] and is used for the therapy of insomnia. Nonetheless, several reports have been published over recent years about a paradoxical arousing effect of Zolpidem in patients with severe brain damage. We studied a PVS case using 1 H-MRS and BOLD signal, before and after Zolpidem administration. Significantly increased BOLD signal was localized in left frontal superior cortex, bilateral cingulated areas, left thalamus and right head of the caudate nucleus. A transient activation was observed in frontal cortex, comprising portions of anterior cingulate, medial, and orbito-frontal cortices. Additionally, significant pharmacological activation in sensory-motor cortex is observed 1 hour after Zolpidem intake. Significant linear correlations of BOLD signal changes were found with primary concentrations of NAA, Glx and Lac in the right frontal cortex. We discussed that when Zolpidem attaches to the modified GABA receptors of the neurodormant cells, dormancy is switched off, inducing brain activation. This might explain the significant correlations of BOLD signal changes and 1 H-MRS metabolites in our patient. We concluded that 1 H-MRS and BOLD signal assessment might contribute to study neurovascular coupling in PVS cases after Zolpidem administration. Although this is a report of a single case, considering our results we recommend to apply this methodology in series of PVS and MCS patients. (author)

Volumetric BOLD fMRI simulation: from neurovascular coupling to multivoxel imaging

International Nuclear Information System (INIS)

Chen, Zikuan; Calhoun, Vince

2012-01-01

The blood oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI) modality has been numerically simulated by calculating single voxel signals. However, the observation on single voxel signals cannot provide information regarding the spatial distribution of the signals. Specifically, a single BOLD voxel signal simulation cannot answer the fundamental question: is the magnetic resonance (MR) image a replica of its underling magnetic susceptibility source? In this paper, we address this problem by proposing a multivoxel volumetric BOLD fMRI simulation model and a susceptibility expression formula for linear neurovascular coupling process, that allow us to examine the BOLD fMRI procedure from neurovascular coupling to MR image formation. Since MRI technology only senses the magnetism property, we represent a linear neurovascular-coupled BOLD state by a magnetic susceptibility expression formula, which accounts for the parameters of cortical vasculature, intravascular blood oxygenation level, and local neuroactivity. Upon the susceptibility expression of a BOLD state, we carry out volumetric BOLD fMRI simulation by calculating the fieldmap (established by susceptibility magnetization) and the complex multivoxel MR image (by intravoxel dephasing). Given the predefined susceptibility source and the calculated complex MR image, we compare the MR magnitude (phase, respectively) image with the predefined susceptibility source (the calculated fieldmap) by spatial correlation. The spatial correlation between the MR magnitude image and the magnetic susceptibility source is about 0.90 for the settings of T E = 30 ms, B 0 = 3 T, voxel size = 100 micron, vessel radius = 3 micron, and blood volume fraction = 2%. Using these parameters value, the spatial correlation between the MR phase image and the susceptibility-induced fieldmap is close to 1.00. Our simulation results show that the MR magnitude image is not an exact replica of the magnetic susceptibility

BOLD magnetic resonance imaging in nephrology

Directory of Open Access Journals (Sweden)

Hall ME

2018-03-01

Full Text Available Michael E Hall,1,2 Jennifer H Jordan,3 Luis A Juncos,1,2 W Gregory Hundley,3 John E Hall2 1Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA; 2Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA; 3Department of Internal Medicine, Section on Cardiovascular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA Abstract: Magnetic resonance (MR imaging, a non-invasive modality that provides anatomic and physiologic information, is increasingly used for diagnosis of pathophysiologic conditions and for understanding renal physiology in humans. Although functional MR imaging methods were pioneered to investigate the brain, they also offer powerful techniques for investigation of other organ systems such as the kidneys. However, imaging the kidneys provides unique challenges due to potential complications from contrast agents. Therefore, development of non-contrast techniques to study kidney anatomy and physiology is important. Blood oxygen level-dependent (BOLD MR is a non-contrast imaging technique that provides functional information related to renal tissue oxygenation in various pathophysiologic conditions. Here we discuss technical considerations, clinical uses and future directions for use of BOLD MR as well as complementary MR techniques to better understand renal pathophysiology. Our intent is to summarize kidney BOLD MR applications for the clinician rather than focusing on the complex physical challenges that functional MR imaging encompasses; however, we briefly discuss some of those issues. Keywords: functional MRI, kidney, oxygenation, chronic kidney disease 

Task effects on BOLD signal correlates of implicit syntactic processing

Science.gov (United States)

Caplan, David

2010-01-01

BOLD signal was measured in sixteen participants who made timed font change detection judgments in visually presented sentences that varied in syntactic structure and the order of animate and inanimate nouns. Behavioral data indicated that sentences were processed to the level of syntactic structure. BOLD signal increased in visual association areas bilaterally and left supramarginal gyrus in the contrast of sentences with object- and subject-extracted relative clauses without font changes in which the animacy order of the nouns biased against the syntactically determined meaning of the sentence. This result differs from the findings in a non-word detection task (Caplan et al, 2008a), in which the same contrast led to increased BOLD signal in the left inferior frontal gyrus. The difference in areas of activation indicates that the sentences were processed differently in the two tasks. These differences were further explored in an eye tracking study using the materials in the two tasks. Issues pertaining to how parsing and interpretive operations are affected by a task that is being performed, and how this might affect BOLD signal correlates of syntactic contrasts, are discussed. PMID:20671983

Analysis of Time and Space Invariance of BOLD Responses in the Rat Visual System

DEFF Research Database (Denmark)

Bailey, Christopher; Sanganahalli, Basavaraju G; Herman, Peter

2012-01-01

Neuroimaging studies of functional magnetic resonance imaging (fMRI) and electrophysiology provide the linkage between neural activity and the blood oxygenation level-dependent (BOLD) response. Here, BOLD responses to light flashes were imaged at 11.7T and compared with neural recordings from...... for general linear modeling (GLM) of BOLD responses. Light flashes induced high magnitude neural/BOLD responses reproducibly from both regions. However, neural/BOLD responses from SC and V1 were markedly different. SC signals followed the boxcar shape of the stimulation paradigm at all flash rates, whereas V1...... signals were characterized by onset/offset transients that exhibited different flash rate dependencies. We find that IRF(SC) is generally time-invariant across wider flash rate range compared with IRF(V1), whereas IRF(SC) and IRF(V1) are both space invariant. These results illustrate the importance...

SharePoint 2010 at Work Tricks, Traps, and Bold Opinions

CERN Document Server

Miller, Mark; Anderson, Marc; Rogers, Laura; Abraham, Kerri; Buren, Sadalit; Mastykarz, Waldek; Alexander, Eric; Bautz, Alexander; Howard, Jim; Allen, Peter

2012-01-01

If you're a SharePoint site manager or administrator, you finally have a handy single-source reference to help you through the tough SharePoint learning curve. Written by Mark Miller and his stable of well-known contributors at EndUserSharePoint.com, this book contains the most helpful articles from this popular site-fully updated for SharePoint 2010. Each chapter focuses on core issues that vex SharePoint administrators when it comes to setting up and managing sites. You'll learn tried-and-true solutions for creating charts and graphs, joining views in SharePoint lists, building a SharePoin

Decreased BOLD responses in audiovisual processing

NARCIS (Netherlands)

Wiersinga-Post, Esther; Tomaskovic, Sonja; Slabu, Lavinia; Renken, Remco; de Smit, Femke; Duifhuis, Hendrikus

2010-01-01

Audiovisual processing was studied in a functional magnetic resonance imaging study using the McGurk effect. Perceptual responses and the brain activity patterns were measured as a function of audiovisual delay. In several cortical and subcortical brain areas, BOLD responses correlated negatively

BOLD cardiovascular magnetic resonance at 3.0 tesla in myocardial ischemia.

Science.gov (United States)

Manka, Robert; Paetsch, Ingo; Schnackenburg, Bernhard; Gebker, Rolf; Fleck, Eckart; Jahnke, Cosima

2010-09-22

The purpose of this study was to determine the ability of blood oxygen level dependent (BOLD) cardiovascular magnetic resonance (CMR) to detect stress-inducible myocardial ischemic reactions in the presence of angiographically significant coronary artery disease (CAD). Forty-six patients (34 men; age 65 ± 9 years,) with suspected or known coronary artery disease underwent CMR at 3Tesla prior to clinically indicated invasive coronary angiography. BOLD CMR was performed in 3 short axis slices of the heart at rest and during adenosine stress (140 μg/kg/min) followed by late gadolinium enhancement (LGE) imaging. In all 16 standard myocardial segments, T2* values were derived at rest and under adenosine stress. Quantitative coronary angiography served as the standard of reference and defined normal myocardial segments (i.e. all 16 segments in patients without any CAD), ischemic segments (i.e. supplied by a coronary artery with ≥50% luminal narrowing) and non-ischemic segments (i.e. supplied by a non-significantly stenosed coronary artery in patients with significant CAD). Coronary angiography demonstrated significant CAD in 23 patients. BOLD CMR at rest revealed significantly lower T2* values for ischemic segments (26.7 ± 11.6 ms) compared to normal (31.9 ± 11.9 ms; p BOLD CMR at 3Tesla proved feasible and differentiated between ischemic, non-ischemic, and normal myocardial segments in a clinical patient population. BOLD CMR during vasodilator stress identified patients with significant CAD.

Non-invasive multiparametric qBOLD approach for robust mapping of the oxygen extraction fraction.

Science.gov (United States)

Domsch, Sebastian; Mie, Moritz B; Wenz, Frederik; Schad, Lothar R

2014-09-01

The quantitative blood oxygenation level-dependent (qBOLD) method has not become clinically established yet because long acquisition times are necessary to achieve an acceptable certainty of the parameter estimates. In this work, a non-invasive multiparametric (nimp) qBOLD approach based on a simple analytical model is proposed to facilitate robust oxygen extraction fraction (OEF) mapping within clinically acceptable acquisition times by using separate measurements. The protocol consisted of a gradient-echo sampled spin-echo sequence (GESSE), a T2-weighted Carr-Purcell-Meiboom-Gill (CPMG) sequence, and a T2(*)-weighted multi-slice multi-echo gradient echo (MMGE) sequence. The GESSE acquisition time was less than 5 minutes and the extra measurement time for CPMG/MMGE was below 2 minutes each. The proposed nimp-qBOLD approach was validated in healthy subjects (N = 5) and one patient. The proposed nimp-qBOLD approach facilitated more robust OEF mapping with significantly reduced inter- and intra-subject variability compared to the standard qBOLD method. Thereby, an average OEF in all subjects of 27±2% in white matter (WM) and 29±2% in gray matter (GM) using the nimp-qBOLD method was more stable compared to 41±10% (WM) and 46±10% (GM) with standard qBOLD. Moreover, the spatial variance in the image slice (i.e. standard deviation divided by mean) was on average reduced from 35% to 25%. In addition, the preliminary results of the patient are encouraging. The proposed nimp-qBOLD technique provides a promising tool for robust OEF mapping within clinically acceptable acquisition times and could therefore provide an important contribution for analyzing tumors or monitoring the success of radio and chemo therapies. Copyright © 2014. Published by Elsevier GmbH.

Non-invasive multiparametric qBOLD approach for robust mapping of the oxygen extraction fraction

Energy Technology Data Exchange (ETDEWEB)

Domsch, Sebastian; Mie, Moritz B.; Schad, Lothar R. [Heidelberg Univ., Medical Faculty Mannheim (Germany). Computer Assisted Clinical Medicine; Wenz, Frederik [Heidelberg Univ., Medical Faculty Mannheim (Germany). Dept. of Radiation Oncology

2014-10-01

Introduction: The quantitative blood oxygenation level-dependent (qBOLD) method has not become clinically established yet because long acquisition times are necessary to achieve an acceptable certainty of the parameter estimates. In this work, a non-invasive multiparametric (nimp) qBOLD approach based on a simple analytical model is proposed to facilitate robust oxygen extraction fraction (OEF) mapping within clinically acceptable acquisition times by using separate measurements. Methods: The protocol consisted of a gradient-echo sampled spin-echo sequence (GESSE), a T{sub 2}-weighted Carr-Purcell-Meiboom-Gill (CPMG) sequence, and a T{sub 2}{sup *}-weighted multi-slice multi-echo gradient echo (MMGE) sequence. The GESSE acquisition time was less than 5 minutes and the extra measurement time for CPMG / MMGE was below 2 minutes each. The proposed nimp-qBOLD approach was validated in healthy subjects (N = 5) and one patient. Results: The proposed nimp-qBOLD approach facilitated more robust OEF mapping with significantly reduced inter- and intra-subject variability compared to the standard qBOLD method. Thereby, an average OEF in all subjects of 27 ± 2 % in white matter (WM) and 29 ± 2 % in gray matter (GM) using the nimp-qBOLD method was more stable compared to 41 ± 10 % (WM) and 46 ± 10 % (GM) with standard qBOLD. Moreover, the spatial variance in the image slice (i.e. standard deviation divided by mean) was on average reduced from 35 % to 25 %. In addition, the preliminary results of the patient are encouraging. Conclusion: The proposed nimp-qBOLD technique provides a promising tool for robust OEF mapping within clinically acceptable acquisition times and could therefore provide an important contribution for analyzing tumors or monitoring the success of radio and chemo therapies. (orig.)

BOLD repetition decreases in object-responsive ventral visual areas depend on spatial attention.

Science.gov (United States)

Eger, E; Henson, R N A; Driver, J; Dolan, R J

2004-08-01

Functional imaging studies of priming-related repetition phenomena have become widely used to study neural object representation. Although blood oxygenation level-dependent (BOLD) repetition decreases can sometimes be observed without awareness of repetition, any role for spatial attention in BOLD repetition effects remains largely unknown. We used fMRI in 13 healthy subjects to test whether BOLD repetition decreases for repeated objects in ventral visual cortices depend on allocation of spatial attention to the prime. Subjects performed a size-judgment task on a probe object that had been attended or ignored in a preceding prime display of 2 lateralized objects. Reaction times showed faster responses when the probe was the same object as the attended prime, independent of the view tested (identical vs. mirror image). No behavioral effect was evident from unattended primes. BOLD repetition decreases for attended primes were found in lateral occipital and fusiform regions bilaterally, which generalized across identical and mirror-image repeats. No repetition decreases were observed for ignored primes. Our results suggest a critical role for attention in achieving visual representations of objects that lead to both BOLD signal decreases and behavioral priming on repeated presentation.

BOLD cardiovascular magnetic resonance at 3.0 tesla in myocardial ischemia

Directory of Open Access Journals (Sweden)

Gebker Rolf

2010-09-01

Full Text Available Abstract Background The purpose of this study was to determine the ability of Blood Oxygen Level Dependent (BOLD cardiovascular magnetic resonance (CMR to detect stress-inducible myocardial ischemic reactions in the presence of angiographically significant coronary artery disease (CAD. Methods Forty-six patients (34 men; age 65 ± 9 years, with suspected or known coronary artery disease underwent CMR at 3Tesla prior to clinically indicated invasive coronary angiography. BOLD CMR was performed in 3 short axis slices of the heart at rest and during adenosine stress (140 μg/kg/min followed by late gadolinium enhancement (LGE imaging. In all 16 standard myocardial segments, T2* values were derived at rest and under adenosine stress. Quantitative coronary angiography served as the standard of reference and defined normal myocardial segments (i.e. all 16 segments in patients without any CAD, ischemic segments (i.e. supplied by a coronary artery with ≥50% luminal narrowing and non-ischemic segments (i.e. supplied by a non-significantly stenosed coronary artery in patients with significant CAD. Results Coronary angiography demonstrated significant CAD in 23 patients. BOLD CMR at rest revealed significantly lower T2* values for ischemic segments (26.7 ± 11.6 ms compared to normal (31.9 ± 11.9 ms; p Conclusions Rest and stress BOLD CMR at 3Tesla proved feasible and differentiated between ischemic, non-ischemic, and normal myocardial segments in a clinical patient population. BOLD CMR during vasodilator stress identified patients with significant CAD.

Evolution of boldness and life-history in response to selective harvesting

DEFF Research Database (Denmark)

Andersen, Ken Haste; Marty, Lise; Arlinghaus, Robert

2018-01-01

Whether intensive harvesting alters the behavioral repertoire of exploited fishes is currently unknown, but plausible. We extend a fish life-history model to account for boldness as a personality trait that affects foraging intensity, which affects energy intake and risk from predation and fishing...... gear. We systematically investigate life-history and behavioral trait evolution along the boldness–timidity axis in response to the full range of common selectivity and exploitation patterns in fisheries. In agreement with previous studies, we find that any type of harvesting selects for fast life...... histories and that merely elevated, yet unselective, fishing mortality favors boldness. We also find that timid-selective fishing (which can be expected in species targeted by active gear types) selects for increased boldness. By contrast, increased timidity is predicted when fishing targets bolder...

Searching for Conservation Laws in Brain Dynamics—BOLD Flux and Source Imaging

Directory of Open Access Journals (Sweden)

Henning U. Voss

2014-07-01

Full Text Available Blood-oxygen-level-dependent (BOLD imaging is the most important noninvasive tool to map human brain function. It relies on local blood-flow changes controlled by neurovascular coupling effects, usually in response to some cognitive or perceptual task. In this contribution we ask if the spatiotemporal dynamics of the BOLD signal can be modeled by a conservation law. In analogy to the description of physical laws, which often can be derived from some underlying conservation law, identification of conservation laws in the brain could lead to new models for the functional organization of the brain. Our model is independent of the nature of the conservation law, but we discuss possible hints and motivations for conservation laws. For example, globally limited blood supply and local competition between brain regions for blood might restrict the large scale BOLD signal in certain ways that could be observable. One proposed selective pressure for the evolution of such conservation laws is the closed volume of the skull limiting the expansion of brain tissue by increases in blood volume. These ideas are demonstrated on a mental motor imagery fMRI experiment, in which functional brain activation was mapped in a group of volunteers imagining themselves swimming. In order to search for local conservation laws during this complex cognitive process, we derived maps of quantities resulting from spatial interaction of the BOLD amplitudes. Specifically, we mapped fluxes and sources of the BOLD signal, terms that would appear in a description by a continuity equation. Whereas we cannot present final answers with the particular analysis of this particular experiment, some results seem to be non-trivial. For example, we found that during task the group BOLD flux covered more widespread regions than identified by conventional BOLD mapping and was always increasing during task. It is our hope that these results motivate more work towards the search for conservation

BOLD Granger causality reflects vascular anatomy.

Directory of Open Access Journals (Sweden)

J Taylor Webb

Full Text Available A number of studies have tried to exploit subtle phase differences in BOLD time series to resolve the order of sequential activation of brain regions, or more generally the ability of signal in one region to predict subsequent signal in another region. More recently, such lag-based measures have been applied to investigate directed functional connectivity, although this application has been controversial. We attempted to use large publicly available datasets (FCON 1000, ADHD 200, Human Connectome Project to determine whether consistent spatial patterns of Granger Causality are observed in typical fMRI data. For BOLD datasets from 1,240 typically developing subjects ages 7-40, we measured Granger causality between time series for every pair of 7,266 spherical ROIs covering the gray matter and 264 seed ROIs at hubs of the brain's functional network architecture. Granger causality estimates were strongly reproducible for connections in a test and replication sample (n=620 subjects for each group, as well as in data from a single subject scanned repeatedly, both during resting and passive video viewing. The same effect was even stronger in high temporal resolution fMRI data from the Human Connectome Project, and was observed independently in data collected during performance of 7 task paradigms. The spatial distribution of Granger causality reflected vascular anatomy with a progression from Granger causality sources, in Circle of Willis arterial inflow distributions, to sinks, near large venous vascular structures such as dural venous sinuses and at the periphery of the brain. Attempts to resolve BOLD phase differences with Granger causality should consider the possibility of reproducible vascular confounds, a problem that is independent of the known regional variability of the hemodynamic response.

Correlation between MEG and BOLD fMRI signals induced by visual flicker stimuli

Institute of Scientific and Technical Information of China (English)

Chu Renxin; Holroyd Tom; Duyn Jeff

2007-01-01

The goal of this work was to investigate how the MEG signal amplitude correlates with that of BOLD fMRI.To investigate the correlation between fMRI and macroscopic electrical activity, BOLD fMRI and MEG was performed on the same subjects (n =5). A visual flicker stimulus of varying temporal frequency was used to elicit neural responses in early visual areas. A strong similarity was observed in frequency tuning curves between both modalities.Although, averaged over subjects, the BOLD tuning curve was somewhat broader than MEG, both BOLD and MEG had maxima at a flicker frequency of 10 Hz. Also, we measured the first and second harmonic components as the stimuli frequency by MEG. In the low stimuli frequency (less than 6 Hz), the second harmonic has comparable amplitude with the first harmonic, which implies that neural frequency response is nonlinear and has more nonlinear components in low frequency than in high frequency.

Analysis of Neural-BOLD Coupling through Four Models of the Neural Metabolic Demand

Directory of Open Access Journals (Sweden)

Christopher W Tyler

2015-12-01

Full Text Available The coupling of the neuronal energetics to the blood-oxygen-level-dependent (BOLD response is still incompletely understood. To address this issue, we compared the fits of four plausible models of neurometabolic coupling dynamics to available data for simultaneous recordings of the local field potential (LFP and the local BOLD response recorded from monkey primary visual cortex over a wide range of stimulus durations. The four models of the metabolic demand driving the BOLD response were: direct coupling with the overall LFP; rectified coupling to the LFP; coupling with a slow adaptive component of the implied neural population response; and coupling with the non-adaptive intracellular input signal defined by the stimulus time course. Taking all stimulus durations into account, the results imply that the BOLD response is most closely coupled with metabolic demand derived from the intracellular input waveform, without significant influence from the adaptive transients and nonlinearities exhibited by the LFP waveform.

Development of visual cortical function in infant macaques: A BOLD fMRI study.

Directory of Open Access Journals (Sweden)

Tom J Van Grootel

Full Text Available Functional brain development is not well understood. In the visual system, neurophysiological studies in nonhuman primates show quite mature neuronal properties near birth although visual function is itself quite immature and continues to develop over many months or years after birth. Our goal was to assess the relative development of two main visual processing streams, dorsal and ventral, using BOLD fMRI in an attempt to understand the global mechanisms that support the maturation of visual behavior. Seven infant macaque monkeys (Macaca mulatta were repeatedly scanned, while anesthetized, over an age range of 102 to 1431 days. Large rotating checkerboard stimuli induced BOLD activation in visual cortices at early ages. Additionally we used static and dynamic Glass pattern stimuli to probe BOLD responses in primary visual cortex and two extrastriate areas: V4 and MT-V5. The resulting activations were analyzed with standard GLM and multivoxel pattern analysis (MVPA approaches. We analyzed three contrasts: Glass pattern present/absent, static/dynamic Glass pattern presentation, and structured/random Glass pattern form. For both GLM and MVPA approaches, robust coherent BOLD activation appeared relatively late in comparison to the maturation of known neuronal properties and the development of behavioral sensitivity to Glass patterns. Robust differential activity to Glass pattern present/absent and dynamic/static stimulus presentation appeared first in V1, followed by V4 and MT-V5 at older ages; there was no reliable distinction between the two extrastriate areas. A similar pattern of results was obtained with the two analysis methods, although MVPA analysis showed reliable differential responses emerging at later ages than GLM. Although BOLD responses to large visual stimuli are detectable, our results with more refined stimuli indicate that global BOLD activity changes as behavioral performance matures. This reflects an hierarchical development of

BOLD cardiovascular magnetic resonance at 3.0 tesla in myocardial ischemia.

OpenAIRE

Manka, R; Paetsch, I; Schnackenburg, B; Gebker, R; Fleck, E; Jahnke, C

2010-01-01

Abstract Background The purpose of this study was to determine the ability of Blood Oxygen Level Dependent (BOLD) cardiovascular magnetic resonance (CMR) to detect stress-inducible myocardial ischemic reactions in the presence of angiographically significant coronary artery disease (CAD). Methods Forty-six patients (34 men; age 65 ± 9 years,) with suspected or known coronary artery disease underwent CMR at 3Tesla prior to clinically indicated invasive coronary angiography. BOLD CMR was perfor...

Towards prognostic biomarkers from BOLD fluctuations to differentiate a first epileptic seizure from new-onset epilepsy.

Science.gov (United States)

Gupta, Lalit; Janssens, Rick; Vlooswijk, Mariëlle C G; Rouhl, Rob P W; de Louw, Anton; Aldenkamp, Albert P; Ulman, Shrutin; Besseling, René M H; Hofman, Paul A M; van Kranen-Mastenbroek, Vivianne H; Hilkman, Danny M; Jansen, Jacobus F A; Backes, Walter H

2017-03-01

The diagnosis of epilepsy cannot be reliably made prior to a patient's second seizure in most cases. Therefore, adequate diagnostic tools are needed to differentiate subjects with a first seizure from those with a seizure preceding the onset of epilepsy. The objective was to explore spontaneous blood oxygen level-dependent (BOLD) fluctuations in subjects with a first-ever seizure and patients with new-onset epilepsy (NOE), and to find characteristic biomarkers for seizure recurrence after the first seizure. We examined 17 first-seizure subjects, 19 patients with new-onset epilepsy (NOE), and 18 healthy controls. All subjects underwent clinical investigation and received electroencephalography and resting-state functional magnetic resonance imaging (MRI). The BOLD time series were analyzed in terms of regional homogeneity (ReHo) and fractional amplitude of low-frequency fluctuations (fALFFs). We found significantly stronger amplitudes (higher fALFFs) in patients with NOE relative to first-seizure subjects and healthy controls. The frequency range of 73-198 mHz (slow-3 subband) appeared most useful for discriminating patients with NOE from first-seizure subjects. The ReHo measure did not show any significant differences. The fALFF appears to be a noninvasive measure that characterizes spontaneous BOLD fluctuations and shows stronger amplitudes in the slow-3 subband of patients with NOE relative first-seizure subjects and healthy controls. A larger study population with follow-up is required to determine whether fALFF holds promise as a potential biomarker for identifying subjects at increased risk to develop epilepsy. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Research progress of BOLD-fMRI in minimal hepatic encephalopathy

International Nuclear Information System (INIS)

Zhou Zhiming; Zhao Jiannong

2013-01-01

The minimal hepatic encephalopathy is the early stage of hepatic encephalopathy. It has few apparent clinical symptoms and specific manifestations, and is difficult to diagnose. In the recent years, BOLD-fMRI has been used to study hepatic encephalopathy gradually. Through detection of the brain neuron activities in different states, it can not only locate the abnormal activity of brain functional areas, but also can find the changes of brain functional connectivity. BOLD- fMRI combining with other MR technologies can explore the pathology and pathogenesis of minimal hepatic encephalopathy from micro to macro and from structure to function. (authors)

Correlative BOLD MR imaging of stages of synovitis in a rabbit model of antigen-induced arthritis

International Nuclear Information System (INIS)

Doria, Andrea S.; Crawley, Adrian; Gahunia, Harpal; Rayner, Tammy; Tassos, Vivian; Zhong, Anguo; Moineddin, Rahim; Pritzker, Kenneth; Mendes, Maria; Jong, Roland; Salter, Robert B.

2012-01-01

Because of the ability of blood-oxygen-level-dependent (BOLD) MRI to assess blood oxygenation changes within the microvasculature, this technique holds potential for evaluating early perisynovial changes in inflammatory arthritis. To evaluate the feasibility of BOLD MRI to detect interval perisynovial changes in knees of rabbits with inflammatory arthritis. Rabbit knees were injected with albumin (n=9) or saline (n=6) intra-articularly, or were not injected (control knees, n=9). Except for two rabbits (albumin-injected, n=2 knees; saline-injected, n=2 knees) that unexpectedly died on days 7 and 21 of the experiment, respectively, all other animals were scanned with BOLD MRI on days 0, 1, 7, 14, 21 and 28 after induction of arthritis. T2*-weighted gradient-echo MRI was performed during alternate 30 s of normoxia/hyperoxia. BOLD MRI measurements were compared with clinical, laboratory and histological markers. Percentage of activated voxels was significantly greater in albumin-injected knees than in contralateral saline-injected knees (P=0.04). For albumin-injected knees (P < 0.05) and among different categories of knees (P=0.009), the percentage of activated BOLD voxels varied over time. A quadratic curve for on-and-off BOLD difference was delineated for albumin- and saline-injected knees over time (albumin-injected, P=0.047; saline-injected, P=0.009). A trend toward a significant difference in synovial histological scores between albumin-injected and saline-injected knees was noted only for acute scores (P=0.07). As a proof of concept, BOLD MRI can depict perisynovial changes during progression of experimental arthritis. (orig.)

Correlative BOLD MR imaging of stages of synovitis in a rabbit model of antigen-induced arthritis

Energy Technology Data Exchange (ETDEWEB)

Doria, Andrea S. [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); University of Toronto, Department of Medical Imaging, Toronto (Canada); Crawley, Adrian [University of Toronto, Department of Medical Imaging, Toronto (Canada); Toronto Western Hospital, Department of Medical Imaging, Toronto (Canada); Gahunia, Harpal; Rayner, Tammy; Tassos, Vivian; Zhong, Anguo [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Moineddin, Rahim [Family and Community Medicine, Department of Public Health, Toronto (Canada); Pritzker, Kenneth; Mendes, Maria; Jong, Roland [Mount Sinai Hospital, Department of Pathology and Laboratory Medicine, Toronto (Canada); Salter, Robert B. [Hospital for Sick Children, Department of Orthopedic Surgery, Toronto (Canada)

2012-01-15

Because of the ability of blood-oxygen-level-dependent (BOLD) MRI to assess blood oxygenation changes within the microvasculature, this technique holds potential for evaluating early perisynovial changes in inflammatory arthritis. To evaluate the feasibility of BOLD MRI to detect interval perisynovial changes in knees of rabbits with inflammatory arthritis. Rabbit knees were injected with albumin (n=9) or saline (n=6) intra-articularly, or were not injected (control knees, n=9). Except for two rabbits (albumin-injected, n=2 knees; saline-injected, n=2 knees) that unexpectedly died on days 7 and 21 of the experiment, respectively, all other animals were scanned with BOLD MRI on days 0, 1, 7, 14, 21 and 28 after induction of arthritis. T2*-weighted gradient-echo MRI was performed during alternate 30 s of normoxia/hyperoxia. BOLD MRI measurements were compared with clinical, laboratory and histological markers. Percentage of activated voxels was significantly greater in albumin-injected knees than in contralateral saline-injected knees (P=0.04). For albumin-injected knees (P < 0.05) and among different categories of knees (P=0.009), the percentage of activated BOLD voxels varied over time. A quadratic curve for on-and-off BOLD difference was delineated for albumin- and saline-injected knees over time (albumin-injected, P=0.047; saline-injected, P=0.009). A trend toward a significant difference in synovial histological scores between albumin-injected and saline-injected knees was noted only for acute scores (P=0.07). As a proof of concept, BOLD MRI can depict perisynovial changes during progression of experimental arthritis. (orig.)

Differences in aggression, activity and boldness between native and introduced populations of an invasive crayfish

Science.gov (United States)

Pintor, L.M.; Sih, A.; Bauer, M.L.

2008-01-01

Aggressiveness, along with foraging voracity and boldness, are key behavioral mechanisms underlying the competitive displacement and invasion success of exotic species. However, do aggressiveness, voracity and boldness of the invader depend on the presence of an ecologically similar native competitor in the invaded community? We conducted four behavioral assays to compare aggression, foraging voracity, threat response and boldness to forage under predation risk of multiple populations of exotic signal crayfish Pacifastacus leniusculus across its native and invaded range with and without a native congener, the Shasta crayfish P. fortis. We predicted that signal crayfish from the invaded range and sympatric with a native congener (IRS) should be more aggressive to outcompete a close competitor than populations from the native range (NR) or invaded range and allopatric to a native congener (IRA). Furthermore, we predicted that IRS populations of signal crayfish should be more voracious, but less bold to forage under predation risk since native predators and prey likely possess appropriate behavioral responses to the invader. Contrary to our predictions, results indicated that IRA signal crayfish were more aggressive towards conspecifics and more voracious and active foragers, yet also bolder to forage under predation risk in comparison to NR and IRS populations, which did not differ in behavior. Higher aggression/voracity/ boldness was positively correlated with prey consumption rates, and hence potential impacts on prey. We suggest that the positive correlations between aggression/voracity/boldness are the result of an overall aggression syndrome. Results of stream surveys indicated that IRA streams have significantly lower prey biomass than in IRS streams, which may drive invading signal crayfish to be more aggressive/voracious/bold to acquire resources to establish a population. ?? 2008 The Authors.

Right anterior cerebellum BOLD responses reflect age related changes in Simon task sequential effects.

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Aisenberg, D; Sapir, A; Close, A; Henik, A; d'Avossa, G

2018-01-31

Participants are slower to report a feature, such as color, when the target appears on the side opposite the instructed response, than when the target appears on the same side. This finding suggests that target location, even when task-irrelevant, interferes with response selection. This effect is magnified in older adults. Lengthening the inter-trial interval, however, suffices to normalize the congruency effect in older adults, by re-establishing young-like sequential effects (Aisenberg et al., 2014). We examined the neurological correlates of age related changes by comparing BOLD signals in young and old participants performing a visual version of the Simon task. Participants reported the color of a peripheral target, by a left or right-hand keypress. Generally, BOLD responses were greater following incongruent than congruent targets. Also, they were delayed and of smaller amplitude in old than young participants. BOLD responses in visual and motor regions were also affected by the congruency of the previous target, suggesting that sequential effects may reflect remapping of stimulus location onto the hand used to make a response. Crucially, young participants showed larger BOLD responses in right anterior cerebellum to incongruent targets, when the previous target was congruent, but smaller BOLD responses to incongruent targets when the previous target was incongruent. Old participants, however, showed larger BOLD responses to congruent than incongruent targets, irrespective of the previous target congruency. We conclude that aging may interfere with the trial by trial updating of the mapping between the task-irrelevant target location and response, which takes place during the inter-trial interval in the cerebellum and underlays sequential effects in a Simon task. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantifying the microvascular origin of BOLD-fMRI from first principles with two-photon microscopy and an oxygen-sensitive nanoprobe.

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Gagnon, Louis; Sakadžić, Sava; Lesage, Frédéric; Musacchia, Joseph J; Lefebvre, Joël; Fang, Qianqian; Yücel, Meryem A; Evans, Karleyton C; Mandeville, Emiri T; Cohen-Adad, Jülien; Polimeni, Jonathan R; Yaseen, Mohammad A; Lo, Eng H; Greve, Douglas N; Buxton, Richard B; Dale, Anders M; Devor, Anna; Boas, David A

2015-02-25

The blood oxygenation level-dependent (BOLD) contrast is widely used in functional magnetic resonance imaging (fMRI) studies aimed at investigating neuronal activity. However, the BOLD signal reflects changes in blood volume and oxygenation rather than neuronal activity per se. Therefore, understanding the transformation of microscopic vascular behavior into macroscopic BOLD signals is at the foundation of physiologically informed noninvasive neuroimaging. Here, we use oxygen-sensitive two-photon microscopy to measure the BOLD-relevant microvascular physiology occurring within a typical rodent fMRI voxel and predict the BOLD signal from first principles using those measurements. The predictive power of the approach is illustrated by quantifying variations in the BOLD signal induced by the morphological folding of the human cortex. This framework is then used to quantify the contribution of individual vascular compartments and other factors to the BOLD signal for different magnet strengths and pulse sequences. Copyright © 2015 the authors 0270-6474/15/353663-13$15.00/0.

Implications of oxidative stress in the brain plasticity originated by fasting: a BOLD-fMRI study.

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Belaïch, Rachida; Boujraf, Saïd; Benzagmout, Mohammed; Magoul, Rabia; Maaroufi, Mustapha; Tizniti, Siham

2017-11-01

The goal of this study was assessing the intermittent fasting effect on brain plasticity and oxidative stress (OS) using blood-oxygenation-level dependent (BOLD)-functional magnetic resonance image (fMRI) approach. Evidences of physiological and molecular phenomena involved in this process are discussed and compared to reported literature. Six fully healthy male non-smokers volunteered in this study. All volunteers were right handed, and have an equilibrated, consistent and healthy daily nutritional habit, and a healthy lifestyle. Participants were allowed consuming food during evening and night time while fasting with self-prohibiting food and liquids during 14 hours/day from sunrise to sunset. All participants underwent identical brain BOLD-fMRI protocol. The images were acquired in the Department of Radiology and Clinical Imaging of the University Hospital of Fez, Fez, Morocco. The anatomical brain and BOLD-fMRIs were acquired using a 1.5-Tesla scanner (Signa, General Electric, Milwaukee, United States). BOLD-fMRI image acquisition was done using single-shot gradient echo echo-planer imaging sequence. BOLD-fMRI paradigm consisted of the motor task where volunteers were asked to perform finger taping of the right hand. Two BOLD-fMRI scan sessions were performed, the first one between the 5th and 10th days preceding the start of fasting and the second between days 25th and 28th of the fasting month. All sessions were performed between 3:30 PM and 5:30 PM. Although individual maps were originated from different individual participants, they cover the same anatomic area in each case. Image processing and statistical analysis were conducted with Statistical Parameter Mapping version 8 (2008, Welcome Department of Cognitive Neurology, London UK). The maximal BOLD signal changes were calculated for each subject in the motor area M1; Activation maps were calculated and overlaid on the anatomical images. Group analysis of the data was performed, and the average volume

PARTICLE FILTERING WITH SEQUENTIAL PARAMETER LEARNING FOR NONLINEAR BOLD fMRI SIGNALS.

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Xia, Jing; Wang, Michelle Yongmei

Analyzing the blood oxygenation level dependent (BOLD) effect in the functional magnetic resonance imaging (fMRI) is typically based on recent ground-breaking time series analysis techniques. This work represents a significant improvement over existing approaches to system identification using nonlinear hemodynamic models. It is important for three reasons. First, instead of using linearized approximations of the dynamics, we present a nonlinear filtering based on the sequential Monte Carlo method to capture the inherent nonlinearities in the physiological system. Second, we simultaneously estimate the hidden physiological states and the system parameters through particle filtering with sequential parameter learning to fully take advantage of the dynamic information of the BOLD signals. Third, during the unknown static parameter learning, we employ the low-dimensional sufficient statistics for efficiency and avoiding potential degeneration of the parameters. The performance of the proposed method is validated using both the simulated data and real BOLD fMRI data.

Correlations of noninvasive BOLD and TOLD MRI with pO2 and relevance to tumor radiation response.

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Hallac, Rami R; Zhou, Heling; Pidikiti, Rajesh; Song, Kwang; Stojadinovic, Strahinja; Zhao, Dawen; Solberg, Timothy; Peschke, Peter; Mason, Ralph P

2014-05-01

To examine the potential use of blood oxygenation level dependent (BOLD) and tissue oxygenation level dependent (TOLD) contrast MRI to assess tumor oxygenation and predict radiation response. BOLD and TOLD MRI were performed on Dunning R3327-AT1 rat prostate tumors during hyperoxic gas breathing challenge at 4.7 T. Animals were divided into two groups. In Group 1 (n = 9), subsequent (19) F MRI based on spin lattice relaxation of hexafluorobenzene reporter molecule provided quantitative oximetry for comparison. For Group 2 rats (n = 13) growth delay following a single dose of 30 Gy was compared with preirradiation BOLD and TOLD assessments. Oxygen (100%O2 ) and carbogen (95%O2 /5%CO2 ) challenge elicited similar BOLD, TOLD and pO2 responses. Strong correlations were observed between BOLD or R2* response and quantitative (19) F pO2 measurements. TOLD response showed a general trend with weaker correlation. Irradiation caused a significant tumor growth delay and tumors with larger changes in TOLD and R1 values upon oxygen breathing exhibited significantly increased tumor growth delay. These results provide further insight into the relationships between oxygen sensitive (BOLD/TOLD) MRI and tumor pO2 . Moreover, a larger increase in R1 response to hyperoxic gas challenge coincided with greater tumor growth delay following irradiation. Copyright © 2013 Wiley Periodicals, Inc.

Gamma rays induced bold seeded high yielding mutant in chickpea

International Nuclear Information System (INIS)

Wani, A.A.; Anis, M.

2001-01-01

In pulses especially in chickpea (Cicer arietinum L.), genetic variability has been exhausted due to natural selection and hence conventional breeding methods are not very fruitful. Mutation techniques are the best methods to enlarge the genetically conditioned variability of a species within a short time and have played a significant role in the development of many crop varieties. Investigations on the effects of ionizing radiations and chemical mutagens in induction of macro-mutations have received much attention owing to their utmost importance in plant breeding. The present study reports a bold seeded mutant in chickpea, the most dominating pulse crop on the Indian subcontinent. Fresh seeds of chickpea variety 'Pusa-212' were procured from IARI, New Delhi and treated with different doses/concentrations of gamma rays ( 60 Co source at NBRI, Lucknow) and ethyl methanesulphonate (EMS), individually as well as in combination, to raise the M1 generation. Seeds of M 1 plants were sown to raise M2 plant progenies. A bold seeded mutant was isolated from 400 Gy gamma ray treatments. The mutant was confirmed as true bred, all the mutant seeds gave rise to morphologically similar plants in M 3 , which were quite distinct from the control. The bold seeded mutant showed 'gigas' characteristics and vigorous growth. The plant remained initially straight but later on attained a trailing habit due to heavy secondary branching. The leaves, petioles, flowers, pods and seeds were almost double that of the parent variety, in size. The flowering occurred 10 days later than the parent and maturity was also delayed accordingly. Observations were recorded on various quantitative traits. Plant height and number of primary branches showed a significant improvement over the parent. It is interesting to note that the number of pods and number of seeds per pod significantly decreased. However, the hundred seed weight (31.73±0.59g) in the mutant plants was more than double in the parent

Electrophysiological correlates of the BOLD signal for EEG-informed fMRI

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Murta, Teresa; Leite, Marco; Carmichael, David W; Figueiredo, Patrícia; Lemieux, Louis

2015-01-01

Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) are important tools in cognitive and clinical neuroscience. Combined EEG–fMRI has been shown to help to characterise brain networks involved in epileptic activity, as well as in different sensory, motor and cognitive functions. A good understanding of the electrophysiological correlates of the blood oxygen level-dependent (BOLD) signal is necessary to interpret fMRI maps, particularly when obtained in combination with EEG. We review the current understanding of electrophysiological–haemodynamic correlates, during different types of brain activity. We start by describing the basic mechanisms underlying EEG and BOLD signals and proceed by reviewing EEG-informed fMRI studies using fMRI to map specific EEG phenomena over the entire brain (EEG–fMRI mapping), or exploring a range of EEG-derived quantities to determine which best explain colocalised BOLD fluctuations (local EEG–fMRI coupling). While reviewing studies of different forms of brain activity (epileptic and nonepileptic spontaneous activity; cognitive, sensory and motor functions), a significant attention is given to epilepsy because the investigation of its haemodynamic correlates is the most common application of EEG-informed fMRI. Our review is focused on EEG-informed fMRI, an asymmetric approach of data integration. We give special attention to the invasiveness of electrophysiological measurements and the simultaneity of multimodal acquisitions because these methodological aspects determine the nature of the conclusions that can be drawn from EEG-informed fMRI studies. We emphasise the advantages of, and need for, simultaneous intracranial EEG–fMRI studies in humans, which recently became available and hold great potential to improve our understanding of the electrophysiological correlates of BOLD fluctuations. PMID:25277370

Task performance changes the amplitude and timing of the BOLD signal

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Akhrif Atae

2017-12-01

Full Text Available Translational studies comparing imaging data of animals and humans have gained increasing scientific interests. With this upcoming translational approach, however, identifying harmonized statistical analysis as well as shared data acquisition protocols and/or combined statistical approaches is necessary. Following this idea, we applied Bayesian Adaptive Regression Splines (BARS, which have until now mainly been used to model neural responses of electrophysiological recordings from rodent data, on human hemodynamic responses as measured via fMRI. Forty-seven healthy subjects were investigated while performing the Attention Network Task in the MRI scanner. Fluctuations in the amplitude and timing of the BOLD response were determined and validated externally with brain activation using GLM and also ecologically with the influence of task performance (i.e. good vs. bad performers. In terms of brain activation, bad performers presented reduced activation bilaterally in the parietal lobules, right prefrontal cortex (PFC and striatum. This was accompanied by an enhanced left PFC recruitment. With regard to the amplitude of the BOLD-signal, bad performers showed enhanced values in the left PFC. In addition, in the regions of reduced activation such as the parietal and striatal regions, the temporal dynamics were higher in bad performers. Based on the relation between BOLD response and neural firing with the amplitude of the BOLD signal reflecting gamma power and timing dynamics beta power, we argue that in bad performers, an enhanced left PFC recruitment hints towards an enhanced functioning of gamma-band activity in a compensatory manner. This was accompanied by reduced parieto-striatal activity, associated with increased and potentially conflicting beta-band activity.

Unemployment in chronic airflow obstruction around the world: results from the BOLD study.

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Grønseth, Rune; Erdal, Marta; Tan, Wan C; Obaseki, Daniel O; Amaral, Andre F S; Gislason, Thorarinn; Juvekar, Sanjay K; Koul, Parvaiz A; Studnicka, Michael; Salvi, Sundeep; Burney, Peter; Buist, A Sonia; Vollmer, William M; Johannessen, Ane

2017-09-01

We aimed to examine associations between chronic airflow obstruction (CAO) and unemployment across the world.Cross-sectional data from 26 sites in the Burden of Obstructive Lung Disease (BOLD) study were used to analyse effects of CAO on unemployment. Odds ratios for unemployment in subjects aged 40-65 years were estimated using a multilevel mixed-effects generalised linear model with study site as random effect. Site-by-site heterogeneity was assessed using individual participant data meta-analyses.Out of 18 710 participants, 11.3% had CAO. The ratio of unemployed subjects with CAO divided by subjects without CAO showed large site discrepancies, although these were no longer significant after adjusting for age, sex, smoking and education. The site-adjusted odds ratio (95% CI) for unemployment was 1.79 (1.41-2.27) for CAO cases, decreasing to 1.43 (1.14-1.79) after adjusting for sociodemographic factors, comorbidities and forced vital capacity. Of other covariates that were associated with unemployment, age and education were important risk factors in high-income sites (4.02 (3.53-4.57) and 3.86 (2.80-5.30), respectively), while female sex was important in low- to middle-income sites (3.23 (2.66-3.91)).In the global BOLD study, CAO was associated with increased levels of unemployment, even after adjusting for sociodemographic factors, comorbidities and lung function. Copyright ©ERS 2017.

Time courses of MRI BOLD signals in prolonged visual stimulation. Comparison between colors and orders

International Nuclear Information System (INIS)

Kashikura, Kenichi; Fujita, Hideaki; Kershaw, J.B.; Matsuura, Tetsuya; Seki, Chie; Kashikura, Akemi; Ardekani, B.A.; Kanno, Iwao

1998-01-01

We investigated: the BOLD signal response during 270 second photic stimulation using an EPI pulse sequence; the BOLD signal response for two different color checkerboards; and the BOLD signal response during six consecutive stimulation series. Ten healthy human subjects (age 25±5.5 years) were studied with a 1.5 T MRI system (Siemens Vision, Erlangen, Germany). Black and white (BW) and red and white (RW) checkerboards alternating at 8 Hz were applied in turns for a total series of six. Stimulation timing was: 30 sec. off, 15 sec. on, 15 sec. off, 270 sec. on, 15 sec. off, 15 sec. on, 15 sec. off. Acquired data were analyzed according to color and/or order: color (without considering the order); color and order (1st BW vs. 1st RW, 2nd BW vs. 2nd RW, 3rd BW vs. 3rd RW); and order (without considering the color). A t-test (p<0.001) was used for obtaining the activated areas, and simple regression and two-way repeated-measures ANOVA were used for testing the statistical significance of the BOLD response. Results were: the BOLD signal responses during sustained photic stimulation maintained a constant level for the full duration and all series, suggesting stable levels of oxygen extraction and metabolism during cortical activation; the BOLD signal responses in two colors showed no significant difference in time response, suggesting that the neuronal populations perceiving black and red give a similar time response; and the effect of habituation or fatigue as observed by a signal decrease was not obtained, although the S.D. for each subject greatly increased with time and might be an indicator for evaluation fatigue or attention. (author)

Spatial attention related SEP amplitude modulations covary with BOLD signal in S1--a simultaneous EEG--fMRI study.

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Schubert, Ruth; Ritter, Petra; Wüstenberg, Torsten; Preuschhof, Claudia; Curio, Gabriel; Sommer, Werner; Villringer, Arno

2008-11-01

Recent studies investigating the influence of spatial-selective attention on primary somatosensory processing have produced inconsistent results. The aim of this study was to explore the influence of tactile spatial-selective attention on spatiotemporal aspects of evoked neuronal activity in the primary somatosensory cortex (S1). We employed simultaneous electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) in 14 right-handed subjects during bilateral index finger Braille stimulation to investigate the relationship between attentional effects on somatosensory evoked potential (SEP) components and the blood oxygenation level-dependent (BOLD) signal. The 1st reliable EEG response following left tactile stimulation (P50) was significantly enhanced by spatial-selective attention, which has not been reported before. FMRI analysis revealed increased activity in contralateral S1. Remarkably, the effect of attention on the P50 component as well as long-latency SEP components starting at 190 ms for left stimuli correlated with attentional effects on the BOLD signal in contralateral S1. The implications are 2-fold: First, the correlation between early and long-latency SEP components and the BOLD effect suggest that spatial-selective attention enhances processing in S1 at 2 time points: During an early passage of the signal and during a later passage, probably via re-entrant feedback from higher cortical areas. Second, attentional modulations of the fast electrophysiological signals and the slow hemodynamic response are linearly related in S1.

Pharmacological modulation of the BOLD response: a study of acetazolamide and glyceryl trinitrate in humans

DEFF Research Database (Denmark)

Asghar, Mohammed Sohail; Hansen, Adam E; Pedersen, Simon

2011-01-01

To examine the effect of acetazolamide, known to increase cerebral blood flow (CBF) and glyceryl trinitrate (GTN), known to increase cerebral blood volume (CBV) on the blood oxygenation level-dependent (BOLD) response in humans using 3 T magnetic resonance imaging (MRI), and to evaluate how...... pharmacological agents may modulate cerebral hemodynamic and thereby possibly the BOLD signal....

A comparison of measures of boldness and their relationships to survival in young fish.

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James R White

Full Text Available Boldness is the propensity of an animal to engage in risky behavior. Many variations of novel-object or novel-environment tests have been used to quantify the boldness of animals, although the relationship between test outcomes has rarely been investigated. Furthermore, the relationship of outcomes to any ecological aspect of fitness is generally assumed, rather than measured directly. Our study is the first to compare how the outcomes of the same test of boldness differ among observers and how different tests of boldness relate to the survival of individuals in the field. Newly-metamorphosed lemon damselfish, Pomacentrus moluccensis, were placed onto replicate patches of natural habitat. Individual behavior was quantified using four tests (composed of a total of 12 different measures of behavior: latency to enter a novel environment, activity in a novel environment, and reactions to threatening and benign novel objects. After behavior was quantified, survival was monitored for two days during which time fish were exposed to natural predators. Variation among observers was low for most of the 12 measures, except distance moved and the threat test (reaction to probe thrust, which displayed unacceptable amounts of inter-observer variation. Overall, the results of the behavioral tests suggested that novel environment and novel object tests quantified similar behaviors, yet these behavioral measures were not interchangeable. Multiple measures of behavior within the context of novel environment or object tests were the most robust way to assess boldness and these measures have a complex relationship with survivorship of young fish in the field. Body size and distance ventured from shelter were the only variables that had a direct and positive relationship with survival.

Negative BOLD signal changes in ipsilateral primary somatosensory cortex are associated with perfusion decreases and behavioral evidence for functional inhibition

DEFF Research Database (Denmark)

Schäfer, Katharina; Blankenburg, Felix; Kupers, Ron

2012-01-01

that the negative BOLD signal is associated with functional inhibition. Electrical stimulation of the median nerve at 7Hz evoked robust negative BOLD signals in the primary somatosensory cortex (SI) ipsilateral to stimulation, and positive BOLD signals in contralateral SI. The negative BOLD signal in ipsilateral SI......) at the ipsilateral finger during concomitant stimulation of the contralateral median nerve increased significantly, suggesting augmented functional inhibition. Since the CPT in the ipsilateral hallux did not significantly change in response to median nerve stimulation, it is more likely that the CPT......-increase for the finger is due to functional inhibition (Kastrup et al., 2008) than to changes in selective attention. In conclusion, our data provide evidence that stimulus-induced reductions in relative rCBF may underlie the negative BOLD signal, which in turn may reflect increments in functional inhibition....

Blood Flow and Brain Function: Investigations of neurovascular coupling using BOLD fMRI at 7 tesla

NARCIS (Netherlands)

Siero, J.C.W.

