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Sample records for cortical hubs revealed

  1. Cortical Hubs Revealed by Intrinsic Functional Connectivity: Mapping, Assessment of Stability, and Relation to Alzheimer’s Disease

    PubMed Central

    Buckner, Randy L.; Sepulcre, Jorge; Talukdar, Tanveer; Krienen, Fenna; Liu, Hesheng; Hedden, Trey; Andrews-Hanna, Jessica R.; Sperling, Reisa A.; Johnson, Keith A.

    2009-01-01

    Recent evidence suggests that some brain areas act as hubs interconnecting distinct, functionally-specialized systems. These nexuses are intriguing because of their potential role in integration and also because they may augment metabolic cascades relevant to brain disease. To identify regions of high connectivity in the human cerebral cortex, we applied a computationally-efficient approach to map the degree of intrinsic functional connectivity across the brain. Analysis of two separate fMRI datasets (each n=24) demonstrated hubs throughout heteromodal areas of association cortex. Prominent hubs were located within posterior cingulate, lateral temporal, lateral parietal, and medial/lateral prefrontal cortices. Network analysis revealed that many, but not all, hubs were located within regions previously implicated as components of the default network. A third dataset (n=12) demonstrated that the locations of hubs were present across passive and active task states suggesting that they reflect a stable property of cortical network architecture. To obtain an accurate reference map, data were combined across 127 participants to yield a consensus estimate of cortical hubs. Using this consensus estimate, we explored whether the topography of hubs could explain the pattern of vulnerability in Alzheimer’s disease (AD) as some models suggest that regions of high activity and metabolism accelerate pathology. PET amyloid imaging in AD (n=10) as compared to older controls (n=29) showed high Aβ deposition in the locations of cortical hubs consistent with the possibility that hubs, while acting as critical waystations for information processing, may also augment the underlying pathological cascade in AD. PMID:19211893

  2. Functional Clusters, Hubs, and Communities in the Cortical Microconnectome

    PubMed Central

    Shimono, Masanori; Beggs, John M.

    2015-01-01

    Although relationships between networks of different scales have been observed in macroscopic brain studies, relationships between structures of different scales in networks of neurons are unknown. To address this, we recorded from up to 500 neurons simultaneously from slice cultures of rodent somatosensory cortex. We then measured directed effective networks with transfer entropy, previously validated in simulated cortical networks. These effective networks enabled us to evaluate distinctive nonrandom structures of connectivity at 2 different scales. We have 4 main findings. First, at the scale of 3–6 neurons (clusters), we found that high numbers of connections occurred significantly more often than expected by chance. Second, the distribution of the number of connections per neuron (degree distribution) had a long tail, indicating that the network contained distinctively high-degree neurons, or hubs. Third, at the scale of tens to hundreds of neurons, we typically found 2–3 significantly large communities. Finally, we demonstrated that communities were relatively more robust than clusters against shuffling of connections. We conclude the microconnectome of the cortex has specific organization at different scales, as revealed by differences in robustness. We suggest that this information will help us to understand how the microconnectome is robust against damage. PMID:25336598

  3. Cortical hubs form a module for multisensory integration on top of the hierarchy of cortical networks.

    PubMed

    Zamora-López, Gorka; Zhou, Changsong; Kurths, Jürgen

    2010-01-01

    Sensory stimuli entering the nervous system follow particular paths of processing, typically separated (segregated) from the paths of other modal information. However, sensory perception, awareness and cognition emerge from the combination of information (integration). The corticocortical networks of cats and macaque monkeys display three prominent characteristics: (i) modular organisation (facilitating the segregation), (ii) abundant alternative processing paths and (iii) the presence of highly connected hubs. Here, we study in detail the organisation and potential function of the cortical hubs by graph analysis and information theoretical methods. We find that the cortical hubs form a spatially delocalised, but topologically central module with the capacity to integrate multisensory information in a collaborative manner. With this, we resolve the underlying anatomical substrate that supports the simultaneous capacity of the cortex to segregate and to integrate multisensory information.

  4. Cortical Hubs Form a Module for Multisensory Integration on Top of the Hierarchy of Cortical Networks

    PubMed Central

    Zamora-López, Gorka; Zhou, Changsong; Kurths, Jürgen

    2009-01-01

    Sensory stimuli entering the nervous system follow particular paths of processing, typically separated (segregated) from the paths of other modal information. However, sensory perception, awareness and cognition emerge from the combination of information (integration). The corticocortical networks of cats and macaque monkeys display three prominent characteristics: (i) modular organisation (facilitating the segregation), (ii) abundant alternative processing paths and (iii) the presence of highly connected hubs. Here, we study in detail the organisation and potential function of the cortical hubs by graph analysis and information theoretical methods. We find that the cortical hubs form a spatially delocalised, but topologically central module with the capacity to integrate multisensory information in a collaborative manner. With this, we resolve the underlying anatomical substrate that supports the simultaneous capacity of the cortex to segregate and to integrate multisensory information. PMID:20428515

  5. Plasma membrane domains enriched in cortical endoplasmic reticulum function as membrane protein trafficking hubs.

    PubMed

    Fox, Philip D; Haberkorn, Christopher J; Weigel, Aubrey V; Higgins, Jenny L; Akin, Elizabeth J; Kennedy, Matthew J; Krapf, Diego; Tamkun, Michael M

    2013-09-01

    In mammalian cells, the cortical endoplasmic reticulum (cER) is a network of tubules and cisterns that lie in close apposition to the plasma membrane (PM). We provide evidence that PM domains enriched in underlying cER function as trafficking hubs for insertion and removal of PM proteins in HEK 293 cells. By simultaneously visualizing cER and various transmembrane protein cargoes with total internal reflectance fluorescence microscopy, we demonstrate that the majority of exocytotic delivery events for a recycled membrane protein or for a membrane protein being delivered to the PM for the first time occur at regions enriched in cER. Likewise, we observed recurring clathrin clusters and functional endocytosis of PM proteins preferentially at the cER-enriched regions. Thus the cER network serves to organize the molecular machinery for both insertion and removal of cell surface proteins, highlighting a novel role for these unique cellular microdomains in membrane trafficking.

  6. K-shell decomposition reveals hierarchical cortical organization of the human brain

    NASA Astrophysics Data System (ADS)

    Lahav, Nir; Ksherim, Baruch; Ben-Simon, Eti; Maron-Katz, Adi; Cohen, Reuven; Havlin, Shlomo

    2016-08-01

    In recent years numerous attempts to understand the human brain were undertaken from a network point of view. A network framework takes into account the relationships between the different parts of the system and enables to examine how global and complex functions might emerge from network topology. Previous work revealed that the human brain features ‘small world’ characteristics and that cortical hubs tend to interconnect among themselves. However, in order to fully understand the topological structure of hubs, and how their profile reflect the brain’s global functional organization, one needs to go beyond the properties of a specific hub and examine the various structural layers that make up the network. To address this topic further, we applied an analysis known in statistical physics and network theory as k-shell decomposition analysis. The analysis was applied on a human cortical network, derived from MRI\\DSI data of six participants. Such analysis enables us to portray a detailed account of cortical connectivity focusing on different neighborhoods of inter-connected layers across the cortex. Our findings reveal that the human cortex is highly connected and efficient, and unlike the internet network contains no isolated nodes. The cortical network is comprised of a nucleus alongside shells of increasing connectivity that formed one connected giant component, revealing the human brain’s global functional organization. All these components were further categorized into three hierarchies in accordance with their connectivity profile, with each hierarchy reflecting different functional roles. Such a model may explain an efficient flow of information from the lowest hierarchy to the highest one, with each step enabling increased data integration. At the top, the highest hierarchy (the nucleus) serves as a global interconnected collective and demonstrates high correlation with consciousness related regions, suggesting that the nucleus might serve as a

  7. Comparative Genomic Analysis Reveals Habitat-Specific Genes and Regulatory Hubs within the Genus Novosphingobium

    PubMed Central

    Kumar, Roshan; Verma, Helianthous; Haider, Shazia; Bajaj, Abhay; Sood, Utkarsh; Ponnusamy, Kalaiarasan; Nagar, Shekhar; Shakarad, Mallikarjun N.; Negi, Ram Krishan; Singh, Yogendra; Khurana, J. P.; Gilbert, Jack A.

    2017-01-01

    ABSTRACT Species belonging to the genus Novosphingobium are found in many different habitats and have been identified as metabolically versatile. Through comparative genomic analysis, we identified habitat-specific genes and regulatory hubs that could determine habitat selection for Novosphingobium spp. Genomes from 27 Novosphingobium strains isolated from diverse habitats such as rhizosphere soil, plant surfaces, heavily contaminated soils, and marine and freshwater environments were analyzed. Genome size and coding potential were widely variable, differing significantly between habitats. Phylogenetic relationships between strains were less likely to describe functional genotype similarity than the habitat from which they were isolated. In this study, strains (19 out of 27) with a recorded habitat of isolation, and at least 3 representative strains per habitat, comprised four ecological groups—rhizosphere, contaminated soil, marine, and freshwater. Sulfur acquisition and metabolism were the only core genomic traits to differ significantly in proportion between these ecological groups; for example, alkane sulfonate (ssuABCD) assimilation was found exclusively in all of the rhizospheric isolates. When we examined osmolytic regulation in Novosphingobium spp. through ectoine biosynthesis, which was assumed to be marine habitat specific, we found that it was also present in isolates from contaminated soil, suggesting its relevance beyond the marine system. Novosphingobium strains were also found to harbor a wide variety of mono- and dioxygenases, responsible for the metabolism of several aromatic compounds, suggesting their potential to act as degraders of a variety of xenobiotic compounds. Protein-protein interaction analysis revealed β-barrel outer membrane proteins as habitat-specific hubs in each of the four habitats—freshwater (Saro_1868), marine water (PP1Y_AT17644), rhizosphere (PMI02_00367), and soil (V474_17210). These outer membrane proteins could play a

  8. Comparative Genomic Analysis Reveals Habitat-Specific Genes and Regulatory Hubs within the Genus Novosphingobium.

    PubMed

    Kumar, Roshan; Verma, Helianthous; Haider, Shazia; Bajaj, Abhay; Sood, Utkarsh; Ponnusamy, Kalaiarasan; Nagar, Shekhar; Shakarad, Mallikarjun N; Negi, Ram Krishan; Singh, Yogendra; Khurana, J P; Gilbert, Jack A; Lal, Rup

    2017-01-01

    Species belonging to the genus Novosphingobium are found in many different habitats and have been identified as metabolically versatile. Through comparative genomic analysis, we identified habitat-specific genes and regulatory hubs that could determine habitat selection for Novosphingobium spp. Genomes from 27 Novosphingobium strains isolated from diverse habitats such as rhizosphere soil, plant surfaces, heavily contaminated soils, and marine and freshwater environments were analyzed. Genome size and coding potential were widely variable, differing significantly between habitats. Phylogenetic relationships between strains were less likely to describe functional genotype similarity than the habitat from which they were isolated. In this study, strains (19 out of 27) with a recorded habitat of isolation, and at least 3 representative strains per habitat, comprised four ecological groups-rhizosphere, contaminated soil, marine, and freshwater. Sulfur acquisition and metabolism were the only core genomic traits to differ significantly in proportion between these ecological groups; for example, alkane sulfonate (ssuABCD) assimilation was found exclusively in all of the rhizospheric isolates. When we examined osmolytic regulation in Novosphingobium spp. through ectoine biosynthesis, which was assumed to be marine habitat specific, we found that it was also present in isolates from contaminated soil, suggesting its relevance beyond the marine system. Novosphingobium strains were also found to harbor a wide variety of mono- and dioxygenases, responsible for the metabolism of several aromatic compounds, suggesting their potential to act as degraders of a variety of xenobiotic compounds. Protein-protein interaction analysis revealed β-barrel outer membrane proteins as habitat-specific hubs in each of the four habitats-freshwater (Saro_1868), marine water (PP1Y_AT17644), rhizosphere (PMI02_00367), and soil (V474_17210). These outer membrane proteins could play a key role in

  9. Functional connectivity hubs of the mouse brain.

    PubMed

    Liska, Adam; Galbusera, Alberto; Schwarz, Adam J; Gozzi, Alessandro

    2015-07-15

    Recent advances in functional connectivity methods have made it possible to identify brain hubs - a set of highly connected regions serving as integrators of distributed neuronal activity. The integrative role of hub nodes makes these areas points of high vulnerability to dysfunction in brain disorders, and abnormal hub connectivity profiles have been described for several neuropsychiatric disorders. The identification of analogous functional connectivity hubs in preclinical species like the mouse may provide critical insight into the elusive biological underpinnings of these connectional alterations. To spatially locate functional connectivity hubs in the mouse brain, here we applied a fully-weighted network analysis to map whole-brain intrinsic functional connectivity (i.e., the functional connectome) at a high-resolution voxel-scale. Analysis of a large resting-state functional magnetic resonance imaging (rsfMRI) dataset revealed the presence of six distinct functional modules related to known large-scale functional partitions of the brain, including a default-mode network (DMN). Consistent with human studies, highly-connected functional hubs were identified in several sub-regions of the DMN, including the anterior and posterior cingulate and prefrontal cortices, in the thalamus, and in small foci within well-known integrative cortical structures such as the insular and temporal association cortices. According to their integrative role, the identified hubs exhibited mutual preferential interconnections. These findings highlight the presence of evolutionarily-conserved, mutually-interconnected functional hubs in the mouse brain, and may guide future investigations of the biological foundations of aberrant rsfMRI hub connectivity associated with brain pathological states.

  10. Coupling of functional connectivity and regional cerebral blood flow reveals a physiological basis for network hubs of the human brain.

    PubMed

    Liang, Xia; Zou, Qihong; He, Yong; Yang, Yihong

    2013-01-29

    Human brain functional networks contain a few densely connected hubs that play a vital role in transferring information across regions during resting and task states. However, the relationship of these functional hubs to measures of brain physiology, such as regional cerebral blood flow (rCBF), remains incompletely understood. Here, we used functional MRI data of blood-oxygenation-level-dependent and arterial-spin-labeling perfusion contrasts to investigate the relationship between functional connectivity strength (FCS) and rCBF during resting and an N-back working-memory task. During resting state, functional brain hubs with higher FCS were identified, primarily in the default-mode, insula, and visual regions. The FCS showed a striking spatial correlation with rCBF, and the correlation was stronger in the default-mode network (DMN; including medial frontal-parietal cortices) and executive control network (ECN; including lateral frontal-parietal cortices) compared with visual and sensorimotor networks. Moreover, the relationship was connection-distance dependent; i.e., rCBF correlated stronger with long-range hubs than short-range ones. It is notable that several DMN and ECN regions exhibited higher rCBF per unit connectivity strength (rCBF/FCS ratio); whereas, this index was lower in posterior visual areas. During the working-memory experiment, both FCS-rCBF coupling and rCBF/FCS ratio were modulated by task load in the ECN and/or DMN regions. Finally, task-induced changes of FCS and rCBF in the lateral-parietal lobe positively correlated with behavioral performance. Together, our results indicate a tight coupling between blood supply and brain functional topology during rest and its modulation in response to task demands, which may shed light on the physiological basis of human brain functional connectome.

  11. Cortical cartography reveals political and physical maps.

    PubMed

    Loring, David W; Gaillard, William Davis; Bookheimer, Susan Y; Meador, Kimford J; Ojemann, Jeffrey G

    2014-05-01

    Advances in functional imaging have provided noninvasive techniques to probe brain organization of multiple constructs including language and memory. Because of high overall rates of agreements with older techniques, including Wada testing and cortical stimulation mapping (CSM), some have proposed that those approaches should be largely abandoned because of their invasiveness, and replaced with noninvasive functional imaging methods. High overall agreement, however, is based largely on concordant language lateralization in series dominated by cases of typical cerebral dominance. Advocating a universal switch from Wada testing and cortical stimulation mapping to functional magnetic resonance imaging (fMRI) or magnetoencephalography (MEG) ignores the differences in specific expertise across epilepsy centers, many of which often have greater skill with one approach rather than the other, and that Wada, CSM, fMRI, and MEG protocols vary across institutions resulting in different outcomes and reliability. Specific patient characteristics also affect whether Wada or CSM might influence surgical management, making it difficult to accept broad recommendations against currently useful clinical tools. Although the development of noninvasive techniques has diminished the frequency of more invasive approaches, advocating their use to replace Wada testing and CSM across all epilepsy surgery programs without consideration of the different skills, protocols, and expertise at any given center site is ill-advised. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

  12. Multi-task connectivity reveals flexible hubs for adaptive task control.

    PubMed

    Cole, Michael W; Reynolds, Jeremy R; Power, Jonathan D; Repovs, Grega; Anticevic, Alan; Braver, Todd S

    2013-09-01

    Extensive evidence suggests that the human ability to adaptively implement a wide variety of tasks is preferentially a result of the operation of a fronto-parietal brain network (FPN). We hypothesized that this network's adaptability is made possible by flexible hubs: brain regions that rapidly update their pattern of global functional connectivity according to task demands. Using recent advances in characterizing brain network organization and dynamics, we identified mechanisms consistent with the flexible hub theory. We found that the FPN's brain-wide functional connectivity pattern shifted more than those of other networks across a variety of task states and that these connectivity patterns could be used to identify the current task. Furthermore, these patterns were consistent across practiced and novel tasks, suggesting that reuse of flexible hub connectivity patterns facilitates adaptive (novel) task performance. Together, these findings support a central role for fronto-parietal flexible hubs in cognitive control and adaptive implementation of task demands.

  13. Dysregulated signaling hubs of liver lipid metabolism reveal hepatocellular carcinoma pathogenesis

    PubMed Central

    Lee, Sunjae; Mardinoglu, Adil; Zhang, Cheng; Lee, Doheon; Nielsen, Jens

    2016-01-01

    Hepatocellular carcinoma (HCC) has a high mortality rate and early detection of HCC is crucial for the application of effective treatment strategies. HCC is typically caused by either viral hepatitis infection or by fatty liver disease. To diagnose and treat HCC it is necessary to elucidate the underlying molecular mechanisms. As a major cause for development of HCC is fatty liver disease, we here investigated anomalies in regulation of lipid metabolism in the liver. We applied a tailored network-based approach to identify signaling hubs associated with regulation of this part of metabolism. Using transcriptomics data of HCC patients, we identified significant dysregulated expressions of lipid-regulated genes, across many different lipid metabolic pathways. Our findings, however, show that viral hepatitis causes HCC by a distinct mechanism, less likely involving lipid anomalies. Based on our analysis we suggest signaling hub genes governing overall catabolic or anabolic pathways, as novel drug targets for treatment of HCC that involves lipid anomalies. PMID:27216817

  14. Multi-task connectivity reveals flexible hubs for adaptive task control

    PubMed Central

    Cole, Michael W.; Reynolds, Jeremy R.; Power, Jonathan D.; Repovs, Grega; Anticevic, Alan; Braver, Todd S.

    2013-01-01

    Extensive evidence suggests the human ability to adaptively implement a wide variety of tasks is preferentially due to the operation of a fronto-parietal brain network. We hypothesized that this network’s adaptability is made possible by ‘flexible hubs’ – brain regions that rapidly update their pattern of global functional connectivity according to task demands. We utilized recent advances in characterizing brain network organization and dynamics to identify mechanisms consistent with the flexible hub theory. We found that the fronto-parietal network’s brain-wide functional connectivity pattern shifted more than other networks’ across a variety of task states, and that these connectivity patterns could be used to identify the current task. Further, these patterns were consistent across practiced and novel tasks, suggesting reuse of flexible hub connectivity patterns facilitates adaptive (novel) task performance. Together, these findings support a central role for fronto-parietal flexible hubs in cognitive control and adaptive implementation of task demands generally. PMID:23892552

  15. Revealing long-range interconnected hubs in human chromatin interaction data using graph theory.

    PubMed

    Boulos, R E; Arneodo, A; Jensen, P; Audit, B

    2013-09-13

    We use graph theory to analyze chromatin interaction (Hi-C) data in the human genome. We show that a key functional feature of the genome--"master" replication origins--corresponds to DNA loci of maximal network centrality. These loci form a set of interconnected hubs both within chromosomes and between different chromosomes. Our results open the way to a fruitful use of graph theory concepts to decipher DNA structural organization in relation to genome functions such as replication and transcription. This quantitative information should prove useful to discriminate between possible polymer models of nuclear organization.

  16. Revealing Long-Range Interconnected Hubs in Human Chromatin Interaction Data Using Graph Theory

    NASA Astrophysics Data System (ADS)

    Boulos, R. E.; Arneodo, A.; Jensen, P.; Audit, B.

    2013-09-01

    We use graph theory to analyze chromatin interaction (Hi-C) data in the human genome. We show that a key functional feature of the genome—“master” replication origins—corresponds to DNA loci of maximal network centrality. These loci form a set of interconnected hubs both within chromosomes and between different chromosomes. Our results open the way to a fruitful use of graph theory concepts to decipher DNA structural organization in relation to genome functions such as replication and transcription. This quantitative information should prove useful to discriminate between possible polymer models of nuclear organization.

  17. Somatosensory cortical plasticity in adult humans revealed by magnetoencephalography.

    PubMed Central

    Mogilner, A; Grossman, J A; Ribary, U; Joliot, M; Volkmann, J; Rapaport, D; Beasley, R W; Llinás, R R

    1993-01-01

    Microelectrode recordings in adult mammals have clearly demonstrated that somatosensory cortical maps reorganize following peripheral nerve injuries and functional modifications; however, such reorganization has never been directly demonstrated in humans. Using magnetoencephalography, we have been able to demonstrate the somatotopic organization of the hand area in normal humans with high spatial precision. Somatosensory cortical plasticity was detected in two adults who were studied before and after surgical separation of webbed fingers (syndactyly). The presurgical maps displayed shrunken and nonsomatotopic hand representations. Within weeks following surgery, cortical reorganization occurring over distances of 3-9 mm was evident, correlating with the new functional status of their separated digits. In contrast, no modification of the somatosensory map was observed months following transfer of a neurovascular skin island flap for sensory reconstruction of the thumb in two subjects in whom sensory transfer failed to occur. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8386377

  18. Spatial Heterogeneity of Cortical Excitability in Migraine Revealed by Multi-Frequency Neuromagnetic Signals

    PubMed Central

    Xiang, Jing; Leiken, Kimberly; Degrauw, Xinyao; Kay, Benjamin; Fujiwara, Hisako; Rose, Douglas F.; Allen, Janelle R.; Kacperski, Joanne E.; O’Brien, Hope L.; Kabbouche, Marielle A.; Powers, Scott W.; Hershey, Andrew D.

    2016-01-01

    To investigate the spatial heterogeneity of cortical excitability in adolescents with migraine, magnetoencephalography (MEG) recordings at a sampling rate of 6000 Hz were obtained from 35 adolescents with an acute migraine and 35 age- and gender-matched healthy controls during an auditory-motor task. Neuromagnetic activation from low- to high-frequency ranges (5–1,000 Hz) was measured at both sensor and source levels. The heterogeneity of cortical excitability was quantified within each functional modality (auditory vs. motor) and hemispherical lateralization. MEG data showed that high-frequency, not low-frequency neuromagnetic signals, revealed heterogeneous cortical activation in migraine subjects as compared with controls (p < 0.001). The alteration of the heterogeneity of cortical excitability in migraine was independent of age and gender. The degree of the neuromagnetic heterogeneity of cortical activation was significantly correlated with headache frequency (r=0.71, p < 0.005). The alteration of cortical excitability in migraine is spatially heterogeneous and frequency dependent, which has not previously been reported. The finding may be critical for developing spatially targeted therapeutic strategies for normalizing cortical excitability with the purpose of reducing headache attacks. Perspective This article presents a new approach to quantitatively measuring the spatial heterogeneity of cortical excitability in adolescents with migraine using MEG signals in a frequency range of 5–1000 Hz. The characteristics of the location and degree of cortical excitability may be critical for spatially targeted treatment for migraine. PMID:26970516

  19. The development of hub architecture in the human functional brain network.

    PubMed

    Hwang, Kai; Hallquist, Michael N; Luna, Beatriz

    2013-10-01

    Functional hubs are brain regions that play a crucial role in facilitating communication among parallel, distributed brain networks. The developmental emergence and stability of hubs, however, is not well understood. The current study used measures of network topology drawn from graph theory to investigate the development of functional hubs in 99 participants, 10-20 years of age. We found that hub architecture was evident in late childhood and was stable from adolescence to early adulthood. Connectivity between hub and non-hub ("spoke") regions, however, changed with development. From childhood to adolescence, the strength of connections between frontal hubs and cortical and subcortical spoke regions increased. From adolescence to adulthood, hub-spoke connections with frontal hubs were stable, whereas connectivity between cerebellar hubs and cortical spoke regions increased. Our findings suggest that a developmentally stable functional hub architecture provides the foundation of information flow in the brain, whereas connections between hubs and spokes continue to develop, possibly supporting mature cognitive function.

  20. Electromyographic activation reveals cortical and sub-cortical dissociation during emergence from general anesthesia.

    PubMed

    Hight, Darren F; Voss, Logan J; García, Paul S; Sleigh, Jamie W

    2016-07-21

    During emergence from anesthesia patients regain their muscle tone (EMG). In a typical population of surgical patients the actual volatile gas anesthetic concentrations in the brain (CeMAC) at which EMG activation occurs remains unknown, as is whether EMG activation at higher CeMACs is correlated with subsequent severe pain, or with cortical activation. Electroencephalographic (EEG) and EMG activity was recorded from the forehead of 273 patients emerging from general anesthesia following surgery. We determined CeMAC at time of EMG activation and at return of consciousness. Pain was assessed immediately after return of consciousness using an 11 point numerical rating scale. The onset of EMG activation during emergence was associated with neither discernible muscle movement nor with the presence of exogenous stimulation in half the patients. EMG activation could be modelled as two distinct processes; termed high- and low-CeMAC (occurring higher or lower than 0.07 CeMAC). Low-CeMAC activation was typically associated with simultaneous EMG activation and consciousness, and the presence of a laryngeal mask. In contrast, high-CeMAC EMG activation occurred independently of return of consciousness, and was not associated with severe post-operative pain, but was more common in the presence of an endotracheal tube. Patients emerging from general anesthesia with an endotracheal tube in place are more likely to have an EMG activation at higher CeMAC concentrations. These activations are not associated with subsequent high-pain, nor with cortical arousal, as evidenced by continuing delta waves in the EEG. Conversely, patients emerging from general anesthesia with a laryngeal mask demonstrate marked neural inertia-EMG activation occurs at a low CeMAC, and is closely temporally associated with return of consciousness.

  1. Integration of transcriptomic and metabolic data reveals hub transcription factors involved in drought stress response in sunflower (Helianthus annuus L.).

    PubMed

    Moschen, Sebastián; Di Rienzo, Julio A; Higgins, Janet; Tohge, Takayuki; Watanabe, Mutsumi; González, Sergio; Rivarola, Máximo; García-García, Francisco; Dopazo, Joaquin; Hopp, H Esteban; Hoefgen, Rainer; Fernie, Alisdair R; Paniego, Norma; Fernández, Paula; Heinz, Ruth A

    2017-07-01

    By integration of transcriptional and metabolic profiles we identified pathways and hubs transcription factors regulated during drought conditions in sunflower, useful for applications in molecular and/or biotechnological breeding. Drought is one of the most important environmental stresses that effects crop productivity in many agricultural regions. Sunflower is tolerant to drought conditions but the mechanisms involved in this tolerance remain unclear at the molecular level. The aim of this study was to characterize and integrate transcriptional and metabolic pathways related to drought stress in sunflower plants, by using a system biology approach. Our results showed a delay in plant senescence with an increase in the expression level of photosynthesis related genes as well as higher levels of sugars, osmoprotectant amino acids and ionic nutrients under drought conditions. In addition, we identified transcription factors that were upregulated during drought conditions and that may act as hubs in the transcriptional network. Many of these transcription factors belong to families implicated in the drought response in model species. The integration of transcriptomic and metabolomic data in this study, together with physiological measurements, has improved our understanding of the biological responses during droughts and contributes to elucidate the molecular mechanisms involved under this environmental condition. These findings will provide useful biotechnological tools to improve stress tolerance while maintaining crop yield under restricted water availability.

  2. Competing Sound Sources Reveal Spatial Effects in Cortical Processing

    PubMed Central

    Maddox, Ross K.; Billimoria, Cyrus P.; Perrone, Ben P.; Shinn-Cunningham, Barbara G.; Sen, Kamal

    2012-01-01

    Why is spatial tuning in auditory cortex weak, even though location is important to object recognition in natural settings? This question continues to vex neuroscientists focused on linking physiological results to auditory perception. Here we show that the spatial locations of simultaneous, competing sound sources dramatically influence how well neural spike trains recorded from the zebra finch field L (an analog of mammalian primary auditory cortex) encode source identity. We find that the location of a birdsong played in quiet has little effect on the fidelity of the neural encoding of the song. However, when the song is presented along with a masker, spatial effects are pronounced. For each spatial configuration, a subset of neurons encodes song identity more robustly than others. As a result, competing sources from different locations dominate responses of different neural subpopulations, helping to separate neural responses into independent representations. These results help elucidate how cortical processing exploits spatial information to provide a substrate for selective spatial auditory attention. PMID:22563301

  3. Altered brain structural networks in attention deficit/hyperactivity disorder children revealed by cortical thickness.

    PubMed

    Liu, Tian; Chen, Yanni; Li, Chenxi; Li, Youjun; Wang, Jue

    2017-01-18

    This study investigated the cortical thickness and topological features of human brain anatomical networks related to attention deficit/hyperactivity disorder. Data were collected from 40 attention deficit/hyperactivity disorder children and 40 normal control children. Interregional correlation matrices were established by calculating the correlations of cortical thickness between all pairs of cortical regions (68 regions) of the whole brain. Further thresholds were applied to create binary matrices to construct a series of undirected and unweighted graphs, and global, local, and nodal efficiencies were computed as a function of the network cost. These experimental results revealed abnormal cortical thickness and correlations in attention deficit/hyperactivity disorder, and showed that the brain structural networks of attention deficit/hyperactivity disorder subjects had inefficient small-world topological features. Furthermore, their topological properties were altered abnormally. In particular, decreased global efficiency combined with increased local efficiency in attention deficit/hyperactivity disorder children led to a disorder-related shift of the network topological structure toward regular networks. In addition, nodal efficiency, cortical thickness, and correlation analyses revealed that several brain regions were altered in attention deficit/hyperactivity disorder patients. These findings are in accordance with a hypothesis of dysfunctional integration and segregation of the brain in patients with attention deficit/hyperactivity disorder and provide further evidence of brain dysfunction in attention deficit/hyperactivity disorder patients by observing cortical thickness on magnetic resonance imaging.

  4. Functional Connectivity Hubs and Networks in the Awake Marmoset Brain

    PubMed Central

    Belcher, Annabelle M.; Yen, Cecil Chern-Chyi; Notardonato, Lucia; Ross, Thomas J.; Volkow, Nora D.; Yang, Yihong; Stein, Elliot A.; Silva, Afonso C.; Tomasi, Dardo

    2016-01-01

    In combination with advances in analytical methods, resting-state fMRI is allowing unprecedented access to a better understanding of the network organization of the brain. Increasing evidence suggests that this architecture may incorporate highly functionally connected nodes, or “hubs”, and we have recently proposed local functional connectivity density (lFCD) mapping to identify highly-connected nodes in the human brain. Here, we imaged awake nonhuman primates to test whether, like the human brain, the marmoset brain contains FC hubs. Ten adult common marmosets (Callithrix jacchus) were acclimated to mild, comfortable restraint using individualized helmets. Following restraint training, resting BOLD data were acquired during eight consecutive 10 min scans for each subject. lFCD revealed prominent cortical and subcortical hubs of connectivity across the marmoset brain; specifically, in primary and secondary visual cortices (V1/V2), higher-order visual association areas (A19M/V6[DM]), posterior parietal and posterior cingulate areas (PGM and A23b/A31), thalamus, dorsal and ventral striatal areas (caudate, putamen, lateral septal nucleus, and anterior cingulate cortex (A24a). lFCD hubs were highly connected to widespread areas of the brain, and further revealed significant network-network interactions. These data provide a baseline platform for future investigations in a nonhuman primate model of the brain’s network topology. PMID:26973476

  5. Disclosure of a structural milieu for the proximity ligation reveals the elusive nature of an active chromatin hub

    PubMed Central

    Gavrilov, Alexey A.; Gushchanskaya, Ekaterina S.; Strelkova, Olga; Zhironkina, Oksana; Kireev, Igor I.; Iarovaia, Olga V.; Razin, Sergey V.

    2013-01-01

    The current progress in the study of the spatial organization of interphase chromosomes became possible owing to the development of the chromosome conformation capture (3C) protocol. The crucial step of this protocol is the proximity ligation—preferential ligation of DNA fragments assumed to be joined within nuclei by protein bridges and solubilized as a common complex after formaldehyde cross-linking and DNA cleavage. Here, we show that a substantial, and in some cases the major, part of DNA is not solubilized from cross-linked nuclei treated with restriction endonuclease(s) and sodium dodecyl sulphate and that this treatment neither causes lysis of the nucleus nor drastically affects its internal organization. Analysis of the ligation frequencies of the mouse β-globin gene domain DNA fragments demonstrated that the previously reported 3C signals were generated predominantly, if not exclusively, in the insoluble portion of the 3C material. The proximity ligation thus occurs within the cross-linked chromatin cage in non-lysed nuclei. The finding does not compromise the 3C protocol but allows the consideration of an active chromatin hub as a folded chromatin domain or a nuclear compartment rather than a rigid complex of regulatory elements. PMID:23396278

  6. Disclosure of a structural milieu for the proximity ligation reveals the elusive nature of an active chromatin hub.

    PubMed

    Gavrilov, Alexey A; Gushchanskaya, Ekaterina S; Strelkova, Olga; Zhironkina, Oksana; Kireev, Igor I; Iarovaia, Olga V; Razin, Sergey V

    2013-04-01

    The current progress in the study of the spatial organization of interphase chromosomes became possible owing to the development of the chromosome conformation capture (3C) protocol. The crucial step of this protocol is the proximity ligation-preferential ligation of DNA fragments assumed to be joined within nuclei by protein bridges and solubilized as a common complex after formaldehyde cross-linking and DNA cleavage. Here, we show that a substantial, and in some cases the major, part of DNA is not solubilized from cross-linked nuclei treated with restriction endonuclease(s) and sodium dodecyl sulphate and that this treatment neither causes lysis of the nucleus nor drastically affects its internal organization. Analysis of the ligation frequencies of the mouse β-globin gene domain DNA fragments demonstrated that the previously reported 3C signals were generated predominantly, if not exclusively, in the insoluble portion of the 3C material. The proximity ligation thus occurs within the cross-linked chromatin cage in non-lysed nuclei. The finding does not compromise the 3C protocol but allows the consideration of an active chromatin hub as a folded chromatin domain or a nuclear compartment rather than a rigid complex of regulatory elements.

  7. Synaptic Interactome Mining Reveals p140Cap as a New Hub for PSD Proteins Involved in Psychiatric and Neurological Disorders

    PubMed Central

    Alfieri, Annalisa; Sorokina, Oksana; Adrait, Annie; Angelini, Costanza; Russo, Isabella; Morellato, Alessandro; Matteoli, Michela; Menna, Elisabetta; Boeri Erba, Elisabetta; McLean, Colin; Armstrong, J. Douglas; Ala, Ugo; Buxbaum, Joseph D.; Brusco, Alfredo; Couté, Yohann; De Rubeis, Silvia; Turco, Emilia; Defilippi, Paola

    2017-01-01

    Altered synaptic function has been associated with neurological and psychiatric conditions including intellectual disability, schizophrenia and autism spectrum disorder (ASD). Amongst the recently discovered synaptic proteins is p140Cap, an adaptor that localizes at dendritic spines and regulates their maturation and physiology. We recently showed that p140Cap knockout mice have cognitive deficits, impaired long-term potentiation (LTP) and long-term depression (LTD), and immature, filopodia-like dendritic spines. Only a few p140Cap interacting proteins have been identified in the brain and the molecular complexes and pathways underlying p140Cap synaptic function are largely unknown. Here, we isolated and characterized the p140Cap synaptic interactome by co-immunoprecipitation from crude mouse synaptosomes, followed by mass spectrometry-based proteomics. We identified 351 p140Cap interactors and found that they cluster to sub complexes mostly located in the postsynaptic density (PSD). p140Cap interactors converge on key synaptic processes, including transmission across chemical synapses, actin cytoskeleton remodeling and cell-cell junction organization. Gene co-expression data further support convergent functions: the p140Cap interactors are tightly co-expressed with each other and with p140Cap. Importantly, the p140Cap interactome and its co-expression network show strong enrichment in genes associated with schizophrenia, autism, bipolar disorder, intellectual disability and epilepsy, supporting synaptic dysfunction as a shared biological feature in brain diseases. Overall, our data provide novel insights into the molecular organization of the synapse and indicate that p140Cap acts as a hub for postsynaptic complexes relevant to psychiatric and neurological disorders. PMID:28713243

  8. Network Receptive Field Modeling Reveals Extensive Integration and Multi-feature Selectivity in Auditory Cortical Neurons.

    PubMed

    Harper, Nicol S; Schoppe, Oliver; Willmore, Ben D B; Cui, Zhanfeng; Schnupp, Jan W H; King, Andrew J

    2016-11-01

    Cortical sensory neurons are commonly characterized using the receptive field, the linear dependence of their response on the stimulus. In primary auditory cortex neurons can be characterized by their spectrotemporal receptive fields, the spectral and temporal features of a sound that linearly drive a neuron. However, receptive fields do not capture the fact that the response of a cortical neuron results from the complex nonlinear network in which it is embedded. By fitting a nonlinear feedforward network model (a network receptive field) to cortical responses to natural sounds, we reveal that primary auditory cortical neurons are sensitive over a substantially larger spectrotemporal domain than is seen in their standard spectrotemporal receptive fields. Furthermore, the network receptive field, a parsimonious network consisting of 1-7 sub-receptive fields that interact nonlinearly, consistently better predicts neural responses to auditory stimuli than the standard receptive fields. The network receptive field reveals separate excitatory and inhibitory sub-fields with different nonlinear properties, and interaction of the sub-fields gives rise to important operations such as gain control and conjunctive feature detection. The conjunctive effects, where neurons respond only if several specific features are present together, enable increased selectivity for particular complex spectrotemporal structures, and may constitute an important stage in sound recognition. In conclusion, we demonstrate that fitting auditory cortical neural responses with feedforward network models expands on simple linear receptive field models in a manner that yields substantially improved predictive power and reveals key nonlinear aspects of cortical processing, while remaining easy to interpret in a physiological context.

  9. Network Receptive Field Modeling Reveals Extensive Integration and Multi-feature Selectivity in Auditory Cortical Neurons

    PubMed Central

    Willmore, Ben D. B.; Cui, Zhanfeng; Schnupp, Jan W. H.; King, Andrew J.

    2016-01-01

    Cortical sensory neurons are commonly characterized using the receptive field, the linear dependence of their response on the stimulus. In primary auditory cortex neurons can be characterized by their spectrotemporal receptive fields, the spectral and temporal features of a sound that linearly drive a neuron. However, receptive fields do not capture the fact that the response of a cortical neuron results from the complex nonlinear network in which it is embedded. By fitting a nonlinear feedforward network model (a network receptive field) to cortical responses to natural sounds, we reveal that primary auditory cortical neurons are sensitive over a substantially larger spectrotemporal domain than is seen in their standard spectrotemporal receptive fields. Furthermore, the network receptive field, a parsimonious network consisting of 1–7 sub-receptive fields that interact nonlinearly, consistently better predicts neural responses to auditory stimuli than the standard receptive fields. The network receptive field reveals separate excitatory and inhibitory sub-fields with different nonlinear properties, and interaction of the sub-fields gives rise to important operations such as gain control and conjunctive feature detection. The conjunctive effects, where neurons respond only if several specific features are present together, enable increased selectivity for particular complex spectrotemporal structures, and may constitute an important stage in sound recognition. In conclusion, we demonstrate that fitting auditory cortical neural responses with feedforward network models expands on simple linear receptive field models in a manner that yields substantially improved predictive power and reveals key nonlinear aspects of cortical processing, while remaining easy to interpret in a physiological context. PMID:27835647

  10. P-hub protection models for survivable hub network design

    NASA Astrophysics Data System (ADS)

    Kim, Hyun

    2012-10-01

    The design of survivable networks has been a significant issue in network-based infrastructure in transportation, electric power systems, and telecommunications. In telecommunications networks, hubs and backbones are the most critical assets to be protected from any network failure because many network flows use these facilities, resulting in an intensive concentration of flows at these facilities. This paper addresses a series of new hub and spoke network models as survivable network designs, which are termed p- hub protection models (PHPRO). The PHPRO aim to build networks that maximize the total potential interacting traffic over a set of origin-destination nodes based on different routing assumptions, including multiple assignments and back-up hub routes with distance restrictions. Empirical analyses are presented using telecommunication networks in the United States, and the vulnerabilities of networks based on possible disruption scenarios are examined. The results reveal that PROBA, the model with a back-up routing scheme, considerably enhances the network resilience and even the network performance, indicating that the model is a candidate for a strong survivable hub network design. An extension, PROBA-D, also shows that applying a distance restriction can be strategically used for designing back-up hub routes if a network can trade off between network performance and network cost, which results from the reduced length of back-up routings.

  11. Holistic atlases of functional networks and interactions reveal reciprocal organizational architecture of cortical function.

    PubMed

    Lv, Jinglei; Jiang, Xi; Li, Xiang; Zhu, Dajiang; Zhang, Shu; Zhao, Shijie; Chen, Hanbo; Zhang, Tuo; Hu, Xintao; Han, Junwei; Ye, Jieping; Guo, Lei; Liu, Tianming

    2015-04-01

    For decades, it has been largely unknown to what extent multiple functional networks spatially overlap/interact with each other and jointly realize the total cortical function. Here, by developing novel sparse representation of whole-brain fMRI signals and by using the recently publicly released large-scale Human Connectome Project high-quality fMRI data, we show that a number of reproducible and robust functional networks, including both task-evoked and resting state networks, are simultaneously distributed in distant neuroanatomic areas and substantially spatially overlapping with each other, thus forming an initial collection of holistic atlases of functional networks and interactions (HAFNIs). More interestingly, the HAFNIs revealed two distinct patterns of highly overlapped regions and highly specialized regions and exhibited that these two patterns of areas are reciprocally localized, revealing a novel organizational principle of cortical function.

  12. Spatiotemporal dynamics of word retrieval in speech production revealed by cortical high-frequency band activity.

    PubMed

    Riès, Stephanie K; Dhillon, Rummit K; Clarke, Alex; King-Stephens, David; Laxer, Kenneth D; Weber, Peter B; Kuperman, Rachel A; Auguste, Kurtis I; Brunner, Peter; Schalk, Gerwin; Lin, Jack J; Parvizi, Josef; Crone, Nathan E; Dronkers, Nina F; Knight, Robert T

    2017-06-06

    Word retrieval is core to language production and relies on complementary processes: the rapid activation of lexical and conceptual representations and word selection, which chooses the correct word among semantically related competitors. Lexical and conceptual activation is measured by semantic priming. In contrast, word selection is indexed by semantic interference and is hampered in semantically homogeneous (HOM) contexts. We examined the spatiotemporal dynamics of these complementary processes in a picture naming task with blocks of semantically heterogeneous (HET) or HOM stimuli. We used electrocorticography data obtained from frontal and temporal cortices, permitting detailed spatiotemporal analysis of word retrieval processes. A semantic interference effect was observed with naming latencies longer in HOM versus HET blocks. Cortical response strength as indexed by high-frequency band (HFB) activity (70-150 Hz) amplitude revealed effects linked to lexical-semantic activation and word selection observed in widespread regions of the cortical mantle. Depending on the subsecond timing and cortical region, HFB indexed semantic interference (i.e., more activity in HOM than HET blocks) or semantic priming effects (i.e., more activity in HET than HOM blocks). These effects overlapped in time and space in the left posterior inferior temporal gyrus and the left prefrontal cortex. The data do not support a modular view of word retrieval in speech production but rather support substantial overlap of lexical-semantic activation and word selection mechanisms in the brain.

  13. Neuroperceptual differences in consonant and vowel discrimination: as revealed by direct cortical electrical interference.

    PubMed

    Boatman, D; Hall, C; Goldstein, M H; Lesser, R; Gordon, B

    1997-03-01

    The effects of direct cortical electrical interference on consonant and vowel discrimination were investigated in five patients with implanted subdural electrode arrays. Without electrical interference, patients performance discriminating consonants and vowels was intact. With electrical interference, consonant discrimination was impaired at one electrode site in each patient on the superior temporal gyrus of the lateral left perisylvian cortex. Conversely, vowel and tone discrimination remained relatively intact when tested with electrical interference at the same site. Analysis of patients' consonant discrimination errors revealed that neither differences in acoustic temporal structure nor syllable position fully account for the consonant-vowel perceptual dissociations elicited. Our data suggest that at the cortical level consonant and vowel perception are intrinsically distinct perceptual phenomena. The selective impairment of consonant, but not vowel, discrimination further suggests that consonant and vowel perception are distinguished by differences in relative dependence on the functional--perhaps integrative--resources of the left lateral superior temporal gyrus.

  14. Functional Dissection of the NuA4 Histone Acetyltransferase Reveals Its Role as a Genetic Hub and that Eaf1 Is Essential for Complex Integrity▿

    PubMed Central

    Mitchell, Leslie; Lambert, Jean-Philippe; Gerdes, Maria; Al-Madhoun, Ashraf S.; Skerjanc, Ilona S.; Figeys, Daniel; Baetz, Kristin

    2008-01-01

    The Saccharomyces cerevisiae NuA4 histone acetyltransferase complex catalyzes the acetylation of histone H4 and the histone variant Htz1 to regulate key cellular events, including transcription, DNA repair, and faithful chromosome segregation. To further investigate the cellular processes impacted by NuA4, we exploited the nonessential subunits of the complex to build an extensive NuA4 genetic-interaction network map. The map reveals that NuA4 is a genetic hub whose function buffers a diverse range of cellular processes, many not previously linked to the complex, including Golgi complex-to-vacuole vesicle-mediated transport. Further, we probe the role that nonessential subunits play in NuA4 complex integrity. We find that most nonessential subunits have little impact on NuA4 complex integrity and display between 12 and 42 genetic interactions. In contrast, the deletion of EAF1 causes the collapse of the NuA4 complex and displays 148 genetic interactions. Our study indicates that Eaf1 plays a crucial function in NuA4 complex integrity. Further, we determine that Eaf5 and Eaf7 form a subcomplex, which reflects their similar genetic interaction profiles and phenotypes. Our integrative study demonstrates that genetic interaction maps are valuable in dissecting complex structure and provides insight into why the human NuA4 complex, Tip60, has been associated with a diverse range of pathologies. PMID:18212056

  15. Systems pharmacology of mifepristone (RU486) reveals its 47 hub targets and network: Comprehensive analysis and pharmacological focus on FAK-Src-Paxillin complex

    PubMed Central

    Yu, Suhong; Yang, Xingtian; Zhu, Yewei; Xie, Fangwei; Lu, Yusheng; Yu, Ting; Yan, Cuicui; Shao, Jingwei; Gao, Yu; Mo, Fan; Cai, Guoneng; Sinko, Patrick J.; Jia, Lee

    2015-01-01

    Mifepristone (RU486), a synthetic steroid compound used as an abortifacient drug, has received considerable attention to its anticancer activity recently. To explore the possibility of using mifepristone as a cancer metastasis chemopreventive, we performed a systems pharmacology analysis of mifepristone-related molecules in the present study. Data were collected by using Natural Language Processing (NLP) and 513 mifepristone-related genes were dug out and classified functionally using a gene ontology (GO) hierarchy, followed by KEGG pathway enrichment analysis. Potential signal pathways and targets involved in cancer were obtained by integrative network analysis. Total thirty-three proteins were involved in focal adhesion-the key signaling pathway associated with cancer metastasis. Molecular and cellular assays further demonstrated that mifepristone had the ability to prevent breast cancer cells from migration and interfere with their adhesion to endothelial cells. Moreover, mifepristone inhibited the expression of focal adhesion kinase (FAK), paxillin, and the formation of FAK/Src/Paxillin complex, which are correlated with cell adhesion and migration. This study set a good example to identify chemotherapeutic potential seamlessly from systems pharmacology to cellular pharmacology, and the revealed hub genes may be the promising targets for cancer metastasis chemoprevention. PMID:25597938

  16. Systems pharmacology of mifepristone (RU486) reveals its 47 hub targets and network: comprehensive analysis and pharmacological focus on FAK-Src-Paxillin complex.

    PubMed

    Yu, Suhong; Yang, Xingtian; Zhu, Yewei; Xie, Fangwei; Lu, Yusheng; Yu, Ting; Yan, Cuicui; Shao, Jingwei; Gao, Yu; Mo, Fan; Cai, Guoneng; Sinko, Patrick J; Jia, Lee

    2015-01-19

    Mifepristone (RU486), a synthetic steroid compound used as an abortifacient drug, has received considerable attention to its anticancer activity recently. To explore the possibility of using mifepristone as a cancer metastasis chemopreventive, we performed a systems pharmacology analysis of mifepristone-related molecules in the present study. Data were collected by using Natural Language Processing (NLP) and 513 mifepristone-related genes were dug out and classified functionally using a gene ontology (GO) hierarchy, followed by KEGG pathway enrichment analysis. Potential signal pathways and targets involved in cancer were obtained by integrative network analysis. Total thirty-three proteins were involved in focal adhesion-the key signaling pathway associated with cancer metastasis. Molecular and cellular assays further demonstrated that mifepristone had the ability to prevent breast cancer cells from migration and interfere with their adhesion to endothelial cells. Moreover, mifepristone inhibited the expression of focal adhesion kinase (FAK), paxillin, and the formation of FAK/Src/Paxillin complex, which are correlated with cell adhesion and migration. This study set a good example to identify chemotherapeutic potential seamlessly from systems pharmacology to cellular pharmacology, and the revealed hub genes may be the promising targets for cancer metastasis chemoprevention.

  17. Convergence of prefrontal and parietal anatomical projections in a connectional hub in the striatum.

    PubMed

    Choi, Eun Young; Tanimura, Yoko; Vage, Priti R; Yates, Ellen H; Haber, Suzanne N

    2017-02-01

    Visual attentional bias forms for rewarding and punishing stimuli in the environment. While this attentional bias is adaptive in healthy situations, it is maladaptive in disorders such as drug addiction or PTSD. In both these disorders, the ability to exert control over this attentional bias is associated with drug abstinence rates or reduced PTSD symptoms, indicating the interaction of visual attention, cognitive control, and stimulus association. The inferior parietal lobule (IPL) is central to attention, while the prefrontal cortex (PFC) is critical for reward, cognitive control, and attention. Importantly, regions of the IPL and PFC commonly project to the rostral dorsal caudate (rdCaud) of the striatum. We propose an anatomical network architecture in which IPL projections converge with PFC projections in a connectional hub in the rdCaud, providing an anatomical substrate for the interaction of these projections and their competitive influence on striatal processing. To investigate this, we mapped the dense projections from the caudal IPL and prefrontal (dlPFC, vlPFC, OFC, dACC, and dmPFC) regions that project to the medial rdCaud with anatomical tract-tracing tracer injections in monkeys. These inputs converge in a precise site in the medial rdCaud, rostral to the anterior commissure. Small retrograde tracer injections confirmed these inputs to the medial rdCaud and showed that a proximal ventral striatal location has a very different pattern of cortical inputs. We next used human resting-state functional connectivity MRI (fcMRI) to examine whether a striatal hub exists in the human medial rdCaud. Seed regions in the human medial rdCaud revealed cortical correlation maps similar to the monkey retrograde injection results. A subsequent analysis of these correlated cortical regions showed that their peak correlation within the striatum is in the medial rdCaud, indicating that this is a connectional hub. In contrast, this peak striatal correlation was not found

  18. Stator hub treatment study

    NASA Technical Reports Server (NTRS)

    Wisler, D. C.; Hilvers, D. E.

    1974-01-01

    The results of an experimental research program to investigate the potential of improving compressor stall margin by the application of hub treatment are presented. Extensive tuft probing showed that the two-stage, 0.5 radius ratio compressor selected for the test was indeed hub critical. Circumferential groove and baffled wide blade angle slot hub treatments under the stators were tested. Performance measurements were made with total and static pressure probes, wall static pressure taps, flow angle measuring instrumentation and hot film anemometers. Stator hub treatment was not found to be effective in improving compressor stall margin by delaying the point of onset of rotating stall or in modifying compressor performance for any of the configurations tested. Extensive regions of separated flow were observed on the suction surface of the stators near the hub. However, the treatment did not delay the point where flow separation in the stator hub region becomes apparent.

  19. Transcriptome sequencing revealed significant alteration of cortical promoter usage and splicing in schizophrenia.

    PubMed

    Wu, Jing Qin; Wang, Xi; Beveridge, Natalie J; Tooney, Paul A; Scott, Rodney J; Carr, Vaughan J; Cairns, Murray J

    2012-01-01

    While hybridization based analysis of the cortical transcriptome has provided important insight into the neuropathology of schizophrenia, it represents a restricted view of disease-associated gene activity based on predetermined probes. By contrast, sequencing technology can provide un-biased analysis of transcription at nucleotide resolution. Here we use this approach to investigate schizophrenia-associated cortical gene expression. The data was generated from 76 bp reads of RNA-Seq, aligned to the reference genome and assembled into transcripts for quantification of exons, splice variants and alternative promoters in postmortem superior temporal gyrus (STG/BA22) from 9 male subjects with schizophrenia and 9 matched non-psychiatric controls. Differentially expressed genes were then subjected to further sequence and functional group analysis. The output, amounting to more than 38 Gb of sequence, revealed significant alteration of gene expression including many previously shown to be associated with schizophrenia. Gene ontology enrichment analysis followed by functional map construction identified three functional clusters highly relevant to schizophrenia including neurotransmission related functions, synaptic vesicle trafficking, and neural development. Significantly, more than 2000 genes displayed schizophrenia-associated alternative promoter usage and more than 1000 genes showed differential splicing (FDR<0.05). Both types of transcriptional isoforms were exemplified by reads aligned to the neurodevelopmentally significant doublecortin-like kinase 1 (DCLK1) gene. This study provided the first deep and un-biased analysis of schizophrenia-associated transcriptional diversity within the STG, and revealed variants with important implications for the complex pathophysiology of schizophrenia.

  20. Mapping Human Cortical Areas in vivo Based on Myelin Content as Revealed by T1- and T2-weighted MRI

    PubMed Central

    Glasser, Matthew F.; Van Essen, David C.

    2011-01-01

    Non-invasively mapping the layout of cortical areas in humans is a continuing challenge for neuroscience. We present a new method of mapping cortical areas based on myelin content as revealed by T1-weighted (T1w) and T2-weighted (T2w) MRI. The method is generalizable across different 3T scanners and pulse sequences. We use the ratio of T1w/T2w image intensities to eliminate the MR-related image intensity bias and enhance the contrast to noise ratio for myelin. Data from each subject was mapped to the cortical surface and aligned across individuals using surface-based registration. The spatial gradient of the group average myelin map provides an observer-independent measure of sharp transitions in myelin content across the surface—i.e. putative cortical areal borders. We found excellent agreement between the gradients of the myelin maps and the gradients of published probabilistic cytoarchitectonically defined cortical areas that were registered to the same surface-based atlas. For other cortical regions, we used published anatomical and functional information to make putative identifications of dozens of cortical areas or candidate areas. In general, primary and early unimodal association cortices are heavily myelinated and higher, multi-modal, association cortices are more lightly myelinated, but there are notable exceptions in the literature that are confirmed by our results. The overall pattern in the myelin maps also has important correlations with the developmental onset of subcortical white matter myelination, evolutionary cortical areal expansion in humans compared to macaques, postnatal cortical expansion in humans, and maps of neuronal density in non-human primates. PMID:21832190

  1. Distinct Cortical Pathways for Music and Speech Revealed by Hypothesis-Free Voxel Decomposition

    PubMed Central

    Norman-Haignere, Sam

    2015-01-01

    SUMMARY The organization of human auditory cortex remains unresolved, due in part to the small stimulus sets common to fMRI studies and the overlap of neural populations within voxels. To address these challenges, we measured fMRI responses to 165 natural sounds and inferred canonical response profiles (“components”) whose weighted combinations explained voxel responses throughout auditory cortex. This analysis revealed six components, each with interpretable response characteristics despite being unconstrained by prior functional hypotheses. Four components embodied selectivity for particular acoustic features (frequency, spectrotemporal modulation, pitch). Two others exhibited pronounced selectivity for music and speech, respectively, and were not explainable by standard acoustic features. Anatomically, music and speech selectivity concentrated in distinct regions of non-primary auditory cortex. However, music selectivity was weak in raw voxel responses, and its detection required a decomposition method. Voxel decomposition identifies primary dimensions of response variation across natural sounds, revealing distinct cortical pathways for music and speech. PMID:26687225

  2. Cortical and Subcortical Coordination of Visual Spatial Attention Revealed by Simultaneous EEG-fMRI Recording.

    PubMed

    Green, Jessica J; Boehler, Carsten N; Roberts, Kenneth C; Chen, Ling-Chia; Krebs, Ruth M; Song, Allen W; Woldorff, Marty G

    2017-08-16

    Visual spatial attention has been studied in humans with both electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) individually. However, due to the intrinsic limitations of each of these methods used alone, our understanding of the systems-level mechanisms underlying attentional control remains limited. Here, we examined trial-to-trial covariations of concurrently recorded EEG and fMRI in a cued visual spatial attention task in humans, which allowed delineation of both the generators and modulators of the cue-triggered event-related oscillatory brain activity underlying attentional control function. The fMRI activity in visual cortical regions contralateral to the cued direction of attention covaried positively with occipital gamma-band EEG, consistent with activation of cortical regions representing attended locations in space. In contrast, fMRI activity in ipsilateral visual cortical regions covaried inversely with occipital alpha-band oscillations, consistent with attention-related suppression of the irrelevant hemispace. Moreover, the pulvinar nucleus of the thalamus covaried with both of these spatially specific, attention-related, oscillatory EEG modulations. Because the pulvinar's neuroanatomical geometry makes it unlikely to be a direct generator of the scalp-recorded EEG, these covariational patterns appear to reflect the pulvinar's role as a regulatory control structure, sending spatially specific signals to modulate visual cortex excitability proactively. Together, these combined EEG/fMRI results illuminate the dynamically interacting cortical and subcortical processes underlying spatial attention, providing important insight not realizable using either method alone.SIGNIFICANCE STATEMENT Noninvasive recordings of changes in the brain's blood flow using functional magnetic resonance imaging and electrical activity using electroencephalography in humans have individually shown that shifting attention to a location in space

  3. Ultramicroscopy Reveals Axonal Transport Impairments in Cortical Motor Neurons at Prion Disease

    PubMed Central

    Ermolayev, Vladimir; Friedrich, Mike; Nozadze, Revaz; Cathomen, Toni; Klein, Michael A.; Harms, Gregory S.; Flechsig, Eckhard

    2009-01-01

    Abstract The functional imaging of neuronal circuits of the central nervous system is crucial for phenotype screenings or investigations of defects in neurodegenerative disorders. Current techniques yield either low penetration depth, yield poor resolution, or are restricted by the age of the animals. Here, we present a novel ultramicroscopy protocol for fluorescence imaging and three-dimensional reconstruction in the central nervous system of adult mice. In combination with tracing as a functional assay for axonal transport, retrogradely labeled descending motor neurons were visualized with >4 mm penetration depth. The analysis of the motor cortex shortly before the onset of clinical prion disease revealed that >80% neurons have functional impairments in axonal transport. Our study provides evidence that prion disease is associated with severe axonal transport defects in the cortical motor neurons and suggests a novel mechanism for prion-mediated neurodegeneration. PMID:19383482

  4. Transcriptome Sequencing Revealed Significant Alteration of Cortical Promoter Usage and Splicing in Schizophrenia

    PubMed Central

    Wu, Jing Qin; Wang, Xi; Beveridge, Natalie J.; Tooney, Paul A.; Scott, Rodney J.; Carr, Vaughan J.; Cairns, Murray J.

    2012-01-01

    Background While hybridization based analysis of the cortical transcriptome has provided important insight into the neuropathology of schizophrenia, it represents a restricted view of disease-associated gene activity based on predetermined probes. By contrast, sequencing technology can provide un-biased analysis of transcription at nucleotide resolution. Here we use this approach to investigate schizophrenia-associated cortical gene expression. Methodology/Principal Findings The data was generated from 76 bp reads of RNA-Seq, aligned to the reference genome and assembled into transcripts for quantification of exons, splice variants and alternative promoters in postmortem superior temporal gyrus (STG/BA22) from 9 male subjects with schizophrenia and 9 matched non-psychiatric controls. Differentially expressed genes were then subjected to further sequence and functional group analysis. The output, amounting to more than 38 Gb of sequence, revealed significant alteration of gene expression including many previously shown to be associated with schizophrenia. Gene ontology enrichment analysis followed by functional map construction identified three functional clusters highly relevant to schizophrenia including neurotransmission related functions, synaptic vesicle trafficking, and neural development. Significantly, more than 2000 genes displayed schizophrenia-associated alternative promoter usage and more than 1000 genes showed differential splicing (FDR<0.05). Both types of transcriptional isoforms were exemplified by reads aligned to the neurodevelopmentally significant doublecortin-like kinase 1 (DCLK1) gene. Conclusions This study provided the first deep and un-biased analysis of schizophrenia-associated transcriptional diversity within the STG, and revealed variants with important implications for the complex pathophysiology of schizophrenia. PMID:22558445

  5. Dynamically Allocated Hub in Task-Evoked Network Predicts the Vulnerable Prefrontal Locus for Contextual Memory Retrieval in Macaques.

    PubMed

    Osada, Takahiro; Adachi, Yusuke; Miyamoto, Kentaro; Jimura, Koji; Setsuie, Rieko; Miyashita, Yasushi

    2015-06-01

    Neuroimaging and neurophysiology have revealed that multiple areas in the prefrontal cortex (PFC) are activated in a specific memory task, but severity of impairment after PFC lesions is largely different depending on which activated area is damaged. The critical relationship between lesion sites and impairments has not yet been given a clear mechanistic explanation. Although recent works proposed that a whole-brain network contains hubs that play integrative roles in cortical information processing, this framework relying on an anatomy-based structural network cannot account for the vulnerable locus for a specific task, lesioning of which would bring impairment. Here, we hypothesized that (i) activated PFC areas dynamically form an ordered network centered at a task-specific "functional hub" and (ii) the lesion-effective site corresponds to the "functional hub," but not to a task-invariant "structural hub." To test these hypotheses, we conducted functional magnetic resonance imaging experiments in macaques performing a temporal contextual memory task. We found that the activated areas formed a hierarchical hub-centric network based on task-evoked directed connectivity, differently from the anatomical network reflecting axonal projection patterns. Using a novel simulated-lesion method based on support vector machine, we estimated severity of impairment after lesioning of each area, which accorded well with a known dissociation in contextual memory impairment in macaques (impairment after lesioning in area 9/46d, but not in area 8Ad). The predicted severity of impairment was proportional to the network "hubness" of the virtually lesioned area in the task-evoked directed connectivity network, rather than in the anatomical network known from tracer studies. Our results suggest that PFC areas dynamically and cooperatively shape a functional hub-centric network to reallocate the lesion-effective site depending on the cognitive processes, apart from static anatomical

  6. Aircraft Propeller Hub Repair

    SciTech Connect

    Muth, Thomas R.; Peter, William H.

    2015-02-13

    The team performed a literature review, conducted residual stress measurements, performed failure analysis, and demonstrated a solid state additive manufacturing repair technique on samples removed from a scrapped propeller hub. The team evaluated multiple options for hub repair that included existing metal buildup technologies that the Federal Aviation Administration (FAA) has already embraced, such as cold spray, high velocity oxy-fuel deposition (HVOF), and plasma spray. In addition the team helped Piedmont Propulsion Systems, LLC (PPS) evaluate three potential solutions that could be deployed at different stages in the life cycle of aluminum alloy hubs, in addition to the conventional spray coating method for repair. For new hubs, a machining practice to prevent fretting with the steel drive shaft was recommended. For hubs that were refurbished with some material remaining above the minimal material condition (MMC), a silver interface applied by an electromagnetic pulse additive manufacturing method was recommended. For hubs that were at or below the MMC, a solid state additive manufacturing technique using ultrasonic welding (UW) of thin layers of 7075 aluminum to the hub interface was recommended. A cladding demonstration using the UW technique achieved mechanical bonding of the layers showing promise as a viable repair method.

  7. A systematic integrated analysis of brain expression profiles reveals YAP1 and other prioritized hub genes as important upstream regulators in Alzheimer's disease.

    PubMed

    Xu, Min; Zhang, Deng-Feng; Luo, Rongcan; Wu, Yong; Zhou, Hejiang; Kong, Li-Li; Bi, Rui; Yao, Yong-Gang

    2017-09-15

    Profiling the spatial-temporal expression pattern and characterizing the regulatory networks of brain tissues are vital for understanding the pathophysiology of Alzheimer's disease (AD). We performed a systematic integrated analysis of expression profiles of AD-affected brain tissues (684 AD and 562 controls). A network-based convergent functional genomic approach was used to prioritize possible regulator genes during AD development, followed by functional characterization. We generated a complete list of differentially expressed genes and hub genes of the transcriptomic network in AD brain and constructed a Web server (www.alzdata.org) for public access. Seventeen hub genes active at the early stages, especially YAP1, were recognized as upstream regulators of the AD network. Cellular assays proved that early alteration of YAP1 could promote AD by influencing the whole transcriptional network. Early expression disturbance of hub genes is an important feature of AD development, and interfering with this process may reverse the disease progression. Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

  8. Multiple markers of cortical morphology reveal evidence of supragranular thinning in schizophrenia

    PubMed Central

    Wagstyl, K; Ronan, L; Whitaker, K J; Goodyer, I M; Roberts, N; Crow, T J; Fletcher, P C

    2016-01-01

    In vivo structural neuroimaging can reliably identify changes to cortical morphology and its regional variation but cannot yet relate these changes to specific cortical layers. We propose, however, that by synthesizing principles of cortical organization, including relative contributions of different layers to sulcal and gyral thickness, regional patterns of variation in thickness of different layers across the cortical sheet and profiles of layer variation across functional hierarchies, it is possible to develop indirect morphological measures as markers of more specific cytoarchitectural changes. We developed four indirect measures sensitive to changes specifically occurring in supragranular cortical layers, and applied these to test the hypothesis that supragranular layers are disproportionately affected in schizophrenia. Our findings from the four different measures converge to indicate a predominance of supragranular thinning in schizophrenia, independent of medication and illness duration. We propose that these indirect measures offer novel ways of identifying layer-specific cortical changes, offering complementary in vivo observations to existing post-mortem studies. PMID:27070408

  9. Distinct Cortical Pathways for Music and Speech Revealed by Hypothesis-Free Voxel Decomposition.

    PubMed

    Norman-Haignere, Sam; Kanwisher, Nancy G; McDermott, Josh H

    2015-12-16

    The organization of human auditory cortex remains unresolved, due in part to the small stimulus sets common to fMRI studies and the overlap of neural populations within voxels. To address these challenges, we measured fMRI responses to 165 natural sounds and inferred canonical response profiles ("components") whose weighted combinations explained voxel responses throughout auditory cortex. This analysis revealed six components, each with interpretable response characteristics despite being unconstrained by prior functional hypotheses. Four components embodied selectivity for particular acoustic features (frequency, spectrotemporal modulation, pitch). Two others exhibited pronounced selectivity for music and speech, respectively, and were not explainable by standard acoustic features. Anatomically, music and speech selectivity concentrated in distinct regions of non-primary auditory cortex. However, music selectivity was weak in raw voxel responses, and its detection required a decomposition method. Voxel decomposition identifies primary dimensions of response variation across natural sounds, revealing distinct cortical pathways for music and speech. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Joint cross-correlation analysis reveals complex, time-dependent functional relationship between cortical neurons and arm electromyograms

    PubMed Central

    Zhuang, Katie Z.; Lebedev, Mikhail A.