2013-01-01

The advent of ultra high field (7 tesla) MRI systems has opened the possibility to probe biological processes of the human body in great detail. Especially for studying brain function using BOLD fMRI there is a large benefit from the increased magnetic field strength. BOLD fMRI is the working horse

Distinction between Neural and Vascular BOLD Oscillations and Intertwined Heart Rate Oscillations at 0.1 Hz in the Resting State and during Movement.

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Gert Pfurtscheller

Full Text Available In the resting state, blood oxygen level-dependent (BOLD oscillations with a frequency of about 0.1 Hz are conspicuous. Whether their origin is neural or vascular is not yet fully understood. Furthermore, it is not clear whether these BOLD oscillations interact with slow oscillations in heart rate (HR. To address these two questions, we estimated phase-locking (PL values between precentral gyrus (PCG and insula in 25 scanner-naïve individuals during rest and stimulus-paced finger movements in both hemispheres. PL was quantified in terms of time delay and duration in the frequency band 0.07 to 0.13 Hz. Results revealed both positive and negative time delays. Positive time delays characterize neural BOLD oscillations leading in the PCG, whereas negative time delays represent vascular BOLD oscillations leading in the insula. About 50% of the participants revealed positive time delays distinctive for neural BOLD oscillations, either with short or long unilateral or bilateral phase-locking episodes. An expected preponderance of neural BOLD oscillations was found in the left hemisphere during right-handed movement and unexpectedly in the right hemisphere during rest. Only neural BOLD oscillations were significantly associated with heart rate variability (HRV in the 0.1-Hz range in the first resting state. It is well known that participating in magnetic resonance imaging (MRI studies may be frightening and cause anxiety. In this respect it is important to note that the most significant hemispheric asymmetry (p<0.002 with a right-sided dominance of neural BOLD and a left-sided dominance of vascular BOLD oscillations was found in the first resting session in the scanner-naïve individuals. Whether the enhanced left-sided perfusion (dominance of vascular BOLD or the right-sided dominance of neural BOLD is related to the increased level of anxiety, attention or stress needs further research.

BOLD Imaging in Awake Wild-Type and Mu-Opioid Receptor Knock-Out Mice Reveals On-Target Activation Maps in Response to Oxycodone

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Kelsey Moore

2016-11-01

Full Text Available Blood oxygen level dependent (BOLD imaging in awake mice was used to identify differences in brain activity between wild-type, and Mu (µ opioid receptor knock-outs (MuKO in response to oxycodone (OXY. Using a segmented, annotated MRI mouse atlas and computational analysis, patterns of integrated positive and negative BOLD activity were identified across 122 brain areas. The pattern of positive BOLD showed enhanced activation across the brain in WT mice within 15 min of intraperitoneal administration of 2.5 mg of OXY. BOLD activation was detected in 72 regions out of 122, and was most prominent in areas of high µ opioid receptor density (thalamus, ventral tegmental area, substantia nigra, caudate putamen, basal amygdala and hypothalamus, and focus on pain circuits indicated strong activation in major pain processing centers (central amygdala, solitary tract, parabrachial area, insular cortex, gigantocellularis area, ventral thalamus primary sensory cortex and prelimbic cortex. Importantly, the OXY-induced positive BOLD was eliminated in MuKO mice in most regions, with few exceptions (some cerebellar nuclei, CA3 of the hippocampus, medial amygdala and preoptic areas. This result indicates that most effects of OXY on positive BOLD are mediated by the µ opioid receptor (on-target effects. OXY also caused an increase in negative BOLD in WT mice in few regions (16 out of 122 and, unlike the positive BOLD response the negative BOLD was only partially eliminated in the MuKO mice (cerebellum, and in some case intensified (hippocampus. Negative BOLD analysis therefore shows activation and deactivation events in the absence of the µ receptor for some areas where receptor expression is normally extremely low or absent (off-target effects. Together, our approach permits establishing opioid-induced BOLD activation maps in awake mice. In addition, comparison of WT and MuKO mutant mice reveals both on-target and off-target activation events, and set an OXY

Mapping transient hyperventilation induced alterations with estimates of the multi-scale dynamics of BOLD signal.

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Vesa J Kiviniemi

2009-07-01

Full Text Available Temporal blood oxygen level dependent (BOLD contrast signals in functional MRI during rest may be characterized by power spectral distribution (PSD trends of the form 1/f α. Trends with 1/f characteristics comprise fractal properties with repeating oscillation patterns in multiple time scales. Estimates of the fractal properties enable the quantification of phenomena that may otherwise be difficult to measure, such as transient, non-linear changes. In this study it was hypothesized that the fractal metrics of 1/f BOLD signal trends can map changes related to dynamic, multi-scale alterations in cerebral blood flow (CBF after a transient hyperventilation challenge. Twenty-three normal adults were imaged in a resting-state before and after hyperventilation. Different variables (1/f trend constant α, fractal dimension Df, and, Hurst exponent H characterizing the trends were measured from BOLD signals. The results show that fractal metrics of the BOLD signal follow the fractional Gaussian noise model, even during the dynamic CBF change that follows hyperventilation. The most dominant effect on the fractal metrics was detected in grey matter, in line with previous hyperventilation vaso-reactivity studies. The α was able to differentiate also blood vessels from grey matter changes. Df was most sensitive to grey matter. H correlated with default mode network areas before hyperventilation but this pattern vanished after hyperventilation due to a global increase in H. In the future, resting-state fMRI combined with fractal metrics of the BOLD signal may be used for analyzing multi-scale alterations of cerebral blood flow.

Mapping Transient Hyperventilation Induced Alterations with Estimates of the Multi-Scale Dynamics of BOLD Signal.

Science.gov (United States)

Kiviniemi, Vesa; Remes, Jukka; Starck, Tuomo; Nikkinen, Juha; Haapea, Marianne; Silven, Olli; Tervonen, Osmo

2009-01-01

Temporal blood oxygen level dependent (BOLD) contrast signals in functional MRI during rest may be characterized by power spectral distribution (PSD) trends of the form 1/f(alpha). Trends with 1/f characteristics comprise fractal properties with repeating oscillation patterns in multiple time scales. Estimates of the fractal properties enable the quantification of phenomena that may otherwise be difficult to measure, such as transient, non-linear changes. In this study it was hypothesized that the fractal metrics of 1/f BOLD signal trends can map changes related to dynamic, multi-scale alterations in cerebral blood flow (CBF) after a transient hyperventilation challenge. Twenty-three normal adults were imaged in a resting-state before and after hyperventilation. Different variables (1/f trend constant alpha, fractal dimension D(f), and, Hurst exponent H) characterizing the trends were measured from BOLD signals. The results show that fractal metrics of the BOLD signal follow the fractional Gaussian noise model, even during the dynamic CBF change that follows hyperventilation. The most dominant effect on the fractal metrics was detected in grey matter, in line with previous hyperventilation vaso-reactivity studies. The alpha was able to differentiate also blood vessels from grey matter changes. D(f) was most sensitive to grey matter. H correlated with default mode network areas before hyperventilation but this pattern vanished after hyperventilation due to a global increase in H. In the future, resting-state fMRI combined with fractal metrics of the BOLD signal may be used for analyzing multi-scale alterations of cerebral blood flow.

Cortical Network Models of Firing Rates in the Resting and Active States Predict BOLD Responses.

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Maxwell R Bennett

Full Text Available Measurements of blood oxygenation level dependent (BOLD signals have produced some surprising observations. One is that their amplitude is proportional to the entire activity in a region of interest and not just the fluctuations in this activity. Another is that during sleep and anesthesia the average BOLD correlations between regions of interest decline as the activity declines. Mechanistic explanations of these phenomena are described here using a cortical network model consisting of modules with excitatory and inhibitory neurons, taken as regions of cortical interest, each receiving excitatory inputs from outside the network, taken as subcortical driving inputs in addition to extrinsic (intermodular connections, such as provided by associational fibers. The model shows that the standard deviation of the firing rate is proportional to the mean frequency of the firing when the extrinsic connections are decreased, so that the mean BOLD signal is proportional to both as is observed experimentally. The model also shows that if these extrinsic connections are decreased or the frequency of firing reaching the network from the subcortical driving inputs is decreased, or both decline, there is a decrease in the mean firing rate in the modules accompanied by decreases in the mean BOLD correlations between the modules, consistent with the observed changes during NREM sleep and under anesthesia. Finally, the model explains why a transient increase in the BOLD signal in a cortical area, due to a transient subcortical input, gives rises to responses throughout the cortex as observed, with these responses mediated by the extrinsic (intermodular connections.

Socially bold personality in the real communication and Internet communication: the analysis of representations of people of the different age

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Pogodina A. V.

2017-03-01

Full Text Available The article is concerned with the results of the study, subject of which is the submis- sion of the respondents of the different age groups about the social and bold personality. Required property of the respondents was the presence in the Internet environment and participation in various social networks. They assessed social and bold personal- ity in such contexts of communication, as real communication and Internet communication. Analyses were undertaken to determine the structural and content features of emotional and semantic representations of the phenomenon of the social and bold personality, depending on the context of communication, but also the detection of age-sensitive representations of the young respondents (19—35 years, middle-aged respondents (36-55 years and older respondents (from 56 to 70 years. The concept of the “social and bold personality in real communion” is shown to have a high semantic relevance, strongly marked positive emotional coloration and a similar factor structure for respondents of all age groups. The concept of the “social and bold personality in online communication” with a high semantic significance in the perception of the young respondents moves into a zone of moderate and semantic importance in representations of the middle-aged and older respondents. In representations of the respondents of all age groups, the attractiveness of the "social and bold personality in Internet communication" is less than in comparison with the "social and bold personality in the real communication". The age-specific of the social representations about social and bold personality in the real and virtual communication has been analysed in detail.

Somatosensory BOLD fMRI reveals close link between salient blood pressure changes and the murine neuromatrix.

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Reimann, Henning Matthias; Todiras, Mihail; Hodge, Russ; Huelnhagen, Till; Millward, Jason Michael; Turner, Robert; Seeliger, Erdmann; Bader, Michael; Pohlmann, Andreas; Niendorf, Thoralf

2018-05-15

The neuromatrix, or "pain matrix", is a network of cortical brain areas which is activated by noxious as well as salient somatosensory stimulation. This has been studied in mice and humans using blood oxygenation level-dependent (BOLD) fMRI. Here we demonstrate that BOLD effects observed in the murine neuromatrix in response to salient somatosensory stimuli are prone to reflect mean arterial blood pressure (MABP) changes, rather than neural activity. We show that a standard electrostimulus typically used in murine somatosensory fMRI can induce substantial elevations in MABP. Equivalent drug-induced MABP changes - without somatosensory stimulation - evoked BOLD patterns in the neuromatrix strikingly similar to those evoked by electrostimulation. This constitutes a serious caveat for murine fMRI. The regional specificity of these BOLD patterns can be attributed to the co-localization of the neuromatrix with large draining veins. Based on these findings we propose a cardiovascular support mechanism whereby abrupt elevations in MABP provide additional energy supply to the neuromatrix and other essential brain areas in fight-or-flight situations. Copyright © 2018 Elsevier Inc. All rights reserved.

Detection of Acute Tubular Necrosis Using Blood Oxygenation Level-Dependent (BOLD MRI

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Frederic Bauer

2017-12-01

Full Text Available Background/Aims: To date, there is no imaging technique to assess tubular function in vivo. Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI measures tissue oxygenation based on the transverse relaxation rate (R2*. The present study investigates whether BOLD MRI can assess tubular function using a tubule-specific pharmacological maneuver. Methods: Cross sectional study with 28 participants including 9 subjects with ATN-induced acute kidney injury (AKI, 9 healthy controls, and 10 subjects with nephron sparing tumor resection (NSS with clamping of the renal artery serving as a model of ischemia/reperfusion (I/R-induced subclinical ATN (median clamping time 15 min, no significant decrease of eGFR, p=0.14. BOLD MRI was performed before and 5, 7, and 10 min after intravenous administration of 40 mg furosemide. Results: Urinary neutrophil gelatinase-associated lipocalin was significantly higher in ATN-induced AKI and NSS subjects than in healthy controls (p=0.03 and p=0.01, respectively. Before administration of furosemide, absolute medullary R2*, cortical R2*, and medullary/cortical R2* ratio did not significantly differ between ATN-induced AKI vs. healthy controls and between NSS-I/R vs. contralateral healthy kidneys (p>0.05 each. Furosemide led to a significant decrease in the medullary and cortical R2* of healthy subjects and NSS contralateral kidneys (p<0.05 each, whereas there was no significant change of R2* in ATN-induced AKI and the NSS-I/R kidneys (p>0.05 each. Conclusion: BOLD-MRI is able to detect even mild tubular injury but necessitates a tubule-specific pharmacological maneuver, e.g. blocking the Na+-K+-2Cl- transporter by furosemide.

Correlation of BOLD Signal with Linear and Nonlinear Patterns of EEG in Resting State EEG-Informed fMRI

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Galina V. Portnova

2018-01-01

Full Text Available Concurrent EEG and fMRI acquisitions in resting state showed a correlation between EEG power in various bands and spontaneous BOLD fluctuations. However, there is a lack of data on how changes in the complexity of brain dynamics derived from EEG reflect variations in the BOLD signal. The purpose of our study was to correlate both spectral patterns, as linear features of EEG rhythms, and nonlinear EEG dynamic complexity with neuronal activity obtained by fMRI. We examined the relationships between EEG patterns and brain activation obtained by simultaneous EEG-fMRI during the resting state condition in 25 healthy right-handed adult volunteers. Using EEG-derived regressors, we demonstrated a substantial correlation of BOLD signal changes with linear and nonlinear features of EEG. We found the most significant positive correlation of fMRI signal with delta spectral power. Beta and alpha spectral features had no reliable effect on BOLD fluctuation. However, dynamic changes of alpha peak frequency exhibited a significant association with BOLD signal increase in right-hemisphere areas. Additionally, EEG dynamic complexity as measured by the HFD of the 2–20 Hz EEG frequency range significantly correlated with the activation of cortical and subcortical limbic system areas. Our results indicate that both spectral features of EEG frequency bands and nonlinear dynamic properties of spontaneous EEG are strongly associated with fluctuations of the BOLD signal during the resting state condition.

Legibility of Sans Serif Type for Use as Body Copy in Computer Mediated Communication.

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Geske, Joel

A study examined type legibility on computer screens to determine type styles and type sizes that are most legible. Subjects, 107 college students, tested legibility of Helvetica type in 3 different sizes and 3 different faces. Results indicated no significant differences for legibility of Helvetica 12, 10, and 9 point type in the normal typeface…

AKAP18:PKA-RIIα structure reveals crucial anchor points for recognition of regulatory subunits of PKA.

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Götz, Frank; Roske, Yvette; Schulz, Maike Svenja; Autenrieth, Karolin; Bertinetti, Daniela; Faelber, Katja; Zühlke, Kerstin; Kreuchwig, Annika; Kennedy, Eileen J; Krause, Gerd; Daumke, Oliver; Herberg, Friedrich W; Heinemann, Udo; Klussmann, Enno

2016-07-01

A-kinase anchoring proteins (AKAPs) interact with the dimerization/docking (D/D) domains of regulatory subunits of the ubiquitous protein kinase A (PKA). AKAPs tether PKA to defined cellular compartments establishing distinct pools to increase the specificity of PKA signalling. Here, we elucidated the structure of an extended PKA-binding domain of AKAP18β bound to the D/D domain of the regulatory RIIα subunits of PKA. We identified three hydrophilic anchor points in AKAP18β outside the core PKA-binding domain, which mediate contacts with the D/D domain. Such anchor points are conserved within AKAPs that bind regulatory RII subunits of PKA. We derived a different set of anchor points in AKAPs binding regulatory RI subunits of PKA. In vitro and cell-based experiments confirm the relevance of these sites for the interaction of RII subunits with AKAP18 and of RI subunits with the RI-specific smAKAP. Thus we report a novel mechanism governing interactions of AKAPs with PKA. The sequence specificity of each AKAP around the anchor points and the requirement of these points for the tight binding of PKA allow the development of selective inhibitors to unequivocally ascribe cellular functions to the AKAP18-PKA and other AKAP-PKA interactions. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Ultrafast bold fMRI using single-shot spin-echo echo planar imaging

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Boujraf Said

2009-01-01

Full Text Available The choice of imaging parameters for functional MRI can have an impact on the accuracy of functional localization by affecting the image quality and the degree of blood oxygenation-dependent (BOLD contrast achieved. By improving sampling efficiency, parallel acquisition techniques such as sensitivity encoding (SENSE have been used to shorten readout trains in single-shot (SS echo planar imaging (EPI. This has been applied to susceptibility artifact reduction and improving spatial resolution. SENSE together with single-shot spin-echo (SS-SE imaging may also reduce off-resonance artifacts. The goal of this work was to investigate the BOLD response of a SENSE-adapted SE-EPI on a three Tesla scanner. Whole-brain fMRI studies of seven healthy right hand-dominant volunteers were carried out in a three Tesla scanner. fMRI was performed using an SS-SE EPI sequence with SENSE. The data was processed using statistical parametric mapping. Both, group and individual subject data analyses were performed. Individual average percentage and maximal percentage signal changes attributed to the BOLD effect in M1 were calculated for all the subjects as a function of echo time. Corresponding activation maps and the sizes of the activated clusters were also calculated. Our results show that susceptibility artifacts were reduced with the use of SENSE; and the acquired BOLD images were free of the typical quadrature artifacts of SS-EPI. Such measures are crucial at high field strengths. SS SE-EPI with SENSE offers further benefits in this regard and is more specific for oxygenation changes in the microvasculature bed. Functional brain activity can be investigated with the help of single-shot spin echo EPI using SENSE at high magnetic fields.

Post-contractile BOLD contrast in skeletal muscle at 7 T reveals inter-individual heterogeneity in the physiological responses to muscle contraction.

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Towse, Theodore F; Elder, Christopher P; Bush, Emily C; Klockenkemper, Samuel W; Bullock, Jared T; Dortch, Richard D; Damon, Bruce M

2016-12-01

Muscle blood oxygenation-level dependent (BOLD) contrast is greater in magnitude and potentially more influenced by extravascular BOLD mechanisms at 7 T than it is at lower field strengths. Muscle BOLD imaging of muscle contractions at 7 T could, therefore, provide greater or different contrast than at 3 T. The purpose of this study was to evaluate the feasibility of using BOLD imaging at 7 T to assess the physiological responses to in vivo muscle contractions. Thirteen subjects (four females) performed a series of isometric contractions of the calf muscles while being scanned in a Philips Achieva 7 T human imager. Following 2 s maximal isometric plantarflexion contractions, BOLD signal transients ranging from 0.3 to 7.0% of the pre-contraction signal intensity were observed in the soleus muscle. We observed considerable inter-subject variability in both the magnitude and time course of the muscle BOLD signal. A subset of subjects (n = 7) repeated the contraction protocol at two different repetition times (T R : 1000 and 2500 ms) to determine the potential of T 1 -related inflow effects on the magnitude of the post-contractile BOLD response. Consistent with previous reports, there was no difference in the magnitude of the responses for the two T R values (3.8 ± 0.9 versus 4.0 ± 0.6% for T R  = 1000 and 2500 ms, respectively; mean ± standard error). These results demonstrate that studies of the muscle BOLD responses to contractions are feasible at 7 T. Compared with studies at lower field strengths, post-contractile 7 T muscle BOLD contrast may afford greater insight into microvascular function and dysfunction. Copyright © 2016 John Wiley & Sons, Ltd.

Cortical layers, rhythms and BOLD signals.

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Scheeringa, René; Fries, Pascal

2017-11-03

This review investigates how laminar fMRI can complement insights into brain function derived from the study of rhythmic neuronal synchronization. Neuronal synchronization in various frequency bands plays an important role in neuronal communication between brain areas, and it does so on the backbone of layer-specific interareal anatomical projections. Feedforward projections originate predominantly in supragranular cortical layers and terminate in layer 4, and this pattern is reflected in inter-laminar and interareal directed gamma-band influences. Thus, gamma-band synchronization likely subserves feedforward signaling. By contrast, anatomical feedback projections originate predominantly in infragranular layers and terminate outside layer 4, and this pattern is reflected in inter-laminar and interareal directed alpha- and/or beta-band influences. Thus, alpha-beta band synchronization likely subserves feedback signaling. Furthermore, these rhythms explain part of the BOLD signal, with independent contributions of alpha-beta and gamma. These findings suggest that laminar fMRI can provide us with a potentially useful method to test some of the predictions derived from the study of neuronal synchronization. We review central findings regarding the role of layer-specific neuronal synchronization for brain function, and regarding the link between neuronal synchronization and the BOLD signal. We discuss the role that laminar fMRI could play by comparing it to invasive and non-invasive electrophysiological recordings. Compared to direct electrophysiological recordings, this method provides a metric of neuronal activity that is slow and indirect, but that is uniquely non-invasive and layer-specific with potentially whole brain coverage. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Crossing the implementation chasm: a proposal for bold action.

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Lorenzi, Nancy M; Novak, Laurie L; Weiss, Jacob B; Gadd, Cynthia S; Unertl, Kim M

2008-01-01

As health care organizations dramatically increase investment in information technology (IT) and the scope of their IT projects, implementation failures become critical events. Implementation failures cause stress on clinical units, increase risk to patients, and result in massive costs that are often not recoverable. At an estimated 28% success rate, the current level of investment defies management logic. This paper asserts that there are "chasms" in IT implementations that represent risky stages in the process. Contributors to the chasms are classified into four categories: design, management, organization, and assessment. The American College of Medical Informatics symposium participants recommend bold action to better understand problems and challenges in implementation and to improve the ability of organizations to bridge these implementation chasms. The bold action includes the creation of a Team Science for Implementation strategy that allows for participation from multiple institutions to address the long standing and costly implementation issues. The outcomes of this endeavor will include a new focus on interdisciplinary research and an inter-organizational knowledge base of strategies and methods to optimize implementations and subsequent achievement of organizational objectives.

Comparison between subjects with long- and short-allele carriers in the BOLD signal within amygdala during emotional tasks

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Hadi, Shamil; Siadat, Mohamad R.; Babajani-Feremi, Abbas

2012-03-01

Emotional tasks may result in a strong blood oxygen level-dependent (BOLD) signal in the amygdala in 5- HTTLRP short-allele. Reduced anterior cingulate cortex (ACC)-amygdala connectivity in short-allele provides a potential mechanistic account for the observed increase in amygdala activity. In our study, fearful and threatening facial expressions were presented to two groups of 12 subjects with long- and short-allele carriers. The BOLD signals of the left amygdala of each group were averaged to increase the signal-to-noise ratio. A Bayesian approach was used to estimate the model parameters to elucidate the underlying hemodynamic mechanism. Our results showed a positive BOLD signal in the left amygdala for short-allele individuals, and a negative BOLD signal in the same region for long-allele individuals. This is due to the fact that short-allele is associated with lower availability of serotonin transporter (5-HTT) and this leads to an increase of serotonin (5-HT) concentration in the cACC-amygdala synapse.

Spatiotemporal dynamics of the brain at rest--exploring EEG microstates as electrophysiological signatures of BOLD resting state networks.

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Yuan, Han; Zotev, Vadim; Phillips, Raquel; Drevets, Wayne C; Bodurka, Jerzy

2012-05-01

Neuroimaging research suggests that the resting cerebral physiology is characterized by complex patterns of neuronal activity in widely distributed functional networks. As studied using functional magnetic resonance imaging (fMRI) of the blood-oxygenation-level dependent (BOLD) signal, the resting brain activity is associated with slowly fluctuating hemodynamic signals (~10s). More recently, multimodal functional imaging studies involving simultaneous acquisition of BOLD-fMRI and electroencephalography (EEG) data have suggested that the relatively slow hemodynamic fluctuations of some resting state networks (RSNs) evinced in the BOLD data are related to much faster (~100 ms) transient brain states reflected in EEG signals, that are referred to as "microstates". To further elucidate the relationship between microstates and RSNs, we developed a fully data-driven approach that combines information from simultaneously recorded, high-density EEG and BOLD-fMRI data. Using independent component analysis (ICA) of the combined EEG and fMRI data, we identified thirteen microstates and ten RSNs that are organized independently in their temporal and spatial characteristics, respectively. We hypothesized that the intrinsic brain networks that are active at rest would be reflected in both the EEG data and the fMRI data. To test this hypothesis, the rapid fluctuations associated with each microstate were correlated with the BOLD-fMRI signal associated with each RSN. We found that each RSN was characterized further by a specific electrophysiological signature involving from one to a combination of several microstates. Moreover, by comparing the time course of EEG microstates to that of the whole-brain BOLD signal, on a multi-subject group level, we unraveled for the first time a set of microstate-associated networks that correspond to a range of previously described RSNs, including visual, sensorimotor, auditory, attention, frontal, visceromotor and default mode networks. These

EEG-informed fMRI analysis during a hand grip task: estimating the relationship between EEG rhythms and the BOLD signal

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Roberta eSclocco

2014-04-01

Full Text Available In the last decade, an increasing interest has arisen in investigating the relationship between the electrophysiological and hemodynamic measurements of brain activity, such as EEG and (BOLD fMRI. In particular, changes in BOLD have been shown to be associated with changes in the spectral profile of neural activity, rather than with absolute power. Concurrently, recent findings showed that different EEG rhythms are independently related to changes in the BOLD signal: therefore, it would be important to distinguish between the contributions of the different EEG rhythms to BOLD fluctuations when modeling the relationship between the two signals. Here we propose a method to perform EEG-informed fMRI analysis, in which the EEG regressors take into account both the changes in the spectral profile and the rhythms distinction. We applied it to EEG-fMRI data during a hand grip task in healthy subjects, and compared the results with those obtained by two existing models found in literature. Our results showed that the proposed method better captures the correlations between BOLD signal and EEG rhythms modulations, identifying task-related, well localized activated volumes. Furthermore, we showed that including among the regressors also EEG rhythms not primarily involved in the task enhances the performance of the analysis, even when only correlations with BOLD signal and specific EEG rhythms are explored.

Associations of resting-state fMRI functional connectivity with flow-BOLD coupling and regional vasculature.

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Tak, Sungho; Polimeni, Jonathan R; Wang, Danny J J; Yan, Lirong; Chen, J Jean

2015-04-01

There has been tremendous interest in applying functional magnetic resonance imaging-based resting-state functional connectivity (rs-fcMRI) measurements to the study of brain function. However, a lack of understanding of the physiological mechanisms of rs-fcMRI limits their ability to interpret rs-fcMRI findings. In this work, the authors examine the regional associations between rs-fcMRI estimates and dynamic coupling between the blood oxygenation level-dependent (BOLD) and cerebral blood flow (CBF), as well as resting macrovascular volume. Resting-state BOLD and CBF data were simultaneously acquired using a dual-echo pseudocontinuous arterial spin labeling (pCASL) technique, whereas macrovascular volume fraction was estimated using time-of-flight MR angiography. Functional connectivity within well-known functional networks—including the default mode, frontoparietal, and primary sensory-motor networks—was calculated using a conventional seed-based correlation approach. They found the functional connectivity strength to be significantly correlated with the regional increase in CBF-BOLD coupling strength and inversely proportional to macrovascular volume fraction. These relationships were consistently observed within all functional networks considered. Their findings suggest that highly connected networks observed using rs-fcMRI are not likely to be mediated by common vascular drainage linking distal cortical areas. Instead, high BOLD functional connectivity is more likely to reflect tighter neurovascular connections, attributable to neuronal pathways.

Towards a mechanistic understanding of vulnerability to hook-and-line fishing: Boldness as the basic target of angling-induced selection

DEFF Research Database (Denmark)

Klefoth, Thomas; Skov, Christian; Kuparinen, Anna

2017-01-01

by juvenile growth rate, while morphological traits were only weakly related to angling vulnerability. In addition, we found juvenile growth rate to be moderately correlated with boldness. Hence, direct selection on boldness will also induce indirect selection on juvenile growth and vice versa, but given......In passively operated fishing gear, boldness-related behaviors should fundamentally affect the vulnerability of individual fish and thus be under fisheries selection. To test this hypothesis, we used juvenile common-garden reared carp (Cyprinus carpio) within a narrow size range to investigate...... the mechanistic basis of behavioral selection caused by angling. We focused on one key personality trait (i.e., boldness), measured in groups within ponds, two morphological traits (body shape and head shape), and one life-history trait (juvenile growth capacity) and studied mean standardized selection gradients...

The effect of sleep deprivation on BOLD activity elicited by a divided attention task.

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Jackson, Melinda L; Hughes, Matthew E; Croft, Rodney J; Howard, Mark E; Crewther, David; Kennedy, Gerard A; Owens, Katherine; Pierce, Rob J; O'Donoghue, Fergal J; Johnston, Patrick

2011-06-01

Sleep loss, widespread in today's society and associated with a number of clinical conditions, has a detrimental effect on a variety of cognitive domains including attention. This study examined the sequelae of sleep deprivation upon BOLD fMRI activation during divided attention. Twelve healthy males completed two randomized sessions; one after 27 h of sleep deprivation and one after a normal night of sleep. During each session, BOLD fMRI was measured while subjects completed a cross-modal divided attention task (visual and auditory). After normal sleep, increased BOLD activation was observed bilaterally in the superior frontal gyrus and the inferior parietal lobe during divided attention performance. Subjects reported feeling significantly more sleepy in the sleep deprivation session, and there was a trend towards poorer divided attention task performance. Sleep deprivation led to a down regulation of activation in the left superior frontal gyrus, possibly reflecting an attenuation of top-down control mechanisms on the attentional system. These findings have implications for understanding the neural correlates of divided attention and the neurofunctional changes that occur in individuals who are sleep deprived.

Transfer function between EEG and BOLD signals of epileptic activity

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Marco eLeite

2013-01-01

Full Text Available Simultaneous EEG-fMRI recordings have seen growing application in the evaluation of epilepsy, namely in the characterization of brain networks related to epileptic activity. In EEG-correlated fMRI studies, epileptic events are usually described as boxcar signals based on the timing information retrieved from the EEG, and subsequently convolved with a heamodynamic response function to model the associated BOLD changes. Although more flexible approaches may allow a higher degree of complexity for the haemodynamics, the issue of how to model these dynamics based on the EEG remains an open question. In this work, a new methodology for the integration of simultaneous EEG-fMRI data in epilepsy is proposed, which incorporates a transfer function from the EEG to the BOLD signal. Independent component analysis (ICA of the EEG is performed, and a number of metrics expressing different models of the EEG-BOLD transfer function are extracted from the resulting time courses. These metrics are then used to predict the fMRI data and to identify brain areas associated with the EEG epileptic activity. The methodology was tested on both ictal and interictal EEG-fMRI recordings from one patient with a hypothalamic hamartoma. When compared to the conventional analysis approach, plausible, consistent and more significant activations were obtained. Importantly, frequency-weighted EEG metrics yielded superior results than those weighted solely on the EEG power, which comes in agreement with previous literature. Reproducibility, specificity and sensitivity should be addressed in an extended group of patients in order to further validate the proposed methodology and generalize the presented proof of concept.

Interleaved quantitative BOLD: Combining extravascular R2' - and intravascular R2-measurements for estimation of deoxygenated blood volume and hemoglobin oxygen saturation.

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Lee, Hyunyeol; Englund, Erin K; Wehrli, Felix W

2018-03-23

Quantitative BOLD (qBOLD), a non-invasive MRI method for assessment of hemodynamic and metabolic properties of the brain in the baseline state, provides spatial maps of deoxygenated blood volume fraction (DBV) and hemoglobin oxygen saturation (HbO 2 ) by means of an analytical model for the temporal evolution of free-induction-decay signals in the extravascular compartment. However, mutual coupling between DBV and HbO 2 in the signal model results in considerable estimation uncertainty precluding achievement of a unique set of solutions. To address this problem, we developed an interleaved qBOLD method (iqBOLD) that combines extravascular R 2 ' and intravascular R 2 mapping techniques so as to obtain prior knowledge for the two unknown parameters. To achieve these goals, asymmetric spin echo and velocity-selective spin-labeling (VSSL) modules were interleaved in a single pulse sequence. Prior to VSSL, arterial blood and CSF signals were suppressed to produce reliable estimates for cerebral venous blood volume fraction (CBV v ) as well as venous blood R 2 (to yield HbO 2 ). Parameter maps derived from the VSSL module were employed to initialize DBV and HbO 2 in the qBOLD processing. Numerical simulations and in vivo experiments at 3 T were performed to evaluate the performance of iqBOLD in comparison to the parent qBOLD method. Data obtained in eight healthy subjects yielded plausible values averaging 60.1 ± 3.3% for HbO 2 and 3.1 ± 0.5 and 2.0 ± 0.4% for DBV in gray and white matter, respectively. Furthermore, the results show that prior estimates of CBV v and HbO 2 from the VSSL component enhance the solution stability in the qBOLD processing, and thus suggest the feasibility of iqBOLD as a promising alternative to the conventional technique for quantifying neurometabolic parameters. Copyright © 2018. Published by Elsevier Inc.

Logistic simulation of the Cryomagnet Activities at Point 18

CERN Document Server

Lundgren, M

2002-01-01

The purpose of this work is to build a model in a simulation software (AutoMod) that can be used to improve the logistic planning and scheduling of the assembly and installation procedures concerning the Cryomagnets for the LHC project at point 18. The model should provide necessary information that simplifies the scheduling of activities based on time and resource availability. This report contains the results gathered from these simulations. This work been performed in the framework of a Master thesis. It is based on data available in November 2001. It has not been updated following latter decisions but the methodology and main results are still valid.

Abnormal Striatal BOLD Responses to Reward Anticipation and Reward Delivery in ADHD

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Furukawa, Emi; Bado, Patricia; Tripp, Gail; Mattos, Paulo; Wickens, Jeff R.; Bramati, Ivanei E.; Alsop, Brent; Ferreira, Fernanda Meireles; Lima, Debora; Tovar-Moll, Fernanda; Sergeant, Joseph A.; Moll, Jorge

2014-01-01

Altered reward processing has been proposed to contribute to the symptoms of attention deficit hyperactivity disorder (ADHD). The neurobiological mechanism underlying this alteration remains unclear. We hypothesize that the transfer of dopamine release from reward to reward-predicting cues, as normally observed in animal studies, may be deficient in ADHD. Functional magnetic resonance imaging (fMRI) was used to investigate striatal responses to reward-predicting cues and reward delivery in a classical conditioning paradigm. Data from 14 high-functioning and stimulant-naïve young adults with elevated lifetime symptoms of ADHD (8 males, 6 females) and 15 well-matched controls (8 males, 7 females) were included in the analyses. During reward anticipation, increased blood-oxygen-level-dependent (BOLD) responses in the right ventral and left dorsal striatum were observed in controls, but not in the ADHD group. The opposite pattern was observed in response to reward delivery; the ADHD group demonstrated significantly greater BOLD responses in the ventral striatum bilaterally and the left dorsal striatum relative to controls. In the ADHD group, the number of current hyperactivity/impulsivity symptoms was inversely related to ventral striatal responses during reward anticipation and positively associated with responses to reward. The BOLD response patterns observed in the striatum are consistent with impaired predictive dopamine signaling in ADHD, which may explain altered reward-contingent behaviors and symptoms of ADHD. PMID:24586543

Real-time fMRI neurofeedback of the mediodorsal and anterior thalamus enhances correlation between thalamic BOLD activity and alpha EEG rhythm.

Science.gov (United States)

Zotev, Vadim; Misaki, Masaya; Phillips, Raquel; Wong, Chung Ki; Bodurka, Jerzy

2018-02-01

Real-time fMRI neurofeedback (rtfMRI-nf) with simultaneous EEG allows volitional modulation of BOLD activity of target brain regions and investigation of related electrophysiological activity. We applied this approach to study correlations between thalamic BOLD activity and alpha EEG rhythm. Healthy volunteers in the experimental group (EG, n = 15) learned to upregulate BOLD activity of the target region consisting of the mediodorsal (MD) and anterior (AN) thalamic nuclei using rtfMRI-nf during retrieval of happy autobiographical memories. Healthy subjects in the control group (CG, n = 14) were provided with a sham feedback. The EG participants were able to significantly increase BOLD activities of the MD and AN. Functional connectivity between the MD and the inferior precuneus was significantly enhanced during the rtfMRI-nf task. Average individual changes in the occipital alpha EEG power significantly correlated with the average MD BOLD activity levels for the EG. Temporal correlations between the occipital alpha EEG power and BOLD activities of the MD and AN were significantly enhanced, during the rtfMRI-nf task, for the EG compared to the CG. Temporal correlations with the alpha power were also significantly enhanced for the posterior nodes of the default mode network, including the precuneus/posterior cingulate, and for the dorsal striatum. Our findings suggest that the temporal correlation between the MD BOLD activity and posterior alpha EEG power is modulated by the interaction between the MD and the inferior precuneus, reflected in their functional connectivity. Our results demonstrate the potential of the rtfMRI-nf with simultaneous EEG for noninvasive neuromodulation studies of human brain function. © 2017 Wiley Periodicals, Inc.

Wavelet entropy of BOLD time series : an application to Rolandic epilepsy

NARCIS (Netherlands)

Gupta, Lalit; Jansen, Jacobus F.A.; Hofman, Paul A.M.; Besseling, René M.H.; de Louw, Anton J.A.; Aldenkamp, Albert P.; Backes, Walter H.

2017-01-01

Purpose: To assess the wavelet entropy for the characterization of intrinsic aberrant temporal irregularities in the time series of resting-state blood-oxygen-level-dependent (BOLD) signal fluctuations. Further, to evaluate the temporal irregularities (disorder/order) on a voxel-by-voxel basis in

Evidence accumulation detected in BOLD signal using slow perceptual decision making

NARCIS (Netherlands)

Krueger, Paul M.; van Vugt, Marieke K.; Simen, Patrick; Nystrom, Leigh; Holmes, Philip; Cohen, Jonathan D.

2017-01-01

BACKGROUND: We assessed whether evidence accumulation could be observed in the BOLD signal during perceptual decision making. This presents a challenge since the hemodynamic response is slow, while perceptual decisions are typically fast. NEW METHOD: Guided by theoretical predictions of the drift

Physiologic characterization of inflammatory arthritis in a rabbit model with BOLD and DCE MRI at 1.5 Tesla

Energy Technology Data Exchange (ETDEWEB)

Nasui, Otilia C.; Chan, Michael W.; Nathanael, George; Rayner, Tammy; Weiss, Ruth; Detzler, Garry; Zhong, Anguo [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto, ON (Canada); Crawley, Adrian [University of Toronto, Department of Medical Imaging, Toronto, ON (Canada); Toronto Western Hospital, Department of Medical Imaging, Toronto, ON (Canada); Miller, Elka [Children' s Hospital of Eastern Ontario (CHEO), Department of Diagnostic Imaging, Ottawa, ON (Canada); Belik, Jaques [The Hospital for Sick Children, Department of Neonatology, Toronto, ON (Canada); Cheng, Hai-Ling; Kassner, Andrea; Doria, Andrea S. [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto, ON (Canada); University of Toronto, Department of Medical Imaging, Toronto, ON (Canada); Moineddin, Rahim [Department of Public Health, Family and Community Medicine, Toronto, ON (Canada); Jong, Roland; Rogers, Marianne [Mount Sinai Hospital, Department of Pathology, Toronto, ON (Canada)

2014-11-15

Our aim was to test the feasibility of blood oxygen level dependent magnetic resonance imaging (BOLD MRI) and dynamic contrast-enhanced (DCE) MRI to monitor periarticular hypoxic/inflammatory changes over time in a juvenile rabbit model of arthritis. We examined arthritic and contralateral nonarthritic knees of 21 juvenile rabbits at baseline and days 1,14, and 28 after induction of arthritis by unilateral intra-articular injection of carrageenin with BOLD and DCE MRI at 1.5 Tesla (T). Nine noninjected rabbits served as controls. Associations between BOLD and DCE-MRI and corresponding intra-articular oxygen pressure (PO{sub 2}) and blood flow [blood perfusion units (BPU)] (polarographic probes, reference standards) or clinical-histological data were measured by correlation coefficients. Percentage BOLD MRI change obtained in contralateral knees correlated moderately with BPU on day 0 (r = -0.51, p = 0.02) and excellently on day 28 (r = -0.84, p = 0.03). A moderate correlation was observed between peak enhancement DCE MRI (day 1) and BPU measurements in arthritic knees (r = 0.49, p = 0.04). In acute arthritis, BOLD and DCE MRI highly correlated (r = 0.89, p = 0.04; r = 1.0, p < 0.0001) with histological scores in arthritic knees. The proposed techniques are feasible to perform at 1.5 T, and they hold potential as surrogate measures to monitor hypoxic and inflammatory changes over time in arthritis at higher-strength MRI fields. (orig.)

Using BOLD imaging to measure renal oxygenation dynamics in rats injected with diuretics

International Nuclear Information System (INIS)

Kusakabe, Yoshinori; Matsushita, Taro; Honda, Saori; Okada, Sakie; Murase, Kenya

2010-01-01

We used blood oxygenation level-dependent magnetic resonance imaging (BOLD MRI) to measure renal oxygenation dynamics in rats injected with diuretics and evaluated diuretic effect on renal oxygenation. We performed BOLD MRI studies in 32 rats using a 1.5-tesla MR imaging system for animal experiments. We intravenously injected rats with saline (n=7), furosemide (n=7), acetazolamide (n=6), or mannitol (n=6). For controls, 6 rats were not injected with drugs. We estimated the apparent transverse relaxation rate (R 2 *) from the apparent transverse relaxation time (T 2 *)-weighted images and measured the time course of R 2 * at 4-min intervals over approximately 30 min. Compared with preadministration values, the R 2 * value did not change significantly in either the cortex or medulla in the control and mannitol groups but decreased significantly in the saline group; the R 2 * value significantly decreased in the medulla but did not change significantly in the cortex in the furosemide group; and the R 2 * value significantly increased in the medulla and significantly decreased in the cortex in the acetazolamide group. Our study results suggest that BOLD MRI is useful for evaluating the dynamics of renal oxygenation in response to various diuretics in the renal cortex and in the medulla. (author)

Using pulse oximetry to account for high and low frequency physiological artifacts in the BOLD signal.

Science.gov (United States)

Verstynen, Timothy D; Deshpande, Vibhas

2011-04-15

The BOLD signal not only reflects changes in local neural activity, but also exhibits variability from physiological processes like cardiac rhythms and breathing. We investigated how both of these physiological sources are reflected in the pulse oximetry (PO) signal, a direct measure of blood oxygenation, and how this information can be used to account for different types of noise in the BOLD response. Measures of heart rate, respiration and PO were simultaneously recorded while neurologically healthy participants performed an eye-movement task in a 3T MRI. PO exhibited power in frequencies that matched those found in the independently recorded cardiac and respiration signals. Using the phasic and aphasic properties of these signals as nuisance regressors, we found that the different frequency components of the PO signal could be used to identify different types of physiological artifacts in the BOLD response. A comparison of different physiological noise models found that a simple, down-sampled version of the PO signal improves the estimation of task-relevant statistics nearly as well as more established noise models that may run the risk of over-parameterization. These findings suggest that the PO signal captures multiple sources of physiological noise in the BOLD response and provides a simple and efficient way of modeling these noise sources in subsequent analysis. Copyright © 2011 Elsevier Inc. All rights reserved.

Clinical Significance of F 18 FP CIT Dual Time Point PET Imaging in Idiopathic Parkinson's Disease

International Nuclear Information System (INIS)

Oh, Jin Kyoung; Yoo, Ik Dong; Seo, Ye Young; Chung, Youg An; Yoo, Ie Ryung; Kim, Sung Hoon; Song, In Uk

2011-01-01

The purpose of this study was to investigate the diagnostic value of dual time point F 18 FP CIT PET imaging in idiopathic Parkinson's disease (PD). Twenty four patients with PD (mean age 69.6) and 18 healthy people (mean age 70.26) underwent two sequential PET/CT scans (dual time point imaging) at 90 and 210 min after F 18 FP CIT injection. Tracer activity of region of interest was measured in the caudate, putamen and a reference region in the brain from both time points. The outcome parameter was the striatooccipital ratio (SOR). Normal SOR values were obtained in the control group. The percent change in tracer activity between 90 and 210 min images was calculated. The SOR values and the percent change in tracer activity were compared between the patients and healthy control group. The SOR values for the caudate, anterior and posterior putamen at both 90 and 210 min images were significantly reduced in the patients with PD. The lowest P value was obtained for the anterior and posterior putamen (p<0.001) at both time points. There were significant differences of the percent change in tracer activity for the anterior and posterior putamen in the two groups (p=0.01) F 18 FP CIT PET scans at 90 and 210 min after injection are both able to diagnose PD. Therefore, the 90 min image by itself in sufficient for diagnosing PD.

Co-localization between the BOLD response and epileptiform discharges recorded by simultaneous intracranial EEG-fMRI at 3 T

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Yahya Aghakhani

2015-01-01

Conclusions: iEEG-fMRI is a feasible and low-risk method for assessment of hemodynamic changes of very focal IEDs that may not be recorded by scalp EEG. A high concordance rate between the location of the BOLD response and IEDs was seen for mesial temporal (6/7 IEDs. Significant BOLD activation was also seen in areas distant from the active electrode and these sites exhibited maximal BOLD activation in the majority of cases. This implies that iEEG-fMRI may further describe the areas involved in the generation of IEDs beyond the vicinity of the electrode(s.

Comparison of diffusion-weighted fMRI and BOLD fMRI responses in a verbal working memory task

International Nuclear Information System (INIS)

Aso, Toshihiko; Urayama, Shin-ichi; Fukuyama, Hidenao; Le Bihan, Denis

2013-01-01

Diffusion-weighted functional MRI (DfMRI) has been reported to have a different response pattern in the visual cortex than that of BOLD-fMRI. Especially, the DfMRI signal shows a constantly faster response at both onset and offset of the stimulus, suggesting that the DfMRI signal might be more directly linked to neuronal events than the hemodynamic response. However, because the DfMRI response also contains a residual sensitivity to BOLD this hypothesis has been challenged. Using a verbal working memory task we show that the DfMRI time-course features are preserved outside visual cortices, but also less liable to between-subject/between-regional variation than the BOLD response. The overall findings not only support the feasibility of DfMRI as an approach for functional brain imaging, but also strengthen the uniqueness of the DfMRI signal origin. (authors)

Ghrelin modulates the fMRI BOLD response of homeostatic and hedonic brain centers regulating energy balance in the rat.

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Miklós Sárvári

Full Text Available The orexigenic gut-brain peptide, ghrelin and its G-protein coupled receptor, the growth hormone secretagogue receptor 1a (GHS-R1A are pivotal regulators of hypothalamic feeding centers and reward processing neuronal circuits of the brain. These systems operate in a cooperative manner and receive a wide array of neuronal hormone/transmitter messages and metabolic signals. Functional magnetic resonance imaging was employed in the current study to map BOLD responses to ghrelin in different brain regions with special reference on homeostatic and hedonic regulatory centers of energy balance. Experimental groups involved male, ovariectomized female and ovariectomized estradiol-replaced rats. Putative modulation of ghrelin signaling by endocannabinoids was also studied. Ghrelin-evoked effects were calculated as mean of the BOLD responses 30 minutes after administration. In the male rat, ghrelin evoked a slowly decreasing BOLD response in all studied regions of interest (ROI within the limbic system. This effect was antagonized by pretreatment with GHS-R1A antagonist JMV2959. The comparison of ghrelin effects in the presence or absence of JMV2959 in individual ROIs revealed significant changes in the prefrontal cortex, nucleus accumbens of the telencephalon, and also within hypothalamic centers like the lateral hypothalamus, ventromedial nucleus, paraventricular nucleus and suprachiasmatic nucleus. In the female rat, the ghrelin effects were almost identical to those observed in males. Ovariectomy and chronic estradiol replacement had no effect on the BOLD response. Inhibition of the endocannabinoid signaling by rimonabant significantly attenuated the response of the nucleus accumbens and septum. In summary, ghrelin can modulate hypothalamic and mesolimbic structures controlling energy balance in both sexes. The endocannabinoid signaling system contributes to the manifestation of ghrelin's BOLD effect in a region specific manner. In females, the

Patterns of cortical oscillations organize neural activity into whole-brain functional networks evident in the fMRI BOLD signal

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Jennifer C Whitman

2013-03-01

Full Text Available Recent findings from electrophysiology and multimodal neuroimaging have elucidated the relationship between patterns of cortical oscillations evident in EEG / MEG and the functional brain networks evident in the BOLD signal. Much of the existing literature emphasized how high-frequency cortical oscillations are thought to coordinate neural activity locally, while low-frequency oscillations play a role in coordinating activity between more distant brain regions. However, the assignment of different frequencies to different spatial scales is an oversimplification. A more informative approach is to explore the arrangements by which these low- and high-frequency oscillations work in concert, coordinating neural activity into whole-brain functional networks. When relating such networks to the BOLD signal, we must consider how the patterns of cortical oscillations change at the same speed as cognitive states, which often last less than a second. Consequently, the slower BOLD signal may often reflect the summed neural activity of several transient network configurations. This temporal mismatch can be circumvented if we use spatial maps to assess correspondence between oscillatory networks and BOLD networks.

In contrast to BOLD: signal enhancement by extravascular water protons as an alternative mechanism of endogenous fMRI signal change.

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Figley, Chase R; Leitch, Jordan K; Stroman, Patrick W

2010-10-01

Despite the popularity and widespread application of functional magnetic resonance imaging (fMRI) in recent years, the physiological bases of signal change are not yet fully understood. Blood oxygen level-dependant (BOLD) contrast - attributed to local changes in blood flow and oxygenation, and therefore magnetic susceptibility - has become the most prevalent means of functional neuroimaging. However, at short echo times, spin-echo sequences show considerable deviations from the BOLD model, implying a second, non-BOLD component of signal change. This has been dubbed "signal enhancement by extravascular water protons" (SEEP) and is proposed to result from proton-density changes associated with cellular swelling. Given that such changes are independent of magnetic susceptibility, SEEP may offer new and improved opportunities for carrying out fMRI in regions with close proximity to air-tissue and/or bone-tissue interfaces (e.g., the prefrontal cortex and spinal cord), as well as regions close to large blood vessels, which may not be ideally suited for BOLD imaging. However, because of the interdisciplinary nature of the literature, there has yet to be a thorough synthesis, tying together the various and sometimes disparate aspects of SEEP theory. As such, we aim to provide a concise yet comprehensive overview of SEEP, including recent and compelling evidence for its validity, its current applications and its future relevance to the rapidly expanding field of functional neuroimaging. Before presenting the evidence for a non-BOLD component of endogenous functional contrast, and to enable a more critical review for the nonexpert reader, we begin by reviewing the fundamental principles underlying BOLD theory. Copyright © 2010 Elsevier Inc. All rights reserved.

Changes in BOLD and ADC weighted imaging in acute hypoxia during sea-level and altitude adapted states

DEFF Research Database (Denmark)

Rostrup, Egill; Larsson, Henrik B.W.; Born, Alfred P.

2005-01-01

possible structural changes as measured by diffusion weighted imaging. Eleven healthy sea-level residents were studied after 5 weeks of adaptation to high altitude conditions at Chacaltaya, Bolivia (5260 m). The subjects were studied immediately after return to sea-level in hypoxic and normoxic conditions...... was slightly elevated in high altitude as compared to sea-level adaptation. It is concluded that hypoxia significantly diminishes the BOLD response, and the mechanisms underlying this finding are discussed. Furthermore, altitude adaptation may influence both the magnitude of the activation-related response......, and the examinations repeated 6 months later after re-adaptation to sea-level conditions. The BOLD response, measured at 1.5 T, was severely reduced during acute hypoxia both in the altitude and sea-level adapted states (50% reduction during an average S(a)O(2) of 75%). On average, the BOLD response magnitude was 23...

Distinct BOLD activation profiles following central and peripheral oxytocin administration in awake rats

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Craig F Ferris

2015-09-01

Full Text Available A growing body of literature has suggested that intranasal oxytocin (OT or other systemic routes of administration can alter prosocial behavior, presumably by directly activating OT sensitive neural circuits in the brain. Yet there is no clear evidence that OT given peripherally can cross the blood-brain-barrier at levels sufficient to engage the OT receptor. To address this issue we examined changes in blood oxygen level dependent (BOLD signal intensity in response to peripheral OT injections (0.1, 0.5 or 2.5 mg/kg during functional magnetic resonance (fMRI in awake rats imaged at 7.0 tesla. These data were compared to OT (1ug/5 µl given directly to the brain via the lateral cerebroventricle. Using a 3D annotated MRI atlas of the rat brain segmented into 171 brain areas and computational analysis we reconstructed the distributed integrated neural circuits identified with BOLD fMRI following central and peripheral OT. Both routes of administration caused significant changes in BOLD signal within the first 10 min of administration. As expected, central OT activated a majority of brain areas known to express a high density of OT receptors e.g., lateral septum, subiculum, shell of the accumbens, bed nucleus of the stria terminalis. This profile of activation was not matched by peripheral OT. The change in BOLD signal to peripheral OT did not show any discernible dose-response. Interestingly, peripheral OT affected all subdivisions of the olfactory bulb, in addition to the cerebellum and several brainstem areas relevant to the autonomic nervous system, including the solitary tract nucleus. The results from this imaging study do not support a direct central action of peripheral OT on the brain. Instead, the patterns of brain activity suggest that peripheral OT may interact at the level of the olfactory bulb and through sensory afferents from the autonomic nervous system to influence brain activity.

Distinct BOLD Activation Profiles Following Central and Peripheral Oxytocin Administration in Awake Rats.

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Ferris, Craig F; Yee, Jason R; Kenkel, William M; Dumais, Kelly Marie; Moore, Kelsey; Veenema, Alexa H; Kulkarni, Praveen; Perkybile, Allison M; Carter, C Sue

2015-01-01

A growing body of literature has suggested that intranasal oxytocin (OT) or other systemic routes of administration can alter prosocial behavior, presumably by directly activating OT sensitive neural circuits in the brain. Yet there is no clear evidence that OT given peripherally can cross the blood-brain barrier at levels sufficient to engage the OT receptor. To address this issue we examined changes in blood oxygen level-dependent (BOLD) signal intensity in response to peripheral OT injections (0.1, 0.5, or 2.5 mg/kg) during functional magnetic resonance imaging (fMRI) in awake rats imaged at 7.0 T. These data were compared to OT (1 μg/5 μl) given directly to the brain via the lateral cerebroventricle. Using a 3D annotated MRI atlas of the rat brain segmented into 171 brain areas and computational analysis, we reconstructed the distributed integrated neural circuits identified with BOLD fMRI following central and peripheral OT. Both routes of administration caused significant changes in BOLD signal within the first 10 min of administration. As expected, central OT activated a majority of brain areas known to express a high density of OT receptors, e.g., lateral septum, subiculum, shell of the accumbens, bed nucleus of the stria terminalis. This profile of activation was not matched by peripheral OT. The change in BOLD signal to peripheral OT did not show any discernible dose-response. Interestingly, peripheral OT affected all subdivisions of the olfactory bulb, in addition to the cerebellum and several brainstem areas relevant to the autonomic nervous system, including the solitary tract nucleus. The results from this imaging study do not support a direct central action of peripheral OT on the brain. Instead, the patterns of brain activity suggest that peripheral OT may interact at the level of the olfactory bulb and through sensory afferents from the autonomic nervous system to influence brain activity.

Dual-time-point O-(2-[18F]fluoroethyl)-L-tyrosine PET for grading of cerebral gliomas

International Nuclear Information System (INIS)

Lohmann, Philipp; Herzog, Hans; Rota Kops, Elena; Stoffels, Gabriele; Judov, Natalie; Filss, Christian; Tellmann, Lutz; Galldiks, Norbert; Weiss, Carolin; Sabel, Michael; Coenen, Heinz Hubert; Shah, Nadim Jon; Langen, Karl-Josef

2015-01-01

We aimed to evaluate the diagnostic potential of dual-time-point imaging with positron emission tomography (PET) using O-(2-[ 18 F]fluoroethyl)-L-tyrosine ( 18 F-FET) for non-invasive grading of cerebral gliomas compared with a dynamic approach. Thirty-six patients with histologically confirmed cerebral gliomas (21 primary, 15 recurrent; 24 high-grade, 12 low-grade) underwent dynamic PET from 0 to 50 min post-injection (p.i.) of 18 F-FET, and additionally from 70 to 90 min p.i. Mean tumour-to-brain ratios (TBR mean ) of 18 F-FET uptake were determined in early (20-40 min p.i.) and late (70-90 min p.i.) examinations. Time-activity curves (TAC) of the tumours from 0 to 50 min after injection were assigned to different patterns. The diagnostic accuracy of changes of 18 F-FET uptake between early and late examinations for tumour grading was compared to that of curve pattern analysis from 0 to 50 min p.i. of 18 F-FET. The diagnostic accuracy of changes of the TBR mean of 18 F-FET PET uptake between early and late examinations for the identification of HGG was 81 % (sensitivity 83 %; specificity 75 %; cutoff - 8 %; p < 0.001), and 83 % for curve pattern analysis (sensitivity 88 %; specificity 75 %; p < 0.001). Dual-time-point imaging of 18 F-FET uptake in gliomas achieves diagnostic accuracy for tumour grading that is similar to the more time-consuming dynamic data acquisition protocol. (orig.)

Hypercapnic normalization of BOLD fMRI: comparison across field strengths and pulse sequences

DEFF Research Database (Denmark)

Cohen, Eric R.; Rostrup, Egill; Sidaros, Karam

2004-01-01

to be more accurately localized and quantified based on changes in venous blood oxygenation alone. The normalized BOLD signal induced by the motor task was consistent across different magnetic fields and pulse sequences, and corresponded well with cerebral blood flow measurements. Our data suggest...... size, as well as experimental, such as pulse sequence and static magnetic field strength (B(0)). Thus, it is difficult to compare task-induced fMRI signals across subjects, field strengths, and pulse sequences. This problem can be overcome by normalizing the neural activity-induced BOLD fMRI response...... for global stimulation, subjects breathed a 5% CO(2) gas mixture. Under all conditions, voxels containing primarily large veins and those containing primarily active tissue (i.e., capillaries and small veins) showed distinguishable behavior after hypercapnic normalization. This allowed functional activity...

Spatiotemporal alignment of in utero BOLD-MRI series.

Science.gov (United States)

Turk, Esra Abaci; Luo, Jie; Gagoski, Borjan; Pascau, Javier; Bibbo, Carolina; Robinson, Julian N; Grant, P Ellen; Adalsteinsson, Elfar; Golland, Polina; Malpica, Norberto

2017-08-01

To present a method for spatiotemporal alignment of in-utero magnetic resonance imaging (MRI) time series acquired during maternal hyperoxia for enabling improved quantitative tracking of blood oxygen level-dependent (BOLD) signal changes that characterize oxygen transport through the placenta to fetal organs. The proposed pipeline for spatiotemporal alignment of images acquired with a single-shot gradient echo echo-planar imaging includes 1) signal nonuniformity correction, 2) intravolume motion correction based on nonrigid registration, 3) correction of motion and nonrigid deformations across volumes, and 4) detection of the outlier volumes to be discarded from subsequent analysis. BOLD MRI time series collected from 10 pregnant women during 3T scans were analyzed using this pipeline. To assess pipeline performance, signal fluctuations between consecutive timepoints were examined. In addition, volume overlap and distance between manual region of interest (ROI) delineations in a subset of frames and the delineations obtained through propagation of the ROIs from the reference frame were used to quantify alignment accuracy. A previously demonstrated rigid registration approach was used for comparison. The proposed pipeline improved anatomical alignment of placenta and fetal organs over the state-of-the-art rigid motion correction methods. In particular, unexpected temporal signal fluctuations during the first normoxia period were significantly decreased (P quantitative studies of placental function by improving spatiotemporal alignment across placenta and fetal organs. 1 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:403-412. © 2017 International Society for Magnetic Resonance in Medicine.

Boldness and intermittent locomotion in the bluegill sunfish, Lepomis macrochirus

OpenAIRE

Alexander D.M. Wilson; Jean-Guy J. Godin

2009-01-01

Intermittent locomotion, characterized by moves interspersed with pauses, is a common pattern of locomotion in animals, but its ecological and evolutionary significance relative to continuous locomotion remains poorly understood. Although many studies have examined individual differences in both intermittent locomotion and boldness separately, to our knowledge, no study to date has investigated the relationship between these 2 traits. Characterizing and understanding this relationship is impo...

Wavelet entropy of BOLD time series: An application to Rolandic epilepsy.

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Gupta, Lalit; Jansen, Jacobus F A; Hofman, Paul A M; Besseling, René M H; de Louw, Anton J A; Aldenkamp, Albert P; Backes, Walter H

2017-12-01

To assess the wavelet entropy for the characterization of intrinsic aberrant temporal irregularities in the time series of resting-state blood-oxygen-level-dependent (BOLD) signal fluctuations. Further, to evaluate the temporal irregularities (disorder/order) on a voxel-by-voxel basis in the brains of children with Rolandic epilepsy. The BOLD time series was decomposed using the discrete wavelet transform and the wavelet entropy was calculated. Using a model time series consisting of multiple harmonics and nonstationary components, the wavelet entropy was compared with Shannon and spectral (Fourier-based) entropy. As an application, the wavelet entropy in 22 children with Rolandic epilepsy was compared to 22 age-matched healthy controls. The images were obtained by performing resting-state functional magnetic resonance imaging (fMRI) using a 3T system, an 8-element receive-only head coil, and an echo planar imaging pulse sequence ( T2*-weighted). The wavelet entropy was also compared to spectral entropy, regional homogeneity, and Shannon entropy. Wavelet entropy was found to identify the nonstationary components of the model time series. In Rolandic epilepsy patients, a significantly elevated wavelet entropy was observed relative to controls for the whole cerebrum (P = 0.03). Spectral entropy (P = 0.41), regional homogeneity (P = 0.52), and Shannon entropy (P = 0.32) did not reveal significant differences. The wavelet entropy measure appeared more sensitive to detect abnormalities in cerebral fluctuations represented by nonstationary effects in the BOLD time series than more conventional measures. This effect was observed in the model time series as well as in Rolandic epilepsy. These observations suggest that the brains of children with Rolandic epilepsy exhibit stronger nonstationary temporal signal fluctuations than controls. 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1728-1737. © 2017 International Society for Magnetic

The dependencies of fronto-parietal BOLD responses evoked by covert visual search suggest eye-centred coding.

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Atabaki, A; Dicke, P W; Karnath, H-O; Thier, P

2013-04-01

Visual scenes explored covertly are initially represented in a retinal frame of reference (FOR). On the other hand, 'later' stages of the cortical network allocating spatial attention most probably use non-retinal or non-eye-centred representations as they may ease the integration of different sensory modalities for the formation of supramodal representations of space. We tested if the cortical areas involved in shifting covert attention are based on eye-centred or non-eye-centred coding by using functional magnetic resonance imaging. Subjects were scanned while detecting a target item (a regularly oriented 'L') amidst a set of distractors (rotated 'L's). The array was centred either 5° right or left of the fixation point, independent of eye-gaze orientation, the latter varied in three steps: straight relative to the head, 10° left or 10° right. A quantitative comparison of the blood-oxygen-level-dependent (BOLD) responses for the three eye-gaze orientations revealed stronger BOLD responses in the right intraparietal sulcus (IPS) and the right frontal eye field (FEF) for search in the contralateral (i.e. left) eye-centred space, independent of whether the array was located in the right or left head-centred hemispace. The left IPS showed the reverse pattern, i.e. an activation by search in the right eye-centred hemispace. In other words, the IPS and the right FEF, members of the cortical network underlying covert search, operate in an eye-centred FOR. © 2013 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Accounting for the role of hematocrit in between-subject variations of MRI-derived baseline cerebral hemodynamic parameters and functional BOLD responses.

Science.gov (United States)

Xu, Feng; Li, Wenbo; Liu, Peiying; Hua, Jun; Strouse, John J; Pekar, James J; Lu, Hanzhang; van Zijl, Peter C M; Qin, Qin

2018-01-01

Baseline hematocrit fraction (Hct) is a determinant for baseline cerebral blood flow (CBF) and between-subject variation of Hct thus causes variation in task-based BOLD fMRI signal changes. We first verified in healthy volunteers (n = 12) that Hct values can be derived reliably from venous blood T 1 values by comparison with the conventional lab test. Together with CBF measured using phase-contrast MRI, this noninvasive estimation of Hct, instead of using a population-averaged Hct value, enabled more individual determination of oxygen delivery (DO 2 ), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO 2 ). The inverse correlation of CBF and Hct explained about 80% of between-subject variation of CBF in this relatively uniform cohort of subjects, as expected based on the regulation of DO 2 to maintain constant CMRO 2 . Furthermore, we compared the relationships of visual task-evoked BOLD response with Hct and CBF. We showed that Hct and CBF contributed 22%-33% of variance in BOLD signal and removing the positive correlation with Hct and negative correlation with CBF allowed normalization of BOLD signal with 16%-22% lower variability. The results of this study suggest that adjustment for Hct effects is useful for studies of MRI perfusion and BOLD fMRI. Hum Brain Mapp 39:344-353, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

A Big Five facet analysis of sub-clinical narcissism: understanding boldness in terms of well-known personality traits.

Science.gov (United States)

Furnham, Adrian; Crump, John

2014-08-01

This study aimed to examine a Big Five 'bright-side' analysis of a sub-clinical personality disorder, i.e. narcissism. A total of 6957 British adults completed the NEO-PI-R, which measures the Big Five Personality factors at the domain and the facet level, as well as the Hogan Development Survey (HDS), which has a measure of Narcissism called Bold as one of its dysfunctional interpersonal tendencies. Correlation and regression results confirmed many of the associations between the Big Five domains and facets (NEO-PI-R) and sub-clinical narcissism. The Bold (Narcissism) scale from the HDS was the criterion variable in all analyses. Bold individuals are disagreeable extraverts with very low scores on facet Modesty but moderately high scores on Assertiveness, Competence and Achievement Striving. The study confirmed work using different population groups and different measures. Copyright © 2014 John Wiley & Sons, Ltd.

Effect of hypoxia on BOLD fMRI response and total cerebral blood flow in migraine with aura patients

DEFF Research Database (Denmark)

Arngrim, Nanna; Hougaard, Anders; Schytz, Henrik W

2018-01-01

was measured in the visual cortex ROIs V1-V5. Total cerebral blood flow (CBF) was calculated by measuring the blood velocity in the internal carotid arteries and the basilar artery using phase-contrast mapping (PCM) MRI. Hypoxia induced a greater decrease in BOLD response to visual stimulation in V1-V4 in MA......Experimentally induced hypoxia triggers migraine and aura attacks in patients suffering from migraine with aura (MA). We investigated the blood oxygenation level-dependent (BOLD) signal response to visual stimulation during hypoxia in MA patients and healthy volunteers. In a randomized double......-blind crossover study design, 15 MA patients were allocated to 180 min of normobaric poikilocapnic hypoxia (capillary oxygen saturation 70-75%) or sham (normoxia) on two separate days and 14 healthy volunteers were exposed to hypoxia. The BOLD functional MRI (fMRI) signal response to visual stimulation...

Interictal functional connectivity of human epileptic networks assessed by intracerebral EEG and BOLD signal fluctuations.

Directory of Open Access Journals (Sweden)

Gaelle Bettus

Full Text Available In this study, we aimed to demonstrate whether spontaneous fluctuations in the blood oxygen level dependent (BOLD signal derived from resting state functional magnetic resonance imaging (fMRI reflect spontaneous neuronal activity in pathological brain regions as well as in regions spared by epileptiform discharges. This is a crucial issue as coherent fluctuations of fMRI signals between remote brain areas are now widely used to define functional connectivity in physiology and in pathophysiology. We quantified functional connectivity using non-linear measures of cross-correlation between signals obtained from intracerebral EEG (iEEG and resting-state functional MRI (fMRI in 5 patients suffering from intractable temporal lobe epilepsy (TLE. Functional connectivity was quantified with both modalities in areas exhibiting different electrophysiological states (epileptic and non affected regions during the interictal period. Functional connectivity as measured from the iEEG signal was higher in regions affected by electrical epileptiform abnormalities relative to non-affected areas, whereas an opposite pattern was found for functional connectivity measured from the BOLD signal. Significant negative correlations were found between the functional connectivities of iEEG and BOLD signal when considering all pairs of signals (theta, alpha, beta and broadband and when considering pairs of signals in regions spared by epileptiform discharges (in broadband signal. This suggests differential effects of epileptic phenomena on electrophysiological and hemodynamic signals and/or an alteration of the neurovascular coupling secondary to pathological plasticity in TLE even in regions spared by epileptiform discharges. In addition, indices of directionality calculated from both modalities were consistent showing that the epileptogenic regions exert a significant influence onto the non epileptic areas during the interictal period. This study shows that functional

BOLD fMRI of C-Fiber Mediated Nociceptive Processing in Mouse Brain in Response to Thermal Stimulation of the Forepaws.

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Simone C Bosshard

Full Text Available Functional magnetic resonance imaging (fMRI in rodents enables non-invasive studies of brain function in response to peripheral input or at rest. In this study we describe a thermal stimulation paradigm using infrared laser diodes to apply noxious heat to the forepaw of mice in order to study nociceptive processing. Stimulation at 45 and 46°C led to robust BOLD signal changes in various brain structures including the somatosensory cortices and the thalamus. The BOLD signal amplitude scaled with the temperature applied but not with the area irradiated by the laser beam. To demonstrate the specificity of the paradigm for assessing nociceptive signaling we administered the quaternary lidocaine derivative QX-314 to the forepaws, which due to its positive charge cannot readily cross biological membranes. However, upon activation of TRPV1 channels following the administration of capsaicin the BOLD signal was largely abolished, indicative of a selective block of the C-fiber nociceptors due to QX-314 having entered the cells via the now open TRPV1 channels. This demonstrates that the cerebral BOLD response to thermal noxious paw stimulation is specifically mediated by C-fibers.

Working memory in volunteers and schizophrenics using BOLD fMRI; Das Arbeitsgedaechtnis bei Gesunden und bei Schizophrenen: Untersuchungen mit BOLD-fMRT

Energy Technology Data Exchange (ETDEWEB)

Giesel, F.L. [Deutsches Krebsforschungszentrum (DKFZ) Heidelberg, Abteilung Radiologie (Germany); Deutsches Krebsforschungszentrum (DKFZ), Abteilung Radiologie, Heidelberg (Germany); Hohmann, N. [Deutsches Krebsforschungszentrum (DKFZ) Heidelberg, Abteilung Radiologie (Germany); Psychiatrische Universitaetsklinik Heidelberg, Sektion Gerontopsychiatrie (Germany); Seidl, U.; Kress, K.R.; Schoenknecht, P.; Schroeder, J. [Psychiatrische Universitaetsklinik Heidelberg, Sektion Gerontopsychiatrie (Germany); Kauczor, H.-U.; Essig, M. [Deutsches Krebsforschungszentrum (DKFZ) Heidelberg, Abteilung Radiologie (Germany)

2005-02-01

Functional magnetic resonance imaging uses the blood oxygen level-dependent effect (BOLD MRI) for noninvasive display of cerebral correlatives of cognitive function. The importance for the understanding of physiological and pathological processes is demonstrated by investigations of working memory in schizophrenics and healthy controls. Working memory is involved in processing rather than storage of information and therefore is linked to complex processes such as learning and problem solving. In schizophrenic psychosis, these functions are clearly restricted. Training effects in the working memory task follow an inverse U-shape function, suggesting that cerebral activation reaches a peak before economics of the brain find a more efficient method and activation decreases. (orig.) [German] Die funktionelle Magnetresonanztomographie (fMRT) nutzt den ''blood oxygen level dependent effect'' (BOLD-Effekt) zur nichtinvasiven Darstellung zerebraler Korrelate kognitiver Funktionen. Die Bedeutung dieses Verfahrens fuer das Verstaendnis physiologischer und pathologischer Prozesse wird anhand von Untersuchungen zum Arbeitsgedaechtnis bei Schizophrenen und gesunden Kontrollpersonen verdeutlicht. Das Arbeitsgedaechtnis dient weniger der Speicherung, sondern vielmehr der Verarbeitung von Informationen und ist deshalb in komplexe Prozesse wie Lernen und Problemloesen eingebunden. Im Rahmen schizophrener Psychosen kommt es zu einer deutlichen Einschraenkung dieser Funktionen. Erwartungsgemaess zeigen sich unter Durchfuehrung eines Arbeitsgedaechtnisparadigmas Unterschiede in der zerebralen Aktivitaet, die jedoch bei den Erkrankten unter Therapie prinzipiell reversibel sind. Von Interesse sind auch Trainingseffekte bei Gesunden, wobei eine verminderte Aktivierung nach Training auf eine ''Oekonomisierung'' schliessen laesst. (orig.)

Relationship between BOLD amplitude and pattern classification of orientation-selective activity in the human visual cortex

Science.gov (United States)

Tong, Frank; Harrison, Stephenie A.; Dewey, John A.; Kamitani, Yukiyasu

2012-01-01

Orientation-selective responses can be decoded from fMRI activity patterns in the human visual cortex, using multivariate pattern analysis (MVPA). To what extent do these feature-selective activity patterns depend on the strength and quality of the sensory input, and might the reliability of these activity patterns be predicted by the gross amplitude of the stimulus-driven BOLD response? Observers viewed oriented gratings that varied in luminance contrast (4, 20 or 100%) or spatial frequency (0.25, 1.0 or 4.0 cpd). As predicted, activity patterns in early visual areas led to better discrimination of orientations presented at high than low contrast, with greater effects of contrast found in area V1 than in V3. A second experiment revealed generally better decoding of orientations at low or moderate as compared to high spatial frequencies. Interestingly however, V1 exhibited a relative advantage at discriminating high spatial frequency orientations, consistent with the finer scale of representation in the primary visual cortex. In both experiments, the reliability of these orientation-selective activity patterns was well predicted by the average BOLD amplitude in each region of interest, as indicated by correlation analyses, as well as decoding applied to a simple model of voxel responses to simulated orientation columns. Moreover, individual differences in decoding accuracy could be predicted by the signal-to-noise ratio of an individual's BOLD response. Our results indicate that decoding accuracy can be well predicted by incorporating the amplitude of the BOLD response into simple simulation models of cortical selectivity; such models could prove useful in future applications of fMRI pattern classification. PMID:22917989

Increased BOLD Signals Elicited by High Gamma Auditory Stimulation of the Left Auditory Cortex in Acute State Schizophrenia

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Hironori Kuga, M.D.

2016-10-01

We acquired BOLD responses elicited by click trains of 20, 30, 40 and 80-Hz frequencies from 15 patients with acute episode schizophrenia (AESZ, 14 symptom-severity-matched patients with non-acute episode schizophrenia (NASZ, and 24 healthy controls (HC, assessed via a standard general linear-model-based analysis. The AESZ group showed significantly increased ASSR-BOLD signals to 80-Hz stimuli in the left auditory cortex compared with the HC and NASZ groups. In addition, enhanced 80-Hz ASSR-BOLD signals were associated with more severe auditory hallucination experiences in AESZ participants. The present results indicate that neural over activation occurs during 80-Hz auditory stimulation of the left auditory cortex in individuals with acute state schizophrenia. Given the possible association between abnormal gamma activity and increased glutamate levels, our data may reflect glutamate toxicity in the auditory cortex in the acute state of schizophrenia, which might lead to progressive changes in the left transverse temporal gyrus.

Nonlinear Bayesian Estimation of BOLD Signal under Non-Gaussian Noise

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Ali Fahim Khan

2015-01-01

Full Text Available Modeling the blood oxygenation level dependent (BOLD signal has been a subject of study for over a decade in the neuroimaging community. Inspired from fluid dynamics, the hemodynamic model provides a plausible yet convincing interpretation of the BOLD signal by amalgamating effects of dynamic physiological changes in blood oxygenation, cerebral blood flow and volume. The nonautonomous, nonlinear set of differential equations of the hemodynamic model constitutes the process model while the weighted nonlinear sum of the physiological variables forms the measurement model. Plagued by various noise sources, the time series fMRI measurement data is mostly assumed to be affected by additive Gaussian noise. Though more feasible, the assumption may cause the designed filter to perform poorly if made to work under non-Gaussian environment. In this paper, we present a data assimilation scheme that assumes additive non-Gaussian noise, namely, the e-mixture noise, affecting the measurements. The proposed filter MAGSF and the celebrated EKF are put to test by performing joint optimal Bayesian filtering to estimate both the states and parameters governing the hemodynamic model under non-Gaussian environment. Analyses using both the synthetic and real data reveal superior performance of the MAGSF as compared to EKF.

The role of ecological context and predation risk-stimuli in revealing the true picture about the genetic basis of boldness evolution in fish

DEFF Research Database (Denmark)

Klefoth, Thomas; Skov, Christian; Krause, Jens

2011-01-01

To showcase the importance of genotype × environment interactions and the presence of predation risk in the experimental assessment of boldness in fish, we investigated boldness in terms of feeding behavior and refuge use in two genetically different populations of juvenile carp (Cyprinus carpio)...

BOLD quantified renal pO2 is sensitive to pharmacological challenges in rats.

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Thacker, Jon; Zhang, Jeff L; Franklin, Tammy; Prasad, Pottumarthi

2017-07-01

Blood oxygen level-dependent (BOLD) MRI has been effectively used to monitor changes in renal oxygenation. However, R2* (or T2*) is not specific to blood oxygenation and is dependent on other factors. This study investigates the use of a statistical model that takes these factors into account and maps BOLD MRI measurements to blood pO2. Spin echo and gradient echo images were obtained in six Sprague-Dawley rats and R2 and R2* maps were computed. Measurements were made at baseline, post-nitric oxide synthase inhibitor (L-NAME), and post-furosemide administration. A simulation of each region was performed to map R2' (computed as R2*-R2) to blood pO2. At baseline, blood pO2 in the outer medulla was 30.5 ± 1.2 mmHg and 51.9 ± 5.2 mmHg in the cortex, in agreement with previous invasive studies. Blood pO2 was found to decrease within the outer medulla following L-NAME (P pO2 in the cortex increased following furosemide (P pO2 is sensitive to pharmacological challenges, and baseline pO2 is comparable to literature values. Reporting pO2 instead of R2* could lead to a greater clinical impact of renal BOLD MRI and facilitate the identification of hypoxic regions. Magn Reson Med 78:297-302, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

"To Boldly Go" versus "Last, Best Hope" : The Future of Human Civilization as Depicted in American Science Fiction

OpenAIRE

Glasø, Alexander

2012-01-01

"'To Boldly Go" versus "Last, Best Hope'" examines a total of four American television series from the Star Trek and Babylon 5 franchises, and the portrayal of human civilization in the future. The thesis traces how Star Trek set out "to boldly go" and how Babylon 5 was the "last, best hope" in depicting a coherent, futuristic vision for humanity. The initial chapter focuses on the background of the series and also the ways they differed from one another, while chapter 2 is devoted to the por...

Personality in the cockroach Diploptera punctata: Evidence for stability across developmental stages despite age effects on boldness.

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Stanley, Christina R; Mettke-Hofmann, Claudia; Preziosi, Richard F

2017-01-01

Despite a recent surge in the popularity of animal personality studies and their wide-ranging associations with various aspects of behavioural ecology, our understanding of the development of personality over ontogeny remains poorly understood. Stability over time is a central tenet of personality; ecological pressures experienced by an individual at different life stages may, however, vary considerably, which may have a significant effect on behavioural traits. Invertebrates often go through numerous discrete developmental stages and therefore provide a useful model for such research. Here we test for both differential consistency and age effects upon behavioural traits in the gregarious cockroach Diploptera punctata by testing the same behavioural traits in both juveniles and adults. In our sample, we find consistency in boldness, exploration and sociality within adults whilst only boldness was consistent in juveniles. Both boldness and exploration measures, representative of risk-taking behaviour, show significant consistency across discrete juvenile and adult stages. Age effects are, however, apparent in our data; juveniles are significantly bolder than adults, most likely due to differences in the ecological requirements of these life stages. Size also affects risk-taking behaviour since smaller adults are both bolder and more highly explorative. Whilst a behavioural syndrome linking boldness and exploration is evident in nymphs, this disappears by the adult stage, where links between other behavioural traits become apparent. Our results therefore indicate that differential consistency in personality can be maintained across life stages despite age effects on its magnitude, with links between some personality traits changing over ontogeny, demonstrating plasticity in behavioural syndromes.

Personality in the cockroach Diploptera punctata: Evidence for stability across developmental stages despite age effects on boldness

Science.gov (United States)

Mettke-Hofmann, Claudia; Preziosi, Richard F.

2017-01-01

Despite a recent surge in the popularity of animal personality studies and their wide-ranging associations with various aspects of behavioural ecology, our understanding of the development of personality over ontogeny remains poorly understood. Stability over time is a central tenet of personality; ecological pressures experienced by an individual at different life stages may, however, vary considerably, which may have a significant effect on behavioural traits. Invertebrates often go through numerous discrete developmental stages and therefore provide a useful model for such research. Here we test for both differential consistency and age effects upon behavioural traits in the gregarious cockroach Diploptera punctata by testing the same behavioural traits in both juveniles and adults. In our sample, we find consistency in boldness, exploration and sociality within adults whilst only boldness was consistent in juveniles. Both boldness and exploration measures, representative of risk-taking behaviour, show significant consistency across discrete juvenile and adult stages. Age effects are, however, apparent in our data; juveniles are significantly bolder than adults, most likely due to differences in the ecological requirements of these life stages. Size also affects risk-taking behaviour since smaller adults are both bolder and more highly explorative. Whilst a behavioural syndrome linking boldness and exploration is evident in nymphs, this disappears by the adult stage, where links between other behavioural traits become apparent. Our results therefore indicate that differential consistency in personality can be maintained across life stages despite age effects on its magnitude, with links between some personality traits changing over ontogeny, demonstrating plasticity in behavioural syndromes. PMID:28489864

Resting bold fMRI differentiates dementia with Lewy bodies vs Alzheimer disease

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Price, J.L.; Yan, Z.; Morris, J.C.; Sheline, Y.I.

2011-01-01

Objective: Clinicopathologic phenotypes of dementia with Lewy bodies (DLB) and Alzheimer disease (AD) often overlap, making discrimination difficult. We performed resting state blood oxygen level–dependent (BOLD) functional connectivity MRI (fcMRI) to determine whether there were differences between AD and DLB. Methods: Participants (n = 88) enrolled in a longitudinal study of memory and aging underwent 3-T fcMRI. Clinical diagnoses of probable DLB (n = 15) were made according to published criteria. Cognitively normal control participants (n = 38) were selected for the absence of cerebral amyloid burden as imaged with Pittsburgh compound B (PiB). Probable AD cases (n = 35) met published criteria and had appreciable amyloid deposits with PiB imaging. Functional images were collected using a gradient spin-echo sequence sensitive to BOLD contrast (T2* weighting). Correlation maps selected a seed region in the combined bilateral precuneus. Results: Participants with DLB had a functional connectivity pattern for the precuneus seed region that was distinct from AD; both the DLB and AD groups had functional connectivity patterns that differed from the cognitively normal group. In the DLB group, we found increased connectivity between the precuneus and regions in the dorsal attention network and the putamen. In contrast, we found decreased connectivity between the precuneus and other task-negative default regions and visual cortices. There was also a reversal of connectivity in the right hippocampus. Conclusions: Changes in functional connectivity in DLB indicate patterns of activation that are distinct from those seen in AD and may improve discrimination of DLB from AD and cognitively normal individuals. Since patterns of connectivity differ between AD and DLB groups, measurements of BOLD functional connectivity can shed further light on neuroanatomic connections that distinguish DLB from AD. PMID:21525427

A statistical approach for segregating cognitive task stages from multivariate fMRI BOLD time series

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Charmaine eDemanuele

2015-10-01

Full Text Available Multivariate pattern analysis can reveal new information from neuroimaging data to illuminate human cognition and its disturbances. Here, we develop a methodological approach, based on multivariate statistical/machine learning and time series analysis, to discern cognitive processing stages from fMRI blood oxygenation level dependent (BOLD time series. We apply this method to data recorded from a group of healthy adults whilst performing a virtual reality version of the delayed win-shift radial arm maze task. This task has been frequently used to study working memory and decision making in rodents. Using linear classifiers and multivariate test statistics in conjunction with time series bootstraps, we show that different cognitive stages of the task, as defined by the experimenter, namely, the encoding/retrieval, choice, reward and delay stages, can be statistically discriminated from the BOLD time series in brain areas relevant for decision making and working memory. Discrimination of these task stages was significantly reduced during poor behavioral performance in dorsolateral prefrontal cortex (DLPFC, but not in the primary visual cortex (V1. Experimenter-defined dissection of time series into class labels based on task structure was confirmed by an unsupervised, bottom-up approach based on Hidden Markov Models. Furthermore, we show that different groupings of recorded time points into cognitive event classes can be used to test hypotheses about the specific cognitive role of a given brain region during task execution. We found that whilst the DLPFC strongly differentiated between task stages associated with different memory loads, but not between different visual-spatial aspects, the reverse was true for V1. Our methodology illustrates how different aspects of cognitive information processing during one and the same task can be separated and attributed to specific brain regions based on information contained in multivariate patterns of voxel

Intraindividual variability of boldness is repeatable across contexts in a wild lizard.

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Laura Highcock

Full Text Available Animals do not behave in exactly the same way when repeatedly tested in the same context or situation, even once systematic variation, such as habituation, has been controlled for. This unpredictability is called intraindividual variability (IIV and has been little studied in animals. Here we investigated how IIV in boldness (estimated by flight initiation distances changed across two seasons--the dry, non-breeding season and the wet, breeding season--in a wild population of the Namibian rock agama, Agama planiceps. We found significant differences in IIV both between individuals and seasons, and IIV was higher in the wet season, suggesting plasticity in IIV. Further, IIV was highly repeatable (r = 0.61 between seasons and we found strong negative correlations between consistent individual differences in flight initiation distances, i.e. their boldness, and individuals' IIVs. We suggest that to understand personality in animals, researchers should generate a personality 'profile' that includes not only the relative level of a trait (i.e. its personality, but also its plasticity and variability under natural conditions.

Visual BOLD Response in Late Blind Subjects with Argus II Retinal Prosthesis.

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E Castaldi

2016-10-01

Full Text Available Retinal prosthesis technologies require that the visual system downstream of the retinal circuitry be capable of transmitting and elaborating visual signals. We studied the capability of plastic remodeling in late blind subjects implanted with the Argus II Retinal Prosthesis with psychophysics and functional MRI (fMRI. After surgery, six out of seven retinitis pigmentosa (RP blind subjects were able to detect high-contrast stimuli using the prosthetic implant. However, direction discrimination to contrast modulated stimuli remained at chance level in all of them. No subject showed any improvement of contrast sensitivity in either eye when not using the Argus II. Before the implant, the Blood Oxygenation Level Dependent (BOLD activity in V1 and the lateral geniculate nucleus (LGN was very weak or absent. Surprisingly, after prolonged use of Argus II, BOLD responses to visual input were enhanced. This is, to our knowledge, the first study tracking the neural changes of visual areas in patients after retinal implant, revealing a capacity to respond to restored visual input even after years of deprivation.

Dual-time-point O-(2-[{sup 18}F]fluoroethyl)-L-tyrosine PET for grading of cerebral gliomas

Energy Technology Data Exchange (ETDEWEB)

Lohmann, Philipp; Herzog, Hans; Rota Kops, Elena; Stoffels, Gabriele; Judov, Natalie; Filss, Christian; Tellmann, Lutz [Forschungszentrum Juelich, Institute of Neuroscience and Medicine, Juelich (Germany); Galldiks, Norbert [Forschungszentrum Juelich, Institute of Neuroscience and Medicine, Juelich (Germany); University of Cologne, Department of Neurology, Cologne (Germany); Weiss, Carolin [University of Cologne, Department of Neurosurgery, Cologne (Germany); Sabel, Michael [Heinrich-Heine University, Department of Neurosurgery, Duesseldorf (Germany); Coenen, Heinz Hubert [Forschungszentrum Juelich, Institute of Neuroscience and Medicine, Juelich (Germany); Juelich-Aachen Research Alliance (JARA) - Section JARA-Brain, Juelich (Germany); Shah, Nadim Jon [Forschungszentrum Juelich, Institute of Neuroscience and Medicine, Juelich (Germany); Juelich-Aachen Research Alliance (JARA) - Section JARA-Brain, Juelich (Germany); RWTH Aachen University Hospital, Department of Neurology, Aachen (Germany); Langen, Karl-Josef [Forschungszentrum Juelich, Institute of Neuroscience and Medicine, Juelich (Germany); RWTH Aachen University Hospital, Department of Nuclear Medicine, Aachen (Germany); Juelich-Aachen Research Alliance (JARA) - Section JARA-Brain, Juelich (Germany)

2015-10-15

We aimed to evaluate the diagnostic potential of dual-time-point imaging with positron emission tomography (PET) using O-(2-[{sup 18}F]fluoroethyl)-L-tyrosine ({sup 18}F-FET) for non-invasive grading of cerebral gliomas compared with a dynamic approach. Thirty-six patients with histologically confirmed cerebral gliomas (21 primary, 15 recurrent; 24 high-grade, 12 low-grade) underwent dynamic PET from 0 to 50 min post-injection (p.i.) of {sup 18}F-FET, and additionally from 70 to 90 min p.i. Mean tumour-to-brain ratios (TBR{sub mean}) of {sup 18}F-FET uptake were determined in early (20-40 min p.i.) and late (70-90 min p.i.) examinations. Time-activity curves (TAC) of the tumours from 0 to 50 min after injection were assigned to different patterns. The diagnostic accuracy of changes of {sup 18}F-FET uptake between early and late examinations for tumour grading was compared to that of curve pattern analysis from 0 to 50 min p.i. of {sup 18}F-FET. The diagnostic accuracy of changes of the TBR{sub mean} of {sup 18}F-FET PET uptake between early and late examinations for the identification of HGG was 81 % (sensitivity 83 %; specificity 75 %; cutoff - 8 %; p < 0.001), and 83 % for curve pattern analysis (sensitivity 88 %; specificity 75 %; p < 0.001). Dual-time-point imaging of {sup 18}F-FET uptake in gliomas achieves diagnostic accuracy for tumour grading that is similar to the more time-consuming dynamic data acquisition protocol. (orig.)

Resting State BOLD Variability in Alzheimer’s Disease: A Marker of Cognitive Decline or Cerebrovascular Status?

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Vanessa Scarapicchia

2018-02-01

Full Text Available Background: Alzheimer’s disease (AD is a neurodegenerative disorder that may benefit from early diagnosis and intervention. Therefore, there is a need to identify early biomarkers of AD using non-invasive techniques such as functional magnetic resonance imaging (fMRI. Recently, novel approaches to the analysis of resting-state fMRI data have been developed that focus on the moment-to-moment variability in the blood oxygen level dependent (BOLD signal. The objective of the current study was to investigate BOLD variability as a novel early biomarker of AD and its associated psychophysiological correlates.Method: Data were obtained from the Alzheimer’s Disease Neuroimaging Initiative (ADNI 2 database from 19 participants with AD and 19 similarly aged controls. For each participant, a map of BOLD signal variability (SDBOLD was computed as the standard deviation of the BOLD timeseries at each voxel. Group comparisons were performed to examine global differences in resting state SDBOLD in AD versus healthy controls. Correlations were then examined between participant SDBOLD maps and (1 ADNI-derived composite scores of memory and executive function and (2 neuroimaging markers of cerebrovascular status.Results: Between-group comparisons revealed significant (p < 0.05 increases in SDBOLD in patients with AD relative to healthy controls in right-lateralized frontal regions. Lower memory scores and higher WMH burden were associated with greater SDBOLD in the healthy control group (p < 0.1, but not individuals with AD.Conclusion: The current study provides proof of concept of a novel resting state fMRI analysis technique that is non-invasive, easily accessible, and clinically compatible. To further explore the potential of SDBOLD as a biomarker of AD, additional studies in larger, longitudinal samples are needed to better understand the changes in SDBOLD that characterize earlier stages of disease progression and their underlying psychophysiological

Spatiotopic coding of BOLD signal in human visual cortex depends on spatial attention.

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Sofia Crespi

Full Text Available The neural substrate of the phenomenological experience of a stable visual world remains obscure. One possible mechanism would be to construct spatiotopic neural maps where the response is selective to the position of the stimulus in external space, rather than to retinal eccentricities, but evidence for these maps has been inconsistent. Here we show, with fMRI, that when human subjects perform concomitantly a demanding attentive task on stimuli displayed at the fovea, BOLD responses evoked by moving stimuli irrelevant to the task were mostly tuned in retinotopic coordinates. However, under more unconstrained conditions, where subjects could attend easily to the motion stimuli, BOLD responses were tuned not in retinal but in external coordinates (spatiotopic selectivity in many visual areas, including MT, MST, LO and V6, agreeing with our previous fMRI study. These results indicate that spatial attention may play an important role in mediating spatiotopic selectivity.

Dorsal root ganglion stimulation attenuates the BOLD signal response to noxious sensory input in specific brain regions: Insights into a possible mechanism for analgesia.

Science.gov (United States)

Pawela, Christopher P; Kramer, Jeffery M; Hogan, Quinn H

2017-02-15

Targeted dorsal root ganglion (DRG) electrical stimulation (i.e. ganglionic field stimulation - GFS) is an emerging therapeutic approach to alleviate chronic pain. Here we describe blood oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI) responses to noxious hind-limb stimulation in a rat model that replicates clinical GFS using an electrode implanted adjacent to the DRG. Acute noxious sensory stimulation in the absence of GFS caused robust BOLD fMRI response in brain regions previously associated with sensory and pain-related response, such as primary/secondary somatosensory cortex, retrosplenial granular cortex, thalamus, caudate putamen, nucleus accumbens, globus pallidus, and amygdala. These regions differentially demonstrated either positive or negative correlation to the acute noxious stimulation paradigm, in agreement with previous rat fMRI studies. Therapeutic-level GFS significantly attenuated the global BOLD response to noxious stimulation in these regions. This BOLD signal attenuation persisted for 20minutes after the GFS was discontinued. Control experiments in sham-operated animals showed that the attenuation was not due to the effect of repetitive noxious stimulation. Additional control experiments also revealed minimal BOLD fMRI response to GFS at therapeutic intensity when presented in a standard block-design paradigm. High intensity GFS produced a BOLD signal map similar to acute noxious stimulation when presented in a block-design. These findings are the first to identify the specific brain region responses to neuromodulation at the DRG level and suggest possible mechanisms for GFS-induced treatment of chronic pain. Copyright © 2016 Elsevier Inc. All rights reserved.

A NO way to BOLD?

DEFF Research Database (Denmark)

Aamand, Rasmus; Dalsgaard, Thomas; Ho, Yi Ching Lynn

2013-01-01

Neurovascular coupling links neuronal activity to vasodilation. Nitric oxide (NO) is a potent vasodilator, and in neurovascular coupling NO production from NO synthases plays an important role. However, another pathway for NO production also exists, namely the nitrate-nitrite-NO pathway. On this ......Neurovascular coupling links neuronal activity to vasodilation. Nitric oxide (NO) is a potent vasodilator, and in neurovascular coupling NO production from NO synthases plays an important role. However, another pathway for NO production also exists, namely the nitrate-nitrite-NO pathway...... to stimuli. A faster and smaller BOLD response, with less variation across local cortex, is consistent with an enhanced hemodynamic coupling during elevated nitrate intake. These findings suggest that dietary patterns, via the nitrate-nitrite-NO pathway, may be a potential way to affect key properties....... On this basis, we hypothesized that dietary nitrate (NO3-) could influence the brain's hemodynamic response to neuronal stimulation. In the present study, 20 healthy male participants were given either sodium nitrate (NaNO3) or sodium chloride (NaCl) (saline placebo) in a crossover study and were shown visual...

Hypoxia in Prostate Cancer: Correlation of BOLD-MRI With Pimonidazole Immunohistochemistry-Initial Observations

International Nuclear Information System (INIS)

Hoskin, Peter J.; Carnell, Dawn M.; Taylor, N. Jane; Smith, Rowena E.; Stirling, J. James; Daley, Frances M.; Saunders, Michele I.; Bentzen, Soren M.; Collins, David J.; D'Arcy, James A.; Padhani, Anwar P.

2007-01-01

Purpose: To investigate the ability of blood oxygen level-dependent (BOLD) MRI to depict clinically significant prostate tumor hypoxia. Methods and Materials: Thirty-three patients with prostate carcinoma undergoing radical prostatectomy were studied preoperatively, using gradient echo sequences without and with contrast medium enhancement, to map relative tissue oxygenation according to relaxivity rates and relative blood volume (rBV). Pimonidazole was administered preoperatively, and whole-mount sections of selected tumor-bearing slices were stained for pimonidazole fixation and tumor and nontumor localization. Histologic and imaging parameters were independently mapped onto patient prostate outlines. Using 5-mm grids, 861 nontumor grid locations were compared with 237 tumor grids (with >50% tumor per location) using contingency table analysis with respect to the ability of imaging to predict pimonidazole staining. Results: Twenty patients completed the imaging and histologic protocols. Pimonidazole staining was found in 33% of nontumor and in 70% of tumor grids. The sensitivity of the MR relaxivity parameter R 2 * in depicting tumor hypoxia was high (88%), improving with the addition of low rBV information (95%) without changing specificity (36% and 29%, respectively). High R 2 * increased the positive predictive value for hypoxia by 6% (70% to 76%); conversely, low R 2 * decreased the likelihood of hypoxia being present by 26% (70% to 44%) and by 41% (71% to 30%) when combined with rBV information. Conclusion: R 2 * maps from BOLD-MRI have high sensitivity but low specificity for defining intraprostatic tumor hypoxia. This together with the negative predictive value of 70% when combined with blood volume information makes BOLD-MRI a potential noninvasive technique for mapping prostatic tumor hypoxia

Dictionary-driven Ischemia Detection from Cardiac Phase-Resolved Myocardial BOLD MRI at Rest

Science.gov (United States)

Bevilacqua, Marco; Dharmakumar, Rohan; Tsaftaris, Sotirios A.

2016-01-01

Cardiac Phase-resolved Blood-Oxygen-Level Dependent (CP–BOLD) MRI provides a unique opportunity to image an ongoing ischemia at rest. However, it requires post-processing to evaluate the extent of ischemia. To address this, here we propose an unsupervised ischemia detection (UID) method which relies on the inherent spatio-temporal correlation between oxygenation and wall motion to formalize a joint learning and detection problem based on dictionary decomposition. Considering input data of a single subject, it treats ischemia as an anomaly and iteratively learns dictionaries to represent only normal observations (corresponding to myocardial territories remote to ischemia). Anomaly detection is based on a modified version of One-class Support Vector Machines (OCSVM) to regulate directly the margins by incorporating the dictionary-based representation errors. A measure of ischemic extent (IE) is estimated, reflecting the relative portion of the myocardium affected by ischemia. For visualization purposes an ischemia likelihood map is created by estimating posterior probabilities from the OCSVM outputs, thus obtaining how likely the classification is correct. UID is evaluated on synthetic data and in a 2D CP–BOLD data set from a canine experimental model emulating acute coronary syndromes. Comparing early ischemic territories identified with UID against infarct territories (after several hours of ischemia), we find that IE, as measured by UID, is highly correlated (Pearson’s r = 0.84) w.r.t. infarct size. When advances in automated registration and segmentation of CP–BOLD images and full coverage 3D acquisitions become available, we hope that this method can enable pixel-level assessment of ischemia with this truly non-invasive imaging technique. PMID:26292338

Driving innovation through big open linked data (BOLD) : Exploring antecedents using interpretive structural modelling

NARCIS (Netherlands)

Dwivedi, Yogesh K.; Janssen, M.F.W.H.A.; Slade, Emma L.; Rana, Nripendra P.; Weerakkody, Vishanth; Millard, Jeremy; Hidders, Jan; Snijders, D.

2016-01-01

Innovation is vital to find new solutions to problems, increase quality, and improve profitability. Big open linked data (BOLD) is a fledgling and rapidly evolving field that creates new opportunities for innovation. However, none of the existing literature has yet considered the

Negative BOLD response and serotonin concentration within rostral subgenual portion of the anterior cingulate cortex for long-allele carriers during perceptual processing of emotional tasks

Science.gov (United States)

Hadi, Shamil M.; Siadat, Mohamad R.; Babajani-Feremi, Abbas

2012-03-01

We investigated the effect of synaptic serotonin concentration on hemodynamic responses. The stimuli paradigm involved the presentation of fearful and threatening facial expressions to a set of 24 subjects who were either5HTTLPR long- or short-allele carriers (12 of each type in each group). The BOLD signals of the rACC from subjects of each group were averaged to increase the signal-to-noise ratio. We used a Bayesian approach to estimate the parameters of the underlying hemodynamic model. Our results, during this perceptual processing of emotional task, showed a negative BOLD signal in the rACC in the subjects with long-alleles. In contrast, the subjects with short-alleles showed positive BOLD signals in the rACC. These results suggest that high synaptic serotonin concentration in the rACC inhibits neuronal activity in a fashion similar to GABA, and a consequent negative BOLD signal ensues.

Visual, Auditory, and Cross Modal Sensory Processing in Adults with Autism: An EEG Power and BOLD fMRI Investigation

Science.gov (United States)

Hames, Elizabeth’ C.; Murphy, Brandi; Rajmohan, Ravi; Anderson, Ronald C.; Baker, Mary; Zupancic, Stephen; O’Boyle, Michael; Richman, David

2016-01-01

Electroencephalography (EEG) and blood oxygen level dependent functional magnetic resonance imagining (BOLD fMRI) assessed the neurocorrelates of sensory processing of visual and auditory stimuli in 11 adults with autism (ASD) and 10 neurotypical (NT) controls between the ages of 20–28. We hypothesized that ASD performance on combined audiovisual trials would be less accurate with observable decreased EEG power across frontal, temporal, and occipital channels and decreased BOLD fMRI activity in these same regions; reflecting deficits in key sensory processing areas. Analysis focused on EEG power, BOLD fMRI, and accuracy. Lower EEG beta power and lower left auditory cortex fMRI activity were seen in ASD compared to NT when they were presented with auditory stimuli as demonstrated by contrasting the activity from the second presentation of an auditory stimulus in an all auditory block vs. the second presentation of a visual stimulus in an all visual block (AA2-VV2).We conclude that in ASD, combined audiovisual processing is more similar than unimodal processing to NTs. PMID:27148020

Visual, Auditory, and Cross Modal Sensory Processing in Adults with Autism:An EEG Power and BOLD fMRI Investigation

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Elizabeth C Hames

2016-04-01

Full Text Available Electroencephalography (EEG and Blood Oxygen Level Dependent Functional Magnetic Resonance Imagining (BOLD fMRI assessed the neurocorrelates of sensory processing of visual and auditory stimuli in 11 adults with autism (ASD and 10 neurotypical (NT controls between the ages of 20-28. We hypothesized that ASD performance on combined audiovisual trials would be less accurate with observable decreased EEG power across frontal, temporal, and occipital channels and decreased BOLD fMRI activity in these same regions; reflecting deficits in key sensory processing areas. Analysis focused on EEG power, BOLD fMRI, and accuracy. Lower EEG beta power and lower left auditory cortex fMRI activity were seen in ASD compared to NT when they were presented with auditory stimuli as demonstrated by contrasting the activity from the second presentation of an auditory stimulus in an all auditory block versus the second presentation of a visual stimulus in an all visual block (AA2­VV2. We conclude that in ASD, combined audiovisual processing is more similar than unimodal processing to NTs.

Effects of glyceryl trinitrate and calcitonin-gene-related peptide on BOLD signal and arterial diameter –methodological studies by fMRI and MRA

DEFF Research Database (Denmark)

Asghar, Mohammed Sohail; Ashina, Messoud

2013-01-01

Over the last decades MRI has proved to be very useful in the field of drug development and discovery. Pharmacological MRI (phMRI) explores the interaction between brain physiology, neuronal activity and drugs[1]. The BOLD-signal is an indirect method to investigate brain activity by way...... of measuring task-related hemodynamic changes. Pharmacological substances that induce hemodynamic changes can therefore potentially alter the BOLD-signal that in turn falsely can be interpreted as changes in neuronal activity. It is therefore important to characterize possible effects of a pharmacological...... substance on the BOLD-response per see before that substance can be used in an fMRI experiment. Furthermore MR-angiography is useful in determining the vascular site-of-action of vasoactive substances....

Approaches to brain stress testing: BOLD magnetic resonance imaging with computer-controlled delivery of carbon dioxide.

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W Alan C Mutch

Full Text Available BACKGROUND: An impaired vascular response in the brain regionally may indicate reduced vascular reserve and vulnerability to ischemic injury. Changing the carbon dioxide (CO(2 tension in arterial blood is commonly used as a cerebral vasoactive stimulus to assess the cerebral vascular response, changing cerebral blood flow (CBF by up to 5-11 percent/mmHg in normal adults. Here we describe two approaches to generating the CO(2 challenge using a computer-controlled gas blender to administer: i a square wave change in CO(2 and, ii a ramp stimulus, consisting of a continuously graded change in CO(2 over a range. Responses were assessed regionally by blood oxygen level dependent (BOLD magnetic resonance imaging (MRI. METHODOLOGY/PRINCIPAL FINDINGS: We studied 8 patients with known cerebrovascular disease (carotid stenosis or occlusion and 2 healthy subjects. The square wave stimulus was used to study the dynamics of the vascular response, while the ramp stimulus assessed the steady-state response to CO(2. Cerebrovascular reactivity (CVR maps were registered by color coding and overlaid on the anatomical scans generated with 3 Tesla MRI to assess the corresponding BOLD signal change/mmHg change in CO(2, voxel-by-voxel. Using a fractal temporal approach, detrended fluctuation analysis (DFA maps of the processed raw BOLD signal per voxel over the same CO(2 range were generated. Regions of BOLD signal decrease with increased CO(2 (coded blue were seen in all of these high-risk patients, indicating regions of impaired CVR. All patients also demonstrated regions of altered signal structure on DFA maps (Hurst exponents less than 0.5; coded blue indicative of anti-persistent noise. While 'blue' CVR maps remained essentially stable over the time of analysis, 'blue' DFA maps improved. CONCLUSIONS/SIGNIFICANCE: This combined dual stimulus and dual analysis approach may be complementary in identifying vulnerable brain regions and thus constitute a regional as

The value of dual time point 18F-FDG PET imaging for the differentiation between malignant and benign lesions

International Nuclear Information System (INIS)

Lan, X.-L.; Zhang, Y.-X.; Wu, Z.-J.; Jia, Q.; Wei, H.; Gao, Z.-R.