    2014-01-01

    Correlation between cortical activity and electromyographic (EMG) activity of limb muscles has long been a subject of neurophysiological studies, especially in terms of corticospinal connectivity. Interest in this issue has recently increased due to the development of brain-machine interfaces with output signals that mimic muscle force. For this study, three monkeys were implanted with multielectrode arrays in multiple cortical areas. One monkey performed self-timed touch pad presses, whereas the other two executed arm reaching movements. We analyzed the dynamic relationship between cortical neuronal activity and arm EMGs using a joint cross-correlation (JCC) analysis that evaluated trial-by-trial correlation as a function of time intervals within a trial. JCCs revealed transient correlations between the EMGs of multiple muscles and neural activity in motor, premotor and somatosensory cortical areas. Matching results were obtained using spike-triggered averages corrected by subtracting trial-shuffled data. Compared with spike-triggered averages, JCCs more readily revealed dynamic changes in cortico-EMG correlations. JCCs showed that correlation peaks often sharpened around movement times and broadened during delay intervals. Furthermore, JCC patterns were directionally selective for the arm-reaching task. We propose that such highly dynamic, task-dependent and distributed relationships between cortical activity and EMGs should be taken into consideration for future brain-machine interfaces that generate EMG-like signals. PMID:25210153

  11. Online Stimulus Optimization Rapidly Reveals Multidimensional Selectivity in Auditory Cortical Neurons

    PubMed Central

    Hancock, Kenneth E.; Sen, Kamal

    2014-01-01

    Neurons in sensory brain regions shape our perception of the surrounding environment through two parallel operations: decomposition and integration. For example, auditory neurons decompose sounds by separately encoding their frequency, temporal modulation, intensity, and spatial location. Neurons also integrate across these various features to support a unified perceptual gestalt of an auditory object. At higher levels of a sensory pathway, neurons may select for a restricted region of feature space defined by the intersection of multiple, independent stimulus dimensions. To further characterize how auditory cortical neurons decompose and integrate multiple facets of an isolated sound, we developed an automated procedure that manipulated five fundamental acoustic properties in real time based on single-unit feedback in awake mice. Within several minutes, the online approach converged on regions of the multidimensional stimulus manifold that reliably drove neurons at significantly higher rates than predefined stimuli. Optimized stimuli were cross-validated against pure tone receptive fields and spectrotemporal receptive field estimates in the inferior colliculus and primary auditory cortex. We observed, from midbrain to cortex, increases in both level invariance and frequency selectivity, which may underlie equivalent sparseness of responses in the two areas. We found that onset and steady-state spike rates increased proportionately as the stimulus was tailored to the multidimensional receptive field. By separately evaluating the amount of leverage each sound feature exerted on the overall firing rate, these findings reveal interdependencies between stimulus features as well as hierarchical shifts in selectivity and invariance that may go unnoticed with traditional approaches. PMID:24990917

  12. Visuotopic cortical connectivity underlying attention revealed with white-matter tractography.

    PubMed

    Greenberg, Adam S; Verstynen, Timothy; Chiu, Yu-Chin; Yantis, Steven; Schneider, Walter; Behrmann, Marlene

    2012-02-22

    Visual attention selects behaviorally relevant information for detailed processing by resolving competition for representation among stimuli in retinotopically organized visual cortex. The signals that control this attentional biasing are thought to arise in a frontoparietal network of several brain regions, including posterior parietal cortex. Recent studies have revealed a topographic organization in the intraparietal sulcus (IPS) that mirrors the retinotopic organization in visual cortex, suggesting that connectivity between these regions might provide the mechanism by which attention acts on early cortical representations. Using white-matter imaging and functional MRI, we examined the connectivity between two topographic regions of IPS and six retinotopically defined areas in visual cortex. We observed a strong positive correlation between attention modulations in visual cortex and connectivity of posterior IPS, suggesting that these white-matter connections mediate the attention signals that resolve competition among stimuli for representation in visual cortex. Furthermore, we found that connectivity between IPS and V1 consistently respects visuotopic boundaries, whereas connections to V2 and V3/VP disperse by 60%. This pattern is consistent with changes in receptive field size across regions and suggests that a primary role of posterior IPS is to code spatially specific visual information. In summary, we have identified white-matter pathways that are ideally suited to carry attentional biasing signals in visuotopic coordinates from parietal control regions to sensory regions in humans. These results provide critical evidence for the biased competition theory of attention and specify neurobiological constraints on the functional brain organization of visual attention.

  13. Combined TMS and FMRI reveal dissociable cortical pathways for dynamic and static face perception.

    PubMed

    Pitcher, David; Duchaine, Bradley; Walsh, Vincent

    2014-09-08

    Faces contain structural information, for identifying individuals, as well as changeable information, which can convey emotion and direct attention. Neuroimaging studies reveal brain regions that exhibit preferential responses to invariant [1, 2] or changeable [3-5] facial aspects but the functional connections between these regions are unknown. We addressed this issue by causally disrupting two face-selective regions with thetaburst transcranial magnetic stimulation (TBS) and measuring the effects of this disruption in local and remote face-selective regions with functional magnetic resonance imaging (fMRI). Participants were scanned, over two sessions, while viewing dynamic or static faces and objects. During these sessions, TBS was delivered over the right occipital face area (rOFA) or right posterior superior temporal sulcus (rpSTS). Disruption of the rOFA reduced the neural response to both static and dynamic faces in the downstream face-selective region in the fusiform gyrus. In contrast, the response to dynamic and static faces was doubly dissociated in the rpSTS. Namely, disruption of the rOFA reduced the response to static but not dynamic faces, while disruption of the rpSTS itself reduced the response to dynamic but not static faces. These results suggest that dynamic and static facial aspects are processed via dissociable cortical pathways that begin in early visual cortex, a conclusion inconsistent with current models of face perception [6-9].

  14. Visuotopic Cortical Connectivity Underlying Attention Revealed with White-Matter Tractography

    PubMed Central

    Greenberg, Adam S.; Verstynen, Timothy; Chiu, Yu-Chin; Yantis, Steven; Schneider, Walter; Behrmann, Marlene

    2012-01-01

    Visual attention selects behaviorally relevant information for detailed processing by resolving competition for representation among stimuli in retinotopically organized visual cortex. The signals that control this attentional biasing are thought to arise in a frontoparietal network of several brain regions, including posterior parietal cortex. Recent studies have revealed a topographic organization in the intraparietal sulcus (IPS) that mirrors the retinotopic organization in visual cortex, suggesting that connectivity between these regions might provide the mechanism by which attention acts on early cortical representations. Using white-matter imaging and functional MRI, we examined the connectivity between two topographic regions of IPS and six retinotopically defined areas in visual cortex. We observed a strong positive correlation between attention modulations in visual cortex and connectivity of posterior IPS, suggesting that these white-matter connections mediate the attention signals that resolve competition among stimuli for representation in visual cortex. Furthermore, we found that connectivity between IPS and V1 consistently respects visuotopic boundaries, whereas connections to V2 and V3/VP disperse by 60%. This pattern is consistent with changes in receptive field size across regions and suggests that a primary role of posterior IPS is to code spatially specific visual information. In summary, we have identified white-matter pathways that are ideally suited to carry attentional biasing signals in visuotopic coordinates from parietal control regions to sensory regions in humans. These results provide critical evidence for the biased competition theory of attention and specify neurobiological constraints on the functional brain organization of visual attention. PMID:22357860

  15. Online stimulus optimization rapidly reveals multidimensional selectivity in auditory cortical neurons.

    PubMed

    Chambers, Anna R; Hancock, Kenneth E; Sen, Kamal; Polley, Daniel B

    2014-07-02

    Neurons in sensory brain regions shape our perception of the surrounding environment through two parallel operations: decomposition and integration. For example, auditory neurons decompose sounds by separately encoding their frequency, temporal modulation, intensity, and spatial location. Neurons also integrate across these various features to support a unified perceptual gestalt of an auditory object. At higher levels of a sensory pathway, neurons may select for a restricted region of feature space defined by the intersection of multiple, independent stimulus dimensions. To further characterize how auditory cortical neurons decompose and integrate multiple facets of an isolated sound, we developed an automated procedure that manipulated five fundamental acoustic properties in real time based on single-unit feedback in awake mice. Within several minutes, the online approach converged on regions of the multidimensional stimulus manifold that reliably drove neurons at significantly higher rates than predefined stimuli. Optimized stimuli were cross-validated against pure tone receptive fields and spectrotemporal receptive field estimates in the inferior colliculus and primary auditory cortex. We observed, from midbrain to cortex, increases in both level invariance and frequency selectivity, which may underlie equivalent sparseness of responses in the two areas. We found that onset and steady-state spike rates increased proportionately as the stimulus was tailored to the multidimensional receptive field. By separately evaluating the amount of leverage each sound feature exerted on the overall firing rate, these findings reveal interdependencies between stimulus features as well as hierarchical shifts in selectivity and invariance that may go unnoticed with traditional approaches.

  16. Cortical silent period reveals differences between adductor spasmodic dysphonia and muscle tension dysphonia

    PubMed Central

    Samargia, Sharyl; Schmidt, Rebekah; Kimberley, Teresa Jacobson

    2015-01-01

    Background The pathophysiology of adductor spasmodic dysphonia (AdSD), like other focal dystonias, is largely unknown. Objective The purposes of this study were to determine 1) cortical excitability differences between AdSD, muscle tension dysphonia (MTD) and healthy controls 2) distribution of potential differences in cranial or skeletal muscle, and 3) if cortical excitability measures assist in the differential diagnosis of AdSD and MTD. Methods 10 participants with adductor spasmodic dysphonia, 8 with muscle tension dysphonia and 10 healthy controls received single and paired pulse transcranial magnetic stimulation (TMS) to the primary motor cortex contralateral to tested muscles, first dorsal interosseus (FDI) and masseter. We tested the hypothesis that cortical excitability measures in AdSD would be significantly different than in MTD and healthy. In addition, we hypothesized there would be a correlation between cortical excitability measures and clinical voice severity in AdSD. Results Cortical silent period (CSP) duration in masseter and FDI was significantly shorter in AdSD than MTD and healthy controls. Other measures failed to demonstrate differences. Conclusion There are differences in cortical excitability between AdSD, MTD and healthy controls. These differences in the cortical measure of both the FDI and masseter muscles in AdSD suggest widespread dysfunction of the GABAB mechanism may be a pathophysiologic feature of AdSD, similar to other forms of focal dystonia. Further exploration of the use of TMS to assist in the differential diagnosis of AdSD and MTD is warranted. PMID:26089309

  17. Electrophysiological Potentials Reveal Cortical Mechanisms for Mental Imagery, Mental Simulation, and Grounded (Embodied) Cognition

    PubMed Central

    Schendan, Haline E.; Ganis, Giorgio

    2012-01-01

    Grounded cognition theory proposes that cognition, including meaning, is grounded in sensorimotor processing. The mechanism for grounding cognition is mental simulation, which is a type of mental imagery that re-enacts modal processing. To reveal top-down, cortical mechanisms for mental simulation of shape, event-related potentials were recorded to face and object pictures preceded by mental imagery. Mental imagery of the identical face or object picture (congruous condition) facilitated not only categorical perception (VPP/N170) but also later visual knowledge [N3(00) complex] and linguistic knowledge (N400) for faces more than objects, and strategic semantic analysis (late positive complex) between 200 and 700 ms. The later effects resembled semantic congruity effects with pictures. Mental imagery also facilitated category decisions, as a P3 peaked earlier for congruous than incongruous (other category) pictures, resembling the case when identical pictures repeat immediately. Thus mental imagery mimics semantic congruity and immediate repetition priming processes with pictures. Perception control results showed the opposite for faces and were in the same direction for objects: Perceptual repetition adapts (and so impairs) processing of perceived faces from categorical perception onward, but primes processing of objects during categorical perception, visual knowledge processes, and strategic semantic analysis. For both imagery and perception, differences between faces and objects support domain-specificity and indicate that cognition is grounded in modal processing. Altogether, this direct neural evidence reveals that top-down processes of mental imagery sustain an imagistic representation that mimics perception well enough to prime subsequent perception and cognition. Findings also suggest that automatic mental simulation of the visual shape of faces and objects operates between 200 and 400 ms, and strategic mental simulation operates between 400 and 700

  18. Electrophysiological potentials reveal cortical mechanisms for mental imagery, mental simulation, and grounded (embodied) cognition.

    PubMed

    Schendan, Haline E; Ganis, Giorgio

    2012-01-01

    Grounded cognition theory proposes that cognition, including meaning, is grounded in sensorimotor processing. The mechanism for grounding cognition is mental simulation, which is a type of mental imagery that re-enacts modal processing. To reveal top-down, cortical mechanisms for mental simulation of shape, event-related potentials were recorded to face and object pictures preceded by mental imagery. Mental imagery of the identical face or object picture (congruous condition) facilitated not only categorical perception (VPP/N170) but also later visual knowledge [N3(00) complex] and linguistic knowledge (N400) for faces more than objects, and strategic semantic analysis (late positive complex) between 200 and 700 ms. The later effects resembled semantic congruity effects with pictures. Mental imagery also facilitated category decisions, as a P3 peaked earlier for congruous than incongruous (other category) pictures, resembling the case when identical pictures repeat immediately. Thus mental imagery mimics semantic congruity and immediate repetition priming processes with pictures. Perception control results showed the opposite for faces and were in the same direction for objects: Perceptual repetition adapts (and so impairs) processing of perceived faces from categorical perception onward, but primes processing of objects during categorical perception, visual knowledge processes, and strategic semantic analysis. For both imagery and perception, differences between faces and objects support domain-specificity and indicate that cognition is grounded in modal processing. Altogether, this direct neural evidence reveals that top-down processes of mental imagery sustain an imagistic representation that mimics perception well enough to prime subsequent perception and cognition. Findings also suggest that automatic mental simulation of the visual shape of faces and objects operates between 200 and 400 ms, and strategic mental simulation operates between 400 and 700 ms.

  19. Remodelling of cortical actin where lytic granules dock at natural killer cell immune synapses revealed by super-resolution microscopy.

    PubMed

    Brown, Alice C N; Oddos, Stephane; Dobbie, Ian M; Alakoskela, Juha-Matti; Parton, Richard M; Eissmann, Philipp; Neil, Mark A A; Dunsby, Christopher; French, Paul M W; Davis, Ilan; Davis, Daniel M

    2011-09-01

    Natural Killer (NK) cells are innate immune cells that secrete lytic granules to directly kill virus-infected or transformed cells across an immune synapse. However, a major gap in understanding this process is in establishing how lytic granules pass through the mesh of cortical actin known to underlie the NK cell membrane. Research has been hampered by the resolution of conventional light microscopy, which is too low to resolve cortical actin during lytic granule secretion. Here we use two high-resolution imaging techniques to probe the synaptic organisation of NK cell receptors and filamentous (F)-actin. A combination of optical tweezers and live cell confocal microscopy reveals that microclusters of NKG2D assemble into a ring-shaped structure at the centre of intercellular synapses, where Vav1 and Grb2 also accumulate. Within this ring-shaped organisation of NK cell proteins, lytic granules accumulate for secretion. Using 3D-structured illumination microscopy (3D-SIM) to gain super-resolution of ~100 nm, cortical actin was detected in a central region of the NK cell synapse irrespective of whether activating or inhibitory signals dominate. Strikingly, the periodicity of the cortical actin mesh increased in specific domains at the synapse when the NK cell was activated. Two-colour super-resolution imaging revealed that lytic granules docked precisely in these domains which were also proximal to where the microtubule-organising centre (MTOC) polarised. Together, these data demonstrate that remodelling of the cortical actin mesh occurs at the central region of the cytolytic NK cell immune synapse. This is likely to occur for other types of cell secretion and also emphasises the importance of emerging super-resolution imaging technology for revealing new biology.

  20. Elicitation interval dependent spatiotemporal evolution of cortical spreading depression waves revealed by optical intrinsic signal imaging

    NASA Astrophysics Data System (ADS)

    Chen, Shangbin; Gong, Hui; Zeng, Shaoqun; Luo, Qingming; Li, Pengcheng

    2007-02-01

    This study aimed to investigate the variation of propagation patterns of successive cortical spreading depression (CSD) waves induced by K + or pinprick in rat cortex. In the K + induction group, 18 Sprague-Dawley rats under Î+/--chloralose/urethane anesthesia were used to elicit CSD by 1 M KCl solution in the frontal cortex. Optical intrinsic signal imaging (OISI) at an isosbestic point of hemoglobin (550 nm) was applied to examine regional cerebral blood volume (CBV) changes in the parieto-occipital cortex. In 6 of the 18 rats, OISI was performed in conjunction with DC potential recording of the cortex. The results of this group were reported previously. In the pinprick group, 6 rats were used to induce CSD by pinprick with 8 min interval, and the other 6 rats were pricked with 4 min. CBV changes during CSD appeared as repetitive propagation of wave-like hyperemia at a speed of 3.7+/-0.4 mm/min, which was characterized by a significant negative peak (-14.3+/-3.2%) in the reflectance signal. Except for the first CSD wave, the following waves don't spread fully in the observed cortex all the time and they might abort in the medial area. Independent on the stimulation of pinprick or K+, a short interval of the current CSD to the last CSD no more than 4 min would induce the current CSD be partially propagated. For the first time, the data reveals the time-varying propagation patterns of CSD waves might be affected by the interval between CSD waves. The results suggest that the propagation patterns of a series of CSD waves are time-varying in different regions of rat cortex, and the variation is related to the interval between CSD waves.

  1. Epileptic Networks in Focal Cortical Dysplasia Revealed Using Electroencephalography–Functional Magnetic Resonance Imaging

    PubMed Central

    Thornton, Rachel; Vulliemoz, Serge; Rodionov, Roman; Carmichael, David W; Chaudhary, Umair J; Diehl, Beate; Laufs, Helmut; Vollmar, Christian; McEvoy, Andrew W; Walker, Matthew C; Bartolomei, Fabrice; Guye, Maxime; Chauvel, Patrick; Duncan, John S; Lemieux, Louis

    2011-01-01

    Objective Surgical treatment of focal epilepsy in patients with focal cortical dysplasia (FCD) is most successful if all epileptogenic tissue is resected. This may not be evident on structural magnetic resonance imaging (MRI), so intracranial electroencephalography (icEEG) is needed to delineate the seizure onset zone (SOZ). EEG-functional MRI (fMRI) can reveal interictal discharge (IED)-related hemodynamic changes in the irritative zone (IZ). We assessed the value of EEG-fMRI in patients with FCD-associated focal epilepsy by examining the relationship between IED-related hemodynamic changes, icEEG findings, and postoperative outcome. Methods Twenty-three patients with FCD-associated focal epilepsy undergoing presurgical evaluation including icEEG underwent simultaneous EEG-fMRI at 3T. IED-related hemodynamic changes were modeled, and results were overlaid on coregistered T1-weighted MRI scans fused with computed tomography scans showing the intracranial electrodes. IED-related hemodynamic changes were compared with the SOZ on icEEG and postoperative outcome at 1 year. Results Twelve of 23 patients had IEDs during recording, and 11 of 12 had significant IED-related hemodynamic changes. The fMRI results were concordant with the SOZ in 5 of 11 patients, all of whom had a solitary SOZ on icEEG. Four of 5 had >50% reduction in seizure frequency following resective surgery. The remaining 6 of 11 patients had widespread or discordant regions of IED-related fMRI signal change. Five of 6 had either a poor surgical outcome (<50% reduction in seizure frequency) or widespread SOZ precluding surgery. Interpretation Comparison of EEG-fMRI with icEEG suggests that EEG-fMRI may provide useful additional information about the SOZ in FCD. Widely distributed discordant regions of IED-related hemodynamic change appear to be associated with a widespread SOZ and poor postsurgical outcome. ANN NEUROL 2011 PMID:22162063

  2. Human cortical responses to slow and fast binaural beats reveal multiple mechanisms of binaural hearing.

    PubMed

    Ross, Bernhard; Miyazaki, Takahiro; Thompson, Jessica; Jamali, Shahab; Fujioka, Takako

    2014-10-15

    When two tones with slightly different frequencies are presented to both ears, they interact in the central auditory system and induce the sensation of a beating sound. At low difference frequencies, we perceive a single sound, which is moving across the head between the left and right ears. The percept changes to loudness fluctuation, roughness, and pitch with increasing beat rate. To examine the neural representations underlying these different perceptions, we recorded neuromagnetic cortical responses while participants listened to binaural beats at a continuously varying rate between 3 Hz and 60 Hz. Binaural beat responses were analyzed as neuromagnetic oscillations following the trajectory of the stimulus rate. Responses were largest in the 40-Hz gamma range and at low frequencies. Binaural beat responses at 3 Hz showed opposite polarity in the left and right auditory cortices. We suggest that this difference in polarity reflects the opponent neural population code for representing sound location. Binaural beats at any rate induced gamma oscillations. However, the responses were largest at 40-Hz stimulation. We propose that the neuromagnetic gamma oscillations reflect postsynaptic modulation that allows for precise timing of cortical neural firing. Systematic phase differences between bilateral responses suggest that separate sound representations of a sound object exist in the left and right auditory cortices. We conclude that binaural processing at the cortical level occurs with the same temporal acuity as monaural processing whereas the identification of sound location requires further interpretation and is limited by the rate of object representations. Copyright © 2014 the American Physiological Society.

  3. Cell autonomous defects in cortical development revealed by two-color chimera analysis.

    PubMed

    Kwiatkowski, Adam V; Garner, Craig C; Nelson, W James; Gertler, Frank B

    2009-05-01

    A complex program of cell intrinsic and extrinsic signals guide cortical development. Although genetic studies in mice have uncovered roles for numerous genes and gene families in multiple aspects of corticogenesis, determining their cell autonomous functions is often complicated by pleiotropic defects. Here we describe a novel lentiviral-based method to analyze cell autonomy by generating two-color chimeric mouse embryos. Ena/VASP-deficient mutant and control embryonic stem (ES) cells were labeled with different fluorescent chimeric proteins (EGFP and mCherry) that were modified to bind to the plasma membrane. These labeled ES cells were used to generate two-color chimeric embryos possessing two genetically distinct populations of cortical cells, permitting multiple aspects of neuronal morphogenesis to be analyzed and compared between the two cell populations. We observed little difference between the ability of control and Ena/VASP-deficient cells to contribute to cortical organization during development. In contrast, we observed axon fiber tracts originating from control neurons but not Ena/VASP-deficient neurons, indicating that loss of Ena/VASP causes a cell autonomous defect in cortical axon formation. This technique could be applied to determine other cell autonomous functions in different stages of cortical development.

  4. Surface-based morphometry reveals distinct cortical thickness and surface area profiles in Williams syndrome.

    PubMed

    Green, Tamar; Fierro, Kyle C; Raman, Mira M; Saggar, Manish; Sheau, Kristen E; Reiss, Allan L

    2016-04-01

    Morphometric investigations of brain volumes in Williams syndrome (WS) consistently show significant reductions in gray matter volume compared to controls. Cortical thickness (CT) and surface area (SA) are two constituent parts of cortical gray matter volume that are considered genetically distinguishable features of brain morphology. Yet, little is known about the independent contribution of cortical CT and SA to these volumetric differences in WS. Thus, our objectives were: (i) to evaluate whether the microdeletion in chromosome 7 associated with WS has a distinct effect on CT and SA, and (ii) to evaluate age-related variations in CT and SA within WS. We compared CT and SA values in 44 individuals with WS to 49 age- and sex-matched typically developing controls. Between-group differences in CT and SA were evaluated across two age groups: young (age range 6.6-18.9 years), and adults (age range 20.2-51.5 years). Overall, we found contrasting effects of WS on cortical thickness (increases) and surface area (decreases). With respect to brain topography, the between-group pattern of CT differences showed a scattered pattern while the between-group surface area pattern was widely distributed throughout the brain. In the adult subgroup, we observed a cluster of increases in cortical thickness in WS across the brain that was not observed in the young subgroup. Our findings suggest that extensive early reductions in surface area are the driving force for the overall reduction in brain volume in WS. The age-related cortical thickness findings might reflect delayed or even arrested development of specific brain regions in WS. © 2016 Wiley Periodicals, Inc.

  5. Recombinant Probes Reveal Dynamic Localization of CaMKIIα within Somata of Cortical Neurons

    PubMed Central

    Mora, Rudy J.; Roberts, Richard W.

    2013-01-01

    In response to NMDA receptor stimulation, CaMKIIα moves rapidly from a diffuse distribution within the shafts of neuronal dendrites to a clustered postsynaptic distribution. However, less is known about CaMKIIα localization and trafficking within neuronal somata. Here we use a novel recombinant probe capable of labeling endogenous CaMKIIα in living rat neurons to examine its localization and trafficking within the somata of cortical neurons. This probe, which was generated using an mRNA display selection, binds to endogenous CaMKIIα at high affinity and specificity following expression in rat cortical neurons in culture. In ∼45% of quiescent cortical neurons, labeled clusters of CaMKIIα 1–4 μm in diameter were present. Upon exposure to glutamate and glycine, CaMKIIα clusters disappeared in a Ca2+-dependent manner within seconds. Moreover, minutes after the removal of glutamate and glycine, the clusters returned to their original configuration. The clusters, which also appear in cortical neurons in sections taken from mouse brains, contain actin and disperse upon exposure to cytochalasin D, an actin depolymerizer. In conclusion, within the soma, CaMKII localizes and traffics in a manner that is distinct from its localization and trafficking within the dendrites. PMID:24005308

  6. Evidence of functional connectivity between auditory cortical areas revealed by amplitude modulation sound processing.

    PubMed

    Guéguin, Marie; Le Bouquin-Jeannès, Régine; Faucon, Gérard; Chauvel, Patrick; Liégeois-Chauvel, Catherine

    2007-02-01

    The human auditory cortex includes several interconnected areas. A better understanding of the mechanisms involved in auditory cortical functions requires a detailed knowledge of neuronal connectivity between functional cortical regions. In human, it is difficult to track in vivo neuronal connectivity. We investigated the interarea connection in vivo in the auditory cortex using a method of directed coherence (DCOH) applied to depth auditory evoked potentials (AEPs). This paper presents simultaneous AEPs recordings from insular gyrus (IG), primary and secondary cortices (Heschl's gyrus and planum temporale), and associative areas (Brodmann area [BA] 22) with multilead intracerebral electrodes in response to sinusoidal modulated white noises in 4 epileptic patients who underwent invasive monitoring with depth electrodes for epilepsy surgery. DCOH allowed estimation of the causality between 2 signals recorded from different cortical sites. The results showed 1) a predominant auditory stream within the primary auditory cortex from the most medial region to the most lateral one whatever the modulation frequency, 2) unidirectional functional connection from the primary to secondary auditory cortex, 3) a major auditory propagation from the posterior areas to the anterior ones, particularly at 8, 16, and 32 Hz, and 4) a particular role of Heschl's sulcus dispatching information to the different auditory areas. These findings suggest that cortical processing of auditory information is performed in serial and parallel streams. Our data showed that the auditory propagation could not be associated to a unidirectional traveling wave but to a constant interaction between these areas that could reflect the large adaptive and plastic capacities of auditory cortex. The role of the IG is discussed.

  7. Distribution of neurons in functional areas of the mouse cerebral cortex reveals quantitatively different cortical zones.

    PubMed

    Herculano-Houzel, Suzana; Watson, Charles; Paxinos, George

    2013-01-01

    How are neurons distributed along the cortical surface and across functional areas? Here we use the isotropic fractionator (Herculano-Houzel and Lent, 2005) to analyze the distribution of neurons across the entire isocortex of the mouse, divided into 18 functional areas defined anatomically. We find that the number of neurons underneath a surface area (the N/A ratio) varies 4.5-fold across functional areas and neuronal density varies 3.2-fold. The face area of S1 contains the most neurons, followed by motor cortex and the primary visual cortex. Remarkably, while the distribution of neurons across functional areas does not accompany the distribution of surface area, it mirrors closely the distribution of cortical volumes-with the exception of the visual areas, which hold more neurons than expected for their volume. Across the non-visual cortex, the volume of individual functional areas is a shared linear function of their number of neurons, while in the visual areas, neuronal densities are much higher than in all other areas. In contrast, the 18 functional areas cluster into three different zones according to the relationship between the N/A ratio and cortical thickness and neuronal density: these three clusters can be called visual, sensory, and, possibly, associative. These findings are remarkably similar to those in the human cerebral cortex (Ribeiro et al., 2013) and suggest that, like the human cerebral cortex, the mouse cerebral cortex comprises two zones that differ in how neurons form the cortical volume, and three zones that differ in how neurons are distributed underneath the cortical surface, possibly in relation to local differences in connectivity through the white matter. Our results suggest that beyond the developmental divide into visual and non-visual cortex, functional areas initially share a common distribution of neurons along the parenchyma that become delimited into functional areas according to the pattern of connectivity established later.

  8. Fluctuation Analysis of Centrosomes Reveals a Cortical Function of Kinesin-1

    PubMed Central

    Winkler, Franziska; Gummalla, Maheshwar; Künneke, Lutz; Lv, Zhiyi; Zippelius, Annette; Aspelmeier, Timo; Grosshans, Jörg

    2015-01-01

    The actin and microtubule networks form the dynamic cytoskeleton. Network dynamics is driven by molecular motors applying force onto the networks and the interactions between the networks. Here we assay the dynamics of centrosomes in the scale of seconds as a proxy for the movement of microtubule asters. With this assay we want to detect the role of specific motors and of network interaction. During interphase of syncytial embryos of Drosophila, cortical actin and the microtubule network depend on each other. Centrosomes induce cortical actin to form caps, whereas F-actin anchors microtubules to the cortex. In addition, lateral interactions between microtubule asters are assumed to be important for regular spatial organization of the syncytial embryo. The functional interaction between the microtubule asters and cortical actin has been largely analyzed in a static manner, so far. We recorded the movement of centrosomes at 1 Hz and analyzed their fluctuations for two processes—pair separation and individual movement. We found that F-actin is required for directional movements during initial centrosome pair separation, because separation proceeds in a diffusive manner in latrunculin-injected embryos. For assaying individual movement, we established a fluctuation parameter as the deviation from temporally and spatially slowly varying drift movements. By analysis of mutant and drug-injected embryos, we found that the fluctuations were suppressed by both cortical actin and microtubules. Surprisingly, the microtubule motor Kinesin-1 also suppressed fluctuations to a similar degree as F-actin. Kinesin-1 may mediate linkage of the microtubule (+)-ends to the actin cortex. Consistent with this model is our finding that Kinesin-1-GFP accumulates at the cortical actin caps. PMID:26331244

  9. Cross-trial correlation analysis of evoked potentials reveals arousal-related attenuation of thalamo-cortical coupling.

    PubMed

    Sobolewski, Aleksander; Kublik, Ewa; Swiejkowski, Daniel A; Lęski, Szymon; Kamiński, Jan K; Wróbel, Andrzej

    2010-12-01

    We describe a computational method for assessing functional connectivity in sensory neuronal networks. The method, which we term cross-trial correlation, can be applied to signals representing local field potentials (LFPs) evoked by sensory stimulations and utilizes their trial-to-trial variability. A set of single trial samples of a given post-stimulus latency from consecutive evoked potentials (EPs) recorded at a given site is correlated with such sets for all other latencies and recording sites. The results of this computation reveal how neuronal activities at various sites and latencies correspond to activation of other sites at other latencies. The method was used to investigate the functional connectivity of thalamo-cortical network of somatosensory system in behaving rats at two levels of alertness: habituated and aroused. We analyzed potentials evoked by vibrissal deflections recorded simultaneously from the ventrobasal thalamus and barrel cortex. The cross-trial correlation analysis applied to the early post-stimulus period (<25 ms) showed that the magnitude of the population spike recorded in the thalamus at 5 ms post-stimulus correlated with the cortical activation at 6-13 ms post-stimulus. This correlation value was reduced at 6-9 ms, i.e. at early postsynaptic cortical response, with increased level of the animals' arousal. Similarly, the aroused state diminished positive thalamo-cortical correlation for subsequent early EP waves, whereas the efficacy of an indirect cortico-fugal inhibition (over 15 ms) did not change significantly. Thus we were able to characterize the state related changes of functional connections within the thalamo-cortical network of behaving animals.

  10. Atypical case of hemiconvulsions-hemiplegia-epilepsy syndrome revealing contralateral focal cortical dysplasia.

    PubMed

    Bahi-Buisson, Nadia; Kossorotoff, Manoelle; Barnerias, Christine; Boddaert, Nathalie; Bourgeois, Marie; Dulac, Olivier; Plouin, Perrine; Chiron, Catherine; Hertz-Pannier, Lucie

    2005-12-01

    Hemiconvulsions-hemiplegia-epilepsy syndrome (HH/HHE) is a rare epileptic syndrome consisting of a prolonged unilateral convulsion producing a persisting hemiplegia, sometimes followed by epilepsy. We report on a 13-month-old male who presented with febrile left-sided HH syndrome with right hemispheric unilateral cytotoxic oedema followed by hemispheric atrophy on magnetic resonance imaging (MRI). Six months later the child progressively developed refractory focal epilepsy, including right hemiclonic seizures, and nearly continuous left frontal rhythmic spikes, suggesting the presence of a focal cortical dysplasia (FCD). A repeat MRI at 2 years of age showed left frontal FCD. This unusual case of dual pathology--right HH syndrome and left FCD--suggests that some other factor than the malformation determined the prolonged status and brain atrophy. The kinetics of regional cortical maturation could explain this unusual condition.

  11. Epigenetic profiling reveals a developmental decrease in promoter accessibility during cortical maturation in vivo.

    PubMed

    Venkatesh, Ishwariya; Simpson, Matthew T; Coley, Denise M; Blackmore, Murray G

    2016-12-01

    Axon regeneration in adult central nervous system (CNS) is limited in part by a developmental decline in the ability of injured neurons to re-express needed regeneration associated genes (RAGs). Adult CNS neurons may lack appropriate pro-regenerative transcription factors, or may display chromatin structure that restricts transcriptional access to RAGs. Here we performed epigenetic profiling around the promoter regions of key RAGs, and found progressive restriction across a time course of cortical maturation. These data identify a potential intrinsic constraint to axon growth in adult CNS neurons. Neurite outgrowth from cultured postnatal cortical neurons, however, proved insensitive to treatments that improve axon growth in other cell types, including combinatorial overexpression of AP1 factors, overexpression of histone acetyltransferases, and pharmacological inhibitors of histone deacetylases. This insensitivity could be due to intermediate chromatin closure at the time of culture, and highlights important differences in cell culture models used to test potential pro-regenerative interventions.

  12. Epigenetic profiling reveals a developmental decrease in promoter accessibility during cortical maturation in vivo

    PubMed Central

    Venkatesh, Ishwariya; Simpson, Matthew T.; Coley, Denise M.; Blackmore, Murray G.

    2016-01-01

    Axon regeneration in adult central nervous system (CNS) is limited in part by a developmental decline in the ability of injured neurons to re-express needed regeneration associated genes (RAGs). Adult CNS neurons may lack appropriate pro-regenerative transcription factors, or may display chromatin structure that restricts transcriptional access to RAGs. Here we performed epigenetic profiling around the promoter regions of key RAGs, and found progressive restriction across a time course of cortical maturation. These data identify a potential intrinsic constraint to axon growth in adult CNS neurons. Neurite outgrowth from cultured postnatal cortical neurons, however, proved insensitive to treatments that improve axon growth in other cell types, including combinatorial overexpression of AP1 factors, overexpression of histone acetyltransferases, and pharmacological inhibitors of histone deacetylases. This insensitivity could be due to intermediate chromatin closure at the time of culture, and highlights important differences in cell culture models used to test potential pro-regenerative interventions. PMID:27990351

  13. Dominant hemisphere lateralization of cortical parasympathetic control as revealed by frontotemporal dementia

    PubMed Central

    Guo, Christine C.; Sturm, Virginia E.; Zhou, Juan; Gennatas, Efstathios D.; Trujillo, Andrew J.; Hua, Alice Y.; Crawford, Richard; Stables, Lara; Kramer, Joel H.; Rankin, Katherine; Levenson, Robert W.; Rosen, Howard J.; Miller, Bruce L.; Seeley, William W.

    2016-01-01

    The brain continuously influences and perceives the physiological condition of the body. Related cortical representations have been proposed to shape emotional experience and guide behavior. Although previous studies have identified brain regions recruited during autonomic processing, neurological lesion studies have yet to delineate the regions critical for maintaining autonomic outflow. Even greater controversy surrounds hemispheric lateralization along the parasympathetic–sympathetic axis. The behavioral variant of frontotemporal dementia (bvFTD), featuring progressive and often asymmetric degeneration that includes the frontoinsular and cingulate cortices, provides a unique lesion model for elucidating brain structures that control autonomic tone. Here, we show that bvFTD is associated with reduced baseline cardiac vagal tone and that this reduction correlates with left-lateralized functional and structural frontoinsular and cingulate cortex deficits and with reduced agreeableness. Our results suggest that networked brain regions in the dominant hemisphere are critical for maintaining an adaptive level of baseline parasympathetic outflow. PMID:27071080

  14. 4D Traction Force Microscopy Reveals Asymmetric Cortical Forces in Migrating Dictyostelium Cells

    NASA Astrophysics Data System (ADS)

    Delanoë-Ayari, H.; Rieu, J. P.; Sano, M.

    2010-12-01

    We present a 4D (x; y; z; t) force map of Dictyostelium cells crawling on a soft gel substrate. Vertical forces are of the same order as the tangential ones. The cells pull the substratum upward along the cell, medium, or substratum contact line and push it downward under the cell except for the pseudopods. We demonstrate quantitatively that the variations in the asymmetry in cortical forces correlates with the variations of the direction and speed of cell displacement.

  15. Unmasking Latent Inhibitory Connections in Human Cortex to Reveal Dormant Cortical Memories

    PubMed Central

    Barron, H.C.; Vogels, T.P.; Emir, U.E.; Makin, T.R.; O’Shea, J.; Clare, S.; Jbabdi, S.; Dolan, R.J.; Behrens, T.E.J.

    2016-01-01

    Summary Balance of cortical excitation and inhibition (EI) is thought to be disrupted in several neuropsychiatric conditions, yet it is not clear how it is maintained in the healthy human brain. When EI balance is disturbed during learning and memory in animal models, it can be restabilized via formation of inhibitory replicas of newly formed excitatory connections. Here we assess evidence for such selective inhibitory rebalancing in humans. Using fMRI repetition suppression we measure newly formed cortical associations in the human brain. We show that expression of these associations reduces over time despite persistence in behavior, consistent with inhibitory rebalancing. To test this, we modulated excitation/inhibition balance with transcranial direct current stimulation (tDCS). Using ultra-high-field (7T) MRI and spectroscopy, we show that reducing GABA allows cortical associations to be re-expressed. This suggests that in humans associative memories are stored in balanced excitatory-inhibitory ensembles that lie dormant unless latent inhibitory connections are unmasked. Video Abstract PMID:26996082

  16. Early Category-Specific Cortical Activation Revealed by Visual Stimulus Inversion

    PubMed Central

    Meeren, Hanneke K. M.; Hadjikhani, Nouchine; Ahlfors, Seppo P.; Hämäläinen, Matti S.; de Gelder, Beatrice

    2008-01-01

    Visual categorization may already start within the first 100-ms after stimulus onset, in contrast with the long-held view that during this early stage all complex stimuli are processed equally and that category-specific cortical activation occurs only at later stages. The neural basis of this proposed early stage of high-level analysis is however poorly understood. To address this question we used magnetoencephalography and anatomically-constrained distributed source modeling to monitor brain activity with millisecond-resolution while subjects performed an orientation task on the upright and upside-down presented images of three different stimulus categories: faces, houses and bodies. Significant inversion effects were found for all three stimulus categories between 70–100-ms after picture onset with a highly category-specific cortical distribution. Differential responses between upright and inverted faces were found in well-established face-selective areas of the inferior occipital cortex and right fusiform gyrus. In addition, early category-specific inversion effects were found well beyond visual areas. Our results provide the first direct evidence that category-specific processing in high-level category-sensitive cortical areas already takes place within the first 100-ms of visual processing, significantly earlier than previously thought, and suggests the existence of fast category-specific neocortical routes in the human brain. PMID:18946504

  17. Cell-sized liposomes reveal how actomyosin cortical tension drives shape change.

    PubMed

    Carvalho, Kevin; Tsai, Feng-Ching; Tsai, Feng C; Lees, Edouard; Voituriez, Raphaël; Koenderink, Gijsje H; Sykes, Cecile

    2013-10-08

    Animal cells actively generate contractile stress in the actin cortex, a thin actin network beneath the cell membrane, to facilitate shape changes during processes like cytokinesis and motility. On the microscopic scale, this stress is generated by myosin molecular motors, which bind to actin cytoskeletal filaments and use chemical energy to exert pulling forces. To decipher the physical basis for the regulation of cell shape changes, here, we use a cell-like system with a cortex anchored to the outside or inside of a liposome membrane. This system enables us to dissect the interplay between motor pulling forces, cortex-membrane anchoring, and network connectivity. We show that cortices on the outside of liposomes either spontaneously rupture and relax built-up mechanical stress by peeling away around the liposome or actively compress and crush the liposome. The decision between peeling and crushing depends on the cortical tension determined by the amount of motors and also on the connectivity of the cortex and its attachment to the membrane. Membrane anchoring strongly affects the morphology of cortex contraction inside liposomes: cortices contract inward when weakly attached, whereas they contract toward the membrane when strongly attached. We propose a physical model based on a balance of active tension and mechanical resistance to rupture. Our findings show how membrane attachment and network connectivity are able to regulate actin cortex remodeling and membrane-shape changes for cell polarization.

  18. Small-world anatomical networks in the human brain revealed by cortical thickness from MRI.

    PubMed

    He, Yong; Chen, Zhang J; Evans, Alan C

    2007-10-01

    An important issue in neuroscience is the characterization for the underlying architectures of complex brain networks. However, little is known about the network of anatomical connections in the human brain. Here, we investigated large-scale anatomical connection patterns of the human cerebral cortex using cortical thickness measurements from magnetic resonance images. Two areas were considered anatomically connected if they showed statistically significant correlations in cortical thickness and we constructed the network of such connections using 124 brains from the International Consortium for Brain Mapping database. Significant short- and long-range connections were found in both intra- and interhemispheric regions, many of which were consistent with known neuroanatomical pathways measured by human diffusion imaging. More importantly, we showed that the human brain anatomical network had robust small-world properties with cohesive neighborhoods and short mean distances between regions that were insensitive to the selection of correlation thresholds. Additionally, we also found that this network and the probability of finding a connection between 2 regions for a given anatomical distance had both exponentially truncated power-law distributions. Our results demonstrated the basic organizational principles for the anatomical network in the human brain compatible with previous functional networks studies, which provides important implications of how functional brain states originate from their structural underpinnings. To our knowledge, this study provides the first report of small-world properties and degree distribution of anatomical networks in the human brain using cortical thickness measurements.

  19. Graph theory reveals hyper-functionality in visual cortices of Seasonal Affective Disorder patients.

    PubMed

    Borchardt, Viola; Krause, Anna Linda; Starck, Tuomo; Nissilä, Juuso; Timonen, Markku; Kiviniemi, Vesa; Walter, Martin

    2015-02-01

    Seasonal affective disorder (SAD) is a subtype of recurrent unipolar or bipolar depressive disorder with a higher prevalence in winter than in summer. The biological underpinnings of SAD are so far poorly understood. Studies examining SAD have found disturbances between the molecular and connectivity scales. The aim of the study was to explore changes in functional connectivity typical for SAD. We investigated unmedicated, untreated SAD patients and healthy controls using resting-state functional magnetic resonance imaging (rs-fMRI) utilizing graph theory, a data driven and hypothesis free approach, to model functional networks of the brain. Comparing whole brain network properties using graph theory we observed globally affected network topologies with increasing pathlength in SAD. Nodal changes, however, were highly restricted to bilateral inferior occipital cortex. Interestingly, we found a lateralization where hyper-connectedness was restricted to right inferior occipital cortex and hyper-efficiency was found in the left inferior occipital cortex. Furthermore, we found these nodes became more "hub like" in patients, suggesting a greater functional role. Our work stresses the importance of abnormal intrinsic processing during rest, primarily affecting visual areas and subsequently changing whole brain networks, and thus providing an important hint towards potential future therapeutic approaches.

  20. Temporal Non-Local Means Filtering Reveals Real-Time Whole-Brain Cortical Interactions in Resting fMRI.

    PubMed

    Bhushan, Chitresh; Chong, Minqi; Choi, Soyoung; Joshi, Anand A; Haldar, Justin P; Damasio, Hanna; Leahy, Richard M

    2016-01-01

    Intensity variations over time in resting BOLD fMRI exhibit spatial correlation patterns consistent with a set of large scale cortical networks. However, visualizations of this data on the brain surface, even after extensive preprocessing, are dominated by local intensity fluctuations that obscure larger scale behavior. Our novel adaptation of non-local means (NLM) filtering, which we refer to as temporal NLM or tNLM, reduces these local fluctuations without the spatial blurring that occurs when using standard linear filtering methods. We show examples of tNLM filtering that allow direct visualization of spatio-temporal behavior on the cortical surface. These results reveal patterns of activity consistent with known networks as well as more complex dynamic changes within and between these networks. This ability to directly visualize brain activity may facilitate new insights into spontaneous brain dynamics. Further, temporal NLM can also be used as a preprocessor for resting fMRI for exploration of dynamic brain networks. We demonstrate its utility through application to graph-based functional cortical parcellation. Simulations with known ground truth functional regions demonstrate that tNLM filtering prior to parcellation avoids the formation of false parcels that can arise when using linear filtering. Application to resting fMRI data from the Human Connectome Project shows significant improvement, in comparison to linear filtering, in quantitative agreement with functional regions identified independently using task-based experiments as well as in test-retest reliability.

  1. Temporal Non-Local Means Filtering Reveals Real-Time Whole-Brain Cortical Interactions in Resting fMRI

    PubMed Central

    Bhushan, Chitresh; Chong, Minqi; Choi, Soyoung; Joshi, Anand A.; Haldar, Justin P.; Damasio, Hanna; Leahy, Richard M.

    2016-01-01

    Intensity variations over time in resting BOLD fMRI exhibit spatial correlation patterns consistent with a set of large scale cortical networks. However, visualizations of this data on the brain surface, even after extensive preprocessing, are dominated by local intensity fluctuations that obscure larger scale behavior. Our novel adaptation of non-local means (NLM) filtering, which we refer to as temporal NLM or tNLM, reduces these local fluctuations without the spatial blurring that occurs when using standard linear filtering methods. We show examples of tNLM filtering that allow direct visualization of spatio-temporal behavior on the cortical surface. These results reveal patterns of activity consistent with known networks as well as more complex dynamic changes within and between these networks. This ability to directly visualize brain activity may facilitate new insights into spontaneous brain dynamics. Further, temporal NLM can also be used as a preprocessor for resting fMRI for exploration of dynamic brain networks. We demonstrate its utility through application to graph-based functional cortical parcellation. Simulations with known ground truth functional regions demonstrate that tNLM filtering prior to parcellation avoids the formation of false parcels that can arise when using linear filtering. Application to resting fMRI data from the Human Connectome Project shows significant improvement, in comparison to linear filtering, in quantitative agreement with functional regions identified independently using task-based experiments as well as in test-retest reliability. PMID:27391481

  2. Long-tailed distribution of synaptic strength reveals origin and functional roles of ongoing fluctuation in cortical circuit

    NASA Astrophysics Data System (ADS)

    Teramae, Jun-nosuke

    2016-06-01

    Neurons in the cortical circuit continuous to generate irregular spike firing with extremely low firing rate (about 1-2 Hz) even when animals neither receive any external stimuli nor they do not show any significant motor movement. The ongoing activity is often called neuronal noise because measured spike trains are often highly irregular and also spike timings are highly asynchronous among neurons. Many experiments imply that neural networks themselves must generate the noisy activity as an intrinsic property of cortical circuit. However, how a network of neurons sustains the irregular spike firings with low firing rate remains unclear. Recently, by focusing on long-tailed distribution of amplitude of synaptic connections or EPSP (Excitatory Post-Synaptic Potential), we successfully revealed that due to coexistence of a few extremely strong synaptic connections and majority of weak synapses, nonlinear dynamics of population of spiking neurons can have a nontrivial stable state that corresponding to the intrinsic ongoing fluctuation of the cortical circuit. We also found that due to the fluctuation fidelity of spike transmission between neurons are optimized. Here, we report our recent findings of the ongoing fluctuation from viewpoints of mathematical and computational side.

  3. Functional somatotopy revealed across multiple cortical regions using a model of complex motor task

    PubMed Central

    Cunningham, David A.; Machado, Andre; Yue, Guang H.; Carey, Jim R.; Plow, Ela B.

    2014-01-01

    The primary motor cortex (M1) possesses a functional somatotopic structure -representations of adjacent within-limb joints overlap to facilitate coordination while maintaining discrete centers for individuated movement. We examined whether similar organization exists across other sensorimotor cortices. Twenty-four right-handed healthy subjects underwent functional Magnetic Resonance Imaging (fMRI) while tracking complex targets with flexion/extension at right finger, elbow and ankle separately. Activation related to each joint at false discovery rate of .005 served as its representation across multiple regions. Within each region, we identified the Center of Mass (COM) for each representation, and overlap between representations of within-limb (finger and elbow) and between-limb joints (finger and ankle). Somatosensory (S1) and premotor cortices (PMC) demonstrated greater distinction of COM and minimal overlap for within- and between-limb representations. Contrarily, M1 and supplementary motor area (SMA) showed more integrative somatotopy with higher sharing for within-limb representations. Superior and inferior parietal lobule (SPL and IPL) possessed both types of structure. Some clusters exhibited extensive overlap of within- and between-limb representations, while others showed discrete COMs for within-limb representations. Our results help infer hierarchy in motor control. Areas as S1 may be associated with individuated movements, while M1 may be more integrative for coordinated motion; parietal associative regions may allow switch between both modes of control. Such hierarchy creates redundant opportunities to exploit in stroke rehabilitation. Use of complex rather than traditionally used simple movements was integral to illustrating comprehensive somatotopic structure; complex tasks can potentially help understand cortical representation of skill and learning-related plasticity. PMID:23920009

  4. Selective impairment of hippocampus and posterior hub areas in Alzheimer's disease: an MEG-based multiplex network study.

    PubMed

    Yu, Meichen; Engels, Marjolein M A; Hillebrand, Arjan; van Straaten, Elisabeth C W; Gouw, Alida A; Teunissen, Charlotte; van der Flier, Wiesje M; Scheltens, Philip; Stam, Cornelis J

    2017-03-16

    Although frequency-specific network analyses have shown that functional brain networks are altered in patients with Alzheimer's disease, the relationships between these frequency-specific network alterations remain largely unknown. Multiplex network analysis is a novel network approach to study complex systems consisting of subsystems with different types of connectivity patterns. In this study, we used magnetoencephalography to integrate five frequency-band specific brain networks in a multiplex framework. Previous structural and functional brain network studies have consistently shown that hub brain areas are selectively disrupted in Alzheimer's disease. Accordingly, we hypothesized that hub regions in the multiplex brain networks are selectively targeted in patients with Alzheimer's disease in comparison to healthy control subjects. Eyes-closed resting-state magnetoencephalography recordings from 27 patients with Alzheimer's disease (60.6 ± 5.4 years, 12 females) and 26 controls (61.8 ± 5.5 years, 14 females) were projected onto atlas-based regions of interest using beamforming. Subsequently, source-space time series for both 78 cortical and 12 subcortical regions were reconstructed in five frequency bands (delta, theta, alpha 1, alpha 2 and beta band). Multiplex brain networks were constructed by integrating frequency-specific magnetoencephalography networks. Functional connections between all pairs of regions of interests were quantified using a phase-based coupling metric, the phase lag index. Several multiplex hub and heterogeneity metrics were computed to capture both overall importance of each brain area and heterogeneity of the connectivity patterns across frequency-specific layers. Different nodal centrality metrics showed consistently that several hub regions, particularly left hippocampus, posterior parts of the default mode network and occipital regions, were vulnerable in patients with Alzheimer's disease compared to control subjects. Of note

  5. GABAergic hub neurons orchestrate synchrony in developing hippocampal networks.

    PubMed

    Bonifazi, P; Goldin, M; Picardo, M A; Jorquera, I; Cattani, A; Bianconi, G; Represa, A; Ben-Ari, Y; Cossart, R

    2009-12-04

    Brain function operates through the coordinated activation of neuronal assemblies. Graph theory predicts that scale-free topologies, which include "hubs" (superconnected nodes), are an effective design to orchestrate synchronization. Whether hubs are present in neuronal assemblies and coordinate network activity remains unknown. Using network dynamics imaging, online reconstruction of functional connectivity, and targeted whole-cell recordings in rats and mice, we found that developing hippocampal networks follow a scale-free topology, and we demonstrated the existence of functional hubs. Perturbation of a single hub influenced the entire network dynamics. Morphophysiological analysis revealed that hub cells are a subpopulation of gamma-aminobutyric acid-releasing (GABAergic) interneurons possessing widespread axonal arborizations. These findings establish a central role for GABAergic interneurons in shaping developing networks and help provide a conceptual framework for studying neuronal synchrony.

  6. Cortical network for gaze control in humans revealed using multimodal MRI.

    PubMed

    Anderson, Elaine J; Jones, Derek K; O'Gorman, Ruth L; Leemans, Alexander; Catani, Marco; Husain, Masud

    2012-04-01

    Functional magnetic resonance imaging (fMRI) techniques allow definition of cortical nodes that are presumed to be components of large-scale distributed brain networks involved in cognitive processes. However, very few investigations examine whether such functionally defined areas are in fact structurally connected. Here, we used combined fMRI and diffusion MRI-based tractography to define the cortical network involved in saccadic eye movement control in humans. The results of this multimodal imaging approach demonstrate white matter pathways connecting the frontal eye fields and supplementary eye fields, consistent with the known connectivity of these regions in macaque monkeys. Importantly, however, these connections appeared to be more prominent in the right hemisphere of humans. In addition, there was evidence of a dorsal frontoparietal pathway connecting the frontal eye field and the inferior parietal lobe, also right hemisphere dominant, consistent with specialization of the right hemisphere for directed attention in humans. These findings demonstrate the utility and potential of using multimodal imaging techniques to define large-scale distributed brain networks, including those that demonstrate known hemispheric asymmetries in humans.

  7. Long-term potentiation in freely moving rats reveals asymmetries in thalamic and cortical inputs to the lateral amygdala.

    PubMed

    Doyère, Valérie; Schafe, Glenn E; Sigurdsson, Torfi; LeDoux, Joseph E

    2003-06-01

    Long-term memory underlying Pavlovian fear conditioning is believed to involve plasticity at sensory input synapses in the lateral nucleus of the amygdala (LA). A useful physiological model for studying synaptic plasticity is long-term potentiation (LTP). LTP in the LA has been studied only in vitro or in anaesthetized rats. Here, we tested whether LTP can be induced in auditory input pathways to the LA in awake rats, and if so, whether it persists over days. In chronically implanted rats, extracellular field potentials evoked in the LA by stimulation of the auditory thalamus and the auditory association cortex, using test simulations and input/output (I/O) curves, were compared in the same animals after tetanization of either pathway alone or after combined tetanization. For both pathways, LTP was input-specific and long lasting. LTP at cortical inputs exhibited the largest change at early time points (24 h) but faded within 3 days. In contrast, LTP at thalamic inputs, though smaller initially than cortical LTP, remained stable until at least 6 days. Comparisons of I/O curves indicated that the two pathways may rely on different mechanisms for the maintenance of LTP and may benefit differently from their coactivation. This is the first report of LTP at sensory inputs to the LA in awake animals. The results reveal important characteristics of synaptic plasticity in neuronal circuits of fear memory that could not have been revealed with in vitro preparations, and suggest a differential role of thalamic and cortical auditory afferents in long-term memory of fear conditioning.

  8. The banana genome hub.

    PubMed

    Droc, Gaëtan; Larivière, Delphine; Guignon, Valentin; Yahiaoui, Nabila; This, Dominique; Garsmeur, Olivier; Dereeper, Alexis; Hamelin, Chantal; Argout, Xavier; Dufayard, Jean-François; Lengelle, Juliette; Baurens, Franc-Christophe; Cenci, Alberto; Pitollat, Bertrand; D'Hont, Angélique; Ruiz, Manuel; Rouard, Mathieu; Bocs, Stéphanie

    2013-01-01

    Banana is one of the world's favorite fruits and one of the most important crops for developing countries. The banana reference genome sequence (Musa acuminata) was recently released. Given the taxonomic position of Musa, the completed genomic sequence has particular comparative value to provide fresh insights about the evolution of the monocotyledons. The study of the banana genome has been enhanced by a number of tools and resources that allows harnessing its sequence. First, we set up essential tools such as a Community Annotation System, phylogenomics resources and metabolic pathways. Then, to support post-genomic efforts, we improved banana existing systems (e.g. web front end, query builder), we integrated available Musa data into generic systems (e.g. markers and genetic maps, synteny blocks), we have made interoperable with the banana hub, other existing systems containing Musa data (e.g. transcriptomics, rice reference genome, workflow manager) and finally, we generated new results from sequence analyses (e.g. SNP and polymorphism analysis). Several uses cases illustrate how the Banana Genome Hub can be used to study gene families. Overall, with this collaborative effort, we discuss the importance of the interoperability toward data integration between existing information systems. Database URL: http://banana-genome.cirad.fr/

  9. The Banana Genome Hub

    PubMed Central

    Droc, Gaëtan; Larivière, Delphine; Guignon, Valentin; Yahiaoui, Nabila; This, Dominique; Garsmeur, Olivier; Dereeper, Alexis; Hamelin, Chantal; Argout, Xavier; Dufayard, Jean-François; Lengelle, Juliette; Baurens, Franc-Christophe; Cenci, Alberto; Pitollat, Bertrand; D’Hont, Angélique; Ruiz, Manuel; Rouard, Mathieu; Bocs, Stéphanie

    2013-01-01

    Banana is one of the world’s favorite fruits and one of the most important crops for developing countries. The banana reference genome sequence (Musa acuminata) was recently released. Given the taxonomic position of Musa, the completed genomic sequence has particular comparative value to provide fresh insights about the evolution of the monocotyledons. The study of the banana genome has been enhanced by a number of tools and resources that allows harnessing its sequence. First, we set up essential tools such as a Community Annotation System, phylogenomics resources and metabolic pathways. Then, to support post-genomic efforts, we improved banana existing systems (e.g. web front end, query builder), we integrated available Musa data into generic systems (e.g. markers and genetic maps, synteny blocks), we have made interoperable with the banana hub, other existing systems containing Musa data (e.g. transcriptomics, rice reference genome, workflow manager) and finally, we generated new results from sequence analyses (e.g. SNP and polymorphism analysis). Several uses cases illustrate how the Banana Genome Hub can be used to study gene families. Overall, with this collaborative effort, we discuss the importance of the interoperability toward data integration between existing information systems. Database URL: http://banana-genome.cirad.fr/ PMID:23707967

  10. Positron Emission Tomography Imaging Reveals Auditory and Frontal Cortical Regions Involved with Speech Perception and Loudness Adaptation.

    PubMed

    Berding, Georg; Wilke, Florian; Rode, Thilo; Haense, Cathleen; Joseph, Gert; Meyer, Geerd J; Mamach, Martin; Lenarz, Minoo; Geworski, Lilli; Bengel, Frank M; Lenarz, Thomas; Lim, Hubert H

    2015-01-01

    Considerable progress has been made in the treatment of hearing loss with auditory implants. However, there are still many implanted patients that experience hearing deficiencies, such as limited speech understanding or vanishing perception with continuous stimulation (i.e., abnormal loudness adaptation). The present study aims to identify specific patterns of cerebral cortex activity involved with such deficiencies. We performed O-15-water positron emission tomography (PET) in patients implanted with electrodes within the cochlea, brainstem, or midbrain to investigate the pattern of cortical activation in response to speech or continuous multi-tone stimuli directly inputted into the implant processor that then delivered electrical patterns through those electrodes. Statistical parametric mapping was performed on a single subject basis. Better speech understanding was correlated with a larger extent of bilateral auditory cortex activation. In contrast to speech, the continuous multi-tone stimulus elicited mainly unilateral auditory cortical activity in which greater loudness adaptation corresponded to weaker activation and even deactivation. Interestingly, greater loudness adaptation was correlated with stronger activity within the ventral prefrontal cortex, which could be up-regulated to suppress the irrelevant or aberrant signals into the auditory cortex. The ability to detect these specific cortical patterns and differences across patients and stimuli demonstrates the potential for using PET to diagnose auditory function or dysfunction in implant patients, which in turn could guide the development of appropriate stimulation strategies for improving hearing rehabilitation. Beyond hearing restoration, our study also reveals a potential role of the frontal cortex in suppressing irrelevant or aberrant activity within the auditory cortex, and thus may be relevant for understanding and treating tinnitus.

  11. Functional magnetic resonance imaging adaptation reveals the cortical networks for processing grasp-relevant object properties.

    PubMed

    Monaco, Simona; Chen, Ying; Medendorp, W P; Crawford, J D; Fiehler, Katja; Henriques, Denise Y P

    2014-06-01

    Grasping behaviors require the selection of grasp-relevant object dimensions, independent of overall object size. Previous neuroimaging studies found that the intraparietal cortex processes object size, but it is unknown whether the graspable dimension (i.e., grasp axis between selected points on the object) or the overall size of objects triggers activation in that region. We used functional magnetic resonance imaging adaptation to investigate human brain areas involved in processing the grasp-relevant dimension of real 3-dimensional objects in grasping and viewing tasks. Trials consisted of 2 sequential stimuli in which the object's grasp-relevant dimension, its global size, or both were novel or repeated. We found that calcarine and extrastriate visual areas adapted to object size regardless of the grasp-relevant dimension during viewing tasks. In contrast, the superior parietal occipital cortex (SPOC) and lateral occipital complex of the left hemisphere adapted to the grasp-relevant dimension regardless of object size and task. Finally, the dorsal premotor cortex adapted to the grasp-relevant dimension in grasping, but not in viewing, tasks, suggesting that motor processing was complete at this stage. Taken together, our results provide a complete cortical circuit for progressive transformation of general object properties into grasp-related responses.

  12. In vivo imaging reveals that pregabalin inhibits cortical spreading depression and propagation to subcortical brain structures.

    PubMed

    Cain, Stuart M; Bohnet, Barry; LeDue, Jeffrey; Yung, Andrew C; Garcia, Esperanza; Tyson, John R; Alles, Sascha R A; Han, Huili; van den Maagdenberg, Arn M J M; Kozlowski, Piotr; MacVicar, Brian A; Snutch, Terrance P

    2017-02-28

    Migraine is characterized by severe headaches that can be preceded by an aura likely caused by cortical spreading depression (SD). The antiepileptic pregabalin (Lyrica) shows clinical promise for migraine therapy, although its efficacy and mechanism of action are unclear. As detected by diffusion-weighted MRI (DW-MRI) in wild-type (WT) mice, the acute systemic administration of pregabalin increased the threshold for SD initiation in vivo. In familial hemiplegic migraine type 1 mutant mice expressing human mutations (R192Q and S218L) in the CaV2.1 (P/Q-type) calcium channel subunit, pregabalin slowed the speed of SD propagation in vivo. Acute systemic administration of pregabalin in vivo also selectively prevented the migration of SD into subcortical striatal and hippocampal regions in the R192Q strain that exhibits a milder phenotype and gain of CaV2.1 channel function. At the cellular level, pregabalin inhibited glutamatergic synaptic transmission differentially in WT, R192Q, and S218L mice. The study describes a DW-MRI analysis method for tracking the progression of SD and provides support and a mechanism of action for pregabalin as a possible effective therapy in the treatment of migraine.

  13. Brain-wide Maps Reveal Stereotyped Cell-Type-Based Cortical Architecture and Subcortical Sexual Dimorphism.

    PubMed

    Kim, Yongsoo; Yang, Guangyu Robert; Pradhan, Kith; Venkataraju, Kannan Umadevi; Bota, Mihail; García Del Molino, Luis Carlos; Fitzgerald, Greg; Ram, Keerthi; He, Miao; Levine, Jesse Maurica; Mitra, Partha; Huang, Z Josh; Wang, Xiao-Jing; Osten, Pavel

    2017-10-05

    The stereotyped features of neuronal circuits are those most likely to explain the remarkable capacity of the brain to process information and govern behaviors, yet it has not been possible to comprehensively quantify neuronal distributions across animals or genders due to the size and complexity of the mammalian brain. Here we apply our quantitative brain-wide (qBrain) mapping platform to document the stereotyped distributions of mainly inhibitory cell types. We discover an unexpected cortical organizing principle: sensory-motor areas are dominated by output-modulating parvalbumin-positive interneurons, whereas association, including frontal, areas are dominated by input-modulating somatostatin-positive interneurons. Furthermore, we identify local cell type distributions with more cells in the female brain in 10 out of 11 sexually dimorphic subcortical areas, in contrast to the overall larger brains in males. The qBrain resource can be further mined to link stereotyped aspects of neuronal distributions to known and unknown functions of diverse brain regions. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Functional Near-Infrared Spectroscopy Reveals Reduced Interhemispheric Cortical Communication after Pediatric Concussion

    PubMed Central

    Urban, Karolina J.; Barlow, Karen M.; Jimenez, Jon J.; Goodyear, Bradley G.

    2015-01-01

    Abstract Concussion, or mild traumatic brain injury (mTBI), is a growing concern, especially among the pediatric population. By age 25, as many as 30% of the population are likely to have had a concussion. Many result in long-term disability, with some evolving to postconcussion syndrome. Treatments are being developed, but are difficult to assess given the lack of measures to quantitatively monitor concussion. There is no accepted quantitative imaging metric for monitoring concussion. We hypothesized that because cognitive function and fiber tracks are often impacted in concussion, interhemispheric brain communication may be impaired. We used functional near-infrared spectroscopy (fNIRS) to quantify functional coherence between the left and right motor cortex as a marker of interhemispheric communication. Studies were undertaken during the resting state and with a finger-tapping task to activate the motor cortex. Pediatric patients (ages 12–18) had symptoms for 31–473 days, compared to controls, who have not had reported a previous concussion. We detected differences between patients and controls in coherence between the contralateral motor cortices using measurements of total hemoglobin and oxy-hemoglobin with a p<0.01 (n=8, control; n=12 mTBI). Given the critical need for a quantitative biomarker for recovery after a concussion, we present these data to highlight the potential of fNIRS coupled with interhemispheric coherence analysis as a biomarker of concussion injury. PMID:25387354

  15. In vivo imaging reveals that pregabalin inhibits cortical spreading depression and propagation to subcortical brain structures

    PubMed Central

    Cain, Stuart M.; Bohnet, Barry; LeDue, Jeffrey; Yung, Andrew C.; Garcia, Esperanza; Tyson, John R.; Alles, Sascha R. A.; Han, Huili; van den Maagdenberg, Arn M. J. M.; Kozlowski, Piotr; MacVicar, Brian A.; Snutch, Terrance P.

    2017-01-01

    Migraine is characterized by severe headaches that can be preceded by an aura likely caused by cortical spreading depression (SD). The antiepileptic pregabalin (Lyrica) shows clinical promise for migraine therapy, although its efficacy and mechanism of action are unclear. As detected by diffusion-weighted MRI (DW-MRI) in wild-type (WT) mice, the acute systemic administration of pregabalin increased the threshold for SD initiation in vivo. In familial hemiplegic migraine type 1 mutant mice expressing human mutations (R192Q and S218L) in the CaV2.1 (P/Q-type) calcium channel subunit, pregabalin slowed the speed of SD propagation in vivo. Acute systemic administration of pregabalin in vivo also selectively prevented the migration of SD into subcortical striatal and hippocampal regions in the R192Q strain that exhibits a milder phenotype and gain of CaV2.1 channel function. At the cellular level, pregabalin inhibited glutamatergic synaptic transmission differentially in WT, R192Q, and S218L mice. The study describes a DW-MRI analysis method for tracking the progression of SD and provides support and a mechanism of action for pregabalin as a possible effective therapy in the treatment of migraine. PMID:28223480

  16. Functional near-infrared spectroscopy reveals reduced interhemispheric cortical communication after pediatric concussion.

    PubMed

    Urban, Karolina J; Barlow, Karen M; Jimenez, Jon J; Goodyear, Bradley G; Dunn, Jeff F

    2015-06-01

    Concussion, or mild traumatic brain injury (mTBI), is a growing concern, especially among the pediatric population. By age 25, as many as 30% of the population are likely to have had a concussion. Many result in long-term disability, with some evolving to postconcussion syndrome. Treatments are being developed, but are difficult to assess given the lack of measures to quantitatively monitor concussion. There is no accepted quantitative imaging metric for monitoring concussion. We hypothesized that because cognitive function and fiber tracks are often impacted in concussion, interhemispheric brain communication may be impaired. We used functional near-infrared spectroscopy (fNIRS) to quantify functional coherence between the left and right motor cortex as a marker of interhemispheric communication. Studies were undertaken during the resting state and with a finger-tapping task to activate the motor cortex. Pediatric patients (ages 12-18) had symptoms for 31-473 days, compared to controls, who have not had reported a previous concussion. We detected differences between patients and controls in coherence between the contralateral motor cortices using measurements of total hemoglobin and oxy-hemoglobin with a p<0.01 (n=8, control; n=12 mTBI). Given the critical need for a quantitative biomarker for recovery after a concussion, we present these data to highlight the potential of fNIRS coupled with interhemispheric coherence analysis as a biomarker of concussion injury.

  17. Multiple bases of human intelligence revealed by cortical thickness and neural activation.

    PubMed

    Choi, Yu Yong; Shamosh, Noah A; Cho, Sun Hee; DeYoung, Colin G; Lee, Min Joo; Lee, Jong-Min; Kim, Sun I; Cho, Zang-Hee; Kim, Kyungjin; Gray, Jeremy R; Lee, Kun Ho

    2008-10-08

    We hypothesized that individual differences in intelligence (Spearman's g) are supported by multiple brain regions, and in particular that fluid (gF) and crystallized (gC) components of intelligence are related to brain function and structure with a distinct profile of association across brain regions. In 225 healthy young adults scanned with structural and functional magnetic resonance imaging sequences, regions of interest (ROIs) were defined on the basis of a correlation between g and either brain structure or brain function. In these ROIs, gC was more strongly related to structure (cortical thickness) than function, whereas gF was more strongly related to function (blood oxygenation level-dependent signal during reasoning) than structure. We further validated this finding by generating a neurometric prediction model of intelligence quotient (IQ) that explained 50% of variance in IQ in an independent sample. The data compel a nuanced view of the neurobiology of intelligence, providing the most persuasive evidence to date for theories emphasizing multiple distributed brain regions differing in function.