2008-01-01

Aim: To assess the clinical value of dual time point 2-[ 18 F]-fluoro-2-deoxy-D-glucose positron emission tomography ( 18 F-FDG PET) imaging for the differentiation between malignant and benign lesions. Materials and methods: Ninety-six patients (28 patients with primary lung cancer, 18 patients with digestive system carcinoma, 13 patients with other malignant tumours, and 37 patients with benign lesions) underwent FDG-PET/CT at two time points: examination 1 at 45-55 min and examination 2 at 160 ± 24 (150-180) min after the intravenous injection of 233 ± 52 (185-370) MBq 18 F-FDG. Reconstructed images were evaluated qualitatively and quantitatively. The maximum standardized uptake values (SUVmax) of the lesions were calculated for both time points. An increase was considered to have occurred if the SUVs at examination 2 had increased by >10% as compared with those at the examination 1. Results: The lesions in 24 of 28 (86%) patients with primary lung cancer had an SUVmax ≥2.5 at examination 1. Of these, SUVmax values increased in 23 patients, but had not changed in one patient, at examination 2. The lesions in the other four patients with primary lung tumour had SUVmax values between 1.5 and 2.5 at examination 1, which were considered as suspected positive, increased SUVmax values were observed in three of these patients at examination 2. The malignant lesions in 17 of 18 patients with digestive system carcinoma showed SUVmax values ≥2.5 and only one patient had an SUVmax value 18 F-FDG PET imaging is an important noninvasive method for the differentiation of malignant and nonmalignant lesions

Determination of relative CMRO2 from CBF and BOLD changes: significant increase of oxygen consumption rate during visual stimulation

DEFF Research Database (Denmark)

Kim, S.G.; Rostrup, Egill; Larsson, H.B.

1999-01-01

signal changes were measured simultaneously using the flow-sensitive alternating inversion recovery (FAIR) technique. During hypercapnia established by an end-tidal CO2 increase of 1.46 kPa, CBF in the visual cortex increased by 47.3 +/- 17.3% (mean +/- SD; n = 9), and deltaR2* was -0.478 +/- 0.147 sec......The blood oxygenation level-dependent (BOLD) effect in functional magnetic resonance imaging depends on at least partial uncoupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) changes. By measuring CBF and BOLD simultaneously, the relative change in CMRO2 can...

Non-linear Relationship between BOLD Activation and Amplitude of Beta Oscillations in the Supplementary Motor Area during Rhythmic Finger Tapping and Internal Timing

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Gompf, Florian; Pflug, Anja; Laufs, Helmut; Kell, Christian A.

2017-01-01

Functional imaging studies using BOLD contrasts have consistently reported activation of the supplementary motor area (SMA) both during motor and internal timing tasks. Opposing findings, however, have been shown for the modulation of beta oscillations in the SMA. While movement suppresses beta oscillations in the SMA, motor and non-motor tasks that rely on internal timing increase the amplitude of beta oscillations in the SMA. These independent observations suggest that the relationship between beta oscillations and BOLD activation is more complex than previously thought. Here we set out to investigate this rapport by examining beta oscillations in the SMA during movement with varying degrees of internal timing demands. In a simultaneous EEG-fMRI experiment, 20 healthy right-handed subjects performed an auditory-paced finger-tapping task. Internal timing was operationalized by including conditions with taps on every fourth auditory beat, which necessitates generation of a slow internal rhythm, while tapping to every auditory beat reflected simple auditory-motor synchronization. In the SMA, BOLD activity increased and power in both the low and the high beta band decreased expectedly during each condition compared to baseline. Internal timing was associated with a reduced desynchronization of low beta oscillations compared to conditions without internal timing demands. In parallel with this relative beta power increase, internal timing activated the SMA more strongly in terms of BOLD. This documents a task-dependent non-linear relationship between BOLD and beta-oscillations in the SMA. We discuss different roles of beta synchronization and desynchronization in active processing within the same cortical region. PMID:29249950

Non-linear Relationship between BOLD Activation and Amplitude of Beta Oscillations in the Supplementary Motor Area during Rhythmic Finger Tapping and Internal Timing.

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Gompf, Florian; Pflug, Anja; Laufs, Helmut; Kell, Christian A

2017-01-01

Functional imaging studies using BOLD contrasts have consistently reported activation of the supplementary motor area (SMA) both during motor and internal timing tasks. Opposing findings, however, have been shown for the modulation of beta oscillations in the SMA. While movement suppresses beta oscillations in the SMA, motor and non-motor tasks that rely on internal timing increase the amplitude of beta oscillations in the SMA. These independent observations suggest that the relationship between beta oscillations and BOLD activation is more complex than previously thought. Here we set out to investigate this rapport by examining beta oscillations in the SMA during movement with varying degrees of internal timing demands. In a simultaneous EEG-fMRI experiment, 20 healthy right-handed subjects performed an auditory-paced finger-tapping task. Internal timing was operationalized by including conditions with taps on every fourth auditory beat, which necessitates generation of a slow internal rhythm, while tapping to every auditory beat reflected simple auditory-motor synchronization. In the SMA, BOLD activity increased and power in both the low and the high beta band decreased expectedly during each condition compared to baseline. Internal timing was associated with a reduced desynchronization of low beta oscillations compared to conditions without internal timing demands. In parallel with this relative beta power increase, internal timing activated the SMA more strongly in terms of BOLD. This documents a task-dependent non-linear relationship between BOLD and beta-oscillations in the SMA. We discuss different roles of beta synchronization and desynchronization in active processing within the same cortical region.

SU-E-J-223: A BOLD Contrast Imaging Sequence to Evaluate Oxygenation Changes Due to Breath Holding for Breast Radiotherapy: A Pilot Study

International Nuclear Information System (INIS)

Adamson, J; Chang, Z; Cai, J; Palta, M; Horton, J; Yin, F; Blitzblau, R

2015-01-01

Purpose: To develop a robust MRI sequence to measure BOLD breath hold induced contrast in context of breast radiotherapy. Methods: Two sequences were selected from prior studies as candidates to measure BOLD contrast attributable to breath holding within the breast: (1) T2* based Gradient Echo EPI (TR/TE = 500/41ms, flip angle = 60°), and (2) T2 based Single Shot Fast Spin Echo (SSFSE) (TR/TE = 3000/60ms). We enrolled ten women post-lumpectomy for breast cancer who were undergoing treatment planning for whole breast radiotherapy. Each session utilized a 1.5T GE MRI and 4 channel breast coil with the subject immobilized prone on a custom board. For each sequence, 1–3 planes of the lumpectomy breast were imaged continuously during a background measurement (1min) and intermittent breath holds (20–40s per breath hold, 3–5 holds per sequence). BOLD contrast was quantified as correlation of changes in per-pixel intensity with the breath hold schedule convolved with a hemodynamic response function. Subtle motion was corrected using a deformable registration algorithm. Correlation with breath-holding was considered significant if p<0.001. Results: The percentage of the breast ROI with positive BOLD contrast measured by the two sequences were in agreement with a correlation coefficient of R=0.72 (p=0.02). While both sequences demonstrated areas with strong BOLD response, the response was more systematic throughout the breast for the SSFSE (T2) sequence (% breast with response in the same direction: 51.2%±0.7% for T2* vs. 68.1%±16% for T2). In addition, the T2 sequence was less prone to magnetic susceptibility artifacts, especially in presence of seroma, and provided a more robust image with little distortion or artifacts. Conclusion: A T2 SSFSE sequence shows promise for measuring BOLD contrast in the context of breast radiotherapy utilizing a breath hold technique. Further study in a larger patient cohort is warranted to better refine this novel technique

SU-E-J-223: A BOLD Contrast Imaging Sequence to Evaluate Oxygenation Changes Due to Breath Holding for Breast Radiotherapy: A Pilot Study

Energy Technology Data Exchange (ETDEWEB)

Adamson, J; Chang, Z; Cai, J; Palta, M; Horton, J; Yin, F; Blitzblau, R [Duke University Medical Center, Durham, NC (United States)

2015-06-15

Purpose: To develop a robust MRI sequence to measure BOLD breath hold induced contrast in context of breast radiotherapy. Methods: Two sequences were selected from prior studies as candidates to measure BOLD contrast attributable to breath holding within the breast: (1) T2* based Gradient Echo EPI (TR/TE = 500/41ms, flip angle = 60°), and (2) T2 based Single Shot Fast Spin Echo (SSFSE) (TR/TE = 3000/60ms). We enrolled ten women post-lumpectomy for breast cancer who were undergoing treatment planning for whole breast radiotherapy. Each session utilized a 1.5T GE MRI and 4 channel breast coil with the subject immobilized prone on a custom board. For each sequence, 1–3 planes of the lumpectomy breast were imaged continuously during a background measurement (1min) and intermittent breath holds (20–40s per breath hold, 3–5 holds per sequence). BOLD contrast was quantified as correlation of changes in per-pixel intensity with the breath hold schedule convolved with a hemodynamic response function. Subtle motion was corrected using a deformable registration algorithm. Correlation with breath-holding was considered significant if p<0.001. Results: The percentage of the breast ROI with positive BOLD contrast measured by the two sequences were in agreement with a correlation coefficient of R=0.72 (p=0.02). While both sequences demonstrated areas with strong BOLD response, the response was more systematic throughout the breast for the SSFSE (T2) sequence (% breast with response in the same direction: 51.2%±0.7% for T2* vs. 68.1%±16% for T2). In addition, the T2 sequence was less prone to magnetic susceptibility artifacts, especially in presence of seroma, and provided a more robust image with little distortion or artifacts. Conclusion: A T2 SSFSE sequence shows promise for measuring BOLD contrast in the context of breast radiotherapy utilizing a breath hold technique. Further study in a larger patient cohort is warranted to better refine this novel technique.

Neural Correlates of Facial Mimicry: Simultaneous Measurements of EMG and BOLD Responses during Perception of Dynamic Compared to Static Facial Expressions

Science.gov (United States)

Rymarczyk, Krystyna; Żurawski, Łukasz; Jankowiak-Siuda, Kamila; Szatkowska, Iwona

2018-01-01

Facial mimicry (FM) is an automatic response to imitate the facial expressions of others. However, neural correlates of the phenomenon are as yet not well established. We investigated this issue using simultaneously recorded EMG and BOLD signals during perception of dynamic and static emotional facial expressions of happiness and anger. During display presentations, BOLD signals and zygomaticus major (ZM), corrugator supercilii (CS) and orbicularis oculi (OO) EMG responses were recorded simultaneously from 46 healthy individuals. Subjects reacted spontaneously to happy facial expressions with increased EMG activity in ZM and OO muscles and decreased CS activity, which was interpreted as FM. Facial muscle responses correlated with BOLD activity in regions associated with motor simulation of facial expressions [i.e., inferior frontal gyrus, a classical Mirror Neuron System (MNS)]. Further, we also found correlations for regions associated with emotional processing (i.e., insula, part of the extended MNS). It is concluded that FM involves both motor and emotional brain structures, especially during perception of natural emotional expressions. PMID:29467691

An Experimental Study of Effects on Schoolchildren of Exposure to Point-of-Sale Cigarette Advertising and Pack Displays

Science.gov (United States)

Wakefield, Melanie; Germain, Daniella; Durkin, Sarah; Henriksen, Lisa

2006-01-01

By creating a sense of familiarity with tobacco, cigarette advertising and bold packaging displays in stores where children often visit may help to pre-dispose them to smoking. A total of 605 ninth-grade students were randomly allocated to view a photograph of a typical convenience store point-of-sale which had been digitally manipulated to show…

Computing moment to moment BOLD activation for real-time neurofeedback

Science.gov (United States)

Hinds, Oliver; Ghosh, Satrajit; Thompson, Todd W.; Yoo, Julie J.; Whitfield-Gabrieli, Susan; Triantafyllou, Christina; Gabrieli, John D.E.

2013-01-01

Estimating moment to moment changes in blood oxygenation level dependent (BOLD) activation levels from functional magnetic resonance imaging (fMRI) data has applications for learned regulation of regional activation, brain state monitoring, and brain-machine interfaces. In each of these contexts, accurate estimation of the BOLD signal in as little time as possible is desired. This is a challenging problem due to the low signal-to-noise ratio of fMRI data. Previous methods for real-time fMRI analysis have either sacrificed the ability to compute moment to moment activation changes by averaging several acquisitions into a single activation estimate or have sacrificed accuracy by failing to account for prominent sources of noise in the fMRI signal. Here we present a new method for computing the amount of activation present in a single fMRI acquisition that separates moment to moment changes in the fMRI signal intensity attributable to neural sources from those due to noise, resulting in a feedback signal more reflective of neural activation. This method computes an incremental general linear model fit to the fMRI timeseries, which is used to calculate the expected signal intensity at each new acquisition. The difference between the measured intensity and the expected intensity is scaled by the variance of the estimator in order to transform this residual difference into a statistic. Both synthetic and real data were used to validate this method and compare it to the only other published real-time fMRI method. PMID:20682350

BOLD signal and functional connectivity associated with loving kindness meditation

Science.gov (United States)

Garrison, Kathleen A; Scheinost, Dustin; Constable, R Todd; Brewer, Judson A

2014-01-01

Loving kindness is a form of meditation involving directed well-wishing, typically supported by the silent repetition of phrases such as “may all beings be happy,” to foster a feeling of selfless love. Here we used functional magnetic resonance imaging to assess the neural substrate of loving kindness meditation in experienced meditators and novices. We first assessed group differences in blood oxygen level-dependent (BOLD) signal during loving kindness meditation. We next used a relatively novel approach, the intrinsic connectivity distribution of functional connectivity, to identify regions that differ in intrinsic connectivity between groups, and then used a data-driven approach to seed-based connectivity analysis to identify which connections differ between groups. Our findings suggest group differences in brain regions involved in self-related processing and mind wandering, emotional processing, inner speech, and memory. Meditators showed overall reduced BOLD signal and intrinsic connectivity during loving kindness as compared to novices, more specifically in the posterior cingulate cortex/precuneus (PCC/PCu), a finding that is consistent with our prior work and other recent neuroimaging studies of meditation. Furthermore, meditators showed greater functional connectivity during loving kindness between the PCC/PCu and the left inferior frontal gyrus, whereas novices showed greater functional connectivity during loving kindness between the PCC/PCu and other cortical midline regions of the default mode network, the bilateral posterior insula lobe, and the bilateral parahippocampus/hippocampus. These novel findings suggest that loving kindness meditation involves a present-centered, selfless focus for meditators as compared to novices. PMID:24944863

Olfactory responses to natal stream water in sockeye salmon by BOLD fMRI.

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Hiroshi Bandoh

Full Text Available Many studies have shown that juvenile salmon imprint olfactory memory of natal stream odors during downstream migration, and adults recall this stream-specific odor information to discriminate their natal stream during upstream migration for spawning. The odor information processing of the natal stream in the salmon brain, however, has not been clarified. We applied blood oxygenation level-dependent (BOLD functional magnetic resonance imaging to investigate the odor information processing of the natal stream in the olfactory bulb and telencephalon of lacustrine sockeye salmon (Oncorhynchus nerka. The strong responses to the natal stream water were mainly observed in the lateral area of dorsal telencephalon (Dl, which are homologous to the medial pallium (hippocampus in terrestrial vertebrates. Although the concentration of L-serine (1 mM in the control water was 20,000-times higher than that of total amino acid in the natal stream water (47.5 nM, the BOLD signals resulting from the natal stream water were stronger than those by L-serine in the Dl. We concluded that sockeye salmon could process the odor information of the natal stream by integrating information in the Dl area of the telencephalon.

Task-Related Modulations of BOLD Low-Frequency Fluctuations within the Default Mode Network

Science.gov (United States)

Tommasin, Silvia; Mascali, Daniele; Gili, Tommaso; Assan, Ibrahim Eid; Moraschi, Marta; Fratini, Michela; Wise, Richard G.; Macaluso, Emiliano; Mangia, Silvia; Giove, Federico

2017-01-01

Spontaneous low-frequency Blood-Oxygenation Level-Dependent (BOLD) signals acquired during resting state are characterized by spatial patterns of synchronous fluctuations, ultimately leading to the identification of robust brain networks. The resting-state brain networks, including the Default Mode Network (DMN), are demonstrated to persist during sustained task execution, but the exact features of task-related changes of network properties are still not well characterized. In this work we sought to examine in a group of 20 healthy volunteers (age 33 ± 6 years, 8 F/12 M) the relationship between changes of spectral and spatiotemporal features of one prominent resting-state network, namely the DMN, during the continuous execution of a working memory n-back task. We found that task execution impacted on both functional connectivity and amplitude of BOLD fluctuations within large parts of the DMN, but these changes correlated between each other only in a small area of the posterior cingulate. We conclude that combined analysis of multiple parameters related to connectivity, and their changes during the transition from resting state to continuous task execution, can contribute to a better understanding of how brain networks rearrange themselves in response to a task. PMID:28845420

Task-Related Modulations of BOLD Low-Frequency Fluctuations within the Default Mode Network

Directory of Open Access Journals (Sweden)

Silvia Tommasin

2017-07-01

Full Text Available Spontaneous low-frequency Blood-Oxygenation Level-Dependent (BOLD signals acquired during resting state are characterized by spatial patterns of synchronous fluctuations, ultimately leading to the identification of robust brain networks. The resting-state brain networks, including the Default Mode Network (DMN, are demonstrated to persist during sustained task execution, but the exact features of task-related changes of network properties are still not well characterized. In this work we sought to examine in a group of 20 healthy volunteers (age 33 ± 6 years, 8 F/12 M the relationship between changes of spectral and spatiotemporal features of one prominent resting-state network, namely the DMN, during the continuous execution of a working memory n-back task. We found that task execution impacted on both functional connectivity and amplitude of BOLD fluctuations within large parts of the DMN, but these changes correlated between each other only in a small area of the posterior cingulate. We conclude that combined analysis of multiple parameters related to connectivity, and their changes during the transition from resting state to continuous task execution, can contribute to a better understanding of how brain networks rearrange themselves in response to a task.

Increased BOLD activation to predator stressor in subiculum and midbrain of amphetamine-sensitized maternal rats.

Science.gov (United States)

Febo, Marcelo; Pira, Ashley S

2011-03-25

Amphetamine, which is known to cause sensitization, potentiates the hormonal and neurobiological signatures of stress and may also increase sensitivity to stress-inducing stimuli in limbic areas. Trimethylthiazoline (5μL TMT) is a chemical constituent of fox feces that evokes innate fear and activates the neuronal and hormonal signatures of stress in rats. We used blood oxygen level dependent (BOLD) MRI to test whether amphetamine sensitization (1mg/kg, i.p. ×3days) in female rats has a lasting effect on the neural response to a stress-evoking stimulus, the scent of a predator, during the postpartum period. The subiculum and dopamine-enriched midbrain VTA/SN of amphetamine-sensitized but not control mothers showed a greater BOLD signal response to predator odor than a control putrid scent. The greater responsiveness of these two brain regions following stimulant sensitization might impact neural processing in response to stressors in the maternal brain. Copyright © 2010 Elsevier B.V. All rights reserved.

Audiovisual synchrony enhances BOLD responses in a brain network including multisensory STS while also enhancing target-detection performance for both modalities

Science.gov (United States)

Marchant, Jennifer L; Ruff, Christian C; Driver, Jon

2012-01-01

The brain seeks to combine related inputs from different senses (e.g., hearing and vision), via multisensory integration. Temporal information can indicate whether stimuli in different senses are related or not. A recent human fMRI study (Noesselt et al. [2007]: J Neurosci 27:11431–11441) used auditory and visual trains of beeps and flashes with erratic timing, manipulating whether auditory and visual trains were synchronous or unrelated in temporal pattern. A region of superior temporal sulcus (STS) showed higher BOLD signal for the synchronous condition. But this could not be related to performance, and it remained unclear if the erratic, unpredictable nature of the stimulus trains was important. Here we compared synchronous audiovisual trains to asynchronous trains, while using a behavioral task requiring detection of higher-intensity target events in either modality. We further varied whether the stimulus trains had predictable temporal pattern or not. Synchrony (versus lag) between auditory and visual trains enhanced behavioral sensitivity (d') to intensity targets in either modality, regardless of predictable versus unpredictable patterning. The analogous contrast in fMRI revealed BOLD increases in several brain areas, including the left STS region reported by Noesselt et al. [2007: J Neurosci 27:11431–11441]. The synchrony effect on BOLD here correlated with the subject-by-subject impact on performance. Predictability of temporal pattern did not affect target detection performance or STS activity, but did lead to an interaction with audiovisual synchrony for BOLD in inferior parietal cortex. PMID:21953980

MEG and fMRI fusion for nonlinear estimation of neural and BOLD signal changes

Directory of Open Access Journals (Sweden)

Sergey M Plis

2010-11-01

Full Text Available The combined analysis of MEG/EEG and functional MRI measurements can lead to improvement in the description of the dynamical and spatial properties of brain activity. In this paper we empirically demonstrate this improvement using simulated and recorded task related MEG and fMRI activity. Neural activity estimates were derived using a dynamic Bayesian network with continuous real valued parameters by means of a sequential Monte Carlo technique. In synthetic data, we show that MEG and fMRI fusion improves estimation of the indirectly observed neural activity and smooths tracking of the BOLD response. In recordings of task related neural activity the combination of MEG and fMRI produces a result with greater SNR, that confirms the expectation arising from the nature of the experiment. The highly nonlinear model of the BOLD response poses a difficult inference problem for neural activity estimation; computational requirements are also high due to the time and space complexity. We show that joint analysis of the data improves the system's behavior by stabilizing the differential equations system and by requiring fewer computational resources.

Using CO5BOLD models to predict the effects of granulation on colours .

Science.gov (United States)

Bonifacio, P.; Caffau, E.; Ludwig, H.-G.; Steffen, M.; Castelli, F.; Gallagher, A. J.; Prakapavičius, D.; Kučinskas, A.; Cayrel, R.; Freytag, B.; Plez, B.; Homeier, D.

In order to investigate the effects of granulation on fluxes and colours, we computed the emerging fluxes from the models in the CO5BOLD grid with metallicities [M/H]=0.0,-1.0,-2.0 and -3.0. These fluxes have been used to compute colours in different photometric systems. We explain here how our computations have been performed and provide some results.

Dicty_cDB: Contig-U15903-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 2 ( EU435859 ) Dicranosepsis distincta voucher su18 cytochrome o... 34 5.2 2 ( EU435856 ) Dicranosepsis cf....34 5.2 2 ( EF216252 ) Drosophila helvetica voucher YNU00006 cytochrome ... 34 5.2

Moment-to-Moment BOLD Signal Variability Reflects Regional Changes in Neural Flexibility across the Lifespan.

Science.gov (United States)

Nomi, Jason S; Bolt, Taylor S; Ezie, C E Chiemeka; Uddin, Lucina Q; Heller, Aaron S

2017-05-31

Variability of neuronal responses is thought to underlie flexible and optimal brain function. Because previous work investigating BOLD signal variability has been conducted within task-based fMRI contexts on adults and older individuals, very little is currently known regarding regional changes in spontaneous BOLD signal variability in the human brain across the lifespan. The current study used resting-state fMRI data from a large sample of male and female human participants covering a wide age range (6-85 years) across two different fMRI acquisition parameters (TR = 0.645 and 1.4 s). Variability in brain regions including a key node of the salience network (anterior insula) increased linearly across the lifespan across datasets. In contrast, variability in most other large-scale networks decreased linearly over the lifespan. These results demonstrate unique lifespan trajectories of BOLD variability related to specific regions of the brain and add to a growing literature demonstrating the importance of identifying normative trajectories of functional brain maturation. SIGNIFICANCE STATEMENT Although brain signal variability has traditionally been considered a source of unwanted noise, recent work demonstrates that variability in brain signals during task performance is related to brain maturation in old age as well as individual differences in behavioral performance. The current results demonstrate that intrinsic fluctuations in resting-state variability exhibit unique maturation trajectories in specific brain regions and systems, particularly those supporting salience detection. These results have implications for investigations of brain development and aging, as well as interpretations of brain function underlying behavioral changes across the lifespan. Copyright © 2017 the authors 0270-6474/17/375539-10$15.00/0.

Sustained negative BOLD response in human fMRI finger tapping task.

Science.gov (United States)

Liu, Yadong; Shen, Hui; Zhou, Zongtan; Hu, Dewen

2011-01-01

In this work, we investigated the sustained negative blood oxygen level-dependent (BOLD) response (sNBR) using functional magnetic resonance imaging during a finger tapping task. We observed that the sNBR for this task was more extensive than has previously been reported. The cortical regions involved in sNBR are divided into the following three groups: frontal, somatosensory and occipital. By investigating the spatial structure, area, amplitude, and dynamics of the sNBR in comparison with those of its positive BOLD response (PBR) counterpart, we made the following observations. First, among the three groups, the somatosensory group contained the greatest number of activated voxels and the fewest deactivated voxels. In addition, the amplitude of the sNBR in this group was the smallest among the three groups. Second, the onset and peak time of the sNBR are both larger than those of the PBR, whereas the falling edge time of the sNBR is less than that of the PBR. Third, the long distance between most sNBR foci and their corresponding PBR foci makes it unlikely that they share the same blood supply artery. Fourth, the couplings between the sNBR and its PBR counterpart are distinct among different regions and thus should be investigated separately. These findings imply that the origin of most sNBR foci in the finger-tapping task is much more likely to be neuronal activity suppression rather than "blood steal."

Sustained negative BOLD response in human fMRI finger tapping task.

Directory of Open Access Journals (Sweden)

Yadong Liu

Full Text Available In this work, we investigated the sustained negative blood oxygen level-dependent (BOLD response (sNBR using functional magnetic resonance imaging during a finger tapping task. We observed that the sNBR for this task was more extensive than has previously been reported. The cortical regions involved in sNBR are divided into the following three groups: frontal, somatosensory and occipital. By investigating the spatial structure, area, amplitude, and dynamics of the sNBR in comparison with those of its positive BOLD response (PBR counterpart, we made the following observations. First, among the three groups, the somatosensory group contained the greatest number of activated voxels and the fewest deactivated voxels. In addition, the amplitude of the sNBR in this group was the smallest among the three groups. Second, the onset and peak time of the sNBR are both larger than those of the PBR, whereas the falling edge time of the sNBR is less than that of the PBR. Third, the long distance between most sNBR foci and their corresponding PBR foci makes it unlikely that they share the same blood supply artery. Fourth, the couplings between the sNBR and its PBR counterpart are distinct among different regions and thus should be investigated separately. These findings imply that the origin of most sNBR foci in the finger-tapping task is much more likely to be neuronal activity suppression rather than "blood steal."

Exploring BOLD changes during spatial attention in non-stimulated visual cortex.

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Linda Heinemann

Full Text Available Blood oxygen level-dependent (BOLD responses were measured in parts of primary visual cortex that represented unstimulated visual field regions at different distances from a stimulated central target location. The composition of the visual scene varied by the presence or absence of additional peripheral distracter stimuli. Bottom-up effects were assessed by comparing peripheral activity during central stimulation vs. no stimulation. Top-down effects were assessed by comparing active vs. passive conditions. In passive conditions subjects simply watched the central letter stimuli and in active conditions they had to report occurrence of pre-defined targets in a rapid serial letter stream. Onset of the central letter stream enhanced activity in V1 representations of the stimulated region. Within representations of the periphery activation decreased and finally turned into deactivation with increasing distance from the stimulated location. This pattern was most pronounced in the active conditions and during the presence of peripheral stimuli. Active search for a target did not lead to additional enhancement at areas representing the attentional focus but to a stronger deactivation in the vicinity. Suppressed neuronal activity was also found in the non distracter condition suggesting a top-down attention driven effect. Our observations suggest that BOLD signal decreases in primary visual cortex are modulated by bottom-up sensory-driven factors such as the presence of distracters in the visual field as well as by top-down attentional processes.

BOLD VENTURE COMPUTATION SYSTEM for nuclear reactor core analysis, Version III

International Nuclear Information System (INIS)

Vondy, D.R.; Fowler, T.B.; Cunningham, G.W. III.

1981-06-01

This report is a condensed documentation for VERSION III of the BOLD VENTURE COMPUTATION SYSTEM for nuclear reactor core analysis. An experienced analyst should be able to use this system routinely for solving problems by referring to this document. Individual reports must be referenced for details. This report covers basic input instructions and describes recent extensions to the modules as well as to the interface data file specifications. Some application considerations are discussed and an elaborate sample problem is used as an instruction aid. Instructions for creating the system on IBM computers are also given

BOLD VENTURE COMPUTATION SYSTEM for nuclear reactor core analysis, Version III

Energy Technology Data Exchange (ETDEWEB)

Vondy, D.R.; Fowler, T.B.; Cunningham, G.W. III.

1981-06-01

This report is a condensed documentation for VERSION III of the BOLD VENTURE COMPUTATION SYSTEM for nuclear reactor core analysis. An experienced analyst should be able to use this system routinely for solving problems by referring to this document. Individual reports must be referenced for details. This report covers basic input instructions and describes recent extensions to the modules as well as to the interface data file specifications. Some application considerations are discussed and an elaborate sample problem is used as an instruction aid. Instructions for creating the system on IBM computers are also given.

Comparison of fMRI BOLD response patterns by electrical stimulation of the ventroposterior complex and medial thalamus of the rat.

Directory of Open Access Journals (Sweden)

Pai-Feng Yang

Full Text Available The objective of this study was to compare the functional connectivity of the lateral and medial thalamocortical pain pathways by investigating the blood oxygen level-dependent (BOLD activation patterns in the forebrain elicited by direct electrical stimulation of the ventroposterior (VP and medial (MT thalamus. An MRI-compatible stimulation electrode was implanted in the VP or MT of α-chloralose-anesthetized rats. Electrical stimulation was applied to the VP or MT at various intensities (50 µA to 300 µA and frequencies (1 Hz to 12 Hz. BOLD responses were analyzed in the ipsilateral forelimb region of the primary somatosensory cortex (iS1FL after VP stimulation and in the ipsilateral cingulate cortex (iCC after MT stimulation. When stimulating the VP, the strongest activation occurred at 3 Hz. The stimulation intensity threshold was 50 µA and the response rapidly peaked at 100 µA. When stimulating the MT, The optimal frequency for stimulation was 9 Hz or 12 Hz, the stimulation intensity threshold was 100 µA and we observed a graded increase in the BOLD response following the application of higher intensity stimuli. We also evaluated c-Fos expression following the application of a 200-µA stimulus. Ventroposterior thalamic stimulation elicited c-Fos-positivity in few cells in the iS1FL and caudate putamen (iCPu. Medial thalamic stimulation, however, produced numerous c-Fos-positive cells in the iCC and iCPu. The differential BOLD responses and c-Fos expressions elicited by VP and MT stimulation indicate differences in stimulus-response properties of the medial and lateral thalamic pain pathways.

Quantifying [{sup 18}F]fluorodeoxyglucose uptake in the arterial wall: the effects of dual time-point imaging and partial volume effect correction

Energy Technology Data Exchange (ETDEWEB)

Blomberg, Bjoern A. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Odense University Hospital, Department of Nuclear Medicine, Odense (Denmark); Bashyam, Arjun; Ramachandran, Abhinay; Gholami, Saeid; Houshmand, Sina; Salavati, Ali; Werner, Tom; Alavi, Abass [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Zaidi, Habib [Geneva University Hospital, Division of Nuclear Medicine and Molecular Imaging, Geneva (Switzerland); University of Groningen, Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen (Netherlands)

2015-08-15

The human arterial wall is smaller than the spatial resolution of current positron emission tomographs. Therefore, partial volume effects should be considered when quantifying arterial wall {sup 18}F-FDG uptake. We evaluated the impact of a novel method for partial volume effect (PVE) correction with contrast-enhanced CT (CECT) assistance on quantification of arterial wall {sup 18}F-FDG uptake at different imaging time-points. Ten subjects were assessed by CECT imaging and dual time-point PET/CT imaging at approximately 60 and 180 min after {sup 18}F-FDG administration. For both time-points, uptake of {sup 18}F-FDG was determined in the aortic wall by calculating the blood pool-corrected maximum standardized uptake value (cSUV{sub MAX}) and cSUV{sub MEAN}. The PVE-corrected SUV{sub MEAN} (pvcSUV{sub MEAN}) was also calculated using {sup 18}F-FDG PET/CT and CECT images. Finally, corresponding target-to-background ratios (TBR) were calculated. At 60 min, pvcSUV{sub MEAN} was on average 3.1 times greater than cSUV{sub MAX} (P <.0001) and 8.5 times greater than cSUV{sub MEAN} (P <.0001). At 180 min, pvcSUV{sub MEAN} was on average 2.6 times greater than cSUV{sub MAX} (P <.0001) and 6.6 times greater than cSUV{sub MEAN} (P <.0001). This study demonstrated that CECT-assisted PVE correction significantly influences quantification of arterial wall {sup 18}F-FDG uptake. Therefore, partial volume effects should be considered when quantifying arterial wall {sup 18}F-FDG uptake with PET. (orig.)

Application of language blood oxygenation level dependent functional MRI in the navigating operation of neurosurgery

International Nuclear Information System (INIS)

Liu Shuyong; Li Min; Yao Chengjun; Geng Daoying

2011-01-01

Objective: To verify the accuracy of blood oxygenation level dependent (BOLD)-based activation using electrocortical stimulation mapping (ESM) and explore the value of language fMRI in the navigating operation of neurosurgery. Methods: In 8 cases with brain tumors, BOLD-fMRI examinations were done before the operations. Under the state of awake anesthesia,the patients were aroused and ESM was conducted. Point-to-point comparison between the BOLD signal activations and the ESM was carried out under the surveillance of the neuro-navigation technology. In order to observe the sensibility and specificity of BOLD activations, the location of BOLD activations and the point of ESM was compared to calculate the stimulating positive points inside the regions of BOLD signals (real positive), outside BOLD regions (pseudo- negative), the stimulating negative points inside the regions of BOLD signals (pseudo-positive), and outside BOLD region (real negative). Two kinds of criteria for assessment were used. One was that the positive stimulating points were located in BOLD regions, and the other was that the positive stimulating points were located within 1 cm around the range of BOLD regions. Removal of the lesions were conducted with the tissue 1 cm around the language region preserved, and the cortex inside 0.5-1.0 cm distance from the positive points were retained. Results: Of the 8 cases, only 6 finished the tasks. Among them, 3 cases were with astrocytoma of grade 2, 2 were with astrocytoma of grade 3, and one with glioblastoma. The total number of stimulating points was 48, among which the positive points were 11. When the first criteria was applied, the sensitivity was 72.7% (8/11), and the specificity was 81.8% (30/37). When the second criteria was applied, the sensitivity was 82.0% (9/11), and the specificity was 75.6% (28/37). Follow-up after operation showed no aphasia occurred. Conclusions: BOLD-fMRI had a high sensitivity and specificity in displaying the language

Working memory in volunteers and schizophrenics using BOLD fMRI

International Nuclear Information System (INIS)

Giesel, F.L.; Hohmann, N.; Seidl, U.; Kress, K.R.; Schoenknecht, P.; Schroeder, J.; Kauczor, H.-U.; Essig, M.

2005-01-01

Functional magnetic resonance imaging uses the blood oxygen level-dependent effect (BOLD MRI) for noninvasive display of cerebral correlatives of cognitive function. The importance for the understanding of physiological and pathological processes is demonstrated by investigations of working memory in schizophrenics and healthy controls. Working memory is involved in processing rather than storage of information and therefore is linked to complex processes such as learning and problem solving. In schizophrenic psychosis, these functions are clearly restricted. Training effects in the working memory task follow an inverse U-shape function, suggesting that cerebral activation reaches a peak before economics of the brain find a more efficient method and activation decreases. (orig.) [de

Measurement of oxygen extraction fraction (OEF): An optimized BOLD signal model for use with hypercapnic and hyperoxic calibration.

Science.gov (United States)

Merola, Alberto; Murphy, Kevin; Stone, Alan J; Germuska, Michael A; Griffeth, Valerie E M; Blockley, Nicholas P; Buxton, Richard B; Wise, Richard G

2016-04-01

Several techniques have been proposed to estimate relative changes in cerebral metabolic rate of oxygen consumption (CMRO2) by exploiting combined BOLD fMRI and cerebral blood flow data in conjunction with hypercapnic or hyperoxic respiratory challenges. More recently, methods based on respiratory challenges that include both hypercapnia and hyperoxia have been developed to assess absolute CMRO2, an important parameter for understanding brain energetics. In this paper, we empirically optimize a previously presented "original calibration model" relating BOLD and blood flow signals specifically for the estimation of oxygen extraction fraction (OEF) and absolute CMRO2. To do so, we have created a set of synthetic BOLD signals using a detailed BOLD signal model to reproduce experiments incorporating hypercapnic and hyperoxic respiratory challenges at 3T. A wide range of physiological conditions was simulated by varying input parameter values (baseline cerebral blood volume (CBV0), baseline cerebral blood flow (CBF0), baseline oxygen extraction fraction (OEF0) and hematocrit (Hct)). From the optimization of the calibration model for estimation of OEF and practical considerations of hypercapnic and hyperoxic respiratory challenges, a new "simplified calibration model" is established which reduces the complexity of the original calibration model by substituting the standard parameters α and β with a single parameter θ. The optimal value of θ is determined (θ=0.06) across a range of experimental respiratory challenges. The simplified calibration model gives estimates of OEF0 and absolute CMRO2 closer to the true values used to simulate the experimental data compared to those estimated using the original model incorporating literature values of α and β. Finally, an error propagation analysis demonstrates the susceptibility of the original and simplified calibration models to measurement errors and potential violations in the underlying assumptions of isometabolism

Personality and the collective: bold homing pigeons occupy higher leadership ranks in flocks.

Science.gov (United States)

Sasaki, Takao; Mann, Richard P; Warren, Katherine N; Herbert, Tristian; Wilson, Tara; Biro, Dora

2018-05-19

While collective movement is ecologically widespread and conveys numerous benefits on individuals, it also poses a coordination problem: who controls the group's movements? The role that animal 'personalities' play in this question has recently become a focus of research interest. Although many animal groups have distributed leadership (i.e. multiple individuals influence collective decisions), studies linking personality and leadership have focused predominantly on the group's single most influential individual. In this study, we investigate the relationship between personality and the influence of multiple leaders on collective movement using homing pigeons, Columba livia , a species known to display complex multilevel leadership hierarchies during flock flights. Our results show that more exploratory (i.e. 'bold') birds are more likely to occupy higher ranks in the leadership hierarchy and thus have more influence on the direction of collective movement than less exploratory (i.e. 'shy') birds during both free flights around their lofts and homing flights from a distant site. Our data also show that bold pigeons fly faster than shy birds during solo flights. We discuss our results in light of theories about the evolution of personality, with specific reference to the adaptive value of heterogeneity in animal groups.This article is part of the theme issue 'Collective movement ecology'. © 2018 The Author(s).

Task-related modulations of BOLD low-frequency fluctuations within the default mode network

Science.gov (United States)

Tommasin, Silvia; Mascali, Daniele; Gili, Tommaso; Eid Assan, Ibrahim; Moraschi, Marta; Fratini, Michela; Wise, Richard G.; Macaluso, Emiliano; Mangia, Silvia; Giove, Federico

2017-07-01

Spontaneous low-frequency Blood-Oxygenation Level-Dependent (BOLD) signals acquired during resting state are characterized by spatial patterns of synchronous fluctuations, ultimately leading to the identification of robust brain networks. The resting-state brain networks, including the Default Mode Network (DMN), are demonstrated to persist during sustained task execution, but the exact features of task-related changes of network properties are still not well characterized. In this work we sought to examine in a group of 20 healthy volunteers (age 33±6 years, 8F/12M) the relationship between changes of spectral and spatiotemporal features of one prominent resting-state network, namely the DMN, during the steady-state execution of a sustained working memory n-back task. We found that the steady state execution of such a task impacted on both functional connectivity and amplitude of BOLD fluctuations within large parts of the DMN, but these changes correlated between each other only in a small area of the posterior cingulate. We conclude that combined analysis of multiple parameters related to connectivity, and their changes during the transition from resting state to steady-state task execution, can contribute to a better understanding of how brain networks rearrange themselves in response of a task.

Background MR gradient noise and non-auditory BOLD activations: a data-driven perspective.

Science.gov (United States)

Haller, Sven; Homola, György A; Scheffler, Klaus; Beckmann, Christian F; Bartsch, Andreas J

2009-07-28

The effect of echoplanar imaging (EPI) acoustic background noise on blood oxygenation level dependent (BOLD) activations was investigated. Two EPI pulse sequences were compared: (i) conventional EPI with a pulsating sound component of typically 8-10 Hz, which is a potent physiological stimulus, and (ii) the more recently developed continuous-sound EPI, which is perceived as less distractive despite equivalent peak sound pressure levels. Sixteen healthy subjects performed an established demanding visual n-back working memory task. Using an exploratory data analysis technique (tensorial probabilistic independent component analysis; tensor-PICA), we studied the inter-session/within-subject response variability introduced by continuous-sound versus conventional EPI acoustic background noise in addition to temporal and spatial signal characteristics. The analysis revealed a task-related component associated with the established higher-level working memory and motor feedback response network, which exhibited a significant 19% increase in its average effect size for the continuous-sound as opposed to conventional EPI. Stimulus-related lower-level activations, such as primary visual areas, were not modified. EPI acoustic background noise influences much more than the auditory system per se. This analysis provides additional evidence for an enhancement of task-related, extra-auditory BOLD activations by continuous-sound EPI due to less distractive acoustic background gradient noise.

Early Changes in Alpha Band Power and DMN BOLD Activity in Alzheimer’s Disease: A Simultaneous Resting State EEG-fMRI Study

Directory of Open Access Journals (Sweden)

Katharina Brueggen

2017-10-01

Full Text Available Simultaneous resting state functional magnetic resonance imaging (rsfMRI–resting state electroencephalography (rsEEG studies in healthy adults showed robust positive associations of signal power in the alpha band with BOLD signal in the thalamus, and more heterogeneous associations in cortical default mode network (DMN regions. Negative associations were found in occipital regions. In Alzheimer’s disease (AD, rsfMRI studies revealed a disruption of the DMN, while rsEEG studies consistently reported a reduced power within the alpha band. The present study is the first to employ simultaneous rsfMRI-rsEEG in an AD sample, investigating the association of alpha band power and BOLD signal, compared to healthy controls (HC. We hypothesized to find reduced positive associations in DMN regions and reduced negative associations in occipital regions in the AD group. Simultaneous resting state fMRI–EEG was recorded in 14 patients with mild AD and 14 HC, matched for age and gender. Power within the EEG alpha band (8–12 Hz, 8–10 Hz, and 10–12 Hz was computed from occipital electrodes and served as regressor in voxel-wise linear regression analyses, to assess the association with the BOLD signal. Compared to HC, the AD group showed significantly decreased positive associations between BOLD signal and occipital alpha band power in clusters in the superior, middle and inferior frontal cortex, inferior temporal lobe and thalamus (p < 0.01, uncorr., cluster size ≥ 50 voxels. This group effect was more pronounced in the upper alpha sub-band, compared to the lower alpha sub-band. Notably, we observed a high inter-individual heterogeneity. Negative associations were only reduced in the lower alpha range in the hippocampus, putamen and cerebellum. The present study gives first insights into the relationship of resting-state EEG and fMRI characteristics in an AD sample. The results suggest that positive associations between alpha band power and BOLD

Cholinergic enhancement reduces functional connectivity and BOLD variability in visual extrastriate cortex during selective attention.

Science.gov (United States)

Ricciardi, Emiliano; Handjaras, Giacomo; Bernardi, Giulio; Pietrini, Pietro; Furey, Maura L

2013-01-01

Enhancing cholinergic function improves performance on various cognitive tasks and alters neural responses in task specific brain regions. We have hypothesized that the changes in neural activity observed during increased cholinergic function reflect an increase in neural efficiency that leads to improved task performance. The current study tested this hypothesis by assessing neural efficiency based on cholinergically-mediated effects on regional brain connectivity and BOLD signal variability. Nine subjects participated in a double-blind, placebo-controlled crossover fMRI study. Following an infusion of physostigmine (1 mg/h) or placebo, echo-planar imaging (EPI) was conducted as participants performed a selective attention task. During the task, two images comprised of superimposed pictures of faces and houses were presented. Subjects were instructed periodically to shift their attention from one stimulus component to the other and to perform a matching task using hand held response buttons. A control condition included phase-scrambled images of superimposed faces and houses that were presented in the same temporal and spatial manner as the attention task; participants were instructed to perform a matching task. Cholinergic enhancement improved performance during the selective attention task, with no change during the control task. Functional connectivity analyses showed that the strength of connectivity between ventral visual processing areas and task-related occipital, parietal and prefrontal regions reduced significantly during cholinergic enhancement, exclusively during the selective attention task. Physostigmine administration also reduced BOLD signal temporal variability relative to placebo throughout temporal and occipital visual processing areas, again during the selective attention task only. Together with the observed behavioral improvement, the decreases in connectivity strength throughout task-relevant regions and BOLD variability within stimulus

ATLAS - Civil Engineering - Surface Buildings Point 1.8

CERN Multimedia

Jacob-Rols, J.

2000-01-01

Photo1-SMA18 building January 03, 2000 Photo2-Helium tanks foundation January 11, 2000 Photo3-SHM building January 12, 2000 Photo4-SHM18 Landscaping October 04, 2000 Photo5-Landscaping October 12, 2000 Photo6-Landscaping October 25, 2000 Photo7-Landscaping November 08, 2000 Photo8-Landscaping November 08, 2000 Photo9-Landscaping November 15, 2000 Photo10-Landscaping November 22, 2000

The Relationship Between Dopamine Neurotransmitter Dynamics and the Blood-Oxygen-Level-Dependent (BOLD Signal: A Review of Pharmacological Functional Magnetic Resonance Imaging

Directory of Open Access Journals (Sweden)

Tyler J. Bruinsma

2018-04-01

Full Text Available Functional magnetic resonance imaging (fMRI is widely used in investigations of normal cognition and brain disease and in various clinical applications. Pharmacological fMRI (pharma-fMRI is a relatively new application, which is being used to elucidate the effects and mechanisms of pharmacological modulation of brain activity. Characterizing the effects of neuropharmacological agents on regional brain activity using fMRI is challenging because drugs modulate neuronal function in a wide variety of ways, including through receptor agonist, antagonist, and neurotransmitter reuptake blocker events. Here we review current knowledge on neurotransmitter-mediated blood-oxygen-level dependent (BOLD fMRI mechanisms as well as recently updated methodologies aimed at more fully describing the effects of neuropharmacologic agents on the BOLD signal. We limit our discussion to dopaminergic signaling as a useful lens through which to analyze and interpret neurochemical-mediated changes in the hemodynamic BOLD response. We also discuss the need for future studies that use multi-modal approaches to expand the understanding and application of pharma-fMRI.

Accurate experimental determination of the isotope effects on the triple point temperature of water. II. Combined dependence on the 18O and 17O abundances

Science.gov (United States)

Faghihi, V.; Kozicki, M.; Aerts-Bijma, A. T.; Jansen, H. G.; Spriensma, J. J.; Peruzzi, A.; Meijer, H. A. J.

2015-12-01

This paper is the second of two articles on the quantification of isotope effects on the triple point temperature of water. In this second article, we address the combined effects of 18O and 17O isotopes. We manufactured five triple point cells with waters with 18O and 17O abundances exceeding widely the natural abundance range while maintaining their natural 18O/17O relationship. The 2H isotopic abundance was kept close to that of VSMOW (Vienna Standard Mean Ocean Water). These cells realized triple point temperatures ranging between  -220 μK to 1420 μK with respect to the temperature realized by a triple point cell filled with VSMOW. Our experiment allowed us to determine an accurate and reliable value for the newly defined combined 18, 17O correction parameter of AO  =  630 μK with a combined uncertainty of 10 μK. To apply this correction, only the 18O abundance of the TPW needs to be known (and the water needs to be of natural origin). Using the results of our two articles, we recommend a correction equation along with the coefficient values for isotopic compositions differing from that of VSMOW and compare the effect of this new equation on a number of triple point cells from the literature and from our own institute. Using our correction equation, the uncertainty in the isotope correction for triple point cell waters used around the world will be  <1 μK.

Spatial–temporal signature of resting-state BOLD signals in classic trigeminal neuralgia

Directory of Open Access Journals (Sweden)

Wang Y

2017-12-01

Full Text Available Yanping Wang,1 Congying Xu,1 Liping Zhai,1 Xudong Lu,1 Xiaoqiang Wu,1 Yahui Yi,2 Ziyun Liu,1 Qiaobing Guan,1 Xiaoling Zhang1 1Department of Neurology, the Second Hospital of Jiaxing City, Jiaxing, Zhejiang, 2Department of Radiology, the Second Hospital of Jiaxing City, Jiaxing, Zhejiang, China Abstract: Resting-state functional magnetic resonance imaging (R-fMRI signals are spatiotemporally organized. R-fMRI studies in patients with classic trigeminal neuralgia (CTN have suggested alterations in functional connectivity. However, far less attention has been given to investigations of the local oscillations and their frequency-specific changes in these patients. The objective of this study was to address this issue in patients with CTN. R-fMRI data from 17 patients with CTN and 19 age- and gender-matched healthy controls (HCs were analyzed using amplitude of low-frequency fluctuation (ALFF. The ALFF was computed across different frequencies (slow-4: 0.027–0.073 Hz; slow-5: 0.01–0.027 Hz; and typical band: 0.01–0.08 Hz in patients with CTN compared to HCs. In the typical band, patients with CTN showed increases of ALFF in bilateral temporal, occipital, and left middle frontal regions and in the left middle cingulate gyrus, as well as decreases of ALFF in the right inferior temporal region and in regions (medial prefrontal regions of default mode network. These significant group differences were identified in different sub-bands, with greater brainstem findings in higher frequencies (slow-4 and extensive default mode network and right postparietal results in lower frequencies (slow-5. Furthermore, significant relationships were found between subjective pain ratings and both amplitudes of higher frequency (slow-4 blood oxygen level-dependent (BOLD signals in pain localization brain regions and lower frequencies (slow-5 in pain signaling/modulating brain regions in the patients, and decreased ALFF within the prefrontal regions was significantly

The Fine Art of Writing a Will

DEFF Research Database (Denmark)

Blicher, Henrik

2015-01-01

A thorough examination of Jens Baggesen’s use of Don Quijote in his acclaimed 18th century sentimental travelogue proves the young Danish classicist to be an ardent reader as well as a bold bricoleur. Jens Baggesen has chosen the knight of the sad countenance as his travelling companion, the epis......A thorough examination of Jens Baggesen’s use of Don Quijote in his acclaimed 18th century sentimental travelogue proves the young Danish classicist to be an ardent reader as well as a bold bricoleur. Jens Baggesen has chosen the knight of the sad countenance as his travelling companion......, the epistemological nature of Baggesen’s adventures is called into question, and the knight’s last will is restaged at a crucial point in order to account for the author’s very credibility....

Consistency in boldness, activity and exploration at different stages of life

Science.gov (United States)

2013-01-01

Background Animals show consistent individual behavioural patterns over time and over situations. This phenomenon has been referred to as animal personality or behavioural syndromes. Little is known about consistency of animal personalities over entire life times. We investigated the repeatability of behaviour in common voles (Microtus arvalis) at different life stages, with different time intervals, and in different situations. Animals were tested using four behavioural tests in three experimental groups: 1. before and after maturation over three months, 2. twice as adults during one week, and 3. twice as adult animals over three months, which resembles a substantial part of their entire adult life span of several months. Results Different behaviours were correlated within and between tests and a cluster analysis showed three possible behavioural syndrome-axes, which we name boldness, exploration and activity. Activity and exploration behaviour in all tests was highly repeatable in adult animals tested over one week. In animals tested over maturation, exploration behaviour was consistent whereas activity was not. Voles that were tested as adults with a three-month interval showed the opposite pattern with stable activity but unstable exploration behaviour. Conclusions The consistency in behaviour over time suggests that common voles do express stable personality over short time. Over longer periods however, behaviour is more flexible and depending on life stage (i.e. tested before/after maturation or as adults) of the tested individual. Level of boldness or activity does not differ between tested groups and maintenance of variation in behavioural traits can therefore not be explained by expected future assets as reported in other studies. PMID:24314274

Shy and bold great tits (Parus major): body temperature and breath rate in response to handling stress

NARCIS (Netherlands)

Carere, C.; Van Oers, K.

2004-01-01

A standard handling protocol was used to test the hypothesis that boldness predicts stress responsiveness in body temperature and breath rate. Great tit (Parus major) nestlings were taken from the field, hand reared until independence, and their response to a novel object was assessed. At the age of

Shy and bold great tits (Parus major) : body temperature and breath rate in response to handling stress

NARCIS (Netherlands)

Carere, C; van Oers, K

2004-01-01

A standard handling protocol was used to test the hypothesis that boldness predicts stress responsiveness in body temperature and breath rate. Great tit (Parus major) nestlings were taken from the field, hand reared until independence, and their response to a novel object was assessed. At the age of

Dual time point 2-deoxy-2-[18F]fluoro-D-glucose PET/CT: nodal staging in locally advanced breast cancer.

Science.gov (United States)

García Vicente, A M; Soriano Castrejón, A; Cruz Mora, M Á; Ortega Ruiperez, C; Espinosa Aunión, R; León Martín, A; González Ageitos, A; Van Gómez López, O

2014-01-01

To assess dual time point 2-deoxy-2-[(18)F]fluoro-D-glucose (18)(F)FDG PET-CT accuracy in nodal staging and in detection of extra-axillary involvement. Dual time point [(18)F] FDG PET/CT scan was performed in 75 patients. Visual and semiquantitative assessment of lymph nodes was performed. Semiquantitative measurement of SUV and ROC-analysis were carried out to calculate SUV(max) cut-off value with the best diagnostic performance. Axillary and extra-axillary lymph node chains were evaluated. Sensitivity and specificity of visual assessment was 87.3% and 75%, respectively. SUV(max) values with the best sensitivity were 0.90 and 0.95 for early and delayed PET, respectively. SUV(max) values with the best specificity were 1.95 and 2.75, respectively. Extra-axillary lymph node involvement was detected in 26.7%. FDG PET/CT detected extra-axillary lymph node involvement in one-fourth of the patients. Semiquantitative lymph node analysis did not show any advantage over the visual evaluation. Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.

Teacherpreneurs: a bold brand of teacher leadership for 21st-century teaching and learning.

Science.gov (United States)

Berry, Barnett

2013-04-19

Challenges facing our public schools demand a bold brand of teacher leadership. Teacherpreneurs, effective teachers who teach students regularly but also incubate and execute the kinds of policies and pedagogies students deserve, represent a new culture of training and ingenuity. Teachers who lead outside the classroom but do not lose their connection to students are best positioned to develop and disseminate best policies and practices for 21st-century teaching and learning.

Visual cortex and auditory cortex activation in early binocularly blind macaques: A BOLD-fMRI study using auditory stimuli.

Science.gov (United States)

Wang, Rong; Wu, Lingjie; Tang, Zuohua; Sun, Xinghuai; Feng, Xiaoyuan; Tang, Weijun; Qian, Wen; Wang, Jie; Jin, Lixin; Zhong, Yufeng; Xiao, Zebin

2017-04-15

Cross-modal plasticity within the visual and auditory cortices of early binocularly blind macaques is not well studied. In this study, four healthy neonatal macaques were assigned to group A (control group) or group B (binocularly blind group). Sixteen months later, blood oxygenation level-dependent functional imaging (BOLD-fMRI) was conducted to examine the activation in the visual and auditory cortices of each macaque while being tested using pure tones as auditory stimuli. The changes in the BOLD response in the visual and auditory cortices of all macaques were compared with immunofluorescence staining findings. Compared with group A, greater BOLD activity was observed in the bilateral visual cortices of group B, and this effect was particularly obvious in the right visual cortex. In addition, more activated volumes were found in the bilateral auditory cortices of group B than of group A, especially in the right auditory cortex. These findings were consistent with the fact that there were more c-Fos-positive cells in the bilateral visual and auditory cortices of group B compared with group A (p visual cortices of binocularly blind macaques can be reorganized to process auditory stimuli after visual deprivation, and this effect is more obvious in the right than the left visual cortex. These results indicate the establishment of cross-modal plasticity within the visual and auditory cortices. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Boldness towards novelty and translocation success in captive-raised, orphaned Tasmanian devils.

Science.gov (United States)

Sinn, David L; Cawthen, Lisa; Jones, Susan M; Pukk, Chrissy; Jones, Menna E

2014-01-01

Translocation of endangered animals is common, but success is often variable and/or poor. Despite its intuitive appeal, little is known with regards to how individual differences amongst translocated animals influence their post-release survival, growth, and reproduction. We measured consistent pre-release responses to novelty in a familiar environment (boldness; repeatability=0.55) and cortisol response in a group of captive-reared Tasmanian devils, currently listed as "Endangered" by the IUCN. The devils were then released at either a hard- or soft-release site within their mothers' population of origin, and individual growth, movement, reproduction (females only), and survival across 2-8 months post-release was measured. Sex, release method, cohort, behavior, and cortisol response did not affect post-release growth, nor did these factors influence the home range size of orphan devils. Final linear distances moved from the release site were impacted heavily by the release cohort, but translocated devils' movement overall was not different from that in the same-age wild devils. All orphan females of reproductive age were subsequently captured with offspring. Overall survival rates in translocated devils were moderate (∼42%), and were not affected by devil sex, release method, cohort, release weight, or pre-release cortisol response. Devils that survived during the study period were, however, 3.5 times more bold than those that did not (effect size r=0.76). Our results suggest that conservation managers may need to provide developmental conditions in captivity that promote a wide range of behaviors across individuals slated for wild release. © 2013 Wiley Periodicals, Inc.

Textural features and SUV-based variables assessed by dual time point 18F-FDG PET/CT in locally advanced breast cancer.

Science.gov (United States)

Garcia-Vicente, Ana María; Molina, David; Pérez-Beteta, Julián; Amo-Salas, Mariano; Martínez-González, Alicia; Bueno, Gloria; Tello-Galán, María Jesús; Soriano-Castrejón, Ángel

2017-12-01

To study the influence of dual time point 18F-FDG PET/CT in textural features and SUV-based variables and their relation among them. Fifty-six patients with locally advanced breast cancer (LABC) were prospectively included. All of them underwent a standard 18F-FDG PET/CT (PET-1) and a delayed acquisition (PET-2). After segmentation, SUV variables (SUVmax, SUVmean, and SUVpeak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were obtained. Eighteen three-dimensional (3D) textural measures were computed including: run-length matrices (RLM) features, co-occurrence matrices (CM) features, and energies. Differences between all PET-derived variables obtained in PET-1 and PET-2 were studied. Significant differences were found between the SUV-based parameters and MTV obtained in the dual time point PET/CT, with higher values of SUV-based variables and lower MTV in the PET-2 with respect to the PET-1. In relation with the textural parameters obtained in dual time point acquisition, significant differences were found for the short run emphasis, low gray-level run emphasis, short run high gray-level emphasis, run percentage, long run emphasis, gray-level non-uniformity, homogeneity, and dissimilarity. Textural variables showed relations with MTV and TLG. Significant differences of textural features were found in dual time point 18F-FDG PET/CT. Thus, a dynamic behavior of metabolic characteristics should be expected, with higher heterogeneity in delayed PET acquisition compared with the standard PET. A greater heterogeneity was found in bigger tumors.

The Clinical Role of Dual-Time-Point {sup 18}F-FDG PET/CT in Differential Diagnosis of the Thyroid Incidentaloma

Energy Technology Data Exchange (ETDEWEB)

Lee, Sinae; Park, Taegyu; Park, Soyeon; Pahk, Kisoo; Rhee, Seunghong; Cho, Jaehyuk; Jeong, Eugene; Kim, Sungeun; Choe, Jae Gol [Korea Univ., Seoul (Korea, Republic of)

2014-06-15

Thyroid incidentalomas are common findings during imaging studies including {sup 18}F-fluorodeoxyglucose ({sup 18}F-FDG) positron emission tomography/computed tomography (PET/CT) for cancer evaluation. Although the overall incidence of incidental thyroid uptake detected on PET imaging is low, clinical attention should be warranted owing to the high incidence of harboring primary thyroid malignancy.We retrospectively reviewed 2,368 dual-time-point {sup 18}F-FDG PET/CT cases that were undertaken for cancer evaluation from November 2007 to February 2009, to determine the clinical impact of dual-time-point imaging in the differential diagnosis of thyroid incidentalomas. Focal thyroid uptake was identified in 64 PET cases and final diagnosis was clarified with cytology/histology in a total of 27 patients with {sup 18}F-FDG-avid incidental thyroid lesion. The maximum standardized uptake value (SUVmax) of the initial image (SUV1) and SUVmax of the delayed image (SUV2) were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1 (i. e., RI=[SUV2-SUV1]/SUV1Χ100). These indices were compared between patient groups that were proven to have pathologically benign or malignant thyroid lesions. There was no statistically significant difference in SUV1 between benign and malignant lesions. SUV2 and RI of the malignant lesions were significantly higher than the benign lesions. The areas under the ROC curves showed that SUV2 and RI have the ability to discriminate between benign and malignant thyroid lesions. The predictability of dual-time-point PET parameters for thyroid malignancy was assessed by ROC curve analyses. When SUV2 of 3.9 was used as cut-off threshold, malignancy on the pathology could be predicted with a sensitivity of 87.5 % and specificity of 75 %. A thyroid lesion that shows RI greater than 12.5 % could be expected to be malignant (sensitivity 88.9 %, specificity 66.3 %). All malignant lesions showed an

Dual-time-point 18F-FDG PET imaging for diagnosis of disease type and disease activity in patients with idiopathic interstitial pneumonia

International Nuclear Information System (INIS)

Umeda, Yukihiro; Demura, Yoshiki; Ishizaki, Takeshi; Ameshima, Shingo; Miyamori, Isamu; Saito, Yuji; Tsuchida, Tatsuro; Fujibayashi, Yasuhisa; Okazawa, Hidehiko

2009-01-01

Individual clinical courses of idiopathic interstitial pneumonia (IIP) are variable and difficult to predict because the pathology and disease activity are contingent, and chest computed tomography (CT) provides little information about disease activity. In this study, we applied dual-time-point [ 18 F]-fluoro-2-deoxy-D-glucose ( 18 F-FDG) positron emission tomography (PET), commonly used for diagnosis of malignant tumours, to the differential diagnosis and prediction of disease progression in IIP patients. Fifty patients with IIP, including idiopathic pulmonary fibrosis (IPF, n = 21), non-specific interstitial pneumonia (NSIP, n = 18) and cryptogenic organizing pneumonia (COP, n = 11), underwent 18 F-FDG PET examinations at two time points: scan 1 at 60 min (early imaging) and scan 2 at 180 min (delayed imaging) after 18 F-FDG injection. The standardized uptake values (SUV) at the two points and the retention index (RI-SUV) calculated from them were evaluated and compared with chest CT findings, disease progression and disease types. To evaluate short-term disease progression, all patients were examined by pulmonary function test every 3 months for 1 year after 18 F-FDG PET scanning. The early SUV for COP (2.47 ± 0.74) was significantly higher than that for IPF (0.99 ± 0.29, p = 0.0002) or NSIP (1.22 ± 0.44, p= 0.0025). When an early SUV cut-off value of 1.5 and greater was used to distinguish COP from IPF and NSIP, the sensitivity, specificity and accuracy were 90.9, 94.3 and 93.5%, respectively. The RI-SUV for IPF and NSIP lesions was significantly greater in patients with deteriorated pulmonary function after 1 year of follow-up (progressive group, 13.0 ± 8.9%) than in cases without deterioration during the 1-year observation period (stable group, -16.8 ± 5.9%, p 18 F-FDG PET are useful parameters for the differential diagnosis and prediction of disease progression in patients with IIP. (orig.)

Spatial-temporal-spectral EEG patterns of BOLD functional network connectivity dynamics

Science.gov (United States)

Lamoš, Martin; Mareček, Radek; Slavíček, Tomáš; Mikl, Michal; Rektor, Ivan; Jan, Jiří

2018-06-01

Objective. 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 electroencephalogram (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. The simultaneously acquired BOLD fMRI data were decomposed by independent component analysis. Dynamic functional connectivity was computed on the component’s time series using a sliding window correlation, and between-network connectivity states were then defined based on the values of the correlation coefficients. ANOVA tests were performed to assess the relationships between the dynamics of between-network connectivity states and the fluctuations of EEG spectral patterns. Main results. We found three patterns related to the dynamics of between-network connectivity states. The first pattern has dominant peaks in the alpha, beta, and gamma bands and is related to the dynamics between the auditory, sensorimotor, and attentional networks. The second pattern, with dominant peaks in the theta and low alpha bands, is related to the visual and default mode network. The third pattern, also with peaks in the theta and low alpha bands, is related to the auditory and frontal network. Significance. Our previous findings revealed a relationship between EEG spectral pattern fluctuations and the hemodynamics of large-scale brain networks. In this study, we suggest that the relationship also exists at the level of functional connectivity dynamics among large-scale brain networks when no standard spatial and spectral

Sickly slaves, soldiers and sailors. Contextualising the Cape's 18th–19th century Green Point burials through isotope investigation

NARCIS (Netherlands)

Mbeki, Linda; Kootker, Lisette M.; Kars, Henk; Davies, Gareth R.

2017-01-01

Strontium isotope data of multiple dental enamel samples, and carbon and nitrogen isotope data of dentine and bone collagen samples from 27 individuals excavated from the mid-18th to mid-19th century Victoria & Albert Marina Residence paupers burial ground in the vicinity of Green Point, Cape Town,

SU-D-207A-03: Potential Role of BOLD MRI in Discrimination of Aggressive Tumor Habitat in Prostate Cancer

Energy Technology Data Exchange (ETDEWEB)

Ford, J; Lopez, C; Tschudi, Y; Breto, A; Padgett, K; Pollack, A; Stoyanova, R [University of Miami Miller School of Medicine, Miami, FL (United States)

2016-06-15

Purpose: To determine whether blood oxygenation level dependent (BOLD) MRI signal measured in prostate cancer patients, in addition to quantitative diffusion and perfusion parameters from multiparametric (mp)MRI exams, can help discriminate aggressive and/or radioresistant lesions. Methods: Several ongoing clinical trials in our institution require mpMRI exam to determine eligibility (presence of identifiable tumor lesion on mpMRI) and prostate volumes for dose escalation. Upon consent, patients undergo fiducial markers placement and a T2*-weighted imaging at the time of CT sim to facilitate the fusion. In a retrospective analysis eleven clinical trial patients were identified who had undergone mpMRI on GE 3T magnet, followed by T2*-weighted imaging (time-period mean±SD = 48±20 days) using a consistent protocol (gradient echo, TR/TE=30/11.8ms, flip angle=12, matrix=256×256×75, voxel size=1.25×1.25×2.5mm). ROIs for prostate tumor lesions were automatically determined using ADC threshold ≤1200 µm2/s. Although the MR protocol was not intended for BOLD analysis, we utilized the T2*-weighted signal normalized to that in nearby muscle; likewise, T2-weighted lesion signal was normalized to muscle, following rigid registration of the T2 to T2* images. The ratio of these normalized signals, T2*/T2, is a measure of BOLD effect in the prostate tumors. Perfusion parameters (Ktrans, ve, kep) were also calculated. Results: T2*/T2 (mean±SE) was found to be substantially lower for Gleason score (GS) 8&9 (0.82±0.04) compared to GS 7 (1.08±0.07). A k-means cluster analysis of T2*/T2 versus kep = Ktrans/ve revealed two distinct clusters, one with higher T2*/T2 and lower kep, containing only GS 7 lesions, and another with lower T2*/T2 and higher kep, associated with tumor aggressiveness. This latter cluster contained all GS 8&9 lesions, as well as some GS 7. Conclusion: BOLD MRI, in addition to ADC and kep, may play a role (perhaps orthogonal to Gleason score) in

The effect of Rickia wasmannii (Ascomycota, Laboulbeniales on the aggression and boldness of Myrmica scabrinodis (Hymenoptera, Formicidae

Directory of Open Access Journals (Sweden)

Ferenc Báthori

2017-08-01

Full Text Available The interactions of ectosymbiotic Laboulbeniales (Ascomycota fungi and their hosts are rather understudied. Rickia wasmannii Cavara is a common ant-associated Laboulbeniales species that has been reported in 17 countries of Europe, and frequently infects Myrmica scabrinodis Nylander, 1846 (Hymenoptera: Formicidae, a common ant species host, in high density. These make M. scabrinodis and R. wasmannii appropriate model organisms for studies on fungal host-ectosymbiont interactions. Aggressiveness and boldness of infected and uninfected M. scabrinodis workers from northern and eastern Hungary were studied in two laboratory-established behavioural experiments. Infected workers were significantly less aggressive and less bold (i.e. less likely to leave nest shelters than the uninfected ones. These results suggest that R. wasmannii has considerable effects on the behaviour of M. scabrinodis. Our study brings an evidence that infection of ants with Laboulbeniales might negatively affect the workers’ behaviour. In special, the competitive abilities might be affected most by these fungi, since remaining inside and behaving submissively is not effective behaviour in the case of significant competition for resources among colonies.

Boldness in a deep sea hermit crab to simulated tactile predator attacks is unaffected by ocean acidification

Science.gov (United States)

Kim, Tae Won; Barry, James P.

2016-09-01

Despite rapidly growing interest in the effects of ocean acidification on marine animals, the ability of deep-sea animals to acclimate or adapt to reduced pH conditions has received little attention. Deep-sea species are generally thought to be less tolerant of environmental variation than shallow-living species because they inhabit relatively stable conditions for nearly all environmental parameters. To explore whether deep-sea hermit crabs ( Pagurus tanneri) can acclimate to ocean acidification over several weeks, we compared behavioral "boldness," measured as time taken to re-emerge from shells after a simulated predatory attack by a toy octopus, under ambient (pH ˜7.6) and expected future (pH ˜7.1) conditions. The boldness measure for crab behavioral responses did not differ between different pH treatments, suggesting that future deep-sea acidification would not influence anti-predatory behavior. However, we did not examine the effects of olfactory cues released by predators that may affect hermit crab behavior and could be influenced by changes in the ocean carbonate system driven by increasing CO2 levels.

Experience of Dual Time Point Brain F-18 FDG PET/CT Imaging in Patients with Infections Disease

Energy Technology Data Exchange (ETDEWEB)

Kim, Dae Weung; Kim, Chang Guhn; Park, Soon Ah; Jung, Sang Ah [Wonkwang University School of Medicine, Iksan (Korea, Republic of)

2010-06-15

Dual time point FDG PET imaging (DTPI) has been considered helpful for discrimination of benign and malignant disease, and staging lymph node status in patients with pulmonary malignancy. However, DTPI for benign disease has been rarely reported, and it may show a better description of metabolic status and extent of benign infection disease than early imaging only. The authors report on the use F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) imaging with additional delayed imaging on a 52-year-old man with sparganosis and a 70-year-old man with tuberculous meningitis. To the best of our knowledge, this is the first report on dual time point PET/CT imaging in patients with cerebral sparganosis and tuberculous meningitis.

Low prevalence of obstructive lung disease in a suburban population of Malaysia: A BOLD collaborative study.

Science.gov (United States)

Loh, Li Cher; Rashid, Abdul; Sholehah, Siti; Gnatiuc, Louisa; Patel, Jaymini H; Burney, Peter

2016-08-01

As a Burden of Obstructive Lung Disease (BOLD) collaboration, we studied the prevalence of chronic obstructive pulmonary disease (COPD) and its associated risk factors in a suburban population in Malaysia. Nonhospitalized men or women of age ≥ 40 years from a Penang district were recruited by stratified simple random sampling. Participants completed detailed questionnaires on respiratory symptoms and exposure to COPD risk factors. Prebronchodilator and post-bronchodilator spirometry conducted was standardized across all international BOLD sites in device and data quality control. Of the 1218 individuals recruited for the study, 663 (340 men and 323 women) had complete questionnaire data and acceptable post-bronchodilator spirometry. The estimated population prevalence of Global Initiative for Chronic Obstructive Lung Disease (GOLD) ≥ stage I was 6.5% or 3.4% based on either fixed forced expiratory volume in 1 s/forced vital capacity ratio of population-based epidemiology data on COPD for Malaysia. Compared with other sites globally, our estimated population prevalence was relatively low. In addition to cigarette smoking, use of biomass fuel and exposure to dusty job represented significant risk to the development of COPD. © 2016 Asian Pacific Society of Respirology.

fMRI BOLD response to the eyes task in offspring from multiplex alcohol dependence families.

Science.gov (United States)

Hill, Shirley Y; Kostelnik, Bryan; Holmes, Brian; Goradia, Dhruman; McDermott, Michael; Diwadkar, Vaibhav; Keshavan, Matcheri

2007-12-01

Increased susceptibility for developing alcohol dependence (AD) may be related to structural and functional differences in brain circuits that influence social cognition and more specifically, theory of mind (ToM). Alcohol dependent individuals have a greater likelihood of having deficits in social skills and greater social alienation. These characteristics may be related to inherited differences in the neuroanatomical network that comprises the social brain. Adolescent/young adult participants from multiplex AD families and controls (n = 16) were matched for gender, age, IQ, education, and handedness and administered the Eyes Task of Baron-Cohen during functional magnetic resonance imaging (fMRI). High-risk (HR) subjects showed significantly diminished blood oxygen level dependent (BOLD) response in comparison with low-risk control young adults in the right middle temporal gyrus (RMTG) and the left inferior frontal gyrus (LIFG), areas that have previously been implicated in ToM tasks. Offspring from multiplex families for AD may manifest one aspect of their genetic susceptibility by having a diminished BOLD response in brain regions associated with performance of ToM tasks. These results suggest that those at risk for developing AD may have reduced ability to empathize with others' state of mind, possibly resulting in diminished social skill.

Detecting Activation in fMRI Data: An Approach Based on Sparse Representation of BOLD Signal

Directory of Open Access Journals (Sweden)

Blanca Guillen

2018-01-01

Full Text Available This paper proposes a simple yet effective approach for detecting activated voxels in fMRI data by exploiting the inherent sparsity property of the BOLD signal in temporal and spatial domains. In the time domain, the approach combines the General Linear Model (GLM with a Least Absolute Deviation (LAD based regression method regularized by the pseudonorm l0 to promote sparsity in the parameter vector of the model. In the spatial domain, detection of activated regions is based on thresholding the spatial map of estimated parameters associated with a particular stimulus. The threshold is calculated by exploiting the sparseness of the BOLD signal in the spatial domain assuming a Laplacian distribution model. The proposed approach is validated using synthetic and real fMRI data. For synthetic data, results show that the proposed approach is able to detect most activated voxels without any false activation. For real data, the method is evaluated through comparison with the SPM software. Results indicate that this approach can effectively find activated regions that are similar to those found by SPM, but using a much simpler approach. This study may lead to the development of robust spatial approaches to further simplifying the complexity of classical schemes.

Mapping and characterization of positive and negative BOLD responses to visual stimulation in multiple brain regions at 7T.

Science.gov (United States)

Jorge, João; Figueiredo, Patrícia; Gruetter, Rolf; van der Zwaag, Wietske

2018-02-20

External stimuli and tasks often elicit negative BOLD responses in various brain regions, and growing experimental evidence supports that these phenomena are functionally meaningful. In this work, the high sensitivity available at 7T was explored to map and characterize both positive (PBRs) and negative BOLD responses (NBRs) to visual checkerboard stimulation, occurring in various brain regions within and beyond the visual cortex. Recently-proposed accelerated fMRI techniques were employed for data acquisition, and procedures for exclusion of large draining vein contributions, together with ICA-assisted denoising, were included in the analysis to improve response estimation. Besides the visual cortex, significant PBRs were found in the lateral geniculate nucleus and superior colliculus, as well as the pre-central sulcus; in these regions, response durations increased monotonically with stimulus duration, in tight covariation with the visual PBR duration. Significant NBRs were found in the visual cortex, auditory cortex, default-mode network (DMN) and superior parietal lobule; NBR durations also tended to increase with stimulus duration, but were significantly less sustained than the visual PBR, especially for the DMN and superior parietal lobule. Responses in visual and auditory cortex were further studied for checkerboard contrast dependence, and their amplitudes were found to increase monotonically with contrast, linearly correlated with the visual PBR amplitude. Overall, these findings suggest the presence of dynamic neuronal interactions across multiple brain regions, sensitive to stimulus intensity and duration, and demonstrate the richness of information obtainable when jointly mapping positive and negative BOLD responses at a whole-brain scale, with ultra-high field fMRI. © 2018 Wiley Periodicals, Inc.

Mapping and characterization of positive and negative BOLD responses to visual stimulation in multiple brain regions at 7T

NARCIS (Netherlands)

Jorge, João; Figueiredo, Patrícia; Gruetter, Rolf; Van der Zwaag, W.

External stimuli and tasks often elicit negative BOLD responses in various brain regions, and growing experimental evidence supports that these phenomena are functionally meaningful. In this work, the high sensitivity available at 7T was explored to map and characterize both positive (PBRs) and

Frequency-dependent tACS modulation of BOLD signal during rhythmic visual stimulation.

Science.gov (United States)

Chai, Yuhui; Sheng, Jingwei; Bandettini, Peter A; Gao, Jia-Hong

2018-05-01

Transcranial alternating current stimulation (tACS) has emerged as a promising tool for modulating cortical oscillations. In previous electroencephalogram (EEG) studies, tACS has been found to modulate brain oscillatory activity in a frequency-specific manner. However, the spatial distribution and hemodynamic response for this modulation remains poorly understood. Functional magnetic resonance imaging (fMRI) has the advantage of measuring neuronal activity in regions not only below the tACS electrodes but also across the whole brain with high spatial resolution. Here, we measured fMRI signal while applying tACS to modulate rhythmic visual activity. During fMRI acquisition, tACS at different frequencies (4, 8, 16, and 32 Hz) was applied along with visual flicker stimulation at 8 and 16 Hz. We analyzed the blood-oxygen-level-dependent (BOLD) signal difference between tACS-ON vs tACS-OFF, and different frequency combinations (e.g., 4 Hz tACS, 8 Hz flicker vs 8 Hz tACS, 8 Hz flicker). We observed significant tACS modulation effects on BOLD responses when the tACS frequency matched the visual flicker frequency or the second harmonic frequency. The main effects were predominantly seen in regions that were activated by the visual task and targeted by the tACS current distribution. These findings bridge different scientific domains of tACS research and demonstrate that fMRI could localize the tACS effect on stimulus-induced brain rhythms, which could lead to a new approach for understanding the high-level cognitive process shaped by the ongoing oscillatory signal. © 2018 Wiley Periodicals, Inc.

Integration of BOLD-fMRI and DTI into radiation treatment planning for high-grade gliomas located near the primary motor cortexes and corticospinal tracts

International Nuclear Information System (INIS)

Wang, Minglei; Ma, Hui; Wang, Xiaodong; Guo, Yanhong; Xia, Xinshe; Xia, Hechun; Guo, Yulin; Huang, Xueying; He, Hong; Jia, Xiaoxiong; Xie, Yan

2015-01-01

The main objective of this study was to evaluate the efficacy of integrating the blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI) and diffusion tensor imaging (DTI) data into radiation treatment planning for high-grade gliomas located near the primary motor cortexes (PMCs) and corticospinal tracts (CSTs). A total of 20 patients with high-grade gliomas adjacent to PMCs and CSTs between 2012 and 2014 were recruited. The bilateral PMCs and CSTs were located in the normal regions without any overlapping with target volume of the lesions. BOLD-fMRI, DTI and conventional MRI were performed on patients (Karnofsky performance score ≥ 70) before radical radiotherapy treatment. Four different imaging studies were conducted in each patient: a planning computed tomography (CT), an anatomical MRI, a DTI and a BOLD-fMRI. For each case, three treatment plans (3DCRT, IMRT and IMRT-PMC&CST) were developed by 3 different physicists using the Pinnacle planning system. Our study has shown that there was no significant difference between the 3DCRT and IMRT plans in terms of dose homogeneity, but IMRT displayed better planning target volume (PTV) dose conformity. In addition, we have found that the Dmax and Dmean to the ipsilateral and contralateral PMC and CST regions were considerably decreased in IMRT-PMC&CST group (p < 0.001). In conclusion, integration of BOLD-fMRI and DTI into radiation treatment planning is feasible and beneficial. With the assistance of the above-described techniques, the bilateral PMCs and CSTs adjacent to the target volume could be clearly marked as OARs and spared during treatment

Physiological denoising of BOLD fMRI data using Regressor Interpolation at Progressive Time Delays (RIPTiDe) processing of concurrent fMRI and near-infrared spectroscopy (NIRS).

Science.gov (United States)

Frederick, Blaise deB; Nickerson, Lisa D; Tong, Yunjie

2012-04-15

Confounding noise in BOLD fMRI data arises primarily from fluctuations in blood flow and oxygenation due to cardiac and respiratory effects, spontaneous low frequency oscillations (LFO) in arterial pressure, and non-task related neural activity. Cardiac noise is particularly problematic, as the low sampling frequency of BOLD fMRI ensures that these effects are aliased in recorded data. Various methods have been proposed to estimate the noise signal through measurement and transformation of the cardiac and respiratory waveforms (e.g. RETROICOR and respiration volume per time (RVT)) and model-free estimation of noise variance through examination of spatial and temporal patterns. We have previously demonstrated that by applying a voxel-specific time delay to concurrently acquired near infrared spectroscopy (NIRS) data, we can generate regressors that reflect systemic blood flow and oxygenation fluctuations effects. Here, we apply this method to the task of removing physiological noise from BOLD data. We compare the efficacy of noise removal using various sets of noise regressors generated from NIRS data, and also compare the noise removal to RETROICOR+RVT. We compare the results of resting state analyses using the original and noise filtered data, and we evaluate the bias for the different noise filtration methods by computing null distributions from the resting data and comparing them with the expected theoretical distributions. Using the best set of processing choices, six NIRS-generated regressors with voxel-specific time delays explain a median of 10.5% of the variance throughout the brain, with the highest reductions being seen in gray matter. By comparison, the nine RETROICOR+RVT regressors together explain a median of 6.8% of the variance in the BOLD data. Detection of resting state networks was enhanced with NIRS denoising, and there were no appreciable differences in the bias of the different techniques. Physiological noise regressors generated using

Dual-time-point {sup 18}F-FDG PET imaging for diagnosis of disease type and disease activity in patients with idiopathic interstitial pneumonia

Energy Technology Data Exchange (ETDEWEB)

Umeda, Yukihiro; Demura, Yoshiki; Ishizaki, Takeshi; Ameshima, Shingo [University of Fukui, Department of Respiratory Medicine, Yoshida-gun, Fukui (Japan); Miyamori, Isamu [University of Fukui, Third Department of Internal Medicine, Yoshida-gun, Fukui (Japan); Saito, Yuji [Fujita Health University, Division of Respirology and Allergology, Department of Internal Medicine, School of Medicine, Toyoake, Aichi (Japan); Tsuchida, Tatsuro [University of Fukui, Department of Radiology, Yoshida-gun, Fukui (Japan); Fujibayashi, Yasuhisa; Okazawa, Hidehiko [University of Fukui, Biomedical Imaging Research Center, Yoshida-gun, Fukui (Japan)

2009-07-15

Individual clinical courses of idiopathic interstitial pneumonia (IIP) are variable and difficult to predict because the pathology and disease activity are contingent, and chest computed tomography (CT) provides little information about disease activity. In this study, we applied dual-time-point [{sup 18}F]-fluoro-2-deoxy-D-glucose ({sup 18}F-FDG) positron emission tomography (PET), commonly used for diagnosis of malignant tumours, to the differential diagnosis and prediction of disease progression in IIP patients. Fifty patients with IIP, including idiopathic pulmonary fibrosis (IPF, n = 21), non-specific interstitial pneumonia (NSIP, n = 18) and cryptogenic organizing pneumonia (COP, n = 11), underwent {sup 18}F-FDG PET examinations at two time points: scan 1 at 60 min (early imaging) and scan 2 at 180 min (delayed imaging) after {sup 18}F-FDG injection. The standardized uptake values (SUV) at the two points and the retention index (RI-SUV) calculated from them were evaluated and compared with chest CT findings, disease progression and disease types. To evaluate short-term disease progression, all patients were examined by pulmonary function test every 3 months for 1 year after {sup 18}F-FDG PET scanning. The early SUV for COP (2.47 {+-} 0.74) was significantly higher than that for IPF (0.99 {+-} 0.29, p = 0.0002) or NSIP (1.22 {+-} 0.44, p= 0.0025). When an early SUV cut-off value of 1.5 and greater was used to distinguish COP from IPF and NSIP, the sensitivity, specificity and accuracy were 90.9, 94.3 and 93.5%, respectively. The RI-SUV for IPF and NSIP lesions was significantly greater in patients with deteriorated pulmonary function after 1 year of follow-up (progressive group, 13.0 {+-} 8.9%) than in cases without deterioration during the 1-year observation period (stable group, -16.8 {+-} 5.9%, p < 0.0001). However, the early SUV for all IIP types provided no additional information of disease progression. When an RI-SUV cut-off value of 0% and greater was

Gamma-ray-induced bold seeded early maturing groundnut selections

International Nuclear Information System (INIS)

Manoharan, V.; Thangavelu, S.

1990-01-01

Full text: ''Chico'' is an early maturing (85-90 days) erect groundnut (Arachis hypogaea L.) genotype utilised in groundnut improvement to incorporate earliness in high yielding varieties. Though it has high shelling out-turn, its yield potential is low since it has small seeds. Mutation breeding was started with the objective of improving the seed size. In a preliminary experiment, dry seeds were treated with 20, 30, 40 or 50 kR of gamma rays. The M 1 generation was grown during the post rainy season of 1988-1989. The M 2 generation was planted as individual plant progeny rows during the rainy season of 1989. 105 progeny rows were studied, the total number of M 2 plants being 1,730. All the M 2 plants were harvested 90 days after sowing. Seven mutants with bold seed size were obtained. The mutants had 100 kernel weight ranging from 22.2 to 40.4 g compared to 21.1 g of control. The study is in progress. (author)

Bold Ideas for the 4th H in 4-H: Teen Identified Concerns and Actions

OpenAIRE

Virginia Brown; Bonnie Braun; JoAnne Leatherman

2015-01-01

This article summarizes a literature review; teen-identified health concerns and issues; and teen bold ideas for actions. Findings from the National 4-H Council and Molina Healthcare Teens Take on Health initiative are provided and implications for 4-H programming tied to the new Cooperative Extension National Framework for Health and Wellness are addressed. The article is intended as background for Extension educators, volunteers and administrators as they review the 4-H Healthy Living Missi...

Airflow Obstruction and Use of Solid Fuels for Cooking or Heating: BOLD Results.

Science.gov (United States)

Amaral, André F S; Patel, Jaymini; Kato, Bernet S; Obaseki, Daniel O; Lawin, Hervé; Tan, Wan C; Juvekar, Sanjay K; Harrabi, Imed; Studnicka, Michael; Wouters, Emiel F M; Loh, Li-Cher; Bateman, Eric D; Mortimer, Kevin; Buist, A Sonia; Burney, Peter G J

2017-09-12

Evidence supporting the association of COPD or airflow obstruction with use of solid fuels is conflicting and inconsistent. To assess the association of airflow obstruction with self-reported use of solid fuels for cooking or heating. We analysed 18,554 adults from the BOLD study, who had provided acceptable post-bronchodilator spirometry measurements and information on use of solid fuels. The association of airflow obstruction with use of solid fuels for cooking or heating was assessed by sex, within each site, using regression analysis. Estimates were stratified by national income and meta-analysed. We carried out similar analyses for spirometric restriction, chronic cough and chronic phlegm. We found no association between airflow obstruction and use of solid fuels for cooking or heating (ORmen=1.20, 95%CI 0.94-1.53; ORwomen=0.88, 95%CI 0.67-1.15). This was true for low/middle and high income sites. Among never smokers there was also no evidence of an association of airflow obstruction with use of solid fuels (ORmen=1.00, 95%CI 0.57-1.76; ORwomen=1.00, 95%CI 0.76-1.32). Overall, we found no association of spirometric restriction, chronic cough or chronic phlegm with the use of solid fuels. However, we found that chronic phlegm was more likely to be reported among female never smokers and those who had been exposed for ≥20 years. Airflow obstruction assessed from post-bronchodilator spirometry was not associated with use of solid fuels for cooking or heating.

Rearing environment influences boldness and prey acquisition behavior, and brain and lens development of bull trout

Science.gov (United States)

Brignon, William R.; Pike, Martin M.; Ebbesson, Lars O.E.; Schaller, Howard A.; Peterson, James T.; Schreck, Carl B.

2018-01-01

Animals reared in barren captive environments exhibit different developmental trajectories and behaviors than wild counterparts. Hence, the captive phenotypes may influence the success of reintroduction and recovery programs for threatened and endangered species. We collected wild bull trout embryos from the Metolius River Basin, Oregon and reared them in differing environments to better understand how captivity affects the bull trout Salvelinus confluentusphenotype. We compared the boldness and prey acquisition behaviors and development of the brain and eye lens of bull trout reared in conventional barren and more structurally complex captive environments with that of wild fish. Wild fish and captive reared fish from complex habitats exhibited a greater level of boldness and prey acquisition ability, than fish reared in conventional captive environments. In addition, the eye lens of conventionally reared bull trout was larger than complex reared captive fish or same age wild fish. Interestingly, we detected wild fish had a smaller relative cerebellum than either captive reared treatment. Our results suggest that rearing fish in more complex captive environments can create a more wild-like phenotype than conventional rearing practices. A better understanding of the effects of captivity on the development and behavior of bull trout can inform rearing and reintroduction programs though prediction of the performance of released individuals.

Functional dissociation of transient and sustained fMRI BOLD components in human auditory cortex revealed with a streaming paradigm based on interaural time differences.

Science.gov (United States)

Schadwinkel, Stefan; Gutschalk, Alexander

2010-12-01

A number of physiological studies suggest that feature-selective adaptation is relevant to the pre-processing for auditory streaming, the perceptual separation of overlapping sound sources. Most of these studies are focused on spectral differences between streams, which are considered most important for streaming. However, spatial cues also support streaming, alone or in combination with spectral cues, but physiological studies of spatial cues for streaming remain scarce. Here, we investigate whether the tuning of selective adaptation for interaural time differences (ITD) coincides with the range where streaming perception is observed. FMRI activation that has been shown to adapt depending on the repetition rate was studied with a streaming paradigm where two tones were differently lateralized by ITD. Listeners were presented with five different ΔITD conditions (62.5, 125, 187.5, 343.75, or 687.5 μs) out of an active baseline with no ΔITD during fMRI. The results showed reduced adaptation for conditions with ΔITD ≥ 125 μs, reflected by enhanced sustained BOLD activity. The percentage of streaming perception for these stimuli increased from approximately 20% for ΔITD = 62.5 μs to > 60% for ΔITD = 125 μs. No further sustained BOLD enhancement was observed when the ΔITD was increased beyond ΔITD = 125 μs, whereas the streaming probability continued to increase up to 90% for ΔITD = 687.5 μs. Conversely, the transient BOLD response, at the transition from baseline to ΔITD blocks, increased most prominently as ΔITD was increased from 187.5 to 343.75 μs. These results demonstrate a clear dissociation of transient and sustained components of the BOLD activity in auditory cortex. © 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

The Rule of Three for Prizes in Science and the Bold Triptychs of Francis Bacon.

Science.gov (United States)

Goldstein, Joseph L

2016-09-22

For many scientific awards, such as Nobels and Laskers, the maximum number of recipients is three. This Rule of Three forces selection committees to make difficult decisions that increase the likelihood of singling out those individuals who open a new field and continue to lead it. The Rule of Three is reminiscent of art's three-panel triptych, a form that the modern master Francis Bacon used to distill complex stories in a bold way. Copyright © 2016 Elsevier Inc. All rights reserved.

Regional nodal staging with 18F-FDG PET–CT in non-small cell lung cancer: Additional diagnostic value of CT attenuation and dual-time-point imaging

International Nuclear Information System (INIS)

Li, Meng; Wu, Ning; Liu, Ying; Zheng, Rong; Liang, Ying; Zhang, Wenjie; Zhao, Ping

2012-01-01

Background: [Fluorine-18]-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET–CT) is widely performed in the regional nodal staging of non-small cell lung cancer (NSCLC). However, the uptake of 18 F-FDG by tubercular granulomatous tissues may lead to false-positive diagnosis. This is of special concern in China, where tubercular granulomatous disease is epidemic. Herein, we evaluated the efficacy of an additional CT attenuation and a dual-time-point scan in determining the status of lymph nodes. Methods: Eighty NSCLC patients underwent curative surgical resection after 18 F-FDG PET–CT and separate breath-hold CT examinations. The initial images were analyzed by two methods. In method 1, nodal status was determined by 18 F-FDG uptake only. In Method 2, nodal status was determined by 18 F-FDG uptake associated with CT attenuation. For dual-time-point imaging, the retention index (RI) of benign and malignant nodal groups with positive uptake in the initial scan was examined. Results: A total of 265 nodal groups were documented. On a per-nodal-group basis, the diagnostic sensitivity, specificity, and accuracy of Method 1 were 66.7%, 89.7%, and 85.3%, respectively, whereas those of Method 2 were 64.7%, 96.7%, and 90.6%, respectively. The improvement in diagnostic specificity and accuracy associated with the addition of CT attenuation in Method 2 as compared to Method 1 was statistically significant (p 0.05). Conclusion: 18 F-FDG PET–CT has high diagnostic value for preoperative lymph-node (N) staging of NSCLC patients. We show that 18 F-FDG uptake combined with CT attenuation improves the diagnostic specificity and accuracy of nodal diagnosis in NSCLC. For the lymph nodes with positive uptake in the initial scan, dual-time-point imaging has limited effect in differentiation.

[{sup 18}F]DPA-714, [{sup 18}F]PBR111 and [{sup 18}F]FEDAA1106-Selective radioligands for imaging TSPO 18 kDa with PET: Automated radiosynthesis on a TRACERLAb FX-FN synthesizer and quality controls

Energy Technology Data Exchange (ETDEWEB)

Kuhnast, Bertrand, E-mail: bertrand.kuhnast@cea.fr [CEA, I2BM, Service Hospitalier Frederic Joliot, 4 Place du General Leclerc, F-91401, Orsay Cedex (France); Damont, Annelaure; Hinnen, Francoise; Catarina, Tony; Demphel, Stephane; Le Helleix, Stephane; Coulon, Christine; Goutal, Sebastien; Gervais, Philippe; Dolle, Frederic [CEA, I2BM, Service Hospitalier Frederic Joliot, 4 Place du General Leclerc, F-91401, Orsay Cedex (France)

2012-03-15

Imaging of TSPO 18 kDa with PET is more and more considered as a relevant biomarker of inflammation in numerous diseases. Development of new radiotracers for TSPO 18 kDa has seen acceleration in the last years and the challenge today is to make available large amounts of such a radiotracer in compliance with GMP standards for application in humans. We present in this technical note automated productions of [{sup 18}F]DPA-714, [{sup 18}F]PBR111 and [{sup 18}F]FEDAA1106, three promising radiotracers for TSPO 18 kDa imaging, using a TRACERlab FX-FN synthesizer. This note also includes the quality control data of the validation batches for the manufacturing qualification of clinical production of [{sup 18}F]DPA-714. - Highlights: Black-Right-Pointing-Pointer Protein TSPO 18 kDa is recognized as a biomarker of inflammation involved in many diseases. Black-Right-Pointing-Pointer Radiotracers targeting TSPO prepared in compliance with GMPs are mandatory as new imaging tools. Black-Right-Pointing-Pointer An automated radiosynthesis of promising radiotracers and full QC have been implemented.

Gamma-ray-induced bold seeded early maturing groundnut selections

Energy Technology Data Exchange (ETDEWEB)

Manoharan, V; Thangavelu, S [Regional Research Station, Vriddhachalam, Tamil Nadu (India)

1990-07-01

Full text: ''Chico'' is an early maturing (85-90 days) erect groundnut (Arachis hypogaea L.) genotype utilised in groundnut improvement to incorporate earliness in high yielding varieties. Though it has high shelling out-turn, its yield potential is low since it has small seeds. Mutation breeding was started with the objective of improving the seed size. In a preliminary experiment, dry seeds were treated with 20, 30, 40 or 50 kR of gamma rays. The M{sub 1} generation was grown during the post rainy season of 1988-1989. The M{sub 2} generation was planted as individual plant progeny rows during the rainy season of 1989. 105 progeny rows were studied, the total number of M{sub 2} plants being 1,730. All the M{sub 2} plants were harvested 90 days after sowing. Seven mutants with bold seed size were obtained. The mutants had 100 kernel weight ranging from 22.2 to 40.4 g compared to 21.1 g of control. The study is in progress. (author)

Role of 3T multiparametric-MRI with BOLD hypoxia imaging for diagnosis and post therapy response evaluation of postoperative recurrent cervical cancers

International Nuclear Information System (INIS)

Mahajan, Abhishek; Engineer, Reena; Chopra, Supriya; Mahanshetty, Umesh; Juvekar, S.L.; Shrivastava, S.K.; Desekar, Naresh; Thakur, M.H.

2015-01-01

•In operated cervix cancer, the accuracy of diagnosing vaginal vault/local recurrent lesions was higher at combined multiparametric MR imaging and conventional MR imaging (100%) than at conventional MR imaging (70%) or multiparametric MR imaging (96.7%) alone.•We found a significant correlation between percentage tumor regression and pre-treatment parameters: NEI (p = 0.02), the maximum slope (p = 0.04), mADC value (p = 0.001) and amount of hypoxic fraction present in the pretherapy MRI (p = 0.01).•Multiparametric and BOLD hypoxia MR Imaging are feasible and reliable in diagnosing post-operative recurrence in cervical cancer and should be applied when there is clinical suspicion of post-operative recurrence.•Quantitative image features obtained at multiparametric-MRI with BOLD hypoxia imaging has potential to be an appropriate and reliable biologic target for radiation dose painting to optimize therapy in future. In operated cervix cancer, the accuracy of diagnosing vaginal vault/local recurrent lesions was higher at combined multiparametric MR imaging and conventional MR imaging (100%) than at conventional MR imaging (70%) or multiparametric MR imaging (96.7%) alone. We found a significant correlation between percentage tumor regression and pre-treatment parameters: NEI (p = 0.02), the maximum slope (p = 0.04), mADC value (p = 0.001) and amount of hypoxic fraction present in the pretherapy MRI (p = 0.01). Multiparametric and BOLD hypoxia MR Imaging are feasible and reliable in diagnosing post-operative recurrence in cervical cancer and should be applied when there is clinical suspicion of post-operative recurrence. Quantitative image features obtained at multiparametric-MRI with BOLD hypoxia imaging has potential to be an appropriate and reliable biologic target for radiation dose painting to optimize therapy in future. To assess the diagnostic value of multiparametric-MRI (MPMRI) with hypoxia imaging as a functional marker for characterizing and detecting

Consistent inter-individual differences in common marmosets (Callithrix jacchus) in Boldness-Shyness, Stress-Activity, and Exploration-Avoidance.

Science.gov (United States)

Šlipogor, Vedrana; Gunhold-de Oliveira, Tina; Tadić, Zoran; Massen, Jorg J M; Bugnyar, Thomas

2016-09-01

The study of animal personality, defined as consistent inter-individual differences in correlated behavioral traits stable throughout time and/or contexts, has recently become one of the fastest growing areas in animal biology, with study species ranging from insects to non-human primates. The latter have, however, only occasionally been tested with standardized experiments. Instead their personality has usually been assessed using questionnaires. Therefore, this study aimed to test 21 common marmosets (Callithrix jacchus) living in three family groups, in five different experiments, and their corresponding controls. We found that behavioral differences between our animals were not only consistent over time, but also across different contexts. Moreover, the consistent behaviors formed a construct of four major non-social personality components: Boldness-Shyness in Foraging, Boldness-Shyness in Predation, Stress-Activity, and Exploration-Avoidance. We found no sex or age differences in these components, but our results did reveal differences in Exploration-Avoidance between the three family groups. As social environment can have a large influence on behavior of individuals, our results may suggest group-level similarity in personality (i.e., "group personality") in common marmosets, a species living in highly cohesive social groups. Am. J. Primatol. 78:961-973, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

21 CFR 200.5 - Mailing of important information about drugs.

Science.gov (United States)

2010-04-01

.... “Important” shall be in 36 point Gothic Bold type. “Drug” and “Warning” shall be in 36 point Gothic Condensed... shall be in three lines, all capitals, and centered. “Important” shall be in 36 point Gothic Bold type. “Prescribing” and “Information” shall be in 36 point Gothic Condensed type. The rectangle's border and the...

Food intake rates of inactive fish are positively linked to boldness in three‐spined sticklebacks Gasterosteus aculeatus

Science.gov (United States)

Manica, A.; Boogert, N. J.

2016-01-01

To investigate the link between personality and maximum food intake of inactive individuals, food‐deprived three‐spined sticklebacks Gasterosteus aculeatus at rest in their home compartments were provided with ad libitum prey items. Bolder individuals ate considerably more than shyer individuals, even after accounting for body size, while sociability did not have an effect. These findings support pace‐of‐life theory predicting that life‐history strategies are linked to boldness. PMID:26940195

Pre-stimulus BOLD-network activation modulates EEG spectral activity during working memory retention

Directory of Open Access Journals (Sweden)

Mara eKottlow

2015-05-01

Full Text Available Working memory (WM processes depend on our momentary mental state and therefore exhibit considerable fluctuations. Here, we investigate the interplay of task-preparatory and task-related brain activity as represented by pre-stimulus BOLD-fluctuations and spectral EEG from the retention periods of a visual WM task. Visual WM is used to maintain sensory information in the brain enabling the performance of cognitive operations and is associated with mental health.We tested 22 subjects simultaneously with EEG and fMRI while performing a visuo-verbal Sternberg task with two different loads, allowing for the temporal separation of preparation, encoding, retention and retrieval periods.Four temporally coherent networks - the default mode network (DMN, the dorsal attention, the right and the left WM network - were extracted from the continuous BOLD data by means of a group ICA. Subsequently, the modulatory effect of these networks’ pre-stimulus activation upon retention-related EEG activity in the theta, alpha and beta frequencies was analyzed. The obtained results are informative in the context of state-dependent information processing.We were able to replicate two well-known load-dependent effects: the frontal-midline theta increase during the task and the decrease of pre-stimulus DMN activity. As our main finding, these two measures seem to depend on each other as the significant negative correlations at frontal-midline channels suggested. Thus, suppressed pre-stimulus DMN levels facilitated later task related frontal midline theta increases. In general, based on previous findings that neuronal coupling in different frequency bands may underlie distinct functions in WM retention, our results suggest that processes reflected by spectral oscillations during retention seem not only to be online synchronized with activity in different attention-related networks but are also modulated by activity in these networks during preparation intervals.

Impact of dual-time-point F-18 FDG PET/CT in the assessment of pleural effusion in patients with non-small-cell lung cancer.

Science.gov (United States)

Alkhawaldeh, Khaled; Biersack, Hans-J; Henke, Anna; Ezziddin, Samer

2011-06-01

The aim of this study was to assess the utility of dual-time-point F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) in differentiating benign from malignant pleural disease, in patients with non-small-cell lung cancer. A total of 61 patients with non-small-cell lung cancer and pleural effusion were included in this retrospective study. All patients had whole-body FDG PET/CT imaging at 60 ± 10 minutes post-FDG injection, whereas 31 patients had second-time delayed imaging repeated at 90 ± 10 minutes for the chest. Maximum standardized uptake values (SUV(max)) and the average percent change in SUV(max) (%SUV) between time point 1 and time point 2 were calculated. Malignancy was defined using the following criteria: (1) visual assessment using 3-points grading scale; (2) SUV(max) ≥2.4; (3) %SUV ≥ +9; and (4) SUV(max) ≥2.4 and/or %SUV ≥ +9. Analysis of variance test and receiver operating characteristic analysis were used in statistical analysis. P < 0.05 was considered significant. Follow-up revealed 29 patient with malignant pleural disease and 31 patients with benign pleural effusion. The average SUV(max) in malignant effusions was 6.5 ± 4 versus 2.2 ± 0.9 in benign effusions (P < 0.0001). The average %SUV in malignant effusions was +13 ± 10 versus -8 ± 11 in benign effusions (P < 0.0004). Sensitivity, specificity, and accuracy for the 5 criteria were as follows: (1) 86%, 72%, and 79%; (2) 93%, 72%, and 82%; (3) 67%, 94%, and 81%; (4) 100%, 94%, and 97%. Dual-time-point F-18 FDG PET can improve the diagnostic accuracy in differentiating benign from malignant pleural disease, with high sensitivity and good specificity.