  18. Multiple-Localization and Hub Proteins

    PubMed Central

    Ota, Motonori; Gonja, Hideki; Koike, Ryotaro; Fukuchi, Satoshi

    2016-01-01

    Protein-protein interactions are fundamental for all biological phenomena, and protein-protein interaction networks provide a global view of the interactions. The hub proteins, with many interaction partners, play vital roles in the networks. We investigated the subcellular localizations of proteins in the human network, and found that the ones localized in multiple subcellular compartments, especially the nucleus/cytoplasm proteins (NCP), the cytoplasm/cell membrane proteins (CMP), and the nucleus/cytoplasm/cell membrane proteins (NCMP), tend to be hubs. Examinations of keywords suggested that among NCP, those related to post-translational modifications and transcription functions are the major contributors to the large number of interactions. These types of proteins are characterized by a multi-domain architecture and intrinsic disorder. A survey of the typical hub proteins with prominent numbers of interaction partners in the type revealed that most are either transcription factors or co-regulators involved in signaling pathways. They translocate from the cytoplasm to the nucleus, triggered by the phosphorylation and/or ubiquitination of intrinsically disordered regions. Among CMP and NCMP, the contributors to the numerous interactions are related to either kinase or ubiquitin ligase activity. Many of them reside on the cytoplasmic side of the cell membrane, and act as the upstream regulators of signaling pathways. Overall, these hub proteins function to transfer external signals to the nucleus, through the cell membrane and the cytoplasm. Our analysis suggests that multiple-localization is a crucial concept to characterize groups of hub proteins and their biological functions in cellular information processing. PMID:27285823

  19. Direction-specific fMRI adaptation reveals the visual cortical network underlying the "Rotating Snakes" illusion.

    PubMed

    Ashida, Hiroshi; Kuriki, Ichiro; Murakami, Ikuya; Hisakata, Rumi; Kitaoka, Akiyoshi

    2012-07-16

    The "Rotating Snakes" figure elicits a clear sense of anomalous motion in stationary repetitive patterns. We used an event-related fMRI adaptation paradigm to investigate cortical mechanisms underlying the illusory motion. Following an adapting stimulus (S1) and a blank period, a probe stimulus (S2) that elicited illusory motion either in the same or in the opposite direction was presented. Attention was controlled by a fixation task, and control experiments precluded explanations in terms of artefacts of local adaptation, afterimages, or involuntary eye movements. Recorded BOLD responses were smaller for S2 in the same direction than S2 in the opposite direction in V1-V4, V3A, and MT+, indicating direction-selective adaptation. Adaptation in MT+ was correlated with adaptation in V1 but not in V4. With possible downstream inheritance of adaptation, it is most likely that adaptation predominantly occurred in V1. The results extend our previous findings of activation in MT+ (I. Kuriki, H. Ashida, I. Murakami, and A. Kitaoka, 2008), revealing the activity of the cortical network for motion processing from V1 towards MT+. This provides evidence for the role of front-end motion detectors, which has been assumed in proposed models of the illusion. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Neuron-specific stimulus masking reveals interference in spike timing at the cortical level.

    PubMed

    Larson, Eric; Maddox, Ross K; Perrone, Ben P; Sen, Kamal; Billimoria, Cyrus P

    2012-02-01

    The auditory system is capable of robust recognition of sounds in the presence of competing maskers (e.g., other voices or background music). This capability arises despite the fact that masking stimuli can disrupt neural responses at the cortical level. Since the origins of such interference effects remain unknown, in this study, we work to identify and quantify neural interference effects that originate due to masking occurring within and outside receptive fields of neurons. We record from single and multi-unit auditory sites from field L, the auditory cortex homologue in zebra finches. We use a novel method called spike timing-based stimulus filtering that uses the measured response of each neuron to create an individualized stimulus set. In contrast to previous adaptive experimental approaches, which have typically focused on the average firing rate, this method uses the complete pattern of neural responses, including spike timing information, in the calculation of the receptive field. When we generate and present novel stimuli for each neuron that mask the regions within the receptive field, we find that the time-varying information in the neural responses is disrupted, degrading neural discrimination performance and decreasing spike timing reliability and sparseness. We also find that, while removing stimulus energy from frequency regions outside the receptive field does not significantly affect neural responses for many sites, adding a masker in these frequency regions can nonetheless have a significant impact on neural responses and discriminability without a significant change in the average firing rate. These findings suggest that maskers can interfere with neural responses by disrupting stimulus timing information with power either within or outside the receptive fields of neurons.

  1. Transcranial magnetic stimulation reveals two cortical pathways for visual body processing.

    PubMed

    Urgesi, Cosimo; Calvo-Merino, Beatriz; Haggard, Patrick; Aglioti, Salvatore M

    2007-07-25

    Visual recognition of human bodies is more difficult for upside down than upright presentations. This body inversion effect implies that body perception relies on configural rather than local processing. Although neuroimaging studies indicate that the visual processing of human bodies engages a large fronto-temporo-parietal network, information about the neural underpinnings of configural body processing is meager. Here, we used repetitive transcranial magnetic stimulation (rTMS) to study the causal role of premotor, visual, and parietal areas in configural processing of human bodies. Eighteen participants performed a delayed matching-to-sample task with upright or inverted static body postures. Event-related, dual-pulse rTMS was applied 150 ms after the sample stimulus onset, over left ventral premotor cortex (vPMc), right extrastriate body area (EBA), and right superior parietal lobe (SPL) and, as a control site, over the right primary visual cortex (V1). Interfering stimulation of vPMc significantly reduced accuracy of matching judgments for upright bodies. In contrast, EBA rTMS significantly reduced accuracy for inverted but not for upright bodies. Furthermore, a significant body inversion effect was observed after interfering stimulation of EBA and V1 but not of vPMc and SPL. These results demonstrate an active contribution of the fronto-parietal mirror network to configural processing of bodies and suggest a novel, embodied aspect of visual perception. In contrast, the local processing of the body, possibly based on the form of individual body parts instead of on the whole body unit, appears to depend on EBA. Therefore, we propose two distinct cortical routes for the visual processing of human bodies.

  2. Combined structural and functional imaging reveals cortical deactivations in grapheme-color synaesthesia

    PubMed Central

    O'Hanlon, Erik; Newell, Fiona N.; Mitchell, Kevin J.

    2013-01-01

    Synaesthesia is a heritable condition in which particular stimuli generate specific and consistent sensory percepts or associations in another modality or processing stream. Functional neuroimaging studies have identified potential correlates of these experiences, including, in some but not all cases, the hyperactivation of visuotemporal areas and of parietal areas thought to be involved in perceptual binding. Structural studies have identified a similarly variable spectrum of differences between synaesthetes and controls. However, it remains unclear the extent to which these neural correlates reflect the synaesthetic experience itself or additional phenotypes associated with the condition. Here, we acquired both structural and functional neuroimaging data comparing thirteen grapheme-color synaesthetes with eleven non-synaesthetes. Using voxel-based morphometry and diffusion tensor imaging, we identify a number of clusters of increased volume of gray matter, of white matter or of increased fractional anisotropy in synaesthetes vs. controls. To assess the possible involvement of these areas in the synaesthetic experience, we used nine areas of increased gray matter volume as regions of interest in an fMRI experiment that characterized the contrast in response to stimuli which induced synaesthesia (i.e., letters) vs. those which did not (non-meaningful symbols). Four of these areas showed sensitivity to this contrast in synaesthetes but not controls. Unexpectedly, in two of them, in left lateral occipital cortex and in postcentral gyrus, the letter stimuli produced a strong negative BOLD signal in synaesthetes. An additional whole-brain fMRI analysis identified 14 areas, three of which were driven mainly by a negative BOLD response to letters in synaesthetes. Our findings suggest that cortical deactivations may be involved in the conscious experience of internally generated synaesthetic percepts. PMID:24198794

  3. Comparison of deep neural networks to spatio-temporal cortical dynamics of human visual object recognition reveals hierarchical correspondence

    PubMed Central

    Cichy, Radoslaw Martin; Khosla, Aditya; Pantazis, Dimitrios; Torralba, Antonio; Oliva, Aude

    2016-01-01

    The complex multi-stage architecture of cortical visual pathways provides the neural basis for efficient visual object recognition in humans. However, the stage-wise computations therein remain poorly understood. Here, we compared temporal (magnetoencephalography) and spatial (functional MRI) visual brain representations with representations in an artificial deep neural network (DNN) tuned to the statistics of real-world visual recognition. We showed that the DNN captured the stages of human visual processing in both time and space from early visual areas towards the dorsal and ventral streams. Further investigation of crucial DNN parameters revealed that while model architecture was important, training on real-world categorization was necessary to enforce spatio-temporal hierarchical relationships with the brain. Together our results provide an algorithmically informed view on the spatio-temporal dynamics of visual object recognition in the human visual brain. PMID:27282108

  4. Comparison of deep neural networks to spatio-temporal cortical dynamics of human visual object recognition reveals hierarchical correspondence.

    PubMed

    Cichy, Radoslaw Martin; Khosla, Aditya; Pantazis, Dimitrios; Torralba, Antonio; Oliva, Aude

    2016-06-10

    The complex multi-stage architecture of cortical visual pathways provides the neural basis for efficient visual object recognition in humans. However, the stage-wise computations therein remain poorly understood. Here, we compared temporal (magnetoencephalography) and spatial (functional MRI) visual brain representations with representations in an artificial deep neural network (DNN) tuned to the statistics of real-world visual recognition. We showed that the DNN captured the stages of human visual processing in both time and space from early visual areas towards the dorsal and ventral streams. Further investigation of crucial DNN parameters revealed that while model architecture was important, training on real-world categorization was necessary to enforce spatio-temporal hierarchical relationships with the brain. Together our results provide an algorithmically informed view on the spatio-temporal dynamics of visual object recognition in the human visual brain.

  5. Soft hub for bearingless rotors

    NASA Technical Reports Server (NTRS)

    Dixon, Peter G. C.

    1991-01-01

    Soft hub concepts which allow the direct replacement of articulated rotor systems by bearingless types without any change in controllability or need for reinforcement to the drive shaft and/or transmission/fuselage attachments of the helicopter were studied. Two concepts were analyzed and confirmed for functional and structural feasibility against a design criteria and specifications established for this effort. Both systems are gimballed about a thrust carrying universal elastomeric bearing. One concept includes a set of composite flexures for drive torque transmittal from the shaft to the rotor, and another set (which is changeable) to impart hub tilting stiffness to the rotor system as required to meet the helicopter application. The second concept uses a composite bellows flexure to drive the rotor and to augment the hub stiffness provided by the elastomeric bearing. Each concept was assessed for weight, drag, ROM cost, and number of parts and compared with the production BO-105 hub.

  6. The hubs of the human connectome are generally implicated in the anatomy of brain disorders.

    PubMed

    Crossley, Nicolas A; Mechelli, Andrea; Scott, Jessica; Carletti, Francesco; Fox, Peter T; McGuire, Philip; Bullmore, Edward T

    2014-08-01

    Brain networks or 'connectomes' include a minority of highly connected hub nodes that are functionally valuable, because their topological centrality supports integrative processing and adaptive behaviours. Recent studies also suggest that hubs have higher metabolic demands and longer-distance connections than other brain regions, and therefore could be considered biologically costly. Assuming that hubs thus normally combine both high topological value and high biological cost, we predicted that pathological brain lesions would be concentrated in hub regions. To test this general hypothesis, we first identified the hubs of brain anatomical networks estimated from diffusion tensor imaging data on healthy volunteers (n = 56), and showed that computational attacks targeted on hubs disproportionally degraded the efficiency of brain networks compared to random attacks. We then prepared grey matter lesion maps, based on meta-analyses of published magnetic resonance imaging data on more than 20 000 subjects and 26 different brain disorders. Magnetic resonance imaging lesions that were common across all brain disorders were more likely to be located in hubs of the normal brain connectome (P < 10(-4), permutation test). Specifically, nine brain disorders had lesions that were significantly more likely to be located in hubs (P < 0.05, permutation test), including schizophrenia and Alzheimer's disease. Both these disorders had significantly hub-concentrated lesion distributions, although (almost completely) distinct subsets of cortical hubs were lesioned in each disorder: temporal lobe hubs specifically were associated with higher lesion probability in Alzheimer's disease, whereas in schizophrenia lesions were concentrated in both frontal and temporal cortical hubs. These results linking pathological lesions to the topological centrality of nodes in the normal diffusion tensor imaging connectome were generally replicated when hubs were defined instead by the meta-analysis of

  7. The hubs of the human connectome are generally implicated in the anatomy of brain disorders

    PubMed Central

    Mechelli, Andrea; Scott, Jessica; Carletti, Francesco; Fox, Peter T.; McGuire, Philip; Bullmore, Edward T.

    2014-01-01

    Brain networks or ‘connectomes’ include a minority of highly connected hub nodes that are functionally valuable, because their topological centrality supports integrative processing and adaptive behaviours. Recent studies also suggest that hubs have higher metabolic demands and longer-distance connections than other brain regions, and therefore could be considered biologically costly. Assuming that hubs thus normally combine both high topological value and high biological cost, we predicted that pathological brain lesions would be concentrated in hub regions. To test this general hypothesis, we first identified the hubs of brain anatomical networks estimated from diffusion tensor imaging data on healthy volunteers (n = 56), and showed that computational attacks targeted on hubs disproportionally degraded the efficiency of brain networks compared to random attacks. We then prepared grey matter lesion maps, based on meta-analyses of published magnetic resonance imaging data on more than 20 000 subjects and 26 different brain disorders. Magnetic resonance imaging lesions that were common across all brain disorders were more likely to be located in hubs of the normal brain connectome (P < 10−4, permutation test). Specifically, nine brain disorders had lesions that were significantly more likely to be located in hubs (P < 0.05, permutation test), including schizophrenia and Alzheimer’s disease. Both these disorders had significantly hub-concentrated lesion distributions, although (almost completely) distinct subsets of cortical hubs were lesioned in each disorder: temporal lobe hubs specifically were associated with higher lesion probability in Alzheimer’s disease, whereas in schizophrenia lesions were concentrated in both frontal and temporal cortical hubs. These results linking pathological lesions to the topological centrality of nodes in the normal diffusion tensor imaging connectome were generally replicated when hubs were defined instead by the meta

  8. USDA Southwest climate hub for climate change

    USDA-ARS?s Scientific Manuscript database

    The USDA Southwest (SW) Climate Hub was created in February 2014 to develop risk adaptation and mitigation strategies for coping with climate change effects on agricultural productivity. There are seven regional hubs across the country with three subsidiary hubs. The SW Climate Hub Region is made up...

  9. Layer-specific gene expression in epileptogenic type II focal cortical dysplasia: normal-looking neurons reveal the presence of a hidden laminar organization

    PubMed Central

    2014-01-01

    Background Type II focal cortical dysplasias (FCDs) are malformations of cortical development characterised by the disorganisation of the normal neocortical structure and the presence of dysmorphic neurons (DNs) and balloon cells (BCs). The pathogenesis of FCDs has not yet been clearly established, although a number of histopathological patterns and molecular findings suggest that they may be due to abnormal neuronal and glial proliferation and migration processes. In order to gain further insights into cortical layering disruption and investigate the origin of DNs and BCs, we used in situ RNA hybridisation of human surgical specimens with a neuropathologically definite diagnosis of Type IIa/b FCD and a panel of layer-specific genes (LSGs) whose expression covers all cortical layers. We also used anti-phospho-S6 ribosomal protein antibody to investigate mTOR pathway hyperactivation. Results LSGs were expressed in both normal and abnormal cells (BCs and DNs) but their distribution was different. Normal-looking neurons, which were visibly reduced in the core of the lesion, were apparently located in the appropriate cortical laminae thus indicating a partial laminar organisation. On the contrary, DNs and BCs, labelled with anti-phospho-S6 ribosomal protein antibody, were spread throughout the cortex without any apparent rule and showed a highly variable LSG expression pattern. Moreover, LSGs did not reveal any differences between Type IIa and IIb FCD. Conclusion These findings suggest the existence of hidden cortical lamination involving normal-looking neurons, which retain their ability to migrate correctly in the cortex, unlike DNs which, in addition to their morphological abnormalities and mTOR hyperactivation, show an altered migratory pattern. Taken together these data suggest that an external or environmental hit affecting selected precursor cells during the very early stages of cortical development may disrupt normal cortical development. PMID:24735483

  10. Anticipatory planning reveals segmentation of cortical motor output during action observation.

    PubMed

    Janssen, Loes; Steenbergen, Bert; Carson, Richard G

    2015-01-01

    It has been argued that the variation in brain activity that occurs when observing another person reflects a representation of actions that is indivisible, and which plays out in full once the intent of the actor can be discerned. We used transcranial magnetic stimulation to probe the excitability of corticospinal projections to 2 intrinsic hand muscles while motions to reach and grasp an object were observed. A symbolic cue either faithfully indicated the required final orientation of the object and thus the nature of the grasp that was required, or was in conflict with the movement subsequently displayed. When the cue was veridical, modulation of excitability was in accordance with the functional role of the muscles in the action observed. If however the cue had indicated that the alternative grasp would be required, modulation of output to first dorsal interosseus was consistent with the action specified, rather than the action observed--until the terminal phase of the motion sequence during which the object was seen lifted. Modulation of corticospinal output during observation is thus segmented--it progresses initially in accordance with the action anticipated, and if discrepancies are revealed by visual input, coincides thereafter with that of the action seen. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  11. Electrocorticography reveals the temporal dynamics of posterior parietal cortical activity during recognition memory decisions

    PubMed Central

    Gonzalez, Alex; Hutchinson, J. Benjamin; Uncapher, Melina R.; Chen, Janice; LaRocque, Karen F.; Foster, Brett L.; Rangarajan, Vinitha; Parvizi, Josef; Wagner, Anthony D.

    2015-01-01

    Theories of the neurobiology of episodic memory predominantly focus on the contributions of medial temporal lobe structures, based on extensive lesion, electrophysiological, and imaging evidence. Against this backdrop, functional neuroimaging data have unexpectedly implicated left posterior parietal cortex (PPC) in episodic retrieval, revealing distinct activation patterns in PPC subregions as humans make memory-related decisions. To date, theorizing about the functional contributions of PPC has been hampered by the absence of information about the temporal dynamics of PPC activity as retrieval unfolds. Here, we leveraged electrocorticography to examine the temporal profile of high gamma power (HGP) in dorsal PPC subregions as participants made old/new recognition memory decisions. A double dissociation in memory-related HGP was observed, with activity in left intraparietal sulcus (IPS) and left superior parietal lobule (SPL) differing in time and sign for recognized old items (Hits) and correctly rejected novel items (CRs). Specifically, HGP in left IPS increased for Hits 300–700 ms poststimulus onset, and decayed to baseline ∼200 ms preresponse. By contrast, HGP in left SPL increased for CRs early after stimulus onset (200−300 ms) and late in the memory decision (from 700 ms to response). These memory-related effects were unique to left PPC, as they were not observed in right PPC. Finally, memory-related HGP in left IPS and SPL was sufficiently reliable to enable brain-based decoding of the participant’s memory state at the single-trial level, using multivariate pattern classification. Collectively, these data provide insights into left PPC temporal dynamics as humans make recognition memory decisions. PMID:26283375

  12. Simultaneous EEG and fMRI reveals a causally connected subcortical-cortical network during reward anticipation.

    PubMed

    Plichta, Michael M; Wolf, Isabella; Hohmann, Sarah; Baumeister, Sarah; Boecker, Regina; Schwarz, Adam J; Zangl, Maria; Mier, Daniela; Diener, Carsten; Meyer, Patric; Holz, Nathalie; Ruf, Matthias; Gerchen, Martin F; Bernal-Casas, David; Kolev, Vasil; Yordanova, Juliana; Flor, Herta; Laucht, Manfred; Banaschewski, Tobias; Kirsch, Peter; Meyer-Lindenberg, Andreas; Brandeis, Daniel

    2013-09-04

    Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) have been used to study the neural correlates of reward anticipation, but the interrelation of EEG and fMRI measures remains unknown. The goal of the present study was to investigate this relationship in response to a well established reward anticipation paradigm using simultaneous EEG-fMRI recording in healthy human subjects. Analysis of causal interactions between the thalamus (THAL), ventral-striatum (VS), and supplementary motor area (SMA), using both mediator analysis and dynamic causal modeling, revealed that (1) THAL fMRI blood oxygenation level-dependent (BOLD) activity is mediating intermodal correlations between the EEG contingent negative variation (CNV) signal and the fMRI BOLD signal in SMA and VS, (2) the underlying causal connectivity network consists of top-down regulation from SMA to VS and SMA to THAL along with an excitatory information flow through a THAL→VS→SMA route during reward anticipation, and (3) the EEG CNV signal is best predicted by a combination of THAL fMRI BOLD response and strength of top-down regulation from SMA to VS and SMA to THAL. Collectively, these findings represent a likely neurobiological mechanism mapping a primarily subcortical process, i.e., reward anticipation, onto a cortical signature.

  13. Color-Doppler sonographic tissue perfusion measurements reveal significantly diminished renal cortical perfusion in kidneys with vesicoureteral reflux

    PubMed Central

    Scholbach, T. M.; Sachse, C.

    2016-01-01

    Vesicoureteral reflux (VUR) and its sequelae may lead to reduced renal perfusion and loss of renal function. Methods to describe and monitor tissue perfusion are needed. We investigated dynamic tissue perfusion measurement (DTPM) with the PixelFlux-software to measure microvascular changes in the renal cortex in 35 children with VUR and 28 healthy children. DTPM of defined horizontal slices of the renal cortex was carried out. A kidney was assigned to the “low grade reflux”-group if the reflux grade of the voiding cystourethrogram was 1 to 3 and to the “high grade reflux”-group if the reflux grade was 4 to 5. Kidneys with VUR showed a significantly reduced cortical perfusion. Compared to healthy kidneys, this decline reached in low and high grade refluxes within the proximal 50% of the cortex: 3% and 12 %, in the distal 50% of the cortex: 21% and 44 % and in the most distal 20 % of the cortex 41% and 44%. DTPM reveals a perfusion loss in kidneys depending on the degree of VUR, which is most pronounced in the peripheral cortex. Thus, DTPM offers the tool to evaluate microvascular perfusion, to help planning treatment decisions in children with VUR. PMID:27051133

  14. Attention-dependent modulation of cortical taste circuits revealed by Granger causality with signal-dependent noise.

    PubMed

    Luo, Qiang; Ge, Tian; Grabenhorst, Fabian; Feng, Jianfeng; Rolls, Edmund T

    2013-10-01

    We show, for the first time, that in cortical areas, for example the insular, orbitofrontal, and lateral prefrontal cortex, there is signal-dependent noise in the fMRI blood-oxygen level dependent (BOLD) time series, with the variance of the noise increasing approximately linearly with the square of the signal. Classical Granger causal models are based on autoregressive models with time invariant covariance structure, and thus do not take this signal-dependent noise into account. To address this limitation, here we describe a Granger causal model with signal-dependent noise, and a novel, likelihood ratio test for causal inferences. We apply this approach to the data from an fMRI study to investigate the source of the top-down attentional control of taste intensity and taste pleasantness processing. The Granger causality with signal-dependent noise analysis reveals effects not identified by classical Granger causal analysis. In particular, there is a top-down effect from the posterior lateral prefrontal cortex to the insular taste cortex during attention to intensity but not to pleasantness, and there is a top-down effect from the anterior and posterior lateral prefrontal cortex to the orbitofrontal cortex during attention to pleasantness but not to intensity. In addition, there is stronger forward effective connectivity from the insular taste cortex to the orbitofrontal cortex during attention to pleasantness than during attention to intensity. These findings indicate the importance of explicitly modeling signal-dependent noise in functional neuroimaging, and reveal some of the processes involved in a biased activation theory of selective attention.

  15. Novel and Robust Transplantation Reveals the Acquisition of Polarized Processes by Cortical Cells Derived from Mouse and Human Pluripotent Stem Cells

    PubMed Central

    Nagashima, Fumiaki; Suzuki, Ikuo K.; Shitamukai, Atsunori; Sakaguchi, Haruko; Iwashita, Misato; Kobayashi, Taeko; Tone, Shigenobu; Toida, Kazunori; Vanderhaeghen, Pierre

    2014-01-01

    Current stem cell technologies have enabled the induction of cortical progenitors and neurons from embryonic stem cells (ESCs) and induced pluripotent stem cells in vitro. To understand the mechanisms underlying the acquisition of apico-basal polarity and the formation of processes associated with the stemness of cortical cells generated in monolayer culture, here, we developed a novel in utero transplantation system based on the moderate dissociation of adherens junctions in neuroepithelial tissue. This method enables (1) the incorporation of remarkably higher numbers of grafted cells and (2) quantitative morphological analyses at single-cell resolution, including time-lapse recording analyses. We then grafted cortical progenitors induced from mouse ESCs into the developing brain. Importantly, we revealed that the mode of process extension depends on the extrinsic apico-basal polarity of the host epithelial tissue, as well as on the intrinsic differentiation state of the grafted cells. Further, we successfully transplanted cortical progenitors induced from human ESCs, showing that our strategy enables investigation of the neurogenesis of human neural progenitors within the developing mouse cortex. Specifically, human cortical cells exhibit multiple features of radial migration. The robust transplantation method established here could be utilized both to uncover the missing gap between neurogenesis from ESCs and the tissue environment and as an in vivo model of normal and pathological human corticogenesis. PMID:24325299

  16. Cobtorin target analysis reveals that pectin functions in the deposition of cellulose microfibrils in parallel with cortical microtubules.

    PubMed

    Yoneda, Arata; Ito, Takuya; Higaki, Takumi; Kutsuna, Natsumaro; Saito, Tamio; Ishimizu, Takeshi; Osada, Hiroyuki; Hasezawa, Seiichiro; Matsui, Minami; Demura, Taku

    2010-11-01

    Cellulose and pectin are major components of primary cell walls in plants, and it is believed that their mechanical properties are important for cell morphogenesis. It has been hypothesized that cortical microtubules guide the movement of cellulose microfibril synthase in a direction parallel with the microtubules, but the mechanism by which this alignment occurs remains unclear. We have previously identified cobtorin as an inhibitor that perturbs the parallel relationship between cortical microtubules and nascent cellulose microfibrils. In this study, we searched for the protein target of cobtorin, and we found that overexpression of pectin methylesterase and polygalacturonase suppressed the cobtorin-induced cell-swelling phenotype. Furthermore, treatment with polygalacturonase restored the deposition of cellulose microfibrils in the direction parallel with cortical microtubules, and cobtorin perturbed the distribution of methylated pectin. These results suggest that control over the properties of pectin is important for the deposition of cellulose microfibrils and/or the maintenance of their orientation parallel with the cortical microtubules.

  17. Transcriptomic and anatomic parcellation of 5-HT3AR expressing cortical interneuron subtypes revealed by single-cell RNA sequencing

    PubMed Central

    Frazer, Sarah; Prados, Julien; Niquille, Mathieu; Cadilhac, Christelle; Markopoulos, Foivos; Gomez, Lucia; Tomasello, Ugo; Telley, Ludovic; Holtmaat, Anthony; Jabaudon, Denis; Dayer, Alexandre

    2017-01-01

    Cortical GABAergic interneurons constitute a highly diverse population of inhibitory neurons that are key regulators of cortical microcircuit function. An important and heterogeneous group of cortical interneurons specifically expresses the serotonin receptor 3A (5-HT3AR) but how this diversity emerges during development is poorly understood. Here we use single-cell transcriptomics to identify gene expression patterns operating in Htr3a-GFP+ interneurons during early steps of cortical circuit assembly. We identify three main molecular types of Htr3a-GFP+ interneurons, each displaying distinct developmental dynamics of gene expression. The transcription factor Meis2 is specifically enriched in a type of Htr3a-GFP+ interneurons largely confined to the cortical white matter. These MEIS2-expressing interneurons appear to originate from a restricted region located at the embryonic pallial–subpallial boundary. Overall, this study identifies MEIS2 as a subclass-specific marker for 5-HT3AR-containing interstitial interneurons and demonstrates that the transcriptional and anatomical parcellation of cortical interneurons is developmentally coupled. PMID:28134272

  18. In vivo cell-autonomous transcriptional abnormalities revealed in mice expressing mutant huntingtin in striatal but not cortical neurons.

    PubMed

    Thomas, Elizabeth A; Coppola, Giovanni; Tang, Bin; Kuhn, Alexandre; Kim, SoongHo; Geschwind, Daniel H; Brown, Timothy B; Luthi-Carter, Ruth; Ehrlich, Michelle E

    2011-03-15

    Huntington's disease (HD), caused by a CAG repeat expansion in the huntingtin (HTT) gene, is characterized by abnormal protein aggregates and motor and cognitive dysfunction. Htt protein is ubiquitously expressed, but the striatal medium spiny neuron (MSN) is most susceptible to dysfunction and death. Abnormal gene expression represents a core pathogenic feature of HD, but the relative roles of cell-autonomous and non-cell-autonomous effects on transcription remain unclear. To determine the extent of cell-autonomous dysregulation in the striatum in vivo, we examined genome-wide RNA expression in symptomatic D9-N171-98Q (a.k.a. DE5) transgenic mice in which the forebrain expression of the first 171 amino acids of human Htt with a 98Q repeat expansion is limited to MSNs. Microarray data generated from these mice were compared with those generated on the identical array platform from a pan-neuronal HD mouse model, R6/2, carrying two different CAG repeat lengths, and a relatively high degree of overlap of changes in gene expression was revealed. We further focused on known canonical pathways associated with excitotoxicity, oxidative stress, mitochondrial dysfunction, dopamine signaling and trophic support. While genes related to excitotoxicity, dopamine signaling and trophic support were altered in both DE5 and R6/2 mice, which may be either cell autonomous or non-cell autonomous, genes related to mitochondrial dysfunction, oxidative stress and the peroxisome proliferator-activated receptor are primarily affected in DE5 transgenic mice, indicating cell-autonomous mechanisms. Overall, HD-induced dysregulation of the striatal transcriptome can be largely attributed to intrinsic effects of mutant Htt, in the absence of expression in cortical neurons.

  19. Dynamically Allocated Hub in Task-Evoked Network Predicts the Vulnerable Prefrontal Locus for Contextual Memory Retrieval in Macaques

    PubMed Central

    Osada, Takahiro; Jimura, Koji; Setsuie, Rieko; Miyashita, Yasushi

    2015-01-01

    Neuroimaging and neurophysiology have revealed that multiple areas in the prefrontal cortex (PFC) are activated in a specific memory task, but severity of impairment after PFC lesions is largely different depending on which activated area is damaged. The critical relationship between lesion sites and impairments has not yet been given a clear mechanistic explanation. Although recent works proposed that a whole-brain network contains hubs that play integrative roles in cortical information processing, this framework relying on an anatomy-based structural network cannot account for the vulnerable locus for a specific task, lesioning of which would bring impairment. Here, we hypothesized that (i) activated PFC areas dynamically form an ordered network centered at a task-specific “functional hub” and (ii) the lesion-effective site corresponds to the “functional hub,” but not to a task-invariant “structural hub.” To test these hypotheses, we conducted functional magnetic resonance imaging experiments in macaques performing a temporal contextual memory task. We found that the activated areas formed a hierarchical hub-centric network based on task-evoked directed connectivity, differently from the anatomical network reflecting axonal projection patterns. Using a novel simulated-lesion method based on support vector machine, we estimated severity of impairment after lesioning of each area, which accorded well with a known dissociation in contextual memory impairment in macaques (impairment after lesioning in area 9/46d, but not in area 8Ad). The predicted severity of impairment was proportional to the network “hubness” of the virtually lesioned area in the task-evoked directed connectivity network, rather than in the anatomical network known from tracer studies. Our results suggest that PFC areas dynamically and cooperatively shape a functional hub-centric network to reallocate the lesion-effective site depending on the cognitive processes, apart from

  20. Electrocorticography reveals beta desynchronization in the basal ganglia-cortical loop during rest tremor in Parkinson’s disease

    PubMed Central

    Qasim, Salman E.; de Hemptinne, Coralie; Swann, Nicole C.; Miocinovic, Svjetlana; Ostrem, Jill L.; Starr, Philip A.

    2015-01-01

    The pathophysiology of rest tremor in Parkinson’s disease (PD) is not well understood, and its severity does not correlate with the severity of other cardinal signs of PD. We hypothesized that tremor-related oscillatory activity in the basal-ganglia-thalamocortical loop might serve as a compensatory mechanism for the excessive beta band synchronization associated with the parkinsonian state. We recorded electrocorticography (ECoG) from the sensorimotor cortex and local field potentials (LFP) from the subthalamic nucleus (STN) in patients undergoing lead implantation for deep brain stimulation (DBS). We analyzed differences in measures of network synchronization during epochs of spontaneous rest tremor, versus epochs without rest tremor, occurring in the same subjects. The presence of tremor was associated with reduced beta power in the cortex and STN. Cortico-cortical coherence and phase-amplitude coupling (PAC) decreased during rest tremor, as did basal ganglia-cortical coherence in the same frequency band. Cortical broadband gamma power was not increased by tremor onset, in contrast to the movement-related gamma increase typically observed at the onset of voluntary movement. These findings suggest that the cortical representation of rest tremor is distinct from that of voluntary movement, and support a model in which tremor acts to decrease beta band synchronization within the basal ganglia-cortical loop. PMID:26639855

  1. Electrocorticography reveals beta desynchronization in the basal ganglia-cortical loop during rest tremor in Parkinson's disease.

    PubMed

    Qasim, Salman E; de Hemptinne, Coralie; Swann, Nicole C; Miocinovic, Svjetlana; Ostrem, Jill L; Starr, Philip A

    2016-02-01

    The pathophysiology of rest tremor in Parkinson's disease (PD) is not well understood, and its severity does not correlate with the severity of other cardinal signs of PD. We hypothesized that tremor-related oscillatory activity in the basal-ganglia-thalamocortical loop might serve as a compensatory mechanism for the excessive beta band synchronization associated with the parkinsonian state. We recorded electrocorticography (ECoG) from the sensorimotor cortex and local field potentials (LFP) from the subthalamic nucleus (STN) in patients undergoing lead implantation for deep brain stimulation (DBS). We analyzed differences in measures of network synchronization during epochs of spontaneous rest tremor, versus epochs without rest tremor, occurring in the same subjects. The presence of tremor was associated with reduced beta power in the cortex and STN. Cortico-cortical coherence and phase-amplitude coupling (PAC) decreased during rest tremor, as did basal ganglia-cortical coherence in the same frequency band. Cortical broadband gamma power was not increased by tremor onset, in contrast to the movement-related gamma increase typically observed at the onset of voluntary movement. These findings suggest that the cortical representation of rest tremor is distinct from that of voluntary movement, and support a model in which tremor acts to decrease beta band synchronization within the basal ganglia-cortical loop.

  2. Dissociated multimodal hubs and seizures in temporal lobe epilepsy

    PubMed Central

    Douw, Linda; DeSalvo, Matthew N; Tanaka, Naoaki; Cole, Andrew J; Liu, Hesheng; Reinsberger, Claus; Stufflebeam, Steven M

    2015-01-01

    Objective Brain connectivity at rest is altered in temporal lobe epilepsy (TLE), particularly in “hub” areas such as the posterior default mode network (DMN). Although both functional and anatomical connectivity are disturbed in TLE, the relationships between measures as well as to seizure frequency remain unclear. We aim to clarify these associations using connectivity measures specifically sensitive to hubs. Methods Connectivity between 1000 cortical surface parcels was determined in 49 TLE patients and 23 controls with diffusion and resting-state functional magnetic resonance imaging. Two types of hub connectivity were investigated across multiple brain modules (the DMN, motor system, etcetera): (1) within-module connectivity (a measure of local importance that assesses a parcel's communication level within its own subnetwork) and (2) between-module connectivity (a measure that assesses connections across multiple modules). Results In TLE patients, there was lower overall functional integrity of the DMN as well as an increase in posterior hub connections with other modules. Anatomical between-module connectivity was globally decreased. Higher DMN disintegration (DD) coincided with higher anatomical between-module connectivity, whereas both were associated with increased seizure frequency. DD related to seizure frequency through mediating effects of anatomical connectivity, but seizure frequency also correlated with anatomical connectivity through DD, indicating a complex interaction between multimodal networks and symptoms. Interpretation We provide evidence for dissociated anatomical and functional hub connectivity in TLE. Moreover, shifts in functional hub connections from within to outside the DMN, an overall loss of integrative anatomical communication, and the interaction between the two increase seizure frequency. PMID:25909080

  3. Connectome hubs at resting state in children and adolescents: Reproducibility and psychopathological correlation.

    PubMed

    Sato, João Ricardo; Biazoli, Claudinei Eduardo; Salum, Giovanni Abrahão; Gadelha, Ary; Crossley, Nicolas; Vieira, Gilson; Zugman, André; Picon, Felipe Almeida; Pan, Pedro Mario; Hoexter, Marcelo Queiroz; Anés, Mauricio; Moura, Luciana Monteiro; Del'Aquilla, Marco Antonio Gomes; Junior, Edson Amaro; Mcguire, Philip; Rohde, Luis Augusto; Miguel, Euripedes Constantino; Bressan, Rodrigo Affonseca; Jackowski, Andrea Parolin

    2016-08-01

    Functional brain hubs are key integrative regions in brain networks. Recently, brain hubs identified through resting-state fMRI have emerged as interesting targets to increase understanding of the relationships between large-scale functional networks and psychopathology. However, few studies have directly addressed the replicability and consistency of the hub regions identified and their association with symptoms. Here, we used the eigenvector centrality (EVC) measure obtained from graph analysis of two large, independent population-based samples of children and adolescents (7-15 years old; total N=652; 341 subjects for site 1 and 311 for site 2) to evaluate the replicability of hub identification. Subsequently, we tested the association between replicable hub regions and psychiatric symptoms. We identified a set of hubs consisting of the anterior medial prefrontal cortex and inferior parietal lobule/intraparietal sulcus (IPL/IPS). Moreover, lower EVC values in the right IPS were associated with psychiatric symptoms in both samples. Thus, low centrality of the IPS was a replicable sign of potential vulnerability to mental disorders in children. The identification of critical and replicable hubs in functional cortical networks in children and adolescents can foster understanding of the mechanisms underlying mental disorders.

  4. PolarHub: A Global Hub for Polar Data Discovery

    NASA Astrophysics Data System (ADS)

    Li, W.

    2014-12-01

    This paper reports the outcome of a NSF project in developing a large-scale web crawler PolarHub to discover automatically the distributed polar dataset in the format of OGC web services (OWS) in the cyberspace. PolarHub is a machine robot; its goal is to visit as many webpages as possible to find those containing information about polar OWS, extract this information and store it into the backend data repository. This is a very challenging task given huge data volume of webpages on the Web. Three unique features was introduced in PolarHub to make it distinctive from earlier crawler solutions: (1) a multi-task, multi-user, multi-thread support to the crawling tasks; (2) an extensive use of thread pool and Data Access Object (DAO) design patterns to separate persistent data storage and business logic to achieve high extendibility of the crawler tool; (3) a pattern-matching based customizable crawling algorithm to support discovery of multi-type geospatial web services; and (4) a universal and portable client-server communication mechanism combining a server-push and client pull strategies for enhanced asynchronous processing. A series of experiments were conducted to identify the impact of crawling parameters to the overall system performance. The geographical distribution pattern of all PolarHub identified services is also demonstrated. We expect this work to make a major contribution to the field of geospatial information retrieval and geospatial interoperability, to bridge the gap between data provider and data consumer, and to accelerate polar science by enhancing the accessibility and reusability of adequate polar data.

  5. Optical coherence tomography reveals in vivo cortical structures of adult rats in response to cerebral ischemia injury

    NASA Astrophysics Data System (ADS)

    Ni, Yi-rong; Guo, Zhou-yi; Shu, So-yun; Bao, Xin-min

    2008-12-01

    Optical coherence tomography(OCT) is a high resolution imaging technique which uses light to directly image living tissue. we investigate the potential use of OCT for structural imaging of the ischemia injury mammalian cerebral cortex. And we examine models of middle cerebral artery occlusion (MCAO) in rats in vivo using OCT. In particular, we show that OCT can perform in vivo detection of cortex and differentiate normal and abnormal cortical anatomy. This OCT system in this study provided an axial resolution of 10~15μ m, the transverse resolution of the system is about 25 μm. OCT can provide cross-sectional images of cortical of adult rats in response to cerebral ischemia injury.We conclude that OCT represents an exciting new approach to visualize, in real-time, pathological changes in the cerebral cortex structures and may offer a new tool for Possible neuroscience clinical applications.

  6. Two-photon imaging of cortical surface microvessels reveals a robust redistribution in blood flow after vascular occlusion.

    PubMed

    Schaffer, Chris B; Friedman, Beth; Nishimura, Nozomi; Schroeder, Lee F; Tsai, Philbert S; Ebner, Ford F; Lyden, Patrick D; Kleinfeld, David

    2006-02-01

    A highly interconnected network of arterioles overlies mammalian cortex to route blood to the cortical mantle. Here we test if this angioarchitecture can ensure that the supply of blood is redistributed after vascular occlusion. We use rodent parietal cortex as a model system and image the flow of red blood cells in individual microvessels. Changes in flow are quantified in response to photothrombotic occlusions to individual pial arterioles as well as to physical occlusions of the middle cerebral artery (MCA), the primary source of blood to this network. We observe that perfusion is rapidly reestablished at the first branch downstream from a photothrombotic occlusion through a reversal in flow in one vessel. More distal downstream arterioles also show reversals in flow. Further, occlusion of the MCA leads to reversals in flow through approximately half of the downstream but distant arterioles. Thus the cortical arteriolar network supports collateral flow that may mitigate the effects of vessel obstruction, as may occur secondary to neurovascular pathology.

  7. Gene expression analysis of tuberous sclerosis complex cortical tubers reveals increased expression of adhesion and inflammatory factors

    PubMed Central

    Boer, Karin; Crino, Peter B.; Gorter, Jan A.; Nellist, Mark; Jansen, Floor E.; Spliet, Wim G.M.; van Rijen, Peter C.; Wittink, Floyd R.A.; Breit, Timo M.; Troost, Dirk; Wadman, Wytse J.; Aronica, Eleonora

    2009-01-01

    Cortical tubers in patients with tuberous sclerosis complex are associated with disabling neurological manifestations, including intractable epilepsy. While these malformations are believed to result from the effects of TSC1 or TSC2 gene mutations, the molecular mechanisms leading to tuber formation, as well as the onset of seizures remain largely unknown. We used the Affymetrix Gene Chip platform to provide the first genome wide investigation of gene expression in surgically resected tubers, compared with histological normal perituberal tissue from the same patients or autopsy control tissue. We identified 2501 differentially expressed genes in cortical tubers compared with autopsy controls. Expression of genes associated with cell adhesion e.g., VCAM1, integrins and CD44, or with the inflammatory response, including complement factors, serpinA3, CCL2 and several cytokines, was increased in cortical tubers, whereas genes related to synaptic transmission e.g., the glial glutamate transporter GLT-1, and voltage-gated channel activity, exhibited lower expression. Gene expression in perituberal cortex was distinct from autopsy control cortex suggesting that even in the absence of tissue pathology the transcriptome is altered in TSC. Changes in gene expression yield insights into new candidate genes that may contribute to tuber formation or seizure onset, representing new targets for potential therapeutic development. PMID:19912235

  8. How Big is Too Big for Hubs: Marginal Profitability in Hub-and-Spoke Networks

    NASA Technical Reports Server (NTRS)

    Ross, Leola B.; Schmidt, Stephen J.

    1997-01-01

    Increasing the scale of hub operations at major airports has led to concerns about congestion at excessively large hubs. In this paper, we estimate the marginal cost of adding spokes to an existing hub network. We observe entry/non-entry decisions on potential spokes from existing hubs, and estimate both a variable profit function for providing service in markets using that spoke as well as the fixed costs of providing service to the spoke. We let the fixed costs depend upon the scale of operations at the hub, and find the hub size at which spoke service costs are minimized.

  9. A Unique Four-Hub Protein Cluster Associates to Glioblastoma Progression

    PubMed Central

    Simeone, Pasquale; Trerotola, Marco; Urbanella, Andrea; Lattanzio, Rossano; Ciavardelli, Domenico; Di Giuseppe, Fabrizio; Eleuterio, Enrica; Sulpizio, Marilisa; Eusebi, Vincenzo; Pession, Annalisa; Piantelli, Mauro; Alberti, Saverio

    2014-01-01

    Gliomas are the most frequent brain tumors. Among them, glioblastomas are malignant and largely resistant to available treatments. Histopathology is the gold standard for classification and grading of brain tumors. However, brain tumor heterogeneity is remarkable and histopathology procedures for glioma classification remain unsatisfactory for predicting disease course as well as response to treatment. Proteins that tightly associate with cancer differentiation and progression, can bear important prognostic information. Here, we describe the identification of protein clusters differentially expressed in high-grade versus low-grade gliomas. Tissue samples from 25 high-grade tumors, 10 low-grade tumors and 5 normal brain cortices were analyzed by 2D-PAGE and proteomic profiling by mass spectrometry. This led to identify 48 differentially expressed protein markers between tumors and normal samples. Protein clustering by multivariate analyses (PCA and PLS-DA) provided discrimination between pathological samples to an unprecedented extent, and revealed a unique network of deranged proteins. We discovered a novel glioblastoma control module centered on four major network hubs: Huntingtin, HNF4α, c-Myc and 14-3-3ζ. Immunohistochemistry, western blotting and unbiased proteome-wide meta-analysis revealed altered expression of this glioblastoma control module in human glioma samples as compared with normal controls. Moreover, the four-hub network was found to cross-talk with both p53 and EGFR pathways. In summary, the findings of this study indicate the existence of a unifying signaling module controlling glioblastoma pathogenesis and malignant progression, and suggest novel targets for development of diagnostic and therapeutic procedures. PMID:25050814

  10. Abnormalities in Structural Covariance of Cortical Gyrification in Parkinson's Disease

    PubMed Central

    Xu, Jinping; Zhang, Jiuquan; Zhang, Jinlei; Wang, Yue; Zhang, Yanling; Wang, Jian; Li, Guanglin; Hu, Qingmao; Zhang, Yuanchao

    2017-01-01

    Although abnormal cortical morphology and connectivity between brain regions (structural covariance) have been reported in Parkinson's disease (PD), the topological organizations of large-scale structural brain networks are still poorly understood. In this study, we investigated large-scale structural brain networks in a sample of 37 PD patients and 34 healthy controls (HC) by assessing the structural covariance of cortical gyrification with local gyrification index (lGI). We demonstrated prominent small-world properties of the structural brain networks for both groups. Compared with the HC group, PD patients showed significantly increased integrated characteristic path length and integrated clustering coefficient, as well as decreased integrated global efficiency in structural brain networks. Distinct distributions of hub regions were identified between the two groups, showing more hub regions in the frontal cortex in PD patients. Moreover, the modular analyses revealed significantly decreased integrated regional efficiency in lateral Fronto-Insula-Temporal module, and increased integrated regional efficiency in Parieto-Temporal module in the PD group as compared to the HC group. In summary, our study demonstrated altered topological properties of structural networks at a global, regional and modular level in PD patients. These findings suggests that the structural networks of PD patients have a suboptimal topological organization, resulting in less effective integration of information between brain regions. PMID:28326021

  11. Abnormalities in Structural Covariance of Cortical Gyrification in Parkinson's Disease.

    PubMed

    Xu, Jinping; Zhang, Jiuquan; Zhang, Jinlei; Wang, Yue; Zhang, Yanling; Wang, Jian; Li, Guanglin; Hu, Qingmao; Zhang, Yuanchao

    2017-01-01

    Although abnormal cortical morphology and connectivity between brain regions (structural covariance) have been reported in Parkinson's disease (PD), the topological organizations of large-scale structural brain networks are still poorly understood. In this study, we investigated large-scale structural brain networks in a sample of 37 PD patients and 34 healthy controls (HC) by assessing the structural covariance of cortical gyrification with local gyrification index (lGI). We demonstrated prominent small-world properties of the structural brain networks for both groups. Compared with the HC group, PD patients showed significantly increased integrated characteristic path length and integrated clustering coefficient, as well as decreased integrated global efficiency in structural brain networks. Distinct distributions of hub regions were identified between the two groups, showing more hub regions in the frontal cortex in PD patients. Moreover, the modular analyses revealed significantly decreased integrated regional efficiency in lateral Fronto-Insula-Temporal module, and increased integrated regional efficiency in Parieto-Temporal module in the PD group as compared to the HC group. In summary, our study demonstrated altered topological properties of structural networks at a global, regional and modular level in PD patients. These findings suggests that the structural networks of PD patients have a suboptimal topological organization, resulting in less effective integration of information between brain regions.

  12. Laser speckle contrast imaging reveals large-scale synchronization of cortical autoregulation dynamics influenced by nitric oxide.

    PubMed

    Mitrou, Nicholas; Scully, Christopher G; Braam, Branko; Chon, Ki H; Cupples, William A

    2015-04-01

    Synchronization of tubuloglomerular feedback (TGF) dynamics in nephrons that share a cortical radial artery is well known. It is less clear whether synchronization extends beyond a single cortical radial artery or whether it extends to the myogenic response (MR). We used LSCI to examine cortical perfusion dynamics in isoflurane-anesthetized, male Long-Evans rats. Inhibition of nitric oxide synthases by N(ω)-nitro-l-arginine methyl ester (l-NAME) was used to alter perfusion dynamics. Phase coherence (PC) was determined between all possible pixel pairs in either the MR or TGF band (0.09-0.3 and 0.015-0.06 Hz, respectively). The field of view (≈4 × 5 mm) was segmented into synchronized clusters based on mutual PC. During the control period, the field of view was often contained within one cluster for both MR and TGF. PC was moderate for TGF and modest for MR, although significant in both. In both MR and TGF, PC exhibited little spatial variation. After l-NAME, the number of clusters increased in both MR and TGF. MR clusters became more strongly synchronized while TGF clusters showed small highly coupled, high-PC regions that were coupled with low PC to the remainder of the cluster. Graph theory analysis probed modularity of synchronization. It confirmed weak synchronization of MR during control that probably was not physiologically relevant. It confirmed extensive and long-distance synchronization of TGF during control and showed increased modularity, albeit with larger modules seen in MR than in TGF after l-NAME. The results show widespread synchronization of MR and TGF that is differentially affected by nitric oxide. Copyright © 2015 the American Physiological Society.

  13. Revealing unobserved factors underlying cortical activity with a rectified latent variable model applied to neural population recordings.

    PubMed

    Whiteway, Matthew R; Butts, Daniel A

    2017-03-01

    The activity of sensory cortical neurons is not only driven by external stimuli but also shaped by other sources of input to the cortex. Unlike external stimuli, these other sources of input are challenging to experimentally control, or even observe, and as a result contribute to variability of neural responses to sensory stimuli. However, such sources of input are likely not "noise" and may play an integral role in sensory cortex function. Here we introduce the rectified latent variable model (RLVM) in order to identify these sources of input using simultaneously recorded cortical neuron populations. The RLVM is novel in that it employs nonnegative (rectified) latent variables and is much less restrictive in the mathematical constraints on solutions because of the use of an autoencoder neural network to initialize model parameters. We show that the RLVM outperforms principal component analysis, factor analysis, and independent component analysis, using simulated data across a range of conditions. We then apply this model to two-photon imaging of hundreds of simultaneously recorded neurons in mouse primary somatosensory cortex during a tactile discrimination task. Across many experiments, the RLVM identifies latent variables related to both the tactile stimulation as well as nonstimulus aspects of the behavioral task, with a majority of activity explained by the latter. These results suggest that properly identifying such latent variables is necessary for a full understanding of sensory cortical function and demonstrate novel methods for leveraging large population recordings to this end.NEW & NOTEWORTHY The rapid development of neural recording technologies presents new opportunities for understanding patterns of activity across neural populations. Here we show how a latent variable model with appropriate nonlinear form can be used to identify sources of input to a neural population and infer their time courses. Furthermore, we demonstrate how these sources are

  14. Local domains of motor cortical activity revealed by fiber-optic calcium recordings in behaving nonhuman primates

    PubMed Central

    Adelsberger, Helmuth; Zainos, Antonio; Alvarez, Manuel; Romo, Ranulfo; Konnerth, Arthur

    2014-01-01

    Brain mapping experiments involving electrical microstimulation indicate that the primary motor cortex (M1) directly regulates muscle contraction and thereby controls specific movements. Possibly, M1 contains a small circuit “map” of the body that is formed by discrete local networks that code for specific movements. Alternatively, movements may be controlled by distributed, larger-scale overlapping circuits. Because of technical limitations, it remained unclear how movement-determining circuits are organized in M1. Here we introduce a method that allows the functional mapping of small local neuronal circuits in awake behaving nonhuman primates. For this purpose, we combined optic-fiber–based calcium recordings of neuronal activity and cortical microstimulation. The method requires targeted bulk loading of synthetic calcium indicators (e.g., OGB-1 AM) for the staining of neuronal microdomains. The tip of a thin (200 µm) optical fiber can detect the coherent activity of a small cluster of neurons, but is insensitive to the asynchronous activity of individual cells. By combining such optical recordings with microstimulation at two well-separated sites of M1, we demonstrate that local cortical activity was tightly associated with distinct and stereotypical simple movements. Increasing stimulation intensity increased both the amplitude of the movements and the level of neuronal activity. Importantly, the activity remained local, without invading the recording domain of the second optical fiber. Furthermore, there was clear response specificity at the two recording sites in a trained behavioral task. Thus, the results provide support for movement control in M1 by local neuronal clusters that are organized in discrete cortical domains. PMID:24344287

  15. Local domains of motor cortical activity revealed by fiber-optic calcium recordings in behaving nonhuman primates.

    PubMed

    Adelsberger, Helmuth; Zainos, Antonio; Alvarez, Manuel; Romo, Ranulfo; Konnerth, Arthur

    2014-01-07

    Brain mapping experiments involving electrical microstimulation indicate that the primary motor cortex (M1) directly regulates muscle contraction and thereby controls specific movements. Possibly, M1 contains a small circuit "map" of the body that is formed by discrete local networks that code for specific movements. Alternatively, movements may be controlled by distributed, larger-scale overlapping circuits. Because of technical limitations, it remained unclear how movement-determining circuits are organized in M1. Here we introduce a method that allows the functional mapping of small local neuronal circuits in awake behaving nonhuman primates. For this purpose, we combined optic-fiber-based calcium recordings of neuronal activity and cortical microstimulation. The method requires targeted bulk loading of synthetic calcium indicators (e.g., OGB-1 AM) for the staining of neuronal microdomains. The tip of a thin (200 µm) optical fiber can detect the coherent activity of a small cluster of neurons, but is insensitive to the asynchronous activity of individual cells. By combining such optical recordings with microstimulation at two well-separated sites of M1, we demonstrate that local cortical activity was tightly associated with distinct and stereotypical simple movements. Increasing stimulation intensity increased both the amplitude of the movements and the level of neuronal activity. Importantly, the activity remained local, without invading the recording domain of the second optical fiber. Furthermore, there was clear response specificity at the two recording sites in a trained behavioral task. Thus, the results provide support for movement control in M1 by local neuronal clusters that are organized in discrete cortical domains.

  16. Differential sensitivity of brainstem versus cortical astrocytes to changes in pH reveals functional regional specialization of astroglia.

    PubMed

    Kasymov, Vitaliy; Larina, Olga; Castaldo, Cinzia; Marina, Nephtali; Patrushev, Maxim; Kasparov, Sergey; Gourine, Alexander V

    2013-01-09

    Astrocytes might function as brain interoceptors capable of detecting different (chemo)sensory modalities and transmitting sensory information to the relevant neural networks controlling vital functions. For example, astrocytes that reside near the ventral surface of the brainstem (central respiratory chemosensitive area) respond to physiological decreases in pH with vigorous elevations in intracellular Ca(2+) and release of ATP. ATP transmits astroglial excitation to the brainstem respiratory network and contributes to adaptive changes in lung ventilation. Here we show that in terms of pH-sensitivity, ventral brainstem astrocytes are clearly distinct from astrocytes residing in the cerebral cortex. We monitored vesicular fusion in cultured rat brainstem astrocytes using total internal reflection fluorescence microscopy and found that ∼35% of them respond to acidification with an increased rate of exocytosis of ATP-containing vesicular compartments. These fusion events require intracellular Ca(2+) signaling and are independent of autocrine ATP actions. In contrast, the rate of vesicular fusion in cultured cortical astrocytes is not affected by changes in pH. Compared to cortical astrocytes, ventral brainstem astrocytes display higher levels of expression of genes encoding proteins associated with ATP vesicular transport and fusion, including vesicle-associated membrane protein-3 and vesicular nucleotide transporter. These results suggest that astrocytes residing in different parts of the rat brain are functionally specialized. In contrast to cortical astrocytes, astrocytes of the brainstem chemosensitive area(s) possess signaling properties that are functionally relevant-they are able to sense changes in pH and respond to acidification with enhanced vesicular release of ATP.

  17. Divergent Expression Patterns in Two Vernicia Species Revealed the Potential Role of the Hub Gene VmAP2/ERF036 in Resistance to Fusarium oxysporum in Vernicia montana

    PubMed Central

    Zhang, Qiyan; Gao, Ming; Wu, Liwen; Wang, Yangdong; Chen, Yicun

    2016-01-01

    Tung oil tree (Vernicia fordii) is a promising industrial oil crop; however, this tree is highly susceptible to Fusarium wilt disease. Conversely, Vernicia montana is resistant to the pathogen. The APETALA2/ethylene-responsive element binding factor (AP2/ERF) transcription factor superfamily has been reported to play a significant role in resistance to Fusarium oxysporum. In this study, comprehensive analysis identified 75 and 81 putative Vf/VmAP2/ERF transcription factor-encoding genes in V. fordii and V. montana, respectively, which were divided into AP2, ERF, related to ABI3 and VP1 (RAV) and Soloist families. After F. oxysporum infection, a majority of AP2/ERF superfamily genes showed strong patterns of repression in both V. fordii and V. montana. We then identified 53 pairs of one-to-one orthologs in V. fordii and V. montana, with most pairs of orthologous genes exhibiting similar expression in response to the pathogen. Further investigation of Vf/VmAP2/ERF gene expression in plant tissues indicated that the pairs of genes with different expression patterns in response to F. oxysporum tended to exhibit different tissue profiles in the two species. In addition, VmAP2/ERF036, showing the strongest interactions with 666 genes, was identified as a core hub gene mediating resistance. Moreover, qRT-PCR results indicated VmAP2/ERF036 showed repressed expression while its orthologous gene VfAP2/ERF036 had the opposite expression pattern during pathogen infection. Overall, comparative analysis of the Vf/VmAP2/ERF superfamily and indication of a potential hub resistance gene in resistant and susceptible Vernicia species provides valuable information for understanding the molecular basis and selection of essential functional genes for V. fordii genetic engineering to control Fusarium wilt disease. PMID:27916924

  18. Hub Effects in Propeller Design and Analysis

    DTIC Science & Technology

    1985-07-01

    x^ is a cubic function which is best fit with real hub fairing. The interval between x = x and x = x is 12 an artificial forebody to make this...Geometry and Hub Modeling Real hub geometry, as well as a best fit hub geometry with r„ = 0.3, X = 0.012, and x = 0.761, and the equation (3.3) are...Six Blades," David Tayor Model Basin Report 1141, June 1957. Thorsen, T.L., "Approximate Theory for the Optimum Circulation Distribution for

  19. Auditory Selective Attention Reveals Preparatory Activity in Different Cortical Regions for Selection Based on Source Location and Source Pitch

    PubMed Central

    Lee, Adrian K. C.; Rajaram, Siddharth; Xia, Jing; Bharadwaj, Hari; Larson, Eric; Hämäläinen, Matti S.; Shinn-Cunningham, Barbara G.

    2012-01-01

    In order to extract information in a rich environment, we focus on different features that allow us to direct attention to whatever source is of interest. The cortical network deployed during spatial attention, especially in vision, is well characterized. For example, visuospatial attention engages a frontoparietal network including the frontal eye fields (FEFs), which modulate activity in visual sensory areas to enhance the representation of an attended visual object. However, relatively little is known about the neural circuitry controlling attention directed to non-spatial features, or to auditory objects or features (either spatial or non-spatial). Here, using combined magnetoencephalography (MEG) and anatomical information obtained from MRI, we contrasted cortical activity when observers attended to different auditory features given the same acoustic mixture of two simultaneous spoken digits. Leveraging the fine temporal resolution of MEG, we establish that activity in left FEF is enhanced both prior to and throughout the auditory stimulus when listeners direct auditory attention to target location compared to when they focus on target pitch. In contrast, activity in the left posterior superior temporal sulcus (STS), a region previously associated with auditory pitch categorization, is greater when listeners direct attention to target pitch rather than target location. This differential enhancement is only significant after observers are instructed which cue to attend, but before the acoustic stimuli begin. We therefore argue that left FEF participates more strongly in directing auditory spatial attention, while the left STS aids auditory object selection based on the non-spatial acoustic feature of pitch. PMID:23335874

  20. Delineating function and connectivity of optokinetic hubs in the cerebellum and the brainstem.

    PubMed

    Ruehl, Ria Maxine; Hinkel, Carolin; Bauermann, Thomas; Eulenburg, Peter Zu

    2017-06-23

    Optokinetic eye movements are crucial for keeping a stable image on the retina during movements of the head. These eye movements can be differentiated into a cortically generated response (optokinetic look nystagmus) and the highly reflexive optokinetic stare nystagmus, which is controlled by circuits in the brainstem and cerebellum. The contributions of these infratentorial networks and their functional connectivity with the cortical eye fields are still poorly understood in humans. To map ocular motor centres in the cerebellum and brainstem, we studied stare nystagmus using small-field optokinetic stimuli in the horizontal and vertical directions in 22 healthy subjects. We were able to differentiate ocular motor areas of the pontine brainstem and midbrain in vivo for the first time. Direction and velocity-dependent activations were found in the pontine brainstem (nucleus reticularis, tegmenti pontis, and paramedian pontine reticular formation), the uvula, flocculus, and cerebellar tonsils. The ocular motor vermis, on the other hand, responded to constant and accelerating velocity stimulation. Moreover, deactivation patterns depict a governing role for the cerebellar tonsils in ocular motor control. Functional connectivity results of these hubs reveal the close integration of cortico-cerebellar ocular motor and vestibular networks in humans. Adding to the cortical concept of a right-hemispheric predominance for visual-spatial processing, we found a complementary left-sided cerebellar dominance for our ocular motor task. A deeper understanding of the role of the cerebellum and especially the cerebellar tonsils for eye movement control in a clinical context seems vitally important and is now feasible with functional neuroimaging.

  1. Trade-off between Multiple Constraints Enables Simultaneous Formation of Modules and Hubs in Neural Systems

    PubMed Central

    Chen, Yuhan; Wang, Shengjun; Hilgetag, Claus C.; Zhou, Changsong

    2013-01-01

    The formation of the complex network architecture of neural systems is subject to multiple structural and functional constraints. Two obvious but apparently contradictory constraints are low wiring cost and high processing efficiency, characterized by short overall wiring length and a small average number of processing steps, respectively. Growing evidence shows that neural networks are results from a trade-off between physical cost and functional value of the topology. However, the relationship between these competing constraints and complex topology is not well understood quantitatively. We explored this relationship systematically by reconstructing two known neural networks, Macaque cortical connectivity and C. elegans neuronal connections, from combinatory optimization of wiring cost and processing efficiency constraints, using a control parameter , and comparing the reconstructed networks to the real networks. We found that in both neural systems, the reconstructed networks derived from the two constraints can reveal some important relations between the spatial layout of nodes and the topological connectivity, and match several properties of the real networks. The reconstructed and real networks had a similar modular organization in a broad range of , resulting from spatial clustering of network nodes. Hubs emerged due to the competition of the two constraints, and their positions were close to, and partly coincided, with the real hubs in a range of values. The degree of nodes was correlated with the density of nodes in their spatial neighborhood in both reconstructed and real networks. Generally, the rebuilt network matched a significant portion of real links, especially short-distant ones. These findings provide clear evidence to support the hypothesis of trade-off between multiple constraints on brain networks. The two constraints of wiring cost and processing efficiency, however, cannot explain all salient features in the real networks. The discrepancy

  2. Trade-off between multiple constraints enables simultaneous formation of modules and hubs in neural systems.

    PubMed

    Chen, Yuhan; Wang, Shengjun; Hilgetag, Claus C; Zhou, Changsong

    2013-01-01

    The formation of the complex network architecture of neural systems is subject to multiple structural and functional constraints. Two obvious but apparently contradictory constraints are low wiring cost and high processing efficiency, characterized by short overall wiring length and a small average number of processing steps, respectively. Growing evidence shows that neural networks are results from a trade-off between physical cost and functional value of the topology. However, the relationship between these competing constraints and complex topology is not well understood quantitatively. We explored this relationship systematically by reconstructing two known neural networks, Macaque cortical connectivity and C. elegans neuronal connections, from combinatory optimization of wiring cost and processing efficiency constraints, using a control parameter α, and comparing the reconstructed networks to the real networks. We found that in both neural systems, the reconstructed networks derived from the two constraints can reveal some important relations between the spatial layout of nodes and the topological connectivity, and match several properties of the real networks. The reconstructed and real networks had a similar modular organization in a broad range of α, resulting from spatial clustering of network nodes. Hubs emerged due to the competition of the two constraints, and their positions were close to, and partly coincided, with the real hubs in a range of α values. The degree of nodes was correlated with the density of nodes in their spatial neighborhood in both reconstructed and real networks. Generally, the rebuilt network matched a significant portion of real links, especially short-distant ones. These findings provide clear evidence to support the hypothesis of trade-off between multiple constraints on brain networks. The two constraints of wiring cost and processing efficiency, however, cannot explain all salient features in the real networks. The

  3. Helicopter hub fairing and pylon interference drag

    NASA Technical Reports Server (NTRS)

    Graham, D. R.; Sung, D. Y.; Young, L. A.; Louie, A. W.; Stroub, R. H.

    1989-01-01

    A wind tunnel test was conducted to study the aerodynamics of helicopter hub and pylon fairings. The test was conducted in the 7-by 10 Foot Subsonic Wind Tunnel (Number 2) at Ames Research Center using a 1/5-scale XH-59A fuselage model. The primary focus of the test was on the rotor hub fairing and pylon mutual interference drag. Parametric studies of pylon and hub fairing geometry were also conducted. This report presents the major findings of the test as well as tabulated force and moment data, flow visualization photographs, and graphical presentations of the drag data. The test results indicate that substantial drag reduction can be attained through the use of a cambered hub fairing with circular arc upper surface and flat lower surface. Furthermore, a considerable portion of the overall drag reduction is attributed to the reduction in the hub-on-pylon interference drag. It is also observed that the lower surface curvature of the fairing has a strong influence on the hub fairing and on pylon interference drag. However, the drag reduction benefit that was obtained by using the cambered hub fairing with a flat lower surface was adversely affected by the clearance between the hub fairing and the pylon.

  4. Fixation based event-related fmri analysis: using eye fixations as events in functional magnetic resonance imaging to reveal cortical processing during the free exploration of visual images.

    PubMed

    Marsman, Jan Bernard C; Renken, Remco; Velichkovsky, Boris M; Hooymans, Johanna M M; Cornelissen, Frans W

    2012-02-01

    Eye movements, comprising predominantly fixations and saccades, are known to reveal information about perception and cognition, and they provide an explicit measure of attention. Nevertheless, fixations have not been considered as events in the analyses of data obtained during functional magnetic resonance imaging (fMRI) experiments. Most likely, this is due to their brevity and statistical properties. Despite these limitations, we used fixations as events to model brain activation in a free viewing experiment with standard fMRI scanning parameters. First, we found that fixations on different objects in different task contexts resulted in distinct cortical patterns of activation. Second, using multivariate pattern analysis, we showed that the BOLD signal revealed meaningful information about the task context of individual fixations and about the object being inspected during these fixations. We conclude that fixation-based event-related (FIBER) fMRI analysis creates new pathways for studying human brain function by enabling researchers to explore natural viewing behavior.

  5. Adolescence is associated with genomically patterned consolidation of the hubs of the human brain connectome

    PubMed Central

    Romero-Garcia, Rafael; Váša, František; Moutoussis, Michael; Prabhu, Gita; Weiskopf, Nikolaus; Callaghan, Martina F.; Wagstyl, Konrad; Rittman, Timothy; Tait, Roger; Ooi, Cinly; Suckling, John; Inkster, Becky; Fonagy, Peter; Dolan, Raymond J.; Jones, Peter B.; Goodyer, Ian M.