Negative BOLD in sensory cortices during verbal memory: a component in generating internal representations?

Science.gov (United States)

Azulay, Haim; Striem, Ella; Amedi, Amir

2009-05-01

People tend to close their eyes when trying to retrieve an event or a visual image from memory. However the brain mechanisms behind this phenomenon remain poorly understood. Recently, we showed that during visual mental imagery, auditory areas show a much more robust deactivation than during visual perception. Here we ask whether this is a special case of a more general phenomenon involving retrieval of intrinsic, internally stored information, which would result in crossmodal deactivations in other sensory cortices which are irrelevant to the task at hand. To test this hypothesis, a group of 9 sighted individuals were scanned while performing a memory retrieval task for highly abstract words (i.e., with low imaginability scores). We also scanned a group of 10 congenitally blind, which by definition do not have any visual imagery per se. In sighted subjects, both auditory and visual areas were robustly deactivated during memory retrieval, whereas in the blind the auditory cortex was deactivated while visual areas, shown previously to be relevant for this task, presented a positive BOLD signal. These results suggest that deactivation may be most prominent in task-irrelevant sensory cortices whenever there is a need for retrieval or manipulation of internally stored representations. Thus, there is a task-dependent balance of activation and deactivation that might allow maximization of resources and filtering out of non relevant information to enable allocation of attention to the required task. Furthermore, these results suggest that the balance between positive and negative BOLD might be crucial to our understanding of a large variety of intrinsic and extrinsic tasks including high-level cognitive functions, sensory processing and multisensory integration.

Complex motor task associated with non-linear BOLD responses in cerebro-cortical areas and cerebellum.

Science.gov (United States)

Alahmadi, Adnan A S; Samson, Rebecca S; Gasston, David; Pardini, Matteo; Friston, Karl J; D'Angelo, Egidio; Toosy, Ahmed T; Wheeler-Kingshott, Claudia A M

2016-06-01

Previous studies have used fMRI to address the relationship between grip force (GF) applied to an object and BOLD response. However, whilst the majority of these studies showed a linear relationship between GF and neural activity in the contralateral M1 and ipsilateral cerebellum, animal studies have suggested the presence of non-linear components in the GF-neural activity relationship. Here, we present a methodology for assessing non-linearities in the BOLD response to different GF levels, within primary motor as well as sensory and cognitive areas and the cerebellum. To be sensitive to complex forms, we designed a feasible grip task with five GF targets using an event-related visually guided paradigm and studied a cohort of 13 healthy volunteers. Polynomial functions of increasing order were fitted to the data. (1) activated motor areas irrespective of GF; (2) positive higher-order responses in and outside M1, involving premotor, sensory and visual areas and cerebellum; (3) negative correlations with GF, predominantly involving the visual domain. Overall, our results suggest that there are physiologically consistent behaviour patterns in cerebral and cerebellar cortices; for example, we observed the presence of a second-order effect in sensorimotor areas, consistent with an optimum metabolic response at intermediate GF levels, while higher-order behaviour was found in associative and cognitive areas. At higher GF levels, sensory-related cortical areas showed reduced activation, interpretable as a redistribution of the neural activity for more demanding tasks. These results have the potential of opening new avenues for investigating pathological mechanisms of neurological diseases.

Interneuronal systems of the cervical spinal cord assessed with BOLD imaging at 1.5 T

International Nuclear Information System (INIS)

Stracke, C.P.; Schoth, F.; Moeller-Hartmann, W.; Krings, T.; Pettersson, L.G.

2005-01-01

The purpose of this study was to investigate if functional activity with spinal cord somatosensory stimulation can be visualized using BOLD fMRI. We investigated nine healthy volunteers using a somatosensory stimulus generator. The stimuli were applied in three different runs at the first, third, and fifth finger tip of the right hand, respectively, corresponding to dermatomes c6, c7, and c8. The stimuli gave an increase of BOLD signal (activation) in three different locations of the spinal cord and brain stem. First, activations could be seen in the spinal segment corresponding to the stimulated dermatome in seven out of nine volunteers for c6 stimulation, two out of eight for c7, and three out of eight for c8. These activations were located close to the posterior margin of the spinal cord, presumably reflecting synaptic transmission to dorsal horn interneurons. Second, activation in the medulla oblongata was evident in four subjects, most likely corresponding to the location of the nucleus cuneatus. The third location of activation, which was the strongest and most reliable observed was inside the spinal cord in the c3 and c4 segments. Activation at these spinal levels was almost invariably observed independently of the dermatome stimulated (9/9 for c6, 8/8 for c7, and 7/8 for c8 stimulation). These activations may pertain to an interneuronal system at this spinal level. The results are discussed in relation to neurophysiological studies on cervical spinal interneuronal pathways in animals and humans. (orig.)

Bold Ideas for the 4th H in 4-H: Teen Identified Concerns and Actions

Directory of Open Access Journals (Sweden)

Virginia Brown

2015-03-01

Full Text Available This article summarizes a literature review; teen-identified health concerns and issues; and teen bold ideas for actions. Findings from the National 4-H Council and Molina Healthcare Teens Take on Health initiative are provided and implications for 4-H programming tied to the new Cooperative Extension National Framework for Health and Wellness are addressed. The article is intended as background for Extension educators, volunteers and administrators as they review the 4-H Healthy Living Mission Mandate, learn what mattered to teens and consider how to incorporate the findings into state and local 4-H youth development programming.

Single-trial EEG-informed fMRI reveals spatial dependency of BOLD signal on early and late IC-ERP amplitudes during face recognition.

Science.gov (United States)

Wirsich, Jonathan; Bénar, Christian; Ranjeva, Jean-Philippe; Descoins, Médéric; Soulier, Elisabeth; Le Troter, Arnaud; Confort-Gouny, Sylviane; Liégeois-Chauvel, Catherine; Guye, Maxime

2014-10-15

Simultaneous EEG-fMRI has opened up new avenues for improving the spatio-temporal resolution of functional brain studies. However, this method usually suffers from poor EEG quality, especially for evoked potentials (ERPs), due to specific artifacts. As such, the use of EEG-informed fMRI analysis in the context of cognitive studies has particularly focused on optimizing narrow ERP time windows of interest, which ignores the rich diverse temporal information of the EEG signal. Here, we propose to use simultaneous EEG-fMRI to investigate the neural cascade occurring during face recognition in 14 healthy volunteers by using the successive ERP peaks recorded during the cognitive part of this process. N170, N400 and P600 peaks, commonly associated with face recognition, were successfully and reproducibly identified for each trial and each subject by using a group independent component analysis (ICA). For the first time we use this group ICA to extract several independent components (IC) corresponding to the sequence of activation and used single-trial peaks as modulation parameters in a general linear model (GLM) of fMRI data. We obtained an occipital-temporal-frontal stream of BOLD signal modulation, in accordance with the three successive IC-ERPs providing an unprecedented spatio-temporal characterization of the whole cognitive process as defined by BOLD signal modulation. By using this approach, the pattern of EEG-informed BOLD modulation provided improved characterization of the network involved than the fMRI-only analysis or the source reconstruction of the three ERPs; the latter techniques showing only two regions in common localized in the occipital lobe. Copyright © 2014 Elsevier Inc. All rights reserved.

When the Brain Takes 'BOLD' Steps: Real-Time fMRI Neurofeedback Can Further Enhance the Ability to Gradually Self-regulate Regional Brain Activation.

Science.gov (United States)

Sorger, Bettina; Kamp, Tabea; Weiskopf, Nikolaus; Peters, Judith Caroline; Goebel, Rainer

2018-05-15

Brain-computer interfaces (BCIs) based on real-time functional magnetic resonance imaging (rtfMRI) are currently explored in the context of developing alternative (motor-independent) communication and control means for the severely disabled. In such BCI systems, the user encodes a particular intention (e.g., an answer to a question or an intended action) by evoking specific mental activity resulting in a distinct brain state that can be decoded from fMRI activation. One goal in this context is to increase the degrees of freedom in encoding different intentions, i.e., to allow the BCI user to choose from as many options as possible. Recently, the ability to voluntarily modulate spatial and/or temporal blood oxygenation level-dependent (BOLD)-signal features has been explored implementing different mental tasks and/or different encoding time intervals, respectively. Our two-session fMRI feasibility study systematically investigated for the first time the possibility of using magnitudinal BOLD-signal features for intention encoding. Particularly, in our novel paradigm, participants (n=10) were asked to alternately self-regulate their regional brain-activation level to 30%, 60% or 90% of their maximal capacity by applying a selected activation strategy (i.e., performing a mental task, e.g., inner speech) and modulation strategies (e.g., using different speech rates) suggested by the experimenters. In a second step, we tested the hypothesis that the additional availability of feedback information on the current BOLD-signal level within a region of interest improves the gradual-self regulation performance. Therefore, participants were provided with neurofeedback in one of the two fMRI sessions. Our results show that the majority of the participants were able to gradually self-regulate regional brain activation to at least two different target levels even in the absence of neurofeedback. When provided with continuous feedback on their current BOLD-signal level, most

Food intake rates of inactive fish are positively linked to boldness in three-spined sticklebacks Gasterosteus aculeatus.

Science.gov (United States)

Jolles, J W; Manica, A; Boogert, N J

2016-04-01

To investigate the link between personality and maximum food intake of inactive individuals, food-deprived three-spined sticklebacks Gasterosteus aculeatus at rest in their home compartments were provided with ad libitum prey items. Bolder individuals ate considerably more than shyer individuals, even after accounting for body size, while sociability did not have an effect. These findings support pace-of-life theory predicting that life-history strategies are linked to boldness. © 2016 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of The Fisheries Society of the British Isles.

A critical analysis of the tender points in fibromyalgia.

Science.gov (United States)

Harden, R Norman; Revivo, Gadi; Song, Sharon; Nampiaparampil, Devi; Golden, Gary; Kirincic, Marie; Houle, Timothy T

2007-03-01

To pilot methodologies designed to critically assess the American College of Rheumatology's (ACR) diagnostic criteria for fibromyalgia. Prospective, psychophysical testing. An urban teaching hospital. Twenty-five patients with fibromyalgia and 31 healthy controls (convenience sample). Pressure pain threshold was determined at the 18 ACR tender points and five sham points using an algometer (dolorimeter). The patients "algometric total scores" (sums of the patients' average pain thresholds at the 18 tender points) were derived, as well as pain thresholds across sham points. The "algometric total score" could differentiate patients with fibromyalgia from normals with an accuracy of 85.7% (P pain across sham points than across ACR tender points, sham points also could be used for diagnosis (85.7%; Ps tested vs other painful conditions. The points specified by the ACR were only modestly superior to sham points in making the diagnosis. Most importantly, this pilot suggests single points, smaller groups of points, or sham points may be as effective in diagnosing fibromyalgia as the use of all 18 points, and suggests methodologies to definitively test that hypothesis.

[{sup 18}F]FE-SUPPY and [{sup 18}F]FE-SUPPY:2 - metabolic considerations

Energy Technology Data Exchange (ETDEWEB)

Haeusler, Daniela [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Pharmaceutical Technology and Biopharmaceutics, Univ. of Vienna, A-1090 Vienna (Austria); Nics, Lukas [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Nutritional Sciences, Univ. of Vienna, A-1090 Vienna (Austria); Mien, Leonhard-Key [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Pharmaceutical Technology and Biopharmaceutics, Univ. of Vienna, A-1090 Vienna (Austria); Ungersboeck, Johanna [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Inorganic Chemistry, Univ. of Vienna, A-1090 Vienna (Austria); Lanzenberger, Rupert R. [Dept. of Psychiatry and Psychotherapy, Medical Univ. of Vienna, A-1090 Vienna (Austria); Shanab, Karem [Dept. of Drug and Natural Product Synthesis, Univ. of Vienna, A-1090 Vienna (Austria); Sindelar, Karoline M. [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Viernstein, Helmut [Dept. of Pharmaceutical Technology and Biopharmaceutics, Univ. of Vienna, A-1090 Vienna (Austria); Wagner, Karl-Heinz [Dept. of Nutritional Sciences, Univ. of Vienna, A-1090 Vienna (Austria); Dudczak, Robert; Kletter, Kurt [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Wadsak, Wolfgang [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Inorganic Chemistry, Univ. of Vienna, A-1090 Vienna (Austria); Mitterhauser, Markus [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Pharmaceutical Technology and Biopharmaceutics, Univ. of Vienna, A-1090 Vienna (Austria); Hospital Pharmacy of the General Hospital of Vienna, A-1090 Vienna (Austria)], E-mail: markus.mitterhauser@meduniwien.ac.at

2010-05-15

Introduction: Recently, [{sup 18}F]FE-SUPPY and [{sup 18}F]FE-SUPPY:2 were introduced as the first positron emission tomography (PET) tracers for the adenosine A{sub 3} receptor. Thus, aim of the present study was the metabolic characterization of the two adenosine A{sub 3} receptor PET tracers. Methods: In vitro carboxylesterase (CES) experiments were conducted using incubation mixtures containing different concentrations of the two substrates, porcine CES and phosphate-buffered saline. Enzymatic reactions were stopped by adding acetonitrile/methanol (10:1) after various time points and analyzed by a high-performance liquid chromatography (HPLC) standard protocol. In vivo experiments were conducted in male wild-type rats; tracers were injected through a tail vein. Rats were sacrificed after various time points (n=3), and blood and brain samples were collected. Sample cleanup was performed by an HPLC standard protocol. Results: The rate of enzymatic hydrolysis by CES demonstrated Michaelis-Menten constants in a micromolar range (FE-SUPPY, 20.15 {mu}M, and FE-SUPPY:2, 13.11 {mu}M) and limiting velocities of 0.035 and 0.015 {mu}M/min for FE-SUPPY and FE-SUPPY:2, respectively. Degree of metabolism in blood showed the following: 15 min pi 47.7% of [{sup 18}F]FE-SUPPY was intact compared to 33.1% of [{sup 18}F]FE-SUPPY:2; 30 min pi 30.3% intact [{sup 18}F]FE-SUPPY was found compared to 15.6% [{sup 18}F]FE-SUPPY:2. In brain, [{sup 18}F]FE-SUPPY:2 formed an early hydrophilic metabolite, whereas metabolism of [{sup 18}F]FE-SUPPY was not observed before 30 min pi Conclusion: Knowing that metabolism in rats is several times faster than in human, we conclude that [{sup 18}F]FE-SUPPY should be stable for the typical time span of a clinical investigation. As a consequence, from a metabolic point of view, one would tend to decide in favor of [{sup 18}F]FE-SUPPY.

Distributed BOLD-response in association cortex vector state space predicts reaction time during selective attention.

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Musso, Francesco; Konrad, Andreas; Vucurevic, Goran; Schäffner, Cornelius; Friedrich, Britta; Frech, Peter; Stoeter, Peter; Winterer, Georg

2006-02-15

Human cortical information processing is thought to be dominated by distributed activity in vector state space (Churchland, P.S., Sejnowski, T.J., 1992. The Computational Brain. MIT Press, Cambridge.). In principle, it should be possible to quantify distributed brain activation with independent component analysis (ICA) through vector-based decomposition, i.e., through a separation of a mixture of sources. Using event-related functional magnetic resonance imaging (fMRI) during a selective attention-requiring task (visual oddball), we explored how the number of independent components within activated cortical areas is related to reaction time. Prior to ICA, the activated cortical areas were determined on the basis of a General linear model (GLM) voxel-by-voxel analysis of the target stimuli (checkerboard reversal). Two activated cortical areas (temporoparietal cortex, medial prefrontal cortex) were further investigated as these cortical regions are known to be the sites of simultaneously active electromagnetic generators which give rise to the compound event-related potential P300 during oddball task conditions. We found that the number of independent components more strongly predicted reaction time than the overall level of "activation" (GLM BOLD-response) in the left temporoparietal area whereas in the medial prefrontal cortex both ICA and GLM predicted reaction time equally well. Comparable correlations were not seen when principle components were used instead of independent components. These results indicate that the number of independently activated components, i.e., a high level of cortical activation complexity in cortical vector state space, may index particularly efficient information processing during selective attention-requiring tasks. To our best knowledge, this is the first report describing a potential relationship between neuronal generators of cognitive processes, the associated electrophysiological evidence for the existence of distributed networks

Effect of CGRP and sumatriptan on the BOLD response in visual cortex

DEFF Research Database (Denmark)

Asghar, Mohammed Sohail; Hansen, Adam E; Larsson, Henrik B W

2012-01-01

To test the hypothesis that calcitonin gene-related peptide (CGRP) modulates brain activity, we investigated the effect of intravenous CGRP on brain activity in response to a visual stimulus. In addition, we examined if possible alteration in brain activity was reversed by the anti-migraine drug......% of the participants reported headache after CGRP. We found no changes in brain activity after CGRP (P = 0.12) or after placebo (P = 0.41). Sumatriptan did not affect brain activity after CGRP (P = 0.71) or after placebo (P = 0.98). Systemic CGRP or sumatriptan has no direct effects on the BOLD activity in visual...... sumatriptan. Eighteen healthy volunteers were randomly allocated to receive CGRP infusion (1.5 µg/min for 20 min) or placebo. In vivo activity in the visual cortex was recorded before, during and after infusion and after 6 mg subcutaneous sumatriptan by functional magnetic resonance imaging (3 T). 77...

The impact of susceptibility gradients on cartesian and spiral EPI for BOLD fMRI

DEFF Research Database (Denmark)

Sangill, Ryan; Wallentin, Mikkel; Østergaard, Leif

2006-01-01

, with special emphasis on spiral EPI (spiral) and cartesian EPI (EPI) and their performance under influence of induced field gradients (SFGs) and stochastic noise. A numerical method for calculating synthetic MR images is developed and used to simulate BOLD fMRI experiments using EPI and spirals. The data...... is then examined for activation using a pixel-wise t test. Nine subjects are scanned with both techniques while performing a motor task. SPM99 is used for analysing the experimental data. The simulated spirals provide generally higher t scores at low SFGs but lose more strength than EPI at higher SFGs, where EPI...... activation is offset from the true position. In the primary motor area spirals provide significantly higher t scores (P SFG areas spirals provide stronger activation than...

Role of 3T multiparametric-MRI with BOLD hypoxia imaging for diagnosis and post therapy response evaluation of postoperative recurrent cervical cancers

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Abhishek Mahajan

2016-01-01

Conclusion: Conventional-MR with MPMRI significantly increases the diagnostic accuracy for suspected vaginal vault/local recurrence. Post therapy serial MPMRI with hypoxia imaging follow-up objectively documents the response. MPMRI and BOLD hypoxia imaging provide information regarding tumor biology at the molecular, subcellular, cellular and tissue levels and this information may be used as an appropriate and reliable biologic target for radiation dose painting to optimize therapy in future.

Altered auditory BOLD response to conspecific birdsong in zebra finches with stuttered syllables.

Directory of Open Access Journals (Sweden)

Henning U Voss

2010-12-01

Full Text Available How well a songbird learns a song appears to depend on the formation of a robust auditory template of its tutor's song. Using functional magnetic resonance neuroimaging we examine auditory responses in two groups of zebra finches that differ in the type of song they sing after being tutored by birds producing stuttering-like syllable repetitions in their songs. We find that birds that learn to produce the stuttered syntax show attenuated blood oxygenation level-dependent (BOLD responses to tutor's song, and more pronounced responses to conspecific song primarily in the auditory area field L of the avian forebrain, when compared to birds that produce normal song. These findings are consistent with the presence of a sensory song template critical for song learning in auditory areas of the zebra finch forebrain. In addition, they suggest a relationship between an altered response related to familiarity and/or saliency of song stimuli and the production of variant songs with stuttered syllables.

The software design of multi-branch, multi-point remote monitoring system for temperature measurement based on MSP430 and DS18B20

International Nuclear Information System (INIS)

Yu Jun; Yan Yu

2009-01-01

This paper present that the system can acquire the remote temperature measurement data of 40 monitoring points, through the RS-232 serial port and the Intranet. System's hardware is consist of TI's MSP430F149 mixed-signal processor and UA7000A network module. Using digital temperature sensor DS18B20, the structure is simple and easy to expand, the sensors directly send out the temperature data, MSP430F149 has the advantage of ultra-low-power and high degree of integration. Using msp430F149, the multi-branch multi-point temperature measurement system is powerful, simple structure, high reliability, strong anti-interference capability. The client software is user-friendly and easy to use, it is designed in Microsoft Visual C+ +6.0 environment. The monitoring system is able to complete a total of 4 branches of the 40-point temperature measurements in real-time remote monitoring. (authors)

To Boldly Go: Practical Career Advice for Young Scientists

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Fiske, P.

1998-05-01

Young scientists in nearly every field are finding the job market of the 1990's a confusing and frustrating place. Ph.D. supply is far larger than that needed to fill entry-level positions in "traditional" research careers. More new Ph.D. and Master's degree holders are considering a wider range of careers in and out of science, but feel ill-prepared and uninformed about their options. Some feel their Ph.D. training has led them to a dead-end. I present a thorough and practical overview to the process of career planning and job hunting in the 1990's, from the perspective of a young scientist. I cover specific steps that young scientists can take to broaden their horizons, strengthen their skills, and present their best face to potential employers. An important part of this is the realization that most young scientists possess a range of valuable "transferable skills" that are highly sought after by employers in and out of science. I will summarize the specifics of job hunting in the 90's, including informational interviewing, building your network, developing a compelling CV and resume, cover letters, interviewing, based on my book "To Boldly Go: A Practical Career Guide for Scientists". I will also identify other resources available for young scientists. Finally, I will highlight individual stories of Ph.D.-trained scientists who have found exciting and fulfilling careers outside the "traditional" world of academia.

Back pain in seniors: the Back pain Outcomes using Longitudinal Data (BOLD) cohort baseline data.

Science.gov (United States)

Jarvik, Jeffrey G; Comstock, Bryan A; Heagerty, Patrick J; Turner, Judith A; Sullivan, Sean D; Shi, Xu; Nerenz, David R; Nedeljkovic, Srdjan S; Kessler, Larry; James, Kathryn; Friedly, Janna L; Bresnahan, Brian W; Bauer, Zoya; Avins, Andrew L; Deyo, Richard A

2014-04-23

Back pain represents a substantial burden globally, ranking first in a recent assessment among causes of years lived with disability. Though back pain is widely studied among working age adults, there are gaps with respect to basic descriptive epidemiology among seniors, especially in the United States. Our goal was to describe how pain, function and health-related quality of life vary by demographic and geographic factors among seniors presenting to primary care providers with new episodes of care for back pain. We examined baseline data from the Back pain Outcomes using Longitudinal Data (BOLD) registry, the largest inception cohort to date of seniors presenting to a primary care provider for back pain. The sample included 5,239 patients ≥ 65 years old with a new primary care visit for back pain at three integrated health systems (Northern California Kaiser-Permanente, Henry Ford Health System [Detroit], and Harvard Vanguard Medical Associates [Boston]). We examined differences in patient characteristics across healthcare sites and associations of patient sociodemographic and clinical characteristics with baseline patient-reported measures of pain, function, and health-related quality of life. Patients differed across sites in demographic and other characteristics. The Detroit site had more African-American patients (50%) compared with the other sites (7-8%). The Boston site had more college graduates (68%) compared with Detroit (20%). Female sex, lower educational status, African-American race, and older age were associated with worse functional disability as measured by the Roland-Morris Disability Questionnaire. Except for age, these factors were also associated with worse pain. Baseline pain and functional impairment varied substantially with a number of factors in the BOLD cohort. Healthcare site was an important factor. After controlling for healthcare site, lower education, female sex, African-American race, and older age were associated with worse

P300 amplitude variation is related to ventral striatum BOLD response during gain and loss anticipation: an EEG and fMRI experiment.

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Pfabigan, Daniela M; Seidel, Eva-Maria; Sladky, Ronald; Hahn, Andreas; Paul, Katharina; Grahl, Arvina; Küblböck, Martin; Kraus, Christoph; Hummer, Allan; Kranz, Georg S; Windischberger, Christian; Lanzenberger, Rupert; Lamm, Claus

2014-08-01

The anticipation of favourable or unfavourable events is a key component in our daily life. However, the temporal dynamics of anticipation processes in relation to brain activation are still not fully understood. A modified version of the monetary incentive delay task was administered during separate functional magnetic resonance imaging (fMRI) and electroencephalogram (EEG) sessions in the same 25 participants to assess anticipatory processes with a multi-modal neuroimaging set-up. During fMRI, gain and loss anticipation were both associated with heightened activation in ventral striatum and reward-related areas. EEG revealed most pronounced P300 amplitudes for gain anticipation, whereas CNV amplitudes distinguished neutral from gain and loss anticipation. Importantly, P300, but not CNV amplitudes, were correlated to neural activation in the ventral striatum for both gain and loss anticipation. Larger P300 amplitudes indicated higher ventral striatum blood oxygen level dependent (BOLD) response. Early stimulus evaluation processes indexed by EEG seem to be positively related to higher activation levels in the ventral striatum, indexed by fMRI, which are usually associated with reward processing. The current results, however, point towards a more general motivational mechanism processing salient stimuli during anticipation. Copyright © 2014. Published by Elsevier Inc.

The use of 18F-fluoride and 18F-FDG PET scans to assess fracture healing in a rat femur model

International Nuclear Information System (INIS)

Hsu, W.K.; Feeley, B.T.; Krenek, L.; Stout, D.B.; Chatziioannou, A.F.; Lieberman, J.R.

2007-01-01

Currently available diagnostic techniques can be unreliable in the diagnosis of delayed fracture healing in certain clinical situations, which can lead to increased complication rates and costs to the health care system. This study sought to determine the utility of positron emission tomography (PET) scanning with 18 F-fluoride ion, which localizes in regions of high osteoblastic activity, and 18 F-fluorodeoxyglucose (FDG), an indicator of cellular glucose metabolism, in assessing bone healing in a rat femur fracture model. Fractures were created in the femurs of immunocompetent rats. Animals in group I had a fracture produced via a manual three-point bending technique. Group II animals underwent a femoral osteotomy with placement of a 2-mm silastic spacer at the fracture site. Fracture healing was assessed with plain radiographs, 18 F-fluoride, and 18 F-FDG PET scans at 1, 2, 3, and 4-week time points after surgery. Femoral specimens were harvested for histologic analysis and manual testing of torsional and bending strength 4 weeks after surgery. All fractures in group I revealed abundant callus formation and bone healing, while none of the nonunion femurs were healed via assessment with manual palpation, radiographic, and histologic evaluation at the 4-week time point. 18 F-fluoride PET images of group I femurs at successive 1-week intervals revealed progressively increased signal uptake at the union site during fracture repair. In contrast, minimal tracer uptake was seen at the fracture sites in group II at all time points after surgery. Data analysis revealed statistically significant differences in mean signal intensity between groups I and II at each weekly interval. No significant differences between the two groups were seen using 18 F-FDG PET imaging at any time point. This study suggests that 18 F-fluoride PET imaging, which is an indicator of osteoblastic activity in vivo, can identify fracture nonunions at an early time point and may have a role in the

The use of 18F-fluoride and 18F-FDG PET scans to assess fracture healing in a rat femur model

Science.gov (United States)

Hsu, W. K.; Feeley, B. T.; Krenek, L.; Stout, D. B.; Chatziioannou, A. F.; Lieberman, J. R.

2011-01-01

Purpose Currently available diagnostic techniques can be unreliable in the diagnosis of delayed fracture healing in certain clinical situations, which can lead to increased complication rates and costs to the health care system. This study sought to determine the utility of positron emission tomography (PET) scanning with 18F-fluoride ion, which localizes in regions of high osteoblastic activity, and 18F-fluorodeoxyglucose (FDG), an indicator of cellular glucose metabolism, in assessing bone healing in a rat femur fracture model. Methods Fractures were created in the femurs of immuno-competent rats. Animals in group I had a fracture produced via a manual three-point bending technique. Group II animals underwent a femoral osteotomy with placement of a 2-mm silastic spacer at the fracture site. Fracture healing was assessed with plain radiographs, 18F-fluoride, and 18F-FDG PET scans at 1, 2, 3, and 4-week time points after surgery. Femoral specimens were harvested for histologic analysis and manual testing of torsional and bending strength 4 weeks after surgery. Results All fractures in group I revealed abundant callus formation and bone healing, while none of the nonunion femurs were healed via assessment with manual palpation, radiographic, and histologic evaluation at the 4-week time point. 18F-fluoride PET images of group I femurs at successive 1-week intervals revealed progressively increased signal uptake at the union site during fracture repair. In contrast, minimal tracer uptake was seen at the fracture sites in group II at all time points after surgery. Data analysis revealed statistically significant differences in mean signal intensity between groups I and II at each weekly interval. No significant differences between the two groups were seen using 18F-FDG PET imaging at any time point. Conclusion This study suggests that 18F-fluoride PET imaging, which is an indicator of osteoblastic activity in vivo, can identify fracture nonunions at an early time point

18O isotopic characterisation of non-point source contributed heavy metals (Zn and Cu) contamination of groundwater

International Nuclear Information System (INIS)

Datta, P.S.; Manjaiah, K.M.; Tyagi, S.K.

1999-01-01

In many urbanised areas, fast depletion and severe degradation of the of groundwater resource with contaminants such as nitrate, fluoride, and heavy metals is a common phenomenon, resulting in zonal disparity in fresh water availability. Therefore, for protection of groundwater from pollution and depletion, it is a matter of concern for the planners and decision makers to clearly characterise the sources of contamination and to search for an alternative approach for groundwater development and management. In this context, a new approach is presented here, based on monitoring of 18 O stable isotopic and heavy metals composition of groundwater, to clearly characterise non-point source contributed heavy metals pollution of groundwater in northern parts of Delhi area. In the investigated area, the Cu content in the groundwater ranges from 3-41 μg/l and Zn content ranges from 5-182 μg/l, showing considerable variation from location to location as well as within the small parts of a location. Wide variation in the 18 O stable isotope content of groundwater (δ value of -5.7 per mille to -8.5 per mille) is due to significant variation in the δ 18 O-contents of rainfall with space and time, as well as intensity and distribution of rainfall. Enrichment in 18 O composition with increasing Cu and Zn levels in groundwater suggest that infiltration of rain water, irrigation water and surface run-off water from the surrounding farm lands, along with agrochemicals and other salts present in the soil, to be the main processes causing groundwater contamination. The concentration of Cu and Zn in groundwater vary spatially, due to different degrees of evaporation/recharge, amounts of fertiliser applied and wastes disposed, adsorption/dispersion of species in the soils and lateral mixing of groundwater. Two opposite mechanisms adsorption and redistribution of infiltrating water along with Zn and Cu species in the soil zone are likely to affect the movement of the Zn and Cu species

33 CFR 161.18 - Reporting requirements.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Reporting requirements. 161.18 Section 161.18 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... call. H HOTEL Date, time and point of entry system Entry time expressed as in (B) and into the entry...

Higher frequency network activity flow predicts lower frequency node activity in intrinsic low-frequency BOLD fluctuations.

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Bajaj, Sahil; Adhikari, Bhim Mani; Dhamala, Mukesh

2013-01-01

The brain remains electrically and metabolically active during resting conditions. The low-frequency oscillations (LFO) of the blood oxygen level-dependent (BOLD) signal of functional magnetic resonance imaging (fMRI) coherent across distributed brain regions are known to exhibit features of this activity. However, these intrinsic oscillations may undergo dynamic changes in time scales of seconds to minutes during resting conditions. Here, using wavelet-transform based time-frequency analysis techniques, we investigated the dynamic nature of default-mode networks from intrinsic BOLD signals recorded from participants maintaining visual fixation during resting conditions. We focused on the default-mode network consisting of the posterior cingulate cortex (PCC), the medial prefrontal cortex (mPFC), left middle temporal cortex (LMTC) and left angular gyrus (LAG). The analysis of the spectral power and causal flow patterns revealed that the intrinsic LFO undergo significant dynamic changes over time. Dividing the frequency interval 0 to 0.25 Hz of LFO into four intervals slow-5 (0.01-0.027 Hz), slow-4 (0.027-0.073 Hz), slow-3 (0.073-0.198 Hz) and slow-2 (0.198-0.25 Hz), we further observed significant positive linear relationships of slow-4 in-out flow of network activity with slow-5 node activity, and slow-3 in-out flow of network activity with slow-4 node activity. The network activity associated with respiratory related frequency (slow-2) was found to have no relationship with the node activity in any of the frequency intervals. We found that the net causal flow towards a node in slow-3 band was correlated with the number of fibers, obtained from diffusion tensor imaging (DTI) data, from the other nodes connecting to that node. These findings imply that so-called resting state is not 'entirely' at rest, the higher frequency network activity flow can predict the lower frequency node activity, and the network activity flow can reflect underlying structural

Greater BOLD variability in older compared with younger adults during audiovisual speech perception.

Directory of Open Access Journals (Sweden)

Sarah H Baum

Full Text Available Older adults exhibit decreased performance and increased trial-to-trial variability on a range of cognitive tasks, including speech perception. We used blood oxygen level dependent functional magnetic resonance imaging (BOLD fMRI to search for neural correlates of these behavioral phenomena. We compared brain responses to simple speech stimuli (audiovisual syllables in 24 healthy older adults (53 to 70 years old and 14 younger adults (23 to 39 years old using two independent analysis strategies: region-of-interest (ROI and voxel-wise whole-brain analysis. While mean response amplitudes were moderately greater in younger adults, older adults had much greater within-subject variability. The greatly increased variability in older adults was observed for both individual voxels in the whole-brain analysis and for ROIs in the left superior temporal sulcus, the left auditory cortex, and the left visual cortex. Increased variability in older adults could not be attributed to differences in head movements between the groups. Increased neural variability may be related to the performance declines and increased behavioral variability that occur with aging.

Monitoring of anti-cancer treatment with (18)F-FDG and (18)F-FLT PET

DEFF Research Database (Denmark)

Jensen, Mette Munk; Kjaer, Andreas

2015-01-01

treatment effect early in a treatment course and by that to stratify patients into responders and non-responders. With 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) and 3'-deoxy-3'-[(18)F]fluorothymidine((18)F-FLT) two of the cancer hallmarks, altered energy metabolism and increased cell proliferation, can......Functional imaging of solid tumors with positron emission tomography (PET) imaging is an evolving field with continuous development of new PET tracers and discovery of new applications for already implemented PET tracers. During treatment of cancer patients, a general challenge is to measure...... be visualized and quantified non-invasively by PET. With (18)F-FDG and (18)F-FLT PET changes in energy metabolism and cell proliferation can thereby be determined after initiation of cancer treatment in both clinical and pre-clinical studies in order to predict, at an early time-point, treatment response...

Assessment of the usefulness of the standardized uptake values and the radioactivity levels for the preoperative diagnosis of thyroid cancer measured by using 18F-FDG PET/CT dual-time-point imaging

Science.gov (United States)

Lee, Hyeon-Guck; Hong, Seong-Jong; Cho, Jae-Hwan; Han, Man-Seok; Kim, Tae-Hyung; Lee, Ik-Han

2013-02-01

The purpose of this study was to assess and compare the changes in the SUV (standardized uptake value), the 18F-FDG (18F-fluorodeoxyglucose) uptake pattern, and the radioactivity level for the diagnosis of thyroid cancer via dual-time-point 18F-FDG PET/CT (positron emission tomographycomputed tomography) imaging. Moreover, the study aimed to verify the usefulness and significance of SUV values and radioactivity levels to discriminate tumor malignancy. A retrospective analysis was performed on 40 patients who received 18F-FDG PET/CT for thyroid cancer as a primary tumor. To set the background, we compared changes in values by calculating the dispersion of scattered rays in the neck area and the lung apex, and by comparing the mean and SD (standard deviation) values of the maxSUV and the radioactivity levels. According to the statistical analysis of the changes in 18F-FDG uptake for the diagnosis of thyroid cancer, a high similarity was observed with the coefficient of determination being R2 = 0.939, in the SUVs and the radioactivity levels. Moreover, similar results were observed in the assessment of tumor malignancy using dual-time-point. The quantitative analysis method for assessing tumor malignancy using radioactivity levels was neither specific nor discriminative compared to the semi-quantitative analysis method.

Mapping of the brain hemodynamic responses to sensorimotor stimulation in a rodent model: A BOLD fMRI study.

Directory of Open Access Journals (Sweden)

Salem Boussida

Full Text Available Blood Oxygenation Level Dependent functional MRI (BOLD fMRI during electrical paw stimulation has been widely used in studies aimed at the understanding of the somatosensory network in rats. However, despite the well-established anatomical connections between cortical and subcortical structures of the sensorimotor system, most of these functional studies have been concentrated on the cortical effects of sensory electrical stimulation. BOLD fMRI study of the integration of a sensorimotor input across the sensorimotor network requires an appropriate methodology to elicit functional activation in cortical and subcortical areas owing to the regional differences in both neuronal and vascular architectures between these brain regions. Here, using a combination of low level anesthesia, long pulse duration of the electrical stimulation along with improved spatial and temporal signal to noise ratios, we provide a functional description of the main cortical and subcortical structures of the sensorimotor rat brain. With this calibrated fMRI protocol, unilateral non-noxious sensorimotor electrical hindpaw stimulation resulted in robust positive activations in the contralateral sensorimotor cortex and bilaterally in the sensorimotor thalamus nuclei, whereas negative activations were observed bilaterally in the dorsolateral caudate-putamen. These results demonstrate that, once the experimental setup allowing necessary spatial and temporal signal to noise ratios is reached, hemodynamic changes related to neuronal activity, as preserved by the combination of a soft anesthesia with a soft muscle relaxation, can be measured within the sensorimotor network. Moreover, the observed responses suggest that increasing pulse duration of the electrical stimulus adds a proprioceptive component to the sensory input that activates sensorimotor network in the brain, and that these activation patterns are similar to those induced by digits paw's movements. These findings may

Modulation of cognitive control levels via manipulation of saccade trial-type probability assessed with event-related BOLD fMRI.

Science.gov (United States)

Pierce, Jordan E; McDowell, Jennifer E

2016-02-01

Cognitive control supports flexible behavior adapted to meet current goals and can be modeled through investigation of saccade tasks with varying cognitive demands. Basic prosaccades (rapid glances toward a newly appearing stimulus) are supported by neural circuitry, including occipital and posterior parietal cortex, frontal and supplementary eye fields, and basal ganglia. These trials can be contrasted with complex antisaccades (glances toward the mirror image location of a stimulus), which are characterized by greater functional magnetic resonance imaging (MRI) blood oxygenation level-dependent (BOLD) signal in the aforementioned regions and recruitment of additional regions such as dorsolateral prefrontal cortex. The current study manipulated the cognitive demands of these saccade tasks by presenting three rapid event-related runs of mixed saccades with a varying probability of antisaccade vs. prosaccade trials (25, 50, or 75%). Behavioral results showed an effect of trial-type probability on reaction time, with slower responses in runs with a high antisaccade probability. Imaging results exhibited an effect of probability in bilateral pre- and postcentral gyrus, bilateral superior temporal gyrus, and medial frontal gyrus. Additionally, the interaction between saccade trial type and probability revealed a strong probability effect for prosaccade trials, showing a linear increase in activation parallel to antisaccade probability in bilateral temporal/occipital, posterior parietal, medial frontal, and lateral prefrontal cortex. In contrast, antisaccade trials showed elevated activation across all runs. Overall, this study demonstrated that improbable performance of a typically simple prosaccade task led to augmented BOLD signal to support changing cognitive control demands, resulting in activation levels similar to the more complex antisaccade task. Copyright © 2016 the American Physiological Society.

Synthesis and preclinical evaluation of the choline transport tracer deshydroxy-[18F]fluorocholine ([18F]dOC)

International Nuclear Information System (INIS)

Henriksen, G.; Herz, M.; Hauser, A.; Schwaiger, M.; Wester, H.-J.

2004-01-01

11 C-labeled choline ([ 11 C]CHO) and 18 F-fluorinated choline analogues have been demonstrated to be valuable tracers for in vivo imaging of neoplasms by means of positron emission tomography (PET). The objective of the present study was to evaluate whether deshydroxy-[ 18 F]fluorocholine, ([ 18 F]dOC), a non-metabolizable [ 18 F]fluorinated choline analogue, can serve as a surrogate for cholines that are able to be phosphorylated and thus allow PET-imaging solely by addressing the choline transport system. The specificity of uptake of [ 18 F]dOC was compared with that of [ 11 C]choline ([ 11 C]CHO) in cultured rat pancreatic carcinoma and PC-3 human prostate cancer cells in vitro. In addition, biodistribution of [ 18 F]dOC and [ 11 C]CHO was compared in AR42J- and PC-3 tumor bearing mice. The in vitro studies revealed that membrane transport of both compounds can be inhibited in a concentration dependent manner by similar concentrations of cold choline (IC 50 [ 18 F]dOC= 11 μM; IC 50 [ 11 C]CHO=13 μM. In vitro studies with PC-3 and AR42J cells revealed that the internalized fraction of [ 18 F]dOC after 5 min incubation time is comparable to that of [ 11 C]CHO, whereas the uptake of [ 11 C]CHO was superior after 20 min incubation time. As for [ 11 C]CHO, kidney and liver were also the primary sites of uptake for [ 18 F]dOC in vivo. Biodistribution data after simultaneous injection of both tracers into AR42J tumor bearing mice revealed slightly higher tumor uptake for [ 18 F]dOC at 10 min post-injection, whereas [ 11 C]CHO uptake was higher at later time points. In conclusion, [ 18 F]dOC is taken up into AR42J rat pancreatic carcinoma and PC-3 human prostate cancer cells by a choline specific transport system. Similar transport rates of [ 18 F]dOC and [ 11 C]CHO result in comparable cellular uptake levels at early time points. In contrast to [ 18 F]dOC, which is transported but not intracellularily trapped, the choline kinase substrate [ 11 C]CHO is transported

Temperature profiles from mechanical bathythermograph (MBT) casts from the USS BOLD in the Mediterranean Sea in support of the Fleet Observations of Oceanographic Data (FLOOD) project for 1955-08-25 (NODC Accession 5500036)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — MBT data were collected from the USS BOLD in support of the Fleet Observations of Oceanographic Data (FLOOD) project. Data were collected by US Navy; Ships of...

BOLD/VENTURE-4, Reactor Analysis System with Sensitivity and Burnup

International Nuclear Information System (INIS)

1998-01-01

1 - Description of program or function: The system of codes can be used to solve nuclear reactor core static neutronics and reactor history exposure problems. BOLD/VENTURE-4: First order perturbation and time-dependent sensitivity theories can be applied. Control rod positioning may be modeled explicitly and refueling treated with repositioning and recycle. Special capability is coded to model the continuously fueled core and to solve the importance and dominant harmonics problems. The modules of the code system are: VENTNEUT: VENTURE neutronics module; DRIVER and CONTRL: Control module; BURNER: Exposure calculation for reactor core analysis; FILEDTOR: File editor; INPROSER: Input processor; EXPOSURE: BURNER code module; REACRATE: Reaction rate calculation; CNTRODPO: Control rod positioning; FUELMANG: Fuel management positioning and accounting; PERTUBAT: Perturbation reactivity importance analyses; sensitivity analysis; DEPTHMOD: Static and time-dependent perturbation sensitivity analysis. The special processors are: DVENTR: Handles the input to the VENTURE module; DCMACR: Converts CITATION macroscopic cross sections to microscopic cross sections; DCRSPR: Produces input for the CROSPROS module; DUTLIN: Adds or replaces problem input data without exiting the program; DENMAN: Repositions fuel; DMISLY: Miscellaneous tasks. Standard interface files between modules are binary sequential files that follow a standardized format. VENTURE-PC: The microcomputer version is a subset of the mainframe version. The modules and special processors which are not part of VENTURE-PC are: REACRATE, CNTRODPO, PERTUBAT, FUELMANG, DEPTHMOD, DMISLY. 2 - method of solution: BOLD-VENTURE-4: The neutronics problems are solved by applying the multigroup diffusion theory representation of neutron transport applying an over-relaxation inner iteration, outer iteration scheme. Special modeling is used or source correction is done during iteration to solve importance and harmonics problems. No

Gridding Global δ 18Owater and Interpreting Core Top δ 18Oforam

Science.gov (United States)

Legrande, A. N.; Schmidt, G.

2004-05-01

Estimations of the oxygen isotope ratio in seawater (δ 18O water) traditionally have relied on regional δ 18O water to salinity relationships to convert seawater salinity into δ 18O water. This indirect method of determining δ 18O water is necessary since ?18Owater measurements are relatively sparse. We improve upon this process by constructing local δ 18O water to salinity curves using the Schmidt et al. (1999) global database of δ 18O water and salinity. We calculate local δ 18O water to salinity relationship on a 1x1 grid based on the closest database points to each grid box. Each ocean basin is analyzed separately, and each curve is processed to exclude outliers. These local relationships in combination with seawater salinity (Levitus, 1994) allow us to construct a global map of δ 18O water on a 1x1 grid. We combine seawater temperature (Levitus, 1994) with this dataset to predict δ 18O calcite on a 1x1 grid. These predicted values are then compared to previous compilations of core top δ 18O foram data for individual species of foraminifera. This comparison provides insight into the calcification habitats (as inferred by seawater temperature and salinity) of these species. Additionally, we compare the 1x1 grid of δ 18O water to preliminary output from the latest GISS coupled Atmosphere/Ocean GCM that tracks water isotopes through the hydrologic cycle. This comparison provides insight into possible model applications as a tool to aid in interpreting paleo-isotope data.

Trailing (L5) Neptune Trojans: 2004 KV18 and 2008 LC18

International Nuclear Information System (INIS)

Guan Pu; Zhou Liyong; Li Jian

2012-01-01

The population of Neptune Trojans is believed to be bigger than that of Jupiter Trojans and that of asteroids in the main belt, although only eight members of this distant asteroid swarm have been observed up to now. Six leading Neptune Trojans around the Lagrange point L 4 discovered earlier have been studied in detail, but two trailing ones found recently around the L 5 point, 2004 KV18 and 2008 LC18, have not yet been investigated. We report our investigations on the dynamical behaviors of these two new Neptune Trojans. Our calculations show that the asteroid 2004 KV18 is a temporary Neptune Trojan. Most probably, it was captured into the trailing Trojan cloud no earlier than 2.03 × 10 5 yr ago, and it will not maintain this position later than 1.65 × 10 5 yr in the future. Based on the statistics from our orbital simulations, we argue that this object is more like a scattered Kuiper belt object. By contrast, the orbit of 2008 LC18 is much more stable. Among the clone orbits spreading within the orbital uncertainties, a considerable portion of clones may survive on the L 5 tadpole orbits for 4 Gyr. The strong dependence of the stability on the semimajor axis and resonant angle suggests that further observations are badly required to constrain the orbit in the stable region. We also discuss the implications of the existence and dynamics of these two trailing Trojans over the history of the solar system.

Exploiting magnetic resonance angiography imaging improves model estimation of BOLD signal.

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Zhenghui Hu

Full Text Available The change of BOLD signal relies heavily upon the resting blood volume fraction ([Formula: see text] associated with regional vasculature. However, existing hemodynamic data assimilation studies pretermit such concern. They simply assign the value in a physiologically plausible range to get over ill-conditioning of the assimilation problem and fail to explore actual [Formula: see text]. Such performance might lead to unreliable model estimation. In this work, we present the first exploration of the influence of [Formula: see text] on fMRI data assimilation, where actual [Formula: see text] within a given cortical area was calibrated by an MR angiography experiment and then was augmented into the assimilation scheme. We have investigated the impact of [Formula: see text] on single-region data assimilation and multi-region data assimilation (dynamic cause modeling, DCM in a classical flashing checkerboard experiment. Results show that the employment of an assumed [Formula: see text] in fMRI data assimilation is only suitable for fMRI signal reconstruction and activation detection grounded on this signal, and not suitable for estimation of unobserved states and effective connectivity study. We thereby argue that introducing physically realistic [Formula: see text] in the assimilation process may provide more reliable estimation of physiological information, which contributes to a better understanding of the underlying hemodynamic processes. Such an effort is valuable and should be well appreciated.

The Role of Oxytocin in Parenting and as Augmentative Pharmacotherapy: Critical Issues and Bold Conjectures.

Science.gov (United States)

van IJzendoorn, M H; Bakermans-Kranenburg, M J

2016-08-01

Despite the sometimes heated debate about the validity of human oxytocin studies, experimental oxytocin research with intranasal administration is a growing field with promising preliminary findings. The effects of intranasally administered oxytocin compared to placebo on brain neural activity have been supported in animal studies and in human studies of neural resting state. In several studies, oxytocin sniffs have been shown to lead to down-regulation of amygdala activation in response to infant attachment vocalisations. Meta-analytic evidence shows that oxytocin enhances the salience of (emotional) stimuli, lowers stress and arousal, and elevates empathic concern and tender care, in particular for offspring and in-group members. Less firm evidence points at the amnestic effects of oxytocin. We also note that the average effect sizes of oxytocin experiments are small to modest, and that most studies include a small number of subjects and thus are seriously underpowered, which implies a high risk for publication bias and nonreplicability. Nevertheless, we argue that the power of within-subjects experiments with oxytocin has been underestimated. Much more work is needed, however, to create a firm knowledge base of the neural and behavioural effects of oxytocin. Human oxytocin research is still taking place in the context of discovery, in which bold conjectures are being generated. In the context of justification, these conjectures should subsequently be subjected to stringent attempts at refutations before we jump to theoretical or clinical conclusions. For this context of justification, we propose a multisite multiple replications project on the social stimuli salience enhancing effect of oxytocin. Clinical application of oxytocin is premature. Meta-analytically, the use of oxytocin in clinical groups tends to show only effectiveness in changing symptomatology in individuals with autism spectrum disorders but, even then, it is not yet a validated therapy and its

Linear Discriminant Analysis achieves high classification accuracy for the BOLD fMRI response to naturalistic movie stimuli.

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Hendrik eMandelkow

2016-03-01

Full Text Available Naturalistic stimuli like movies evoke complex perceptual processes, which are of great interest in the study of human cognition by functional MRI (fMRI. However, conventional fMRI analysis based on statistical parametric mapping (SPM and the general linear model (GLM is hampered by a lack of accurate parametric models of the BOLD response to complex stimuli. In this situation, statistical machine-learning methods, a.k.a. multivariate pattern analysis (MVPA, have received growing attention for their ability to generate stimulus response models in a data-driven fashion. However, machine-learning methods typically require large amounts of training data as well as computational resources. In the past this has largely limited their application to fMRI experiments involving small sets of stimulus categories and small regions of interest in the brain. By contrast, the present study compares several classification algorithms known as Nearest Neighbour (NN, Gaussian Naïve Bayes (GNB, and (regularised Linear Discriminant Analysis (LDA in terms of their classification accuracy in discriminating the global fMRI response patterns evoked by a large number of naturalistic visual stimuli presented as a movie.Results show that LDA regularised by principal component analysis (PCA achieved high classification accuracies, above 90% on average for single fMRI volumes acquired 2s apart during a 300s movie (chance level 0.7% = 2s/300s. The largest source of classification errors were autocorrelations in the BOLD signal compounded by the similarity of consecutive stimuli. All classifiers performed best when given input features from a large region of interest comprising around 25% of the voxels that responded significantly to the visual stimulus. Consistent with this, the most informative principal components represented widespread distributions of co-activated brain regions that were similar between subjects and may represent functional networks. In light of these

Development of a parallel zoomed EVI sequence for high temporal resolution analysis of the BOLD response

International Nuclear Information System (INIS)

Rabrait, C.

2006-01-01

The hemodynamic impulse response to any short stimulus typically lasts around 20 seconds. Thus, the detection of the Blood Oxygenation Level Dependent (BOLD) effect is usually performed using a 2D Echo Planar Imaging (EPI) sequence, with repetition times on the order of 1 or 2 seconds. This temporal resolution is generally enough for detection purposes. Nevertheless, when trying to accurately estimate the hemodynamic response functions (HRF), higher scanning rates represent a real advantage. Thus, in order to reach a temporal resolution around 200 ms, we developed a new acquisition method, based on Echo Volumar Imaging and 2D parallel acquisition (1). Echo Volumar Imaging (EVI) has been proposed in 1977 by Mansfield (2). EVI intrinsically possesses a lot of advantages for functional neuroimaging, as a 3 D single shot acquisition method. Nevertheless, to date, only a few applications have been reported (3, 4). Actually, very restricting hardware requirements make EVI difficult to perform in satisfactory experimental conditions, even today. The critical point in EVI is the echo train duration, which is longer than in EPI, due to 3D acquisition. Indeed, at equal field of view and spatial resolutions, EVI echo train duration must be approximately equal to EPI echo train duration multiplied by the number of slices acquired in EPI. Consequently, EVI is much more sensitive than EPI to geometric distortions, which are related to phase errors, and also to signal losses, which are due to long echo times (TE). Thus, a first improvement has been brought by 'zoomed' or 'localized' EVI (5), which allows to focus on a small volume of interest and thus limit echo train durations compared to full FOV acquisitions.To reduce echo train durations, we chose to apply parallel acquisition. Moreover, since EVI is a 3D acquisition method, we are able to perform parallel acquisition and SENSE reconstruction along the two phase directions (6). The R = 4 under-sampling consists in the

Using Python to Program LEGO MINDSTORMS® Robots: The PyNXC Project

Directory of Open Access Journals (Sweden)

2010-04-01

Full Text Available

Helvetica; margin: 0px">Helvetica, sans-serif" size="2" class="Apple-style-span">Helvetica" size="3" class="Apple-style-span">

 

Correcting for Blood Arrival Time in Global Mean Regression Enhances Functional Connectivity Analysis of Resting State fMRI-BOLD Signals.