    2016-01-01

    How does human brain structure mature during adolescence? We used MRI to measure cortical thickness and intracortical myelination in 297 population volunteers aged 14–24 y old. We found and replicated that association cortical areas were thicker and less myelinated than primary cortical areas at 14 y. However, association cortex had faster rates of shrinkage and myelination over the course of adolescence. Age-related increases in cortical myelination were maximized approximately at the internal layer of projection neurons. Adolescent cortical myelination and shrinkage were coupled and specifically associated with a dorsoventrally patterned gene expression profile enriched for synaptic, oligodendroglial- and schizophrenia-related genes. Topologically efficient and biologically expensive hubs of the brain anatomical network had greater rates of shrinkage/myelination and were associated with overexpression of the same transcriptional profile as cortical consolidation. We conclude that normative human brain maturation involves a genetically patterned process of consolidating anatomical network hubs. We argue that developmental variation of this consolidation process may be relevant both to normal cognitive and behavioral changes and the high incidence of schizophrenia during human brain adolescence. PMID:27457931

  6. Adolescence is associated with genomically patterned consolidation of the hubs of the human brain connectome.

    PubMed

    Whitaker, Kirstie J; Vértes, Petra E; Romero-Garcia, Rafael; Váša, František; Moutoussis, Michael; Prabhu, Gita; Weiskopf, Nikolaus; Callaghan, Martina F; Wagstyl, Konrad; Rittman, Timothy; Tait, Roger; Ooi, Cinly; Suckling, John; Inkster, Becky; Fonagy, Peter; Dolan, Raymond J; Jones, Peter B; Goodyer, Ian M; Bullmore, Edward T

    2016-08-09

    How does human brain structure mature during adolescence? We used MRI to measure cortical thickness and intracortical myelination in 297 population volunteers aged 14-24 y old. We found and replicated that association cortical areas were thicker and less myelinated than primary cortical areas at 14 y. However, association cortex had faster rates of shrinkage and myelination over the course of adolescence. Age-related increases in cortical myelination were maximized approximately at the internal layer of projection neurons. Adolescent cortical myelination and shrinkage were coupled and specifically associated with a dorsoventrally patterned gene expression profile enriched for synaptic, oligodendroglial- and schizophrenia-related genes. Topologically efficient and biologically expensive hubs of the brain anatomical network had greater rates of shrinkage/myelination and were associated with overexpression of the same transcriptional profile as cortical consolidation. We conclude that normative human brain maturation involves a genetically patterned process of consolidating anatomical network hubs. We argue that developmental variation of this consolidation process may be relevant both to normal cognitive and behavioral changes and the high incidence of schizophrenia during human brain adolescence.

  7. Schizophrenia and abnormal brain network hubs.

    PubMed

    Rubinov, Mikail; Bullmore, Ed

    2013-09-01

    Schizophrenia is a heterogeneous psychiatric disorder of unknown cause or characteristic pathology. Clinical neuroscientists increasingly postulate that schizophrenia is a disorder of brain network organization. In this article we discuss the conceptual framework of this dysconnection hypothesis, describe the predominant methodological paradigm for testing this hypothesis, and review recent evidence for disruption of central/hub brain regions, as a promising example of this hypothesis. We summarize studies of brain hubs in large-scale structural and functional brain networks and find strong evidence for network abnormalities of prefrontal hubs, and moderate evidence for network abnormalities of limbic, temporal, and parietal hubs. Future studies are needed to differentiate network dysfunction from previously observed gray- and white-matter abnormalities of these hubs, and to link endogenous network dysfunction phenotypes with perceptual, behavioral, and cognitive clinical phenotypes of schizophrenia.

  8. 75 FR 10230 - Mississippi Hub, LLC; Notice of Amendment Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-05

    ...] Mississippi Hub, LLC; Notice of Amendment Application February 25, 2010. On February 8, 2010, Mississippi Hub... be directed to William Rapp, Mississippi Hub, LLC, 101 Ash Street, San Diego, CA 92101, (619)...

  9. Genomic and immunohistochemical analysis in human adrenal cortical neoplasia reveal beta-catenin mutations as potential prognostic biomarker.

    PubMed

    Kovach, Alexandra E; Nucera, Carmelo; Lam, Quynh T; Nguyen, Ahnthu; Dias-Santagata, Dora; Sadow, Peter M

    2015-01-01

    Evaluation for malignancy of the adrenal cortex, adrenal cortical carcinoma (ACC), is a challenge in surgical pathology due to its relative rarity and histologic overlap with its benign counterpart, adrenocortical adenoma (ACA). We characterized a cohort of human ACC and ACA, including a molecular screen, with a goal of identifying potential diagnostic adjuncts. Thirty-six cases of ACC underwent histologic and clinical review. In the 31 ACC cases with available material and a cohort of 10 ACA cases, a multiplex nucleotide amplification molecular screen from formalin-fixed, paraffin-embedded tissue was peformed. ACCs demonstrated a wide variety of clinical and histologic characteristics with overall poor but unpredictable survival for subjects with ACC. By mutational screen, 12/31 (38.7%) carcinomas harbored CTNNB1 mutations, 1 with an additional TP53 mutation; 1 case each had isolated APC and TP53 mutations; 16 were wild-type for all tested loci; and 1 case demonstrated repeated assay failures. Two of the 10 ACA (20%) demonstrated CTNNB1 mutations by mutational screen, with no additional mutations. Immunohistochemistry for beta-catenin was performed and compared with the results of the molecular screen. Strong nuclear beta-catenin immunopositivity corresponded to the presence of CTNNB1 mutation by genotyping in 10 of 12 cases (83% sensitivity); the mismatched case(s) demonstrated strong membranous staining by immunohistochemistry. Seventeen of the 18 cases without CTNNB1 mutation showed membranous staining or did not stain (94% specificity); the mismatched case demonstrated scattered (<10%) positive nuclei. Both mutations in ACA were corroborated with immunohistochemistry for beta-catenin. No histomorphologic parameter appeared dominant in lesions with a particular mutational status. Based on these results, mutational status of CTNNB1 in adrenal cortical neoplasms can be predicted with reasonable accuracy by immunohistochemical cellular localization. Nuclear

  10. Cortical Auditory Evoked Potentials Reveal Changes in Audibility with Nonlinear Frequency Compression in Hearing Aids for Children: Clinical Implications.

    PubMed

    Ching, Teresa Y C; Zhang, Vicky W; Hou, Sanna; Van Buynder, Patricia

    2016-02-01

    Hearing loss in children is detected soon after birth via newborn hearing screening. Procedures for early hearing assessment and hearing aid fitting are well established, but methods for evaluating the effectiveness of amplification for young children are limited. One promising approach to validating hearing aid fittings is to measure cortical auditory evoked potentials (CAEPs). This article provides first a brief overview of reports on the use of CAEPs for evaluation of hearing aids. Second, a study that measured CAEPs to evaluate nonlinear frequency compression (NLFC) in hearing aids for 27 children (between 6.1 and 16.8 years old) who have mild to severe hearing loss is reported. There was no significant difference in aided sensation level or the detection of CAEPs for /g/ between NLFC on and off conditions. The activation of NLFC was associated with a significant increase in aided sensation levels for /t/ and /s/. It also was associated with an increase in detection of CAEPs for /t/ and /s/. The findings support the use of CAEPs for checking audibility provided by hearing aids. Based on the current data, a clinical protocol for using CAEPs to validate audibility with amplification is presented.

  11. Cortical Auditory Evoked Potentials Reveal Changes in Audibility with Nonlinear Frequency Compression in Hearing Aids for Children: Clinical Implications

    PubMed Central

    Ching, Teresa Y. C.; Zhang, Vicky W.; Hou, Sanna; Van Buynder, Patricia

    2016-01-01

    Hearing loss in children is detected soon after birth via newborn hearing screening. Procedures for early hearing assessment and hearing aid fitting are well established, but methods for evaluating the effectiveness of amplification for young children are limited. One promising approach to validating hearing aid fittings is to measure cortical auditory evoked potentials (CAEPs). This article provides first a brief overview of reports on the use of CAEPs for evaluation of hearing aids. Second, a study that measured CAEPs to evaluate nonlinear frequency compression (NLFC) in hearing aids for 27 children (between 6.1 and 16.8 years old) who have mild to severe hearing loss is reported. There was no significant difference in aided sensation level or the detection of CAEPs for /g/ between NLFC on and off conditions. The activation of NLFC was associated with a significant increase in aided sensation levels for /t/ and /s/. It also was associated with an increase in detection of CAEPs for /t/ and /s/. The findings support the use of CAEPs for checking audibility provided by hearing aids. Based on the current data, a clinical protocol for using CAEPs to validate audibility with amplification is presented. PMID:27587920

  12. Quantitative Live Imaging of Human Embryonic Stem Cell Derived Neural Rosettes Reveals Structure-Function Dynamics Coupled to Cortical Development.

    PubMed

    Ziv, Omer; Zaritsky, Assaf; Yaffe, Yakey; Mutukula, Naresh; Edri, Reuven; Elkabetz, Yechiel

    2015-10-01

    Neural stem cells (NSCs) are progenitor cells for brain development, where cellular spatial composition (cytoarchitecture) and dynamics are hypothesized to be linked to critical NSC capabilities. However, understanding cytoarchitectural dynamics of this process has been limited by the difficulty to quantitatively image brain development in vivo. Here, we study NSC dynamics within Neural Rosettes--highly organized multicellular structures derived from human pluripotent stem cells. Neural rosettes contain NSCs with strong epithelial polarity and are expected to perform apical-basal interkinetic nuclear migration (INM)--a hallmark of cortical radial glial cell development. We developed a quantitative live imaging framework to characterize INM dynamics within rosettes. We first show that the tendency of cells to follow the INM orientation--a phenomenon we referred to as radial organization, is associated with rosette size, presumably via mechanical constraints of the confining structure. Second, early forming rosettes, which are abundant with founder NSCs and correspond to the early proliferative developing cortex, show fast motions and enhanced radial organization. In contrast, later derived rosettes, which are characterized by reduced NSC capacity and elevated numbers of differentiated neurons, and thus correspond to neurogenesis mode in the developing cortex, exhibit slower motions and decreased radial organization. Third, later derived rosettes are characterized by temporal instability in INM measures, in agreement with progressive loss in rosette integrity at later developmental stages. Finally, molecular perturbations of INM by inhibition of actin or non-muscle myosin-II (NMII) reduced INM measures. Our framework enables quantification of cytoarchitecture NSC dynamics and may have implications in functional molecular studies, drug screening, and iPS cell-based platforms for disease modeling.

  13. White matter abnormalities in patients with focal cortical dysplasia revealed by diffusion tensor imaging analysis in a voxelwise approach.

    PubMed

    Fonseca, Viviane de Carvalho; Yasuda, Clarissa Lin; Tedeschi, Guilherme Garlipp; Betting, Luiz Eduardo; Cendes, Fernando

    2012-01-01

    Diffusion tensor imaging (DTI) allows the analysis of changes in microstructure, through the quantification of the spread and direction of water molecules in tissues. We used fractional anisotropy (FA) maps to compare the integrity of WM between patients and controls. The objective of the present study was to investigate WM abnormalities in patients with frontal lobe epilepsy secondary to focal cortical dysplasia (FCD). We included 31 controls (12 women, 33.1 ± 9.6 years, mean ± SD) and 22 patients (11 women, 30.4 ± 10.0 years), recruited from our outpatient clinic. They had clinical and EEG diagnosis of frontal lobe epilepsy, secondary to FCD detected on MRI. Patients and controls underwent 3T MRI, including the DTI sequence, obtained in 32 directions and b value of 1000 s/mm(2). To process the DTI we used the following softwares: MRIcroN and FSL/TBSS (tract-based spatial statistics). We used a threshold-free cluster enhancement with significance at p < 0.05, fully corrected for multiple comparisons across space. Areas with FA reduction in patients were identified in both hemispheres, mainly in the frontal lobes, cingulum, and forceps minor (p = 0.014), caudate e anterior thalamic radiation (p = 0.034), superior longitudinal fasciculus (p = 0.044), uncinate fasciculus, and inferior fronto-occipital fasciculus (p = 0.042). Our results showed a widespread pattern of WM microstructural abnormalities extending beyond the main lesion seen on MRI (frontal lobe), which may be related to frequent seizures or to the extent of MRI-invisible portion of FCD.

  14. Hubs to spread technology and save lives.

    PubMed

    Humphreys, Gary

    2015-05-01

    The patent on an expensive preventive treatment for respiratory syncytial virus infections expires this year. A WHO technology transfer hub in the Netherlands aims to help developing countries make the drug themselves. Gary Humphreys reports.

  15. Hub flexibility effects on propfan vibration

    NASA Technical Reports Server (NTRS)

    Ernst, Michael A.; Lawrence, Charles

    1987-01-01

    The significance of hub flexibility in the nonlinear static and dynamic analyses of advanced turboprop blades is assessed. The chosen blade is the 0.175 scale model of the GE-A7-B4 unducted fan blade. A procedure for coupling the effective hub stiffness matrix to an MSC/NASTRAN finite element model is defined and verified. A series of nonlinear static and dynamic analyses are conducted on the blade for both rigid and flexible hug configurations. Results indicate that hub flexibility is significant in the nonlinear static and dynamic analyses of the GE-A7-B4. In order to insure accuracy in analyses of other blades, hub flexibility should always be considered.

  16. Emerging hubs in phantom perception connectomics

    PubMed Central

    Mohan, Anusha; De Ridder, Dirk; Vanneste, Sven

    2016-01-01

    Brain networks are small-world networks typically characterized by the presence of hubs, i.e. nodes that have significantly greater number of links in comparison to other nodes in the network. These hubs act as short cuts in the network and promote long-distance connectivity. Long-distance connections increase the efficiency of information transfer but also increase the cost of the network. Brain disorders are associated with an altered brain connectome which reflects either as a complete change in the network topology, as in, the replacement of hubs or as an alteration in the connectivity between the hubs while retaining network structure. The current study compares the network topology of binary and weighted networks in tinnitus patients and healthy controls by studying the hubs of the two networks in different oscillatory bands. The EEG of 311 tinnitus patients and 256 control subjects are recorded, pre-processed and source-localized using sLORETA. The hubs of the different binary and weighted networks are identified using different measures of network centrality. The results suggest that the tinnitus and control networks are distinct in all the frequency bands but substantially overlap in the gamma frequency band. The differences in network topology in the tinnitus and control groups in the delta, theta and the higher beta bands are driven by a change in hubs as well as network connectivity; in the alpha band by changes in hubs alone and in the gamma band by changes in network connectivity. Thus the brain seems to employ different frequency band-dependent adaptive mechanisms trying to compensate for auditory deafferentation. PMID:26955514

  17. 78 FR 38704 - Mississippi Hub, LLC; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-27

    ... Energy Regulatory Commission Mississippi Hub, LLC; Notice of Application Take notice that on June 10, 2013, Mississippi Hub, LLC (MS Hub) filed an application pursuant to Section 7 of the Natural Gas Act... capacity of Cavern 3 located at MS Hub Storage Terminal in Simpson County, Mississippi. This filing...

  18. Parasite-Drag Measurements of Five Helicopter Rotor Hubs

    NASA Technical Reports Server (NTRS)

    Churchill, Gary B.; Harrington, Robert D.

    1959-01-01

    An investigation has been conducted in the Langley full-scale tunnel to determine the parasite drag of five production-type helicopter rotor hubs. Some simple fairing arrangements were attempted in an effort to reduce the hub drag. The results indicate that, within the range of the tests, changes in angle of attack, hub rotational speed, and forward speed generally had only a small effect on the equivalent flat-plate area representing parasite drag. The drag coefficients of the basic hubs, based on projected hub frontal area, increased with hub area and varied from 0.5 to 0.76 for the hubs tested.

  19. An Experimental Investigation of Helicopter Rotor Hub Fairing Drag Characteristics

    NASA Technical Reports Server (NTRS)

    Sung, D. Y.; Lance, M. B.; Young, L. A.; Stroub, R. H.

    1989-01-01

    A study was done in the NASA 14- by 22-Foot Wind Tunnel at Langley Research Center on the parasite drag of different helicopter rotor hub fairings and pylons. Parametric studies of hub-fairing camber and diameter were conducted. The effect of hub fairing/pylon clearance on hub fairing/pylon mutual interference drag was examined in detail. Force and moment data are presented in tabular and graphical forms. The results indicate that hub fairings with a circular-arc upper surface and a flat lower surface yield maximum hub drag reduction; and clearance between the hub fairing and pylon induces high mutual-interference drag and diminishes the drag-reduction benefit obtained using a hub fairing with a flat lower surface. Test data show that symmetrical hub fairings with circular-arc surfaces generate 74 percent more interference drag than do cambered hub fairings with flat lower surfaces, at moderate negative angle of attack.

  20. Neuroanatomical differences in brain areas implicated in perceptual and other core features of autism revealed by cortical thickness analysis and voxel-based morphometry.

    PubMed

    Hyde, Krista L; Samson, Fabienne; Evans, Alan C; Mottron, Laurent

    2010-04-01

    Autism spectrum disorder is a complex neurodevelopmental variant thought to affect 1 in 166 [Fombonne (2003): J Autism Dev Disord 33:365-382]. Individuals with autism demonstrate atypical social interaction, communication, and repetitive behaviors, but can also present enhanced abilities, particularly in auditory and visual perception and nonverbal reasoning. Structural brain differences have been reported in autism, in terms of increased total brain volume (particularly in young children with autism), and regional gray/white matter differences in both adults and children with autism, but the reports are inconsistent [Amaral et al. (2008): Trends Neurosci 31:137-145]. These inconsistencies may be due to differences in diagnostic/inclusion criteria, and age and Intelligence Quotient of participants. Here, for the first time, we used two complementary magnetic resonance imaging techniques, cortical thickness analyses, and voxel-based morphometry (VBM), to investigate the neuroanatomical differences between a homogenous group of young adults with autism of average intelligence but delayed or atypical language development (often referred to as "high-functioning autism"), relative to a closely matched group of typically developing controls. The cortical thickness and VBM techniques both revealed regional structural brain differences (mostly in terms of gray matter increases) in brain areas implicated in social cognition, communication, and repetitive behaviors, and thus in each of the core atypical features of autism. Gray matter increases were also found in auditory and visual primary and associative perceptual areas. We interpret these results as the first structural brain correlates of atypical auditory and visual perception in autism, in support of the enhanced perceptual functioning model [Mottron et al. (2006): J Autism Dev Disord 36:27-43].

  1. Differential Responses to a Visual Self-Motion Signal in Human Medial Cortical Regions Revealed by Wide-View Stimulation

    PubMed Central

    Wada, Atsushi; Sakano, Yuichi; Ando, Hiroshi

    2016-01-01

    Vision is important for estimating self-motion, which is thought to involve optic-flow processing. Here, we investigated the fMRI response profiles in visual area V6, the precuneus motion area (PcM), and the cingulate sulcus visual area (CSv)—three medial brain regions recently shown to be sensitive to optic-flow. We used wide-view stereoscopic stimulation to induce robust self-motion processing. Stimuli included static, randomly moving, and coherently moving dots (simulating forward self-motion). We varied the stimulus size and the presence of stereoscopic information. A combination of univariate and multi-voxel pattern analyses (MVPA) revealed that fMRI responses in the three regions differed from each other. The univariate analysis identified optic-flow selectivity and an effect of stimulus size in V6, PcM, and CSv, among which only CSv showed a significantly lower response to random motion stimuli compared with static conditions. Furthermore, MVPA revealed an optic-flow specific multi-voxel pattern in the PcM and CSv, where the discrimination of coherent motion from both random motion and static conditions showed above-chance prediction accuracy, but that of random motion from static conditions did not. Additionally, while area V6 successfully classified different stimulus sizes regardless of motion pattern, this classification was only partial in PcM and was absent in CSv. This may reflect the known retinotopic representation in V6 and the absence of such clear visuospatial representation in CSv. We also found significant correlations between the strength of subjective self-motion and univariate activation in all examined regions except for primary visual cortex (V1). This neuro-perceptual correlation was significantly higher for V6, PcM, and CSv when compared with V1, and higher for CSv when compared with the visual motion area hMT+. Our convergent results suggest the significant involvement of CSv in self-motion processing, which may give rise to its

  2. Contextual Hub Analysis Tool (CHAT): A Cytoscape app for identifying contextually relevant hubs in biological networks

    PubMed Central

    Wiencko, Heather L.; Bernal-Llinares, Manuel; Bryan, Kenneth; Lynn, David J.

    2016-01-01

    Highly connected nodes (hubs) in biological networks are topologically important to the structure of the network and have also been shown to be preferentially associated with a range of phenotypes of interest. The relative importance of a hub node, however, can change depending on the biological context. Here, we report a Cytoscape app, the Contextual Hub Analysis Tool (CHAT), which enables users to easily construct and visualize a network of interactions from a gene or protein list of interest, integrate contextual information, such as gene expression or mass spectrometry data, and identify hub nodes that are more highly connected to contextual nodes (e.g. genes or proteins that are differentially expressed) than expected by chance. In a case study, we use CHAT to construct a network of genes that are differentially expressed in Dengue fever, a viral infection. CHAT was used to identify and compare contextual and degree-based hubs in this network. The top 20 degree-based hubs were enriched in pathways related to the cell cycle and cancer, which is likely due to the fact that proteins involved in these processes tend to be highly connected in general. In comparison, the top 20 contextual hubs were enriched in pathways commonly observed in a viral infection including pathways related to the immune response to viral infection. This analysis shows that such contextual hubs are considerably more biologically relevant than degree-based hubs and that analyses which rely on the identification of hubs solely based on their connectivity may be biased towards nodes that are highly connected in general rather than in the specific context of interest. Availability: CHAT is available for Cytoscape 3.0+ and can be installed via the Cytoscape App Store ( http://apps.cytoscape.org/apps/chat). PMID:27853512

  3. Contextual Hub Analysis Tool (CHAT): A Cytoscape app for identifying contextually relevant hubs in biological networks.

    PubMed

    Muetze, Tanja; Goenawan, Ivan H; Wiencko, Heather L; Bernal-Llinares, Manuel; Bryan, Kenneth; Lynn, David J

    2016-01-01

    Highly connected nodes (hubs) in biological networks are topologically important to the structure of the network and have also been shown to be preferentially associated with a range of phenotypes of interest. The relative importance of a hub node, however, can change depending on the biological context. Here, we report a Cytoscape app, the Contextual Hub Analysis Tool (CHAT), which enables users to easily construct and visualize a network of interactions from a gene or protein list of interest, integrate contextual information, such as gene expression or mass spectrometry data, and identify hub nodes that are more highly connected to contextual nodes (e.g. genes or proteins that are differentially expressed) than expected by chance. In a case study, we use CHAT to construct a network of genes that are differentially expressed in Dengue fever, a viral infection. CHAT was used to identify and compare contextual and degree-based hubs in this network. The top 20 degree-based hubs were enriched in pathways related to the cell cycle and cancer, which is likely due to the fact that proteins involved in these processes tend to be highly connected in general. In comparison, the top 20 contextual hubs were enriched in pathways commonly observed in a viral infection including pathways related to the immune response to viral infection. This analysis shows that such contextual hubs are considerably more biologically relevant than degree-based hubs and that analyses which rely on the identification of hubs solely based on their connectivity may be biased towards nodes that are highly connected in general rather than in the specific context of interest.

  4. Evolutionary and Physiological Importance of Hub Proteins

    PubMed Central

    Batada, Nizar N; Hurst, Laurence D; Tyers, Mike

    2006-01-01

    It has been claimed that proteins with more interaction partners (hubs) are both physiologically more important (i.e., less dispensable) and, owing to an assumed high density of binding sites, slow evolving. Not all analyses, however, support these results, probably because of biased and less-than reliable global protein interaction data. Here we provide the first examination of these issues using a comprehensive literature-curated dataset of well-substantiated protein interactions in Saccharomyces cerevisiae. Whereas use of less reliable yeast two-hybrid data alone can reject the possibility that local connectivity correlates with measures of dispensability, in higher quality datasets a relatively robust correlation is observed. In contrast, local connectivity does not correlate with the rate of protein evolution even in reliable datasets. This perhaps surprising lack of correlation with evolutionary rate appears in part to arise from the fact that hub proteins do not have a higher density of residues associated with binding. However, hub proteins do have at least one other set of unusual features, namely rapid turnover and regulation, as manifest in high mRNA decay rates and a large number of phosphorylation sites. This, we suggest, is an adaptation to minimize unwanted activation of pathways that might be mediated by adventitious binding to hubs, were they to actively persist longer than required at any given time point. We conclude that hub proteins are more important for cellular growth rate and under tight regulation but are not slow evolving. PMID:16839197

  5. Development of monofilar rotor hub vibration absorber

    NASA Technical Reports Server (NTRS)

    Duh, J.; Miao, W.

    1983-01-01

    A design and ground test program was conducted to study the performance of the monofilar absorber for vibration reduction on a four-bladed helicopter. A monofilar is a centrifugal tuned two degree-of-freedom rotor hub absorber that provides force attenuation at two frequencies using the same dynamic mass. Linear and non-linear analyses of the coupled monofilar/airframe system were developed to study tuning and attenuation characteristics. Based on the analysis, a design was fabricated and impact bench tests verified the calculated non-rotating natural frequencies and mode shapes. Performance characteristics were measured using a rotating absorber test facility. These tests showed significant attenuation of fixed-system 4P hub motions due to 3P inplane rotating-system hub forces. In addition, detuning effects of the 3P monofilar modal response were small due to the nonlinearities and tuning pin slippage. However, attenuation of 4P hub motions due to 5P inplane hub forces was poor. The performance of the 5P monofilar modal response was degraded by torsional motion of the dynamic mass relative to the support arm which resulted in binding of the dynamic components. Analytical design studies were performed to evaluate this torsional motion problem. An alternative design is proposed which may alleviate the torsional motion of the dynamic mass.

  6. Collaborative Data Analytics with DataHub.

    PubMed

    Bhardwaj, Anant; Karger, David; Subramanyam, Harihar; Deshpande, Amol; Madden, Sam; Wu, Eugene; Elmore, Aaron; Parameswaran, Aditya; Zhang, Rebecca

    2015-08-01

    While there have been many solutions proposed for storing and analyzing large volumes of data, all of these solutions have limited support for collaborative data analytics, especially given the many individuals and teams are simultaneously analyzing, modifying and exchanging datasets, employing a number of heterogeneous tools or languages for data analysis, and writing scripts to clean, preprocess, or query data. We demonstrate DataHub, a unified platform with the ability to load, store, query, collaboratively analyze, interactively visualize, interface with external applications, and share datasets. We will demonstrate the following aspects of the DataHub platform: (a) flexible data storage, sharing, and native versioning capabilities: multiple conference attendees can concurrently update the database and browse the different versions and inspect conflicts; (b) an app ecosystem that hosts apps for various data-processing activities: conference attendees will be able to effortlessly ingest, query, and visualize data using our existing apps; (c) thrift-based data serialization permits data analysis in any combination of 20+ languages, with DataHub as the common data store: conference attendees will be able to analyze datasets in R, Python, and Matlab, while the inputs and the results are still stored in DataHub. In particular, conference attendees will be able to use the DataHub notebook - an IPython-based notebook for analyzing data and storing the results of data analysis.

  7. Collaborative Data Analytics with DataHub

    PubMed Central

    Bhardwaj, Anant; Karger, David; Subramanyam, Harihar; Deshpande, Amol; Madden, Sam; Wu, Eugene; Elmore, Aaron; Parameswaran, Aditya; Zhang, Rebecca

    2015-01-01

    While there have been many solutions proposed for storing and analyzing large volumes of data, all of these solutions have limited support for collaborative data analytics, especially given the many individuals and teams are simultaneously analyzing, modifying and exchanging datasets, employing a number of heterogeneous tools or languages for data analysis, and writing scripts to clean, preprocess, or query data. We demonstrate DataHub, a unified platform with the ability to load, store, query, collaboratively analyze, interactively visualize, interface with external applications, and share datasets. We will demonstrate the following aspects of the DataHub platform: (a) flexible data storage, sharing, and native versioning capabilities: multiple conference attendees can concurrently update the database and browse the different versions and inspect conflicts; (b) an app ecosystem that hosts apps for various data-processing activities: conference attendees will be able to effortlessly ingest, query, and visualize data using our existing apps; (c) thrift-based data serialization permits data analysis in any combination of 20+ languages, with DataHub as the common data store: conference attendees will be able to analyze datasets in R, Python, and Matlab, while the inputs and the results are still stored in DataHub. In particular, conference attendees will be able to use the DataHub notebook — an IPython-based notebook for analyzing data and storing the results of data analysis. PMID:26844007

  8. Sound to Language: Different Cortical Processing for First and Second Languages in Elementary School Children as Revealed by a Large-Scale Study Using fNIRS

    PubMed Central

    Ojima, Shiro; Matsuba-Kurita, Hiroko; Dan, Ippeita; Tsuzuki, Daisuke; Katura, Takusige; Hagiwara, Hiroko

    2011-01-01

    A large-scale study of 484 elementary school children (6–10 years) performing word repetition tasks in their native language (L1-Japanese) and a second language (L2-English) was conducted using functional near-infrared spectroscopy. Three factors presumably associated with cortical activation, language (L1/L2), word frequency (high/low), and hemisphere (left/right), were investigated. L1 words elicited significantly greater brain activation than L2 words, regardless of semantic knowledge, particularly in the superior/middle temporal and inferior parietal regions (angular/supramarginal gyri). The greater L1-elicited activation in these regions suggests that they are phonological loci, reflecting processes tuned to the phonology of the native language, while phonologically unfamiliar L2 words were processed like nonword auditory stimuli. The activation was bilateral in the auditory and superior/middle temporal regions. Hemispheric asymmetry was observed in the inferior frontal region (right dominant), and in the inferior parietal region with interactions: low-frequency words elicited more right-hemispheric activation (particularly in the supramarginal gyrus), while high-frequency words elicited more left-hemispheric activation (particularly in the angular gyrus). The present results reveal the strong involvement of a bilateral language network in children’s brains depending more on right-hemispheric processing while acquiring unfamiliar/low-frequency words. A right-to-left shift in laterality should occur in the inferior parietal region, as lexical knowledge increases irrespective of language. PMID:21350046

  9. Multi-level characterization of human femoral cortices and their underlying osteocyte network reveal trends in quality of young, aged, osteoporotic and antiresorptive-treated bone.

    PubMed

    Milovanovic, Petar; Zimmermann, Elizabeth A; Riedel, Christoph; vom Scheidt, Annika; Herzog, Lydia; Krause, Matthias; Djonic, Danijela; Djuric, Marija; Püschel, Klaus; Amling, Michael; Ritchie, Robert O; Busse, Björn

    2015-03-01

    Characterization of bone's hierarchical structure in aging, disease and treatment conditions is imperative to understand the architectural and compositional modifications to the material and its mechanical integrity. Here, cortical bone sections from 30 female proximal femurs - a frequent fracture site - were rigorously assessed to characterize the osteocyte lacunar network, osteon density and patterns of bone matrix mineralization by backscatter-electron imaging and Fourier-transform infrared spectroscopy in relation to mechanical properties obtained by reference-point indentation. We show that young, healthy bone revealed the highest resistance to mechanical loading (indentation) along with higher mineralization and preserved osteocyte-lacunar characteristics. In contrast, aging and osteoporosis significantly alter bone material properties, where impairment of the osteocyte-lacunar network was evident through accumulation of hypermineralized osteocyte lacunae with aging and even more in osteoporosis, highlighting increased osteocyte apoptosis and reduced mechanical competence. But antiresorptive treatment led to fewer mineralized lacunae and fewer but larger osteons signifying rejuvenated bone. In summary, multiple structural and compositional changes to the bone material were identified leading to decay or maintenance of bone quality in disease, health and treatment conditions. Clearly, antiresorptive treatment reflected favorable effects on the multifunctional osteocytic cells that are a prerequisite for bone's structural, metabolic and mechanosensory integrity.

  10. Hub-activated signal transmission in complex networks

    NASA Astrophysics Data System (ADS)

    Jahnke, Sven; Memmesheimer, Raoul-Martin; Timme, Marc

    2014-03-01

    A wide range of networked systems exhibit highly connected nodes (hubs) as prominent structural elements. The functional roles of hubs in the collective nonlinear dynamics of many such networks, however, are not well understood. Here, we propose that hubs in neural circuits may activate local signal transmission along sequences of specific subnetworks. Intriguingly, in contrast to previous suggestions of the functional roles of hubs, here, not the hubs themselves, but nonhub subnetworks transfer the signals. The core mechanism relies on hubs and nonhubs providing activating feedback to each other. It may, thus, induce the propagation of specific pulse and rate signals in neuronal and other communication networks.

  11. Emerging Education Hubs: The Case of Singapore

    ERIC Educational Resources Information Center

    Sidhu, Ravinder; Ho, K.-C.; Yeoh, Brenda

    2011-01-01

    In anticipation of a globalising post-Fordist political economy, countries and universities are increasingly pursuing strategic transnational education and research alliances. This article analyses the Global Schoolhouse, a key education policy platform that aims to transform Singapore into a knowledge and innovation hub by establishing networks…

  12. Key Data on Music Education Hubs 2014

    ERIC Educational Resources Information Center

    Sharp, Caroline

    2015-01-01

    Music Education Hubs (MEHs) were created to provide access, opportunities and excellence in music education for all children and young people. A total of 123 MEHs were established and started work in 2012. The National Foundation for Educational Research (NFER) carried out secondary analysis of a survey conducted by Arts Council England in Autumn…

  13. Stieber Dynamometer Hub for Aircraft Propellers

    NASA Technical Reports Server (NTRS)

    Stieber, W

    1924-01-01

    The knowledge gained from previous experiments and reports was utilized for the construction of a dynamometer hub for 200 mkg (134.4 ft.-lb.) and 1200 kg (2646 lb.) thrust suited for a Liberty "12" engine. A reversing device is also described.

  14. IEEE 1394 Hub With Fault Containment

    NASA Technical Reports Server (NTRS)

    Paulitsch, Michael; Hall, Brendan; Driscoll, Kevin R.

    2009-01-01

    This innovation is designed to prevent a single end system communication node from negatively influencing the whole system s behavior so that the network system can still operate if an end node is faulty. Placing a hub (star) in the middle of the system prevents propagation of critical control information that other end systems would react to, like block reset messages.

  15. Cortical Clefts and Cortical Bumps: A Continuous Spectrum

    PubMed Central

    Furruqh, Farha; Thirunavukarasu, Suresh; Vivekandan, Ravichandran

    2016-01-01

    Cortical ‘clefts’ (schizencephaly) and cortical ‘bumps’ (polymicrogyria) are malformations arising due to defects in postmigrational development of neurons. They are frequently encountered together, with schizencephalic clefts being lined by polymicrogyria. We present the case of an eight-year-old boy who presented with seizures. Imaging revealed closed lip schizencephaly, polymicrogyria and a deep ‘incomplete’ cleft lined by polymicrogyria not communicating with the lateral ventricle. We speculate that hypoperfusion or ischaemic cortical injury during neuronal development may lead to a spectrum of malformations ranging from polymicrogyria to incomplete cortical clefts to schizencephaly. PMID:27630923

  16. The Regional Dimension of Education Hubs: Leading and Brokering Geopolitics

    ERIC Educational Resources Information Center

    Lee, Jack T.

    2015-01-01

    Several education hubs have emerged in the last decade in Asia and the Middle East. These ambitious policy initiatives share a common interest in cross-border higher education even though diverse rationales underpin their development. While some claim to be an international education hub, others claim to be a regional education hub or…

  17. 14 CFR 398.2 - Number and designation of hubs.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the United States. (b) How many hubs? (1) As a general matter, the Department will require service to... of three classifications: (1) A large hub is a place accounting for at least 1.00 percent of the total enplanements in the United States; (2) A medium hub is a place accounting for at least 0.25...

  18. The Regional Dimension of Education Hubs: Leading and Brokering Geopolitics

    ERIC Educational Resources Information Center

    Lee, Jack T.

    2015-01-01

    Several education hubs have emerged in the last decade in Asia and the Middle East. These ambitious policy initiatives share a common interest in cross-border higher education even though diverse rationales underpin their development. While some claim to be an international education hub, others claim to be a regional education hub or…

  19. Southwest Regional Climate Hub and California Subsidiary Hub assessment of climate change vulnerability and adaptation and mitigation strategies

    Treesearch

    Emile Elias; Caiti Steele; Kris Havstad; Kerri Steenwerth; Jeanne Chambers; Helena Deswood; Amber Kerr; Albert Rango; Mark Schwartz; Peter Stine; Rachel Steele

    2015-01-01

    This report is a joint effort of the Southwest Regional Climate Hub and the California Subsidiary Hub (Sub Hub). The Southwest Regional Climate Hub covers Arizona, California, Hawai‘i and the U.S. affiliated Pacific Islands, Nevada, New Mexico, and Utah and contains vast areas of western rangeland, forests, and high-value specialty crops (Figure 1). The California Sub...

  20. Distinct cortical and striatal actions of a β-arrestin-biased dopamine D2 receptor ligand reveal unique antipsychotic-like properties.

    PubMed

    Urs, Nikhil M; Gee, Steven M; Pack, Thomas F; McCorvy, John D; Evron, Tama; Snyder, Joshua C; Yang, Xiaobao; Rodriguiz, Ramona M; Borrelli, Emiliana; Wetsel, William C; Jin, Jian; Roth, Bryan L; O'Donnell, Patricio; Caron, Marc G

    2016-12-13

    The current dopamine (DA) hypothesis of schizophrenia postulates striatal hyperdopaminergia and cortical hypodopaminergia. Although partial agonists at DA D2 receptors (D2Rs), like aripiprazole, were developed to simultaneously target both phenomena, they do not effectively improve cortical dysfunction. In this study, we investigate the potential for newly developed β-arrestin2 (βarr2)-biased D2R partial agonists to simultaneously target hyper- and hypodopaminergia. Using neuron-specific βarr2-KO mice, we show that the antipsychotic-like effects of a βarr2-biased D2R ligand are driven through both striatal antagonism and cortical agonism of D2R-βarr2 signaling. Furthermore, βarr2-biased D2R agonism enhances firing of cortical fast-spiking interneurons. This enhanced cortical agonism of the biased ligand can be attributed to a lack of G-protein signaling and elevated expression of βarr2 and G protein-coupled receptor (GPCR) kinase 2 in the cortex versus the striatum. Therefore, we propose that βarr2-biased D2R ligands that exert region-selective actions could provide a path to develop more effective antipsychotic therapies.

  1. Distinct cortical and striatal actions of a β-arrestin–biased dopamine D2 receptor ligand reveal unique antipsychotic-like properties

    PubMed Central

    Urs, Nikhil M.; Gee, Steven M.; Pack, Thomas F.; McCorvy, John D.; Evron, Tama; Snyder, Joshua C.; Yang, Xiaobao; Rodriguiz, Ramona M.; Borrelli, Emiliana; Wetsel, William C.; Jin, Jian; Roth, Bryan L.; O’Donnell, Patricio; Caron, Marc G.

    2016-01-01

    The current dopamine (DA) hypothesis of schizophrenia postulates striatal hyperdopaminergia and cortical hypodopaminergia. Although partial agonists at DA D2 receptors (D2Rs), like aripiprazole, were developed to simultaneously target both phenomena, they do not effectively improve cortical dysfunction. In this study, we investigate the potential for newly developed β-arrestin2 (βarr2)-biased D2R partial agonists to simultaneously target hyper- and hypodopaminergia. Using neuron-specific βarr2-KO mice, we show that the antipsychotic-like effects of a βarr2-biased D2R ligand are driven through both striatal antagonism and cortical agonism of D2R-βarr2 signaling. Furthermore, βarr2-biased D2R agonism enhances firing of cortical fast-spiking interneurons. This enhanced cortical agonism of the biased ligand can be attributed to a lack of G-protein signaling and elevated expression of βarr2 and G protein-coupled receptor (GPCR) kinase 2 in the cortex versus the striatum. Therefore, we propose that βarr2-biased D2R ligands that exert region-selective actions could provide a path to develop more effective antipsychotic therapies. PMID:27911814

  2. Object vision to hand action in macaque parietal, premotor, and motor cortices

    PubMed Central

    Schaffelhofer, Stefan; Scherberger, Hansjörg

    2016-01-01

    Grasping requires translating object geometries into appropriate hand shapes. How the brain computes these transformations is currently unclear. We investigated three key areas of the macaque cortical grasping circuit with microelectrode arrays and found cooperative but anatomically separated visual and motor processes. The parietal area AIP operated primarily in a visual mode. Its neuronal population revealed a specialization for shape processing, even for abstract geometries, and processed object features ultimately important for grasping. Premotor area F5 acted as a hub that shared the visual coding of AIP only temporarily and switched to highly dominant motor signals towards movement planning and execution. We visualize these non-discrete premotor signals that drive the primary motor cortex M1 to reflect the movement of the grasping hand. Our results reveal visual and motor features encoded in the grasping circuit and their communication to achieve transformation for grasping. DOI: http://dx.doi.org/10.7554/eLife.15278.001 PMID:27458796

  3. What properties characterize the hub proteins of the protein-protein interaction network of Saccharomyces cerevisiae?

    PubMed Central

    Ekman, Diana; Light, Sara; Björklund, Åsa K; Elofsson, Arne

    2006-01-01

    Background Most proteins interact with only a few other proteins while a small number of proteins (hubs) have many interaction partners. Hub proteins and non-hub proteins differ in several respects; however, understanding is not complete about what properties characterize the hubs and set them apart from proteins of low connectivity. Therefore, we have investigated what differentiates hubs from non-hubs and static hubs (party hubs) from dynamic hubs (date hubs) in the protein-protein interaction network of Saccharomyces cerevisiae. Results The many interactions of hub proteins can only partly be explained by bindings to similar proteins or domains. It is evident that domain repeats, which are associated with binding, are enriched in hubs. Moreover, there is an over representation of multi-domain proteins and long proteins among the hubs. In addition, there are clear differences between party hubs and date hubs. Fewer of the party hubs contain long disordered regions compared to date hubs, indicating that these regions are important for flexible binding but less so for static interactions. Furthermore, party hubs interact to a large extent with each other, supporting the idea of party hubs as the cores of highly clustered functional modules. In addition, hub proteins, and in particular party hubs, are more often ancient. Finally, the more recent paralogs of party hubs are underrepresented. Conclusion Our results indicate that multiple and repeated domains are enriched in hub proteins and, further, that long disordered regions, which are common in date hubs, are particularly important for flexible binding. PMID:16780599

  4. Wind turbine rotor hub and teeter joint

    DOEpatents

    Coleman, Clint; Kurth, William T.; Jankowski, Joseph

    1994-10-11

    A rotor hub is provided for coupling a wind turbine rotor blade and a shaft. The hub has a yoke with a body which is connected to the shaft, and extension portions which are connected to teeter bearing blocks, each of which has an aperture. The blocks are connected to a saddle which envelops the rotor blade by one or two shafts which pass through the apertures in the bearing blocks. The saddle and blade are separated by a rubber interface which provides for distribution of stress over a larger portion of the blade. Two teeter control mechanisms, which may include hydraulic pistons and springs, are connected to the rotor blade and to the yoke at extension portions. These control mechanisms provide end-of-stroke damping, braking, and stiffness based on the teeter angle and speed of the blade.

  5. Functional Hubs in Mild Cognitive Impairment

    NASA Astrophysics Data System (ADS)

    Navas, Adrián; Papo, David; Boccaletti, Stefano; Del-Pozo, F.; Bajo, Ricardo; Maestú, Fernando; Martínez, J. H.; Gil, Pablo; Sendiña-Nadal, Irene; Buldú, Javier M.

    We investigate how hubs of functional brain networks are modified as a result of mild cognitive impairment (MCI), a condition causing a slight but noticeable decline in cognitive abilities, which sometimes precedes the onset of Alzheimer's disease. We used magnetoencephalography (MEG) to investigate the functional brain networks of a group of patients suffering from MCI and a control group of healthy subjects, during the execution of a short-term memory task. Couplings between brain sites were evaluated using synchronization likelihood, from which a network of functional interdependencies was constructed and the centrality, i.e. importance, of their nodes was quantified. The results showed that, with respect to healthy controls, MCI patients were associated with decreases and increases in hub centrality respectively in occipital and central scalp regions, supporting the hypothesis that MCI modifies functional brain network topology, leading to more random structures.

  6. Characteristics on hub networks of urban rail transit networks

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhua; Wang, Shuliang; Zhang, Zhaojun; Zou, Kuansheng; Shu, Zhan

    2016-04-01

    This paper proposes an approach to extract the hub networks from urban rail transit networks, and analyzes the characteristics of the hub networks. Minsk metro and Shanghai metro networks are given to illustrate the feasibility and effectiveness of the presented method in this paper. By simulations, we discover that the hub networks of urban rail transit networks possess small-world property and scale-free property. Meanwhile, this paper shows that the hub networks are completely different from the corresponding metro networks. Moreover, we find that the hub network is a hierarchical network, and the root of hub network corresponds to the transfer station of metro network which is passed by the most lines in metro network, and the root controls the main characteristics of hub network. In other words, the transfer station corresponding to this root plays the most important role in the urban rail transit networks.

  7. Extension of Goldstein's circulation function for optimal rotors with hub

    NASA Astrophysics Data System (ADS)

    Okulov, V. L.; Sørensen, J. N.; Shen, W. Z.

    2016-09-01

    The aerodynamic interaction or interference between rotor blades and hub body is usually very complicated, but some useful simplifications can be made by considering the hub with an infinite cylinder. Various attempts to find the optimum distribution of circulation by the lifting vortex lines method have been previously proposed to describe the blade interaction with the hub modeled by the infinite cylinder. In this case, the ideal distribution of bound circulation on the rotor blades is such that the shed vortex system in the hub-area is a set of helicoidal vortex sheets moving uniformly as if rigid, exactly as in the case where there is no influence of the streamtube deformations by the central hub-body. In the present investigation, we consider a more specific problem of the rotor-hub interaction where the initial flow streamtubes and the rotor slipstream submitted strong deformations at the nose-area of the semi-infinite hub.

  8. Information Hub of the Russian Virtual Observatory

    NASA Astrophysics Data System (ADS)

    Malkov, Oleg; Dluzhnevskaya, Olga; Kilpio, Elena; Kilpio, Alexander; Kovaleva, Dana

    The ultimate goal of the Russian Virtual Observatory (RVO) initiative is to provide every astronomer with on-line access to the rich volumes of data and metadata that have been and will continue to be produced by astronomical survey projects. The information hub of the RVO has a main goal of integrating resources of astronomical data accumulated in Russian observatories and institutions, and providing transparent access for scientific and educational purposes to the distributed information and data services that comprise its content.

  9. Cortico-cortical communication dynamics

    PubMed Central

    Roland, Per E.; Hilgetag, Claus C.; Deco, Gustavo

    2014-01-01

    In principle, cortico-cortical communication dynamics is simple: neurons in one cortical area communicate by sending action potentials that release glutamate and excite their target neurons in other cortical areas. In practice, knowledge about cortico-cortical communication dynamics is minute. One reason is that no current technique can capture the fast spatio-temporal cortico-cortical evolution of action potential transmission and membrane conductances with sufficient spatial resolution. A combination of optogenetics and monosynaptic tracing with virus can reveal the spatio-temporal cortico-cortical dynamics of specific neurons and their targets, but does not reveal how the dynamics evolves under natural conditions. Spontaneous ongoing action potentials also spread across cortical areas and are difficult to separate from structured evoked and intrinsic brain activity such as thinking. At a certain state of evolution, the dynamics may engage larger populations of neurons to drive the brain to decisions, percepts and behaviors. For example, successfully evolving dynamics to sensory transients can appear at the mesoscopic scale revealing how the transient is perceived. As a consequence of these methodological and conceptual difficulties, studies in this field comprise a wide range of computational models, large-scale measurements (e.g., by MEG, EEG), and a combination of invasive measurements in animal experiments. Further obstacles and challenges of studying cortico-cortical communication dynamics are outlined in this critical review. PMID:24847217

  10. Understanding farmers' preferences for artificial insemination services provided through dairy hubs.

    PubMed

    Omondi, I A; Zander, K K; Bauer, S; Baltenweck, I

    2017-04-01

    Africa has a shortage of animal products but increasing demand because of population growth, urbanisation and changing consumer patterns. Attempts to boost livestock production through the use of breeding technologies such as artificial insemination (AI) have been failing in many countries because costs have escalated and success rates have been relatively low. One example is Kenya, a country with a relatively large number of cows and a dairy industry model relevant to neighbouring countries. There, an innovative dairy marketing approach (farmer-owned collective marketing systems called dairy hubs) has been implemented to enhance access to dairy markets and dairy-related services, including breeding services such as AI. So far, the rate of participation in these dairy hubs has been slow and mixed. In order to understand this phenomenon better and to inform dairy-related development activities by the Kenyan government, we investigated which characteristics of AI services, offered through the dairy hubs, farmers prefer. To do so, we applied a choice experiment (CE), a non-market valuation technique, which allowed us to identify farmers' preferences for desired characteristics should more dairy hubs be installed in the future. This is the first study to use a CE to evaluate breeding services in Kenya and the results can complement findings of studies of breeding objectives and selection criteria. The results of the CE reveal that dairy farmers prefer to have AI services offered rather than having no service. Farmers prefer AI services to be available at dairy hubs rather than provided by private agents not affiliated to the hubs, to have follow-up services for pregnancy detections, and to use sexed semen rather than conventional semen. Farmers would further like some flexibility in payment systems which include input credit, and are willing to share the costs of any AI repeats that may need to occur. These results provide evidence of a positive attitude to AI services

  11. Does the central sulcus divide motor and sensory functions? Cortical mapping of human hand areas as revealed by electrical stimulation through subdural grid electrodes.

    PubMed

    Nii, Y; Uematsu, S; Lesser, R P; Gordon, B

    1996-02-01

    To clarify the exact anatomic relationship of electrically identified hand areas to the central sulcus, we constructed cortical surface renderings of magnetic resonance images (MRI) to locate the central sulcus accurately and measured the distances of stimulated points from the central sulcus and the Sylvian fissure. We obtained hand responses in 33 patients who underwent implantation of subdural grid electrodes for evaluation and surgical treatment of intractable epilepsy and analyzed these responses according to the presence of motor, sensory, mixed motor and sensory, and arrest responses. Hand motor responses occurred not only in the precentral gyrus but also in the postcentral gyrus, with great variability in superior-to-inferior distribution. Sensory responses also occurred in both the precentral and postcentral gyri with a distribution more ventral than that of motor responses. Mixed motor and sensory responses tended to be limited to the middle part of the central sulcus. Sites where electrical stimulation arrested simple hand repetitive voluntary movements occurred widely throughout the premotor and primary sensorimotor cortices. These data indicate a marked variability in the location of the human cortical hand area, and suggest that motor and sensory hand cortices overlap and are not divided in a simple manner by the central sulcus.

  12. Mirrored bilateral slow-wave cortical activity within local circuits revealed by fast bihemispheric voltage-sensitive dye imaging in anesthetized and awake mice.

    PubMed

    Mohajerani, Majid H; McVea, David A; Fingas, Matthew; Murphy, Timothy H

    2010-03-10

    Spontaneous slow-wave oscillations of neuronal membrane potential occur about once every second in the rodent cortex and may serve to shape the efficacy of evoked neuronal responses and consolidate memory during sleep. However, whether these oscillations reflect the entrainment of all cortical regions via propagating waves or whether they exhibit regional and temporal heterogeneity that reflects processing in local cortical circuits is unknown. Using voltage-sensitive dye (VSD) imaging within an adult C57BL/6J mouse cross-midline large craniotomy preparation, we recorded this depolarizing activity across most of both cortical hemispheres simultaneously in both anesthetized and quiet awake animals. Spontaneous oscillations in the VSD signal were highly synchronized between hemispheres, and acallosal I/LnJ mice indicated that synchrony depended on the corpus callosum. In both anesthetized and awake mice (recovered from anesthesia), the oscillations were not necessarily global changes in activity state but were made up of complex local patterns characterized by multiple discrete peaks that were unevenly distributed across cortex. Although the local patterns of depolarizing activity were complex and changed over tens of milliseconds, they were faithfully mirrored in both hemispheres in mice with an intact corpus callosum, to perhaps ensure parallel modification of related circuits in both hemispheres. We conclude that within global rhythms of spontaneous activity are complex events that reflect orchestrated processing within local cortical circuits.

  13. Extraversion modulates functional connectivity hubs of resting-state brain networks.

    PubMed

    Pang, Yajing; Cui, Qian; Duan, Xujun; Chen, Heng; Zeng, Ling; Zhang, Zhiqiang; Lu, Guangming; Chen, Huafu

    2015-11-14

    Personality dimension extraversion describes individual differences in social behaviour and socio-emotional functioning. The intrinsic functional connectivity patterns of the brain are reportedly associated with extraversion. However, whether or not extraversion is associated with functional hubs warrants clarification. Functional hubs are involved in the rapid integration of neural processing, and their dysfunction contributes to the development of neuropsychiatric disorders. In this study, we employed the functional connectivity density (FCD) method for the first time to distinguish the energy-efficient hubs associated with extraversion. The resting-state functional magnetic resonance imaging data of 71 healthy subjects were used in the analysis. Short-range FCD was positively correlated with extraversion in the left cuneus, revealing a link between the local functional activity of this region and extraversion in risk-taking. Long-range FCD was negatively correlated with extraversion in the right superior frontal gyrus and the inferior frontal gyrus. Seed-based resting-state functional connectivity (RSFC) analyses revealed that a decreased long-range FCD in individuals with high extraversion scores showed a low long-range functional connectivity pattern between the medial and dorsolateral prefrontal cortex, middle temporal gyrus, and anterior cingulate cortex. This result suggests that decreased RSFC patterns are responsible for self-esteem, self-evaluation, and inhibitory behaviour system that account for the modulation and shaping of extraversion. Overall, our results emphasize specific brain hubs, and reveal long-range functional connections in relation to extraversion, thereby providing a neurobiological basis of extraversion.

  14. Preservation of structural brain network hubs is associated with less severe post-stroke aphasia.

    PubMed

    Gleichgerrcht, Ezequiel; Kocher, Madison; Nesland, Travis; Rorden, Chris; Fridriksson, Julius; Bonilha, Leonardo

    2015-01-01

    Post-stroke aphasia is typically associated with ischemic damage to cortical areas or with loss of connectivity among spared brain regions. It remains unclear whether the participation of spared brain regions as networks hubs affects the severity of aphasia. We evaluated language performance and magnetic resonance imaging from 44 participants with chronic aphasia post-stroke. The individual structural brain connectomes were constructed from diffusion tensor. Hub regions were defined in accordance with the rich club classification and studied in relation with language performance. Number of remaining left hemisphere rich club nodes was associated with aphasia, including comprehension, repetition and naming sub-scores. Importantly, among participants with relative preservation of regions of interest for language, aphasia severity was lessened if the region was not only spared, but also participated in the remaining network as a rich club node: Brodmann area (BA) 44/45 - repetition (p = 0.009), BA 39 - repetition (p = 0.045) and naming (p <  0.01), BA 37 - fluency (p <  0.001), comprehension (p = 0.025), repetition (p <  0.001) and naming (p <  0.001). Disruption of language network structural hubs is directly associated with aphasia severity after stroke.

  15. Differential cortical laminar structure revealed by NeuN immunostaining and myeloarchitecture between sulcal and gyral regions independent of sexual dimorphisms in the ferret cerebrum.

    PubMed

    Horiuchi-Hirose, Miwa; Sawada, Kazuhiko

    2016-08-01

    The purpose of this study was to quantitatively clarify differences in laminar structure and myeloarchitecture of sulcal and gyral regions of the cerebral cortex of ferrets. Histological sections of cerebrum from male and female ferrets at postnatal day 90 were made at the coronal plane, and were immunostained with anti-NeuN or anti-myelin basic protein (MBP). Thickness was estimated in the entire depth or three strata, that is, layer I, outer (layers II-III) and inner (layers IV-VI) strata of the neocortex in representative five sulcal and seven gyral regions. As with the entire cortical depth, outer and inner strata were significantly thinner in the sulcal bottoms than in the gyral crowns, whereas layer I had about twofold greater thickness in the sulcal bottoms. However, thicknesses of the entire cortical depth and each cortical stratum were not statistically different among five sulcal regions or seven gyral regions examined. By MBP immunostaining, myelin fibers ran tangentially through the superficial regions of layer I in gyral crowns. Those fibers were relatively denser in gyri of frontal and temporal regions, and relatively sparse in gyri of parietal and occipital regions, although their density in any gyri was not different between sexes. These results show a differential laminar structure and myeloarchitecture between the sulcal and gyral regions of the ferret cerebral cortex present in both sexes. Myelination of layer I tangential fibers varied among primary gyri and was weaker in phylogenetically higher-order cortical gyri. Anat Rec, 299:1003-1011, 2016. © 2016 Wiley Periodicals, Inc.

  16. Centrality of prefrontal and motor preparation cortices to Tourette Syndrome revealed by meta-analysis of task-based neuroimaging studies.

    PubMed

    Polyanska, Liliana; Critchley, Hugo D; Rae, Charlotte L

    2017-01-01

    Tourette Syndrome (TS) is a neurodevelopmental condition characterized by chronic multiple tics, which are experienced as compulsive and 'unwilled'. Patients with TS can differ markedly in the frequency, severity, and bodily distribution of tics. Moreover, there are high comorbidity rates with attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD), anxiety disorders, and depression. This complex clinical profile may account for apparent variability of findings across neuroimaging studies that connect neural function to cognitive and motor behavior in TS. Here we crystalized information from neuroimaging regarding the functional circuitry of TS, and furthermore, tested specifically for neural determinants of tic severity, by applying activation likelihood estimation (ALE) meta-analyses to neuroimaging (activation) studies of TS. Fourteen task-based studies (13 fMRI and one H2O-PET) met rigorous inclusion criteria. These studies, encompassing 25 experiments and 651 participants, tested for differences between TS participants and healthy controls across cognitive, motor, perceptual and somatosensory domains. Relative to controls, TS participants showed distributed differences in the activation of prefrontal (inferior, middle, and superior frontal gyri), anterior cingulate, and motor preparation cortices (lateral premotor cortex and supplementary motor area; SMA). Differences also extended into sensory (somatosensory cortex and the lingual gyrus; V4); and temporo-parietal association cortices (posterior superior temporal sulcus, supramarginal gyrus, and retrosplenial cortex). Within TS participants, tic severity (reported using the Yale Global Tic Severity Scale; YGTSS) selectively correlated with engagement of SMA, precentral gyrus, and middle frontal gyrus across tasks. The dispersed involvement of multiple cortical regions with differences in functional reactivity may account for heterogeneity in the symptomatic expression of TS and its

  17. WHAT IS CONTROLLING THE FRAGMENTATION IN THE INFRARED DARK CLOUD G14.225–0.506?: DIFFERENT LEVELS OF FRAGMENTATION IN TWIN HUBS

    SciTech Connect

    Busquet, Gemma; Girart, Josep Miquel; Palau, Aina; Liu, Hauyu Baobab; Ho, Paul T. P.; Zhang, Qizhou; De Gregorio-Monsalvo, Itziar; Pillai, Thushara; Anglada, Guillem

    2016-03-20

    We present observations of the 1.3 mm continuum emission toward hub-N and hub-S of the infrared dark cloud G14.225–0.506 carried out with the Submillimeter Array, together with observations of the dust emission at 870 and 350 μm obtained with APEX and CSO telescopes. The large-scale dust emission of both hubs consists of a single peaked clump elongated in the direction of the associated filament. At small scales, the SMA images reveal that both hubs fragment into several dust condensations. The fragmentation level was assessed under the same conditions and we found that hub-N presents 4 fragments while hub-S is more fragmented, with 13 fragments identified. We studied the density structure by means of a simultaneous fit of the radial intensity profile at 870 and 350 μm and the spectral energy distribution adopting a Plummer-like function to describe the density structure. The parameters inferred from the model are remarkably similar in both hubs, suggesting that density structure could not be responsible for determining the fragmentation level. We estimated several physical parameters, such as the level of turbulence and the magnetic field strength, and we found no significant differences between these hubs. The Jeans analysis indicates that the observed fragmentation is more consistent with thermal Jeans fragmentation compared with a scenario in which turbulent support is included. The lower fragmentation level observed in hub-N could be explained in terms of stronger UV radiation effects from a nearby H ii region, evolutionary effects, and/or stronger magnetic fields at small scales, a scenario that should be further investigated.

  18. Spontaneous Decoding of the Timing and Content of Human Object Perception from Cortical Surface Recordings Reveals Complementary Information in the Event-Related Potential and Broadband Spectral Change

    PubMed Central

    Miller, Kai J.; Schalk, Gerwin; Hermes, Dora; Ojemann, Jeffrey G.; Rao, Rajesh P. N.

    2016-01-01

    The link between object perception and neural activity in visual cortical areas is a problem of fundamental importance in neuroscience. Here we show that electrical potentials from the ventral temporal cortical surface in humans contain sufficient information for spontaneous and near-instantaneous identification of a subject’s perceptual state. Electrocorticographic (ECoG) arrays were placed on the subtemporal cortical surface of seven epilepsy patients. Grayscale images of faces and houses were displayed rapidly in random sequence. We developed a template projection approach to decode the continuous ECoG data stream spontaneously, predicting the occurrence, timing and type of visual stimulus. In this setting, we evaluated the independent and joint use of two well-studied features of brain signals, broadband changes in the frequency power spectrum of the potential and deflections in the raw potential trace (event-related potential; ERP). Our ability to predict both the timing of stimulus onset and the type of image was best when we used a combination of both the broadband response and ERP, suggesting that they capture different and complementary aspects of the subject’s perceptual state. Specifically, we were able to predict the timing and type of 96% of all stimuli, with less than 5% false positive rate and a ~20ms error in timing. PMID:26820899

  19. Nonlinear growth: an origin of hub organization in complex networks

    PubMed Central

    Kaiser, Marcus

    2017-01-01

    Many real-world networks contain highly connected nodes called hubs. Hubs are often crucial for network function and spreading dynamics. However, classical models of how hubs originate during network development unrealistically assume that new nodes attain information about the connectivity (for example the degree) of existing nodes. Here, we introduce hub formation through nonlinear growth where the number of nodes generated at each stage increases over time and new nodes form connections independent of target node features. Our model reproduces variation in number of connections, hub occurrence time, and rich-club organization of networks ranging from protein–protein, neuronal and fibre tract brain networks to airline networks. Moreover, nonlinear growth gives a more generic representation of these networks compared with previous preferential attachment or duplication–divergence models. Overall, hub creation through nonlinear network expansion can serve as a benchmark model for studying the development of many real-world networks. PMID:28405356

  20. Future of Colombo Airport (CMB) as an Airline Hub

    NASA Technical Reports Server (NTRS)

    Jayalath, J. T. D.; Bandara, J. M. S. J.

    2001-01-01

    Aviation throughout the world has seen profound changes within the last two decades. Today more and more airports are looking for hub operations. However, as the success of hub operation would depend on a number of parameters such as geographic location, route network, facilities available, passengers' acceptance etc., not all airports would be able to operate as successful hubs. This paper investigates the possibility for (he Bandaranayake international airport, Colombo, Sri Lanka (CMB) to emerge as a hub airport in the South Asian region. It is found that CMB is situated in a geographically advantageous position in the region with respect to the airline route network. Comparison of travel distances between CMB and prominent O-D pairs and evaluation of airline schedules at relevant established hub airports indicates that CMB could operate as a directional hub serving the South Asian market if the number of destinations with daily flights could be increased.

  1. Technology transfer hub for pandemic influenza vaccine.

    PubMed

    Friede, M; Serdobova, I; Palkonyay, L; Kieny, M P

    2009-01-29

    Increase of influenza vaccine production capacity in developing countries has been identified as an important element of global pandemic preparedness. Nevertheless, technology transfer for influenza vaccine production to developing country vaccine manufacturers has proven difficult because of lack of interested technology providers. As an alternative to an individual provider-recipient relationship, a technology and training platform (a "hub") for a generic non-proprietary process was established at a public sector European manufacturer's site. The conditions for setting up such a platform and the potential applicability of this model to other biologicals are discussed.

  2. TSHZ3 deletion causes an autism syndrome and defects in cortical projection neurons

    PubMed Central

    Andrieux, Joris; Roubertoux, Pierre L.; Metwaly, Mehdi; Jacq, Bernard; Fatmi, Ahmed; Had-Aissouni, Laurence; Kwan, Kenneth Y.; Salin, Pascal; Carlier, Michèle; Liedén, Agne; Rudd, Eva; Shinawi, Marwan; Vincent-Delorme, Catherine; Cuisset, Jean-Marie; Lemaitre, Marie-Pierre; Abderrehamane, Fatimetou; Duban, Bénédicte; Lemaitre, Jean-François; Woolf, Adrian S.; Bockenhauer, Detlef; Severac, Dany; Dubois, Emeric; Zhu, Ying; Sestan, Nenad; Garratt, Alistair N.; Kerkerian-Le Goff, Lydia; Fasano, Laurent

    2016-01-01

    TSHZ3, which encodes a zinc-finger transcription factor, was recently positioned as a hub gene in a module of genes with the highest expression in the developing human neocortex, but its functions remained unknown. Here, we identify TSHZ3 as the critical region for a syndrome associated with heterozygous deletions at 19q12q13.11, which includes autism spectrum disorder (ASD). In Tshz3 null mice, differentially expressed genes include layer-specific markers of cerebral cortical projection neurons (CPNs) and their human orthologues are strongly associated with ASD. Furthermore, mice heterozygous for Tshz3 deletion show functional changes at synapses established by CPNs and exhibit core ASD-like behavioral abnormalities. These findings reveal essential roles for Tshz3 in CPN development and function, whose alterations can account for ASD in the newly-defined TSHZ3 deletion syndrome. PMID:27668656

  3. Market hub technology in the domestic natural gas distribution system. [Natural gas market center or hub

    SciTech Connect

    Glicken, J.

    1992-09-01

    This document describes a panel discussion held on March 18, 1992 as part of a conference entitled Market Hub Technology'' . The purpose of the conference was to stimulate dialogue among various segments of the natural gas industry on the technology limits of an economic policy issue that has the potential to significantly alter the structure and functioning of the natural gas industry. Attendees included key US gas industry representatives, Federal Energy Regulatory Commission (FERC) commissioners, and others. The conference explored the concept of market centers, or hubs, and related technologies. It covered the technology currently available for the establishment of an integrated system of physical market hubs, and explored technology requirements for the further development of useful and efficient hubs. The discussion identified two primary barriers to the acceptance and implementation of a market center distribution system for natural gas. The first barrier is the potential change in the configuration of the market such a system would introduce and the resistance various industry segments would mount to such change. The second is the lack of industry standardization in the physical and business infrastructures.

  4. Dynamic hub load predicts cognitive decline after resective neurosurgery.

    PubMed

    Carbo, Ellen W S; Hillebrand, Arjan; van Dellen, Edwin; Tewarie, Prejaas; de Witt Hamer, Philip C; Baayen, Johannes C; Klein, Martin; Geurts, Jeroen J G; Reijneveld, Jaap C; Stam, Cornelis J; Douw, Linda

    2017-02-07

    Resective neurosurgery carries the risk of postoperative cognitive deterioration. The concept of 'hub (over)load', caused by (over)use of the most important brain regions, has been theoretically postulated in relation to symptomatology and neurological disease course, but lacks experimental confirmation. We investigated functional hub load and postsurgical cognitive deterioration in patients undergoing lesion resection. Patients (n = 28) underwent resting-state magnetoencephalography and neuropsychological assessments preoperatively and 1-year after lesion resection. We calculated stationary hub load score (SHub) indicating to what extent brain regions linked different subsystems; high SHub indicates larger processing pressure on hub regions. Dynamic hub load score (DHub) assessed its variability over time; low values, particularly in combination with high SHub values, indicate increased load, because of consistently high usage of hub regions. Hypothetically, increased SHub and decreased DHub relate to hub overload and thus poorer/deteriorating cognition. Between time points, deteriorating verbal memory performance correlated with decreasing upper alpha DHub. Moreover, preoperatively low DHub values accurately predicted declining verbal memory performance. In summary, dynamic hub load relates to cognitive functioning in patients undergoing lesion resection: postoperative cognitive decline can be tracked and even predicted using dynamic hub load, suggesting it may be used as a prognostic marker for tailored treatment planning.

  5. Dynamic hub load predicts cognitive decline after resective neurosurgery

    PubMed Central

    Carbo, Ellen W. S.; Hillebrand, Arjan; van Dellen, Edwin; Tewarie, Prejaas; de Witt Hamer, Philip C.; Baayen, Johannes C.; Klein, Martin; Geurts, Jeroen J. G.; Reijneveld, Jaap C.; Stam, Cornelis J.; Douw, Linda

    2017-01-01

    Resective neurosurgery carries the risk of postoperative cognitive deterioration. The concept of ‘hub (over)load’, caused by (over)use of the most important brain regions, has been theoretically postulated in relation to symptomatology and neurological disease course, but lacks experimental confirmation. We investigated functional hub load and postsurgical cognitive deterioration in patients undergoing lesion resection. Patients (n = 28) underwent resting-state magnetoencephalography and neuropsychological assessments preoperatively and 1-year after lesion resection. We calculated stationary hub load score (SHub) indicating to what extent brain regions linked different subsystems; high SHub indicates larger processing pressure on hub regions. Dynamic hub load score (DHub) assessed its variability over time; low values, particularly in combination with high SHub values, indicate increased load, because of consistently high usage of hub regions. Hypothetically, increased SHub and decreased DHub relate to hub overload and thus poorer/deteriorating cognition. Between time points, deteriorating verbal memory performance correlated with decreasing upper alpha DHub. Moreover, preoperatively low DHub values accurately predicted declining verbal memory performance. In summary, dynamic hub load relates to cognitive functioning in patients undergoing lesion resection: postoperative cognitive decline can be tracked and even predicted using dynamic hub load, suggesting it may be used as a prognostic marker for tailored treatment planning. PMID:28169349

  6. A parametric study of harmonic rotor hub loads

    NASA Technical Reports Server (NTRS)

    He, Chengjian

    1993-01-01

    A parametric study of vibratory rotor hub loads in a nonrotating system is presented. The study is based on a CAMRAD/JA model constructed for the GBH (Growth Version of Blackhawk Helicopter) Mach-scaled wind tunnel rotor model with high blade twist (-16 deg). The theoretical hub load predictions are validated by correlation with available measured data. Effects of various blade aeroelastic design changes on the harmonic nonrotating frame hub loads at both low and high forward flight speeds are investigated. The study aims to illustrate some of the physical mechanisms for change in the harmonic rotor hub loads due to blade design variations.

  7. Cortical Control of Zona Incerta

    PubMed Central

    Barthó, Péter; Slézia, Andrea; Varga, Viktor; Bokor, Hajnalka; Pinault, Didier; Buzsáki, György; Acsády, László

    2009-01-01

    The zona incerta (ZI) is at the crossroad of almost all major ascending and descending fiber tracts and targets numerous brain centers from the thalamus to the spinal cord. Effective ascending drive of ZI cells has been described, but the role of descending cortical signals in patterning ZI activity is unknown. Cortical control over ZI function was examined during slow cortical waves (1-3 Hz), paroxysmal high-voltage spindles (HVSs), and 5-9 Hz oscillations in anesthetized rats. In all conditions, rhythmic cortical activity significantly altered the firing pattern of ZI neurons recorded extracellularly and labeled with the juxtacellular method. During slow oscillations, the majority of ZI neurons became synchronized to the depth-negative phase (“up state”) of the cortical waves to a degree comparable to thalamocortical neurons. During HVSs, ZI cells displayed highly rhythmic activity in tight synchrony with the cortical oscillations. ZI neurons responded to short epochs of cortical 5-9 Hz oscillations, with a change in the interspike interval distribution and with an increase in spectral density in the 5-9 Hz band as measured by wavelet analysis. Morphological reconstruction revealed that most ZI cells have mediolaterally extensive dendritic trees and very long dendritic segments. Cortical terminals established asymmetrical synapses on ZI cells with very long active zones. These data suggest efficient integration of widespread cortical signals by single ZI neurons and strong cortical drive. We propose that the efferent GABAergic signal of ZI neurons patterned by the cortical activity can play a critical role in synchronizing thalamocortical and brainstem rhythms. PMID:17301175

  8. Comparison of cortical and white matter traumatic brain injury models reveals differential effects in the subventricular zone and divergent Sonic hedgehog signaling pathways in neuroblasts and oligodendrocyte progenitors.

    PubMed

    Mierzwa, Amanda J; Sullivan, Genevieve M; Beer, Laurel A; Ahn, Sohyun; Armstrong, Regina C

    2014-01-01

    The regenerative capacity of the central nervous system must be optimized to promote repair following traumatic brain injury (TBI) and may differ with the site and form of damage. Sonic hedgehog (Shh) maintains neural stem cells and promotes oligodendrogenesis. We examined whether Shh signaling contributes to neuroblast (doublecortin) or oligodendrocyte progenitor (neural/glial antigen 2 [NG2]) responses in two distinct TBI models. Shh-responsive cells were heritably labeled in vivo using Gli1-CreER(T2);R26-YFP bitransgenic mice with tamoxifen administration on Days 2 and 3 post-TBI. Injury to the cerebral cortex was produced with mild controlled cortical impact. Yellow fluorescent protein (YFP) cells decreased in cortical lesions. Total YFP cells increased in the subventricular zone (SVZ), indicating Shh pathway activation in SVZ cells, including doublecortin-labeled neuroblasts. The alternate TBI model produced traumatic axonal injury in the corpus callosum. YFP cells decreased within the SVZ and were rarely double labeled as NG2 progenitors. NG2 progenitors increased in the cortex, with a similar pattern in the corpus callosum. To further test the potential of NG2 progenitors to respond through Shh signaling, Smoothened agonist was microinjected into the corpus callosum to activate Shh signaling. YFP cells and NG2 progenitors increased in the SVZ but were not double labeled. This result indicates that either direct Smoothened activation in NG2 progenitors does not signal through Gli1 or that Smoothened agonist acts indirectly to increase NG2 progenitors. Therefore, in all conditions, neuroblasts exhibited differential Shh pathway utilization compared with oligodendrocyte progenitors. Notably, cortical versus white matter damage from TBI produced opposite responses of Shh-activated cells within the SVZ.

  9. Auditory processing in schizophrenia during the middle latency period (10–50 ms): high-density electrical mapping and source analysis reveal subcortical antecedents to early cortical deficits

    PubMed Central

    Leavitt, Victoria M.; Molholm, Sophie; Ritter, Walter; Shpaner, Marina; Foxe, John J.

    2007-01-01

    Introduction Auditory sensory processing dysfunction is a core component of schizophrenia, with deficits occurring at 50 ms post-stimulus firmly established in the literature. Given that the initial afference of primary auditory cortex occurs at least 35 ms earlier, however, an essential question remains: how early in sensory processing do such deficits arise, and do they occur during initial cortical afference or earlier, which would implicate subcortical auditory dysfunction. Objective To establish the onset of the earliest deficits in auditory processing, we examined the time window demarcating the transition from subcortical to cortical processing: 10 ms to 50 ms during the so-called middle latency responses (MLRs). These remain to be adequately characterized in patients with schizophrenia. Methods We recorded auditory evoked potentials (AEPs) to simple tone-pips from 15 control subjects and 21 medicated patients with longer-term schizophrenia or schizoaffective disorder (illness duration 16 yr, standard deviation [SD] 9.4 yr), using high-density electrical scalp recordings. Between-group analyses assessed the integrity of the MLRs across groups. In addition, 2 source-localization models were conducted to address whether a distinction between subcortical and cortical generators of the MLRs can be made and whether evidence for differential dorsal and ventral pathway contributions to auditory processing deficits can be established. Results Robust auditory processing deficits were found for patients as early as 15 ms. Evidence for subcortical generators of the earliest MLR component (P20) was provided by source analysis. Topographical mapping and source localization also pointed to greater decrements in processing in the dorsal auditory pathway of patients, providing support for a theory of pervasive deficits that are organized along the lines of a dorsal–ventral distinction. Conclusions Auditory sensory dysfunction in schizophrenia begins extremely early in

  10. Evaluation of VSAERO in prediction of aerodynamic characteristics of helicopter hub fairings

    NASA Technical Reports Server (NTRS)

    Louie, Alexander

    1989-01-01

    A low-order panel code, VSAERO, was used to predict the aerodynamic characteristics of helicopter hub fairings. Since the simulation of this kind of bluff body by VSAERO was not documented before, the VSAERO solutions were correlated with experimental data to establish their validity. The validation process revealed that simulation of the aerodynamic environment around a hub fairing was sensitive to several modeling parameters. Some of these parameters are body and wake panels arrangement, streamwise and spanwise separation location, and the most prominent one-the wake modeling. Three wake models were used: regular wake, separated wake, and jet model. The regular wake is a wake with negligible thickness (thin wake). It is represented by a single vortex sheet. The separated wake and the jet model in the present application are wakes with finite thickness (thick wake). They consist of a vortex sheet enclosing a region of low-energy flow. The results obtained with the reqular wake were marginally acceptable for sharp-edged hub fairings. For all other cases under consideration, the jet model results correlated slightly better. The separated wake, which seemed to be the most appropriate model, caused the solution to diverge. While the regular wake was straight-forward to apply in simulations, the jet model was not. It requires the user to provide information about the doublet strength gradient on wake panels by guessing the efflux velocities at the wake shedding location. In summary, VSAERO neither predicts accurately the aerodynamic characteristics of helicopter hub fairings nor was cost effective.

  11. "Scrub the hub": cleaning duration and reduction in bacterial load on central venous catheters.

    PubMed

    Simmons, Sarah; Bryson, Celestina; Porter, Susan

    2011-01-01

    This article reports the results of a study on the effect of alcohol disinfection duration on bacterial load on catheter hubs. Three different levels of disinfection (3, 10, and 15 seconds) were analyzed as well as a positive and negative control. All hubs with the exception of the negative controls were contaminated with a 10 bacterial solution and allowed to dry for 24 hours. Through each hub, 1 mL of sterile saline was flushed; a 10-μL calibrated loop was used to plate the flush onto blood agar. Colony counts were performed on the plates after a 24-hour incubation period. Results revealed that the 3 different levels of disinfection duration were not found to differ significantly in reduction in bacterial load. The duration of disinfection did not significantly change the bacterial load on the hub. However, any disinfection duration significantly decreased the bacterial load as compared to the positive control. A larger study would likely detect a significant result among the disinfections.

  12. Changed Hub and Corresponding Functional Connectivity of Subgenual Anterior Cingulate Cortex in Major Depressive Disorder.

    PubMed

    Wu, Huawang; Sun, Hui; Xu, Jinping; Wu, Yan; Wang, Chao; Xiao, Jing; She, Shenglin; Huang, Jianwei; Zou, Wenjin; Peng, Hongjun; Lu, Xiaobing; Huang, Guimao; Jiang, Tianzi; Ning, Yuping; Wang, Jiaojian

    2016-01-01

    Major depressive disorder (MDD) is one of the most prevalent mental disorders. In the brain, the hubs of the brain network play a key role in integrating and transferring information between different functional modules. However, whether the changed pattern in functional network hubs contributes to the onset of MDD remains unclear. Using resting-state functional magnetic resonance imaging (rs-fMRI) and graph theory methods, we investigated whether alterations of hubs can be detected in MDD. First, we constructed the whole-brain voxel-wise functional networks and calculated a functional connectivity strength (FCS) map in each subject in 34 MDD patients and 34 gender-, age- and education level-matched healthy controls (HCs). Next, the two-sample t-test was applied to compare the FCS maps between HC and MDD patients and identified significant decrease of FCS in subgenual anterior cingulate cortex (sgACC) in MDD patients. Subsequent functional connectivity analyses of sgACC showed disruptions in functional connectivity with posterior insula, middle and inferior temporal gyrus, lingual gyrus and cerebellum in MDD patients. Furthermore, the changed FCS of sgACC and functional connections to sgACC were significantly correlated with the Hamilton Depression Rating Scale (HDRS) scores in MDD patients. The results of the present study revealed the abnormal hub of sgACC and its corresponding disrupted frontal-limbic-visual cognitive-cerebellum functional networks in MDD. These findings may provide a new insight for the diagnosis and treatment of MDD.

  13. Changed Hub and Corresponding Functional Connectivity of Subgenual Anterior Cingulate Cortex in Major Depressive Disorder

    PubMed Central

    Wu, Huawang; Sun, Hui; Xu, Jinping; Wu, Yan; Wang, Chao; Xiao, Jing; She, Shenglin; Huang, Jianwei; Zou, Wenjin; Peng, Hongjun; Lu, Xiaobing; Huang, Guimao; Jiang, Tianzi; Ning, Yuping; Wang, Jiaojian

    2016-01-01

    Major depressive disorder (MDD) is one of the most prevalent mental disorders. In the brain, the hubs of the brain network play a key role in integrating and transferring information between different functional modules. However, whether the changed pattern in functional network hubs contributes to the onset of MDD remains unclear. Using resting-state functional magnetic resonance imaging (rs-fMRI) and graph theory methods, we investigated whether alterations of hubs can be detected in MDD. First, we constructed the whole-brain voxel-wise functional networks and calculated a functional connectivity strength (FCS) map in each subject in 34 MDD patients and 34 gender-, age- and education level-matched healthy controls (HCs). Next, the two-sample t-test was applied to compare the FCS maps between HC and MDD patients and identified significant decrease of FCS in subgenual anterior cingulate cortex (sgACC) in MDD patients. Subsequent functional connectivity analyses of sgACC showed disruptions in functional connectivity with posterior insula, middle and inferior temporal gyrus, lingual gyrus and cerebellum in MDD patients. Furthermore, the changed FCS of sgACC and functional connections to sgACC were significantly correlated with the Hamilton Depression Rating Scale (HDRS) scores in MDD patients. The results of the present study revealed the abnormal hub of sgACC and its corresponding disrupted frontal-limbic-visual cognitive-cerebellum functional networks in MDD. These findings may provide a new insight for the diagnosis and treatment of MDD. PMID:28018183

  14. Soft Power and Cultural Diplomacy: Emerging Education Hubs in Asia

    ERIC Educational Resources Information Center

    Lee, Jack T.

    2015-01-01

    Several education hubs have emerged in Asia and the Middle East in recent years with a specific focus on cross-border higher education. Through considerable efforts in policy planning and generous funding, these hubs aim to transform a country or city into an eminent destination for education, research, and training. The inherent design of these…

  15. Education Hubs: A Fad, a Brand, an Innovation?

    ERIC Educational Resources Information Center

    Knight, Jane

    2011-01-01

    The last decade has seen significant changes in all aspects of internationalization but most dramatically in the area of education and research moving across national borders. The most recent developments are education hubs. The term "education hub" is being used by countries who are trying to build a critical mass of local and foreign…

  16. International Education Hubs: Collaboration for Competitiveness and Sustainability

    ERIC Educational Resources Information Center

    Knight, Jane

    2014-01-01

    This chapter focuses on the development of education hubs, a recent phenomenon in international higher education. Three models of hubs are examined in relation to the forces, risks, and opportunities of globalization and how local and international collaborations are essential for both global competitiveness and sustainability.

  17. International Education Hubs: Collaboration for Competitiveness and Sustainability

    ERIC Educational Resources Information Center

    Knight, Jane

    2014-01-01

    This chapter focuses on the development of education hubs, a recent phenomenon in international higher education. Three models of hubs are examined in relation to the forces, risks, and opportunities of globalization and how local and international collaborations are essential for both global competitiveness and sustainability.

  18. Education Hubs: A Fad, a Brand, an Innovation?

    ERIC Educational Resources Information Center

    Knight, Jane

    2011-01-01

    The last decade has seen significant changes in all aspects of internationalization but most dramatically in the area of education and research moving across national borders. The most recent developments are education hubs. The term "education hub" is being used by countries who are trying to build a critical mass of local and foreign…

  19. Soft Power and Cultural Diplomacy: Emerging Education Hubs in Asia

    ERIC Educational Resources Information Center

    Lee, Jack T.

    2015-01-01

    Several education hubs have emerged in Asia and the Middle East in recent years with a specific focus on cross-border higher education. Through considerable efforts in policy planning and generous funding, these hubs aim to transform a country or city into an eminent destination for education, research, and training. The inherent design of these…

  20. 78 FR 21930 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Filing Take notice that on March 29, 2013, Moss Bluff Hub, LLC filed to revise its Statement of Operating Conditions to modify Sections 3.4.4,...

  1. 76 FR 10581 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-25

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Filing Take notice that on February 11, 2011, Moss Bluff Hub, LLC filed to revise its Statement of General Terms and Standard Operating Conditions...

  2. 78 FR 41397 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ... Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Filing Take notice that on June 28, 2013, Moss Bluff Hub, LLC (Moss Bluff) filed a revised Statement of Operating Conditions (SOC) pursuant to sections 284.123 and 284.224 of the Commission's regulations, (18 CFR 284.123 and 284.224). Moss...

  3. 77 FR 70431 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Filing Take notice that on November 15, 2012, Moss Bluff Hub, LLC, (Moss Bluff) filed to revise its Statement of Operating Conditions (SOC)...

  4. Climate programs update: USDA Southwest Regional Climate Hub update

    USDA-ARS?s Scientific Manuscript database

    PROGRAM OVERVIEW: The overarching goal of the USDA SW Climate Hub is to assist farmers, ranchers and foresters in addressing the effects of climate change including prolonged drought, increased insect outbreaks and severe wildfires. In the first year of operations, the SW Climate Hub (est. Februa...

  5. Evidence for hubs in human functional brain networks

    PubMed Central

    Power, Jonathan D; Schlaggar, Bradley L; Lessov-Schlaggar, Christina N; Petersen, Steven E

    2013-01-01

    Summary Hubs integrate and distribute information in powerful ways due to the number and positioning of their contacts in a network. Several resting state functional connectivity MRI reports have implicated regions of the default mode system as brain hubs; we demonstrate that previous degree-based approaches to hub identification may have identified portions of large brain systems rather than critical nodes of brain networks. We utilize two methods to identify hub-like brain regions: 1) finding network nodes that participate in multiple sub-networks of the brain, and 2) finding spatial locations where several systems are represented within a small volume. These methods converge on a distributed set of regions that differ from previous reports on hubs. This work identifies regions that support multiple systems, leading to spatially constrained predictions about brain function that may be tested in terms of lesions, evoked responses, and dynamic patterns of activity. PMID:23972601

  6. Numerical investigation of hub clearance flow in a Kaplan turbine

    NASA Astrophysics Data System (ADS)

    Wu, H.; Feng, J. J.; Wu, G. K.; Luo, X. Q.

    2012-11-01

    In this paper, the flow field considering the hub clearance flow in a Kaplan turbine has been investigated through using the commercial CFD code ANSYS CFX based on high-quality structured grids generated by ANSYS ICEM CFD. The turbulence is simulated by k-ω based shear stress transport (SST) turbulence model together with automatic near wall treatments. Four kinds of simulations have been conducted for the runner geometry without hub clearance, with only the hub front clearance, with only the rear hub clearance, and with both front and rear clearance. The analysis of the obtained results is focused on the flow structure of the hub clearance flow, the effect on the turbine performance including hydraulic efficiency and cavitation performance, which can improve the understanding on the flow field in a Kaplan turbine.

  7. In vivo two-photon excited fluorescence microscopy reveals cardiac- and respiration-dependent pulsatile blood flow in cortical blood vessels in mice.

    PubMed

    Santisakultarm, Thom P; Cornelius, Nathan R; Nishimura, Nozomi; Schafer, Andrew I; Silver, Richard T; Doerschuk, Peter C; Olbricht, William L; Schaffer, Chris B

    2012-04-01

    Subtle alterations in cerebral blood flow can impact the health and function of brain cells and are linked to cognitive decline and dementia. To understand hemodynamics in the three-dimensional vascular network of the cerebral cortex, we applied two-photon excited fluorescence microscopy to measure the motion of red blood cells (RBCs) in individual microvessels throughout the vascular hierarchy in anesthetized mice. To resolve heartbeat- and respiration-dependent flow dynamics, we simultaneously recorded the electrocardiogram and respiratory waveform. We found that centerline RBC speed decreased with decreasing vessel diameter in arterioles, slowed further through the capillary bed, and then increased with increasing vessel diameter in venules. RBC flow was pulsatile in nearly all cortical vessels, including capillaries and venules. Heartbeat-induced speed modulation decreased through the vascular network, while the delay between heartbeat and the time of maximum speed increased. Capillary tube hematocrit was 0.21 and did not vary with centerline RBC speed or topological position. Spatial RBC flow profiles in surface vessels were blunted compared with a parabola and could be measured at vascular junctions. Finally, we observed a transient decrease in RBC speed in surface vessels before inspiration. In conclusion, we developed an approach to study detailed characteristics of RBC flow in the three-dimensional cortical vasculature, including quantification of fluctuations in centerline RBC speed due to cardiac and respiratory rhythms and flow profile measurements. These methods and the quantitative data on basal cerebral hemodynamics open the door to studies of the normal and diseased-state cerebral microcirculation.

  8. EEG frequency tagging using ultra-slow periodic heat stimulation of the skin reveals cortical activity specifically related to C fiber thermonociceptors

    PubMed Central

    Colon, Elisabeth; Liberati, Giulia; Mouraux, André

    2017-01-01

    The recording of event-related brain potentials triggered by a transient heat stimulus is used extensively to study nociception and diagnose lesions or dysfunctions of the nociceptive system in humans. However, these responses are related exclusively to the activation of a specific subclass of nociceptive afferents: quickly-adapting thermonociceptors. In fact, except if the activation of Aδ fibers is avoided or if A fibers are blocked, these responses specifically reflect activity triggered by the activation of Type 2 quickly-adapting A fiber mechano-heat nociceptors (AMH-2). Here, we propose a novel method to isolate, in the human electroencephalogram (EEG), cortical activity related to the sustained periodic activation of heat-sensitive thermonociceptors, using very slow (0.2 Hz) and long-lasting (75 s) sinusoidal heat stimulation of the skin between baseline and 50°C. In a first experiment, we show that when such long-lasting thermal stimuli are applied to the hand dorsum of healthy volunteers, the slow rises and decreases of skin temperature elicit a consistent periodic EEG response at 0.2 Hz and its harmonics, as well as a periodic modulation of the magnitude of theta, alpha and beta band EEG oscillations. In a second experiment, we demonstrate using an A fiber block that these EEG responses are predominantly conveyed by unmyelinated C fiber nociceptors. The proposed approach constitutes a novel mean to study C fiber function in humans, and to explore the cortical processing of tonic heat pain in physiological and pathological conditions. PMID:27871921

  9. Sex Differences in Gamma Band Functional Connectivity Between the Frontal Lobe and Cortical Areas During an Auditory Oddball Task, as Revealed by Imaginary Coherence Assessment

    PubMed Central

    Fujimoto, Toshiro; Okumura, Eiichi; Kodabashi, Atsushi; Takeuchi, Kouzou; Otsubo, Toshiaki; Nakamura, Katsumi; Yatsushiro, Kazutaka; Sekine, Masaki; Kamiya, Shinichiro; Shimooki, Susumu; Tamura, Toshiyo

    2016-01-01

    We studied sex-related differences in gamma oscillation during an auditory oddball task, using magnetoencephalography and electroencephalography assessment of imaginary coherence (IC). We obtained a statistical source map of event-related desynchronization (ERD) / event-related synchronization (ERS), and compared females and males regarding ERD / ERS. Based on the results, we chose respectively seed regions for IC determinations in low (30-50 Hz), mid (50-100 Hz) and high gamma (100-150 Hz) bands. In males, ERD was increased in the left posterior cingulate cortex (CGp) at 500 ms in the low gamma band, and in the right caudal anterior cingulate cortex (cACC) at 125 ms in the mid-gamma band. ERS was increased in the left rostral anterior cingulate cortex (rACC) at 375 ms in the high gamma band. We chose the CGp, cACC and rACC as seeds, and examined IC between the seed and certain target regions using the IC map. IC changes depended on the height of the gamma frequency and the time window in the gamma band. Although IC in the mid and high gamma bands did not show sex-specific differences, IC at 30-50 Hz in males was increased between the left rACC and the frontal, orbitofrontal, inferior temporal and fusiform target regions. Increased IC in males suggested that males may acomplish the task constructively, analysingly, emotionally, and by perfoming analysis, and that information processing was more complicated in the cortico-cortical circuit. On the other hand, females showed few differences in IC. Females planned the task with general attention and economical well-balanced processing, which was explained by the higher overall functional cortical connectivity. CGp, cACC and rACC were involved in sex differences in information processing and were likely related to differences in neuroanatomy, hormones and neurotransmitter systems. PMID:27708745

  10. EEG frequency tagging using ultra-slow periodic heat stimulation of the skin reveals cortical activity specifically related to C fiber thermonociceptors.

    PubMed

    Colon, Elisabeth; Liberati, Giulia; Mouraux, André

    2017-02-01

    The recording of event-related brain potentials triggered by a transient heat stimulus is used extensively to study nociception and diagnose lesions or dysfunctions of the nociceptive system in humans. However, these responses are related exclusively to the activation of a specific subclass of nociceptive afferents: quickly-adapting thermonociceptors. In fact, except if the activation of Aδ fibers is avoided or if A fibers are blocked, these responses specifically reflect activity triggered by the activation of Type 2 quickly-adapting A fiber mechano-heat nociceptors (AMH-2). Here, we propose a novel method to isolate, in the human electroencephalogram (EEG), cortical activity related to the sustained periodic activation of heat-sensitive thermonociceptors, using very slow (0.2Hz) and long-lasting (75s) sinusoidal heat stimulation of the skin between baseline and 50°C. In a first experiment, we show that when such long-lasting thermal stimuli are applied to the hand dorsum of healthy volunteers, the slow rises and decreases of skin temperature elicit a consistent periodic EEG response at 0.2Hz and its harmonics, as well as a periodic modulation of the magnitude of theta, alpha and beta band EEG oscillations. In a second experiment, we demonstrate using an A fiber block that these EEG responses are predominantly conveyed by unmyelinated C fiber nociceptors. The proposed approach constitutes a novel mean to study C fiber function in humans, and to explore the cortical processing of tonic heat pain in physiological and pathological conditions.

  11. In vivo two-photon excited fluorescence microscopy reveals cardiac- and respiration-dependent pulsatile blood flow in cortical blood vessels in mice

    PubMed Central

    Santisakultarm, Thom P.; Cornelius, Nathan R.; Nishimura, Nozomi; Schafer, Andrew I.; Silver, Richard T.; Doerschuk, Peter C.; Olbricht, William L.

    2012-01-01

    Subtle alterations in cerebral blood flow can impact the health and function of brain cells and are linked to cognitive decline and dementia. To understand hemodynamics in the three-dimensional vascular network of the cerebral cortex, we applied two-photon excited fluorescence microscopy to measure the motion of red blood cells (RBCs) in individual microvessels throughout the vascular hierarchy in anesthetized mice. To resolve heartbeat- and respiration-dependent flow dynamics, we simultaneously recorded the electrocardiogram and respiratory waveform. We found that centerline RBC speed decreased with decreasing vessel diameter in arterioles, slowed further through the capillary bed, and then increased with increasing vessel diameter in venules. RBC flow was pulsatile in nearly all cortical vessels, including capillaries and venules. Heartbeat-induced speed modulation decreased through the vascular network, while the delay between heartbeat and the time of maximum speed increased. Capillary tube hematocrit was 0.21 and did not vary with centerline RBC speed or topological position. Spatial RBC flow profiles in surface vessels were blunted compared with a parabola and could be measured at vascular junctions. Finally, we observed a transient decrease in RBC speed in surface vessels before inspiration. In conclusion, we developed an approach to study detailed characteristics of RBC flow in the three-dimensional cortical vasculature, including quantification of fluctuations in centerline RBC speed due to cardiac and respiratory rhythms and flow profile measurements. These methods and the quantitative data on basal cerebral hemodynamics open the door to studies of the normal and diseased-state cerebral microcirculation. PMID:22268102

  12. Cortical Visual Impairment

    MedlinePlus

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Cortical Visual Impairment En Español Read in Chinese What is cortical visual impairment? Cortical visual impairment (CVI) is a decreased ...

  13. Hub and pylon fairing integration for helicopter drag reduction

    NASA Technical Reports Server (NTRS)

    Martin, D. M.; Mort, R. W.; Squires, P. K.; Young, L. A.

    1991-01-01

    The results of testing hub and pylon fairings mounted on a one-fifth scale helicopter with the goal of reducing parasite drag are presented. Lift, drag, and pitching moment, as well as side force and yawing moment, were measured. The primary objective of the test was to validate the drag reduction capability of integrated hub and pylon configurations in the aerodynamic environment produced by a rotating hub in forward flight. In addition to the baseline helicopter without fairings, three hub fairings and three pylon fairings were tested in various combinations. The three hub fairings tested reflect two different conceptual design approaches to implementing an integrated fairing configuration on an actual aircraft. The design philosophy is discussed in detail and comparisons are made between the wind tunnel models and potential full-scale prototypes. The data show that model drag can be reduced by as much as 20.8 percent by combining a small hub fairing with circular arc upper and flat lower surfaces and a nontapered 34-percent thick pylon fairing. Aerodynamic effects caused by the fairings, which may have a significant impact on static longitudinal and directional stability, were observed. The results support previous research which showed that the greatest reduction in model drag is achieved if the hub and pylon fairings are integrated with minimum gap between the two.

  14. A transcriptional signature of hub connectivity in the mouse connectome

    PubMed Central

    Fulcher, Ben D.; Fornito, Alex

    2016-01-01

    Connectivity is not distributed evenly throughout the brain. Instead, it is concentrated on a small number of highly connected neural elements that act as network hubs. Across different species and measurement scales, these hubs show dense interconnectivity, forming a core or “rich club” that integrates information across anatomically distributed neural systems. Here, we show that projections between connectivity hubs of the mouse brain are both central (i.e., they play an important role in neural communication) and costly (i.e., they extend over long anatomical distances) aspects of network organization that carry a distinctive genetic signature. Analyzing the neuronal connectivity of 213 brain regions and the transcriptional coupling, across 17,642 genes, between each pair of regions, we find that coupling is highest for pairs of connected hubs, intermediate for links between hubs and nonhubs, and lowest for connected pairs of nonhubs. The high transcriptional coupling associated with hub connectivity is driven by genes regulating the oxidative synthesis and metabolism of ATP—the primary energetic currency of neuronal communication. This genetic signature contrasts that identified for neuronal connectivity in general, which is driven by genes regulating neuronal, synaptic, and axonal structure and function. Our findings establish a direct link between molecular function and the large-scale topology of neuronal connectivity, showing that brain hubs display a tight coordination of gene expression, often over long anatomical distances, that is intimately related to the metabolic requirements of these highly active network elements. PMID:26772314

  15. Hub and pylon fairing integration for helicopter drag reduction

    NASA Technical Reports Server (NTRS)

    Martin, D. M.; Mort, R. W.; Squires, P. K.; Young, L. A.

    1991-01-01

    The results of testing hub and pylon fairings mounted on a one-fifth scale helicopter with the goal of reducing parasite drag are presented. Lift, drag, and pitching moment, as well as side force and yawing moment, were measured. The primary objective of the test was to validate the drag reduction capability of integrated hub and pylon configurations in the aerodynamic environment produced by a rotating hub in forward flight. In addition to the baseline helicopter without fairings, three hub fairings and three pylon fairings were tested in various combinations. The three hub fairings tested reflect two different conceptual design approaches to implementing an integrated fairing configuration on an actual aircraft. The design philosophy is discussed in detail and comparisons are made between the wind tunnel models and potential full-scale prototypes. The data show that model drag can be reduced by as much as 20.8 percent by combining a small hub fairing with circular arc upper and flat lower surfaces and a nontapered 34-percent thick pylon fairing. Aerodynamic effects caused by the fairings, which may have a significant impact on static longitudinal and directional stability, were observed. The results support previous research which showed that the greatest reduction in model drag is achieved if the hub and pylon fairings are integrated with minimum gap between the two.

  16. A Three-Dimensional Computer Simulation Model Reveals the Mechanisms for Self-Organization of Plant Cortical Microtubules into Oblique Arrays

    PubMed Central

    Eren, Ezgi Can; Gautam, Natarajan

    2010-01-01

    The noncentrosomal cortical microtubules (CMTs) of plant cells self-organize into a parallel three-dimensional (3D) array that is oriented transverse to the cell elongation axis in wild-type plants and is oblique in some of the mutants that show twisted growth. To study the mechanisms of CMT array organization, we developed a 3D computer simulation model based on experimentally observed properties of CMTs. Our computer model accurately mimics transverse array organization and other fundamental properties of CMTs observed in rapidly elongating wild-type cells as well as the defective CMT phenotypes observed in the Arabidopsis mor1-1 and fra2 mutants. We found that CMT interactions, boundary conditions, and the bundling cutoff angle impact the rate and extent of CMT organization, whereas branch-form CMT nucleation did not significantly impact the rate of CMT organization but was necessary to generate polarity during CMT organization. We also found that the dynamic instability parameters from twisted growth mutants were not sufficient to generate oblique CMT arrays. Instead, we found that parameters regulating branch-form CMT nucleation and boundary conditions at the end walls are important for forming oblique CMT arrays. Together, our computer model provides new mechanistic insights into how plant CMTs self-organize into specific 3D arrangements. PMID:20519434

  17. The Opportunities and Threats of Turning Airports into Hubs

    NASA Technical Reports Server (NTRS)

    Kraus, Andreas; Koch, Benjamin

    2006-01-01

    This paper examines the opportunities and threats which arise when turning origin/destination airports into hubs. The analysis focuses on market development trends, competitive structures, especially in the light of airline network strategies and the growing rivalry between airports, and finally the potential financial impacts for the airport, including both investment efforts and the financial results from hub operations. We argue that in most cases a decision against converting a traditional origin/destination airport into a major transfer point is preferable to the transformation into a hub.

  18. Integrated technology rotor/flight research rotor hub concept definition

    NASA Technical Reports Server (NTRS)

    Dixon, P. G. C.

    1983-01-01

    Two variations of the helicopter bearingless main rotor hub concept are proposed as bases for further development in the preliminary design phase of the Integrated Technology Rotor/Flight Research Rotor (ITR/FRR) program. This selection was the result of an evaluation of three bearingless hub concepts and two articulated hub concepts with elastomeric bearings. The characteristics of each concept were evaluated by means of simplified methodology. These characteristics included the assessment of stability, vulnerability, weight, drag, cost, stiffness, fatigue life, maintainability, and reliability.

  19. Mu-Opioid Stimulation in Rat Prefrontal Cortex Engages Hypothalamic Orexin/Hypocretin-Containing Neurons, and Reveals Dissociable Roles of Nucleus Accumbens and Hypothalamus in Cortically Driven Feeding

    PubMed Central

    Mena, Jesus D.; Selleck, Ryan A.

    2013-01-01

    Mu-opioid receptor (μOR) stimulation within ventral medial prefrontal cortex (vmPFC) induces feeding and hyperactivity, resulting possibly from recruitment of glutamate signaling in multiple vmPFC projection targets. We tested this hypothesis by analyzing Fos expression in vmPFC terminal fields after intra-vmPFC μOR stimulation, and by examining of the impact of glutamate receptor blockade in two feeding-related targets of vmPFC, the lateral-perifornical hypothalamic area (LH-PeF) and nucleus accumbens shell (Acb shell), upon behavioral effects elicited by intra-vmPFC μOR stimulation in rats. Intra-vmPFC infusion of the μOR agonist, DAMGO, provoked Fos expression in the dorsomedial sector of tuberal hypothalamus (including the perifornical area) and increased the percentage of Fos-expressing hypocretin/orexin-immunoreactive neurons in these zones. NMDA receptor blockade in the LH-PeF nearly eliminated intra-vmPFC DAMGO-induced food intake without altering DAMGO-induced hyperactivity. In contrast, blocking AMPA-type glutamate receptors within the Acb shell (the feeding-relevant subtype in this structure) antagonized intra-vmPFC DAMGO-induced hyperlocomotion but enhanced food intake. Intra-vmPFC DAMGO also elevated the breakpoint for sucrose-reinforced progressive-ratio responding; this effect was significantly enhanced by concomitant AMPA blockade in the Acb shell. Conversely, intra-Acb shell AMPA stimulation reduced breakpoint and increased nonspecific responding on the inactive lever. These data indicate intra-vmPFC μOR signaling jointly modulates appetitive motivation and generalized motoric activation through functionally dissociable vmPFC projection targets. These findings may shed light on the circuitry underlying disorganized appetitive responses in psychopathology; e.g., binge eating and opiate or alcohol abuse, disorders in which μORs and aberrant cortical activation have been implicated. PMID:24259576

  20. ECoG high gamma activity reveals distinct cortical representations of lyrics passages, harmonic and timbre-related changes in a rock song

    PubMed Central

    Sturm, Irene; Blankertz, Benjamin; Potes, Cristhian; Schalk, Gerwin; Curio, Gabriel

    2014-01-01

    Listening to music moves our minds and moods, stirring interest in its neural underpinnings. A multitude of compositional features drives the appeal of natural music. How such original music, where a composer's opus is not manipulated for experimental purposes, engages a listener's brain has not been studied until recently. Here, we report an in-depth analysis of two electrocorticographic (ECoG) data sets obtained over the left hemisphere in ten patients during presentation of either a rock song or a read-out narrative. First, the time courses of five acoustic features (intensity, presence/absence of vocals with lyrics, spectral centroid, harmonic change, and pulse clarity) were extracted from the audio tracks and found to be correlated with each other to varying degrees. In a second step, we uncovered the specific impact of each musical feature on ECoG high-gamma power (70–170 Hz) by calculating partial correlations to remove the influence of the other four features. In the music condition, the onset and offset of vocal lyrics in ongoing instrumental music was consistently identified within the group as the dominant driver for ECoG high-gamma power changes over temporal auditory areas, while concurrently subject-individual activation spots were identified for sound intensity, timbral, and harmonic features. The distinct cortical activations to vocal speech-related content embedded in instrumental music directly demonstrate that song integrated in instrumental music represents a distinct dimension in complex music. In contrast, in the speech condition, the full sound envelope was reflected in the high gamma response rather than the onset or offset of the vocal lyrics. This demonstrates how the contributions of stimulus features that modulate the brain response differ across the two examples of a full-length natural stimulus, which suggests a context-dependent feature selection in the processing of complex auditory stimuli. PMID:25352799

  1. ECoG high gamma activity reveals distinct cortical representations of lyrics passages, harmonic and timbre-related changes in a rock song.

    PubMed

    Sturm, Irene; Blankertz, Benjamin; Potes, Cristhian; Schalk, Gerwin; Curio, Gabriel

    2014-01-01

    Listening to music moves our minds and moods, stirring interest in its neural underpinnings. A multitude of compositional features drives the appeal of natural music. How such original music, where a composer's opus is not manipulated for experimental purposes, engages a listener's brain has not been studied until recently. Here, we report an in-depth analysis of two electrocorticographic (ECoG) data sets obtained over the left hemisphere in ten patients during presentation of either a rock song or a read-out narrative. First, the time courses of five acoustic features (intensity, presence/absence of vocals with lyrics, spectral centroid, harmonic change, and pulse clarity) were extracted from the audio tracks and found to be correlated with each other to varying degrees. In a second step, we uncovered the specific impact of each musical feature on ECoG high-gamma power (70-170 Hz) by calculating partial correlations to remove the influence of the other four features. In the music condition, the onset and offset of vocal lyrics in ongoing instrumental music was consistently identified within the group as the dominant driver for ECoG high-gamma power changes over temporal auditory areas, while concurrently subject-individual activation spots were identified for sound intensity, timbral, and harmonic features. The distinct cortical activations to vocal speech-related content embedded in instrumental music directly demonstrate that song integrated in instrumental music represents a distinct dimension in complex music. In contrast, in the speech condition, the full sound envelope was reflected in the high gamma response rather than the onset or offset of the vocal lyrics. This demonstrates how the contributions of stimulus features that modulate the brain response differ across the two examples of a full-length natural stimulus, which suggests a context-dependent feature selection in the processing of complex auditory stimuli.

  2. How 'love' and 'hate' differ from 'sleep': using combined electro/magnetoencephalographic data to reveal the sources of early cortical responses to emotional words.

    PubMed

    Keuper, Kati; Zwanzger, Peter; Nordt, Marisa; Eden, Annuschka; Laeger, Inga; Zwitserlood, Pienie; Kissler, Johanna; Junghöfer, Markus; Dobel, Christian

    2014-03-01

    Emotional words--as symbols for biologically relevant concepts--are preferentially processed in brain regions including the visual cortex, frontal and parietal regions, and a corticolimbic circuit including the amygdala. Some of the brain structures found in functional magnetic resonance imaging are not readily apparent in electro- and magnetoencephalographic (EEG; MEG) measures. By means of a combined EEG/MEG source localization procedure to fully exploit the available information, we sought to reduce these discrepancies and gain a better understanding of spatiotemporal brain dynamics underlying emotional-word processing. Eighteen participants read high-arousing positive and negative, and low-arousing neutral nouns, while EEG and MEG were recorded simultaneously. Combined current-density reconstructions (L2-minimum norm least squares) for two early emotion-sensitive time intervals, the P1 (80-120 ms) and the early posterior negativity (EPN, 200-300 ms), were computed using realistic individual head models with a cortical constraint. The P1 time window uncovered an emotion effect peaking in the left middle temporal gyrus. In the EPN time window, processing of emotional words was associated with enhanced activity encompassing parietal and occipital areas, and posterior limbic structures. We suggest that lexical access, being underway within 100 ms, is speeded and/or favored for emotional words, possibly on the basis of an "emotional tagging" of the word form during acquisition. This gives rise to their differential processing in the EPN time window. The EPN, as an index of natural selective attention, appears to reflect an elaborate interplay of distributed structures, related to cognitive functions, such as memory, attention, and evaluation of emotional stimuli. Copyright © 2012 Wiley Periodicals, Inc.

  3. Active Hematopoietic Hubs in Drosophila Adults Generate Hemocytes and Contribute to Immune Response

    PubMed Central

    Ghosh, Saikat; Singh, Arashdeep; Mandal, Sudip; Mandal, Lolitika

    2015-01-01

    Summary Blood cell development in Drosophila shares significant similarities with vertebrate. The conservation ranges from biphasic mode of hematopoiesis to signaling molecules crucial for progenitor cell formation, maintenance, and differentiation. Primitive hematopoiesis in Drosophila ensues in embryonic head mesoderm, whereas definitive hematopoiesis happens in larval hematopoietic organ, the lymph gland. This organ, with the onset of pupation, ruptures to release hemocytes into circulation. It is believed that the adult lacks a hematopoietic organ and survives on the contribution of both embryonic and larval hematopoiesis. However, our studies revealed a surge of blood cell development in the dorsal abdominal hemocyte clusters of adult fly. These active hematopoietic hubs are capable of blood cell specification and can respond to bacterial challenges. The presence of progenitors and differentiated hemocytes embedded in a functional network of Laminin A and Pericardin within this hematopoietic hub projects it as a simple version of the vertebrate bone marrow. PMID:25959225

  4. The central amygdala as an integrative hub for anxiety and alcohol use disorders.

    PubMed

    Gilpin, Nicholas W; Herman, Melissa A; Roberto, Marisa

    2015-05-15

    The central amygdala (CeA) plays a central role in physiologic and behavioral responses to fearful stimuli, stressful stimuli, and drug-related stimuli. The CeA receives dense inputs from cortical regions, is the major output region of the amygdala, is primarily GABAergic (inhibitory), and expresses high levels of prostress and antistress peptides. The CeA is also a constituent region of a conceptual macrostructure called the extended amygdala that is recruited during the transition to alcohol dependence. We discuss neurotransmission in the CeA as a potential integrative hub between anxiety disorders and alcohol use disorder, which are commonly co-occurring in humans. Imaging studies in humans and multidisciplinary work in animals collectively suggest that CeA structure and function are altered in individuals with anxiety disorders and alcohol use disorder, the end result of which may be disinhibition of downstream "effector" regions that regulate anxiety-related and alcohol-related behaviors.

  5. 5. DETAIL VIEW LOOKING AT FLYWHEEL HUB OF BLOWING ENGINE. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL VIEW LOOKING AT FLYWHEEL HUB OF BLOWING ENGINE. (THE MAN IS MR. FIELD CURRY). - U.S. Steel Corporation, Clairton Works, Blast Furnace Blowing Engine Building, 400 State Street, Clairton, Allegheny County, PA

  6. Optimization of Baseplate Hub Design for Swaging Operation

    NASA Astrophysics Data System (ADS)

    Ee, K. C.; Hahn, Peter; Holaway, Brett

    Swaging process is studied through a 2-D axisymmetric finite element model with non-linear material models and allowing large deformation. The effects of major baseplate hub geometrical parameters are studied for the case of a single actuator arm with two suspensions. Linear regression model is established to quantify the important output variables. The linear regression model provides a clear understanding of the effects of hub dimensions.

  7. Perspectives on the Development of LNG Market Hubs in the Asia Pacific Region

    EIA Publications

    2017-01-01

    The report discusses current initiatives to establish regional liquefied natural gas (LNG) trading hubs and pricing benchmarks in Asia and assesses the prospects for the Asian gas hubs in the near future. The report examines the characteristics of successful natural gas trading hubs and develops qualitative and quantitative indicators of the components of effective hubs, with emphasis on applying these indicators to Asian markets

  8. USDA southwest regional hub for adaptation to and mitigation of climate change

    USDA-ARS?s Scientific Manuscript database

    The USDA Southwest (SW) Climate Hub was created in February 2014 to develop risk adaptation and mitigation strategies for coping with climate change effects on agricultural productivity. There are seven regional hubs across the country with three subsidiary hubs. The SW Climate Hub Region is made ...

  9. Hierarchical Feedback Modules and Reaction Hubs in Cell Signaling Networks

    PubMed Central

    Xu, Jianfeng; Lan, Yueheng

    2015-01-01

    Despite much effort, identification of modular structures and study of their organizing and functional roles remain a formidable challenge in molecular systems biology, which, however, is essential in reaching a systematic understanding of large-scale cell regulation networks and hence gaining capacity of exerting effective interference to cell activity. Combining graph theoretic methods with available dynamics information, we successfully retrieved multiple feedback modules of three important signaling networks. These feedbacks are structurally arranged in a hierarchical way and dynamically produce layered temporal profiles of output signals. We found that global and local feedbacks act in very different ways and on distinct features of the information flow conveyed by signal transduction but work highly coordinately to implement specific biological functions. The redundancy embodied with multiple signal-relaying channels and feedback controls bestow great robustness and the reaction hubs seated at junctions of different paths announce their paramount importance through exquisite parameter management. The current investigation reveals intriguing general features of the organization of cell signaling networks and their relevance to biological function, which may find interesting applications in analysis, design and control of bio-networks. PMID:25951347

  10. Network modules and hubs in plant-root fungal biomes

    PubMed Central

    Toju, Hirokazu; Yamamoto, Satoshi; Tanabe, Akifumi S.; Hayakawa, Takashi; Ishii, Hiroshi S.

    2016-01-01

    Terrestrial plants host phylogenetically and functionally diverse groups of below-ground microbes, whose community structure controls plant growth/survival in both natural and agricultural ecosystems. Therefore, understanding the processes by which whole root-associated microbiomes are organized is one of the major challenges in ecology and plant science. We here report that diverse root-associated fungi can form highly compartmentalized networks of coexistence within host roots and that the structure of the fungal symbiont communities can be partitioned into semi-discrete types even within a single host plant population. Illumina sequencing of root-associated fungi in a monodominant south beech forest revealed that the network representing symbiont–symbiont co-occurrence patterns was compartmentalized into clear modules, which consisted of diverse functional groups of mycorrhizal and endophytic fungi. Consequently, terminal roots of the plant were colonized by either of the two largest fungal species sets (represented by Oidiodendron or Cenococcum). Thus, species-rich root microbiomes can have alternative community structures, as recently shown in the relationships between human gut microbiome type (i.e. ‘enterotype’) and host individual health. This study also shows an analytical framework for pinpointing network hubs in symbiont–symbiont networks, leading to the working hypothesis that a small number of microbial species organize the overall root–microbiome dynamics. PMID:26962029

  11. Cortical dynamics and subcortical signatures of motor-language coupling in Parkinson’s disease

    PubMed Central

    Melloni, Margherita; Sedeño, Lucas; Hesse, Eugenia; García-Cordero, Indira; Mikulan, Ezequiel; Plastino, Angelo; Marcotti, Aida; López, José David; Bustamante, Catalina; Lopera, Francisco; Pineda, David; García, Adolfo M.; Manes, Facundo; Trujillo, Natalia; Ibáñez, Agustín

    2015-01-01

    Impairments of action language have been documented in early stage Parkinson’s disease (EPD). The action-sentence compatibility effect (ACE) paradigm has revealed that EPD involves deficits to integrate action-verb processing and ongoing motor actions. Recent studies suggest that an abolished ACE in EPD reflects a cortico-subcortical disruption, and recent neurocognitive models highlight the role of the basal ganglia (BG) in motor-language coupling. Building on such breakthroughs, we report the first exploration of convergent cortical and subcortical signatures of ACE in EPD patients and matched controls. Specifically, we combined cortical recordings of the motor potential, functional connectivity measures, and structural analysis of the BG through voxel-based morphometry. Relative to controls, EPD patients exhibited an impaired ACE, a reduced motor potential, and aberrant frontotemporal connectivity. Furthermore, motor potential abnormalities during the ACE task were predicted by overall BG volume and atrophy. These results corroborate that motor-language coupling is mainly subserved by a cortico-subcortical network including the BG as a key hub. They also evince that action-verb processing may constitute a neurocognitive marker of EPD. Our findings suggest that research on the relationship between language and motor domains is crucial to develop models of motor cognition as well as diagnostic and intervention strategies. PMID:26152329

  12. Circadian regulation of human cortical excitability

    PubMed Central

    Ly, Julien Q. M.; Gaggioni, Giulia; Chellappa, Sarah L.; Papachilleos, Soterios; Brzozowski, Alexandre; Borsu, Chloé; Rosanova, Mario; Sarasso, Simone; Middleton, Benita; Luxen, André; Archer, Simon N.; Phillips, Christophe; Dijk, Derk-Jan; Maquet, Pierre; Massimini, Marcello; Vandewalle, Gilles

    2016-01-01

    Prolonged wakefulness alters cortical excitability, which is essential for proper brain function and cognition. However, besides prior wakefulness, brain function and cognition are also affected by circadian rhythmicity. Whether the regulation of cognition involves a circadian impact on cortical excitability is unknown. Here, we assessed cortical excitability from scalp electroencephalography (EEG) responses to transcranial magnetic stimulation in 22 participants during 29 h of wakefulness under constant conditions. Data reveal robust circadian dynamics of cortical excitability that are strongest in those individuals with highest endocrine markers of circadian amplitude. In addition, the time course of cortical excitability correlates with changes in EEG synchronization and cognitive performance. These results demonstrate that the crucial factor for cortical excitability, and basic brain function in general, is the balance between circadian rhythmicity and sleep need, rather than sleep homoeostasis alone. These findings have implications for clinical applications such as non-invasive brain stimulation in neurorehabilitation. PMID:27339884

  13. Cortical microtubule rearrangements and cell wall patterning

    PubMed Central

    Oda, Yoshihisa

    2015-01-01

    Plant cortical microtubules, which form a highly ordered array beneath the plasma membrane, play essential roles in determining cell shape and function by directing the arrangement of cellulosic and non-cellulosic compounds on the cell surface. Interphase transverse arrays of cortical microtubules self-organize through their dynamic instability and inter-microtubule interactions, and by branch-form microtubule nucleation and severing. Recent studies revealed that distinct spatial signals including ROP GTPase, cellular geometry, and mechanical stress regulate the behavior of cortical microtubules at the subcellular and supercellular levels, giving rise to dramatic rearrangements in the cortical microtubule array in response to internal and external cues. Increasing evidence indicates that negative regulators of microtubules also contribute to the rearrangement of the cortical microtubule array. In this review, I summarize recent insights into how the rearrangement of the cortical microtubule array leads to proper, flexible cell wall patterning. PMID:25904930

  14. Positive and negative affective processing exhibit dissociable functional hubs during the viewing of affective pictures.

    PubMed

    Zhang, Wenhai; Li, Hong; Pan, Xiaohong

    2015-02-01

    Recent resting-state functional magnetic resonance imaging (fMRI) studies using graph theory metrics have revealed that the functional network of the human brain possesses small-world characteristics and comprises several functional hub regions. However, it is unclear how the affective functional network is organized in the brain during the processing of affective information. In this study, the fMRI data were collected from 25 healthy college students as they viewed a total of 81 positive, neutral, and negative pictures. The results indicated that affective functional networks exhibit weaker small-worldness properties with higher local efficiency, implying that local connections increase during viewing affective pictures. Moreover, positive and negative emotional processing exhibit dissociable functional hubs, emerging mainly in task-positive regions. These functional hubs, which are the centers of information processing, have nodal betweenness centrality values that are at least 1.5 times larger than the average betweenness centrality of the network. Positive affect scores correlated with the betweenness values of the right orbital frontal cortex (OFC) and the right putamen in the positive emotional network; negative affect scores correlated with the betweenness values of the left OFC and the left amygdala in the negative emotional network. The local efficiencies in the left superior and inferior parietal lobe correlated with subsequent arousal ratings of positive and negative pictures, respectively. These observations provide important evidence for the organizational principles of the human brain functional connectome during the processing of affective information. © 2014 Wiley Periodicals, Inc.

  15. A Dynamic Calibration Method for Experimental and Analytical Hub Load Comparison

    NASA Technical Reports Server (NTRS)

    Kreshock, Andrew R.; Thornburgh, Robert P.; Wilbur, Matthew L.

    2017-01-01

    This paper presents the results from an ongoing effort to produce improved correlation between analytical hub force and moment prediction and those measured during wind-tunnel testing on the Aeroelastic Rotor Experimental System (ARES), a conventional rotor testbed commonly used at the Langley Transonic Dynamics Tunnel (TDT). A frequency-dependent transformation between loads at the rotor hub and outputs of the testbed balance is produced from frequency response functions measured during vibration testing of the system. The resulting transformation is used as a dynamic calibration of the balance to transform hub loads predicted by comprehensive analysis into predicted balance outputs. In addition to detailing the transformation process, this paper also presents a set of wind-tunnel test cases, with comparisons between the measured balance outputs and transformed predictions from the comprehensive analysis code CAMRAD II. The modal response of the testbed is discussed and compared to a detailed finite-element model. Results reveal that the modal response of the testbed exhibits a number of characteristics that make accurate dynamic balance predictions challenging, even with the use of the balance transformation.

  16. Abnormal intrinsic functional hubs in alcohol dependence: evidence from a voxelwise degree centrality analysis.

    PubMed

    Luo, Xiaoping; Guo, Linghong; Dai, Xi-Jian; Wang, Qinglai; Zhu, Wenzhong; Miao, Xinjun; Gong, Honghan

    2017-01-01

    To explore the abnormal intrinsic functional hubs in alcohol dependence using voxelwise degree centrality analysis approach, and their relationships with clinical features. Twenty-four male alcohol dependence subjects free of medicine (mean age, 50.21±9.62 years) and 24 age- and education-matched male healthy controls (mean age, 50.29±8.92 years) were recruited. The alcohol use disorders identification test and the severity of alcohol dependence questionnaire (SADQ) were administered to assess the severity of alcohol craving. Voxelwise degree centrality approach was used to assess the abnormal intrinsic functional hubs features in alcohol dependence. Simple linear regression analysis was performed to investigate the relationships between the clinical features and abnormal intrinsic functional hubs. Compared with healthy controls, alcohol dependence subjects exhibited significantly different degree centrality values in widespread left lateralization brain areas, including higher degree centrality values in the left precentral gyrus (BA 6), right hippocampus (BA 35, 36), and left orbitofrontal cortex (BA 11) and lower degree centrality values in the left cerebellum posterior lobe, bilateral secondary visual network (BA 18), and left precuneus (BA 7, 19). SADQ revealed a negative linear correlation with the degree centrality value in the left precentral gyrus (R(2)=0.296, P=0.006). The specific abnormal intrinsic functional hubs appear to be disrupted by alcohol intoxication, which implicates at least three principal neural systems: including cerebellar, executive control, and visual cortex, which may further affect the normal motor behavior such as an explicit type of impaired driving behavior. These findings expand our understanding of the functional characteristics of alcohol dependence and may provide a new insight into the understanding of the dysfunction and pathophysiology of alcohol dependence.

  17. Modeling of UH-60A Hub Accelerations with Neural Networks

    NASA Technical Reports Server (NTRS)

    Kottapalli, Sesi

    2002-01-01

    Neural network relationships between the full-scale, flight test hub accelerations and the corresponding three N/rev pilot floor vibration components (vertical, lateral, and longitudinal) are studied. The present quantitative effort on the UH-60A Black Hawk hub accelerations considers the lateral and longitudinal vibrations. An earlier study had considered the vertical vibration. The NASA/Army UH-60A Airloads Program flight test database is used. A physics based "maneuver-effect-factor (MEF)", derived using the roll-angle and the pitch-rate, is used. Fundamentally, the lateral vibration data show high vibration levels (up to 0.3 g's) at low airspeeds (for example, during landing flares) and at high airspeeds (for example, during turns). The results show that the advance ratio and the gross weight together can predict the vertical and the longitudinal vibration. However, the advance ratio and the gross weight together cannot predict the lateral vibration. The hub accelerations and the advance ratio can be used to satisfactorily predict the vertical, lateral, and longitudinal vibration. The present study shows that neural network based representations of all three UH-60A pilot floor vibration components (vertical, lateral, and longitudinal) can be obtained using the hub accelerations along with the gross weight and the advance ratio. The hub accelerations are clearly a factor in determining the pilot vibration. The present conclusions potentially allow for the identification of neural network relationships between the experimental hub accelerations obtained from wind tunnel testing and the experimental pilot vibration data obtained from flight testing. A successful establishment of the above neural network based link between the wind tunnel hub accelerations and the flight test vibration data can increase the value of wind tunnel testing.

  18. Modeling of UH-60A Hub Accelerations with Neural Networks

    NASA Technical Reports Server (NTRS)

    Kottapalli, Sesi

    2002-01-01

    Neural network relationships between the full-scale, flight test hub accelerations and the corresponding three N/rev pilot floor vibration components (vertical, lateral, and longitudinal) are studied. The present quantitative effort on the UH-60A Black Hawk hub accelerations considers the lateral and longitudinal vibrations. An earlier study had considered the vertical vibration. The NASA/Army UH-60A Airloads Program flight test database is used. A physics based "maneuver-effect-factor (MEF)", derived using the roll-angle and the pitch-rate, is used. Fundamentally, the lateral vibration data show high vibration levels (up to 0.3 g's) at low airspeeds (for example, during landing flares) and at high airspeeds (for example, during turns). The results show that the advance ratio and the gross weight together can predict the vertical and the longitudinal vibration. However, the advance ratio and the gross weight together cannot predict the lateral vibration. The hub accelerations and the advance ratio can be used to satisfactorily predict the vertical, lateral, and longitudinal vibration. The present study shows that neural network based representations of all three UH-60A pilot floor vibration components (vertical, lateral, and longitudinal) can be obtained using the hub accelerations along with the gross weight and the advance ratio. The hub accelerations are clearly a factor in determining the pilot vibration. The present conclusions potentially allow for the identification of neural network relationships between the experimental hub accelerations obtained from wind tunnel testing and the experimental pilot vibration data obtained from flight testing. A successful establishment of the above neural network based link between the wind tunnel hub accelerations and the flight test vibration data can increase the value of wind tunnel testing.

  19. HIV protein sequence hotspots for crosstalk with host hub proteins.

    PubMed

    Sarmady, Mahdi; Dampier, William; Tozeren, Aydin

    2011-01-01

    HIV proteins target host hub proteins for transient binding interactions. The presence of viral proteins in the infected cell results in out-competition of host proteins in their interaction with hub proteins, drastically affecting cell physiology. Functional genomics and interactome datasets can be used to quantify the sequence hotspots on the HIV proteome mediating interactions with host hub proteins. In this study, we used the HIV and human interactome databases to identify HIV targeted host hub proteins and their host binding partners (H2). We developed a high throughput computational procedure utilizing motif discovery algorithms on sets of protein sequences, including sequences of HIV and H2 proteins. We identified as HIV sequence hotspots those linear motifs that are highly conserved on HIV sequences and at the same time have a statistically enriched presence on the sequences of H2 proteins. The HIV protein motifs discovered in this study are expressed by subsets of H2 host proteins potentially outcompeted by HIV proteins. A large subset of these motifs is involved in cleavage, nuclear localization, phosphorylation, and transcription factor binding events. Many such motifs are clustered on an HIV sequence in the form of hotspots. The sequential positions of these hotspots are consistent with the curated literature on phenotype altering residue mutations, as well as with existing binding site data. The hotspot map produced in this study is the first global portrayal of HIV motifs involved in altering the host protein network at highly connected hub nodes.

  20. Compatibility of paraldehyde with plastic syringes and needle hubs.

    PubMed

    Johnson, C E; Vigoreaux, J A

    1984-02-01

    The compatibility of paraldehyde with plastic syringes and needle hubs was evaluated. Paraldehyde, USP, was stored in three types of 5-ml syringes: Plastipak, Glaspak, and all glass; the latter type served as the control. At specified times up to 24 hours, the contents of the syringes was evaporated to constant weight, and the residue was weighed. To evaluate the effect of paraldehyde on plastic needle hubs, needles with plastic and metal hubs were immersed in paraldehyde for 24 hours, and the paraldehyde was evaporated. No measurable change in residue weight was noted in any syringes for up to three hours. Compared with the control, there was a significant increase in the average weight of residue in the Glaspak and in the Plastipak syringes at 6, 12, and 24 hours. There was no significant difference in the weight of residue between the Glaspak and Plastipak syringes at those times, however. The amount of residue for the plastic and metal needle hubs was not significantly different. The source of the extractive residue appeared to be the rubber plunger tip. Since the nature of the extractive material in the residue is not known, paraldehyde should be administered in all-glass syringes if possible; other syringe types can be used only if the drug is administered immediately. The use of needles with plastic hubs is acceptable.

  1. Preliminary analysis of hub and spoke air freight distribution system

    NASA Technical Reports Server (NTRS)

    Whitehead, A. H., Jr.

    1978-01-01

    A brief analysis is made of the hub and spoke air freight distribution system which would employ less than 15 hub centers world wide with very large advanced distributed-load freighters providing the line-haul delivery between hubs. This system is compared to a more conventional network using conventionally-designed long-haul freighters which travel between numerous major airports. The analysis calculates all of the transportation costs, including handling charges and pickup and delivery costs. The results show that the economics of the hub/spoke system are severely compromised by the extensive use of feeder aircraft to deliver cargo into and from the large freighter terminals. Not only are the higher costs for the smaller feeder airplanes disadvantageous, but their use implies an additional exchange of cargo between modes compared to truck delivery. The conventional system uses far fewer feeder airplanes, and in many cases, none at all. When feeder aircraft are eliminated from the hub/spoke system, however, that system is universally more economical than any conventional system employing smaller line-haul aircraft.

  2. fMRI Adaptation between Action Observation and Action Execution Reveals Cortical Areas with Mirror Neuron Properties in Human BA 44/45.

    PubMed

    de la Rosa, Stephan; Schillinger, Frieder L; Bülthoff, Heinrich H; Schultz, Johannes; Uludag, Kamil

    2016-01-01

    Mirror neurons (MNs) are considered to be the supporting neural mechanism for action understanding. MNs have been identified in monkey's area F5. The identification of MNs in the human homolog of monkeys' area F5 Broadmann Area 44/45 (BA 44/45) has been proven methodologically difficult. Cross-modal functional MRI (fMRI) adaptation studies supporting the existence of MNs restricted their analysis to a priori candidate regions, whereas studies that failed to find evidence used non-object-directed (NDA) actions. We tackled these limitations by using object-directed actions (ODAs) differing only in terms of their object directedness in combination with a cross-modal adaptation paradigm and a whole-brain analysis. Additionally, we tested voxels' blood oxygenation level-dependent (BOLD) response patterns for several properties previously reported as typical MN response properties. Our results revealed 52 voxels in left inferior frontal gyrus (IFG; particularly BA 44/45), which respond to both motor and visual stimulation and exhibit cross-modal adaptation between the execution and observation of the same action. These results demonstrate that part of human IFG, specifically BA 44/45, has BOLD response characteristics very similar to monkey's area F5.

  3. Source-reconstruction of event-related fields reveals hyperfunction and hypofunction of cortical circuits in antipsychotic-naive, first-episode schizophrenia patients during Mooney face processing.

    PubMed

    Rivolta, Davide; Castellanos, Nazareth P; Stawowsky, Cerisa; Helbling, Saskia; Wibral, Michael; Grützner, Christine; Koethe, Dagmar; Birkner, Katharina; Kranaster, Laura; Enning, Frank; Singer, Wolf; Leweke, F Markus; Uhlhaas, Peter J

    2014-04-23

    Schizophrenia is characterized by dysfunctions in neural circuits that can be investigated with electrophysiological methods, such as EEG and MEG. In the present human study, we examined event-related fields (ERFs), in a sample of medication-naive, first-episode schizophrenia (FE-ScZ) patients (n = 14) and healthy control participants (n = 17) during perception of Mooney faces to investigate the integrity of neuromagnetic responses and their experience-dependent modification. ERF responses were analyzed for M100, M170, and M250 components at the sensor and source levels. In addition, we analyzed peak latency and adaptation effects due to stimulus repetition. FE-ScZ patients were characterized by significantly impaired sensory processing, as indicated by a reduced discrimination index (A'). At the sensor level, M100 and M170 responses in FE-ScZ were within the normal range, whereas the M250 response was impaired. However, source localization revealed widespread elevated activity for M100 and M170 in FE-ScZ and delayed peak latencies for the M100 and M250 responses. In addition, M170 source activity in FE-ScZ was not modulated by stimulus repetitions. The present findings suggest that neural circuits in FE-ScZ may be characterized by a disturbed balance between excitation and inhibition that could lead to a failure to gate information flow and abnormal spreading of activity, which is compatible with dysfunctional glutamatergic neurotransmission.

  4. fMRI Adaptation between Action Observation and Action Execution Reveals Cortical Areas with Mirror Neuron Properties in Human BA 44/45

    PubMed Central

    de la Rosa, Stephan; Schillinger, Frieder L.; Bülthoff, Heinrich H.; Schultz, Johannes; Uludag, Kamil

    2016-01-01

    Mirror neurons (MNs) are considered to be the supporting neural mechanism for action understanding. MNs have been identified in monkey’s area F5. The identification of MNs in the human homolog of monkeys’ area F5 Broadmann Area 44/45 (BA 44/45) has been proven methodologically difficult. Cross-modal functional MRI (fMRI) adaptation studies supporting the existence of MNs restricted their analysis to a priori candidate regions, whereas studies that failed to find evidence used non-object-directed (NDA) actions. We tackled these limitations by using object-directed actions (ODAs) differing only in terms of their object directedness in combination with a cross-modal adaptation paradigm and a whole-brain analysis. Additionally, we tested voxels’ blood oxygenation level-dependent (BOLD) response patterns for several properties previously reported as typical MN response properties. Our results revealed 52 voxels in left inferior frontal gyrus (IFG; particularly BA 44/45), which respond to both motor and visual stimulation and exhibit cross-modal adaptation between the execution and observation of the same action. These results demonstrate that part of human IFG, specifically BA 44/45, has BOLD response characteristics very similar to monkey’s area F5. PMID:26973496

  5. Components of vestibular cortical function.

    PubMed

    Klingner, Carsten M; Volk, Gerd F; Flatz, Claudia; Brodoehl, Stefan; Dieterich, Marianne; Witte, Otto W; Guntinas-Lichius, Orlando

    2013-01-01

    It is known that the functional response (e.g., nystagmus) to caloric vestibular stimulation is delayed and prolonged compared with the stimulus-response timing of other sensory systems. Imaging studies have used different models to predict cortical responses and to determine the areas of the brain that are involved. These studies have revealed a widespread network of vestibular brain regions. However, there is some disagreement regarding the brain areas involved, which may partly be caused by differences in the models used. This disagreement indicates the possible existence of multiple cortical components with different temporal characteristics that underlie cortical vestibular processing. However, data-driven methods have yet to be used to analyze the underlying hemodynamic components during and after vestibular stimulation. We performed functional magnetic resonance imaging (fMRI) on 12 healthy subjects during caloric stimulation and analyzed these data using a model-free analysis method (ICA). We found seven independent stimulus-induced components that outline a robust pattern of cortical activation and deactivation. These independent components demonstrated significant differences in their time courses. No single-modeled response function was able to cover the entire range of these independent components. The response functions determined in the present study should improve model-based studies investigating vestibular cortical processing.

  6. Large-scale cortical networks and cognition.

    PubMed

    Bressler, S L

    1995-03-01

    The well-known parcellation of the mammalian cerebral cortex into a large number of functionally distinct cytoarchitectonic areas presents a problem for understanding the complex cortical integrative functions that underlie cognition. How do cortical areas having unique individual functional properties cooperate to accomplish these complex operations? Do neurons distributed throughout the cerebral cortex act together in large-scale functional assemblages? This review examines the substantial body of evidence supporting the view that complex integrative functions are carried out by large-scale networks of cortical areas. Pathway tracing studies in non-human primates have revealed widely distributed networks of interconnected cortical areas, providing an anatomical substrate for large-scale parallel processing of information in the cerebral cortex. Functional coactivation of multiple cortical areas has been demonstrated by neurophysiological studies in non-human primates and several different cognitive functions have been shown to depend on multiple distributed areas by human neuropsychological studies. Electrophysiological studies on interareal synchronization have provided evidence that active neurons in different cortical areas may become not only coactive, but also functionally interdependent. The computational advantages of synchronization between cortical areas in large-scale networks have been elucidated by studies using artificial neural network models. Recent observations of time-varying multi-areal cortical synchronization suggest that the functional topology of a large-scale cortical network is dynamically reorganized during visuomotor behavior.

  7. Localization of metastatic adrenal cortical carcinoma with Ga-67

    SciTech Connect

    Ward, F.T.; Anderson, J.H.; Jelinek, J.; Anderson, D.W. )

    1991-02-01

    Data are limited on the localization of Ga-67 in primary or metastatic adrenal cortical carcinoma. We report the localization of Ga-67 to pathologically confirmed adrenal cortical carcinoma metastatic to the lung. A review of the literature revealed four patients have previously been reported to have metastatic adrenal cortical carcinoma detected on Ga-67 scan. Gallium imaging may be useful in the evaluation of patients with adrenal cortical carcinoma. SPECT imaging should further improve lesion resolution and localization.

  8. An environmental transfer hub for multimodal atom probe tomography.

    PubMed

    Perea, Daniel E; Gerstl, Stephan S A; Chin, Jackson; Hirschi, Blake; Evans, James E

    2017-01-01

    Environmental control during transfer between instruments is required for samples sensitive to air or thermal exposure to prevent morphological or chemical changes prior to analysis. Atom probe tomography is a rapidly expanding technique for three-dimensional structural and chemical analysis, but commercial instruments remain limited to loading specimens under ambient conditions. In this study, we describe a multifunctional environmental transfer hub allowing controlled cryogenic or room-temperature transfer of specimens under atmospheric or vacuum pressure conditions between an atom probe and other instruments or reaction chambers. The utility of the environmental transfer hub is demonstrated through the acquisition of previously unavailable mass spectral analysis of an intact organic molecule made possible via controlled cryogenic transfer into the atom probe using the hub. The ability to prepare and transfer specimens in precise environments promises a means to access new science across many disciplines from untainted samples and allow downstream time-resolved in situ atom probe studies.