Science.gov (United States)

Erdoğan, Sinem B; Tong, Yunjie; Hocke, Lia M; Lindsey, Kimberly P; deB Frederick, Blaise

2016-01-01

Resting state functional connectivity analysis is a widely used method for mapping intrinsic functional organization of the brain. Global signal regression (GSR) is commonly employed for removing systemic global variance from resting state BOLD-fMRI data; however, recent studies have demonstrated that GSR may introduce spurious negative correlations within and between functional networks, calling into question the meaning of anticorrelations reported between some networks. In the present study, we propose that global signal from resting state fMRI is composed primarily of systemic low frequency oscillations (sLFOs) that propagate with cerebral blood circulation throughout the brain. We introduce a novel systemic noise removal strategy for resting state fMRI data, "dynamic global signal regression" (dGSR), which applies a voxel-specific optimal time delay to the global signal prior to regression from voxel-wise time series. We test our hypothesis on two functional systems that are suggested to be intrinsically organized into anticorrelated networks: the default mode network (DMN) and task positive network (TPN). We evaluate the efficacy of dGSR and compare its performance with the conventional "static" global regression (sGSR) method in terms of (i) explaining systemic variance in the data and (ii) enhancing specificity and sensitivity of functional connectivity measures. dGSR increases the amount of BOLD signal variance being modeled and removed relative to sGSR while reducing spurious negative correlations introduced in reference regions by sGSR, and attenuating inflated positive connectivity measures. We conclude that incorporating time delay information for sLFOs into global noise removal strategies is of crucial importance for optimal noise removal from resting state functional connectivity maps.

Value of dual-time-point 18FDG PET-CT imaging on involved-field radiotherapy for hilar and mediastinal metastatic lymph nodes in non-small cell lung cancer

International Nuclear Information System (INIS)

Hu Man; Sun Xindong; Liu Ningbo; Gong Heyi; Fu Zheng; Ma Li; Li Xinke; Xu Xiaoqing; Yu Jinming

2008-01-01

Objective: To discuss the value of dual-time-point 18 FDG PET-CT imaging on involved-field radiotherapy for hilar and mediastinal metastatic lymph nodes in patients with non-small cell lung cancer (NSCLC). Methods: Fifty-four patients with NSCLC were included in this analysis, including 34 men and 20 women with mean age of 59 (34-76) years. Two sequential PET-CT scans given 3-5 days before surgery were standard single-time-point imaging for the whole body and delayed imaging for the thorax. The pathologic data were used as golden standard to determine the difference between the standard single-time-point and dual-time-point PET-CT imaging in the definition of gross target volume (GTV) of involved-field radiotherapy for metastatic lymph nodes. Results: For hilar metastatic lymph nodes, the GTV defined by single-time-point imaging was consistent with pathologic GTV in 21 patients (39%), comparing with 31 patients (57%) by dual-time-point imaging. Using pathologic data as golden standard, GTV alteration defined by single-time-point imaging had statistically significant difference comparing with that defined by dual-time-point imaging( =519.00, P=0.023). For mediastinal metastatic lymph nodes, the GTV defined by single-time-point imaging was consistent with pathologic GTV in 30 patients (56%), comparing with 36 patients (67%) by dual-time-point imaging. Using pathologic data as golden standard, GTV alteration defined by single-time-point imaging had no statistically significant difference comparing with that defined by dual-time-point imaging (u= 397.50, P=0.616). Conclusions: For patients with NSCLC receiving involved-field radiotherapy, GTV definition for hilar and mediastinal metastatic lymph nodes by dual-time-point imaging is more consistent with that by pathologic data. Dual-time-point imaging has a larger value in terms of target delineation for hilar and mediastinal metastatic lymph nodes. (authors)

33 CFR 167.452 - In the Santa Barbara Channel: Between Point Conception and Point Arguello.

Science.gov (United States)

2010-07-01

....452 In the Santa Barbara Channel: Between Point Conception and Point Arguello. (a) A separation zone... 120°30.16′ W. 34°18.90′ N 120°30.96′ W. 34°25.70′ N 120°51.81′ W. 34°23.75′ N 120°52.51′ W. (b) A traffic lane for westbound traffic is established between the separation zone and a line connecting the...

BOLD data representing activation and connectivity for rare no-go versus frequent go cues

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Harma Meffert

2016-06-01

Full Text Available The neural circuitry underlying response control is often studied using go/no-go tasks, in which participants are required to respond as fast as possible to go cues and withhold from responding to no-go stimuli. In the current task, response control was studied using a fully counterbalanced design in which blocks with a low frequency of no-go cues (75% go, 25% no-go were alternated with blocks with a low frequency of go cues (25% go, 75% no-go; see also “Segregating attention from response control when performing a motor inhibition task: Segregating attention from response control” [1]. We applied a whole brain corrected, paired t-test to the data assessing for regions differentially activated by low frequency no-go cues relative to high frequency go cues. In addition, we conducted a generalized psychophysiological interaction analysis on the data using a right inferior frontal gyrus seed region. This region was identified through the BOLD response t-test and was chosen because right inferior gyrus is highly implicated in response inhibition.

A Comparison of Product Realization Frameworks

Science.gov (United States)

1993-10-01

software (integrated FrameMaker ). Also included are BOLD for on-line documentation delivery, printer/plotter support, and 18 network licensing support. AMPLE...are built with DSS. Documentation tools include an on-line information system (BOLD), text editing (Notepad), word processing (integrated FrameMaker ...within an application. FrameMaker is fully integrated with the Falcon Framework to provide consistent documentation capabilities within engineering

Continuous EEG-fMRI in Pre-Surgical Evaluation of a Patient with Symptomatic Seizures: Bold Activation Linked to Interictal Epileptic Discharges Caused by Cavernoma.

Science.gov (United States)

Avesani, M; Formaggio, E; Milanese, F; Baraldo, A; Gasparini, A; Cerini, R; Bongiovanni, L G; Pozzi Mucelli, R; Fiaschi, A; Manganotti, P

2008-04-07

We used continuous electroencephalography-functional magnetic resonance imaging (EEG-fMRI) to identify the linkage between the "epileptogenic" and the "irritative" area in a patient with symptomatic epilepsy (cavernoma, previously diagnosed and surgically treated), i.e. a patient with a well known "epileptogenic area", and to increase the possibility of a non invasive pre-surgical evaluation of drug-resistant epilepsies. A compatible MRI system was used (EEG with 29 scalp electrodes and two electrodes for ECG and EMG) and signals were recorded with a 1.5 Tesla MRI scanner. After the recording session and MRI artifact removal, EEG data were analyzed offline and used as paradigms in fMRI study. Activation (EEG sequences with interictal slow-spiked-wave activity) and rest (sequences of normal EEG) conditions were compared to identify the potential resulting focal increase in BOLD signal and to consider if this is spatially linked to the interictal focus used as a paradigm and to the lesion. We noted an increase in the BOLD signal in the left neocortical temporal region, laterally and posteriorly to the poro-encephalic cavity (residual of cavernoma previously removed), that is around the "epileptogenic area". In our study "epileptogenic" and "irritative" areas were connected with each other. Combined EEG-fMRI may become routine in clinical practice for a better identification of an irritative and lesional focus in patients with symptomatic drug-resistant epilepsy.

BOLD responses in somatosensory cortices better reflect heat sensation than pain.

Science.gov (United States)

Moulton, Eric A; Pendse, Gautam; Becerra, Lino R; Borsook, David

2012-04-25

The discovery of cortical networks that participate in pain processing has led to the common generalization that blood oxygen level-dependent (BOLD) responses in these areas indicate the processing of pain. Physical stimuli have fundamental properties that elicit sensations distinguishable from pain, such as heat. We hypothesized that pain intensity coding may reflect the intensity coding of heat sensation during the presentation of thermal stimuli during fMRI. Six 3T fMRI heat scans were collected for 16 healthy subjects, corresponding to perceptual levels of "low innocuous heat," "moderate innocuous heat," "high innocuous heat," "low painful heat," "moderate painful heat," and "high painful heat" delivered by a contact thermode to the face. Subjects rated pain and heat intensity separately after each scan. A general linear model analysis detected different patterns of brain activation for the different phases of the biphasic response to heat. During high painful heat, the early phase was associated with significant anterior insula and anterior cingulate cortex activation. Persistent responses were detected in the right dorsolateral prefrontal cortex and inferior parietal lobule. Only the late phase showed significant correlations with perceptual ratings. Significant heat intensity correlated activation was identified in contralateral primary and secondary somatosensory cortices, motor cortex, and superior temporal lobe. These areas were significantly more related to heat ratings than pain. These results indicate that heat intensity is encoded by the somatosensory cortices, and that pain evaluation may either arise from multimodal evaluative processes, or is a distributed process.

Ratio of dopamine synthesis capacity to D2 receptor availability in ventral striatum correlates with central processing of affective stimuli

International Nuclear Information System (INIS)

Kienast, Thorsten; Rapp, Michael; Siessmeier, Thomas; Buchholz, Hans G.; Schreckenberger, Mathias; Wrase, Jana; Heinz, Andreas; Braus, Dieter F.; Smolka, Michael N.; Mann, Karl; Roesch, Frank; Cumming, Paul; Gruender, Gerhard; Bartenstein, Peter

2008-01-01

Dopaminergic neurotransmission in the ventral striatum may interact with limbic processing of affective stimuli, whereas dorsal striatal dopaminergic neurotransmission can affect habitual processing of emotionally salient stimuli in the pre-frontal cortex. We investigated the dopaminergic neurotransmission in the ventral and dorsal striatum with respect to central processing of affective stimuli in healthy subjects. Subjects were investigated with positron emission tomography and [ 18 F]DOPA for measurements of dopamine synthesis capacity and [ 18 F]DMFP for estimation of dopamine D2 receptor binding potential. Functional magnetic resonance imaging was used to assess the blood-oxygen-level-dependent (BOLD) response to affective pictures, which was correlated with the ratio of [ 18 F]DOPA net influx constant K in app /[ 18 F]DMFP-binding potential (BP N D) in the ventral and dorsal striatum. The magnitude of the ratio in the ventral striatum was positively correlated with BOLD signal increases elicited by negative versus neutral pictures in the right medial frontal gyrus (BA10), right inferior parietal lobe and left post-central gyrus. In the dorsal striatum, the ratio was positively correlated with BOLD signal activation elicited by negative versus neutral stimuli in the left post-central gyrus. The BOLD signal elicited by positive versus neutral stimuli in the superior parietal gyrus was positively correlated with the dorsal and ventral striatal ratio. The correlations of the ratio in the ventral and dorsal striatum with processing of affective stimuli in the named cortical regions support the hypothesis that dopamine transmission in functional divisions of the striatum modulates processing of affective stimuli in specific cortical areas. (orig.)

Distinct BOLD fMRI Responses of Capsaicin-Induced Thermal Sensation Reveal Pain-Related Brain Activation in Nonhuman Primates.

Directory of Open Access Journals (Sweden)

Abu Bakar Ali Asad

Full Text Available Approximately 20% of the adult population suffer from chronic pain that is not adequately treated by current therapies, highlighting a great need for improved treatment options. To develop effective analgesics, experimental human and animal models of pain are critical. Topically/intra-dermally applied capsaicin induces hyperalgesia and allodynia to thermal and tactile stimuli that mimics chronic pain and is a useful translation from preclinical research to clinical investigation. Many behavioral and self-report studies of pain have exploited the use of the capsaicin pain model, but objective biomarker correlates of the capsaicin augmented nociceptive response in nonhuman primates remains to be explored.Here we establish an aversive capsaicin-induced fMRI model using non-noxious heat stimuli in Cynomolgus monkeys (n = 8. BOLD fMRI data were collected during thermal challenge (ON:20 s/42°C; OFF:40 s/35°C, 4-cycle at baseline and 30 min post-capsaicin (0.1 mg, topical, forearm application. Tail withdrawal behavioral studies were also conducted in the same animals using 42°C or 48°C water bath pre- and post- capsaicin application (0.1 mg, subcutaneous, tail.Group comparisons between pre- and post-capsaicin application revealed significant BOLD signal increases in brain regions associated with the 'pain matrix', including somatosensory, frontal, and cingulate cortices, as well as the cerebellum (paired t-test, p<0.02, n = 8, while no significant change was found after the vehicle application. The tail withdrawal behavioral study demonstrated a significant main effect of temperature and a trend towards capsaicin induced reduction of latency at both temperatures.These findings provide insights into the specific brain regions involved with aversive, 'pain-like', responses in a nonhuman primate model. Future studies may employ both behavioral and fMRI measures as translational biomarkers to gain deeper understanding of pain processing and evaluate

Från görande till lärande och förståelse; En studie av lärares lärande inom estetik

Directory of Open Access Journals (Sweden)

Maj Asplund Carlsson

2008-10-01

Full Text Available

The aim of this article is to analyse teachers’ changing ways of talking about children’s aesthetic learn-Helvetica;"> 

ing in the early years as a result of a research and development project. With a point of departure in developmen-Helvetica;"> 

tal and variation theory, a praxis oriented project was designed with the aim of finding out whether collaborative 

talk and meta-cognitive dialogues could contribute to children’s learning of music, dance and poetry. The partici-Helvetica;"> 

pating teachers were offered in-service training in order to develop a new way of teaching and new ways of think-Helvetica;"> 

ing about the curriculum and children’s learning. Interviews with the teachers were carried out at the beginning 

and the end of the project. The teachers’ learning was expressed in changed ways of talking about aesthetics and 

learning. From an emphasis on personality development and the teacher’s lack of expertise with the aesthetic sub-Helvetica;"> 

jects as an obstacle, the teachers expressed a view of having become more aware of the concept of learning objects 

in the aesthetics, of their own role as teachers in directing

Dew point vs bubble point : a misunderstood constraint on gravity drainage processes

Energy Technology Data Exchange (ETDEWEB)

Nenninger, J. [N-Solv Corp., Calgary, AB (Canada); Gunnewiek, L. [Hatch Ltd., Mississauga, ON (Canada)

2009-07-01

This study demonstrated that gravity drainage processes that use blended fluids such as solvents have an inherently unstable material balance due to differences between dew point and bubble point compositions. The instability can lead to the accumulation of volatile components within the chamber, and impair mass and heat transfer processes. Case studies were used to demonstrate the large temperature gradients within the vapour chamber caused by temperature differences between the bubble point and dew point for blended fluids. A review of published data showed that many experiments on in-situ processes do not account for unstable material balances caused by a lack of steam trap control. A study of temperature profiles during steam assisted gravity drainage (SAGD) studies showed significant temperature depressions caused by methane accumulations at the outside perimeter of the steam chamber. It was demonstrated that the condensation of large volumes of purified solvents provided an efficient mechanism for the removal of methane from the chamber. It was concluded that gravity drainage processes can be optimized by using pure propane during the injection process. 22 refs., 1 tab., 18 figs.

Cerebral Asymmetry of fMRI-BOLD Responses to Visual Stimulation.

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Anders Hougaard

Full Text Available Hemispheric asymmetry of a wide range of functions is a hallmark of the human brain. The visual system has traditionally been thought of as symmetrically distributed in the brain, but a growing body of evidence has challenged this view. Some highly specific visual tasks have been shown to depend on hemispheric specialization. However, the possible lateralization of cerebral responses to a simple checkerboard visual stimulation has not been a focus of previous studies. To investigate this, we performed two sessions of blood-oxygenation level dependent (BOLD functional magnetic resonance imaging (fMRI in 54 healthy subjects during stimulation with a black and white checkerboard visual stimulus. While carefully excluding possible non-physiological causes of left-to-right bias, we compared the activation of the left and the right cerebral hemispheres and related this to grey matter volume, handedness, age, gender, ocular dominance, interocular difference in visual acuity, as well as line-bisection performance. We found a general lateralization of cerebral activation towards the right hemisphere of early visual cortical areas and areas of higher-level visual processing, involved in visuospatial attention, especially in top-down (i.e., goal-oriented attentional processing. This right hemisphere lateralization was partly, but not completely, explained by an increased grey matter volume in the right hemisphere of the early visual areas. Difference in activation of the superior parietal lobule was correlated with subject age, suggesting a shift towards the left hemisphere with increasing age. Our findings suggest a right-hemispheric dominance of these areas, which could lend support to the generally observed leftward visual attentional bias and to the left hemifield advantage for some visual perception tasks.

NUTRIÇÃO E PRODUÇÃO DE MATÉRIA SECA DE MILHO SUBMETIDO A CALAGEM E ADUBAÇÃO SULFATADA MAIZE NUTRITION AND DRY MATTER YIELD UNDER LIMING AND SULFUR FERTILIZATION

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Aretusa Daniela Resende Mendes

2011-04-01

Full Text Available

Helvetica, sans-serif;">A calagem é uma prática indispensável para obtenção de altos rendimentos das culturas, em solos tropicais ácidos. Objetivou-se avaliar a nutrição e produção de matéria seca de milho, em solo submetido a calagem estimada por três métodos de cálculo e adubação sulfatada. O experimento foi desenvolvido em casa-de-vegetação, em tubos de PVC, com uma planta por tubo. Utilizou-se Latossolo Vermelho distrófico (LVd, sob vegetação nativa. Foi aplicado calcário dolomítico, tipo filler, nas doses de 4,2 Mg ha^{Helvetica, sans-serif;">-1}Helvetica, sans-serif;">; 6,7 Mg ha^{Helvetica, sans-serif;">-1}Helvetica, sans-serif;">; e 8,0 Mg ha^{Helvetica, sans-serif;">-1}Helvetica, sans-serif;">, calculadas pelo método do alumínio trocável, cálcio e magnésio; método da elevação da saturação por bases; e método do tampão SMP, respectivamente, além do tratamento sem aplicação de calcário, combinados com três doses de S (10 mg dm

Functional evaluation of transplanted kidneys in normal function and acute rejection using BOLD MR imaging

International Nuclear Information System (INIS)

Xiao Wenbo; Xu Jingjing; Wang Qindong; Xu Ying; Zhang Minming

2012-01-01

In this study, we evaluated a large number of subjects using BOLD MRI to provide more information about oxygen metabolism in the normal function of transplanted kidneys and to distinguish acute graft rejection from normal function kidneys. This study included 122 subjects (20 volunteers, 72 patients with normal functioning transplants, and 21 patients with acute rejection), and 9 patients had normal function grafts received examination while grafts dysfunction occurred within 6 months during the follow-up. The R2* (1/s) values in the cortex and medulla as well as the R2* ratio of the medulla to cortex (R2* ratio of M/C) were recorded. The R2* values of the medulla were higher than those of the cortex in the normal function group and the volunteers which have a steep R2* ratio of M/C. All the R2* values in the acute rejection group were lower than those in the normal function grafts group (P 1.1) is an important reason for keeping clinical normal function.

18{beta}-Glycyrrhetinic acid inhibits adipogenic differentiation and stimulates lipolysis

Energy Technology Data Exchange (ETDEWEB)

Moon, Myung-Hee; Jeong, Jae-Kyo; Lee, You-Jin; Seol, Jae-Won; Ahn, Dong-Choon; Kim, In-Shik [Center for Healthcare Technology Development, Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Park, Sang-Youel, E-mail: sypark@chonbuk.ac.kr [Center for Healthcare Technology Development, Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

2012-04-20

Highlights: Black-Right-Pointing-Pointer 18{beta}-GA inhibits adipogenic differentiation in 3T3-L1 preadipocytes and stimulates lipolysis in differentiated adipocytes. Black-Right-Pointing-Pointer Anti-adipogenic effect of 18{beta}-GA is caused by down-regulation of PPAR{gamma} and inactivation of Akt signalling. Black-Right-Pointing-Pointer Lipolytic effect of 18{beta}-GA is mediated by up-regulation of HSL, ATGL and perilipin and activation of HSL. -- Abstract: 18{beta}-Glycyrrhetinic acid (18{beta}-GA) obtained from the herb liquorice has various pharmacological properties including anti-inflammatory and anti-bacterial activities. However, potential biological anti-obesity activities are unclear. In this study, novel biological activities of 18{beta}-GA in the adipogenesis of 3T3-L1 preadipocytes and in lipolysis of differentiated adipocytes were identified. Mouse 3T3-L1 cells were used as an in vitro model of adipogenesis and lipolysis, using a mixture of insulin/dexamethasone/3-isobutyl-1-methylxanthine (IBMX) to induce differentiation. The amount of lipid droplet accumulation was determined by an AdipoRed assay. The expression of several adipogenic transcription factors and enzymes was investigated using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. 18{beta}-GA dose-dependently (1-40 {mu}M) significantly decreased lipid accumulation in maturing preadipocytes. In 3T3-L1 preadipocytes, 10 {mu}M of 18{beta}-GA down-regulated the transcriptional levels of the peroxisome proliferator-activated receptor {gamma}, CCAAT/enhancer-binding protein {alpha} and adiponectin, which are markers of adipogenic differentiation via Akt phosphorylation. Also, in differentiated adipocytes, 18{beta}-GA increased the level of glycerol release and up-regulated the mRNA of hormone-sensitive lipase, adipose TG lipase and perilipin, as well as the phosphorylation of hormone-sensitive lipase at Serine 563. The results indicate that 18{beta

Ratio of dopamine synthesis capacity to D2 receptor availability in ventral striatum correlates with central processing of affective stimuli

Energy Technology Data Exchange (ETDEWEB)

Kienast, Thorsten; Rapp, Michael [Charite Campus Mitte, Department of Psychiatry and Psychotherapy of the Charite University Medical Center, Berlin (Germany); Siessmeier, Thomas; Buchholz, Hans G.; Schreckenberger, Mathias [University of Mainz, Department of Nuclear Medicine, Mainz (Germany); Wrase, Jana; Heinz, Andreas [Charite Campus Mitte, Department of Psychiatry and Psychotherapy of the Charite University Medical Center, Berlin (Germany); Central Institute of Mental Health, Mannheim (Germany); Braus, Dieter F. [University of Hamburg, Neuroimage Nord, Department of Psychiatry, Hamburg (Germany); Smolka, Michael N.; Mann, Karl [Central Institute of Mental Health, Mannheim (Germany); Roesch, Frank [University of Mainz, Institute of Nuclear Chemistry, Mainz (Germany); Cumming, Paul [PET Center and Center for Functionally Integrative Neuroscience, Aarhus (Denmark); Gruender, Gerhard [Aachen University Medical Center, Department of Psychiatry of the RWTH, Mainz (Germany); Bartenstein, Peter [Ludwig-Maximilians-University, Department of Nuclear Medicine, Munich (Germany)

2008-06-15

Dopaminergic neurotransmission in the ventral striatum may interact with limbic processing of affective stimuli, whereas dorsal striatal dopaminergic neurotransmission can affect habitual processing of emotionally salient stimuli in the pre-frontal cortex. We investigated the dopaminergic neurotransmission in the ventral and dorsal striatum with respect to central processing of affective stimuli in healthy subjects. Subjects were investigated with positron emission tomography and [{sup 18}F]DOPA for measurements of dopamine synthesis capacity and [{sup 18}F]DMFP for estimation of dopamine D2 receptor binding potential. Functional magnetic resonance imaging was used to assess the blood-oxygen-level-dependent (BOLD) response to affective pictures, which was correlated with the ratio of [{sup 18}F]DOPA net influx constant K{sub in}{sup app} /[{sup 18}F]DMFP-binding potential (BP{sub N}D) in the ventral and dorsal striatum. The magnitude of the ratio in the ventral striatum was positively correlated with BOLD signal increases elicited by negative versus neutral pictures in the right medial frontal gyrus (BA10), right inferior parietal lobe and left post-central gyrus. In the dorsal striatum, the ratio was positively correlated with BOLD signal activation elicited by negative versus neutral stimuli in the left post-central gyrus. The BOLD signal elicited by positive versus neutral stimuli in the superior parietal gyrus was positively correlated with the dorsal and ventral striatal ratio. The correlations of the ratio in the ventral and dorsal striatum with processing of affective stimuli in the named cortical regions support the hypothesis that dopamine transmission in functional divisions of the striatum modulates processing of affective stimuli in specific cortical areas. (orig.)

High spatial correspondence at a columnar level between activation and resting state fMRI signals and local field potentials.

Science.gov (United States)

Shi, Zhaoyue; Wu, Ruiqi; Yang, Pai-Feng; Wang, Feng; Wu, Tung-Lin; Mishra, Arabinda; Chen, Li Min; Gore, John C

2017-05-16

Although blood oxygenation level-dependent (BOLD) fMRI has been widely used to map brain responses to external stimuli and to delineate functional circuits at rest, the extent to which BOLD signals correlate spatially with underlying neuronal activity, the spatial relationships between stimulus-evoked BOLD activations and local correlations of BOLD signals in a resting state, and whether these spatial relationships vary across functionally distinct cortical areas are not known. To address these critical questions, we directly compared the spatial extents of stimulated activations and the local profiles of intervoxel resting state correlations for both high-resolution BOLD at 9.4 T and local field potentials (LFPs), using 98-channel microelectrode arrays, in functionally distinct primary somatosensory areas 3b and 1 in nonhuman primates. Anatomic images of LFP and BOLD were coregistered within 0.10 mm accuracy. We found that the point spread functions (PSFs) of BOLD and LFP responses were comparable in the stimulus condition, and both estimates of activations were slightly more spatially constrained than local correlations at rest. The magnitudes of stimulus responses in area 3b were stronger than those in area 1 and extended in a medial to lateral direction. In addition, the reproducibility and stability of stimulus-evoked activation locations within and across both modalities were robust. Our work suggests that the intrinsic resolution of BOLD is not a limiting feature in practice and approaches the intrinsic precision achievable by multielectrode electrophysiology.

The late endosome/lysosome-anchored p18-mTORC1 pathway controls terminal maturation of lysosomes

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Yusuke; Nada, Shigeyuki; Mori, Shunsuke; Soma-Nagae, Taeko; Oneyama, Chitose [Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Okada, Masato, E-mail: okadam@biken.osaka-u.ac.jp [Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2012-01-27

Highlights: Black-Right-Pointing-Pointer p18 is a membrane adaptor that anchors mTORC1 to late endosomes/lysosomes. Black-Right-Pointing-Pointer We examine the role of the p18-mTORC1 pathway in lysosome biogenesis. Black-Right-Pointing-Pointer The loss of p18 causes accumulation of intact late endosomes by arresting lysosome maturation. Black-Right-Pointing-Pointer Inhibition of mTORC1 activity with rapamycin phenocopies the defects of p18 loss. Black-Right-Pointing-Pointer The p18-mTORC1 pathway plays crucial roles in the terminal maturation of lysosomes. -- Abstract: The late endosome/lysosome membrane adaptor p18 (or LAMTOR1) serves as an anchor for the mammalian target of rapamycin complex 1 (mTORC1) and is required for its activation on lysosomes. The loss of p18 causes severe defects in cell growth as well as endosome dynamics, including membrane protein transport and lysosome biogenesis. However, the mechanisms underlying these effects on lysosome biogenesis remain unknown. Here, we show that the p18-mTORC1 pathway is crucial for terminal maturation of lysosomes. The loss of p18 causes aberrant intracellular distribution and abnormal sizes of late endosomes/lysosomes and an accumulation of late endosome specific components, including Rab7, RagC, and LAMP1; this suggests that intact late endosomes accumulate in the absence of p18. These defects are phenocopied by inhibiting mTORC1 activity with rapamycin. Loss of p18 also suppresses the integration of late endosomes and lysosomes, resulting in the defective degradation of tracer proteins. These results suggest that the p18-mTORC1 pathway plays crucial roles in the late stages of lysosomal maturation, potentially in late endosome-lysosome fusion, which is required for processing of various macromolecules.

40 CFR 469.18 - Pretreatment standards for new sources (PSNS).

Science.gov (United States)

2010-07-01

... (PSNS). 469.18 Section 469.18 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ELECTRICAL AND ELECTRONIC COMPONENTS POINT SOURCE CATEGORY Semiconductor... monitoring pursuant to § 469.13 (c) and (d) of this regulation must implement the solvent management plan...

SLAG, LIMESTONE, AND UREA APPLICATION IN LATOSOL CULTIVATED WITH RICE APLICAÇÃO DE ESCÓRIA SIDERÚRGICA, CALCÁRIO E UREIA EM LATOSSOLO CULTIVADO COM ARROZ

Directory of Open Access Journals (Sweden)

Renato de Mello Prado

2011-04-01

Full Text Available Slag is a calcium silicate and silicon source, whose corrective action on soil is similar to the limestone one. Despite its corrective and fertilizing potential, there is little information about its effects on soil chemical attributes. The study evaluated the effects of the slag, limestone, and urea application on the chemical attributes of a Brazilian Oxisol cultivated with rice. The treatments consisted of two corrective agents sources (limestone and slag, with three doses (1.3 g dm-3, 2.6 g dm-3, and 5,2 g dm-3; three N doses (80 mg dm-3, 160 mg dm-3, and 320 mg dm-3, applied as urea; and a control, arranged in randomized blocks, in a factorial scheme, with four replications. Ninety days after the soil incubation and 120 days after planting, soil samples were collected for chemical analysis. The slag was efficient in correcting soil acidity, and nitrogen fertilization contributed to increment acidity in the soil cultivated with rice, decreasing base saturation, as well as the Ca and Mg content. The slag application improved silicon availability, however, when associate to the nitrogen fertilization, the silicon content in the soil did not change.

Helvetica, sans-serif;">A escória de siderurgia é um silicato de cálcio e fonte de silício, que tem ação corretiva da acidez do solo semelhante à do calcário. Apesar do seu grande potencial de uso como corretivo e fertilizante, existem poucas informações sobre seus efeitos nos atributos químicos do solo. O estudo foi realizado com a cultura do arroz, objetivando-se avaliar os efeitos da aplicação da escória de siderurgia, calcário e ureia nas alterações dos atributos químicos de um Latossolo Vermelho distrófico. Os tratamentos constaram da combinação de duas fontes de materiais corretivos (calcário e esc

Correlation between levels of human papillomavirus (HPV)-16 and 18 antibodies in serum and cervicovaginal secretions in girls and women vaccinated with the HPV-16/18 AS04-adjuvanted vaccine

DEFF Research Database (Denmark)

Schwarz, Tino F; Kocken, Mariëlle; Petäjä, Tiina

2010-01-01

and CVS samples were collected from a subset of women aged 10-65 years (N=350) at pre-specified time-points from 7 to 36 months post-vaccination. Anti-HPV-16/18 antibody levels in serum and CVS were measured by enzyme-linked immunosorbent assay. Pearson correlation coefficients between serum and CVS...... in serum were substantially higher at all time-points than those in a control group of women who had cleared a natural HPV infection in another trial. In women with detectable antibodies in both serum and CVS, good correlation was seen between HPV-16/18 antibody levels at all time-points (Pearson......This pooled analysis of data from four Phase III clinical trials was undertaken to assess the correlation between levels of anti-human papillomavirus (HPV)-16/18 antibodies in serum and cervicovaginal secretions (CVS) in girls and women vaccinated with the HPV-16/18 AS04-adjuvanted vaccine. Serum...

Brain activation by short-term nicotine exposure in anesthetized wild-type and beta2-nicotinic receptors knockout mice: a BOLD fMRI study

Energy Technology Data Exchange (ETDEWEB)

Suarez, S.V.; Changeux, J.P.; Granon, S. [Unite de Neurobiologie Integrative du Systeme Cholinergique, URA CNRS 2182, Institut Pasteur, Departement de Neuroscience, 25 rue du Dr Roux, 75015 Paris (France); Amadon, A.; Giacomini, E.; Le Bihan, D. [Service Hospitalier Frederic Joliot, 4 place du general Leclerc, 91400 Orsay (France); Wiklund, A. [Section of Anaesthesiology and Intensive Care Medicine, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm (Sweden)

2009-07-01

Rationale: The behavioral effects of nicotine and the role of the beta2-containing nicotinic receptors in these behaviors are well documented. However, the behaviors altered by nicotine rely on the functioning on multiple brain circuits where the high-affinity {beta}2-containing nicotinic receptors ({beta}2*nAChRs) are located. Objectives We intend to see which brain circuits are activated when nicotine is given in animals naive for nicotine and whether the {beta}2*nAChRs are needed for its activation of the blood oxygen level dependent (BOLD) signal in all brain areas. Materials and methods: We used functional magnetic resonance imaging (fMRI) to measure the brain activation evoked by nicotine (1 mg/kg delivered at a slow rate for 45 min) in anesthetized C57BL/6J mice and {beta}2 knockout (KO) mice. Results: Acute nicotine injection results in a significant increased activation in anterior frontal, motor, and somatosensory cortices and in the ventral tegmental area and the substantia nigra. Anesthetized mice receiving no nicotine injection exhibited a major decreased activation in all cortical and subcortical structures, likely due to prolonged anesthesia. At a global level, {beta}2 KO mice were not rescued from the globally declining BOLD signal. However, nicotine still activated regions of a meso-cortico-limbic circuit likely via {alpha}7 nicotinic receptors. Conclusions: Acute nicotine exposure compensates for the drop in brain activation due to anesthesia through the meso-cortico-limbic network via the action of nicotine on {beta}2*nAChRs. The developed fMRI method is suitable for comparing responses in wild-type and mutant mice. (authors)

Brain activation by short-term nicotine exposure in anesthetized wild-type and beta2-nicotinic receptors knockout mice: a BOLD fMRI study

International Nuclear Information System (INIS)

Suarez, S.V.; Changeux, J.P.; Granon, S.; Amadon, A.; Giacomini, E.; Le Bihan, D.; Wiklund, A.

2009-01-01

Rationale: The behavioral effects of nicotine and the role of the beta2-containing nicotinic receptors in these behaviors are well documented. However, the behaviors altered by nicotine rely on the functioning on multiple brain circuits where the high-affinity β2-containing nicotinic receptors (β2*nAChRs) are located. Objectives We intend to see which brain circuits are activated when nicotine is given in animals naive for nicotine and whether the β2*nAChRs are needed for its activation of the blood oxygen level dependent (BOLD) signal in all brain areas. Materials and methods: We used functional magnetic resonance imaging (fMRI) to measure the brain activation evoked by nicotine (1 mg/kg delivered at a slow rate for 45 min) in anesthetized C57BL/6J mice and β2 knockout (KO) mice. Results: Acute nicotine injection results in a significant increased activation in anterior frontal, motor, and somatosensory cortices and in the ventral tegmental area and the substantia nigra. Anesthetized mice receiving no nicotine injection exhibited a major decreased activation in all cortical and subcortical structures, likely due to prolonged anesthesia. At a global level, β2 KO mice were not rescued from the globally declining BOLD signal. However, nicotine still activated regions of a meso-cortico-limbic circuit likely via α7 nicotinic receptors. Conclusions: Acute nicotine exposure compensates for the drop in brain activation due to anesthesia through the meso-cortico-limbic network via the action of nicotine on β2*nAChRs. The developed fMRI method is suitable for comparing responses in wild-type and mutant mice. (authors)

Indirect determination of the thermodynamic temperature of the copper point by a multi-fixed-point technique

Science.gov (United States)

Battuello, M.; Florio, M.; Girard, F.

2010-06-01

An indirect determination of the thermodynamic temperature of the fixed point of copper was made at INRIM by measuring four cells with a Si-based and an InGaAs-based precision radiation thermometer carrying approximated thermodynamic scales realized up to the Ag point. An average value TCu = 1357.840 K was found with a standard uncertainty of 0.047 K. A consequent (T - T90)Cu value of 70 mK can be derived which is 18 mK higher than, but consistent with, the presently available (T - T90)Cu as elaborated by the CCT-WG4.

17 CFR 240.14d-102 - Schedule 14D-1F. Tender offer statement pursuant to rule 14d-1(b) under the Securities Exchange...

Science.gov (United States)

2010-04-01

... satisfy the legibility requirements for the required legends relating to type size and font by presenting... bold-face roman type at least as high as ten-point modern type and at least two points leaded: “This...

Radiosynthesis of 1-[{sup 18}F]fluoroethyl-L-tryptophan as a novel potential amino acid PET tracer

Energy Technology Data Exchange (ETDEWEB)

Sun Ting, E-mail: beibeisun2008@163.com [Department of Cardiac Function, Shanghai Ninth People' s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Tang Ganghua, E-mail: gtang0224@yahoo.com.cn [Department of Nuclear Medicine, the first affiliated hospital, SunYat-Sen University, Guangzhou 510080 (China); Tian Hua [State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200032 (China); Wang Xiaoyan [Department of Nuclear Medicine, the first affiliated hospital, SunYat-Sen University, Guangzhou 510080 (China); Chen Xianghua [Department of Cardiac Function, Shanghai Ninth People' s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Chen Zhifeng [Department of Nuclear Medicine, the first affiliated hospital, SunYat-Sen University, Guangzhou 510080 (China); Wang Shihchen [Department of Nuclear Medicine, Peking Union Medical College and Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, 1 Shuaifuyuan Wangfujing Beijing 100730 (China)

2012-04-15

{sup 18}F labeled natural amino acids have been introduced as promising tumor imaging agents. A novel [{sup 18}F]fluoro amino acid analog 1-[{sup 18}F]fluoroethyl-L-tryptophan (1-[{sup 18}F]FETrp) was designed and synthesized by a two-pot three-step procedure, including the synthesis of 1-[{sup 18}F]fluoro-2- (tosyloxy)ethane, the [{sup 18}F]fluoroethylation of the precursor N-Boc-L-tryptophan ethyl ester and following the deprotection of the tert-butoxycarbonyl and ethyl ester protecting groups. 1-[{sup 18}F]FETrp was resulted in 0.9{+-}0.2% (n=5) radiochemical yields (no decay corrected) by HPLC purification, within a total synthesis time of 65 min. The radiochemical purity of 1-[{sup 18}F]FETrp was 95-97%. The radiosynthetic method needs to be further optimized to get a satisfying radiochemical yield. - Highlights: Black-Right-Pointing-Pointer We designed and synthesized the novel amino acid analog 1-[{sup 19}F]FETrp. Black-Right-Pointing-Pointer We radiosynthesized 1-[{sup 18}F]FETrp using the two-pot three-step procedure. Black-Right-Pointing-Pointer The total synthesis time was 65 min and the yield was very low. Black-Right-Pointing-Pointer The synthetic strategy via [{sup 18}F]FCH{sub 2}CH{sub 2}OTs needs to be optimized or changed.

N ecklaces~ Periodic Points and Permutation Representations

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 11. Necklaces, Periodic Points and Permutation Representations - Fermat's Little Theorem. Somnath Basu Anindita Bose Sumit Kumar Sinha Pankaj Vishe. General Article Volume 6 Issue 11 November 2001 pp 18-26 ...

Averroes' Physics A Turning Point in Medieval Natural Philosophy

CERN Document Server

Glasner, Ruth

2009-01-01

Ruth Glasner presents an illuminating reappraisal of Averroes' physics. Glasner is the first scholar to base her interpretation on the full range of Averroes' writings, including texts that are extant only in Hebrew manuscripts and have not been hitherto studied. She reveals that Averroes changed his interpretation of the basic notions of physics - the structure of corporeal reality and the definition of motion - more than once. After many hesitations he offers a bold newinterpretation of physics which Glasner calls 'Aristotelian atomism'. Ideas that are usually ascribed to scholastic scholars

WHO Better Outcomes in Labour Difficulty (BOLD) project: innovating to improve quality of care around the time of childbirth.

Science.gov (United States)

Oladapo, Olufemi T; Souza, João Paulo; Bohren, Meghan A; Tunçalp, Özge; Vogel, Joshua P; Fawole, Bukola; Mugerwa, Kidza; Gülmezoglu, A Metin

2015-05-26

As most pregnancy-related deaths and morbidities are clustered around the time of childbirth, quality of care during this period is critical to the survival of pregnant women and their babies. Despite the wide acceptance of partograph as the central tool to optimize labour outcomes for over 40 years, its use has not successfully improved outcomes in many settings for several reasons. There are also increasing questions about the validity and applicability of its central feature - "the alert line" - to all women regardless of their labour characteristics. Apart from the known deficiencies in labour care, attempts to improve quality of care in low resource settings have also failed to address and integrate women's birth experience into quality improvement processes. It was against this background that the World Health Organization (WHO) embarked on the Better Outcomes in Labour Difficulty (BOLD) project to improve the quality of intrapartum care in low- and middle-income countries. The main goal of the BOLD project is to reduce intrapartum-related stillbirths, maternal and newborn mortalities and morbidities by addressing the critical barriers to the process of good quality intrapartum care and enhancing the connection between health systems and communities. The project seeks to achieve this goal by (1) developing an evidence-based, easy to use, labour monitoring-to-action decision-support tool (currently termed Simplified, Effective, Labour Monitoring-to-Action - SELMA); and (2) by developing innovative service prototypes/tools, co-designed with users of health services (women, their families and communities) and health providers, to promote access to respectful, dignified and emotionally supportive care for pregnant women and their companions at the time of birth ("Passport to Safer Birth"). This two-pronged approach is expected to positively impact on important domains of quality of care relating to both provision and experience of care. In this paper, we briefly

49 CFR 375.213 - What information must I provide to a prospective individual shipper?

Science.gov (United States)

2010-10-01

... type font size is 10 points or larger and the size of the booklet is at least as large as 36 square... cover in 12-point or larger bold or full-faced type: “Your Rights and Responsibilities When You Move...

18 CFR 801.11 - Public values.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Public values. 801.11... POLICIES § 801.11 Public values. (a) The basin has many points of archeological and historic interest, and... value of these areas cannot be measured simply in economic terms and will strive to preserve and promote...

76 FR 12278 - Amendment to and Revocation of Reporting Points; Hawaii

Science.gov (United States)

2011-03-07

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA-2011-0018; Airspace Docket No. 10-AWP-18] Amendment to and Revocation of Reporting Points; Hawaii AGENCY... scope of that authority as it amends Reporting Points in Hawaii. Environmental Review The FAA has...

Internal representations for face detection: an application of noise-based image classification to BOLD responses.

Science.gov (United States)

Nestor, Adrian; Vettel, Jean M; Tarr, Michael J

2013-11-01

What basic visual structures underlie human face detection and how can we extract such structures directly from the amplitude of neural responses elicited by face processing? Here, we address these issues by investigating an extension of noise-based image classification to BOLD responses recorded in high-level visual areas. First, we assess the applicability of this classification method to such data and, second, we explore its results in connection with the neural processing of faces. To this end, we construct luminance templates from white noise fields based on the response of face-selective areas in the human ventral cortex. Using behaviorally and neurally-derived classification images, our results reveal a family of simple but robust image structures subserving face representation and detection. Thus, we confirm the role played by classical face selective regions in face detection and we help clarify the representational basis of this perceptual function. From a theory standpoint, our findings support the idea of simple but highly diagnostic neurally-coded features for face detection. At the same time, from a methodological perspective, our work demonstrates the ability of noise-based image classification in conjunction with fMRI to help uncover the structure of high-level perceptual representations. Copyright © 2012 Wiley Periodicals, Inc.

Quantitative comparisons on hand motor functional areas determined by resting state and task BOLD fMRI and anatomical MRI for pre-surgical planning of patients with brain tumors

Directory of Open Access Journals (Sweden)

Bob L. Hou

2016-01-01

Full Text Available For pre-surgical planning we present quantitative comparison of the location of the hand motor functional area determined by right hand finger tapping BOLD fMRI, resting state BOLD fMRI, and anatomically using high resolution T1 weighted images. Data were obtained on 10 healthy subjects and 25 patients with left sided brain tumors. Our results show that there are important differences in the locations (i.e., >20 mm of the determined hand motor voxels by these three MR imaging methods. This can have significant effect on the pre-surgical planning of these patients depending on the modality used. In 13 of the 25 cases (i.e., 52% the distances between the task-determined and the rs-fMRI determined hand areas were more than 20 mm; in 13 of 25 cases (i.e., 52% the distances between the task-determined and anatomically determined hand areas were >20 mm; and in 16 of 25 cases (i.e., 64% the distances between the rs-fMRI determined and anatomically determined hand areas were more than 20 mm. In just three cases, the distances determined by all three modalities were within 20 mm of each other. The differences in the location or fingerprint of the hand motor areas, as determined by these three MR methods result from the different underlying mechanisms of these three modalities and possibly the effects of tumors on these modalities.

Linear increases in BOLD response associated with increasing proportion of incongruent trials across time in a colour Stroop task.

Science.gov (United States)

Mitchell, Rachel L C

2010-05-01

Selective attention is popularly assessed with colour Stroop tasks in which participants name the ink colour of colour words, whilst resisting interference from the natural tendency to read the words. Prior studies hinted that the key brain regions (dorsolateral prefrontal (dlPFC) and anterior cingulate cortex (ACC)) may vary their degree of involvement, dependent on attentional demand. This study aimed to determine whether a parametrically varied increase in attentional demand resulted in linearly increased activity in these regions, and/or whether additional regions would be recruited during high attentional demand. Twenty-eight healthy young adults underwent fMRI whilst naming the font colour of colour words. Linear increases in BOLD response were assessed with increasing percentage incongruent trials per block (0, 20, 40, 60, 80, and 100%). Whilst ACC activation increased linearly according to incongruity level, dlPFC activity appeared constant. Together with behavioural evidence of reduced Stroop interference, these data support a load-dependent conflict-related response in ACC, but not dlPFC.

The Anti-Inflammatory properties of interleukin 18 binding protein in ...

African Journals Online (AJOL)

This study pointed out that IL-18BPa has additional anti-inflammatory property through downregulating the expression of IFN-ã and IL-12, at the same time, upregulating the expression of IL-4 and IL-10. Both IFN-ã and IL-12 could upregulated the mRNA and protein levels of IL-18BPa in both the normal and RA subjects.

Bright point study

International Nuclear Information System (INIS)

Tang, F.; Harvey, K.; Bruner, M.; Kent, B.; Antonucci, E.

1982-01-01

Transition region and coronal observations of bright points by instruments aboard the Solar Maximum Mission and high resolution photospheric magnetograph observations on September 11, 1980 are presented. A total of 31 bipolar ephemeral regions were found in the photosphere from birth in 9.3 hours of combined magnetograph observations from three observatories. Two of the three ephemeral regions present in the field of view of the Ultraviolet Spectrometer-Polarimeter were observed in the C IV 1548 line. The unobserved ephemeral region was determined to be the shortest-lived (2.5 hr) and lowest in magnetic flux density (13G) of the three regions. The Flat Crystal Spectrometer observed only low level signals in the O VIII 18.969 A line, which were not statistically significant to be positively identified with any of the 16 ephemeral regions detected in the photosphere. In addition, the data indicate that at any given time there lacked a one-to-one correspondence between observable bright points and photospheric ephemeral regions, while more ephemeral regions were observed than their counterparts in the transition region and the corona

Music reduces pain and increases resting state fMRI BOLD signal amplitude in the left angular gyrus in fibromyalgia patients

DEFF Research Database (Denmark)

Garza-Villarreal, Eduardo A; Jiang, Zhiguo; Vuust, Peter

2015-01-01

, correlated to the analgesia reports. The post-hoc seed-based functional connectivity analysis of the lAnG showed found higher connectivity after listening to music with right dorsolateral prefrontal cortex (rdlPFC), the left caudate (lCau), and decreased connectivity with right anterior cingulate cortex (r......Music reduces pain in fibromyalgia (FM), a chronic pain disease, but the functional neural correlates of music-induced analgesia (MIA) are still largely unknown. We recruited FM patients (n = 22) who listened to their preferred relaxing music and an auditory control (pink noise) for 5 min without...... external noise from fMRI image acquisition. Resting state fMRI was then acquired before and after the music and control conditions. A significant increase in the amplitude of low frequency fluctuations of the BOLD signal was evident in the left angular gyrus (lAnG) after listening to music, which in turn...

Graph Theoretical Analysis of BOLD Functional Connectivity during Human Sleep without EEG Monitoring.

Directory of Open Access Journals (Sweden)

Jun Lv

Full Text Available Functional brain networks of human have been revealed to have small-world properties by both analyzing electroencephalogram (EEG and functional magnetic resonance imaging (fMRI time series.In our study, by using graph theoretical analysis, we attempted to investigate the changes of paralimbic-limbic cortex between wake and sleep states. Ten healthy young people were recruited to our experiment. Data from 2 subjects were excluded for the reason that they had not fallen asleep during the experiment. For each subject, blood oxygen level dependency (BOLD images were acquired to analyze brain network, and peripheral pulse signals were obtained continuously to identify if the subject was in sleep periods. Results of fMRI showed that brain networks exhibited stronger small-world characteristics during sleep state as compared to wake state, which was in consistent with previous studies using EEG synchronization. Moreover, we observed that compared with wake state, paralimbic-limbic cortex had less connectivity with neocortical system and centrencephalic structure in sleep.In conclusion, this is the first study, to our knowledge, has observed that small-world properties of brain functional networks altered when human sleeps without EEG synchronization. Moreover, we speculate that paralimbic-limbic cortex organization owns an efficient defense mechanism responsible for suppressing the external environment interference when humans sleep, which is consistent with the hypothesis that the paralimbic-limbic cortex may be functionally disconnected from brain regions which directly mediate their interactions with the external environment. Our findings also provide a reasonable explanation why stable sleep exhibits homeostasis which is far less susceptible to outside world.

Holographic Location of Distant Points (PREPRINT)

Science.gov (United States)

2010-06-01

respects and the nonimaging systems have significant advantages. This paper shows how to use holograms to construct a flat, solid, small, accurate, small... nonimaging point location system. 15. SUBJECT TERMS imagery, holographic 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT: SAR 18...respects and the nonimaging systems we have discussed earlier (1, 2) have significant advantages. This paper shows how to use holograms to construct a

OH masers associated with IRAS point sources

NARCIS (Netherlands)

Masheder, MRW; Cohen, RJ; Martin-Hernandez, NL; Migenes,; Reid, MJ

2002-01-01

We report a search for masers from the Lambda-doublet of the ground-state of OH at 18cm, carried out with the Jodrell Bank Lovell Telescope and with the 25m Dwingeloo telescope. All objects north of delta = -20degrees which appear in the IRAS Point Source Catalog with fluxes > 1000 Jy at 60mum and

Common brain regions underlying different arithmetic operations as revealed by conjunct fMRI-BOLD activation.

Science.gov (United States)

Fehr, Thorsten; Code, Chris; Herrmann, Manfred

2007-10-03

The issue of how and where arithmetic operations are represented in the brain has been addressed in numerous studies. Lesion studies suggest that a network of different brain areas are involved in mental calculation. Neuroimaging studies have reported inferior parietal and lateral frontal activations during mental arithmetic using tasks of different complexities and using different operators (addition, subtraction, etc.). Indeed, it has been difficult to compare brain activation across studies because of the variety of different operators and different presentation modalities used. The present experiment examined fMRI-BOLD activity in participants during calculation tasks entailing different arithmetic operations -- addition, subtraction, multiplication and division -- of different complexities. Functional imaging data revealed a common activation pattern comprising right precuneus, left and right middle and superior frontal regions during all arithmetic operations. All other regional activations were operation specific and distributed in prominently frontal, parietal and central regions when contrasting complex and simple calculation tasks. The present results largely confirm former studies suggesting that activation patterns due to mental arithmetic appear to reflect a basic anatomical substrate of working memory, numerical knowledge and processing based on finger counting, and derived from a network originally related to finger movement. We emphasize that in mental arithmetic research different arithmetic operations should always be examined and discussed independently of each other in order to avoid invalid generalizations on arithmetics and involved brain areas.

The association between chronic airflow obstruction and poverty in 12 sites of the multinational BOLD study.

Science.gov (United States)

Townend, John; Minelli, Cosetta; Mortimer, Kevin; Obaseki, Daniel O; Al Ghobain, Mohammed; Cherkaski, Hamid; Denguezli, Myriam; Gunesekera, Kirthi; Hafizi, Hasan; Koul, Parvaiz A; Loh, Li C; Nejjari, Chakib; Patel, Jaymini; Sooronbayev, Talant; Buist, Sonia A; Burney, Peter G J

2017-06-01

Poverty is strongly associated with mortality from COPD, but little is known of its relation to airflow obstruction.In a cross-sectional study of adults aged ≥40 years from 12 sites (N=9255), participating in the Burden of Obstructive Lung Disease (BOLD) study, poverty was evaluated using a wealth score (0-10) based on household assets. Obstruction, measured as forced expiratory volume in 1 s (FEV 1 )/forced vital capacity (FVC) (%) after administration of 200 μg salbutamol, and prevalence of FEV 1 /FVCwealth scores ranged from 4 in Blantyre (Malawi) and Kashmir (India) to 10 in Riyadh (Saudi Arabia), and the prevalence of obstruction, from 16% in Kashmir to 3% in Riyadh and Penang (Malaysia). Following adjustments for age and sex, FEV 1 /FVC increased by 0.36% (absolute change) (95%CI: 0.22, 0.49; pwealth score. Adjustments for other confounders reduced this effect to 0.23% (0.11, 0.34), but even this value remained highly significant (pwealth scores explained 38% of the variation in mean FEV 1 /FVC between sites (r 2 =0.385, p=0.031).Airflow obstruction is consistently associated with poverty at individual and community levels across several countries. Copyright ©ERS 2017.