  9. Compact earth stations, hubs for energy industry expanding

    SciTech Connect

    Shimabukuro, T. )

    1992-02-01

    That paper reports that advances in gallium arsenide (GaAs) technology, monolithic microwave integrated circuits (MMIC) and large scale integrated (VLSF) circuits, have contributed to the mass production of very reliable small aperture terminals (VSATs). Less publicized, but equally important to multinational energy organizations, are recent developments in compact earth station design and solid-state hubs for VSAT networks made possible by the new technology. Many applications are suited for the energy industry that involve compact earth station terminals and hubs. The first group of applications describes the use of GTE's ACES earth station for the Zaire Gulf Oil Co. in Zaire and for AMOCO in Trinidad. The second group of applications describes the compact hub for VSAT networks, which could potentially have a number of data communication uses in the energy industry, such as, IBM/SNA, X.25, or supervisory control an data acquisition (SCADA) applications.

  10. Microfluidic hubs, systems, and methods for interface fluidic modules

    SciTech Connect

    Bartsch, Michael S; Claudnic, Mark R; Kim, Hanyoup; Patel, Kamlesh D; Renzi, Ronald F; Van De Vreugde, James L

    2015-01-27

    Embodiments of microfluidic hubs and systems are described that may be used to connect fluidic modules. A space between surfaces may be set by fixtures described herein. In some examples a fixture may set substrate-to-substrate spacing based on a distance between registration surfaces on which the respective substrates rest. Fluidic interfaces are described, including examples where fluid conduits (e.g. capillaries) extend into the fixture to the space between surfaces. Droplets of fluid may be introduced to and/or removed from microfluidic hubs described herein, and fluid actuators may be used to move droplets within the space between surfaces. Continuous flow modules may be integrated with the hubs in some examples.

  11. Application of hydraulically assembled shaft coupling hubs to large agitators

    SciTech Connect

    Murray, W.E.; Anderson, T.D.; Bethmann, H.K.

    1991-12-31

    This paper describes the basis for and implementation of hydraulically assembled shaft coupling hubs for large tank-mounted agitators. This modification to the original design was intended to minimize maintenance personnel exposure to ionizing radiation and also provide for disassembly capability without damage to shafts or hubs. In addition to realizing these objectives, test confirmed that the modified couplings reduced agitator shaft end runouts approximately 65%, thereby reducing bearing loads and increasing service life, a significant enhancement for a nuclear facility. 5 refs.

  12. Application of hydraulically assembled shaft coupling hubs to large agitators

    SciTech Connect

    Murray, W.E.; Anderson, T.D. ); Bethmann, H.K. )

    1991-01-01

    This paper describes the basis for and implementation of hydraulically assembled shaft coupling hubs for large tank-mounted agitators. This modification to the original design was intended to minimize maintenance personnel exposure to ionizing radiation and also provide for disassembly capability without damage to shafts or hubs. In addition to realizing these objectives, test confirmed that the modified couplings reduced agitator shaft end runouts approximately 65%, thereby reducing bearing loads and increasing service life, a significant enhancement for a nuclear facility. 5 refs.

  13. Interface structure for hub and mass attachment in flywheel rotors

    DOEpatents

    Deteresa, Steven J.; Groves, Scott E.

    1998-06-02

    An interface structure for hub and mass attachment in flywheel rotors. The interface structure efficiently transmits high radial compression forces and withstands both large circumferential elongation and local stresses generated by mass-loading and hub attachments. The interface structure is comprised of high-strength fiber, such as glass and carbon, woven into an angle pattern which is about 45.degree. with respect to the rotor axis. The woven fiber is bonded by a ductile matrix material which is compatible with and adheres to the rotor material. This woven fiber is able to elongate in the circumferential direction to match the rotor growth during spinning.

  14. Interface structure for hub and mass attachment in flywheel rotors

    DOEpatents

    Deteresa, S.J.; Groves, S.E.

    1998-06-02

    An interface structure is described for hub and mass attachment in flywheel rotors. The interface structure efficiently transmits high radial compression forces and withstands both large circumferential elongation and local stresses generated by mass-loading and hub attachments. The interface structure is comprised of high-strength fiber, such as glass and carbon, woven into an angle pattern which is about 45{degree} with respect to the rotor axis. The woven fiber is bonded by a ductile matrix material which is compatible with and adheres to the rotor material. This woven fiber is able to elongate in the circumferential direction to match the rotor growth during spinning. 2 figs.

  15. Variable volume combustor with center hub fuel staging

    DOEpatents

    Ostebee, Heath Michael; McConnaughhay, Johnie Franklin; Stewart, Jason Thurman; Keener, Christopher Paul

    2016-08-23

    The present application and the resultant patent provide a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a center hub for providing the flow of fuel therethrough. The center hub may include a first supply circuit for a first micro-mixer fuel nozzle and a second supply circuit for a second micro-mixer fuel nozzle.

  16. Analysis and Modeling of Ground Operations at Hub Airports

    NASA Technical Reports Server (NTRS)

    Atkins, Stephen (Technical Monitor); Andersson, Kari; Carr, Francis; Feron, Eric; Hall, William D.

    2000-01-01

    Building simple and accurate models of hub airports can considerably help one understand airport dynamics, and may provide quantitative estimates of operational airport improvements. In this paper, three models are proposed to capture the dynamics of busy hub airport operations. Two simple queuing models are introduced to capture the taxi-out and taxi-in processes. An integer programming model aimed at representing airline decision-making attempts to capture the dynamics of the aircraft turnaround process. These models can be applied for predictive purposes. They may also be used to evaluate control strategies for improving overall airport efficiency.

  17. Conceptual grounding of language in action and perception: a neurocomputational model of the emergence of category specificity and semantic hubs.

    PubMed

    Garagnani, Max; Pulvermüller, Friedemann

    2016-03-01

    Current neurobiological accounts of language and cognition offer diverging views on the questions of 'where' and 'how' semantic information is stored and processed in the human brain. Neuroimaging data showing consistent activation of different multi-modal areas during word and sentence comprehension suggest that all meanings are processed indistinctively, by a set of general semantic centres or 'hubs'. However, words belonging to specific semantic categories selectively activate modality-preferential areas; for example, action-related words spark activity in dorsal motor cortex, whereas object-related ones activate ventral visual areas. The evidence for category-specific and category-general semantic areas begs for a unifying explanation, able to integrate the emergence of both. Here, a neurobiological model offering such an explanation is described. Using a neural architecture replicating anatomical and neurophysiological features of frontal, occipital and temporal cortices, basic aspects of word learning and semantic grounding in action and perception were simulated. As the network underwent training, distributed lexico-semantic circuits spontaneously emerged. These circuits exhibited different cortical distributions that reached into dorsal-motor or ventral-visual areas, reflecting the correlated category-specific sensorimotor patterns that co-occurred during action- or object-related semantic grounding, respectively. Crucially, substantial numbers of neurons of both types of distributed circuits emerged in areas interfacing between modality-preferential regions, i.e. in multimodal connection hubs, which therefore became loci of general semantic binding. By relating neuroanatomical structure and cellular-level learning mechanisms with system-level cognitive function, this model offers a neurobiological account of category-general and category-specific semantic areas based on the different cortical distributions of the underlying semantic circuits.

  18. The human cerebral cortex is neither one nor many: neuronal distribution reveals two quantitatively different zones in the gray matter, three in the white matter, and explains local variations in cortical folding

    PubMed Central

    Ribeiro, Pedro F. M.; Ventura-Antunes, Lissa; Gabi, Mariana; Mota, Bruno; Grinberg, Lea T.; Farfel, José M.; Ferretti-Rebustini, Renata E. L.; Leite, Renata E. P.; Filho, Wilson J.; Herculano-Houzel, Suzana

    2013-01-01

    The human prefrontal cortex has been considered different in several aspects and relatively enlarged compared to the rest of the cortical areas. Here we determine whether the white and gray matter of the prefrontal portion of the human cerebral cortex have similar or different cellular compositions relative to the rest of the cortical regions by applying the Isotropic Fractionator to analyze the distribution of neurons along the entire anteroposterior axis of the cortex, and its relationship with the degree of gyrification, number of neurons under the cortical surface, and other parameters. The prefrontal region shares with the remainder of the cerebral cortex (except for occipital cortex) the same relationship between cortical volume and number of neurons. In contrast, both occipital and prefrontal areas vary from other cortical areas in their connectivity through the white matter, with a systematic reduction of cortical connectivity through the white matter and an increase of the mean axon caliber along the anteroposterior axis. These two parameters explain local differences in the distribution of neurons underneath the cortical surface. We also show that local variations in cortical folding are neither a function of local numbers of neurons nor of cortical thickness, but correlate with properties of the white matter, and are best explained by the folding of the white matter surface. Our results suggest that the human cerebral cortex is divided in two zones (occipital and non-occipital) that differ in how neurons are distributed across their gray matter volume and in three zones (prefrontal, occipital, and non-occipital) that differ in how neurons are connected through the white matter. Thus, the human prefrontal cortex has the largest fraction of neuronal connectivity through the white matter and the smallest average axonal caliber in the white matter within the cortex, although its neuronal composition fits the pattern found for other, non-occipital areas. PMID

  19. White Matter Disruptions in Schizophrenia Are Spatially Widespread and Topologically Converge on Brain Network Hubs.

    PubMed

    Klauser, Paul; Baker, Simon T; Cropley, Vanessa L; Bousman, Chad; Fornito, Alex; Cocchi, Luca; Fullerton, Janice M; Rasser, Paul; Schall, Ulrich; Henskens, Frans; Michie, Patricia T; Loughland, Carmel; Catts, Stanley V; Mowry, Bryan; Weickert, Thomas W; Shannon Weickert, Cynthia; Carr, Vaughan; Lenroot, Rhoshel; Pantelis, Christos; Zalesky, Andrew

    2016-08-17

    White matter abnormalities associated with schizophrenia have been widely reported, although the consistency of findings across studies is moderate. In this study, neuroimaging was used to investigate white matter pathology and its impact on whole-brain white matter connectivity in one of the largest samples of patients with schizophrenia. Fractional anisotropy (FA) and mean diffusivity (MD) were compared between patients with schizophrenia or schizoaffective disorder (n = 326) and age-matched healthy controls (n = 197). Between-group differences in FA and MD were assessed using voxel-based analysis and permutation testing. Automated whole-brain white matter fiber tracking and the network-based statistic were used to characterize the impact of white matter pathology on the connectome and its rich club. Significant reductions in FA associated with schizophrenia were widespread, encompassing more than 40% (234ml) of cerebral white matter by volume and involving all cerebral lobes. Significant increases in MD were also widespread and distributed similarly. The corpus callosum, cingulum, and thalamic radiations exhibited the most extensive pathology according to effect size. More than 50% of cortico-cortical and cortico-subcortical white matter fiber bundles comprising the connectome were disrupted in schizophrenia. Connections between hub regions comprising the rich club were disproportionately affected. Pathology did not differ between patients with schizophrenia and schizoaffective disorder and was not mediated by medication. In conclusion, although connectivity between cerebral hubs is most extensively disturbed in schizophrenia, white matter pathology is widespread, affecting all cerebral lobes and the cerebellum, leading to disruptions in the majority of the brain's fiber bundles.

  20. Hubs of Anticorrelation in High-Resolution Resting-State Functional Connectivity Network Architecture.

    PubMed

    Gopinath, Kaundinya; Krishnamurthy, Venkatagiri; Cabanban, Romeo; Crosson, Bruce A

    2015-06-01

    A major focus of brain research recently has been to map the resting-state functional connectivity (rsFC) network architecture of the normal brain and pathology through functional magnetic resonance imaging. However, the phenomenon of anticorrelations in resting-state signals between different brain regions has not been adequately examined. The preponderance of studies on resting-state fMRI (rsFMRI) have either ignored anticorrelations in rsFC networks or adopted methods in data analysis, which have rendered anticorrelations in rsFC networks uninterpretable. The few studies that have examined anticorrelations in rsFC networks using conventional methods have found anticorrelations to be weak in strength and not very reproducible across subjects. Anticorrelations in rsFC network architecture could reflect mechanisms that subserve a number of important brain processes. In this preliminary study, we examined the properties of anticorrelated rsFC networks by systematically focusing on negative cross-correlation coefficients (CCs) among rsFMRI voxel time series across the brain with graph theory-based network analysis. A number of methods were implemented to enhance the neuronal specificity of resting-state functional connections that yield negative CCs, although at the cost of decreased sensitivity. Hubs of anticorrelation were seen in a number of cortical and subcortical brain regions. Examination of the anticorrelation maps of these hubs indicated that negative CCs in rsFC network architecture highlight a number of regulatory interactions between brain networks and regions, including reciprocal modulations, suppression, inhibition, and neurofeedback.

  1. The Urban Food Hubs Solution: Building Capacity in Urban Communities

    ERIC Educational Resources Information Center

    O'Hara, Sabine

    2017-01-01

    Access to affordable fresh food is an ongoing challenge for underserved urban neighborhoods across the United States. Several are designated food deserts with no access to a full-service grocery store within a one-mile radius. The Urban Food Hubs of the College of Agriculture, Urban Sustainability, and Environmental Sciences (CAUSES) of the…

  2. Natural Gas Market Centers and Hubs: A 2003 Update

    EIA Publications

    2003-01-01

    This special report looks at the current status of market centers/hubs in today's natural gas marketplace, examining their role and their importance to natural gas shippers, marketers, pipelines, and others involved in the transportation of natural gas over the North American pipeline network.

  3. Native Avatars, Online Hubs, and Urban Indian Literature

    ERIC Educational Resources Information Center

    Estrada, Gabriel S.

    2011-01-01

    Teaching American Indian literature with online resources can help diverse urban Indian and multicultural students connect with American Indian cultures, histories, and Nations. This online-enriched pedagogy adopts Susan Lobo's sense of the city as an "urban hub," or activist community center, an urban area linked to reservations in which Native…

  4. The Competitive Position of Hub Airports in the Transatlantic Market

    NASA Technical Reports Server (NTRS)

    Burghouwt, Guillaume; Veldhuis, Jan

    2006-01-01

    This article puts forward the argument that the measurement of connectivity in hub-and-spoke networks has to take into account the quality and quantity of both direct and indirect connections. The NETSCAN model, which has been applied in this study, quantifies indirect connectivity and scales it into a theoretical direct connection. NETSCAN allows researchers, airports, airlines, alliances and airport regions to analyse their competitive position in an integrated way. Using NETSCAN, the authors analysed the developments on the market between northwest Europe and the United States (US) between May 2003 and May 2005. One of the most striking developments has certainly been the impact of the Air France-KLM merger and the effects of the integration of KLM and Northwest into the SkyTeam alliance on the connectivity of Amsterdam Schiphol. Direct as well as indirect connectivity (via European and North American hubs) from Amsterdam to the US increased substantially. The main reason for this increase is the integration of the former Wings and SkyTeam networks via the respective hub airports. Moreover, the extended SkyTeam alliance raised frequencies between Amsterdam and the SkyTeam hubs (Atlanta, Houston, for example), opened new routes (Cincinnati) and boosted the network between Amsterdam and France. As a result of the new routes and frequencies, Amsterdam took over Heathrow s position as the third best-connected northwest European airport to the US.

  5. Comparative assembly hubs: Web-accessible browsers for comparative genomics

    PubMed Central

    Nguyen, Ngan; Hickey, Glenn; Raney, Brian J.; Armstrong, Joel; Clawson, Hiram; Zweig, Ann; Karolchik, Donna; Kent, William James; Haussler, David; Paten, Benedict

    2014-01-01

    Motivation: Researchers now have access to large volumes of genome sequences for comparative analysis, some generated by the plethora of public sequencing projects and, increasingly, from individual efforts. It is not possible, or necessarily desirable, that the public genome browsers attempt to curate all these data. Instead, a wealth of powerful tools is emerging to empower users to create their own visualizations and browsers. Results: We introduce a pipeline to easily generate collections of Web-accessible UCSC Genome Browsers interrelated by an alignment. It is intended to democratize our comparative genomic browser resources, serving the broad and growing community of evolutionary genomicists and facilitating easy public sharing via the Internet. Using the alignment, all annotations and the alignment itself can be efficiently viewed with reference to any genome in the collection, symmetrically. A new, intelligently scaled alignment display makes it simple to view all changes between the genomes at all levels of resolution, from substitutions to complex structural rearrangements, including duplications. To demonstrate this work, we create a comparative assembly hub containing 57 Escherichia coli and 9 Shigella genomes and show examples that highlight their unique biology. Availability and implementation: The source code is available as open source at: https://github.com/glennhickey/progressiveCactus The E.coli and Shigella genome hub is now a public hub listed on the UCSC browser public hubs Web page. Contact: benedict@soe.ucsc.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25138168

  6. Native Avatars, Online Hubs, and Urban Indian Literature

    ERIC Educational Resources Information Center

    Estrada, Gabriel S.

    2011-01-01

    Teaching American Indian literature with online resources can help diverse urban Indian and multicultural students connect with American Indian cultures, histories, and Nations. This online-enriched pedagogy adopts Susan Lobo's sense of the city as an "urban hub," or activist community center, an urban area linked to reservations in which Native…

  7. Discovering Authorities and Hubs in Different Topological Web Graph Structures.

    ERIC Educational Resources Information Center

    Meghabghab, George

    2002-01-01

    Discussion of citation analysis on the Web considers Web hyperlinks as a source to analyze citations. Topics include basic graph theory applied to Web pages, including matrices, linear algebra, and Web topology; and hubs and authorities, including a search technique called HITS (Hyperlink Induced Topic Search). (Author/LRW)

  8. University Strives to Be a Cultural Hub in Central Arkansas

    ERIC Educational Resources Information Center

    Mooney, Carolyn

    2009-01-01

    One might not immediately think of Conway, a city of 55,000, as an arts hub. Conway is growing and changing, and the university's artistic aspirations have played a role. In recent years the University of Central Arkansas, a campus of 13,000 students, has become home to two prestigious literary magazines: (1) "Oxford American"; and (2)…

  9. Discovering Authorities and Hubs in Different Topological Web Graph Structures.

    ERIC Educational Resources Information Center

    Meghabghab, George

    2002-01-01

    Discussion of citation analysis on the Web considers Web hyperlinks as a source to analyze citations. Topics include basic graph theory applied to Web pages, including matrices, linear algebra, and Web topology; and hubs and authorities, including a search technique called HITS (Hyperlink Induced Topic Search). (Author/LRW)

  10. Hierarchical Organization of Human Cortical Networks in Health and Schizophrenia

    PubMed Central

    Bassett, Danielle S.; Bullmore, Edward; Verchinski, Beth A.; Mattay, Venkata S.; Weinberger, Daniel R.; Meyer-Lindenberg, Andreas

    2009-01-01

    The complex organization of connectivity in the human brain is incompletely understood. Recently, topological measures based on graph theory have provided a new approach to quantify large-scale cortical networks. These methods have been applied to anatomical connectivity data on non-human species and cortical networks have been shown to have small-world topology, associated with high local and global efficiency of information transfer. Anatomical networks derived from cortical thickness measurements have shown the same organizational properties of the healthy human brain, consistent with similar results reported in functional networks derived from resting state functional MRI and MEG data. Here we show, using anatomical networks derived from analysis of inter-regional covariation of gray matter volume in magnetic resonance imaging (MRI) data on 259 healthy volunteers, that classical divisions of cortex (multimodal, unimodal and transmodal) have some distinct topological attributes. While all cortical divisions shared non-random properties of small-worldness and efficient wiring (short mean Euclidean distance between connected regions), the multimodal network had a hierarchical organization, dominated by frontal hubs with low clustering, whereas the transmodal network was assortative. Moreover, in a sample of 203 people with schizophrenia, multimodal network organization was abnormal, as indicated by reduced hierarchy, the loss of frontal and the emergence of non-frontal hubs, and increased connection distance. We propose that the topological differences between divisions of normal cortex may represent the outcome of different growth processes for multimodal and transmodal networks; and that neurodevelopmental abnormalities in schizophrenia specifically impact multimodal cortical organization. PMID:18784304

  11. Energy Innovation Hubs: A Home for Scientific Collaboration

    SciTech Connect

    Chu, Steven

    2012-01-01

    Secretary Chu will host a live, streaming Q&A session with the directors of the Energy Innovation Hubs on Tuesday, March 6, at 2:15 p.m. EST. The directors will be available for questions regarding their teams' work and the future of American energy. Ask your questions in the comments below, or submit them on Facebook, Twitter (@energy), or send an e-mail to newmedia@hq.doe.gov, prior or during the live event. Dr. Hank Foley is the director of the Greater Philadelphia Innovation Cluster for Energy-Efficient Buildings, which is pioneering new data intensive techniques for designing and operating energy efficient buildings, including advanced computer modeling. Dr. Douglas Kothe is the director of the Consortium for Advanced Simulation of Light Water Reactors, which uses powerful supercomputers to create "virtual" reactors that will help improve the safety and performance of both existing and new nuclear reactors. Dr. Nathan Lewis is the director of the Joint Center for Artificial Photosynthesis, which focuses on how to produce fuels from sunlight, water, and carbon dioxide. The Energy Innovation Hubs are major integrated research centers, with researchers from many different institutions and technical backgrounds. Each hub is focused on a specific high priority goal, rapidly accelerating scientific discoveries and shortening the path from laboratory innovation to technological development and commercial deployment of critical energy technologies. Ask your questions in the comments below, or submit them on Facebook, Twitter (@energy), or send an e-mail to newmedia@energy.gov, prior or during the live event. The Energy Innovation Hubs are major integrated research centers, with researchers from many different institutions and technical backgrounds. Each Hub is focused on a specific high priority goal, rapidly accelerating scientific discoveries and shortening the path from laboratory innovation to technological development and commercial deployment of critical energy

  12. Energy Innovation Hubs: A Home for Scientific Collaboration

    ScienceCinema

    Chu, Steven

    2016-07-12

    Secretary Chu will host a live, streaming Q&A session with the directors of the Energy Innovation Hubs on Tuesday, March 6, at 2:15 p.m. EST. The directors will be available for questions regarding their teams' work and the future of American energy. Ask your questions in the comments below, or submit them on Facebook, Twitter (@energy), or send an e-mail to newmedia@hq.doe.gov, prior or during the live event. Dr. Hank Foley is the director of the Greater Philadelphia Innovation Cluster for Energy-Efficient Buildings, which is pioneering new data intensive techniques for designing and operating energy efficient buildings, including advanced computer modeling. Dr. Douglas Kothe is the director of the Consortium for Advanced Simulation of Light Water Reactors, which uses powerful supercomputers to create "virtual" reactors that will help improve the safety and performance of both existing and new nuclear reactors. Dr. Nathan Lewis is the director of the Joint Center for Artificial Photosynthesis, which focuses on how to produce fuels from sunlight, water, and carbon dioxide. The Energy Innovation Hubs are major integrated research centers, with researchers from many different institutions and technical backgrounds. Each hub is focused on a specific high priority goal, rapidly accelerating scientific discoveries and shortening the path from laboratory innovation to technological development and commercial deployment of critical energy technologies. Ask your questions in the comments below, or submit them on Facebook, Twitter (@energy), or send an e-mail to newmedia@energy.gov, prior or during the live event. The Energy Innovation Hubs are major integrated research centers, with researchers from many different institutions and technical backgrounds. Each Hub is focused on a specific high priority goal, rapidly accelerating scientific discoveries and shortening the path from laboratory innovation to technological development and commercial deployment of critical energy

  13. Multiple Hub Network Choice in the Liberalized European Market

    NASA Technical Reports Server (NTRS)

    Berechman, Joseph; deWit, Jaap

    1997-01-01

    A key question that so far has received relatively little attention in the germane literature is that of the changes at various airports as a result of the EU liberalization policies. That is, presently, most major European airports still benefit from the so-called home-carrier phenomenon where the country's publicly or semi-publicly owned carrier uses the country's main airport as its gateway hub and, consequently, the home-carrier is also the principal user of this airport (in terms of proportion of total aircraft movements, number of passengers transported, connections, slots ownership, etc.). The country's main airport has substantially benefited from these monopoly conditions of airline captivity, strongly determined by the bilateral system of international air transport regulation. Therefore, European major airports were used to operate in essentially different markets, compared to the increasingly competitive markets of their home based carriers. This partly explains relative stability of transport volumes and financial results of European major airports compared to the relatively volatile financial results of most European national airlines. However, the liberalization of European aviation is likely to change this situation. Market access is open now to all community carriers, i.e. carriers with majority ownership and effective control in the hands of EU citizens. Ticket prices are free, governments can only intervene in case of dumping or excessive pricing. A community airline can choose its seat in any of the 15 member states. Licensing procedures are harmonized between member states. In the last few months community carriers have had unrestricted route access within the EU. Most probably this development will be extended to countries inside and outside Europe. Last year the European Commission got the mandate to start negotiations with 10 other European countries. In the meantime the EC has also started negotiations with the USA on so-called soft rights

  14. Statistical Approaches for Gene Selection, Hub Gene Identification and Module Interaction in Gene Co-Expression Network Analysis: An Application to Aluminum Stress in Soybean (Glycine max L.)

    PubMed Central

    Das, Samarendra; Meher, Prabina Kumar; Bhar, Lal Mohan; Mandal, Baidya Nath

    2017-01-01

    Selection of informative genes is an important problem in gene expression studies. The small sample size and the large number of genes in gene expression data make the selection process complex. Further, the selected informative genes may act as a vital input for gene co-expression network analysis. Moreover, the identification of hub genes and module interactions in gene co-expression networks is yet to be fully explored. This paper presents a statistically sound gene selection technique based on support vector machine algorithm for selecting informative genes from high dimensional gene expression data. Also, an attempt has been made to develop a statistical approach for identification of hub genes in the gene co-expression network. Besides, a differential hub gene analysis approach has also been developed to group the identified hub genes into various groups based on their gene connectivity in a case vs. control study. Based on this proposed approach, an R package, i.e., dhga (https://cran.r-project.org/web/packages/dhga) has been developed. The comparative performance of the proposed gene selection technique as well as hub gene identification approach was evaluated on three different crop microarray datasets. The proposed gene selection technique outperformed most of the existing techniques for selecting robust set of informative genes. Based on the proposed hub gene identification approach, a few number of hub genes were identified as compared to the existing approach, which is in accordance with the principle of scale free property of real networks. In this study, some key genes along with their Arabidopsis orthologs has been reported, which can be used for Aluminum toxic stress response engineering in soybean. The functional analysis of various selected key genes revealed the underlying molecular mechanisms of Aluminum toxic stress response in soybean. PMID:28056073

  15. Statistical Approaches for Gene Selection, Hub Gene Identification and Module Interaction in Gene Co-Expression Network Analysis: An Application to Aluminum Stress in Soybean (Glycine max L.).

    PubMed

    Das, Samarendra; Meher, Prabina Kumar; Rai, Anil; Bhar, Lal Mohan; Mandal, Baidya Nath

    2017-01-01

    Selection of informative genes is an important problem in gene expression studies. The small sample size and the large number of genes in gene expression data make the selection process complex. Further, the selected informative genes may act as a vital input for gene co-expression network analysis. Moreover, the identification of hub genes and module interactions in gene co-expression networks is yet to be fully explored. This paper presents a statistically sound gene selection technique based on support vector machine algorithm for selecting informative genes from high dimensional gene expression data. Also, an attempt has been made to develop a statistical approach for identification of hub genes in the gene co-expression network. Besides, a differential hub gene analysis approach has also been developed to group the identified hub genes into various groups based on their gene connectivity in a case vs. control study. Based on this proposed approach, an R package, i.e., dhga (https://cran.r-project.org/web/packages/dhga) has been developed. The comparative performance of the proposed gene selection technique as well as hub gene identification approach was evaluated on three different crop microarray datasets. The proposed gene selection technique outperformed most of the existing techniques for selecting robust set of informative genes. Based on the proposed hub gene identification approach, a few number of hub genes were identified as compared to the existing approach, which is in accordance with the principle of scale free property of real networks. In this study, some key genes along with their Arabidopsis orthologs has been reported, which can be used for Aluminum toxic stress response engineering in soybean. The functional analysis of various selected key genes revealed the underlying molecular mechanisms of Aluminum toxic stress response in soybean.

  16. Cortical microtubule-associated ER sites: organization centers of cell polarity and communication.

    PubMed

    Peña, Eduardo José; Heinlein, Manfred

    2013-12-01

    Anisotropic cell growth and the ability of plant cells to communicate within and across the borders of cellular and supracellular domains depends on the ability of the cells to dynamically establish polarized networks able to deliver structural and informational macromolecules to distinct cellular sites. Studies of organelle movements and transport of endogenous and viral proteins suggest that organelle and macromolecular trafficking pathways involve transient or stable interactions with cortical microtubule-associated endoplasmic reticulum sites (C-MERs). The observations suggest that C-MERs may function as cortical hubs that organize cargo exchange between organelles and allow the recruitment, assembly, and subsequently site-specific delivery of macromolecular complexes. We propose that viruses interact with such hubs for replication and intercellular spread. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. New Burns Centre in Parma Hospital, West Emilia Hub

    PubMed Central

    Caleffi, E.; Bocchi, A.; Soncini, I.; Arena, A.

    2008-01-01

    Summary Parma Hospital is the Trauma Centre for SIAT (Trauma Patients Integrated Assistance System) in the West Emilia District in the regional trauma patient project. SIAT's goal is to provide the quickest and most appropriate treatment in major trauma patients. Extensive burns are a multi-organ pathology, i.e. a major life-threatening trauma. Our burn patients are treated on the "Hub and Spoke" model: triage and immediate transfer from the Spoke (first- and second-level Centre) to the Hub (third-level centre, i.e. the Parma Hospital Burns Centre). Burn treatment requires pre-hospital care (timely assistance, airways security, steady life parameters, adequate central or peripheral access, fluid administration, maintenance of body temperature, transport) and adequate hospital treatment (fluid resuscitation, pain therapy, gastroduodenal ulceration prophylaxis, escharotomies, and topical wound care). PMID:21991130

  18. Spectral Analysis of the Wake behind a Helicopter Rotor Hub

    NASA Astrophysics Data System (ADS)

    Petrin, Christopher; Reich, David; Schmitz, Sven; Elbing, Brian

    2016-11-01

    A scaled model of a notional helicopter rotor hub was tested in the 48" Garfield Thomas Water Tunnel at the Applied Research Laboratory Penn State. LDV and PIV measurements in the far-wake consistently showed a six-per-revolution flow structure, in addition to stronger two- and four-per-revolution structures. These six-per-revolution structures persisted into the far-field, and have no direct geometric counterpart on the hub model. The current study will examine the Reynolds number dependence of these structures and present higher-order statistics of the turbulence within the wake. In addition, current activity using the EFPL Large Water Tunnel at Oklahoma State University will be presented. This effort uses a more canonical configuration to identify the source for these six-per-revolution structures, which are assumed to be a non-linear interaction between the two- and four-per-revolution structures.

  19. The deep-sea hub of the ANTARES neutrino telescope

    NASA Astrophysics Data System (ADS)

    Anghinolfi, M.; Calzas, A.; Dinkespiler, B.; Cuneo, S.; Favard, S.; Hallewell, G.; Jaquet, M.; Musumeci, M.; Papaleo, R.; Raia, G.; Valdy, P.; Vernin, P.

    2006-11-01

    The ANTARES neutrino telescope, currently under construction at 2500 m depth off the French Mediterranean coast, will contain 12 detection lines, powered and read out through a deep-sea junction box (JB) hub. Electrical energy from the shore station is distributed through a transformer with multiple secondary windings and a plugboard with 16 deep sea-mateable electro-optic connectors. Connections are made to the JB outputs using manned or remotely operated submersible vehicles. The triply redundant power management and slow control system is based on two identical AC-powered systems, communicating with the shore through 160 Mb/s fibre G-links and a third battery-powered system using a slower link. We describe the power and slow control systems of the underwater hub.

  20. Compound Hub: efficiency gains through innovative sample management processes.

    PubMed

    Schopfer, Ulrich; Andreae, Marc R M; Hueber, Matthieu; Saur, Andreas; Kummer, Marcel O; Girod, Michel; Fox, Desmond; Steiner, Thomas; Popov, Maxim; Smith, Robert

    2007-05-01

    While significant investments are made across the industry and increasingly also in academia to enhance or build a compound file, the efficient sourcing of compounds from in-house medical chemistry is frequently seen as a challenge. This article introduces the Compound Hub strategy developed at the Novartis Compound Archive. Central Compound Hubs in Basel and Cambridge were combined with web-based ordering of compounds and assays, providing assay-ready, solubilized samples to labs anywhere in the global research organization. Relieving scientists from time-intensive sample preparation tasks, error rates could be reduced through electronic processing and tracking of compounds/assays and the capture of medicinal chemistry compounds for the compound library could be increased by 75%.

  1. Digital microfluidic hub for automated nucleic acid sample preparation.

    SciTech Connect

    He, Jim; Bartsch, Michael S.; Patel, Kamlesh D.; Kittlaus, Eric A.; Remillared, Erin M.; Pezzola, Genevieve L.; Renzi, Ronald F.; Kim, Hanyoup

    2010-07-01

    We have designed, fabricated, and characterized a digital microfluidic (DMF) platform to function as a central hub for interfacing multiple lab-on-a-chip sample processing modules towards automating the preparation of clinically-derived DNA samples for ultrahigh throughput sequencing (UHTS). The platform enables plug-and-play installation of a two-plate DMF device with consistent spacing, offers flexible connectivity for transferring samples between modules, and uses an intuitive programmable interface to control droplet/electrode actuations. Additionally, the hub platform uses transparent indium-tin oxide (ITO) electrodes to allow complete top and bottom optical access to the droplets on the DMF array, providing additional flexibility for various detection schemes.

  2. Genetic Animal Models of Malformations of Cortical Development and Epilepsy

    PubMed Central

    Wong, Michael; Roper, Steven N.

    2015-01-01

    Malformations of cortical development constitute a variety of pathological brain abnormalities that commonly cause severe, medically-refractory epilepsy, including focal lesions, such as focal cortical dysplasia, hetereotopias, and tubers of tuberous sclerosis complex, and diffuse malformations, such as lissencephaly. Although some cortical malformations result from environmental insults during cortical development in utero, genetic factors are increasingly recognized as primary pathogenic factors across the entire spectrum of malformations. Genes implicated in causing different cortical malformations are involved in a variety of physiological functions, but many are focused on regulation of cell proliferation, differentiation, and neuronal migration. Advances in molecular genetic methods have allowed the engineering of increasingly sophisticated animal models of cortical malformations and associated epilepsy. These animal models have identified some common mechanistic themes shared by a number of different cortical malformations, but also revealed the diversity and complexity of cellular and molecular mechanisms that lead to the development of the pathological lesions and resulting epileptogenesis. PMID:25911067

  3. Hub River: A private power prototype. [Independent Power Production

    SciTech Connect

    Sachs, J.L.

    1992-10-01

    This article examines the challenges of financing an independent power project in a developing country. The oil-fired plant is to be located on the Hub River in Baluchistan on the Arabian Sea coast. The topics of the article include a description of the team that put the project together, the financing plans, the risk in the face of political unrest and change of governments, and the beginning of construction of the project.

  4. The home hemodialysis hub: physical infrastructure and integrated governance structure.

    PubMed

    Marshall, Mark R; Young, Bessie A; Fox, Sally J; Cleland, Calli J; Walker, Robert J; Masakane, Ikuto; Herold, Aaron M

    2015-04-01

    An effective home hemodialysis program critically depends on adequate hub facilities and support functions and on transparent and accountable organizational processes. The likelihood of optimal service delivery and patient care will be enhanced by fit-for-purpose facilities and implementation of a well-considered governance structure. In this article, we describe the required accommodation and infrastructure for a home hemodialysis program and a generic organizational structure that will support both patient-facing clinical activities and business processes.

  5. Hub and Spoke Logistics for Maritime Patrol and Reconnaissance Operations

    DTIC Science & Technology

    2011-12-01

    expeditionary power projection as being flexible, scalable, and responsive. This figure also displays the routine operations (RO) tree with branches as...either hubs or spokes. The depicted transition phase shows the crossover from RO to major combat operations (MCO). Within the MCO tree are...shuttle for each time step. Locations labeled with the “BG” suffix are customers, thus their available amounts of each commodity decrease after each

  6. Location of an intermediate hub for port activities

    NASA Astrophysics Data System (ADS)

    Burciu, Ş.; Ştefănică, C.; Roşca, E.; Dragu, V.; Ruscă, F.

    2015-11-01

    An intermediate hub might increase the accessibility level of ports but also hinterland and so it can be considered more than a facility with a transhipment role. These hubs might lead to the development of other transport services and enhance their role in gathering and covering economic centres within hinterlands and also getting the part of logistic facility for the ports, with effects on port utilization and its connectivity to global economy. A new location for a hub terminal leads to reduced transport distances within hinterland, with decreased transport costs and external effects, so with gains in people's life quality. Because the production and distribution systems are relatively fixed on short and medium term and the location decisions are strategic and on long term, the logistic chains activities location models have to consider the uncertainties regarding the possible future situations. In most models, production costs are considered equal, the location problem reducing itself to a problem that aims to minimize the total transport costs, meaning the transport problem. The main objective of the paper is to locate a hub terminal that links the producers of cereals that are going to be exported by naval transportation with the Romanian fluvial-maritime ports (Galaţi, Brăila). GIS environment can be used to integrate and analyse a great amount of data and has the ability of using functions as location - allocation models necessary both to private and public sector, being able to determine the optimal location for services like factories, warehouses, logistic platforms and other public services.

  7. Hub-Centered Gene Network Reconstruction Using Automatic Relevance Determination

    PubMed Central

    Böck, Matthias; Ogishima, Soichi; Tanaka, Hiroshi; Kramer, Stefan; Kaderali, Lars

    2012-01-01

    Network inference deals with the reconstruction of biological networks from experimental data. A variety of different reverse engineering techniques are available; they differ in the underlying assumptions and mathematical models used. One common problem for all approaches stems from the complexity of the task, due to the combinatorial explosion of different network topologies for increasing network size. To handle this problem, constraints are frequently used, for example on the node degree, number of edges, or constraints on regulation functions between network components. We propose to exploit topological considerations in the inference of gene regulatory networks. Such systems are often controlled by a small number of hub genes, while most other genes have only limited influence on the network's dynamic. We model gene regulation using a Bayesian network with discrete, Boolean nodes. A hierarchical prior is employed to identify hub genes. The first layer of the prior is used to regularize weights on edges emanating from one specific node. A second prior on hyperparameters controls the magnitude of the former regularization for different nodes. The net effect is that central nodes tend to form in reconstructed networks. Network reconstruction is then performed by maximization of or sampling from the posterior distribution. We evaluate our approach on simulated and real experimental data, indicating that we can reconstruct main regulatory interactions from the data. We furthermore compare our approach to other state-of-the art methods, showing superior performance in identifying hubs. Using a large publicly available dataset of over 800 cell cycle regulated genes, we are able to identify several main hub genes. Our method may thus provide a valuable tool to identify interesting candidate genes for further study. Furthermore, the approach presented may stimulate further developments in regularization methods for network reconstruction from data. PMID:22570688

  8. The coffee genome hub: a resource for coffee genomes

    PubMed Central

    Dereeper, Alexis; Bocs, Stéphanie; Rouard, Mathieu; Guignon, Valentin; Ravel, Sébastien; Tranchant-Dubreuil, Christine; Poncet, Valérie; Garsmeur, Olivier; Lashermes, Philippe; Droc, Gaëtan

    2015-01-01

    The whole genome sequence of Coffea canephora, the perennial diploid species known as Robusta, has been recently released. In the context of the C. canephora genome sequencing project and to support post-genomics efforts, we developed the Coffee Genome Hub (http://coffee-genome.org/), an integrative genome information system that allows centralized access to genomics and genetics data and analysis tools to facilitate translational and applied research in coffee. We provide the complete genome sequence of C. canephora along with gene structure, gene product information, metabolism, gene families, transcriptomics, syntenic blocks, genetic markers and genetic maps. The hub relies on generic software (e.g. GMOD tools) for easy querying, visualizing and downloading research data. It includes a Genome Browser enhanced by a Community Annotation System, enabling the improvement of automatic gene annotation through an annotation editor. In addition, the hub aims at developing interoperability among other existing South Green tools managing coffee data (phylogenomics resources, SNPs) and/or supporting data analyses with the Galaxy workflow manager. PMID:25392413

  9. Spider orientation and hub position in orb webs

    NASA Astrophysics Data System (ADS)

    Zschokke, Samuel; Nakata, Kensuke

    2010-01-01

    Orb-web building spiders (Araneae: Araneoidea, Uloboridae) can be considered as territorial central place foragers. In territorial central place foragers, the optimal foraging arena is circular, with the forager sitting in its centre. In orb webs, the spider’s orientation (head up or head down) whilst waiting for prey on the hub of its web and the downwards-upwards asymmetry of its running speeds are the probable causes for the observed deviation of the hub from the web’s centre. Here, we present an analytical model and a more refined simulation model to analyse the relationships amongst the spider’s running speeds, its orientation whilst waiting for prey and the vertical asymmetry of orb webs. The results of our models suggest that (a) waiting for prey head down is generally favourable because it allows the spider to reach the prey in its web on average quicker than spiders waiting head up, (b) the downwards-upwards running speed asymmetry, together with the head-down orientation of most spiders, are likely causes for the observed vertical asymmetry of orb webs, (c) waiting head up can be advantageous for spiders whose downwards-upwards running speed asymmetry is small and who experience high prey tumbling rates and (d) spiders waiting head up should place their hub lower than similar spiders waiting head down.

  10. Mapping Multiplex Hubs in Human Functional Brain Networks

    PubMed Central

    De Domenico, Manlio; Sasai, Shuntaro; Arenas, Alex

    2016-01-01

    Typical brain networks consist of many peripheral regions and a few highly central ones, i.e., hubs, playing key functional roles in cerebral inter-regional interactions. Studies have shown that networks, obtained from the analysis of specific frequency components of brain activity, present peculiar architectures with unique profiles of region centrality. However, the identification of hubs in networks built from different frequency bands simultaneously is still a challenging problem, remaining largely unexplored. Here we identify each frequency component with one layer of a multiplex network and face this challenge by exploiting the recent advances in the analysis of multiplex topologies. First, we show that each frequency band carries unique topological information, fundamental to accurately model brain functional networks. We then demonstrate that hubs in the multiplex network, in general different from those ones obtained after discarding or aggregating the measured signals as usual, provide a more accurate map of brain's most important functional regions, allowing to distinguish between healthy and schizophrenic populations better than conventional network approaches. PMID:27471443

  11. Publishing and sharing of hydrologic models through WaterHUB

    NASA Astrophysics Data System (ADS)

    Merwade, V.; Ruddell, B. L.; Song, C.; Zhao, L.; Kim, J.; Assi, A.

    2011-12-01

    Most hydrologists use hydrologic models to simulate the hydrologic processes to understand hydrologic pathways and fluxes for research, decision making and engineering design. Once these tasks are complete including publication of results, the models generally are not published or made available to the public for further use and improvement. Although publication or sharing of models is not required for journal publications, sharing of models may open doors for new collaborations, and avoids duplication of efforts if other researchers are interested in simulating a particular watershed for which a model already exists. For researchers, who are interested in sharing models, there are limited avenues to publishing their models to the wider community. Towards filling this gap, a prototype cyberinfrastructure (CI), called WaterHUB, is developed for sharing hydrologic data and modeling tools in an interactive environment. To test the utility of WaterHUB for sharing hydrologic models, a system to publish and share SWAT (Soil Water Assessment Tool) is developed. Users can utilize WaterHUB to search and download existing SWAT models, and also upload new SWAT models. Metadata such as the name of the watershed, name of the person or agency who developed the model, simulation period, time step, and list of calibrated parameters also published with individual model.

  12. The coffee genome hub: a resource for coffee genomes.

    PubMed

    Dereeper, Alexis; Bocs, Stéphanie; Rouard, Mathieu; Guignon, Valentin; Ravel, Sébastien; Tranchant-Dubreuil, Christine; Poncet, Valérie; Garsmeur, Olivier; Lashermes, Philippe; Droc, Gaëtan

    2015-01-01

    The whole genome sequence of Coffea canephora, the perennial diploid species known as Robusta, has been recently released. In the context of the C. canephora genome sequencing project and to support post-genomics efforts, we developed the Coffee Genome Hub (http://coffee-genome.org/), an integrative genome information system that allows centralized access to genomics and genetics data and analysis tools to facilitate translational and applied research in coffee. We provide the complete genome sequence of C. canephora along with gene structure, gene product information, metabolism, gene families, transcriptomics, syntenic blocks, genetic markers and genetic maps. The hub relies on generic software (e.g. GMOD tools) for easy querying, visualizing and downloading research data. It includes a Genome Browser enhanced by a Community Annotation System, enabling the improvement of automatic gene annotation through an annotation editor. In addition, the hub aims at developing interoperability among other existing South Green tools managing coffee data (phylogenomics resources, SNPs) and/or supporting data analyses with the Galaxy workflow manager. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  13. Features analysis for identification of date and party hubs in protein interaction network of Saccharomyces Cerevisiae.

    PubMed

    Mirzarezaee, Mitra; Araabi, Babak N; Sadeghi, Mehdi

    2010-12-19

    It has been understood that biological networks have modular organizations which are the sources of their observed complexity. Analysis of networks and motifs has shown that two types of hubs, party hubs and date hubs, are responsible for this complexity. Party hubs are local coordinators because of their high co-expressions with their partners, whereas date hubs display low co-expressions and are assumed as global connectors. However there is no mutual agreement on these concepts in related literature with different studies reporting their results on different data sets. We investigated whether there is a relation between the biological features of Saccharomyces Cerevisiae's proteins and their roles as non-hubs, intermediately connected, party hubs, and date hubs. We propose a classifier that separates these four classes. We extracted different biological characteristics including amino acid sequences, domain contents, repeated domains, functional categories, biological processes, cellular compartments, disordered regions, and position specific scoring matrix from various sources. Several classifiers are examined and the best feature-sets based on average correct classification rate and correlation coefficients of the results are selected. We show that fusion of five feature-sets including domains, Position Specific Scoring Matrix-400, cellular compartments level one, and composition pairs with two and one gaps provide the best discrimination with an average correct classification rate of 77%. We study a variety of known biological feature-sets of the proteins and show that there is a relation between domains, Position Specific Scoring Matrix-400, cellular compartments level one, composition pairs with two and one gaps of Saccharomyces Cerevisiae's proteins, and their roles in the protein interaction network as non-hubs, intermediately connected, party hubs and date hubs. This study also confirms the possibility of predicting non-hubs, party hubs and date hubs

  14. A hub dynamometer for measurement of wheel forces in off-road bicycling.

    PubMed

    De Lorenzo, D S; Hull, M L

    1999-02-01

    A dynamometric hubset that measures the two ground contact force components acting on a bicycle wheel in the plane of the bicycle during off-road riding while either coasting or braking was designed, constructed, and evaluated. To maintain compatibility with standard mountain bike construction, the hubs use commercially available shells with modified, strain gage-equipped axles. The axle strain gages are sensitive to forces acting in the radial and tangential directions, while minimizing sensitivity to transverse forces, steering moments, and variations in the lateral location of the center of pressure. Static calibration and a subsequent accuracy check that computed differences between applied and apparent loads developed during coasting revealed root mean squared errors of 1 percent full-scale or less (full-scale load = 4500 N). The natural frequency of the rear hub with the wheel attached exceeded 350 Hz. These performance capabilities make the dynamometer useful for its intended purpose during coasting. To demonstrate this usefulness, sample ground contact forces are presented for a subject who coasted downhill over rough terrain. The dynamometric hubset can also be used to determine ground contact forces during braking providing that the brake reaction force components are known. However, compliance of the fork can lead to high cross-sensitivity and corresponding large (> 5 percent FS) measurement errors at the front wheel.

  15. Caulobacter PopZ forms an intrinsically disordered hub in organizing bacterial cell poles

    PubMed Central

    Holmes, Joshua A.; Follett, Shelby E.; Wang, Haibi; Meadows, Christopher P.; Varga, Krisztina; Bowman, Grant R.

    2016-01-01

    Despite their relative simplicity, bacteria have complex anatomy at the subcellular level. At the cell poles of Caulobacter crescentus, a 177-amino acid (aa) protein called PopZ self-assembles into 3D polymeric superstructures. Remarkably, we find that this assemblage interacts directly with at least eight different proteins, which are involved in cell cycle regulation and chromosome segregation. The binding determinants within PopZ include 24 aa at the N terminus, a 32-aa region near the C-terminal homo-oligomeric assembly domain, and portions of an intervening linker region. Together, the N-terminal 133 aa of PopZ are sufficient for interacting with all binding partners, even in the absence of homo-oligomeric assembly. Structural analysis of this region revealed that it is intrinsically disordered, similar to p53 and other hub proteins that organize complex signaling networks in eukaryotic cells. Through live-cell photobleaching, we find rapid binding kinetics between PopZ and its partners, suggesting many pole-localized proteins become concentrated at cell poles through rapid cycles of binding and unbinding within the PopZ scaffold. We conclude that some bacteria, similar to their eukaryotic counterparts, use intrinsically disordered hub proteins for network assembly and subcellular organization. PMID:27791060

  16. Connecting myelin-related and synaptic dysfunction in schizophrenia with SNP-rich gene expression hubs

    PubMed Central

    Hegyi, Hedi

    2017-01-01

    Combining genome-wide mapping of SNP-rich regions in schizophrenics and gene expression data in all brain compartments across the human life span revealed that genes with promoters most frequently mutated in schizophrenia are expression hubs interacting with far more genes than the rest of the genome. We summed up the differentially methylated “expression neighbors” of genes that fall into one of 108 distinct schizophrenia-associated loci with high number of SNPs. Surprisingly, the number of expression neighbors of the genes in these loci were 35 times higher for the positively correlating genes (32 times higher for the negatively correlating ones) than for the rest of the ~16000 genes. While the genes in the 108 loci have little known impact in schizophrenia, we identified many more known schizophrenia-related important genes with a high degree of connectedness (e.g. MOBP, SYNGR1 and DGCR6), validating our approach. Both the most connected positive and negative hubs affected synapse-related genes the most, supporting the synaptic origin of schizophrenia. At least half of the top genes in both the correlating and anti-correlating categories are cancer-related, including oncogenes (RRAS and ALDOA), providing further insight into the observed inverse relationship between the two diseases. PMID:28382934

  17. The Central Amygdala as an Integrative Hub for Anxiety and Alcohol Use Disorders

    PubMed Central

    Gilpin, Nicholas W.; Herman, Melissa A.; Roberto, Marisa

    2014-01-01

    The central amygdala (CeA) plays a central role in physiological and behavioral responses to fearful stimuli, stressful stimuli, and drug-related stimuli. The CeA receives dense inputs from cortical regions, is the major output region of the amygdala, is primarily GABAergic (inhibitory), and expresses high levels of pro- and anti-stress peptides. The CeA is also a constituent region of a conceptual macrostructure called the extended amygdala that is recruited during the transition to alcohol dependence. In this review, we discuss neurotransmission in the CeA as a potential integrative hub between anxiety disorders and Alcohol Use Disorder (AUD), which are commonly co-occurring in humans. Human imaging work and multi-disciplinary work in animals collectively suggest that CeA structure and function are altered in individuals with anxiety disorders and AUD, the end result of which may be disinhibition of downstream “effector” regions that regulate anxiety- and alcohol-related behaviors. PMID:25433901

  18. Cortical High-Density Counterstream Architectures

    PubMed Central

    Markov, Nikola T.; Ercsey-Ravasz, Mária; Van Essen, David C.

    2014-01-01

    Small-world networks provide an appealing description of cortical architecture owing to their capacity for integration and segregation combined with an economy of connectivity. Previous reports of low-density interareal graphs and apparent small-world properties are challenged by data that reveal high-density cortical graphs in which economy of connections is achieved by weight heterogeneity and distance-weight correlations. These properties define a model that predicts many binary and weighted features of the cortical network including a core-periphery, a typical feature of self-organizing information processing systems. Feedback and feedforward pathways between areas exhibit a dual counterstream organization, and their integration into local circuits constrains cortical computation. Here, we propose a bow-tie representation of interareal architecture derived from the hierarchical laminar weights of pathways between the high-efficiency dense core and periphery. PMID:24179228

  19. Cortical high-density counterstream architectures.

    PubMed

    Markov, Nikola T; Ercsey-Ravasz, Mária; Van Essen, David C; Knoblauch, Kenneth; Toroczkai, Zoltán; Kennedy, Henry

    2013-11-01

    Small-world networks provide an appealing description of cortical architecture owing to their capacity for integration and segregation combined with an economy of connectivity. Previous reports of low-density interareal graphs and apparent small-world properties are challenged by data that reveal high-density cortical graphs in which economy of connections is achieved by weight heterogeneity and distance-weight correlations. These properties define a model that predicts many binary and weighted features of the cortical network including a core-periphery, a typical feature of self-organizing information processing systems. Feedback and feedforward pathways between areas exhibit a dual counterstream organization, and their integration into local circuits constrains cortical computation. Here, we propose a bow-tie representation of interareal architecture derived from the hierarchical laminar weights of pathways between the high-efficiency dense core and periphery.

  20. Virtual Hubs for facilitating access to Open Data

    NASA Astrophysics Data System (ADS)

    Mazzetti, Paolo; Latre, Miguel Á.; Ernst, Julia; Brumana, Raffaella; Brauman, Stefan; Nativi, Stefano

    2015-04-01

    In October 2014 the ENERGIC-OD (European NEtwork for Redistributing Geospatial Information to user Communities - Open Data) project, funded by the European Union under the Competitiveness and Innovation framework Programme (CIP), has started. In response to the EU call, the general objective of the project is to "facilitate the use of open (freely available) geographic data from different sources for the creation of innovative applications and services through the creation of Virtual Hubs". In ENERGIC-OD, Virtual Hubs are conceived as information systems supporting the full life cycle of Open Data: publishing, discovery and access. They facilitate the use of Open Data by lowering and possibly removing the main barriers which hampers geo-information (GI) usage by end-users and application developers. Data and data services heterogeneity is recognized as one of the major barriers to Open Data (re-)use. It imposes end-users and developers to spend a lot of effort in accessing different infrastructures and harmonizing datasets. Such heterogeneity cannot be completely removed through the adoption of standard specifications for service interfaces, metadata and data models, since different infrastructures adopt different standards to answer to specific challenges and to address specific use-cases. Thus, beyond a certain extent, heterogeneity is irreducible especially in interdisciplinary contexts. ENERGIC-OD Virtual Hubs address heterogeneity adopting a mediation and brokering approach: specific components (brokers) are dedicated to harmonize service interfaces, metadata and data models, enabling seamless discovery and access to heterogeneous infrastructures and datasets. As an innovation project, ENERGIC-OD will integrate several existing technologies to implement Virtual Hubs as single points of access to geospatial datasets provided by new or existing platforms and infrastructures, including INSPIRE-compliant systems and Copernicus services. ENERGIC OD will deploy a

  1. Evolution of cortical neurogenesis.

    PubMed

    Abdel-Mannan, Omar; Cheung, Amanda F P; Molnár, Zoltán

    2008-03-18

    The neurons of the mammalian neocortex are organised into six layers. By contrast, the reptilian and avian dorsal cortices only have three layers which are thought to be equivalent to layers I, V and VI of mammals. Increased repertoire of mammalian higher cognitive functions is likely a result of an expanded cortical surface area. The majority of cortical cell proliferation in mammals occurs in the ventricular zone (VZ) and subventricular zone (SVZ), with a small number of scattered divisions outside the germinal zone. Comparative developmental studies suggest that the appearance of SVZ coincides with the laminar expansion of the cortex to six layers, as well as the tangential expansion of the cortical sheet seen within mammals. In spite of great variation and further compartmentalisation in the mitotic compartments, the number of neurons in an arbitrary cortical column appears to be remarkably constant within mammals. The current challenge is to understand how the emergence and elaboration of the SVZ has contributed to increased cortical cell diversity, tangential expansion and gyrus formation of the mammalian neocortex. This review discusses neurogenic processes that are believed to underlie these major changes in cortical dimensions in vertebrates.

  2. Scenario-based modeling for multiple allocation hub location problem under disruption risk: multiple cuts Benders decomposition approach

    NASA Astrophysics Data System (ADS)

    Yahyaei, Mohsen; Bashiri, Mahdi

    2017-03-01

    The hub location problem arises in a variety of domains such as transportation and telecommunication systems. In many real-world situations, hub facilities are subject to disruption. This paper deals with the multiple allocation hub location problem in the presence of facilities failure. To model the problem, a two-stage stochastic formulation is developed. In the proposed model, the number of scenarios grows exponentially with the number of facilities. To alleviate this issue, two approaches are applied simultaneously. The first approach is to apply sample average approximation to approximate the two stochastic problem via sampling. Then, by applying the multiple cuts Benders decomposition approach, computational performance is enhanced. Numerical studies show the effective performance of the SAA in terms of optimality gap for small problem instances with numerous scenarios. Moreover, performance of multi-cut Benders decomposition is assessed through comparison with the classic version and the computational results reveal the superiority of the multi-cut approach regarding the computational time and number of iterations.

  3. Abnormal Intrinsic Functional Hubs in Severe Male Obstructive Sleep Apnea: Evidence from a Voxel-Wise Degree Centrality Analysis

    PubMed Central

    Shao, Yi; Gong, Honghan; Zhang, Wei; Zeng, Xianjun; Ye, Chenglong; Nie, Si; Chen, Liting; Peng, Dechang

    2016-01-01

    Purpose Obstructive sleep apnea (OSA) has been associated with changes in brain structure and regional function in certain brain areas. However, the functional features of network organization in the whole brain remain largely uncertain. The purpose of this study was to identify the OSA-related spatial centrality distribution of the whole brain functional network and to investigate the potential altered intrinsic functional hubs. Methods Forty male patients with newly confirmed severe OSA on polysomnography, and well-matched good sleepers, participated in this study. All participants underwent a resting-state functional MRI scan and clinical and cognitive evaluation. Voxel-wise degree centrality (DC) was measured across the whole brain, and group difference in DC was compared. The relationship between the abnormal DC value and clinical variables was assessed using a linear correlation analysis. Results Remarkably similar spatial distributions of the functional hubs (high DC) were found in both groups. However, OSA patients exhibited a pattern of significantly reduced regional DC in the left middle occipital gyrus, posterior cingulate cortex, left superior frontal gyrus, and bilateral inferior parietal lobule, and DC was increased in the right orbital frontal cortex, bilateral cerebellum posterior lobes, and bilateral lentiform nucleus, including the putamen, extending to the hippocampus, and the inferior temporal gyrus, which overlapped with the functional hubs. Furthermore, a linear correlation analysis revealed that the DC value in the posterior cingulate cortex and left superior frontal gyrus were positively correlated with Montreal cognitive assessment scores, The DC value in the left middle occipital gyrus and bilateral inferior parietal lobule were negatively correlated with apnea-hypopnea index and arousal index in OSA patients. Conclusion Our findings suggest that OSA patients exhibited specific abnormal intrinsic functional hubs including relatively

  4. Cortical thinning in former professional soccer players.

    PubMed

    Koerte, Inga K; Mayinger, Michael; Muehlmann, Marc; Kaufmann, David; Lin, Alexander P; Steffinger, Denise; Fisch, Barbara; Rauchmann, Boris-Stephan; Immler, Stefanie; Karch, Susanne; Heinen, Florian R; Ertl-Wagner, Birgit; Reiser, Maximilian; Stern, Robert A; Zafonte, Ross; Shenton, Martha E

    2016-09-01

    Soccer is the most popular sport in the world. Soccer players are at high risk for repetitive subconcussive head impact when heading the ball. Whether this leads to long-term alterations of the brain's structure associated with cognitive decline remains unknown. The aim of this study was to evaluate cortical thickness in former professional soccer players using high-resolution structural MR imaging. Fifteen former male professional soccer players (mean age 49.3 [SD 5.1] years) underwent high-resolution structural 3 T MR imaging, as well as cognitive testing. Fifteen male, age-matched former professional non-contact sport athletes (mean age 49.6 [SD 6.4] years) served as controls. Group analyses of cortical thickness were performed using voxel-based statistics. Soccer players demonstrated greater cortical thinning with increasing age compared to controls in the right inferolateral-parietal, temporal, and occipital cortex. Cortical thinning was associated with lower cognitive performance as well as with estimated exposure to repetitive subconcussive head impact. Neurocognitive evaluation revealed decreased memory performance in the soccer players compared to controls. The association of cortical thinning and decreased cognitive performance, as well as exposure to repetitive subconcussive head impact, further supports the hypothesis that repetitive subconcussive head impact may play a role in early cognitive decline in soccer players. Future studies are needed to elucidate the time course of changes in cortical thickness as well as their association with impaired cognitive function and possible underlying neurodegenerative process.

  5. Choosing ℓp norms in high-dimensional spaces based on hub analysis

    PubMed Central

    Flexer, Arthur; Schnitzer, Dominik

    2015-01-01

    The hubness phenomenon is a recently discovered aspect of the curse of dimensionality. Hub objects have a small distance to an exceptionally large number of data points while anti-hubs lie far from all other data points. A closely related problem is the concentration of distances in high-dimensional spaces. Previous work has already advocated the use of fractional ℓp norms instead of the ubiquitous Euclidean norm to avoid the negative effects of distance concentration. However, which exact fractional norm to use is a largely unsolved problem. The contribution of this work is an empirical analysis of the relation of different ℓp norms and hubness. We propose an unsupervised approach for choosing an ℓp norm which minimizes hubs while simultaneously maximizing nearest neighbor classification. Our approach is evaluated on seven high-dimensional data sets and compared to three approaches that re-scale distances to avoid hubness. PMID:26640321

  6. Cortical Neural Computation by Discrete Results Hypothesis.

    PubMed

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called "Discrete Results" (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of "Discrete Results" is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel "Discrete Results" concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast-spiking (FS

  7. Cortical Neural Computation by Discrete Results Hypothesis

    PubMed Central

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called “Discrete Results” (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of “Discrete Results” is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel “Discrete Results” concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast

  8. The catheter hub disinfection cap as esophageal foreign body.

    PubMed

    Tawfik, Kareem O; Myer, Charles M; Shikary, Tasneem; Goldschneider, Kenneth R

    2015-12-01

    Disinfection caps are increasingly being used to prevent catheter-associated bloodstream infections. These devices, designed for continuous passive disinfection of catheter hubs, are typically small and often brightly colored. As such, they have the potential to become pediatric airway and esophageal foreign bodies. We report two patients who developed esophageal foreign body following ingestion of disinfection caps. Given the increasing use of these devices, it is imperative that health care providers be aware of this potential iatrogenic problem. We propose that the use of disinfection caps may not be appropriate in pediatric patients with risk factors for foreign body ingestion. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

  9. Wake center position tracking using downstream wind turbine hub loads

    NASA Astrophysics Data System (ADS)

    Cacciola, S.; Bertelè, M.; Schreiber, J.; Bottasso, C. L.

    2016-09-01

    Having an improved awareness of the flow within a wind farm is useful for power harvesting maximization, load minimization and design of wind farm layout. Local flow information at each wind turbine location can be obtained by using the response of the wind turbines, which are consequently used as distributed sensors. This paper proposes the use of hub loads to track the position of wakes within a wind farm. Simulation experiments conducted within a high-fidelity aeroservoelastic environment demonstrate the performance of the new method.

  10. Non-Shilnikov cascades of spikes and hubs in a semiconductor laser with optoelectronic feedback.

    PubMed

    Freire, Joana G; Gallas, Jason A C

    2010-09-01

    Incomplete homoclinic scenarios were recently measured in a semiconductor laser with optoelectronic feedback. We show here that such a laser contains cascades of spirals of periodic oscillations and hubs which look identical to the familiar ones observed in complete homoclinic scenarios. This means that hubs are far more general than presumed so far, being not limited by Shilnikov's theorem. Laser hubs open the possibility of measuring complex distributions of non-Shilnikov laser oscillations, and we briefly discuss how to do it.

  11. Cortical thickness abnormalities in late adolescence with online gaming addiction.

    PubMed

    Yuan, Kai; Cheng, Ping; Dong, Tao; Bi, Yanzhi; Xing, Lihong; Yu, Dahua; Zhao, Limei; Dong, Minghao; von Deneen, Karen M; Liu, Yijun; Qin, Wei; Tian, Jie

    2013-01-01

    Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18) and age-, education- and gender-matched controls (n = 18) were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC), insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction.

  12. Cortical Thickness Abnormalities in Late Adolescence with Online Gaming Addiction

    PubMed Central

    Yuan, Kai; Cheng, Ping; Dong, Tao; Bi, Yanzhi; Xing, Lihong; Yu, Dahua; Zhao, Limei; Dong, Minghao; von Deneen, Karen M.; Liu, Yijun; Qin, Wei; Tian, Jie

    2013-01-01

    Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18) and age-, education- and gender-matched controls (n = 18) were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC), insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction. PMID:23326379

  13. Development of Hub Corner Stall and Its Influence on the Performance of Axial Compressor Blade Rows

    NASA Technical Reports Server (NTRS)

    Hah, C.; Loellbach, J.

    1999-01-01

    A detailed investigation has been performed to study hub corner stall phenomena in compressor blade rows. Three-dimensional flows in a subsonic annular compressor stator and in a transonic compressor rotor have been analyzed numerically by solving the Reynolds-averaged Navier-Stokes equations. The numerical results and the existing experimental data are interrogated to understand the mechanism of compressor hub comer stall. Both the measurements and the numerical solutions for the stator indicate that a strong twister-like vortex is formed near the rear part of the blade suction surface. Low-momentum fluid inside the hub boundary layer is transported toward the suction side of the blade by this vortex. On the blade suction surface near the hub, this vortex forces fluid to move against the main flow direction and a limiting stream surface is formed near the hub. The formation of this vortex is the main mechanism of hub corner stall. When the aerodynamic loading is increased, the vortex initiates further upstream, which results in a larger corner stall region. For the transonic compressor rotor studied in this paper, the numerical solution indicates that a mild hub corner stall exists at 100 percent rotor speed. The hub corner stall, however, disappears at the reduced blade loading, which occurs at 60 percent rotor design speed. The present study demonstrates that hub comer stall is caused by a three-dimensional vortex system and that it does not seem to be correlated with a simple diffusion factor for the blade row.

  14. Design of targeted libraries against the human Chk1 kinase using PGVL Hub.

    PubMed

    Peng, Zhengwei; Hu, Qiyue

    2011-01-01

    PGVL Hub is a Pfizer internal desktop tool for chemical library and singleton design. In this chapter, we give a short introduction to PGVL Hub, the core workflow it supports, and the rich design capabilities it provides. By re-creating two legacy targeted libraries against the human checkpoint kinase 1 (Chk1) as a showcase, we illustrate how PGVL Hub could be used to help library designers carry out the steps in library design and realize design objectives such as SAR expansion and improvement in both kinase selectivity and compound aqueous solubility. Finally we share several tips about library design and usage of PGVL Hub.

  15. Neural Network Based Representation of UH-60A Pilot and Hub Accelerations

    NASA Technical Reports Server (NTRS)

    Kottapalli, Sesi

    2000-01-01

    Neural network relationships between the full-scale, experimental hub accelerations and the corresponding pilot floor vertical vibration are studied. The present physics-based, quantitative effort represents an initial systematic study on the UH-60A Black Hawk hub accelerations. The NASA/Army UH-60A Airloads Program flight test database was used. A 'maneuver-effect-factor (MEF)', derived using the roll-angle and the pitch-rate, was used. Three neural network based representation-cases were considered. The pilot floor vertical vibration was considered in the first case and the hub accelerations were separately considered in the second case. The third case considered both the hub accelerations and the pilot floor vertical vibration. Neither the advance ratio nor the gross weight alone could be used to predict the pilot floor vertical vibration. However, the advance ratio and the gross weight together could be used to predict the pilot floor vertical vibration over the entire flight envelope. The hub accelerations data were modeled and found to be of very acceptable quality. The hub accelerations alone could not be used to predict the pilot floor vertical vibration. Thus, the hub accelerations alone do not drive the pilot floor vertical vibration. However, the hub accelerations, along with either the advance ratio or the gross weight or both, could be used to satisfactorily predict the pilot floor vertical vibration. The hub accelerations are clearly a factor in determining the pilot floor vertical vibration.

  16. Gene transcription profiles associated with inter-modular hubs and connection distance in human functional magnetic resonance imaging networks

    PubMed Central

    Vértes, Petra E.; Rittman, Timothy; Whitaker, Kirstie J.; Romero-Garcia, Rafael; Váša, František; Wagstyl, Konrad; Fonagy, Peter; Dolan, Raymond J.; Jones, Peter B.; Goodyer, Ian M.

    2016-01-01

    Human functional magnetic resonance imaging (fMRI) brain networks have a complex topology comprising integrative components, e.g. long-distance inter-modular edges, that are theoretically associated with higher biological cost. Here, we estimated intra-modular degree, inter-modular degree and connection distance for each of 285 cortical nodes in multi-echo fMRI data from 38 healthy adults. We used the multivariate technique of partial least squares (PLS) to reduce the dimensionality of the relationships between these three nodal network parameters and prior microarray data on regional expression of 20 737 genes. The first PLS component defined a transcriptional profile associated with high intra-modular degree and short connection distance, whereas the second PLS component was associated with high inter-modular degree and long connection distance. Nodes in superior and lateral cortex with high inter-modular degree and long connection distance had local transcriptional profiles enriched for oxidative metabolism and mitochondria, and for genes specific to supragranular layers of human cortex. In contrast, primary and secondary sensory cortical nodes in posterior cortex with high intra-modular degree and short connection distance had transcriptional profiles enriched for RNA translation and nuclear components. We conclude that, as predicted, topologically integrative hubs, mediating long-distance connections between modules, are more costly in terms of mitochondrial glucose metabolism. This article is part of the themed issue ‘Interpreting BOLD: a dialogue between cognitive and cellular neuroscience’. PMID:27574314

  17. Cortical maturation and myelination in healthy toddlers and young children.

    PubMed

    Deoni, Sean C L; Dean, Douglas C; Remer, Justin; Dirks, Holly; O'Muircheartaigh, Jonathan

    2015-07-15

    The maturation of cortical structures, and the establishment of their connectivity, are critical neurodevelopmental processes that support and enable cognitive and behavioral functioning. Measures of cortical development, including thickness, curvature, and gyrification have been extensively studied in older children, adolescents, and adults, revealing regional associations with cognitive performance, and alterations with disease or pathology. In addition to these gross morphometric measures, increased attention has recently focused on quantifying more specific indices of cortical structure, in particular intracortical myelination, and their relationship to cognitive skills, including IQ, executive functioning, and language performance. Here we analyze the progression of cortical myelination across early childhood, from 1 to 6 years of age, in vivo for the first time. Using two quantitative imaging techniques, namely T1 relaxation time and myelin water fraction (MWF) imaging, we characterize myelination throughout the cortex, examine developmental trends, and investigate hemispheric and gender-based differences. We present a pattern of cortical myelination that broadly mirrors established histological timelines, with somatosensory, motor and visual cortices myelinating by 1 year of age; and frontal and temporal cortices exhibiting more protracted myelination. Developmental trajectories, defined by logarithmic functions (increasing for MWF, decreasing for T1), were characterized for each of 68 cortical regions. Comparisons of trajectories between hemispheres and gender revealed no significant differences. Results illustrate the ability to quantitatively map cortical myelination throughout early neurodevelopment, and may provide an important new tool for investigating typical and atypical development.

  18. Cortical maturation and myelination in healthy toddlers and young children

    PubMed Central

    Deoni, Sean C.L.; Dean, Douglas C.; Remer, Justin; Dirks, Holly; O’Muircheartaigh, Jonathan

    2015-01-01

    The maturation of cortical structures, and the establishment of their connectivity, are critical neurodevelopmental processes that support and enable cognitive and behavioral functioning. Measures of cortical development, including thickness, curvature, and gyrification have been extensively studied in older children, adolescents, and adults, revealing regional associations with cognitive performance, and alterations with disease or pathology. In addition to these gross morphometric measures, increased attention has recently focused on quantifying more specific indices of cortical structure, in particular intracortical myelination, and their relationship to cognitive skills, including IQ, executive functioning, and language performance. Here we analyze the progression of cortical myelination across early childhood, from 1 to 6 years of age, in vivo for the first time. Using two quantitative imaging techniques, namely T1 relaxation time and myelin water fraction (MWF) imaging, we characterize myelination throughout the cortex, examine developmental trends, and investigate hemispheric and gender-based differences. We present a pattern of cortical myelination that broadly mirrors established histological timelines, with somatosensory, motor and visual cortices myelinating by 1 year of age; and frontal and temporal cortices exhibiting more protracted myelination. Developmental trajectories, defined by logarithmic functions (increasing for MWF, decreasing for T1), were characterized for each of 68 cortical regions. Comparisons of trajectories between hemispheres and gender revealed no significant differences. Results illustrate the ability to quantitatively map cortical myelination throughout early neurodevelopment, and may provide an important new tool for investigating typical and atypical development. PMID:25944614

  19. Design and Development of an Integrated Workstation Automation Hub

    SciTech Connect

    Weber, Andrew; Ghatikar, Girish; Sartor, Dale; Lanzisera, Steven

    2015-03-30

    Miscellaneous Electronic Loads (MELs) account for one third of all electricity consumption in U.S. commercial buildings, and are drivers for a significant energy use in India. Many of the MEL-specific plug-load devices are concentrated at workstations in offices. The use of intelligence, and integrated controls and communications at the workstation for an Office Automation Hub – offers the opportunity to improve both energy efficiency and occupant comfort, along with services for Smart Grid operations. Software and hardware solutions are available from a wide array of vendors for the different components, but an integrated system with interoperable communications is yet to be developed and deployed. In this study, we propose system- and component-level specifications for the Office Automation Hub, their functions, and a prioritized list for the design of a proof-of-concept system. Leveraging the strength of both the U.S. and India technology sectors, this specification serves as a guide for researchers and industry in both countries to support the development, testing, and evaluation of a prototype product. Further evaluation of such integrated technologies for performance and cost is necessary to identify the potential to reduce energy consumptions in MELs and to improve occupant comfort.

  20. Disinfection of Needleless Connector Hubs: Clinical Evidence Systematic Review

    PubMed Central

    Moureau, Nancy L.

    2015-01-01

    Background. Needleless connectors (NC) are used on virtually all intravascular devices, providing an easy access point for infusion connection. Colonization of NC is considered the cause of 50% of postinsertion catheter-related infections. Breaks in aseptic technique, from failure to disinfect, result in contamination and subsequent biofilm formation within NC and catheters increasing the potential for infection of central and peripheral catheters. Methods. This systematic review evaluated 140 studies and 34 abstracts on NC disinfection practices, the impact of hub contamination on infection, and measures of education and compliance. Results. The greatest risk for contamination of the catheter after insertion is the NC with 33–45% contaminated, and compliance with disinfection as low as 10%. The optimal technique or disinfection time has not been identified, although scrubbing with 70% alcohol for 5–60 seconds is recommended. Studies have reported statistically significant results in infection reduction when passive alcohol disinfection caps are used (48–86% reduction). Clinical Implications. It is critical for healthcare facilities and clinicians to take responsibility for compliance with basic principles of asepsis compliance, to involve frontline staff in strategies, to facilitate education that promotes understanding of the consequences of failure, and to comply with the standard of care for hub disinfection. PMID:26075093

  1. In-wheel hub SRM simulation and analysis

    NASA Astrophysics Data System (ADS)

    Sager, Milton W., III

    Is it feasible to replace the conventional gasoline engine and subsequent drive system in a motorcycle with an electric switched reluctance motor (SRM) by placing the SRM inside the rear wheel, thereby removing the need for things such as a clutch, chain, transmission, gears and sprockets? The goal of this thesis is to study the theoretical aspect of prototyping and analyzing an in-wheel electric hub motor to replace the standard gasoline engine traditionally found on motorcycles. With the recent push for clean energy, electric vehicles are becoming more common. All currently produced electric motorcycles use conventional, prefabricated electric motors connected to the traditional sprocket and chain design. This greatly restricts the efficiency and range of these motorcycles. My design stands apart by turning the rear wheel into a SRM which uses electromagnets around a non-magnetic core to convert electrical energy into mechanical force driving the rear wheel. To my knowledge, there is currently no motorcycle designed with an in-wheel hub SRM. A three-phase SRM and a five-phase SRM will be simulated and analyzed using MATLAB with Simulink. Factors such as friction, weight, power, etc. will be taken into account in order to create a realistic simulation as if it were inside the rear wheel of a motorcycle. Since time and finances will not allow for a full scale build, a scaled model three-phase SRM will be attempted for demonstration purposes.

  2. PGD: a pangolin genome hub for the research community.

    PubMed

    Tan, Tze King; Tan, Ka Yun; Hari, Ranjeev; Mohamed Yusoff, Aini; Wong, Guat Jah; Siow, Cheuk Chuen; Mutha, Naresh V R; Rayko, Mike; Komissarov, Aleksey; Dobrynin, Pavel; Krasheninnikova, Ksenia; Tamazian, Gaik; Paterson, Ian C; Warren, Wesley C; Johnson, Warren E; O'Brien, Stephen J; Choo, Siew Woh

    2016-01-01

    Pangolins (order Pholidota) are the only mammals covered by scales. We have recently sequenced and analyzed the genomes of two critically endangered Asian pangolin species, namely the Malayan pangolin (Manis javanica) and the Chinese pangolin (Manis pentadactyla). These complete genome sequences will serve as reference sequences for future research to address issues of species conservation and to advance knowledge in mammalian biology and evolution. To further facilitate the global research effort in pangolin biology, we developed the Pangolin Genome Database (PGD), as a future hub for hosting pangolin genomic and transcriptomic data and annotations, and with useful analysis tools for the research community. Currently, the PGD provides the reference pangolin genome and transcriptome data, gene sequences and functional information, expressed transcripts, pseudogenes, genomic variations, organ-specific expression data and other useful annotations. We anticipate that the PGD will be an invaluable platform for researchers who are interested in pangolin and mammalian research. We will continue updating this hub by including more data, annotation and analysis tools particularly from our research consortium.Database URL: http://pangolin-genome.um.edu.my.

  3. Managing the cellular redox hub in photosynthetic organisms.

    PubMed

    Foyer, Christine H; Noctor, Graham

    2012-02-01

    Light-driven redox chemistry is a powerful source of redox signals that has a decisive input into transcriptional control within the cell nucleus. Like photosynthetic electron transport pathways, the respiratory electron transport chain exerts a profound control over gene function, in order to balance energy (reductant and ATP) supply with demand, while preventing excessive over-reduction or over-oxidation that would be adversely affect metabolism. Photosynthetic and respiratory redox chemistries are not merely housekeeping processes but they exert a controlling influence over every aspect of plant biology, participating in the control of gene transcription and translation, post-translational modifications and the regulation of assimilatory reactions, assimilate partitioning and export. The number of processes influenced by redox controls and signals continues to increase as do the components that are recognized participants in the associated signalling pathways. A step change in our understanding of the overall importance of the cellular redox hub to plant cells has occurred in recent years as the complexity of the management of the cellular redox hub in relation to metabolic triggers and environmental cues has been elucidated. This special issue describes aspects of redox regulation and signalling at the cutting edge of current research in this dynamic and rapidly expanding field. © 2011 Blackwell Publishing Ltd.

  4. PGD: a pangolin genome hub for the research community

    PubMed Central

    Tan, Tze King; Tan, Ka Yun; Hari, Ranjeev; Mohamed Yusoff, Aini; Wong, Guat Jah; Siow, Cheuk Chuen; Mutha, Naresh V.R.; Rayko, Mike; Komissarov, Aleksey; Dobrynin, Pavel; Krasheninnikova, Ksenia; Tamazian, Gaik; Paterson, Ian C.; Warren, Wesley C.; Johnson, Warren E.; O'Brien, Stephen J.; Choo, Siew Woh

    2016-01-01

    Pangolins (order Pholidota) are the only mammals covered by scales. We have recently sequenced and analyzed the genomes of two critically endangered Asian pangolin species, namely the Malayan pangolin (Manis javanica) and the Chinese pangolin (Manis pentadactyla). These complete genome sequences will serve as reference sequences for future research to address issues of species conservation and to advance knowledge in mammalian biology and evolution. To further facilitate the global research effort in pangolin biology, we developed the Pangolin Genome Database (PGD), as a future hub for hosting pangolin genomic and transcriptomic data and annotations, and with useful analysis tools for the research community. Currently, the PGD provides the reference pangolin genome and transcriptome data, gene sequences and functional information, expressed transcripts, pseudogenes, genomic variations, organ-specific expression data and other useful annotations. We anticipate that the PGD will be an invaluable platform for researchers who are interested in pangolin and mammalian research. We will continue updating this hub by including more data, annotation and analysis tools particularly from our research consortium. Database URL: http://pangolin-genome.um.edu.my PMID:27616775

  5. Sharing the World's Advanced Rheology Knowledge through Rheo-Hub

    NASA Astrophysics Data System (ADS)

    Winter, H. Henning

    2008-07-01

    Recent advances in rheometer design and rheology theory have led to an abundance of rheological information, both experimental and theoretical. In response to this wonderful opportunity, many of the world's leading rheologists began to share their expert software codes with the wider community of materials researchers and practitioners. This became possible through "Rheo-Hub", a central computer platform from which the user interrogates rheological expert codes ("engines") and rheological data by comparing, merging, and funneling these into further interrogations and explorations. In this virtual environment, results are returned to the computer screen as visuals so that the visual intelligence of the user gets involved in the cognition process. Rheological explorations may be repeated in different ways (using different expert codes for answering the same research question) and viewed from different graphical viewpoints. This creates the multi-scale and multi-expertise workspace that is needed to support quantitative rheological explorations and to prepare for discovery. The virtual environment technology will be presented and examples will be shown. Rheo-Hub's strengths are data analysis, integration of experimental results with theoretically predicted rheology, visuals for communicating results, and introduction of a rheological data standard.

  6. Convergence and divergence are mostly reciprocated properties of the connections in the network of cortical areas.

    PubMed

    Négyessy, László; Nepusz, Tamás; Zalányi, László; Bazsó, Fülöp

    2008-10-22

    Cognition is based on the integrated functioning of hierarchically organized cortical processing streams in a manner yet to be clarified. Because integration fundamentally depends on convergence and the complementary notion of divergence of the neuronal connections, we analysed integration by measuring the degree of convergence/divergence through the connections in the network of cortical areas. By introducing a new index, we explored the complementary convergent and divergent nature of connectional reciprocity and delineated the backward and forward cortical sub-networks for the first time. Integrative properties of the areas defined by the degree of convergence/divergence through their afferents and efferents exhibited distinctive characteristics at different levels of the cortical hierarchy. Areas previously identified as hubs exhibit information bottleneck properties. Cortical networks largely deviate from random graphs where convergence and divergence are balanced at low reciprocity level. In the cortex, which is dominated by reciprocal connections, balance appears only by further increasing the number of reciprocal connections. The results point to the decisive role of the optimal number and placement of reciprocal connections in large-scale cortical integration. Our findings also facilitate understanding of the functional interactions between the cortical areas and the information flow or its equivalents in highly recurrent natural and artificial networks.

  7. Cortical Polarity of the RING Protein PAR-2 Is Maintained by Exchange Rate Kinetics at the Cortical-Cytoplasmic Boundary.

    PubMed

    Arata, Yukinobu; Hiroshima, Michio; Pack, Chan-Gi; Ramanujam, Ravikrishna; Motegi, Fumio; Nakazato, Kenichi; Shindo, Yuki; Wiseman, Paul W; Sawa, Hitoshi; Kobayashi, Tetsuya J; Brandão, Hugo B; Shibata, Tatsuo; Sako, Yasushi

    2016-08-23

    Cell polarity arises through the spatial segregation of polarity regulators. PAR proteins are polarity regulators that localize asymmetrically to two opposing cortical domains. However, it is unclear how the spatially segregated PAR proteins interact to maintain their mutually exclusive partitioning. Here, single-molecule detection analysis in Caenorhabditis elegans embryos reveals that cortical PAR-2 diffuses only short distances, and, as a result, most PAR-2 molecules associate and dissociate from the cortex without crossing into the opposing domain. Our results show that cortical PAR-2 asymmetry is maintained by the local exchange reactions that occur at the cortical-cytoplasmic boundary. Additionally, we demonstrate that local exchange reactions are sufficient to maintain cortical asymmetry in a parameter-free mathematical model. These findings suggest that anterior and posterior PAR proteins primarily interact through the cytoplasmic pool and not via cortical diffusion.

  8. Discovering Cortical Folding Patterns in Neonatal Cortical Surfaces Using Large-Scale Dataset

    PubMed Central

    Meng, Yu; Li, Gang; Wang, Li; Lin, Weili; Gilmore, John H.

    2017-01-01

    The cortical folding of the human brain is highly complex and variable across individuals. Mining the major patterns of cortical folding from modern large-scale neuroimaging datasets is of great importance in advancing techniques for neuroimaging analysis and understanding the inter-individual variations of cortical folding and its relationship with cognitive function and disorders. As the primary cortical folding is genetically influenced and has been established at term birth, neonates with the minimal exposure to the complicated postnatal environmental influence are the ideal candidates for understanding the major patterns of cortical folding. In this paper, for the first time, we propose a novel method for discovering the major patterns of cortical folding in a large-scale dataset of neonatal brain MR images (N = 677). In our method, first, cortical folding is characterized by the distribution of sulcal pits, which are the locally deepest points in cortical sulci. Because deep sulcal pits are genetically related, relatively consistent across individuals, and also stable during brain development, they are well suitable for representing and characterizing cortical folding. Then, the similarities between sulcal pit distributions of any two subjects are measured from spatial, geometrical, and topological points of view. Next, these different measurements are adaptively fused together using a similarity network fusion technique, to preserve their common information and also catch their complementary information. Finally, leveraging the fused similarity measurements, a hierarchical affinity propagation algorithm is used to group similar sulcal folding patterns together. The proposed method has been applied to 677 neonatal brains (the largest neonatal dataset to our knowledge) in the central sulcus, superior temporal sulcus, and cingulate sulcus, and revealed multiple distinct and meaningful folding patterns in each region. PMID:28229131

  9. Cortically projecting basal forebrain parvalbumin neurons regulate cortical gamma band oscillations.

    PubMed

    Kim, Tae; Thankachan, Stephen; McKenna, James T; McNally, James M; Yang, Chun; Choi, Jee Hyun; Chen, Lichao; Kocsis, Bernat; Deisseroth, Karl; Strecker, Robert E; Basheer, Radhika; Brown, Ritchie E; McCarley, Robert W

    2015-03-17

    Cortical gamma band oscillations (GBO, 30-80 Hz, typically ∼40 Hz) are involved in higher cognitive functions such as feature binding, attention, and working memory. GBO abnormalities are a feature of several neuropsychiatric disorders associated with dysfunction of cortical fast-spiking interneurons containing the calcium-binding protein parvalbumin (PV). GBO vary according to the state of arousal, are modulated by attention, and are correlated with conscious awareness. However, the subcortical cell types underlying the state-dependent control of GBO are not well understood. Here we tested the role of one cell type in the wakefulness-promoting basal forebrain (BF) region, cortically projecting GABAergic neurons containing PV, whose virally transduced fibers we found apposed cortical PV interneurons involved in generating GBO. Optogenetic stimulation of BF PV neurons in mice preferentially increased cortical GBO power by entraining a cortical oscillator with a resonant frequency of ∼40 Hz, as revealed by analysis of both rhythmic and nonrhythmic BF PV stimulation. Selective saporin lesions of BF cholinergic neurons did not alter the enhancement of cortical GBO power induced by BF PV stimulation. Importantly, bilateral optogenetic inhibition of BF PV neurons decreased the power of the 40-Hz auditory steady-state response, a read-out of the ability of the cortex to generate GBO used in clinical studies. Our results are surprising and novel in indicating that this presumptively inhibitory BF PV input controls cortical GBO, likely by synchronizing the activity of cortical PV interneurons. BF PV neurons may represent a previously unidentified therapeutic target to treat disorders involving abnormal GBO, such as schizophrenia.

  10. Predicting highly-connected hubs in protein interaction networks by QSAR and biological data descriptors

    PubMed Central

    Hsing, Michael; Byler, Kendall; Cherkasov, Artem

    2009-01-01

    Hub proteins (those engaged in most physical interactions in a protein interaction network (PIN) have recently gained much research interest due to their essential role in mediating cellular processes and their potential therapeutic value. It is straightforward to identify hubs if the underlying PIN is experimentally determined; however, theoretical hub prediction remains a very challenging task, as physicochemical properties that differentiate hubs from less connected proteins remain mostly uncharacterized. To adequately distinguish hubs from non-hub proteins we have utilized over 1300 protein descriptors, some of which represent QSAR (quantitative structure-activity relationship) parameters, and some reflect sequence-derived characteristics of proteins including domain composition and functional annotations. Those protein descriptors, together with available protein interaction data have been processed by a machine learning method (boosting trees) and resulted in the development of hub classifiers that are capable of predicting highly interacting proteins for four model organisms: Escherichia coli, Saccharomyces cerevisiae, Drosophila melanogaster and Homo sapiens. More importantly, through the analyses of the most relevant protein descriptors, we are able to demonstrate that hub proteins not only share certain common physicochemical and structural characteristics that make them different from non-hub counterparts, but they also exhibit species-specific characteristics that should be taken into account when analyzing different PINs. The developed prediction models can be used for determining highly interacting proteins in the four studied species to assist future proteomics experiments and PIN analyses. Availability The source code and executable program of the hub classifier are available for download at: http://www.cnbi2.ca/hub-analysis/ PMID:20198194

  11. Mechanisms of Hierarchical Cortical Maturation

    PubMed Central

    Chomiak, Taylor; Hu, Bin

    2017-01-01

    Cortical information processing is structurally and functionally organized into hierarchical pathways, with primary sensory cortical regions providing modality specific information and associative cortical regions playing a more integrative role. Historically, there has been debate as to whether primary cortical regions mature earlier than associative cortical regions, or whether both primary and associative cortical regions mature simultaneously. Identifying whether primary and associative cortical regions mature hierarchically or simultaneously will not only deepen our understanding of the mechanisms that regulate brain maturation, but it will also provide fundamental insight into aspects of adolescent behavior, learning, neurodevelopmental disorders and computational models of neural processing. This mini-review article summarizes the current evidence supporting the sequential and hierarchical nature of cortical maturation, and then proposes a new cellular model underlying this process. Finally, unresolved issues associated with hierarchical cortical maturation are also addressed. PMID:28959187

  12. The Association of Aging with White Matter Integrity and Functional Connectivity Hubs

    PubMed Central

    Yang, Albert C.; Tsai, Shih-Jen; Liu, Mu-En; Huang, Chu-Chung; Lin, Ching-Po

    2016-01-01

    Normal aging is associated with reduced cerebral structural integrity and altered functional brain activity, yet the association of aging with the relationship between structural and functional brain changes remains unclear. Using combined diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) modalities, we hypothesized that aging-related changes in white matter integrity (i.e., fractional anisotropy) was associated with the short- or long-range functional connectivity density (FCD) in hub regions. We tested this hypothesis by using a healthy aging cohort comprised of 140 younger adults aged 20–39 years and 109 older adults aged 60–79 years. Compared with the younger group, older adults exhibited widespread reductions in white matter integrity with selective preservation in brain stem tracts and the cingulum connected to the hippocampus and cingulate cortex, whereas FCD mapping in older adults showed a reduced FCD in the visual, somatosensory, and motor functional networks and an increased FCD in the default mode network. The older adults exhibited significantly increased short- or long-range FCD in functional hubs of the precuneus, posterior, and middle cingulate, and thalamus, hippocampus, fusiform, and inferior temporal cortex. Furthermore, DTI-fMRI relationship were predominantly identified in older adults in whom short- and long-range FCD in the left precuneus was negatively correlated to structural integrity of adjacent and nonadjacent white matter tracts, respectively. We also found that long-range FCD in the left precuneus was positively correlated to cognitive function. These results support the compensatory hypothesis of neurocognitive aging theory and reveal the DTI-fMRI relationship associated with normal aging. PMID:27378915

  13. Cortical microtubules in sweet clover columella cells developed in microgravity

    NASA Technical Reports Server (NTRS)

    Hilaire, E.; Paulsen, A. Q.; Brown, C. S.; Guikema, J. A.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    Electron micrographs of columella cells from sweet clover seedlings grown and fixed in microgravity revealed longitudinal and cross sectioned cortical microtubules. This is the first report demonstrating the presence and stability of this network in plants in microgravity.

  14. Decision by division: making cortical maps

    PubMed Central

    Rakic, Pasko; Ayoub, Albert E.; Breunig, Joshua J.; Dominguez, Martin H.

    2013-01-01

    In the past three decades, mounting evidence has revealed that specification of the basic cortical neuronal classes starts at the time of their final mitotic divisions in the embryonic proliferative zones. This early cell determination continues during the migration of the newborn neurons across the widening cerebral wall, and it is in the cortical plate that they attain their final positions and establish species-specific cytoarchitectonic areas. Here, the development and evolutionary expansion of the neocortex is viewed in the context of the radial unit and protomap hypotheses. A broad spectrum of findings gave insight into the pathogenesis of cortical malformations and the biological bases for the evolution of the modern human neocortex. We examine the history and evidence behind the concept of early specification of neurons and provide the latest compendium of genes and signaling molecules involved in neuronal fate determination and specification. PMID:19380167

  15. Co-Construction, Infrastructure, and Purpose: Influences on Implementation of Hub-Outlet School Reform

    ERIC Educational Resources Information Center

    Lenhoff, Sarah Winchell

    2013-01-01

    This dissertation is a collection of three interrelated chapters that explore unique dimensions of hub-outlet school reform. This type of school reform, in which a central hub organization designs a model for instructional improvement meant to be implemented with fidelity across unique outlet school sites, has gained credibility in the crowded…

  16. Regional services in a research context: USDA Climate Hubs in the USDA Agricultural Research Service

    USDA-ARS?s Scientific Manuscript database

    Ten USDA Climate Hubs were created in 2014 to develop and deliver science-based, region-specific information and technologies to better enable agricultural decision-making and management. Of these ten Hubs, half are administered by USDA’s Agricultural Research Service (ARS), an agency with historica...

  17. 14 CFR 158.30 - PFC Authorization at Non-Hub Airports.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false PFC Authorization at Non-Hub Airports. 158... (CONTINUED) AIRPORTS PASSENGER FACILITY CHARGES (PFC'S) Application and Approval § 158.30 PFC Authorization at Non-Hub Airports. (a) General. This section specifies the procedures a public agency controlling a...

  18. 14 CFR 158.30 - PFC Authorization at Non-Hub Airports.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false PFC Authorization at Non-Hub Airports. 158... (CONTINUED) AIRPORTS PASSENGER FACILITY CHARGES (PFC'S) Application and Approval § 158.30 PFC Authorization at Non-Hub Airports. (a) General. This section specifies the procedures a public agency controlling a...

  19. 14 CFR 158.30 - PFC Authorization at Non-Hub Airports.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false PFC Authorization at Non-Hub Airports. 158... (CONTINUED) AIRPORTS PASSENGER FACILITY CHARGES (PFC'S) Application and Approval § 158.30 PFC Authorization at Non-Hub Airports. (a) General. This section specifies the procedures a public agency controlling a...

  20. 76 FR 18753 - Jefferson Island Storage & Hub, L.L.C.; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-05

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Jefferson Island Storage & Hub, L.L.C.; Notice of Filing Take notice that on March 28, 2011, Jefferson Island Storage & Hub, L.L.C. (Jefferson Island) submitted a revised...

  1. 78 FR 20314 - Jefferson Island Storage & Hub, L.L.C.; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Jefferson Island Storage & Hub, L.L.C.; Notice of Filing Take notice that on March 28, 2013, Jefferson Island Storage & Hub, L.L.C. filed to revise its Statement of...

  2. Stress analysis of 27% scale model of AH-64 main rotor hub

    NASA Technical Reports Server (NTRS)

    Hodges, R. V.

    1985-01-01

    Stress analysis of an AH-64 27% scale model rotor hub was performed. Component loads and stresses were calculated based upon blade root loads and motions. The static and fatigue analysis indicates positive margins of safety in all components checked. Using the format developed here, the hub can be stress checked for future application.

  3. 76 FR 53426 - Moss Bluff Hub, LLC; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Baseline Filing Take notice that on August 17, 2011, Moss Bluff Hub, LLC submitted a revised Statement of Operating Conditions, that governs...

  4. 75 FR 33799 - Moss Bluff Hub, LLC; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Baseline Filing June 8, 2010. Take notice that on June 1, 2010, Moss Bluff Hub, LLC submitted a baseline filing of its Statement of General...

  5. The Complexities and Challenges of Regional Education Hubs: Focus on Malaysia

    ERIC Educational Resources Information Center

    Knight, Jane; Morshidi, Sirat

    2011-01-01

    The race to establish regional education hubs is a recent development in cross-border higher education. This article briefly examines the rationales and strategies used by three countries in the Middle East and three in South East Asia which are working towards positioning themselves as regional education hubs. The different approaches and…

  6. USDA Northeast Climate Hub: delivering science-based knowledge and practical information

    USDA-ARS?s Scientific Manuscript database

    The USDA Northeast Climate Hub is one of seven regional hubs created in February 2014 and is a partnership among USDA and other federal agencies, universities, Tribal governments, and state and private organizations within the northeast region from Maine to West Virginia. The USDA Northeast Climate ...

  7. MR appearance of distal femoral cortical irregularity (cortical desmoid)

    SciTech Connect

    Suh, Jin-Suck; Cho, Jae-Hyun; Shin, Kyoo-Ho

    1996-03-01

    Our goal was to describe the MR appearance of distal femoral cortical irregularity (DFCI). With plain radiographs and MR images of 100 knees, the presence of DFCIs was determined, and the shapes of DFCIs were classified into three subgroups: concave, convex, and divergent cortical shapes. Radiographic and MR shapes of DFCIs were compared. DFCIs were shown in various shapes on both the radiographs and the MR images. Forty-four DFCIs were found both on radiograph and by MR image. An additional 14 DFCIs were identifiable only on MR images. However, the majority of DFCIs showed an association between radiographic and MR shapes. MRI revealed that all 58 DFCIs were located at the attachment site of the media gastrocnemius muscle. DFCIs were enhanced in three of the four patients who underwent postcontrast MR study. A good understanding of radiographic and MR findings of the DFCI may be of great help in the differential diagnosis of distal femoral lesions. 16 refs., 6 figs., 1 tab.

  8. Cortical Gyrification Patterns Associated with Trait Anxiety

    PubMed Central

    Miskovich, Tara A.; Pedersen, Walker S.; Belleau, Emily L.; Shollenbarger, Skyler; Lisdahl, Krista M.; Larson, Christine L.

    2016-01-01

    Dispositional anxiety is a stable personality trait that is a key risk factor for internalizing disorders, and understanding the neural correlates of trait anxiety may help us better understand the development of these disorders. Abnormal cortical folding is thought to reflect differences in cortical connectivity occurring during brain development. Therefore, assessing gyrification may advance understanding of cortical development and organization associated with trait anxiety. Previous literature has revealed structural abnormalities in trait anxiety and related disorders, but no study to our knowledge has examined gyrification in trait anxiety. We utilized a relatively novel measure, the local gyrification index (LGI), to explore differences in gyrification as a function of trait anxiety. We obtained structural MRI scans using a 3T magnetic resonance scanner on 113 young adults. Results indicated a negative correlation between trait anxiety and LGI in the left superior parietal cortex, specifically the precuneus, reflecting less cortical complexity among those high on trait anxiety. Our findings suggest that aberrations in cortical gyrification in a key region of the default mode network is a correlate of trait anxiety and may reflect disrupted local parietal connectivity. PMID:26872350

  9. Symmetry breaking in reconstituted actin cortices

    PubMed Central

    Abu Shah, Enas; Keren, Kinneret

    2014-01-01

    The actin cortex plays a pivotal role in cell division, in generating and maintaining cell polarity and in motility. In all these contexts, the cortical network has to break symmetry to generate polar cytoskeletal dynamics. Despite extensive research, the mechanisms responsible for regulating cortical dynamics in vivo and inducing symmetry breaking are still unclear. Here we introduce a reconstituted system that self-organizes into dynamic actin cortices at the inner interface of water-in-oil emulsions. This artificial system undergoes spontaneous symmetry breaking, driven by myosin-induced cortical actin flows, which appears remarkably similar to the initial polarization of the embryo in many species. Our in vitro model system recapitulates the rich dynamics of actin cortices in vivo, revealing the basic biophysical and biochemical requirements for cortex formation and symmetry breaking. Moreover, this synthetic system paves the way for further exploration of artificial cells towards the realization of minimal model systems that can move and divide. DOI: http://dx.doi.org/10.7554/eLife.01433.001 PMID:24843007

  10. Mapping cortical mesoscopic networks of single spiking cortical or sub-cortical neurons.

    PubMed

    Xiao, Dongsheng; Vanni, Matthieu P; Mitelut, Catalin C; Chan, Allen W; LeDue, Jeffrey M; Xie, Yicheng; Chen, Andrew Cn; Swindale, Nicholas V; Murphy, Timothy H

    2017-02-04

    Understanding the basis of brain function requires knowledge of cortical operations over wide-spatial scales, but also within the context of single neurons. In vivo, wide-field GCaMP imaging and sub-cortical/cortical cellular electrophysiology were used in mice to investigate relationships between spontaneous single neuron spiking and mesoscopic cortical activity. We make use of a rich set of cortical activity motifs that are present in spontaneous activity in anesthetized and awake animals. A mesoscale spike-triggered averaging procedure allowed the identification of motifs that are preferentially linked to individual spiking neurons by employing genetically targeted indicators of neuronal activity. Thalamic neurons predicted and reported specific cycles of wide-scale cortical inhibition/excitation. In contrast, spike-triggered maps derived from single cortical neurons yielded spatio-temporal maps expected for regional cortical consensus function. This approach can define network relationships between any point source of neuronal spiking and mesoscale cortical maps.

  11. Hub-filament System in IRAS 05480+2545: Young Stellar Cluster and 6.7 GHz Methanol Maser

    NASA Astrophysics Data System (ADS)

    Dewangan, L. K.; Ojha, D. K.; Baug, T.

    2017-07-01

    To probe the star formation (SF) process, we present a multi-wavelength study of IRAS 05480+2545 (hereafter I05480+2545). Analysis of Herschel data reveals a massive clump (M clump ˜ 1875 {M}⊙ ; peak N(H2) ˜ 4.8 × 1022 cm-2 A V ˜ 51 mag) containing the 6.7 GHz methanol maser and I05480+2545, which is also depicted in a temperature range of 18-26 K. Several noticeable parsec-scale filaments are detected in the Herschel 250 μm image and seem to be radially directed to the massive clump. It resembles more of a “hub-filament” system. Deeply embedded young stellar objects (YSOs) have been identified using the 1-5 μm photometric data, and a significant fraction of YSOs and their clustering are spatially found toward the massive clump, revealing the intense SF activities. An infrared counterpart (IRc) of the maser is investigated in the Spitzer 3.6-4.5 μm images. The IRc does not appear as a point-like source and is most likely associated with the molecular outflow. Based on the 1.4 GHz and Hα continuum images, the ionized emission is absent toward the IRc, indicating that the massive clump harbors an early phase of a massive protostar before the onset of an ultracompact H ii region. Together, the I05480+2545 is embedded in a very similar “hub-filament” system to those seen in the Rosette Molecular Cloud. The outcome of the present work indicates the role of filaments in the formation of the massive star-forming clump and cluster of YSOs, which might help channel material to the central hub configuration and the clump/core.

  12. Effective spectral dimension of hub in scale-free networks

    NASA Astrophysics Data System (ADS)

    Hwang, Sungmin; Lee, Deok-Sun; Kahng, Byungnam

    2012-02-01

    Exploring the World Wide Web has become one of the key issues in information science, specifically in context of its application to the PageRank-like algorithms used in search engine. The random walk approach has been employed to study such a problem. The probability of the return to the origin (RTO) of random walks is inversely related to how information can be accessed during random surfing. We find analytically that the RTO probability for a given starting node shows a crossover from a slow to a fast decay behavior with time and the crossover time increases with the degree of the starting node. Furthermore, the RTO probability is almost constant in the early-time regime as the degree exponent approaches two. This result indicates that a random surfer can be effectively trapped at the hub and supports the necessity of the random jump strategy empirically used in the Google's search engine.

  13. Paneth cells: the hub for sensing and regulating intestinal flora.

    PubMed

    Zhang, Zheng; Liu, Zhihua

    2016-05-01

    The complex interplay between symbiotic bacteria and host immunity plays a key role in shaping intestinal homeostasis and maintaining host health. Paneth cells, as one of the major producers of antimicrobial peptides in the intestine under steady-state conditions, play a vital role in regulating intestinal flora. Many studies on inflammatory bowel disease (IBD)-associated genes have put Paneth cells at the center of IBD pathogenesis. In this perspective, we focus on mechanistic studies of different cellular processes in Paneth cells that are regulated by various IBD-associated susceptibility genes, and we discuss the hypothesis that Paneth cells function as the central hub for sensing and regulating intestinal flora in the maintenance of intestinal homeostasis.

  14. Arrestins as regulatory hubs in cancer signalling pathways.

    PubMed

    Enslen, Hervé; Lima-Fernandes, Evelyne; Scott, Mark G H

    2014-01-01

    Non-visual arrestins were initially appreciated for the roles they play in the negative regulation of G protein-coupled receptors through the processes of desensitisation and endocytosis. The arrestins are also now known as protein scaffolding platforms that act downstream of multiple types of receptors, ensuring relevant transmission of information for an appropriate cellular response. They function as regulatory hubs in several important signalling pathways that are often dysregulated in human cancers. Interestingly, several recent studies have documented changes in expression and localisation of arrestins that occur during cancer progression and that correlate with clinical outcome. Here, we discuss these advances and how changes in expression/localisation may affect functional outputs of arrestins in cancer biology.

  15. TYCTWD Program and Hub Registration Open through May 16 | Poster

    Cancer.gov

    “How long until the next Take Your Child to Work Day?” is a question Randy Johnson hears multiple times throughout the year from his five children, who range in age from 7 to 14. “It’s really fun and you get to experiment with things,” said Johnson’s 10-year-old daughter, Mary Joy. Be a part of the annual event that kids look forward to all year long and help foster the next generation of scientists. The 20th annual Take Your Child to Work Day (TYCTWD) at NCI at Frederick is coming up on June 29, and registration for hub and program activities ends May 16.

  16. Collective versus hub activation of epidemic phases on networks

    NASA Astrophysics Data System (ADS)

    Ferreira, Silvio C.; Sander, Renan S.; Pastor-Satorras, Romualdo

    2016-03-01

    We consider a general criterion to discern the nature of the threshold in epidemic models on scale-free (SF) networks. Comparing the epidemic lifespan of the nodes with largest degrees with the infection time between them, we propose a general dual scenario, in which the epidemic transition is either ruled by a hub activation process, leading to a null threshold in the thermodynamic limit, or given by a collective activation process, corresponding to a standard phase transition with a finite threshold. We validate the proposed criterion applying it to different epidemic models, with waning immunity or heterogeneous infection rates in both synthetic and real SF networks. In particular, a waning immunity, irrespective of its strength, leads to collective activation with finite threshold in scale-free networks with large degree exponent, at odds with canonical theoretical approaches.

  17. TYCTWD Program and Hub Registration Open through May 16 | Poster

    Cancer.gov

    “How long until the next Take Your Child to Work Day?” is a question Randy Johnson hears multiple times throughout the year from his five children, who range in age from 7 to 14. “It’s really fun and you get to experiment with things,” said Johnson’s 10-year-old daughter, Mary Joy. Be a part of the annual event that kids look forward to all year long and help foster the next generation of scientists. The 20th annual Take Your Child to Work Day (TYCTWD) at NCI at Frederick is coming up on June 29, and registration for hub and program activities ends May 16.

  18. Enhancers as information integration hubs in development: lessons from genomics

    PubMed Central

    Buecker, Christa; Wysocka, Joanna

    2016-01-01

    Transcriptional enhancers are the primary determinants of tissue-specific gene expression. Although the majority of our current knowledge of enhancer elements comes from detailed analyses of individual loci, recent progress in epigenomics has led to the development of methods for comprehensive and conservation-independent annotation of cell type-specific enhancers. Here, we discuss the advantages and limitations of different genomic approaches to enhancer mapping and summarize observations that have been afforded by the genome-wide views of enhancer landscapes, with a focus on development. We propose that enhancers serve as information integration hubs, at which instructions encoded by the genome are read in the context of a specific cellular state, signaling milieu and chromatin environment, allowing for exquisitely precise spatiotemporal control of gene expression during embryogenesis. PMID:22487374

  19. A Collaborative Scheduling Model for the Supply-Hub with Multiple Suppliers and Multiple Manufacturers

    PubMed Central

    Lv, Fei; Guan, Xu

    2014-01-01

    This paper investigates a collaborative scheduling model in the assembly system, wherein multiple suppliers have to deliver their components to the multiple manufacturers under the operation of Supply-Hub. We first develop two different scenarios to examine the impact of Supply-Hub. One is that suppliers and manufacturers make their decisions separately, and the other is that the Supply-Hub makes joint decisions with collaborative scheduling. The results show that our scheduling model with the Supply-Hub is a NP-complete problem, therefore, we propose an auto-adapted differential evolution algorithm to solve this problem. Moreover, we illustrate that the performance of collaborative scheduling by the Supply-Hub is superior to separate decision made by each manufacturer and supplier. Furthermore, we also show that the algorithm proposed has good convergence and reliability, which can be applicable to more complicated supply chain environment. PMID:24892104

  20. Pioneer GABA cells comprise a subpopulation of hub neurons in the developing hippocampus

    PubMed Central

    Picardo, M.A.; Guigue, P.; Bonifazi, P.; Batista-Brito, R.; Allene, C.; Ribas, A.; Fishell, G.; Baude, A.; Cossart, R.

    2011-01-01

    Summary Connectivity in the developing hippocampus displays a functional organization particularly effective in supporting network synchronization, as it includes superconnected hub neurons. We have previously shown that hub network function is supported by a subpopulation of GABA neurons. However it is unclear whether hub cells are only transiently present or later develop into distinctive subclasses of interneurons. These questions are difficult to assess given the heterogeneity of the GABA neurons and the poor early expression of markers. To circumvent this conundrum we used “genetic fate mapping” that allows for the selective labelling of GABA neurons based on their place and time of origin. We show that early generated GABA cells form a subpopulation of hub neurons, characterized by an exceptionally widespread axonal arborisation and the ability to single-handedly impact network dynamics when stimulated. Pioneer hub neurons remain into adulthood where they acquire the classical markers of long-range projecting GABA neurons. PMID:21867885

  1. A collaborative scheduling model for the supply-hub with multiple suppliers and multiple manufacturers.

    PubMed

    Li, Guo; Lv, Fei; Guan, Xu

    2014-01-01

    This paper investigates a collaborative scheduling model in the assembly system, wherein multiple suppliers have to deliver their components to the multiple manufacturers under the operation of Supply-Hub. We first develop two different scenarios to examine the impact of Supply-Hub. One is that suppliers and manufacturers make their decisions separately, and the other is that the Supply-Hub makes joint decisions with collaborative scheduling. The results show that our scheduling model with the Supply-Hub is a NP-complete problem, therefore, we propose an auto-adapted differential evolution algorithm to solve this problem. Moreover, we illustrate that the performance of collaborative scheduling by the Supply-Hub is superior to separate decision made by each manufacturer and supplier. Furthermore, we also show that the algorithm proposed has good convergence and reliability, which can be applicable to more complicated supply chain environment.

  2. The AII amacrine cell connectome: a dense network hub

    PubMed Central

    Marc, Robert E.; Anderson, James R.; Jones, Bryan W.; Sigulinsky, Crystal L.; Lauritzen, James S.

    2014-01-01

    The mammalian AII retinal amacrine cell is a narrow-field, multistratified glycinergic neuron best known for its role in collecting scotopic signals from rod bipolar cells and distributing them to ON and OFF cone pathways in a crossover network via a combination of inhibitory synapses and heterocellular AII::ON cone bipolar cell gap junctions. Long considered a simple cell, a full connectomics analysis shows that AII cells possess the most complex interaction repertoire of any known vertebrate neuron, contacting at least 28 different cell classes, including every class of retinal bipolar cell. Beyond its basic role in distributing rod signals to cone pathways, the AII cell may also mediate narrow-field feedback and feedforward inhibition for the photopic OFF channel, photopic ON-OFF inhibitory crossover signaling, and serves as a nexus for a collection of inhibitory networks arising from cone pathways that likely negotiate fast switching between cone and rod vision. Further analysis of the complete synaptic counts for five AII cells shows that (1) synaptic sampling is normalized for anatomic target encounter rates; (2) qualitative targeting is specific and apparently errorless; and (3) that AII cells strongly differentiate partner cohorts by synaptic and/or coupling weights. The AII network is a dense hub connecting all primary retinal excitatory channels via precisely weighted drive and specific polarities. Homologs of AII amacrine cells have yet to be identified in non-mammalians, but we propose that such homologs should be narrow-field glycinergic amacrine cells driving photopic ON-OFF crossover via heterocellular coupling with ON cone bipolar cells and glycinergic synapses on OFF cone bipolar cells. The specific evolutionary event creating the mammalian AII scotopic-photopic hub would then simply be the emergence of large numbers of pure rod bipolar cells. PMID:25237297

  3. The AII amacrine cell connectome: a dense network hub.

    PubMed

    Marc, Robert E; Anderson, James R; Jones, Bryan W; Sigulinsky, Crystal L; Lauritzen, James S

    2014-01-01

    The mammalian AII retinal amacrine cell is a narrow-field, multistratified glycinergic neuron best known for its role in collecting scotopic signals from rod bipolar cells and distributing them to ON and OFF cone pathways in a crossover network via a combination of inhibitory synapses and heterocellular AII::ON cone bipolar cell gap junctions. Long considered a simple cell, a full connectomics analysis shows that AII cells possess the most complex interaction repertoire of any known vertebrate neuron, contacting at least 28 different cell classes, including every class of retinal bipolar cell. Beyond its basic role in distributing rod signals to cone pathways, the AII cell may also mediate narrow-field feedback and feedforward inhibition for the photopic OFF channel, photopic ON-OFF inhibitory crossover signaling, and serves as a nexus for a collection of inhibitory networks arising from cone pathways that likely negotiate fast switching between cone and rod vision. Further analysis of the complete synaptic counts for five AII cells shows that (1) synaptic sampling is normalized for anatomic target encounter rates; (2) qualitative targeting is specific and apparently errorless; and (3) that AII cells strongly differentiate partner cohorts by synaptic and/or coupling weights. The AII network is a dense hub connecting all primary retinal excitatory channels via precisely weighted drive and specific polarities. Homologs of AII amacrine cells have yet to be identified in non-mammalians, but we propose that such homologs should be narrow-field glycinergic amacrine cells driving photopic ON-OFF crossover via heterocellular coupling with ON cone bipolar cells and glycinergic synapses on OFF cone bipolar cells. The specific evolutionary event creating the mammalian AII scotopic-photopic hub would then simply be the emergence of large numbers of pure rod bipolar cells.

  4. The noise generated by a landing gear wheel with hub and rim cavities

    NASA Astrophysics Data System (ADS)

    Wang, Meng; Angland, David; Zhang, Xin

    2017-03-01

    Wheels are one of the major noise sources of landing gears. Accurate numerical predictions of wheel noise can provide an insight into the physical mechanism of landing gear noise generation and can aid in the design of noise control devices. The major noise sources of a 33% scaled isolated landing gear wheel are investigated by simulating three different wheel configurations using high-order numerical simulations to compute the flow field and the FW-H equation to obtain the far-field acoustic pressures. The baseline configuration is a wheel with a hub cavity and two rim cavities. Two additional simulations are performed; one with the hub cavity covered (NHC) and the other with both the hub cavity and rim cavities covered (NHCRC). These simulations isolate the effects of the hub cavity and rim cavities on the overall wheel noise. The surface flow patterns are visualised by shear stress lines and show that the flow separations and attachments on the side of the wheel, in both the baseline and the configuration with only the hub cavity covered, are significantly reduced by covering both the hub and rim cavities. A frequency-domain FW-H equation is used to identify the noise source regions on the surface of the wheel. The tyre is the main low frequency noise source and shows a lift dipole and side force dipole pattern depending on the frequency. The hub cavity is identified as the dominant middle frequency noise source and radiates in a frequency range centered around the first and second depth modes of the cylindrical hub cavity. The rim cavities are the main high-frequency noise sources. With the hub cavity and rim cavities covered, the largest reduction in Overall Sound Pressure Level (OASPL) is achieved in the hub side direction. In the other directivities, there is also a reduction in the radiated sound.

  5. USDA Southwest Regional Hub for Adaptation to and Mitigation of Climate Change

    NASA Astrophysics Data System (ADS)

    Rango, A.; Elias, E.; Steele, C. M.; Havstad, K.

    2014-12-01

    The USDA Southwest (SW) Climate Hub was created in February 2014 to develop risk adaptation and mitigation strategies for coping with climate change effects on agricultural productivity. There are seven regional hubs across the country with three subsidiary hubs. The SW Climate Hub Region is made up of six states: New Mexico, Arizona, Utah, Nevada, California and Hawaii (plus the Trust Territories of the Pacific Islands). The SW Climate Hub has a subsidiary hub located in Davis, California. The Southwest region has high climatic diversity, with the lowest and highest average annual rainfall in the U.S.(6.0 cm in Death Valley, CA and 1168 cm at Mt. Waialeale, HI). There are major deserts in five of the six states, yet most of the states, with exception of Hawaii, depend upon the melting of mountain snowpacks for their surface water supply. Additionally, many of the agricultural areas of the SW Regional Hub depend upon irrigation water to maintain productivity. Scientific climate information developed by the Hub will be used for climate-smart decision making. To do this, the SW Regional Hub will rely upon existing infrastructure of the Cooperative Extension Service at Land-Grant State Universities. Extension service and USDA-NRCS personnel have existing networks to communicate with stakeholders (farmers, ranchers, and forest landowners) through meetings and workshops which have already started in the six states. Outreach through the development of a weather and climate impact modules designed for seventh grade students and their teachers will foster education of future generations of rural land managers. We will be synthesizing and evaluating existing reports, literature and information on regional climate projections, water resources, and agricultural adaptation strategies related to climate in the Southwest. The results will be organized in a spatial format and provided through the SW Hub website (http://swclimatehub.info) and peer-reviewed articles.

  6. Induction of bilateral plasticity in sensory cortical maps by small unilateral cortical infarcts in rats.

    PubMed

    Reinecke, S; Dinse, H R; Reinke, H; Witte, O W

    2003-02-01

    Behavioural impairments caused by brain lesions show a considerable, though often incomplete, recovery. It is hypothesized that cortical and subcortical plasticity of sensory representations contribute to this recovery. In the hindpaw representation of somatosensory cortex of adult rats we investigated the effects of focal unilateral cortical lesions on remote areas. Cortical lesions with a diameter of approximately 2 mm were induced in the parietal cortex by photothrombosis with the photosensitive dye Rose Bengal. Subsequently, animals were kept in standard cages for 7 days. On day seven, animals were anaesthetized and cutaneous receptive fields in the cortical hindpaw representations ipsi- and contralateral to the lesion were constructed from extracellular recordings of neurons in layer IV using glass microelectrodes. Receptive fields in the lesioned animals were compared to receptive fields measured in nonlesioned animals serving as controls. Quantitative analysis of receptive fields revealed a significant increase in size in the lesioned animals. This doubling in receptive field size was observed equally in the hemispheres ipsi- and contralateral to the lesion. The results indicate that the functional consequences of restricted cortical lesions are not limited to the area surrounding the lesion, but affect the cortical maps on the contralateral, nonlesioned hemisphere.

  7. Visualization of Cortical Dynamics

    NASA Astrophysics Data System (ADS)

    Grinvald, Amiram

    2003-03-01

    Recent progress in studies of cortical dynamics will be reviewed including the combination of real time optical imaging based on voltage sensitive dyes, single and multi- unit recordings, LFP, intracellular recordings and microstimulation. To image the flow of neuronal activity from one cortical site to the next, in real time, we have used optical imaging based on newly designed voltage sensitive dyes and a Fuji 128x 128 fast camera which we modified. A factor of 20-40 fold improvement in the signal to noise ratio was obtained with the new dye during in vivo imaging experiments. This improvements has facilitates the exploration of cortical dynamics without signal averaging in the millisecond time domain. We confirmed that the voltage sensitive dye signal indeed reflects membrane potential changes in populations of neurons by showing that the time course of the intracellular activity recorded intracellularly from a single neuron was highly correlated in many cases with the optical signal from a small patch of cortex recorded nearby. We showed that the firing of single cortical neurons is not a random process but occurs when the on-going pattern of million of neurons is similar to the functional architecture map which correspond to the tuning properties of that neuron. Chronic optical imaging, combined with electrical recordings and microstimulation, over a long period of times of more than a year, was successfully applied also to the study of higher brain functions in the behaving macaque monkey.

  8. Cortical control of facial expression.

    PubMed

    Müri, René M

    2016-06-01

    The present Review deals with the motor control of facial expressions in humans. Facial expressions are a central part of human communication. Emotional face expressions have a crucial role in human nonverbal behavior, allowing a rapid transfer of information between individuals. Facial expressions can be either voluntarily or emotionally controlled. Recent studies in nonhuman primates and humans have revealed that the motor control of facial expressions has a distributed neural representation. At least five cortical regions on the medial and lateral aspects of each hemisphere are involved: the primary motor cortex, the ventral lateral premotor cortex, the supplementary motor area on the medial wall, and the rostral and caudal cingulate cortex. The results of studies in humans and nonhuman primates suggest that the innervation of the face is bilaterally controlled for the upper part and mainly contralaterally controlled for the lower part. Furthermore, the primary motor cortex, the ventral lateral premotor cortex, and the supplementary motor area are essential for the voluntary control of facial expressions. In contrast, the cingulate cortical areas are important for emotional expression, because they receive input from different structures of the limbic system.

  9. A case of cortical deafness and anarthria.

    PubMed

    Kaga, Kimitaka; Nakamura, Masako; Takayama, Yoshihiro; Momose, Hiromitsu

    2004-03-01

    Generally, cortical deafness is not complicated by anarthria and cortical anarthria does not affect auditory perception. We report a case of simultaneous progressive cortical deafness and anarthria. At the age of 70 years, the patient, a woman, noticed hearing problems when using the telephone, which worsened rapidly over the next 2 years. She was then referred to our hospital for further examinations of her hearing problems. Auditory tests revealed threshold elevation in the low and middle frequencies on pure-tone audiometry, a maximum speech discrimination of 25% and normal otoacoustic emissions and auditory brainstem, middle- and long-latency responses. An articulation test revealed abnormal pronunciation. Because of these problems only written and not verbal communication was possible; her ability to read and write was unimpaired. She showed no other neurological problems. Brain MRI demonstrated atrophic changes of the auditory cortex and Wernicke's language center and PET suggested low uptake of (18F) 2-fluoro-2-deoxy-d-glucose around the Sylvian fissures in both hemispheres. Neurologically, the patient was suspected of having progressive aphasia or frontotemporal dementia. Her cortical deafness and anarthria are believed to be early signs of this entity.

  10. 76 FR 10328 - Grant of Authority for Subzone Status; Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-24

    ... Turbine Nacelles, Hubs, Blades and Towers), Brighton, Denver, Pueblo, and Windsor, CO Pursuant to its... turbine nacelle, hub, blade and tower manufacturing and warehousing facilities of Vestas Nacelles America... manufacturing and warehousing of wind turbine nacelles, hubs, blades and towers at the Vestas Nacelles...

  11. The role of conceptual knowledge in understanding synaesthesia: Evaluating contemporary findings from a "hub-and-spokes" perspective.

    PubMed

    Chiou, Rocco; Rich, Anina N

    2014-01-01

    maintained within a supramodal "hub," while the subjective (bodily) experience of its resultant concurrent (e.g., a color) may then require activation of "spokes" in the perception-related cortices. This hypothesized "hub-and-spoke" structure would engage a distributed network of cortical regions and may account for the full breadth of this intriguing phenomenon.

  12. The role of conceptual knowledge in understanding synaesthesia: Evaluating contemporary findings from a “hub-and-spokes” perspective

    PubMed Central

    Chiou, Rocco

    2014-01-01

    maintained within a supramodal “hub,” while the subjective (bodily) experience of its resultant concurrent (e.g., a color) may then require activation of “spokes” in the perception-related cortices. This hypothesized “hub-and-spoke” structure would engage a distributed network of cortical regions and may account for the full breadth of this intriguing phenomenon. PMID:24653707

  13. Merlin/ERM proteins establish cortical asymmetry and centrosome position

    PubMed Central

    Hebert, Alan M.; DuBoff, Brian; Casaletto, Jessica B.; Gladden, Andrew B.; McClatchey, Andrea I.

    2012-01-01

    The ability to generate asymmetry at the cell cortex underlies cell polarization and asymmetric cell division. Here we demonstrate a novel role for the tumor suppressor Merlin and closely related ERM proteins (Ezrin, Radixin, and Moesin) in generating cortical asymmetry in the absence of external cues. Our data reveal that Merlin functions to restrict the cortical distribution of the actin regulator Ezrin, which in turn positions the interphase centrosome in single epithelial cells and three-dimensional organotypic cultures. In the absence of Merlin, ectopic cortical Ezrin yields mispositioned centrosomes, misoriented spindles, and aberrant epithelial architecture. Furthermore, in tumor cells with centrosome amplification, the failure to restrict cortical Ezrin abolishes centrosome clustering, yielding multipolar mitoses. These data uncover fundamental roles for Merlin/ERM proteins in spatiotemporally organizing the cell cortex and suggest that Merlin's role in restricting cortical Ezrin may contribute to tumorigenesis by disrupting cell polarity, spindle orientation, and, potentially, genome stability. PMID:23249734

  14. Lineage-specific laminar organization of cortical GABAergic interneurons.

    PubMed

    Ciceri, Gabriele; Dehorter, Nathalie; Sols, Ignasi; Huang, Z Josh; Maravall, Miguel; Marín, Oscar

    2013-09-01

    In the cerebral cortex, pyramidal cells and interneurons are generated in distant germinal zones, and so the mechanisms that control their precise assembly into specific microcircuits remain an enigma. Here we report that cortical interneurons labeled at the clonal level do not distribute randomly but rather have a strong tendency to cluster in the mouse neocortex. This behavior is common to different classes of interneurons, independently of their origin. Interneuron clusters are typically contained within one or two adjacent cortical layers, are largely formed by isochronically generated neurons and populate specific layers, as revealed by unbiased hierarchical clustering methods. Our results suggest that different progenitor cells give rise to interneurons populating infra- and supragranular cortical layers, which challenges current views of cortical neurogenesis. Thus, specific lineages of cortical interneurons seem to be produced to primarily mirror the laminar structure of the cerebral cortex, rather than its columnar organization.

  15. Fatigue based design and analysis of wheel hub for Student formula car by Simulation Approach

    NASA Astrophysics Data System (ADS)

    Gowtham, V.; Ranganathan, A. S.; Satish, S.; Alexis, S. John; Siva kumar, S.

    2016-09-01

    In the existing design of Wheel hub used for Student formula cars, the brake discs cannot be removed easily since the disc is mounted in between the knuckle and hub. In case of bend or any other damage to the disc, the replacement of the disc becomes difficult. Further using OEM hub and knuckle that are used for commercial vehicles will result in increase of unsprung mass, which should be avoided in Student formula cars for improving the performance. In this design the above mentioned difficulties have been overcome by redesigning the hub in such a way that the brake disc could be removed easily by just removing the wheel and the caliper and also it will have reduced weight when compared to existing OEM hub. A CAD Model was developed based on the required fatigue life cycles. The forces acting on the hub were calculated and linear static structural analysis was performed on the wheel hub for three different materials using ANSYS Finite Element code V 16.2. The theoretical fatigue strength was compared with the stress obtained from the structural analysis for each material.

  16. Hubs and Authorities in the World Trade Network Using a Weighted HITS Algorithm

    PubMed Central

    Deguchi, Tsuyoshi; Takahashi, Katsuhide; Takayasu, Hideki; Takayasu, Misako

    2014-01-01

    We investigate the economic hubs and authorities of the world trade network (WTN) from to , an era of rapid economic globalization. Using a well-defined weighted hyperlink-induced topic search (HITS) algorithm, we can calculate the values of the weighted HITS hub and authority for each country in a conjugate way. In the context of the WTN, authority values are large for countries with significant imports from large hub countries, and hub values are large for countries with significant exports to high-authority countries. The United States was the largest economic authority in the WTN from to . The authority value of the United States has declined since , and China has now become the largest hub in the WTN. At the same time, China's authority value has grown as China is transforming itself from the “factory of the world” to the “market of the world.” European countries show a tendency to trade mostly within the European Union, which has decreased Europe's hub and authority values. Japan's authority value has increased slowly, while its hub value has declined. These changes are consistent with Japan's transition from being an export-driven economy in its high economic growth era in the latter half of the twentieth century to being a more mature, economically balanced nation. PMID:25050940

  17. Hubs and authorities in the world trade network using a weighted HITS algorithm.

    PubMed

    Deguchi, Tsuyoshi; Takahashi, Katsuhide; Takayasu, Hideki; Takayasu, Misako

    2014-01-01

    We investigate the economic hubs and authorities of the world trade network (WTN) from 1992 to 2012, an era of rapid economic globalization. Using a well-defined weighted hyperlink-induced topic search (HITS) algorithm, we can calculate the values of the weighted HITS hub and authority for each country in a conjugate way. In the context of the WTN, authority values are large for countries with significant imports from large hub countries, and hub values are large for countries with significant exports to high-authority countries. The United States was the largest economic authority in the WTN from 1992 to 2012. The authority value of the United States has declined since 2001, and China has now become the largest hub in the WTN. At the same time, China's authority value has grown as China is transforming itself from the "factory of the world" to the "market of the world." European countries show a tendency to trade mostly within the European Union, which has decreased Europe's hub and authority values. Japan's authority value has increased slowly, while its hub value has declined. These changes are consistent with Japan's transition from being an export-driven economy in its high economic growth era in the latter half of the twentieth century to being a more mature, economically balanced nation.

  18. Examination of the relationship between essential genes in PPI network and hub proteins in reverse nearest neighbor topology

    PubMed Central

    2010-01-01

    Background In many protein-protein interaction (PPI) networks, densely connected hub proteins are more likely to be essential proteins. This is referred to as the "centrality-lethality rule", which indicates that the topological placement of a protein in PPI network is connected with its biological essentiality. Though such connections are observed in many PPI networks, the underlying topological properties for these connections are not yet clearly understood. Some suggested putative connections are the involvement of essential proteins in the maintenance of overall network connections, or that they play a role in essential protein clusters. In this work, we have attempted to examine the placement of essential proteins and the network topology from a different perspective by determining the correlation of protein essentiality and reverse nearest neighbor topology (RNN). Results The RNN topology is a weighted directed graph derived from PPI network, and it is a natural representation of the topological dependences between proteins within the PPI network. Similar to the original PPI network, we have observed that essential proteins tend to be hub proteins in RNN topology. Additionally, essential genes are enriched in clusters containing many hub proteins in RNN topology (RNN protein clusters). Based on these two properties of essential genes in RNN topology, we have proposed a new measure; the RNN cluster centrality. Results from a variety of PPI networks demonstrate that RNN cluster centrality outperforms other centrality measures with regard to the proportion of selected proteins that are essential proteins. We also investigated the biological importance of RNN clusters. Conclusions This study reveals that RNN cluster centrality provides the best correlation of protein essentiality and placement of proteins in PPI network. Additionally, merged RNN clusters were found to be topologically important in that essential proteins are significantly enriched in RNN clusters

  19. Sparse and powerful cortical spikes.

    PubMed

    Wolfe, Jason; Houweling, Arthur R; Brecht, Michael

    2010-06-01

    Activity in cortical networks is heterogeneous, sparse and often precisely timed. The functional significance of sparseness and precise spike timing is debated, but our understanding of the developmental and synaptic mechanisms that shape neuronal discharge patterns has improved. Evidence for highly specialized, selective and abstract cortical response properties is accumulating. Singe-cell stimulation experiments demonstrate a high sensitivity of cortical networks to the action potentials of some, but not all, single neurons. It is unclear how this sensitivity of cortical networks to small perturbations comes about and whether it is a generic property of cortex. The unforeseen sensitivity to cortical spikes puts serious constraints on the nature of neural coding schemes.

  20. Early and Phasic Cortical Metabolic Changes in Vestibular Neuritis Onset

    PubMed Central

    Alessandrini, Marco; Pagani, Marco; Napolitano, Bianca; Micarelli, Alessandro; Candidi, Matteo; Bruno, Ernesto; Chiaravalloti, Agostino; Di Pietro, Barbara; Schillaci, Orazio

    2013-01-01

    Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF) are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN), that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [18F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients’ cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34) and Temporal (BA 38) cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34) and of the emotional response to the new pathologic condition (BA 38) respectively. These interpretations were further supported by changes in patients’ subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding knowledge about

  1. Early and phasic cortical metabolic changes in vestibular neuritis onset.

    PubMed

    Alessandrini, Marco; Pagani, Marco; Napolitano, Bianca; Micarelli, Alessandro; Candidi, Matteo; Bruno, Ernesto; Chiaravalloti, Agostino; Di Pietro, Barbara; Schillaci, Orazio

    2013-01-01

    Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF) are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN), that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [(18)F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients' cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34) and Temporal (BA 38) cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34) and of the emotional response to the new pathologic condition (BA 38) respectively. These interpretations were further supported by changes in patients' subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding knowledge about

  2. Classification of gene expression data: A hubness-aware semi-supervised approach.

    PubMed

    Buza, Krisztian

    2016-04-01

    Classification of gene expression data is the common denominator of various biomedical recognition tasks. However, obtaining class labels for large training samples may be difficult or even impossible in many cases. Therefore, semi-supervised classification techniques are required as semi-supervised classifiers take advantage of unlabeled data. Gene expression data is high-dimensional which gives rise to the phenomena known under the umbrella of the curse of dimensionality, one of its recently explored aspects being the presence of hubs or hubness for short. Therefore, hubness-aware classifiers have been developed recently, such as Naive Hubness-Bayesian k-Nearest Neighbor (NHBNN). In this paper, we propose a semi-supervised extension of NHBNN which follows the self-training schema. As one of the core components of self-training is the certainty score, we propose a new hubness-aware certainty score. We performed experiments on publicly available gene expression data. These experiments show that the proposed classifier outperforms its competitors. We investigated the impact of each of the components (classification algorithm, semi-supervised technique, hubness-aware certainty score) separately and showed that each of these components are relevant to the performance of the proposed approach. Our results imply that our approach may increase classification accuracy and reduce computational costs (i.e., runtime). Based on the promising results presented in the paper, we envision that hubness-aware techniques will be used in various other biomedical machine learning tasks. In order to accelerate this process, we made an implementation of hubness-aware machine learning techniques publicly available in the PyHubs software package (http://www.biointelligence.hu/pyhubs) implemented in Python, one of the most popular programming languages of data science. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. E-hubs: the new B2B (business-to-business) marketplaces.

    PubMed

    Kaplan, S; Sawhney, M

    2000-01-01

    Electronic hubs--Internet-based intermediaries that host electronic marketplaces and mediate transactions among businesses--are generating a lot of interest. Companies like Ariba, Chemdex, and Commerce One have already attained breathtaking stock market capitalizations. Venture capitalists are pouring money into more business-to-business start-ups. Even industrial stalwarts like GM and Ford are making plans to set up their own Web markets. As new entrants with new business models pour into the business-to-business space, it's increasingly difficult to make sense of the landscape. This article provides a blueprint of the e-hub arena. The authors start by looking at the two dimensions of purchasing: what businesses buy--manufacturing inputs or operating inputs--and how they buy--through systematic sourcing or spot sourcing. They classify B2B e-hubs into four categories: MRO hubs, yield managers, exchanges, and catalog hubs, and they discuss each type in detail. Drilling deeper into this B2B matrix, the authors look at how e-hubs create value--through aggregation and matching--and explain when each mechanism works best. They also examine the biases of e-hubs. Although many e-hubs are neutral--they're operated by independent third parties--some favor the buyers or sellers. The authors explain the differences and discuss the pros and cons of each position. The B2B marketplace is changing rapidly. This framework helps buyers, sellers, and market makers navigate the landscape by explaining what the different hubs do and how they add the most value.

  4. Lhx2 regulates the timing of β-catenin-dependent cortical neurogenesis.

    PubMed

    Hsu, Lea Chia-Ling; Nam, Sean; Cui, Yi; Chang, Ching-Pu; Wang, Chia-Fang; Kuo, Hung-Chih; Touboul, Jonathan D; Chou, Shen-Ju

    2015-09-29

    The timing of cortical neurogenesis has a major effect on the size and organization of the mature cortex. The deletion of the LIM-homeodomain transcription factor Lhx2 in cortical progenitors by Nestin-cre leads to a dramatically smaller cortex. Here we report that Lhx2 regulates the cortex size by maintaining the cortical progenitor proliferation and delaying the initiation of neurogenesis. The loss of Lhx2 in cortical progenitors results in precocious radial glia differentiation and a temporal shift of cortical neurogenesis. We further investigated the underlying mechanisms at play and demonstrated that in the absence of Lhx2, the Wnt/β-catenin pathway failed to maintain progenitor proliferation. We developed and applied a mathematical model that reveals how precocious neurogenesis affected cortical surface and thickness. Thus, we concluded that Lhx2 is required for β-catenin function in maintaining cortical progenitor proliferation and controls the timing of cortical neurogenesis.

  5. Periodicity hub and nested spirals in the phase diagram of a simple resistive circuit.

    PubMed

    Bonatto, Cristian; Gallas, Jason A C

    2008-08-01

    We report the discovery of a remarkable "periodicity hub" inside the chaotic phase of an electronic circuit containing two diodes as a nonlinear resistance. The hub is a focal point from where an infinite hierarchy of nested spirals emanates. By suitably tuning two reactances simultaneously, both current and voltage may have their periodicity increased continuously without bound and without ever crossing the surrounding chaotic phase. Familiar period-adding current and voltage cascades are shown to be just restricted one-parameter slices of an exceptionally intricate and very regular onionlike parameter surface centered at the focal hub which organizes all the dynamics.

  6. Subplate Neurons: Crucial Regulators of Cortical Development and Plasticity

    PubMed Central

    Kanold, Patrick O.