A New Blind Pointing Model Improves Large Reflector Antennas Precision Pointing at Ka-Band (32 GHz)

Science.gov (United States)

Rochblatt, David J.

2009-01-01

The National Aeronautics and Space Administration (NASA), Jet Propulsion Laboratory (JPL)-Deep Space Network (DSN) subnet of 34-m Beam Waveguide (BWG) Antennas was recently upgraded with Ka-Band (32-GHz) frequency feeds for space research and communication. For normal telemetry tracking a Ka-Band monopulse system is used, which typically yields 1.6-mdeg mean radial error (MRE) pointing accuracy on the 34-m diameter antennas. However, for the monopulse to be able to acquire and lock, for special radio science applications where monopulse cannot be used, or as a back-up for the monopulse, high-precision open-loop blind pointing is required. This paper describes a new 4th order pointing model and calibration technique, which was developed and applied to the DSN 34-m BWG antennas yielding 1.8 to 3.0-mdeg MRE pointing accuracy and amplitude stability of 0.2 dB, at Ka-Band, and successfully used for the CASSINI spacecraft occultation experiment at Saturn and Titan. In addition, the new 4th order pointing model was used during a telemetry experiment at Ka-Band (32 GHz) utilizing the Mars Reconnaissance Orbiter (MRO) spacecraft while at a distance of 0.225 astronomical units (AU) from Earth and communicating with a DSN 34-m BWG antenna at a record high rate of 6-megabits per second (Mb/s).

A robotic system for 18F-FMISO PET-guided intratumoral pO2 measurements.

Science.gov (United States)

Chang, Jenghwa; Wen, Bixiu; Kazanzides, Peter; Zanzonico, Pat; Finn, Ronald D; Fichtinger, Gabor; Ling, C Clifton

2009-11-01

An image-guided robotic system was used to measure the oxygen tension (pO2) in rodent tumor xenografts using interstitial probes guided by tumor hypoxia PET images. Rats with approximately 1 cm diameter tumors were anesthetized and immobilized in a custom-fabricated whole-body mold. Imaging was performed using a dedicated small-animal PET scanner (R4 or Focus 120 microPET) approximately 2 h after the injection of the hypoxia tracer 18F-fluoromisonidazole (18F-FMISO). The coordinate systems of the robot and PET were registered based on fiducial markers in the rodent bed visible on the PET images. Guided by the 3D microPET image set, measurements were performed at various locations in the tumor and compared to the corresponding 18F-FMISO image intensity at the respective measurement points. Experiments were performed on four tumor-bearing rats with 4 (86), 3 (80), 7 (162), and 8 (235) measurement tracks (points) for each experiment. The 18F-FMISO image intensities were inversely correlated with the measured pO2, with a Pearson coefficient ranging from -0.14 to -0.97 for the 22 measurement tracks. The cumulative scatterplots of pO2 versus image intensity yielded a hyperbolic relationship, with correlation coefficients of 0.52, 0.48, 0.64, and 0.73, respectively, for the four tumors. In conclusion, PET image-guided pO2 measurement is feasible with this robot system and, more generally, this system will permit point-by-point comparison of physiological probe measurements and image voxel values as a means of validating molecularly targeted radiotracers. Although the overall data fitting suggested that 18F-FMISO may be an effective hypoxia marker, the use of static 18F-FMISO PET postinjection scans to guide radiotherapy might be problematic due to the observed high variation in some individual data pairs from the fitted curve, indicating potential temporal fluctuation of oxygen tension in individual voxels or possible suboptimal imaging time postadministration of hypoxia

Automated calibration of laser spectrometer measurements of δ18 O and δ2 H values in water vapour using a Dew Point Generator.

Science.gov (United States)

Munksgaard, Niels C; Cheesman, Alexander W; Gray-Spence, Andrew; Cernusak, Lucas A; Bird, Michael I

2018-06-30

Continuous measurement of stable O and H isotope compositions in water vapour requires automated calibration for remote field deployments. We developed a new low-cost device for calibration of both water vapour mole fraction and isotope composition. We coupled a commercially available dew point generator (DPG) to a laser spectrometer and developed hardware for water and air handling along with software for automated operation and data processing. We characterised isotopic fractionation in the DPG, conducted a field test and assessed the influence of critical parameters on the performance of the device. An analysis time of 1 hour was sufficient to achieve memory-free analysis of two water vapour standards and the δ 18 O and δ 2 H values were found to be independent of water vapour concentration over a range of ≈20,000-33,000 ppm. The reproducibility of the standard vapours over a 10-day period was better than 0.14 ‰ and 0.75 ‰ for δ 18 O and δ 2 H values, respectively (1 σ, n = 11) prior to drift correction and calibration. The analytical accuracy was confirmed by the analysis of a third independent vapour standard. The DPG distillation process requires that isotope calibration takes account of DPG temperature, analysis time, injected water volume and air flow rate. The automated calibration system provides high accuracy and precision and is a robust, cost-effective option for long-term field measurements of water vapour isotopes. The necessary modifications to the DPG are minor and easily reversible. Copyright © 2018 John Wiley & Sons, Ltd.

Re-enrichment of O-18 isotopic water used for the production of F-18 in a cyclotron

International Nuclear Information System (INIS)

Kim, J.; Kim, T.S.; Choi, H.; Jang, D.S.; Jeong, D.Y.

2004-01-01

latter may be more efficient from the system's operational point of view. For a continuous enrichment of the 18 O isotopic water, a 10 stage AGMD cascade system was designed and further information will be presented at the conference

Low-melting point heat transfer fluid

Science.gov (United States)

Cordaro, Joseph Gabriel; Bradshaw, Robert W.

2010-11-09

A low-melting point, heat transfer fluid made of a mixture of five inorganic salts including about 29.1-33.5 mol % LiNO.sub.3, 0-3.9 mol % NaNO.sub.3, 2.4-8.2 mol % KNO.sub.3, 18.6-19.9 mol % NaNO.sub.2, and 40-45.6 mol % KNO.sub.2. These compositions can have liquidus temperatures below 80.degree. C. for some compositions.

Interleukin-18 and interleukin-18 Binding Protein

Directory of Open Access Journals (Sweden)

Charles eDinarello

2013-10-01

Full Text Available Interleukin-18 (IL 18 is a member of the IL 1 family of cytokines. Increasing reports have expanded the role of IL 18 in mediating inflammation in animal models of disease using IL 18 deficient mice, neutralization of IL 18 or deficiency in the IL 18 receptor alpha chain. Similar to IL 1β, IL 18 is synthesized as an inactive precursor requiering processing by caspase 1 into an active cytokine but unlike IL 1β, the IL 18 precursor is constitutively present in nearly all cells in healthy humans and animals. The activity of IL 18 is balanced by the presence of a high-affinity naturally occuring IL 18 binding protein (IL 18BP. In humans, disease increased disease severity can be associated with an imbalance of IL 18 to IL 18BP such that the levels of free IL 18 are elevated in the circulation. A role for IL 18 has been implicated in several autoimmune diseases, myocardial function, emphysema, metabolic syndromes, psoriasis, inflammatory bowel disease, hemophagocytic syndromes, macrophage activation syndrome, sepsis and acute kidney injury, although in some diseases, IL 18 is protective. IL 18 plays a major role in the production of interferon-g from natural killer cells. The IL 18BP has been used safely in humans and clinical trials of IL 18BP as well as neutralizing anti-IL 18 antibodies are in clinical trials. This review updates the biology of IL 18 as well as its role in human disease

A simple solution for model comparison in bold imaging: the special case of reward prediction error and reward outcomes.

Science.gov (United States)

Erdeniz, Burak; Rohe, Tim; Done, John; Seidler, Rachael D

2013-01-01

Conventional neuroimaging techniques provide information about condition-related changes of the BOLD (blood-oxygen-level dependent) signal, indicating only where and when the underlying cognitive processes occur. Recently, with the help of a new approach called "model-based" functional neuroimaging (fMRI), researchers are able to visualize changes in the internal variables of a time varying learning process, such as the reward prediction error or the predicted reward value of a conditional stimulus. However, despite being extremely beneficial to the imaging community in understanding the neural correlates of decision variables, a model-based approach to brain imaging data is also methodologically challenging due to the multicollinearity problem in statistical analysis. There are multiple sources of multicollinearity in functional neuroimaging including investigations of closely related variables and/or experimental designs that do not account for this. The source of multicollinearity discussed in this paper occurs due to correlation between different subjective variables that are calculated very close in time. Here, we review methodological approaches to analyzing such data by discussing the special case of separating the reward prediction error signal from reward outcomes.

The improved syntheses of 5-substituted 2'-[18F]fluoro-2'-deoxy-arabinofuranosyluracil derivatives ([18F]FAU, [18F]FEAU, [18F]FFAU, [18F]FCAU, [18F]FBAU and [18F]FIAU) using a multistep one-pot strategy

International Nuclear Information System (INIS)

Cai Hancheng; Li Zibo; Conti, Peter S.

2011-01-01

Introduction: We and others have previously reported a four-step radiosynthesis of a series of 2'-deoxy-2'-[ 18 F]fluoro-5-substituted-1-β-D-arabinofuranosyluracil derivatives including [ 18 F]FAU, [ 18 F]FEAU, [ 18 F]FFAU, [ 18 F]FCAU, [ 18 F]FBAU and [ 18 F]FIAU as thymidine derivatives for tumor proliferation and/or reporter gene expression imaging with positron emission tomography (PET). Although the radiosynthesis has been proven to be reproducible and efficient, this complicated multistep reaction is difficult to incorporate into an automated cGMP-compliant radiosynthesis module for routine production. Recently, we have developed a simple and efficient one-pot method for routine production of [ 18 F]FMAU. In this study, we studied the feasibility of radiosynthesizing [ 18 F]FAU, [ 18 F]FEAU, [ 18 F]FFAU, [ 18 F]FCAU, [ 18 F]FBAU and [ 18 F]FIAU using this newly developed method. Methods: Similar to the radiosynthesis of [ 18 F]FMAU, 5-substituted 2'-[ 18 F]fluoro-2'-deoxy-arabinofuranosyluracil derivatives ([ 18 F]FAU, [ 18 F]FEAU, [ 18 F]FFAU, [ 18 F]FCAU, [ 18 F]FBAU and [ 18 F]FIAU) were synthesized in one-pot radiosynthesis module in the presence of Friedel-Crafts catalyst TMSOTf and HMDS. Results: This one-pot radiosynthesis method could be used to produce [ 18 F]FAU, [ 18 F]FEAU, [ 18 F]FFAU, [ 18 F]FCAU, [ 18 F]FBAU and [ 18 F]FIAU. The overall radiochemical yields of these tracers varied from 4.1%±0.8% to 10.1%±1.9% (decay-corrected, n=4). The overall reaction time was reduced from 210 min to 150 min from the end of bombardment, and the radiochemical purity was >99%. Conclusions: The improved radiosyntheses of [ 18 F]FAU, [ 18 F]FEAU, [ 18 F]FFAU, [ 18 F]FCAU, [ 18 F]FBAU and [ 18 F]FIAU have been achieved with reasonable yields and high purity using a multistep one-pot method. The synthetic time has been reduced, and the reaction procedures have been significantly simplified. The success of this approach may make PET tracers [ 18 F]FAU, [ 18 F

When water does not boil at the boiling point.

Science.gov (United States)

Chang, Hasok

2007-03-01

Every schoolchild learns that, under standard pressure, pure water always boils at 100 degrees C. Except that it does not. By the late 18th century, pioneering scientists had already discovered great variations in the boiling temperature of water under fixed pressure. So, why have most of us been taught that the boiling point of water is constant? And, if it is not constant, how can it be used as a 'fixed point' for the calibration of thermometers? History of science has the answers.

18 January 2011 - Ing. Vittorio Malacalza, ASG Superconductors S.p.A, Italy in the LHC superconducting magnet test hall with Deputy Department Head L. Rossi, in the LHC tunnel at Point 5 and CMS experimental area with Spokesperson G. Tonelli.

CERN Multimedia

Maximilien Brice

2011-01-01

18 January 2011 - Ing. Vittorio Malacalza, ASG Superconductors S.p.A, Italy in the LHC superconducting magnet test hall with Deputy Department Head L. Rossi, in the LHC tunnel at Point 5 and CMS experimental area with Spokesperson G. Tonelli.

18 December 2013 - P. Kron Chairman and Chief Executive Officer of ALSTOM signing the Guest Book with the Director-General R. Heuer and visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry. Accompanied by P. Fassnacht throughout.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

18 December 2013 - P. Kron Chairman and Chief Executive Officer of ALSTOM signing the Guest Book with the Director-General R. Heuer and visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry. Accompanied by P. Fassnacht throughout.

27 January 2012 - Mitglieder des Stiftungsrates Academia Engelberg und Gesellschaft zum Bettag Luzern Schweiz welcomed by Head of International Relations F. Pauss; visiting LHC tunnel at Point 5 and CMS experimental cavern; in the LHC superconducting magnet test hall SM18.

CERN Multimedia

Maximilien Brice

2012-01-01

27 January 2012 - Mitglieder des Stiftungsrates Academia Engelberg und Gesellschaft zum Bettag Luzern Schweiz welcomed by Head of International Relations F. Pauss; visiting LHC tunnel at Point 5 and CMS experimental cavern; in the LHC superconducting magnet test hall SM18.

Result analysis of area monitoring realized in the 18 MeV cyclotron, during the process of fluorine-18 production; Analise dos resultados do monitoramento de area, realizada no ciclotron de 18 MeV, durante o processo de producao de fluor-18

Energy Technology Data Exchange (ETDEWEB)

Silva, Paula P. Nou; Fernandes, Ivani M.; Silva, Amanda J. da; Rodrigues, Demerval Leonidas; Romero Filho, Christovam R., E-mail: paulanou@usp.b, E-mail: imfernades@ipen.b, E-mail: dlrodri@ipen.b, E-mail: ajsilva@ipen.b, E-mail: cromero@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-10-26

This paper presents the results obtained through the monitoring of circulation area of cyclotron accelerators installation, during the operation for production of fluorine-18. Tis study was based on the data obtained by area monitoring during the year 2009. For determination of the dose rate it was used gamma and neutron radiation detectors. The measurements were performed in nine pre-determined points by the radioprotection team, giving a total of 282 measurements in each point. With the obtained results, it was verified that the area monitoring is accomplishing with his objective which is to now the levels of dose at the work places and, therefore, it is possible to prevent the doses which will be accumulated by the IOEs during the development of their tasks

Reliable quantification of BOLD fMRI cerebrovascular reactivity despite poor breath-hold performance.

Science.gov (United States)

Bright, Molly G; Murphy, Kevin

2013-12-01

Cerebrovascular reactivity (CVR) can be mapped using BOLD fMRI to provide a clinical insight into vascular health that can be used to diagnose cerebrovascular disease. Breath-holds are a readily accessible method for producing the required arterial CO2 increases but their implementation into clinical studies is limited by concerns that patients will demonstrate highly variable performance of breath-hold challenges. This study assesses the repeatability of CVR measurements despite poor task performance, to determine if and how robust results could be achieved with breath-holds in patients. Twelve healthy volunteers were scanned at 3 T. Six functional scans were acquired, each consisting of 6 breath-hold challenges (10, 15, or 20 s duration) interleaved with periods of paced breathing. These scans simulated the varying breath-hold consistency and ability levels that may occur in patient data. Uniform ramps, time-scaled ramps, and end-tidal CO2 data were used as regressors in a general linear model in order to measure CVR at the grey matter, regional, and voxelwise level. The intraclass correlation coefficient (ICC) quantified the repeatability of the CVR measurement for each breath-hold regressor type and scale of interest across the variable task performances. The ramp regressors did not fully account for variability in breath-hold performance and did not achieve acceptable repeatability (ICC0.4). Further analysis of intra-subject CVR variability across the brain (ICCspatial and voxelwise correlation) supported the use of end-tidal CO2 data to extract robust whole-brain CVR maps, despite variability in breath-hold performance. We conclude that the incorporation of end-tidal CO2 monitoring into scanning enables robust, repeatable measurement of CVR that makes breath-hold challenges suitable for routine clinical practice. © 2013.

Aplicación de las tecnologías de la informática y las comunicaciones en la vinculación de los 18 puntos cardinales de la acupuntura con el sistema osteomioarticular Application of the information technologies and knowledge to link up the 18 cardinal points of acupuncture with the osteomyoarticular system

Directory of Open Access Journals (Sweden)

Iraida Hidalgo Gato Castillo

2010-06-01

Full Text Available El objetivo de esta investigación fue elaborar un sistema de medios de enseñanza aplicando las Tecnologías de la Informática y las Comunicaciones (TICs para la vinculación de los 18 puntos cardinales de la acupuntura con los contenidos del sistema osteomioarticular (SOMA que se imparte en la asignatura Morfofisiología Humana II en el primer semestre de Medicina. Dichos medios consistió en un material electrónico de apoyo a la docencia, el que incluyó: 1: Folleto digital donde se propone la distribución de los 18 puntos cardinales de la acupuntura en el sistema osteomioarticular; destacando además el momento oportuno donde se debe realizar la vinculación por parte del profesor, la utilización de los puntos de acupuntura, como terapéutica alternativa y/o enfatizar los conocimientos de la anatomía de superficie. 2: Guía de estudio modelo para la consolidación sobre: esqueleto de los miembros superiores utilizando el modelo WebQuest .3. Secuencia de diapositivas con hipervínculo donde se relacionan los puntos de acupuntura con la anatomía de superficie del esqueleto axil y sus músculos correspondientes, y la de los miembros superiores e inferiores. 4. Ejercicios de autoevaluación vinculando el contenido del sistema osteomioarticular con los puntos cardinales del cuerpo humano en la práctica médica comunitaria. Se concluye que el sistema de medios de enseñanza aplicando las Tecnologías de la Informática y las Comunicaciones (TICs permitirá a los estudiantes establecer las relaciones entre el SOMA y la anatomía de superficie con la acupuntura.The aim of this research was to create a system of teaching aids based on the Information Technologies and Knowledge to link up the 18 cardinal points of acupuncture with the contents of osteomyoarticular system that is taught in the first term of the medical studies through the subject: Human Morphology-2. These teaching aids were compromised of an electronic supporting material to

Blood oxygenation level dependent signal and neuronal adaptation to optogenetic and sensory stimulation in somatosensory cortex in awake animals.

Science.gov (United States)

Aksenov, Daniil P; Li, Limin; Miller, Michael J; Wyrwicz, Alice M

2016-11-01

The adaptation of neuronal responses to stimulation, in which a peak transient response is followed by a sustained plateau, has been well-studied. The blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) signal has also been shown to exhibit adaptation on a longer time scale. However, some regions such as the visual and auditory cortices exhibit significant BOLD adaptation, whereas other such as the whisker barrel cortex may not adapt. In the sensory cortex a combination of thalamic inputs and intracortical activity drives hemodynamic changes, although the relative contributions of these components are not entirely understood. The aim of this study is to assess the role of thalamic inputs vs. intracortical processing in shaping BOLD adaptation during stimulation in the somatosensory cortex. Using simultaneous fMRI and electrophysiology in awake rabbits, we measured BOLD, local field potentials (LFPs), single- and multi-unit activity in the cortex during whisker and optogenetic stimulation. This design allowed us to compare BOLD and haemodynamic responses during activation of the normal thalamocortical sensory pathway (i.e., both inputs and intracortical activity) vs. the direct optical activation of intracortical circuitry alone. Our findings show that whereas LFP and multi-unit (MUA) responses adapted, neither optogenetic nor sensory stimulation produced significant BOLD adaptation. We observed for both paradigms a variety of excitatory and inhibitory single unit responses. We conclude that sensory feed-forward thalamic inputs are not primarily responsible for shaping BOLD adaptation to stimuli; but the single-unit results point to a role in this behaviour for specific excitatory and inhibitory neuronal sub-populations, which may not correlate with aggregate neuronal activity. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

The auriculotemporal nerve in etiology of migraine headaches: compression points and anatomical variations.

Science.gov (United States)

Chim, Harvey; Okada, Haruko C; Brown, Matthew S; Alleyne, Brendan; Liu, Mengyuan T; Zwiebel, Samantha; Guyuron, Bahman

2012-08-01

The auriculotemporal nerve has been identified as one of the peripheral trigger sites for migraine headaches. However, its distal course is poorly mapped following emergence from the parotid gland. In addition, a reliable anatomical landmark for locating the potential compression points along the course of the nerve during surgery has not been sufficiently described. Twenty hemifaces on 10 fresh cadavers were dissected to trace the course of the auriculotemporal nerve from the inferior border of the zygomatic arch to its termination in the temporal scalp. The compression points were mapped and the distances were measured from the most anterosuperior point of the external auditory meatus, which was used as a fixed anatomical landmark. Three potential compression points along the course of the auriculotemporal nerve were identified. Compression points 1 and 2 corresponded to preauricular fascial bands. Compression point 1 was centered 13.1±5.9 mm anterior and 5.0±7.0 mm superior to the most anterosuperior point of the external auditory meatus, whereas compression point 2 was centered at 11.9±6.0 mm anterior and 17.2±10.4 mm superior to the most anterosuperior point of the external auditory meatus. A significant relationship was found between the auriculotemporal nerve and superficial temporal artery (compression point 3) in 80 percent of hemifaces, with three patterns of interaction: a single site of artery crossing over the nerve (62.5 percent), a helical intertwining relationship (18.8 percent), and nerve crossing over the artery (18.8 percent). Findings from this cadaver study provide information relevant to the operative localization of potential compression points along the auriculotemporal nerve.

A new imidazolium-embedded C{sub 18} stationary phase with enhanced performance in reversed-phase liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Qiu Hongdeng [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China); Mallik, Abul K. [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Takafuji, Makoto [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Kumamoto Institute for Photo-Electro Organics (Phoenics), Kumamoto 862-0901 (Japan); Liu Xia; Jiang Shengxiang [Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China); Ihara, Hirotaka, E-mail: ihara@kumamoto-u.ac.jp [Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Kumamoto Institute for Photo-Electro Organics (Phoenics), Kumamoto 862-0901 (Japan)

2012-08-13

Highlights: Black-Right-Pointing-Pointer Imidazolium-embedded C{sub 18} stationary phase was prepared and characterized. Black-Right-Pointing-Pointer Enhanced chromatographic selectivity was observed in SiImC{sub 18} column. Black-Right-Pointing-Pointer Seven nucleosides and bases were separated using only water as eluent within 8 min. Black-Right-Pointing-Pointer Multiple-interactions induced by embedded polar imidazolium was investigated. - Abstract: In this paper, a new imidazolium-embedded C{sub 18} stationary phase (SiImC{sub 18}) for reversed-phase high-performance liquid chromatography is described. 1-Allyl-3-octadecylimidazolium bromide ionic liquid compound having a long alkyl chain and reactive groups was newly prepared and grafted onto 3-mercaptopropyltrimethoxysilane-modified silica via a surface-initiated radical-chain transfer addition reaction. The SiImC{sub 18} obtained was characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, diffuse reflectance infrared Fourier transform, and solid-state {sup 13}C and {sup 29}Si cross-polarization/magic angle spinning nuclear magnetic resonance spectroscopy. The selectivity toward polycyclic aromatic hydrocarbons relative to that toward alkylbenzenes exhibited by SiImC{sub 18} was higher than the corresponding selectivity exhibited by a conventional octadecyl silica (ODS) column, which could be explained by electrostatic {pi}-{pi} interaction cationic imidazolium and electron-rich aromatic rings. On the other hand, SiImC{sub 18} also showed high selectivity for polar compounds, which was based on the multiple interaction and retention mechanisms of this phase with different analytes. 1,6-Dinitropyrene and 1,8-dinitropyrene, which form a positional isomer pair of dipolar compounds, were separated successfully with the SiImC{sub 18} phase. Seven nucleosides and bases (i.e. cytidine, uracil, uridine, thymine, guanosine, xanthosine, and adenosine) were separated using only water as

Genetic variability of Rickettsia spp. in Ixodes persulcatus ticks from continental and island areas of the Russian Far East.

Science.gov (United States)

Igolkina, Y; Bondarenko, E; Rar, V; Epikhina, T; Vysochina, N; Pukhovskaya, N; Tikunov, A; Ivanov, L; Golovljova, I; Ivanov, М; Tikunova, N

2016-10-01

Rickettsia spp. are intracellular Gram-negative bacteria transmitted by arthropods. Two potentially pathogenic rickettsiae, Candidatus Rickettsia tarasevichiae and Rickettsia helvetica, have been found in unfed adult Ixodes persulcatus ticks. The aim of this study was to assess the prevalence and genetic variability of Rickettsia spp. in I. persulcatus ticks collected from different locations in the Russian Far East. In total, 604 adult I. persulcatus ticks collected from four sites in the Khabarovsk Territory (continental area) and one site in Sakhalin Island were examined for the presence of Rickettsia spp. by real-time PCR. Nested PCR with species-specific primers and sequencing were used for genotyping of revealed rickettsiae. The overall prevalence of Rickettsia spp. in ticks collected in different sites varied from 67.9 to 90.7%. However, the proportion of different Rickettsia species observed in ticks from Sakhalin Island significantly differed from that in ticks from the Khabarovsk Territory. In Sakhalin Island, R. helvetica prevailed in examined ticks, while Candidatus R. tarasevichiae was predominant in the Khabarovsk Territory. For gltA and ompB gene fragments, the sequences obtained for Candidatus R. tarasevichiae from all studied sites were identical to each other and to the known sequences of this species. According to sequence analysis of gltA, оmpB and sca4 genes, R. helvetica isolates from Sakhalin Island and the Khabarovsk Territory were identical to each other, but they differed from R. helvetica from other regions and from those found in other tick species. For the first time, DNA of pathogenic Rickettsia heilongjiangensis was detected in I. persulcatus ticks in two sites from the Khabarovsk Territory. The gltA, ompA and оmpB gene sequences of R. heilongjiangensis were identical to or had solitary mismatches with the corresponding sequences of R. heilongjiangensis found in other tick species. Copyright © 2016 Elsevier GmbH. All rights

When BOLD is thicker than water: processing social information about kin and friends at different levels of the social network.

Science.gov (United States)

Wlodarski, Rafael; Dunbar, Robin I M

2016-12-01

The aim of this study was to examine differences in the neural processing of social information about kin and friends at different levels of closeness and social network level. Twenty-five female participants engaged in a cognitive social task involving different individuals in their social network while undergoing functional magnetic resonance imaging scanning to detect BOLD (Blood Oxygen Level Dependent) signals changes. Greater levels of activation occurred in several regions of the brain previously associated with social cognition when thinking about friends than when thinking about kin, including the posterior cingulate cortex (PCC) and the ventral medial prefrontal cortex (vMPFC). Linear parametric analyses across network layers further showed that, when it came to thinking about friends, activation increased in the vMPFC, lingual gyrus, and sensorimotor cortex as individuals thought about friends at closer layers of the network. These findings suggest that maintaining friendships may be more cognitively exacting than maintaining kin relationships. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Coloring problem and magnetocaloric effect of Gd{sub 3}Co{sub 2.2}Si{sub 1.8}

Energy Technology Data Exchange (ETDEWEB)

Yao, Jinlei, E-mail: materyao@gmail.com [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Morozkin, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Mozharivskyj, Yurij [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada)

2013-02-15

Highlights: Black-Right-Pointing-Pointer Gd{sub 3}Co{sub 2.2}Si{sub 1.8} adopts the Er{sub 3}Ge{sub 4} structure (space group Cmcm). Black-Right-Pointing-Pointer Si and Co show site preference. Black-Right-Pointing-Pointer The electronic factors determine the site occupation of Si and Co. Black-Right-Pointing-Pointer Gd{sub 3}Co{sub 2.2}Si{sub 1.8} order ferromagnetically below 172 K. - Abstract: The Gd{sub 3}Co{sub 2.2}Si{sub 1.8} compound was synthesized by arc melting the constituent elements and subsequent annealing at 1070 K for 120 h. It adopts the Dy{sub 3}Co{sub 2.2}Si{sub 1.8}-type structure with the space group Cmcm and the unit cell parameters of a = 4.1176(7) A, b = 10.305(2) A, c = 12.778(2) A and V = 542.2(2) A{sup 3}. The Co and Si atoms preferentially occupy the 8f and 4a/4c sites, respectively. The atomic electronegativity and electron density at a given site determine its site occupation, according to the analysis of the electronic structure. Gd{sub 3}Co{sub 2.2}Si{sub 1.8} orders ferromagnetically with the Curie temperature of 172 K. The isothermal magnetic entropy change, -{Delta}S{sub m}, reaches the maximum value of 7.09 J/kg K at 170 K for a field change of 0-50 kOe.

Eigenvectors and fixed point of non-linear operators

Directory of Open Access Journals (Sweden)

Giulio Trombetta

2007-12-01

Full Text Available Let X be a real infinite-dimensional Banach space and ψ a measure of noncompactness on X. Let Ω be a bounded open subset of X and A : Ω → X a ψ-condensing operator, which has no fixed points on ∂Ω.Then the fixed point index, ind(A,Ω, of A on Ω is defined (see, for example, ([1] and [18]. In particular, if A is a compact operator ind(A,Ω agrees with the classical Leray-Schauder degree of I −A on Ω relative to the point 0, deg(I −A,Ω,0. The main aim of this note is to investigate boundary conditions, under which the fixed point index of strict- ψ-contractive or ψ-condensing operators A : Ω → X is equal to zero. Correspondingly, results on eigenvectors and nonzero fixed points of k-ψ-contractive and ψ-condensing operators are obtained. In particular we generalize the Birkhoff-Kellog theorem [4] and Guo’s domain compression and expansion theorem [17]. The note is based mainly on the results contained in [7] and [8].

17 CFR 240.14d-103 - Schedule 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the...

Science.gov (United States)

2010-04-01

... legibility requirements for the required legends relating to type size and font by presenting the legend in... home jurisdiction document(s) in bold-face roman type at least as high as ten-point modern type and at...

Nalmefene Reduces Reward Anticipation in Alcohol Dependence: An Experimental Functional Magnetic Resonance Imaging Study.

Science.gov (United States)

Quelch, Darren R; Mick, Inge; McGonigle, John; Ramos, Anna C; Flechais, Remy S A; Bolstridge, Mark; Rabiner, Eugenii; Wall, Matthew B; Newbould, Rexford D; Steiniger-Brach, Björn; van den Berg, Franz; Boyce, Malcolm; Østergaard Nilausen, Dorrit; Breuning Sluth, Lasse; Meulien, Didier; von der Goltz, Christoph; Nutt, David; Lingford-Hughes, Anne

2017-06-01

Nalmefene is a µ and δ opioid receptor antagonist, κ opioid receptor partial agonist that has recently been approved in Europe for treating alcohol dependence. It offers a treatment approach for alcohol-dependent individuals with "high-risk drinking levels" to reduce their alcohol consumption. However, the neurobiological mechanism underpinning its effects on alcohol consumption remains to be determined. Using a randomized, double-blind, placebo-controlled, within-subject crossover design we aimed to determine the effect of a single dose of nalmefene on striatal blood oxygen level-dependent (BOLD) signal change during anticipation of monetary reward using the monetary incentive delay task following alcohol challenge. Twenty-two currently heavy-drinking, non-treatment-seeking alcohol-dependent males were recruited. The effect of single dose nalmefene (18 mg) on changes in a priori defined striatal region of interest BOLD signal change during reward anticipation compared with placebo was investigated using functional magnetic resonance imaging. Both conditions were performed under intravenous alcohol administration (6% vol/vol infusion to achieve a target level of 80 mg/dL). Datasets from 18 participants were available and showed that in the presence of the alcohol infusion, nalmefene significantly reduced the BOLD response in the striatal region of interest compared with placebo. Nalmefene did not alter brain perfusion. Nalmefene blunts BOLD response in the mesolimbic system during anticipation of monetary reward and an alcohol infusion. This is consistent with nalmefene's actions on opioid receptors, which modulate the mesolimbic dopaminergic system, and provides a neurobiological basis for its efficacy. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Study of some excited states in 21Ne-21Na, 18O-18F and 15N-15O nuclei

International Nuclear Information System (INIS)

Drain, D.

1977-01-01

The study of 21 Ne- 21 Na, 18 O- 18 F and 15 N- 15 O nuclei was performed through proton capture and transfer reactions and allows to determine the spins and parities of some excited states, give the gamma deexcitation schemes of these levels, compute the neutron and proton reduced width γ 2 sub(n) and γ 2 sub(p). The levels studied are: in 21 Na 4.15 20 Ne(p,p), (p,p'), (p,p'γ) and (pγ) reactions) and in 21 Ne: E(exc)=4.73, 5.69 and 5.78 MeV ( 20 Ne (p,p) reaction); in 18 O: E(exc) 17 O(d,p) reaction); in 15 O: 8.92 MeV doublet and 8.98 MeV level (angular correlation 14 N(p,γγ) and in 15 N: 9.05 14 N(d,p) reaction). A comparison with theoretical results is discussed and analog states are pointed out [fr

Bold-functional MRI study of the abnormal cortex and the relationship between the inpairment of vision and the decreased activation of the visual cortex in anisometropic amblyopia

International Nuclear Information System (INIS)

Wang Jian; Li Chuanming; Zhou Yang; Xie Bing; Yu Qiongwu; Wang Hui; Qiu Mingguo; Weng Xuchu

2006-01-01

Objective: To assess the activation changes on Brodmann areas 17, 18 and 19 in anisometropic amblyopia and compare the features of the cortex activations before and after refractive correction on amblyopic eyes. Methods: Bold-fMRI technique on 1.5 T Simens Sonata MRI and the blocks designation mode was used. The visual stimulation task was a black and white checkerboard with frequencies of 1 cycle/degree and 8 Hz. The baseline stimulus is a white cross-line at the center of the screen with black background. No other light or influence was allowed in the scanning room. The distance between the eyes and screen was 0.6 m. The experimental group included 10 anisometropic amblyopes. TSE and EPI sequence were used for the anatomical and functional data acquisitions. For experimental group, the activation areas of the visual cortex on both eyes were consequently measured before and after refractive correction. All data were analyzed online with t-test and offline with AFNI software. The threshold value was set to 0.001. During data processing, motion correction and three-dimensional smooth were used in all data. The time-signal intensity curves and the functional images were obtained. After Talairach coordinated the function images of every one, the activation areas were measured in Brodmann areas 17, 18 and 19. The SPSS 12.0 software was used for statistic analysis. The difference of the cortical activations of amblyopic eyes before and after refractive correction was analyzed. The cortical activations of amblyopic eyes and the fellow eyes after refractive correction were compared. The visual acuity of the amblyopia eyes was measured. And the correlation between the lesion of cortical activation and visual acuity was analyzed. Results: It was found that the cortex was activated obviously in the calcarine cortex around, occipital lobe, LGN and temporal lobe. The activation areas of amblyopic eyes was (3.7±0.4) x 10 4 voxels, and (4.1±0.5 ) x 10 4 voxets after corrected

Study of asymmetry in motor areas related to handedness using the fMRI BOLD response Gaussian convolution model

Energy Technology Data Exchange (ETDEWEB)

Gao Qing [School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); School of Applied Mathematics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Chen Huafu [School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); School of Applied Mathematics, University of Electronic Science and Technology of China, Chengdu 610054 (China)], E-mail: Chenhf@uestc.edu.cn; Gong Qiyong [Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041 (China)

2009-10-30

Brain asymmetry is a phenomenon well known for handedness, and has been studied in the motor cortex. However, few studies have quantitatively assessed the asymmetrical cortical activities for handedness in motor areas. In the present study, we systematically and quantitatively investigated asymmetry in the left and right primary motor cortices during sequential finger movements using the Gaussian convolution model approach based on the functional magnetic resonance imaging (fMRI) blood oxygenation level dependent (BOLD) response. Six right-handed and six left-handed subjects were recruited to perform three types of hand movement tasks. The results for the expected value of the Gaussian convolution model showed that it took the dominant hand a longer average interval of response delay regardless of the handedness and bi- or uni-manual performance. The results for the standard deviation of the Gaussian model suggested that in the mass neurons, these intervals of the dominant hand were much more variable than those of the non-dominant hand. When comparing bi-manual movement conditions with uni-manual movement conditions in the primary motor cortex (PMC), both the expected value and standard deviation in the Gaussian function were significantly smaller (p < 0.05) in the bi-manual conditions, showing that the movement of the non-dominant hand influenced that of the dominant hand.

Study of asymmetry in motor areas related to handedness using the fMRI BOLD response Gaussian convolution model

International Nuclear Information System (INIS)

Gao Qing; Chen Huafu; Gong Qiyong

2009-01-01

Brain asymmetry is a phenomenon well known for handedness, and has been studied in the motor cortex. However, few studies have quantitatively assessed the asymmetrical cortical activities for handedness in motor areas. In the present study, we systematically and quantitatively investigated asymmetry in the left and right primary motor cortices during sequential finger movements using the Gaussian convolution model approach based on the functional magnetic resonance imaging (fMRI) blood oxygenation level dependent (BOLD) response. Six right-handed and six left-handed subjects were recruited to perform three types of hand movement tasks. The results for the expected value of the Gaussian convolution model showed that it took the dominant hand a longer average interval of response delay regardless of the handedness and bi- or uni-manual performance. The results for the standard deviation of the Gaussian model suggested that in the mass neurons, these intervals of the dominant hand were much more variable than those of the non-dominant hand. When comparing bi-manual movement conditions with uni-manual movement conditions in the primary motor cortex (PMC), both the expected value and standard deviation in the Gaussian function were significantly smaller (p < 0.05) in the bi-manual conditions, showing that the movement of the non-dominant hand influenced that of the dominant hand.

Radiation dosimetry estimates of [{sup 18}F]-fluoroacetate based on biodistribution data of rats

Energy Technology Data Exchange (ETDEWEB)

Zhang Jianping [Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Zhang Yingjian, E-mail: yjzhang111@yahoo.com.cn [Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Xu Junyan; Yang Zhongyi [Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China)

2012-01-15

We estimated the dosimetry of [{sup 18}F]fluoroacetate (FAC) with the method established by MIRD based on biodistribution data of rats. We selected some important organs and computed their residence time, their absorbed doses and effective dose with the (%ID{sub Organ}) {sub human} data using OLINDA/EXM 1.1 program. We observed the highest absorbed doses in the heart wall (0.025 mGy/MBq) and the lowest in skin (0.0079 mGy/MBq). The total mean absorbed doses and the effective doses were 0.011 mGy/MBq and 0.014 mSv/MBq, respectively. A 370-MBq injection of FAC leads to an estimated effective dose of 5.2 mSv. The potential radiation risk associated with FAC/PET imaging is well within the accepted limits. - Highlights: Black-Right-Pointing-Pointer We demonstrate a proper model to estimate the absorbed dose and effective dose of normal human. Black-Right-Pointing-Pointer Dosimetry of [{sup 18}F]-Fluoroacetate was estimated in human based on biodistribution of rats. Black-Right-Pointing-Pointer A 370 MBq injection of [{sup 18}F]-Fluoroacetate leads to an estimated effective dose of 5.2 mSv.

Fatigue crack initiation – The role of point defects

Czech Academy of Sciences Publication Activity Database

Polák, Jaroslav; Man, Jiří

2014-01-01

Roč. 65, AUG (2014), s. 18-27 ISSN 0142-1123 R&D Projects: GA ČR(CZ) GAP108/10/2371; GA ČR(CZ) GA13-23652S Institutional support: RVO:68081723 Keywords : Fatigue crack initiation * Point defects * Persistent slip band * Intrusion * Extrusion Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.275, year: 2014

Microbial profile and critical control points during processing of 'robo ...

African Journals Online (AJOL)

STORAGESEVER

2009-05-18

May 18, 2009 ... frying, surface fat draining, open-air cooling, and holding/packaging in polyethylene films during sales and distribution. The product was, however, classified under category III with respect to risk and the significance of monitoring and evaluation of quality using the hazard analysis critical control point.

Communication ability in persons with trisomy 18 and trisomy 13.

Science.gov (United States)

Braddock, Barbara; McDaniel, Jena; Spragge, Sara; Loncke, Filip; Braddock, Stephen R; Carey, John C

2012-12-01

The purpose of this study was to assess communication abilities among a sample of 10 individuals with Trisomy 18 and Trisomy 13. These 10 individuals were diagnosed with Trisomy 18 (n = 8) or Trisomy 13 (n = 2) and had a mean age of 15.96 years. The sample consisted of one male and nine females. Caregivers completed a case history and reported on words and gestures understood and/or produced. Participants were also videotaped during communication temptation tasks. Auditory comprehension was reported to be higher than expressive language. No participant produced intelligible words or word approximations, yet most produced hand gestures. The process and results of these 10 cases point to a potentially promising approach for assessing communication abilities in individuals with Trisomy 18 and Trisomy 13.

Tritium in [18O]water containing [18F]fluoride for [18F]FDG synthesis

International Nuclear Information System (INIS)

Ito, Shigeki; Saze, Takuya; Sakane, Hitoshi; Ito, Satoshi; Ito, Shinichi; Nishizawa, Kunihide

2004-01-01

The presence of tritium in enriched [ 18 O]water irradiated with 9.6 MeV protons used to produce [ 18 F]fluoride by the 18 O(p, n) 18 F reaction was inferred from the cross sections and threshold energies of the 18 O(p, t) 16 O reaction, and the existence of tritium was confirmed experimentally. Tritium was also detected in both [ 18 O]water recovered for recycling and waste acetonitrile solutions. The purified [ 18 F]FDG was not contaminated with 3 H. The amount of 3 H discharged into the air was far less than the International Basic Safety Standard Level

Post-synthetic transformation of a Zn( ii ) polyhedral coordination network into a new supramolecular isomer of HKUST-1

Energy Technology Data Exchange (ETDEWEB)

Chen, Yao [State Key Laboratory of Medicinal Chemical Biology; Nankai University; Tianjin 300071; P. R. China; College of Pharmacy; Wojtas, Lukasz [Department of Chemistry; University of South Florida; 4202 East Fowler Avenue; Tampa; USA; Ma, Shengqian [Department of Chemistry; University of South Florida; 4202 East Fowler Avenue; Tampa; USA; Zaworotko, Michael J. [Department of Chemistry & Environmental Sciences, Bernal Institute, University of Limerick; Limerick; Republic of Ireland; Zhang, Zhenjie [College of Chemistry, Nankai University; Tianjin; P. R. China; State Key Laboratory of Medicinal Chemical Biology; Nankai University

2017-01-01

A Zn-based porphyrin containing metal–organic material (<bold>porphMOM-1bold>) was post-synthetically transformed into a Cu-based porphyrin-encapsulating metal–organic material (<bold>porph@HKUST-1-βbold>).>HKUST-1-βbold>is a new supramolecular isomer of<bold>HKUST-1bold>.

Power Trip Set-points of Reactor Protection System for New Research Reactor

International Nuclear Information System (INIS)

Lee, Byeonghee; Yang, Soohyung

2013-01-01

This paper deals with the trip set-point related to the reactor power considering the reactivity induced accident (RIA) of new research reactor. The possible scenarios of reactivity induced accidents were simulated and the effects of trip set-point on the critical heat flux ratio (CHFR) were calculated. The proper trip set-points which meet the acceptance criterion and guarantee sufficient margins from normal operation were then determined. The three different trip set-points related to the reactor power are determined based on the RIA of new research reactor during FP condition, over 0.1%FP and under 0.1%FP. Under various reactivity insertion rates, the CHFR are calculated and checked whether they meet the acceptance criterion. For RIA at FP condition, the acceptance criterion can be satisfied even if high power set-point is only used for reactor trip. Since the design of the reactor is still progressing and need a safety margin for possible design changes, 18 MW is recommended as a high power set-point. For RIA at 0.1%FP, high power setpoint of 18 MW and high log rate of 10%pp/s works well and acceptance criterion is satisfied. For under 0.1% FP operations, the application of high log rate is necessary for satisfying the acceptance criterion. Considering possible decrease of CHFR margin due to design changes, the high log rate is suggested to be 8%pp/s. Suggested trip set-points have been identified based on preliminary design data for new research reactor; therefore, these trip set-points will be re-established by considering design progress of the reactor. The reactor protection system (RPS) of new research reactor is designed for safe shutdown of the reactor and preventing the release of radioactive material to environment. The trip set point of RPS is essential for reactor safety, therefore should be determined to mitigate the consequences from accidents. At the same time, the trip set-point should secure margins from normal operational condition to avoid

Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the USS BOLD in the Gulf of Mexico from 2006-06-06 to 2006-09-11 (NODC Accession 0117493)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0117493 includes Surface underway, chemical, meteorological and physical data collected from USS BOLD in the Gulf of Mexico from 2006-06-06 to...

Regional Reproducibility of BOLD Calibration Parameter M, OEF and Resting-State CMRO2 Measurements with QUO2 MRI.

Directory of Open Access Journals (Sweden)

Isabelle Lajoie

Full Text Available The current generation of calibrated MRI methods goes beyond simple localization of task-related responses to allow the mapping of resting-state cerebral metabolic rate of oxygen (CMRO2 in micromolar units and estimation of oxygen extraction fraction (OEF. Prior to the adoption of such techniques in neuroscience research applications, knowledge about the precision and accuracy of absolute estimates of CMRO2 and OEF is crucial and remains unexplored to this day. In this study, we addressed the question of methodological precision by assessing the regional inter-subject variance and intra-subject reproducibility of the BOLD calibration parameter M, OEF, O2 delivery and absolute CMRO2 estimates derived from a state-of-the-art calibrated BOLD technique, the QUantitative O2 (QUO2 approach. We acquired simultaneous measurements of CBF and R2* at rest and during periods of hypercapnia (HC and hyperoxia (HO on two separate scan sessions within 24 hours using a clinical 3 T MRI scanner. Maps of M, OEF, oxygen delivery and CMRO2, were estimated from the measured end-tidal O2, CBF0, CBFHC/HO and R2*HC/HO. Variability was assessed by computing the between-subject coefficients of variation (bwCV and within-subject CV (wsCV in seven ROIs. All tests GM-averaged values of CBF0, M, OEF, O2 delivery and CMRO2 were: 49.5 ± 6.4 mL/100 g/min, 4.69 ± 0.91%, 0.37 ± 0.06, 377 ± 51 μmol/100 g/min and 143 ± 34 μmol/100 g/min respectively. The variability of parameter estimates was found to be the lowest when averaged throughout all GM, with general trends toward higher CVs when averaged over smaller regions. Among the MRI measurements, the most reproducible across scans was R2*0 (wsCVGM = 0.33% along with CBF0 (wsCVGM = 3.88% and R2*HC (wsCVGM = 6.7%. CBFHC and R2*HO were found to have a higher intra-subject variability (wsCVGM = 22.4% and wsCVGM = 16% respectively, which is likely due to propagation of random measurement errors, especially for CBFHC due to the

In vivo evaluation of 2'-deoxy-2'-[{sup 18}F]fluoro-5-iodo-1-{beta}-D-arabinofuranosyluracil ([{sup 18}F]FIAU) and 2'-deoxy-2'-[{sup 18}F]fluoro-5-ethyl-1-{beta}-D-arabinofuranosyluracil ([{sup 18}F]FEAU) as markers for suicide gene expression

Energy Technology Data Exchange (ETDEWEB)

Alauddin, Mian M. [University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd. T8.3895, P.O. Box 059, Houston, TX (United States); Shahinian, Antranic; Park, Ryan; Fissekis, John D.; Conti, Peter S. [University of Southern California, PET Imaging Science Center, Keck School of Medicine, Los Angeles, CA (United States); Tohme, Michel [University of Southern California, PET Imaging Science Center, Keck School of Medicine, Los Angeles, CA (United States); Department of Biomedical Engineering, UC Davis, Davis, CA (United States)

2007-06-15

FIAU and FEAU were evaluated in vitro and in vivo as markers for HSV1-tk gene expression. In vitro and biodistribution studies were performed in wild type and transduced HT-29 cells using [{sup 14}C]FIAU and [{sup 3}H]FEAU. PET imaging was performed using [{sup 18}F]FIAU and [{sup 18}F]FEAU. In vitro uptake of [{sup 14}C]FIAU in tk-positive cells was 39-fold, 49-fold, and 43-fold higher (p < 0.001) than in wild type cells at 30, 60, and 120 min, respectively. Uptake of [{sup 3}H]FEAU in transduced cells was 46-fold, 62-fold, and 121-fold higher (p < 0.001) than in wild type cells at the same time points. In vivo uptake of [{sup 14}C]FIAU at 2 h in HSV1-tk positive tumors was 15.48 {+-} 3.94, 6.7-fold higher (p < 0.001) than in wild type tumors. Uptake of [{sup 3}H]FEAU in transduced tumors was 9.98 {+-} 1.99, 5.0-fold higher (p < 0.001) than in wild type tumors. Micro-PET images using [{sup 18}F]FIAU and [{sup 18}F]FEAU also showed very high uptake in HSV-tk tumors. [{sup 18}F]FIAU and [{sup 18}F]FEAU appear to be potential PET imaging agents for gene expression. (orig.)

Fatty acid composition of commercially available Iranian edible oils

Directory of Open Access Journals (Sweden)

Sedigheh Asgary

2009-08-01

Full Text Available Bold" size="1">Bold" size="1">

• BACKGROUND: Trans-fatty acids (TFAs, unsaturated fats with at least one double bond in the Trans configuration, are industrially formed in large quantities when vegetable oils are partially hydrogenated. This study was  ndertaken to quantify the amounts of the common fatty acids in several commercial oils marketing in Iran.
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• METHODS: The most consumed commercially available brands of vegetable oils were randomly selected from products available in supermarkets. A 10g sample was drawn from each mixed sample and prepared for fatty cid analysis by gas chromatography (GC.
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• RESULTS: Palmitic acid (C16:0 and stearic acid (C18:0 jointly constituted 21% of total fatty acids in partially hydrogenated vegetable oils (PHVOs. More than one third of total fatty acids in Iranian PHVOs were Trans fats. TFAs constituted almost 1% and 3% of total fatty  cids in Iranian cooking and frying oils. This study  howed higher contents of TFAs in Iranian commercially available hydrogenated vegetable oils. Statistical Package for Social Sciences was used for all statistical analyses.
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• CONCLUSIONS: Although

• Point group invariants in the Uqp(u(2)) quantum algebra picture

  International Nuclear Information System (INIS)

  Kibler, M.

  1993-07-01

  Some consequences of a qp-quantization of a point group invariant developed in the enveloping algebra of SU(2) are examined. A set of open problems concerning such invariants in the U qp (u(2)) quantum algebra picture is briefly discussed. (author) 18 refs

• The flavoprotein Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells

  Energy Technology Data Exchange (ETDEWEB)

  Nishimura, Akira; Kawahara, Nobuhiro [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Takagi, Hiroshi, E-mail: hiro@bs.naist.jp [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)

  2013-01-04

  Highlights: Black-Right-Pointing-Pointer NO is produced from L-arginine in response to elevated temperature in yeast. Black-Right-Pointing-Pointer Tah18 was first identified as the yeast protein involved in NO synthesis. Black-Right-Pointing-Pointer Tah18-dependent NO synthesis confers tolerance to high-temperature on yeast cells. -- Abstract: Nitric oxide (NO) is a ubiquitous signaling molecule involved in the regulation of a large number of cellular functions. In the unicellular eukaryote yeast, NO may be involved in stress response pathways, but its role is poorly understood due to the lack of mammalian NO synthase (NOS) orthologues. Previously, we have proposed the oxidative stress-induced L-arginine synthesis and its physiological role under stress conditions in yeast Saccharomyces cerevisiae. Here, our experimental results indicated that increased conversion of L-proline into L-arginine led to NO production in response to elevated temperature. We also showed that the flavoprotein Tah18, which was previously reported to transfer electrons to the Fe-S cluster protein Dre2, was involved in NO synthesis in yeast. Gene knockdown analysis demonstrated that Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells. As it appears that such a unique cell protection mechanism is specific to yeasts and fungi, it represents a promising target for antifungal activity.

• 17 CFR 230.420 - Legibility of prospectus.

  Science.gov (United States)

  2010-04-01

  ... size, type size and font, bold-face type, italics and red ink, by presenting all required information... data included therein shall be in roman type at least as large and as legible as 10-point modern type... rule 482 (17 CFR 230.482) may be in roman type at least as large and as legible as 8-point modern type...