    2009-01-01

    The developing cerebral cortex contains a distinct class of cells, subplate neurons, which form one of the first functional cortical circuits. Subplate neurons reside in the cortical white matter, receive thalamic inputs and project into the developing cortical plate, mostly to layer 4. Subplate neurons are present at key time points during development. Removal of subplate neurons profoundly affects cortical development. Subplate removal in visual cortex prevents the maturation of thalamocortical synapse, the maturation of inhibition in layer 4, the development of orientation selective responses in individual cortical neurons, and the formation of ocular dominance columns. In addition, monocular deprivation during development reveals that ocular dominance plasticity is paradoxical in the absence of subplate neurons. Because subplate neurons projecting to layer 4 are glutamatergic, these diverse deficits following subplate removal were hypothesized to be due to lack of feed-forward thalamic driven cortical excitation. A computational model of the developing thalamocortical pathway incorporating feed-forward excitatory subplate projections replicates both normal development and plasticity of ocular dominance as well as the effects of subplate removal. Therefore, we postulate that feed-forward excitatory projections from subplate neurons into the developing cortical plate enhance correlated activity between thalamus and layer 4 and, in concert with Hebbian learning rules in layer 4, allow maturational and plastic processes in layer 4 to commence. Thus subplate neurons are a crucial regulator of cortical development and plasticity, and damage to these neurons might play a role in the pathology of many neurodevelopmental disorders. PMID:19738926

  7. Purely Cortical Anaplastic Ependymoma

    PubMed Central

    Romero, Flávio Ramalho; Zanini, Marco Antônio; Ducati, Luis Gustavo; Vital, Roberto Bezerra; de Lima Neto, Newton Moreira; Gabarra, Roberto Colichio

    2012-01-01

    Ependymomas are glial tumors derived from ependymal cells lining the ventricles and the central canal of the spinal cord. It may occur outside the ventricular structures, representing the extraventicular form, or without any relationship of ventricular system, called ectopic ependymona. Less than fifteen cases of ectopic ependymomas were reported and less than five were anaplastic. We report a rare case of pure cortical ectopic anaplastic ependymoma. PMID:23119204

  8. [Posterior cortical atrophy].

    PubMed

    Solyga, Volker Moræus; Western, Elin; Solheim, Hanne; Hassel, Bjørnar; Kerty, Emilia

    2015-06-02

    Posterior cortical atrophy is a neurodegenerative condition with atrophy of posterior parts of the cerebral cortex, including the visual cortex and parts of the parietal and temporal cortices. It presents early, in the 50s or 60s, with nonspecific visual disturbances that are often misinterpreted as ophthalmological, which can delay the diagnosis. The purpose of this article is to present current knowledge about symptoms, diagnostics and treatment of this condition. The review is based on a selection of relevant articles in PubMed and on the authors' own experience with the patient group. Posterior cortical atrophy causes gradually increasing impairment in reading, distance judgement, and the ability to perceive complex images. Examination of higher visual functions, neuropsychological testing, and neuroimaging contribute to diagnosis. In the early stages, patients do not have problems with memory or insight, but cognitive impairment and dementia can develop. It is unclear whether the condition is a variant of Alzheimer's disease, or whether it is a separate disease entity. There is no established treatment, but practical measures such as the aid of social care workers, telephones with large keypads, computers with voice recognition software and audiobooks can be useful. Currently available treatment has very limited effect on the disease itself. Nevertheless it is important to identify and diagnose the condition in its early stages in order to be able to offer patients practical assistance in their daily lives.

  9. Posterior Cortical Atrophy

    PubMed Central

    Crutch, Sebastian J; Lehmann, Manja; Schott, Jonathan M; Rabinovici, Gil D; Rossor, Martin N; Fox, Nick C

    2013-01-01

    Posterior cortical atrophy (PCA) is a neurodegenerative syndrome that is characterized by a progressive decline in visuospatial, visuoperceptual, literacy and praxic skills. The progressive neurodegeneration affecting parietal, occipital and occipito-temporal cortices which underlies PCA is attributable to Alzheimer's disease (AD) in the majority of patients. However, alternative underlying aetiologies including Dementia with Lewy Bodies (DLB), corticobasal degeneration (CBD) and prion disease have also been identified, and not all PCA patients have atrophy on clinical imaging. This heterogeneity has led to diagnostic and terminological inconsistencies, caused difficulty comparing studies from different centres, and limited the generalizability of clinical trials and investigations of factors driving phenotypic variability. Significant challenges remain in identifying the factors associated with both the selective vulnerability of posterior cortical regions and the young age of onset seen in PCA. Greater awareness of the syndrome and agreement over the correspondence between syndrome-and disease-level classifications are required in order to improve diagnostic accuracy, research study design and clinical management. PMID:22265212

  10. Adult Visual Cortical Plasticity

    PubMed Central

    Gilbert, Charles D.; Li, Wu

    2012-01-01

    The visual cortex has the capacity for experience dependent change, or cortical plasticity, that is retained throughout life. Plasticity is invoked for encoding information during perceptual learning, by internally representing the regularities of the visual environment, which is useful for facilitating intermediate level vision - contour integration and surface segmentation. The same mechanisms have adaptive value for functional recovery after CNS damage, such as that associated with stroke or neurodegenerative disease. A common feature to plasticity in primary visual cortex (V1) is an association field that links contour elements across the visual field. The circuitry underlying the association field includes a plexus of long range horizontal connections formed by cortical pyramidal cells. These connections undergo rapid and exuberant sprouting and pruning in response to removal of sensory input, which can account for the topographic reorganization following retinal lesions. Similar alterations in cortical circuitry may be involved in perceptual learning, and the changes observed in V1 may be representative of how learned information is encoded throughout the cerebral cortex. PMID:22841310

  11. Cortical reorganization in children with cochlear implants.

    PubMed

    Gilley, Phillip M; Sharma, Anu; Dorman, Michael F

    2008-11-06

    Congenital deafness leads to atypical organization of the auditory nervous system. However, the extent to which auditory pathways reorganize during deafness is not well understood. We recorded cortical auditory evoked potentials in normal hearing children and in congenitally deaf children fitted with cochlear implants. High-density EEG and source modeling revealed principal activity from auditory cortex in normal hearing and early implanted children. However, children implanted after a critical period of seven years revealed activity from parietotemporal cortex in response to auditory stimulation, demonstrating reorganized cortical pathways. Reorganization of central auditory pathways is limited by the age at which implantation occurs, and may help explain the benefits and limitations of implantation in congenitally deaf children.

  12. Extensive cortical involvement in leptomeningeal carcinomatosis.

    PubMed

    Ayzenberg, I; Börnke, C; Tönnes, C; Ziebarth, W; Lavrov, A; Lukas, C

    2012-12-01

    We present a 77-year-old previously well patient with facial asymmetry and progressive weakness of the lower extremities. An initial MRI revealed slight contrast enhancement of the meninges. Three consecutive cerebrospinal fluid examinations demonstrated low glucose concentration, marked elevation of total protein and moderate pleocytosis. No tumor cells, fungi, acid-fast bacilli or mycobacterial DNA were found. The patient's level of consciousness deteriorated dramatically, and follow-up MRI showed widespread extensive cortical hyperintensities. The lesions showed restricted diffusion on diffusion-weighted images as well as low values on the corresponding apparent diffusion coefficient maps, the changes consistent with diffuse cytotoxic edema. Neuropathological examination findings were of leptomeningeal carcinomatosis (LMC) with diffuse continuous infiltration of the cerebral cortex, cerebellum and spinal cord. The autopsy revealed a subcentimetre adenocarcinoma of the lung. To our knowledge, this is the first report demonstrating extensive cortical involvement in adenocarcinomatous LMC.

  13. Perceptual Incongruence Influences Bistability and Cortical Activation

    PubMed Central

    Brouwer, Gijs Joost; Tong, Frank; Hagoort, Peter; van Ee, Raymond

    2009-01-01

    We employed a parametric psychophysical design in combination with functional imaging to examine the influence of metric changes in perceptual incongruence on perceptual alternation rates and cortical responses. Subjects viewed a bistable stimulus defined by incongruent depth cues; bistability resulted from incongruence between binocular disparity and monocular perspective cues that specify different slants (slant rivalry). Psychophysical results revealed that perceptual alternation rates were positively correlated with the degree of perceived incongruence. Functional imaging revealed systematic increases in activity that paralleled the psychophysical results within anterior intraparietal sulcus, prior to the onset of perceptual alternations. We suggest that this cortical activity predicts the frequency of subsequent alternations, implying a putative causal role for these areas in initiating bistable perception. In contrast, areas implicated in form and depth processing (LOC and V3A) were sensitive to the degree of slant, but failed to show increases in activity when these cues were in conflict. PMID:19333385

  14. Two-photon laser scanning microscopy imaging of intact spinal cord and cerebral cortex reveals requirement for CXCR6 and neuroinflammation in immune cell infiltration of cortical injury sites

    PubMed Central

    Kim, Jiyun V.; Jiang, Ning; Tadokoro, Carlos E.; Liu, Liping; Ransohoff, Richard M.; Lafaille, Juan J.; Dustin, Michael L.

    2009-01-01

    The mouse spinal cord is an important site for autoimmune and injury models. Skull thinning surgery provides a minimally invasive window for microscopy of the mouse cerebral cortex, but there are no parallel methods for the spinal cord. We introduce a novel, facile and inexpensive method for two-photon laser scanning microscopy of the intact spinal cord in the mouse by taking advantage of the naturally accessible intervertebral space. These are powerful methods when combined with gene-targeted mice in which endogenous immune cells are labeled with green fluorescent protein (GFP). We first demonstrate that generation of the intervertebral window does not elicit a reaction of GFP+ microglial cells in CX3CR1gfp/+ mice. We next demonstrate a distinct rostro-caudal migration of GFP+ immune cells in the spinal cord of CXCR6gfp/+ mice during active experimental autoimmune encephalomyelitis (EAE). Interestingly, infiltration of the cerebral cortex by GFP+ cells in these mice required three conditions: EAE induction, cortical injury and expression of CXCR6 on immune cells. PMID:19800886

  15. Proof test of hybrid shrink fits with ceramic hub

    NASA Astrophysics Data System (ADS)

    Wagner, M.; Binz, H.

    2011-10-01

    Advanced ceramic machine components are required in many applications because of their specific material properties like high hardness, resistance to chemicals, corrosion and wear, low specific weight etc. The most suitable shaft-hub connection to ceramics is an interference fit assembly because it is free of geometrical notches and transmission of forces takes place in a large area. Such a shrink fit is rated for endurance strength when the stress intensity factor is below the specific value KI0 where no crack growth occurs. The total component suddenly fails, when the stress intensity factor exceeds the KIC value. The load to the press fit during the joining process, caused by the interference of the assembly, could be regulated by ambient conditions. In case of undetected material defects or microcracks in the ceramic and if the stress intensity is below KIC, the ceramic will not fail but a crack could grow. Thus, the joining process only seems to be a proof test. When the load during operation leads to a stress intensity that remains higher than KI0 the crack grows until the whole ceramic component fails. This effect was verified in tests at the Institute for Engineering Design and Industrial Design.

  16. Hub nodes inhibit the outbreak of epidemic under voluntary vaccination

    NASA Astrophysics Data System (ADS)

    Zhang, Haifeng; Zhang, Jie; Zhou, Changsong; Small, Michael; Wang, Binghong

    2010-02-01

    It is commonly believed that epidemic spreading on scale-free networks is difficult to control and that the disease can spread even with a low infection rate, lacking an epidemic threshold. In this paper, we study epidemic spreading on complex networks under the framework of game theory, in which a voluntary vaccination strategy is incorporated. In particular, individuals face the 'dilemma' of vaccination: they have to decide whether or not to vaccinate according to the trade-off between the risk and the side effects or cost of vaccination. Remarkably and quite excitingly, we find that disease outbreak can be more effectively inhibited on scale-free networks than on random networks. This is because the hub nodes of scale-free networks are more inclined to take self-vaccination after balancing the pros and cons. This result is encouraging as it indicates that real-world networks, which are often claimed to be scale free, can be favorably and easily controlled under voluntary vaccination. Our work provides a way of understanding how to prevent the outbreak of diseases under voluntary vaccination, and is expected to provide valuable information on effective disease control and appropriate decision-making.

  17. Creating a Linked Data Hub in the Geosciences

    NASA Astrophysics Data System (ADS)

    Narock, T. W.; Rozell, E. A.; Robinson, E. M.

    2012-12-01

    Linked data is a paradigm for publishing data on the Web by using, among other things, non-proprietary data formats and resolvable identifiers for things in your dataset. One linked data initiative, DBPedia, is widely used as a "crystallization point" for linked data on the Web. It serves as a hub for links from external datasets covering a broad variety of domains. Within the Earth Science Information Partnership (ESIP) efforts have begun to create a similar crystallization point for linked data in the geosciences. The initial project was created by converting more than 100,000 abstracts from the American Geophysical Union (AGU) into linked data using the Resource Description Framework. Like the Wikipedia data DBPedia is derived from, AGU publications have extremely broad coverage of topics in the geosciences. To better characterize the network, we have linked this AGU data to ESIP meeting and membership data, as well as to National Science Foundation-funded research projects. In doing so, we can visualize connections between different collaborative clusters like the ESIP Community or NSF grantees within the broader Geosciences communities that attend AGU conferences. Efforts to extend this project include - the ability to annotate abstracts, provide links to referenced tools or datasets, and the enabling of a crowd-sourcing approach to co-reference resolution.

  18. PAR-5 is a PARty hub in the germline

    PubMed Central

    Aristizábal-Corrales, David; Schwartz Jr, Simo; Cerón, Julián

    2013-01-01

    As our understanding of how molecular machineries work expands, an increasing number of proteins that appear as regulators of different processes have been identified. These proteins are hubs within and among functional networks. The 14-3-3 protein family is involved in multiple cellular pathways and, therefore, influences signaling in several disease processes, from neurobiological disorders to cancer. As a consequence, 14-3-3 proteins are currently being investigated as therapeutic targets. Moreover, 14-3-3 protein levels have been associated with resistance to chemotherapies. There are seven 14-3-3 genes in humans, while Caenorhabditis elegans only possesses two, namely par-5 and ftt-2. Among the C. elegans scientific community, par-5 is mainly recognized as one of the par genes that is essential for the asymmetric first cell division in the embryo. However, a recent study from our laboratory describes roles of par-5 in germ cell proliferation and in the cellular response to DNA damage induced by genotoxic agents. In this review, we explore the broad functionality of 14-3-3 proteins in C. elegans and comment on the potential use of worms for launching a drugs/modifiers discovery platform for the therapeutic regulation of 14-3-3 function in cancer. PMID:24058859

  19. Assessing wave energy effects on biodiversity: the wave hub experience.

    PubMed

    Witt, M J; Sheehan, E V; Bearhop, S; Broderick, A C; Conley, D C; Cotterell, S P; Crow, E; Grecian, W J; Halsband, C; Hodgson, D J; Hosegood, P; Inger, R; Miller, P I; Sims, D W; Thompson, R C; Vanstaen, K; Votier, S C; Attrill, M J; Godley, B J

    2012-01-28

    Marine renewable energy installations harnessing energy from wind, wave and tidal resources are likely to become a large part of the future energy mix worldwide. The potential to gather energy from waves has recently seen increasing interest, with pilot developments in several nations. Although technology to harness wave energy lags behind that of wind and tidal generation, it has the potential to contribute significantly to energy production. As wave energy technology matures and becomes more widespread, it is likely to result in further transformation of our coastal seas. Such changes are accompanied by uncertainty regarding their impacts on biodiversity. To date, impacts have not been assessed, as wave energy converters have yet to be fully developed. Therefore, there is a pressing need to build a framework of understanding regarding the potential impacts of these technologies, underpinned by methodologies that are transferable and scalable across sites to facilitate formal meta-analysis. We first review the potential positive and negative effects of wave energy generation, and then, with specific reference to our work at the Wave Hub (a wave energy test site in southwest England, UK), we set out the methodological approaches needed to assess possible effects of wave energy on biodiversity. We highlight the need for national and international research clusters to accelerate the implementation of wave energy, within a coherent understanding of potential effects-both positive and negative.

  20. Cortical control of anticipatory postural adjustments prior to stepping.

    PubMed

    Varghese, J P; Merino, D M; Beyer, K B; McIlroy, W E

    2016-01-28

    Human bipedal balance control is achieved either reactively or predictively by a distributed network of neural areas within the central nervous system with a potential role for cerebral cortex. While the role of the cortex in reactive balance has been widely explored, only few studies have addressed the cortical activations related to predictive balance control. The present study investigated the cortical activations related to the preparation and execution of anticipatory postural adjustment (APA) that precede a step. This study also examined whether the preparatory cortical activations related to a specific movement is dependent on the context of control (postural component vs. focal component). Ground reaction forces and electroencephalographic (EEG) data were recorded from 14 healthy adults while they performed lateral weight shift and lateral stepping with and without initially preloading their weight to the stance leg. EEG analysis revealed that there were distinct movement-related potentials (MRPs) with concurrent event-related desynchronization (ERD) of mu and beta rhythms prior to the onset of APA and also to the onset of foot-off during lateral stepping in the fronto-central cortical areas. Also, the MRPs and ERD prior to the onset of APA and onset of lateral weight shift were not significantly different suggesting the comparable cortical activations for the generation of postural and focal movements. The present study reveals the occurrence of cortical activation prior to the execution of an APA that precedes a step. Importantly, this cortical activity appears independent of the context of the movement.

  1. Astrocytes refine cortical connectivity at dendritic spines

    PubMed Central

    Risher, W Christopher; Patel, Sagar; Kim, Il Hwan; Uezu, Akiyoshi; Bhagat, Srishti; Wilton, Daniel K; Pilaz, Louis-Jan; Singh Alvarado, Jonnathan; Calhan, Osman Y; Silver, Debra L; Stevens, Beth; Calakos, Nicole; Soderling, Scott H; Eroglu, Cagla

    2014-01-01

    During cortical synaptic development, thalamic axons must establish synaptic connections despite the presence of the more abundant intracortical projections. How thalamocortical synapses are formed and maintained in this competitive environment is unknown. Here, we show that astrocyte-secreted protein hevin is required for normal thalamocortical synaptic connectivity in the mouse cortex. Absence of hevin results in a profound, long-lasting reduction in thalamocortical synapses accompanied by a transient increase in intracortical excitatory connections. Three-dimensional reconstructions of cortical neurons from serial section electron microscopy (ssEM) revealed that, during early postnatal development, dendritic spines often receive multiple excitatory inputs. Immuno-EM and confocal analyses revealed that majority of the spines with multiple excitatory contacts (SMECs) receive simultaneous thalamic and cortical inputs. Proportion of SMECs diminishes as the brain develops, but SMECs remain abundant in Hevin-null mice. These findings reveal that, through secretion of hevin, astrocytes control an important developmental synaptic refinement process at dendritic spines. DOI: http://dx.doi.org/10.7554/eLife.04047.001 PMID:25517933

  2. Sci-Hub: What Librarians Should Know and Do about Article Piracy.

    PubMed

    Hoy, Matthew B

    2017-01-01

    The high cost of journal articles has driven many researchers to turn to a new way of getting access: "pirate" article sites. Sci-Hub, the largest and best known of these sites, currently offers instant access to more than 58 million journal articles. Users attracted by the ease of use and breadth of the collection may not realize that these articles are often obtained using stolen credentials and downloading them may be illegal. This article will briefly describe Sci-Hub and how it works, the legal and ethical issues it raises, and the problems it may cause for librarians. Librarians should be aware of Sci-Hub and the ways it may change their patrons' expectations. They should also understand the risks Sci-Hub can pose to their patrons and their institutions.

  3. Empirical analysis on the human dynamics of blogging behavior on GitHub

    NASA Astrophysics Data System (ADS)

    Yan, Deng-Cheng; Wei, Zong-Wen; Han, Xiao-Pu; Wang, Bing-Hong

    2017-01-01

    GitHub is a social collaborative coding platform on which software developers not only collaborate on codes but also share knowledge through blogs using GitHub Pages. In this article, we analyze the blogging behavior of software developers on GitHub Pages. The results show that both the commit number and the inter-event time of two consecutive blogging actions follow heavy-tailed distribution. We further observe a significant variety of activity among individual developers, and a strongly positive correlation between the activity and the power-law exponent of the inter-event time distribution. We also find a difference between the user behaviors of GitHub Pages and other online systems which is driven by the diversity of users and length of contents. In addition, our result shows an obvious difference between the majority of developers and elite developers in their burstiness property.

  4. The hub wall boundary layer development and losses in an axial flow compressor rotor passage

    NASA Technical Reports Server (NTRS)

    Murthy, K. N. S.; Lakshminarayana, B.

    1987-01-01

    The hub wall boundary layer development in a compressor stage including the rotor passage is experimentally investigated. A miniature five-hole probe was employed to measure the hub wall boundary layer inside the inlet guide vane passage, upstream and far downstream of the rotor. The hub wall boundary layer inside the rotor passage was acquired using a rotating miniature five-hole probe. The boundary layer is well behaved upstream and far downstream of the rotor. The migration of the hub wall boundary layer towards the suction surface corner is observed. The limiting streamline angles and static pressure distribution across the stage were also measured. The mean velocity profiles and the integral properties upstream, inside and downstream of the rotor, and the losses are presented and interpreted.

  5. LSU network hubs integrate abiotic and biotic stress responses via interaction with the superoxide dismutase FSD2.

    PubMed

    Garcia-Molina, Antoni; Altmann, Melina; Alkofer, Angela; Epple, Petra M; Dangl, Jeffery L; Falter-Braun, Pascal

    2017-02-01

    In natural environments, plants often experience different stresses simultaneously, and adverse abiotic conditions can weaken the plant immune system. Interactome mapping revealed that the LOW SULPHUR UPREGULATED (LSU) proteins are hubs in an Arabidopsis protein interaction network that are targeted by virulence effectors from evolutionarily diverse pathogens. Here we show that LSU proteins are up-regulated in several abiotic and biotic stress conditions, such as nutrient depletion or salt stress, by both transcriptional and post-translational mechanisms. Interference with LSU expression prevents chloroplastic reactive oxygen species (ROS) production and proper stomatal closure during sulphur stress. We demonstrate that LSU1 interacts with the chloroplastic superoxide dismutase FSD2 and stimulates its enzymatic activity in vivo and in vitro. Pseudomonas syringae virulence effectors interfere with this interaction and preclude re-localization of LSU1 to chloroplasts. We demonstrate that reduced LSU levels cause a moderately enhanced disease susceptibility in plants exposed to abiotic stresses such as nutrient deficiency, high salinity, or heavy metal toxicity, whereas LSU1 overexpression confers significant disease resistance in several of these conditions. Our data suggest that the network hub LSU1 plays an important role in co-ordinating plant immune responses across a spectrum of abiotic stress conditions. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  6. Temporal retinal transcriptome and systems biology analysis identifies key pathways and hub genes in Staphylococcus aureus endophthalmitis.

    PubMed

    Rajamani, Deepa; Singh, Pawan Kumar; Rottmann, Bruce G; Singh, Natasha; Bhasin, Manoj K; Kumar, Ashok

    2016-02-11

    Bacterial endophthalmitis remains a devastating inflammatory condition associated with permanent vision loss. Hence, assessing the host response in this disease may provide new targets for intervention. Using a mouse model of Staphylococcus aureus (SA) endophthalmitis and performing retinal transcriptome analysis, we discovered progressive changes in the expression of 1,234 genes. Gene ontology (GO) and pathway analyses revealed the major pathways impacted in endophthalmitis includes: metabolism, inflammatory/immune, antimicrobial, cell trafficking, and lipid biosynthesis. Among the immune/inflammation pathways, JAK/Stat and IL-17A signaling were the most significantly affected. Interactive network-based analyses identified 13 focus hub genes (IL-6, IL-1β, CXCL2, STAT3, NUPR1, Jun, CSF1, CYR61, CEBPB, IGF-1, EGFR1, SPP1, and TGM2) within these important pathways. The expression of hub genes confirmed by qRT-PCR, ELISA (IL-6, IL-1β, and CXCL2), and Western blot or immunostaining (CEBP, STAT3, NUPR1, and IGF1) showed strong correlation with transcriptome data. Since TLR2 plays an important role in SA endophthalmitis, counter regulation analysis of TLR2 ligand pretreated retina or the use of retinas from TLR2 knockout mice showed the down-regulation of inflammatory regulatory genes. Collectively, our study provides, for the first time, a comprehensive analysis of the transcriptomic response and identifies key pathways regulating retinal innate responses in staphylococcal endophthalmitis.

  7. A genome-wide screen identifies conserved protein hubs required for cadherin-mediated cell–cell adhesion

    PubMed Central

    Toret, Christopher P.; D’Ambrosio, Michael V.; Vale, Ronald D.; Simon, Michael A.

    2014-01-01

    Cadherins and associated catenins provide an important structural interface between neighboring cells, the actin cytoskeleton, and intracellular signaling pathways in a variety of cell types throughout the Metazoa. However, the full inventory of the proteins and pathways required for cadherin-mediated adhesion has not been established. To this end, we completed a genome-wide (∼14,000 genes) ribonucleic acid interference (RNAi) screen that targeted Ca2+-dependent adhesion in DE-cadherin–expressing Drosophila melanogaster S2 cells in suspension culture. This novel screen eliminated Ca2+-independent cell–cell adhesion, integrin-based adhesion, cell spreading, and cell migration. We identified 17 interconnected regulatory hubs, based on protein functions and protein–protein interactions that regulate the levels of the core cadherin–catenin complex and coordinate cadherin-mediated cell–cell adhesion. Representative proteins from these hubs were analyzed further in Drosophila oogenesis, using targeted germline RNAi, and adhesion was analyzed in Madin–Darby canine kidney mammalian epithelial cell–cell adhesion. These experiments reveal roles for a diversity of cellular pathways that are required for cadherin function in Metazoa, including cytoskeleton organization, cell–substrate interactions, and nuclear and cytoplasmic signaling. PMID:24446484

  8. Airlift Cargo Hub Port Hold Times: Controlling Variations in Defense Supply Chain Delivery

    DTIC Science & Technology

    2010-06-01

    Pagh, 1997). Finally, SCM seeks to establish a flow of goods and information across the chain in order to generate system efficiencies. By...efficiently as possible. High system demand, limited cargo capacity, and desired cost efficiencies drive significant portions of even the highest...priority wartime cargo into a hub and spoke delivery system . However, additional efficiencies afforded through hub and spoke delivery come at the

  9. A Software Hub for High Assurance Model-Driven Development and Analysis

    DTIC Science & Technology

    2007-01-23

    SAL input notation for the SALSA analysis tool, and several experiments conducted that demonstrated the utility of applying SALSA -style analyses to...widely used Simulink / Stateflow notation of The MathWorks into the SCR Abstract Language (SAL), the input notation of the Salsa [BS00] invariant...output with Salsa indicates that the appropriately designed hub and hub language and might facilitate much greater tool interoperability than currently

  10. The hub-and-spoke organization design: an avenue for serving patients well.

    PubMed

    Elrod, James K; Fortenberry, John L

    2017-07-11

    The healthcare industry is characterized by intensive, never-ending change occurring on a multitude of fronts. Success in such tumultuous environments requires healthcare providers to be proficient in myriad areas, including the manner in which they organize and deliver services. Less efficient designs drain precious resources and hamper efforts to deliver the best care possible to patients, making it imperative that optimal pathways are identified and pursued. One particular avenue that offers great potential for serving patients efficiently and effectively is known as the hub-and-spoke organization design. The hub-and-spoke organization design is a model which arranges service delivery assets into a network consisting of an anchor establishment (hub) which offers a full array of services, complemented by secondary establishments (spokes) which offer more limited service arrays, routing patients needing more intensive services to the hub for treatment. Hub-and-spoke networks afford many benefits for healthcare providers, but in order to capitalize fully, proper assembly is required. To advance awareness, knowledge, and use of the hub-and-spoke organization design, this article profiles Willis-Knighton Health System's service delivery network which has utilized the model for over three decades. Among other things, the hub-and-spoke organization design is defined, benefits are stipulated, and applications are discussed, permitting healthcare providers essential insights for the establishment and operation of these networks. The change-rich nature of the healthcare industry places a premium on incorporating advancements that permit health and medical providers to operate as optimally as possible. The hub-and-spoke organization design represents an option that, when deployed correctly, can greatly assist healthcare establishments in their quests to serve patients well.

  11. A Dynamic Calibration Method for Experimental and Analytical Hub Load Comparison

    DTIC Science & Technology

    2017-03-01

    Dynamics Tunnel (TDT). A frequency-dependent transformation between loads at the rotor hub and outputs of the testbed balance is produced from...frequency response functions measured during vibration testing of the system. The resulting transformation is used as a dynamic calibration of the balance ...to transform hub loads predicted by comprehensive analysis into predicted balance outputs. In addition to detailing the transformation process, this

  12. Cortical Stimulation Concurrent With Skilled Motor Training Improves Forelimb Function and Enhances Motor Cortical Reorganization Following Controlled Cortical Impact.

    PubMed

    Jefferson, Stephanie C; Clayton, Elyse Renee; Donlan, Nicole A; Kozlowski, Dorothy Annette; Jones, Theresa A; Adkins, DeAnna Lynn

    2016-02-01

    Electrical and magnetic brain stimulation can improve motor function following stroke in humans, rats, and nonhuman primates, especially when paired with rehabilitative training (RT). Previously, we found in rodent stroke models that epidural electrical cortical stimulation (CS) of the ipsilesional motor cortex (MC) combined with motor RT enhances motor function and motor cortical plasticity. It was unknown whether CS following experimental traumatic brain injury (TBI) would have similar effects. To test the effects of CS combined with motor training after moderate/severe TBI on behavioral outcome and motor cortical organization. Following unilateral controlled cortical impact (CCI) over the caudal forelimb area of the MC in adult male rats, forelimb reach training was administered daily for 9 weeks concurrently with subthreshold, 100-Hz monopolar CS or no-stimulation control procedures. The rate and magnitude of behavioral improvements and changes in forelimb movement representations in the injured MC as revealed by intracortical microstimulation were measured. CCI resulted in severe motor impairments persisting throughout the 9 weeks of training in both groups, but CS-treated animals had significantly greater behavioral improvements. CS also increased wrist motor cortical representation, one of the main movements used in the training task, when compared with RT alone. However, the overall recovery level was modest, leaving animals still extremely impaired. These data suggest that CS may be useful for improving rehabilitation efficacy after TBI but also raise the possibility that the CS parameters that are highly effective following stroke are suboptimal after moderate/severe TBI. © The Author(s) 2015.

  13. Experimental investigation of advanced hub and pylon fairing configurations to reduce helicopter drag

    NASA Technical Reports Server (NTRS)

    Martin, D. M.; Mort, R. W.; Young, L. A.; Squires, P. K.

    1993-01-01

    New hub and pylon fairing designs were tested on a one-fifth scale Bell Helicopter Textron Model 222 helicopter with a bearingless main rotor hub. The blades were not installed for this test. The fairings were designed by NASA and Bell Helicopter Textron under a joint program and tested in the Ames Research Center 7-by 10-Foot Wind Tunnel. All six aircraft forces and moments were measured using the tunnel scales system. Previous research has identified the integrated hub and pylon fairing approach as the most efficient in reducing helicopter drag. Three hub fairings and three pylon fairings were tested (in various combinations) resulting in a total of 16 different configurations, including the baseline helicopter model without fairings. The geometry of the new fairings is described in detail. Test results are presented in the form of plots of the six model forces and moments. The data show that model drag can be reduced by as much as 20 percent by combining a small hub fairing (that has a circular arc upper surface and a flat lower surface) integrated with a nontapered pylon fairing. To minimize drag, the gap between the lower surface of the hub and upper surface of the pylon fairing must be kept to a minimum. Results show that the aerodynamic effects of the fairings on static longitudinal and directional stability can also be important.

  14. Design and Analysis of Wind Turbine Blade Hub using Aluminium Alloy AA 6061-T6

    NASA Astrophysics Data System (ADS)

    Ravikumar, S.; Jaswanthvenkatram, V.; Sai kumar, Y. J. N. V.; Sohaib, S. Md.

    2017-05-01

    This work presents the design and analysis of horizontal axis wind turbine blade hub using different material. The hub is very crucial part of the wind turbine, which experience the loads from the blades and the loads were transmitted to the main shaft. At present wind turbine is more expensive and weights more than a million pounds, with the nacelle, rotor hub and blades accounting for most of the weight. In this work Spheroidal graphite cast iron GGG 40.3 is replaced by aluminium alloy 6061-T6 to enhance the casting properties and also to improve the strength-weight ratio. This transition of material leads to reduction in weight of the wind turbine. All the loads caused by wind and extreme loads on the blades are transferred to the hub. Considering the IEC 61400-1 standard for defining extreme loads on the hub the stress and deflection were calculated on the hub by using Finite element Analysis. Result obtained from ANSYS is compared and discussed with the existing design.

  15. In vitro bacteriological study of a new hub model for intravascular catheters and infusion equipment.

    PubMed Central

    Segura, M; Alía, C; Oms, L; Sancho, J J; Torres-Rodríguez, J M; Sitges-Serra, A

    1989-01-01

    We investigated in vitro the antibacterial properties of a simulated new hub model in which the female part has an antiseptic chamber through which the needle (male part) must pass before connection of the set and the catheter. To establish the time needed for disinfection, the magnitude of reduction of the contaminating inocula by the new hub model, and the antibacterial properties of the different components of the hub, we used needles contaminated with solutions containing high inocula (1.9 x 10(7) to 1.2 x 10(11) CFU/ml) of microorganisms involved in hub-related catheter sepsis. Sterilization of the needles was accomplished by allowing them to remain in the antiseptic chamber for 10 s in all assays with Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. The rubber closures limiting the antiseptic chamber and the dilution effect of the antiseptic itself accounted for a minor part of the inoculum reduction achieved by the new hub model. This simulated hub provides good protection against endoluminal contamination. Further studies seem warranted to prove its industrial viability and clinical efficacy. PMID:2512322

  16. Comparative efficiency of wind turbines with different heights of rotor hubs: performance evaluation for Latvia

    NASA Astrophysics Data System (ADS)

    Bezrukovs, V. P.; Bezrukovs, V. V.; Zacepins, A. J.

    2014-06-01

    Performance evaluation of wind turbines (WT) for different heights of the rotor hub is made based on the wind speed and direction data obtained in 2009-2013 on-shore in the north of Latvia using a LOGGER 9200 Symphonie measurement system mounted on a 60 m mast. Based on the measurement analysis results, wind speed distribution curves have been modelled for heights of up to 200 m using power and logarithmic (log) law approximation methods. The curves for the modelled Weibull's parameters are plotted in dependence on height. The efficiency comparison is made for different WT types taking into account the distribution of the wind energy potential in height in the Latvian territory. The annual electric energy production was calculated for the WTs with different heights of rotor hubs. In the calculations the technical data on the following WT types were used: E-3120 (50 kW, hub height 20.5/30.5/36.5/42.7 m), E-33 (330 kW, hub height 37/44/49/50 m), E-48 (800 kW, hub height 50/60/75 m) and E-82 (2.3 MW, hub height of 78/85/98/108/138 m).

  17. AIRE-PHD fingers are structural hubs to maintain the integrity of chromatin-associated interactome

    PubMed Central

    Gaetani, Massimiliano; Matafora, Vittoria; Saare, Mario; Spiliotopoulos, Dimitrios; Mollica, Luca; Quilici, Giacomo; Chignola, Francesca; Mannella, Valeria; Zucchelli, Chiara; Peterson, Pärt; Bachi, Angela; Musco, Giovanna

    2012-01-01

    Mutations in autoimmune regulator (AIRE) gene cause autoimmune polyendocrinopathy candidiasis ectodermal dystrophy. AIRE is expressed in thymic medullary epithelial cells, where it promotes the expression of peripheral-tissue antigens to mediate deletional tolerance, thereby preventing self-reactivity. AIRE contains two plant homeodomains (PHDs) which are sites of pathological mutations. AIRE-PHD fingers are important for AIRE transcriptional activity and presumably play a crucial role in the formation of multimeric protein complexes at chromatin level which ultimately control immunological tolerance. As a step forward the understanding of AIRE-PHD fingers in normal and pathological conditions, we investigated their structure and used a proteomic SILAC approach to assess the impact of patient mutations targeting AIRE-PHD fingers. Importantly, both AIRE-PHD fingers are structurally independent and mutually non-interacting domains. In contrast to D297A and V301M on AIRE-PHD1, the C446G mutation on AIRE-PHD2 destroys the structural fold, thus causing aberrant AIRE localization and reduction of AIRE target genes activation. Moreover, mutations targeting AIRE-PHD1 affect the formation of a multimeric protein complex at chromatin level. Overall our results reveal the importance of AIRE-PHD domains in the interaction with chromatin-associated nuclear partners and gene regulation confirming the role of PHD fingers as versatile protein interaction hubs for multiple binding events. PMID:23074189

  18. The G Protein-Coupled Receptor Heterodimer Network (GPCR-HetNet) and Its Hub Components

    PubMed Central

    Borroto-Escuela, Dasiel O.; Brito, Ismel; Romero-Fernandez, Wilber; Di Palma, Michael; Oflijan, Julia; Skieterska, Kamila; Duchou, Jolien; Van Craenenbroeck, Kathleen; Suárez-Boomgaard, Diana; Rivera, Alicia; Guidolin, Diego; Agnati, Luigi F.; Fuxe, Kjell

    2014-01-01

    G protein-coupled receptors (GPCRs) oligomerization has emerged as a vital characteristic of receptor structure. Substantial experimental evidence supports the existence of GPCR-GPCR interactions in a coordinated and cooperative manner. However, despite the current development of experimental techniques for large-scale detection of GPCR heteromers, in order to understand their connectivity it is necessary to develop novel tools to study the global heteroreceptor networks. To provide insight into the overall topology of the GPCR heteromers and identify key players, a collective interaction network was constructed. Experimental interaction data for each of the individual human GPCR protomers was obtained manually from the STRING and SCOPUS databases. The interaction data were used to build and analyze the network using Cytoscape software. The network was treated as undirected throughout the study. It is comprised of 156 nodes, 260 edges and has a scale-free topology. Connectivity analysis reveals a significant dominance of intrafamily versus interfamily connections. Most of the receptors within the network are linked to each other by a small number of edges. DRD2, OPRM, ADRB2, AA2AR, AA1R, OPRK, OPRD and GHSR are identified as hubs. In a network representation 10 modules/clusters also appear as a highly interconnected group of nodes. Information on this GPCR network can improve our understanding of molecular integration. GPCR-HetNet has been implemented in Java and is freely available at http://www.iiia.csic.es/~ismel/GPCR-Nets/index.html. PMID:24830558

  19. The G protein-coupled receptor heterodimer network (GPCR-HetNet) and its hub components.

    PubMed

    Borroto-Escuela, Dasiel O; Brito, Ismel; Romero-Fernandez, Wilber; Di Palma, Michael; Oflijan, Julia; Skieterska, Kamila; Duchou, Jolien; Van Craenenbroeck, Kathleen; Suárez-Boomgaard, Diana; Rivera, Alicia; Guidolin, Diego; Agnati, Luigi F; Fuxe, Kjell

    2014-05-14

    G protein-coupled receptors (GPCRs) oligomerization has emerged as a vital characteristic of receptor structure. Substantial experimental evidence supports the existence of GPCR-GPCR interactions in a coordinated and cooperative manner. However, despite the current development of experimental techniques for large-scale detection of GPCR heteromers, in order to understand their connectivity it is necessary to develop novel tools to study the global heteroreceptor networks. To provide insight into the overall topology of the GPCR heteromers and identify key players, a collective interaction network was constructed. Experimental interaction data for each of the individual human GPCR protomers was obtained manually from the STRING and SCOPUS databases. The interaction data were used to build and analyze the network using Cytoscape software. The network was treated as undirected throughout the study. It is comprised of 156 nodes, 260 edges and has a scale-free topology. Connectivity analysis reveals a significant dominance of intrafamily versus interfamily connections. Most of the receptors within the network are linked to each other by a small number of edges. DRD2, OPRM, ADRB2, AA2AR, AA1R, OPRK, OPRD and GHSR are identified as hubs. In a network representation 10 modules/clusters also appear as a highly interconnected group of nodes. Information on this GPCR network can improve our understanding of molecular integration. GPCR-HetNet has been implemented in Java and is freely available at http://www.iiia.csic.es/~ismel/GPCR-Nets/index.html.

  20. nArgBP2 as a hub molecule in the etiology of various neuropsychiatric disorders

    PubMed Central

    Lee, Sang-Eun; Chang, Sunghoe

    2016-01-01

    Recent studies have strongly implicated postsynaptic scaffolding proteins such as SAPAP3 or Shank3 in the pathogenesis of various mood disorders, including autism spectrum disorder, bipolar disorder (BD), and obsessive-compulsive disorders. Neural Abelson-related gene-binding protein 2 (nArgBP2) was originally identified as a protein that interacts with SAPAP3 and Shank3. Recent study shows that the genetic deletion of nArgBP2 in mice leads to manic/bipolar-like behavior resembling symptoms of BD. However, the function of nArgBP2 at synapse, or its connection with the synaptic dysfunctions, is completely unknown. This study provides compelling evidence that nArgBP2 regulates the spine morphogenesis through the activation of Rac1/WAVE/PAK/cofilin pathway, and that its ablation causes a robust and selective inhibition of excitatory synapse formation, by controlling actin dynamics. Our results revealed the underlying mechanism for the synaptic dysfunction caused by nArgBP2 downregulation that associates with analogous human BD. Moreover, since nArgBP2 interacts with key proteins involved in various neuropsychiatric disorders, our finding implies that nArgBP2 could function as a hub linking various etiological factors of different mood disorders. [BMB Reports 2016; 49(9): 457-458] PMID:27530683

  1. AIRE-PHD fingers are structural hubs to maintain the integrity of chromatin-associated interactome.

    PubMed

    Gaetani, Massimiliano; Matafora, Vittoria; Saare, Mario; Spiliotopoulos, Dimitrios; Mollica, Luca; Quilici, Giacomo; Chignola, Francesca; Mannella, Valeria; Zucchelli, Chiara; Peterson, Pärt; Bachi, Angela; Musco, Giovanna

    2012-12-01

    Mutations in autoimmune regulator (AIRE) gene cause autoimmune polyendocrinopathy candidiasis ectodermal dystrophy. AIRE is expressed in thymic medullary epithelial cells, where it promotes the expression of peripheral-tissue antigens to mediate deletional tolerance, thereby preventing self-reactivity. AIRE contains two plant homeodomains (PHDs) which are sites of pathological mutations. AIRE-PHD fingers are important for AIRE transcriptional activity and presumably play a crucial role in the formation of multimeric protein complexes at chromatin level which ultimately control immunological tolerance. As a step forward the understanding of AIRE-PHD fingers in normal and pathological conditions, we investigated their structure and used a proteomic SILAC approach to assess the impact of patient mutations targeting AIRE-PHD fingers. Importantly, both AIRE-PHD fingers are structurally independent and mutually non-interacting domains. In contrast to D297A and V301M on AIRE-PHD1, the C446G mutation on AIRE-PHD2 destroys the structural fold, thus causing aberrant AIRE localization and reduction of AIRE target genes activation. Moreover, mutations targeting AIRE-PHD1 affect the formation of a multimeric protein complex at chromatin level. Overall our results reveal the importance of AIRE-PHD domains in the interaction with chromatin-associated nuclear partners and gene regulation confirming the role of PHD fingers as versatile protein interaction hubs for multiple binding events.

  2. NGC 281: A Bustling Hub of Star Formation

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NGC 281 is a bustling hub of star formation about 10,000 light years away. This composite image of optical and X-ray emission includes regions where new stars are forming and older regions containing stars about 3 million years old. The optical data (seen in red, orange, and yellow) show a small open cluster of stars, large lanes of obscuring gas and dust, and dense knots where stars may still be forming. The X-ray data (purple), based on a Chandra observation lasting more than a day, shows a different view. More than 300 individual X-ray sources are seen, most of them associated with IC 1590, the central cluster. The edge-on aspect of NGC 281 allows scientists to study the effects of powerful X-rays on the gas in the region, the raw material for star formation. A second group of X-ray sources is seen on either side of a dense molecular cloud, known as NGC 281 West, a cool cloud of dust grains and gas, much of which is in the form of molecules. The bulk of the sources around the molecular cloud are coincident with emission from polycyclic aromatic hydrocarbons, a family of organic molecules containing carbon and hydrogen. There also appears to be cool diffuse gas associated with IC 1590 that extends toward NGC 281 West. The X-ray spectrum of this region shows that the gas is a few million degrees and contains significant amounts of magnesium, sulfur and silicon. The presence of these elements suggests that supernova recently went off in that area.

  3. Testing and Life Prediction for Composite Rotor Hub Flexbeams

    NASA Technical Reports Server (NTRS)

    Murri, Gretchen B.

    2004-01-01

    A summary of several studies of delamination in tapered composite laminates with internal ply-drops is presented. Initial studies used 2D FE models to calculate interlaminar stresses at the ply-ending locations in linear tapered laminates under tension loading. Strain energy release rates for delamination in these laminates indicated that delamination would likely start at the juncture of the tapered and thin regions and grow unstably in both directions. Tests of glass/epoxy and graphite/epoxy linear tapered laminates under axial tension delaminated as predicted. Nonlinear tapered specimens were cut from a full-size helicopter rotor hub and were tested under combined constant axial tension and cyclic transverse bending loading to simulate the loading experienced by a rotorhub flexbeam in flight. For all the tested specimens, delamination began at the tip of the outermost dropped ply group and grew first toward the tapered region. A 2D FE model was created that duplicated the test flexbeam layup, geometry, and loading. Surface strains calculated by the model agreed very closely with the measured surface strains in the specimens. The delamination patterns observed in the tests were simulated in the model by releasing pairs of MPCs along those interfaces. Strain energy release rates associated with the delamination growth were calculated for several configurations and using two different FE analysis codes. Calculations from the codes agreed very closely. The strain energy release rate results were used with material characterization data to predict fatigue delamination onset lives for nonlinear tapered flexbeams with two different ply-dropping schemes. The predicted curves agreed well with the test data for each case studied.

  4. A novel virtual hub approach for multisource downstream service integration

    NASA Astrophysics Data System (ADS)

    Previtali, Mattia; Cuca, Branka; Barazzetti, Luigi

    2016-08-01

    A large development of downstream services is expected to be stimulated starting from earth observations (EO) datasets acquired by Copernicus satellites. An important challenge connected with the availability of downstream services is the possibility for their integration in order to create innovative applications with added values for users of different categories level. At the moment, the world of geo-information (GI) is extremely heterogeneous in terms of standards and formats used, thus preventing a facilitated access and integration of downstream services. Indeed, different users and data providers have also different requirements in terms of communication protocols and technology advancement. In recent years, many important programs and initiatives have tried to address this issue even on trans-regional and international level (e.g. INSPIRE Directive, GEOSS, Eye on Earth and SEIS). However, a lack of interoperability between systems and services still exists. In order to facilitate the interaction between different downstream services, a new architectural approach (developed within the European project ENERGIC OD) is proposed in this paper. The brokering-oriented architecture introduces a new mediation layer (the Virtual Hub) which works as an intermediary to bridge the gaps linked to interoperability issues. This intermediation layer de-couples the server and the client allowing a facilitated access to multiple downstream services and also Open Data provided by national and local SDIs. In particular, in this paper an application is presented integrating four services on the topic of agriculture: (i) the service given by Space4Agri (providing services based on MODIS and Landsat data); (ii) Gicarus Lab (providing sample services based on Landsat datasets) and (iii) FRESHMON (providing sample services for water quality) and services from a several regional SDIs.

  5. Cortical commands in active touch.

    PubMed

    Brecht, Michael

    2006-01-01

    The neocortex is an enormous network of extensively interconnected neurons. It has become clear that the computations performed by individual cortical neurons will critically depend on the quantitative composition of cortical activity. Here we discuss quantitative aspects of cortical activity and modes of cortical processing in the context of rodent active touch. Through in vivo whole-cell recordings one observes widespread subthreshold and very sparse evoked action potential (AP) activity in the somatosensory cortex both for passive whisker deflection in anaesthetized animals and during active whisker movements in awake animals. Neurons of the somatosensory cortex become either suppressed during whisking or activated by an efference copy of whisker movement signal that depolarize cells at certain phases of the whisking cycle. To probe the read out of cortical motor commands we applied intracellular stimulation in rat whisker motor cortex. We find that APs in individual cortical neurons can evoke long sequences of small whisker movements. The capacity of an individual neuron to evoke movements is most astonishing given the large number of neurons in whisker motor cortex. Thus, few cortical APs may suffice to control motor behaviour and such APs can be translated into action with the utmost precision. We conclude that there is very widespread subthreshold cortical activity and very sparse, highly specific cortical AP activity.

  6. Transcriptomic network analyses of leaf dehydration responses identify highly connected ABA and ethylene signaling hubs in three grapevine species differing in drought tolerance.

    PubMed

    Hopper, Daniel W; Ghan, Ryan; Schlauch, Karen A; Cramer, Grant R

    2016-05-23

    Grapevine is a major food crop that is affected by global climate change. Consistent with field studies, dehydration assays of grapevine leaves can reveal valuable information of the plant's response at physiological, transcript, and protein levels. There are well-known differences in grapevine rootstocks responses to dehydration. We used time-series transcriptomic approaches combined with network analyses to elucidate and identify important physiological processes and network hubs that responded to dehydration in three different grapevine species differing in their drought tolerance. Transcriptomic analyses of the leaves of Cabernet Sauvignon, Riparia Gloire, and Ramsey were evaluated at different times during a 24-h controlled dehydration. Analysis of variance (ANOVA) revealed that approximately 11,000 transcripts changed significantly with respect to the genotype x treatment interaction term and approximately 6000 transcripts changed significantly according to the genotype x treatment x time interaction term indicating massive differential changes in gene expression over time. Standard analyses determined substantial effects on the transcript abundance of genes involved in the metabolism and signaling of two known plant stress hormones, abscisic acid (ABA) and ethylene. ABA and ethylene signaling maps were constructed and revealed specific changes in transcript abundance that were associated with the known drought tolerance of the genotypes including genes such as VviABI5, VviABF2, VviACS2, and VviWRKY22. Weighted-gene coexpression network analysis (WGCNA) confirmed these results. In particular, WGCNA identified 30 different modules, some of which had highly enriched gene ontology (GO) categories for photosynthesis, phenylpropanoid metabolism, ABA and ethylene signaling. The ABA signaling transcription factors, VviABI5 and VviABF2, were highly connected hubs in two modules, one being enriched in gaseous transport and the other in ethylene signaling. VviABI5 was

  7. Self-organized criticality in cortical assemblies occurs in concurrent scale-free and small-world networks

    PubMed Central

    Massobrio, Paolo; Pasquale, Valentina; Martinoia, Sergio

    2015-01-01

    The spontaneous activity of cortical networks is characterized by the emergence of different dynamic states. Although several attempts were accomplished to understand the origin of these dynamics, the underlying factors continue to be elusive. In this work, we specifically investigated the interplay between network topology and spontaneous dynamics within the framework of self-organized criticality (SOC). The obtained results support the hypothesis that the emergence of critical states occurs in specific complex network topologies. By combining multi-electrode recordings of spontaneous activity of in vitro cortical assemblies with theoretical models, we demonstrate that different ‘connectivity rules’ drive the network towards different dynamic states. In particular, scale-free architectures with different degree of small-worldness account better for the variability observed in experimental data, giving rise to different dynamic states. Moreover, in relationship with the balance between excitation and inhibition and percentage of inhibitory hubs, the simulated cortical networks fall in a critical regime. PMID:26030608

  8. Self-organized criticality in cortical assemblies occurs in concurrent scale-free and small-world networks.

    PubMed

    Massobrio, Paolo; Pasquale, Valentina; Martinoia, Sergio

    2015-06-01

    The spontaneous activity of cortical networks is characterized by the emergence of different dynamic states. Although several attempts were accomplished to understand the origin of these dynamics, the underlying factors continue to be elusive. In this work, we specifically investigated the interplay between network topology and spontaneous dynamics within the framework of self-organized criticality (SOC). The obtained results support the hypothesis that the emergence of critical states occurs in specific complex network topologies. By combining multi-electrode recordings of spontaneous activity of in vitro cortical assemblies with theoretical models, we demonstrate that different 'connectivity rules' drive the network towards different dynamic states. In particular, scale-free architectures with different degree of small-worldness account better for the variability observed in experimental data, giving rise to different dynamic states. Moreover, in relationship with the balance between excitation and inhibition and percentage of inhibitory hubs, the simulated cortical networks fall in a critical regime.

  9. Cortical-Cortical Interactions And Sensory Information Processing in Autism

    DTIC Science & Technology

    2008-04-30

    Additionally, these cortical areas have been implicated from significantly elevated TOJ thresholds (worse performance) in subjects with dyslexia [5...of the fact that above-average TOJ thresholds occur in subjects with known damage to these same cortical areas ( dyslexia [5], dystonia [6-8], and

  10. New hierarchical classification of food items for the assessment of exposure to packaging migrants: use of hub codes for different food groups.

    PubMed

    Northing, P; Oldring, P K T; Castle, L; Mason, P A S S

    2009-04-01

    This paper describes development work undertaken to expand the capabilities of an existing two-dimensional probabilistic modelling approach for assessing dietary exposure to chemicals migrating out of food contact materials. A new three-level hub-coding system has been devised for coding different food groups with regards to their consumption by individuals. The hub codes can be used at three different levels representing a high, medium and low level of aggregation of individual food items. The hub codes were developed because they have a greater relevance to packaging migration than coding used (largely and historically) for nutritional purposes. Also, the hub codes will assist pan-europeanization of the exposure model in the future, when up to 27 or more different food coding systems from 27 European Union Member States will have to be assimilated into the modelling approach. The applicability of the model with the new coding system has been tested by incorporating newly released 2001 UK consumption data. The example used was exposure to a hypothetical migrant from coated metal packaging for foodstuffs. When working at the three hierarchical levels, it was found that the tiered approach gave conservative estimates at the cruder level of refinement and a more realistic assessment was obtained as the refinement progressed. The work overall revealed that changes in eating habits over time had a relatively small impact on estimates of exposure. More important impacts are changes over time in packaging usage, packaging composition and migration levels. For countries like the UK, which has sophisticated food consumption data, it is uncertainties in these other areas that need to be addressed by new data collection.

  11. Identification of a brainstem circuit regulating visual cortical state in parallel with locomotion.

    PubMed

    Lee, A Moses; Hoy, Jennifer L; Bonci, Antonello; Wilbrecht, Linda; Stryker, Michael P; Niell, Cristopher M

    2014-07-16

    Sensory processing is dependent upon behavioral state. In mice, locomotion is accompanied by changes in cortical state and enhanced visual responses. Although recent studies have begun to elucidate intrinsic cortical mechanisms underlying this effect, the neural circuits that initially couple locomotion to cortical processing are unknown. The mesencephalic locomotor region (MLR) has been shown to be capable of initiating running and is associated with the ascending reticular activating system. Here, we find that optogenetic stimulation of the MLR in awake, head-fixed mice can induce both locomotion and increases in the gain of cortical responses. MLR stimulation below the threshold for overt movement similarly changed cortical processing, revealing that MLR's effects on cortex are dissociable from locomotion. Likewise, stimulation of MLR projections to the basal forebrain also enhanced cortical responses, suggesting a pathway linking the MLR to cortex. These studies demonstrate that the MLR regulates cortical state in parallel with locomotion. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Mapping cortical mesoscopic networks of single spiking cortical or sub-cortical neurons

    PubMed Central

    Xiao, Dongsheng; Vanni, Matthieu P; Mitelut, Catalin C; Chan, Allen W; LeDue, Jeffrey M; Xie, Yicheng; Chen, Andrew CN; Swindale, Nicholas V; Murphy, Timothy H

    2017-01-01

    Understanding the basis of brain function requires knowledge of cortical operations over wide-spatial scales, but also within the context of single neurons. In vivo, wide-field GCaMP imaging and sub-cortical/cortical cellular electrophysiology were used in mice to investigate relationships between spontaneous single neuron spiking and mesoscopic cortical activity. We make use of a rich set of cortical activity motifs that are present in spontaneous activity in anesthetized and awake animals. A mesoscale spike-triggered averaging procedure allowed the identification of motifs that are preferentially linked to individual spiking neurons by employing genetically targeted indicators of neuronal activity. Thalamic neurons predicted and reported specific cycles of wide-scale cortical inhibition/excitation. In contrast, spike-triggered maps derived from single cortical neurons yielded spatio-temporal maps expected for regional cortical consensus function. This approach can define network relationships between any point source of neuronal spiking and mesoscale cortical maps. DOI: http://dx.doi.org/10.7554/eLife.19976.001 PMID:28160463

  13. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy

    PubMed Central

    Kaski, Diego; Yong, Keir X. X.; Paterson, Ross W.; Slattery, Catherine F.; Ryan, Natalie S.; Schott, Jonathan M.; Crutch, Sebastian J.

    2015-01-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal ‘visual dementia’ and most common atypical Alzheimer’s disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients’ (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer’s disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer’s disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer’s disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with ‘sticky fixation’. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer’s disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large

  14. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

    PubMed

    Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

    2015-07-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer's disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer's disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with 'sticky fixation'. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer's disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large saccadic intrusions

  15. Disrupted Nodal and Hub Organization Account for Brain Network Abnormalities in Parkinson’s Disease

    PubMed Central

    Koshimori, Yuko; Cho, Sang-Soo; Criaud, Marion; Christopher, Leigh; Jacobs, Mark; Ghadery, Christine; Coakeley, Sarah; Harris, Madeleine; Mizrahi, Romina; Hamani, Clement; Lang, Anthony E.; Houle, Sylvain; Strafella, Antonio P.

    2016-01-01

    The recent application of graph theory to brain networks promises to shed light on complex diseases such as Parkinson’s disease (PD). This study aimed to investigate functional changes in sensorimotor and cognitive networks in Parkinsonian patients, with a focus on inter- and intra-connectivity organization in the disease-associated nodal and hub regions using the graph theoretical analyses. Resting-state functional MRI data of a total of 65 participants, including 23 healthy controls (HCs) and 42 patients, were investigated in 120 nodes for local efficiency, betweenness centrality, and degree. Hub regions were identified in the HC and patient groups. We found nodal and hub changes in patients compared with HCs, including the right pre-supplementary motor area (SMA), left anterior insula, bilateral mid-insula, bilateral dorsolateral prefrontal cortex (DLPFC), and right caudate nucleus. In general, nodal regions within the sensorimotor network (i.e., right pre-SMA and right mid-insula) displayed weakened connectivity, with the former node associated with more severe bradykinesia, and impaired integration with default mode network regions. The left mid-insula also lost its hub properties in patients. Within the executive networks, the left anterior insular cortex lost its hub properties in patients, while a new hub region was identified in the right caudate nucleus, paralleled by an increased level of inter- and intra-connectivity in the bilateral DLPFC possibly representing compensatory mechanisms. These findings highlight the diffuse changes in nodal organization and regional hub disruption accounting for the distributed abnormalities across brain networks and the clinical manifestations of PD. PMID:27891090

  16. Censoring Distances Based on Labeled Cortical Distance Maps in Cortical Morphometry

    PubMed Central

    Ceyhan, Elvan; Nishino, Tomoyuki; Alexopolous, Dimitrios; Todd, Richard D.; Botteron, Kelly N.; Miller, Michael I.; Ratnanather, J. Tilak

    2013-01-01

    It has been demonstrated that shape differences in cortical structures may be manifested in neuropsychiatric disorders. Such morphometric differences can be measured by labeled cortical distance mapping (LCDM) which characterizes the morphometry of the laminar cortical mantle of cortical structures. LCDM data consist of signed/labeled distances of gray matter (GM) voxels with respect to GM/white matter (WM) surface. Volumes and other summary measures for each subject and the pooled distances can help determine the morphometric differences between diagnostic groups, however they do not reveal all the morphometric information contained in LCDM distances. To extract more information from LCDM data, censoring of the pooled distances is introduced for each diagnostic group where the range of LCDM distances is partitioned at a fixed increment size; and at each censoring step, the distances not exceeding the censoring distance are kept. Censored LCDM distances inherit the advantages of the pooled distances but also provide information about the location of morphometric differences which cannot be obtained from the pooled distances. However, at each step, the censored distances aggregate, which might confound the results. The influence of data aggregation is investigated with an extensive Monte Carlo simulation analysis and it is demonstrated that this influence is negligible. As an illustrative example, GM of ventral medial prefrontal cortices (VMPFCs) of subjects with major depressive disorder (MDD), subjects at high risk (HR) of MDD, and healthy control (Ctrl) subjects are used. A significant reduction in laminar thickness of the VMPFC in MDD and HR subjects is observed compared to Ctrl subjects. Moreover, the GM LCDM distances (i.e., locations with respect to the GM/WM surface) for which these differences start to occur are determined. The methodology is also applicable to LCDM-based morphometric measures of other cortical structures affected by disease. PMID:24133482

  17. Learning strategy determines auditory cortical plasticity

    PubMed Central

    Berlau, Kasia M.; Weinberger, Norman M.

    2013-01-01

    Learning modifies the primary auditory cortex (A1) to emphasize the processing and representation of behaviorally relevant sounds. However, the factors that determine cortical plasticity are poorly understood. While the type and amount of learning are assumed to be important, the actual strategies used to solve learning problems might be critical. To investigate this possibility, we trained two groups of adult male Sprague–Dawley rats to bar-press (BP) for water contingent on the presence of a 5.0 kHz tone using two different strategies: BP during tone presence or BP from tone-onset until receiving an error signal after tone cessation. Both groups achieved the same high levels of correct performance and both groups revealed equivalent learning of absolute frequency during training. Post-training terminal “mapping” of A1 showed no change in representational area of the tone signal frequency but revealed other substantial cue-specific plasticity that developed only in the tone-onset-to-error strategy group. Threshold was decreased ~10 dB and tuning bandwidth was narrowed by ~0.7 octaves. As sound onsets have greater perceptual weighting and cortical discharge efficacy than continual sound presence, the induction of specific learning-induced cortical plasticity may depend on the use of learning strategies that best exploit cortical proclivities. The present results also suggest a general principle for the induction and storage of plasticity in learning, viz., that the representation of specific acquired information may be selected by neurons according to a match between behaviorally selected stimulus features and circuit/network response properties. PMID:17707663

  18. Evaluating mandibular cortical index quantitatively.

    PubMed

    Yasar, Fusun; Akgunlu, Faruk

    2008-10-01

    The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape. Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718-0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology. It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758). FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs.

  19. Evaluating Mandibular Cortical Index Quantitatively

    PubMed Central

    Yasar, Fusun; Akgunlu, Faruk

    2008-01-01

    Objectives The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape. Methods Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718–0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology. Results It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758). Conclusions FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs. PMID:19212535

  20. Modeling cortical circuits.

    SciTech Connect

    Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

    2010-09-01

    The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.

  1. Bounds for Eigenvalues of ArrowheadMatrices and Their Applications to HubMatrices andWireless Communications

    DTIC Science & Technology

    2009-01-01

    recent work on the hub matrix theory [9] and its applications to multiple - input and multiple output ( MIMO ) wireless communication systems. A matrix, sayA...applications of these results to hub matrices and wireless communications are discussed. 15. SUBJECT TERMS Matrix Calculus, Signal Processing, MIMO ...makes them sharper. In [9], the hub matrix theory is also applied to the MIMO beamforming problem by comparing k of m transmitting antennas with the

  2. Mammalian Target of Rapamycin (mTOR) Activation In Focal Cortical Dysplasia and Related Focal Cortical Malformations

    PubMed Central

    Wong, Michael

    2011-01-01

    Focal cortical dysplasia (FCD) and other localized malformations of cortical development represent common causes of intractable pediatric epilepsy. Insights into the cellular and molecular pathogenesis of focal cortical malformations may reveal information about associated mechanisms of epileptogenesis and suggest new therapies for seizures caused by these developmental lesions. In animal models and human studies of FCD and the related disease of Tuberous Sclerosis Complex (TSC), the mammalian target of rapamycin (mTOR) pathway has been implicated in mediating cellular and molecular changes leading to the formation of the cortical malformations and the expression of epilepsy. The use of mTOR inhibitors may represent a rational therapeutic strategy for treating or even preventing epilepsy due to FCD and TSC. PMID:22015915

  3. Differentially expressed proteins underlying childhood cortical dysplasia with epilepsy identified by iTRAQ proteomic profiling

    PubMed Central

    Liu, Shiyong; Liu, Yi; Yang, Yixuan; Yang, Hui; Chen, Yangmei; Chen, Lifen

    2017-01-01

    Cortical dysplasia accounts for at least 14% of epilepsy cases, and is mostly seen in children. However, the understanding of molecular mechanisms and pathogenesis underlying cortical dysplasia is limited. The aim of this cross-sectional study is to identify potential key molecules in the mechanisms of cortical dysplasia by screening the proteins expressed in brain tissues of childhood cortical dysplasia patients with epilepsy using isobaric tags for relative and absolute quantitation-based tandem mass spectrometry compared to controls, and several differentially expressed proteins that are not reported to be associated with cortical dysplasia previously were selected for validation using real-time polymerase chain reaction, immunoblotting and immunohistochemistry. 153 out of 3340 proteins were identified differentially expressed between childhood cortical dysplasia patients and controls. And FSCN1, CRMP1, NDRG1, DPYSL5, MAP4, and FABP3 were selected for validation and identified to be increased in childhood cortical dysplasia patients, while PRDX6 and PSAP were identified decreased. This is the first report on differentially expressed proteins in childhood cortical dysplasia. We identified differential expression of FSCN1, CRMP1, NDRG1, DPYSL5, MAP4, FABP3, PRDX6 and PSAP in childhood cortical dysplasia patients, these proteins are involved in various processes and have various function. These results may provide new directions or targets for the research of childhood cortical dysplasia, and may be helpful in revealing molecular mechanisms and pathogenesis and/or pathophysiology of childhood cortical dysplasia if further investigated. PMID:28222113

  4. DataHub: Science data management in support of interactive exploratory analysis

    NASA Technical Reports Server (NTRS)

    Handley, Thomas H., Jr.; Rubin, Mark R.

    1993-01-01

    The DataHub addresses four areas of significant needs: scientific visualization and analysis; science data management; interactions in a distributed, heterogeneous environment; and knowledge-based assistance for these functions. The fundamental innovation embedded within the DataHub is the integration of three technologies, viz. knowledge-based expert systems, science visualization, and science data management. This integration is based on a concept called the DataHub. With the DataHub concept, science investigators are able to apply a more complete solution to all nodes of a distributed system. Both computational nodes and interactives nodes are able to effectively and efficiently use the data services (access, retrieval, update, etc), in a distributed, interdisciplinary information system in a uniform and standard way. This allows the science investigators to concentrate on their scientific endeavors, rather than to involve themselves in the intricate technical details of the systems and tools required to accomplish their work. Thus, science investigators need not be programmers. The emphasis on the definition and prototyping of system elements with sufficient detail to enable data analysis and interpretation leading to information. The DataHub includes all the required end-to-end components and interfaces to demonstrate the complete concept.

  5. DataHub - Science data management in support of interactive exploratory analysis

    NASA Technical Reports Server (NTRS)

    Handley, Thomas H., Jr.; Rubin, Mark R.

    1993-01-01

    DataHub addresses four areas of significant need: scientific visualization and analysis; science data management; interactions in a distributed, heterogeneous environment; and knowledge-based assistance for these functions. The fundamental innovation embedded within the DataHub is the integration of three technologies, viz. knowledge-based expert systems, science visualization, and science data management. This integration is based on a concept called the DataHub. With the DataHub concept, science investigators are able to apply a more complete solution to all nodes of a distributed system. Both computational nodes and interactive nodes are able to effectively and efficiently use the data services (access, retrieval, update, etc.) in a distributed, interdisciplinary information system in a uniform and standard way. This allows the science investigators to concentrate on their scientific endeavors, rather than to involve themselves in the intricate technical details of the systems and tools required to accomplish their work. Thus, science investigators need not be programmers. The emphasis is on the definition and prototyping of system elements with sufficient detail to enable data analysis and interpretation leading to information. The DataHub includes all the required end-to-end components and interfaces to demonstrate the complete concept.

  6. The Resource Hub: an innovative e-information service delivery model addressing mental health knowledge management.

    PubMed

    O'Sullivan, Julie; Powell, Jacinta; Gibbon, Peter; Emmerson, Brett

    2009-01-01

    This paper outlines the development of the Resource Hub, an intranet-based electronic information service designed to improve knowledge management and staff satisfaction in the Inner North Brisbane Mental Health Service, Royal Brisbane and Women's Hospital, Metro North Health Service District. The Resource Hub was launched in April 2007. It encompasses a large range of electronically stored resources and clinically relevant information, including direct links to approved internet sites, psychoeducation resources, fact sheets, resource lists and details of current service research projects. The Hub will continue to expand over time, improving access to clinical service delivery resources. A significant review conducted in April 2008 resulted in modifications to further improve the content and design of the Hub. Ongoing evaluation incorporates regular usage monitoring and stakeholder satisfaction surveys. The Resource Hub is a service delivery innovation that effectively addresses mental health service knowledge management issues. It is a strategy that could readily be transferred to other district mental health services and to health services in general.

  7. Vermont Hub-and-Spoke Model of Care for Opioid Use Disorder: Development, Implementation, and Impact.

    PubMed

    Brooklyn, John R; Sigmon, Stacey C

    Opioid use disorders (OUDs) are reaching epidemic proportions in the United States, and many geographic areas struggle with a persistent shortage in availability of opioid agonist treatment. Over the past 5 years, Vermont addiction medicine physicians and public health leaders have responded to these challenges by developing an integrated hub-and-spoke opioid treatment network. In the present report, we review the development, implementation, and impact of this novel hub-and-spoke model for expanding OUD treatment in Vermont. Vermont's hub-and-spoke system has been implemented state-wide and well-received by providers and patients alike. Adoption of this model has been associated with substantial increases in the state's OUD treatment capacity, with Vermont now having the highest capacity for treating OUD in the United States with 10.56 people in treatment per 1000. There has been a 64% increase in physicians waivered to prescribe buprenorphine, a 50% increase in patients served per waivered physician, and a robust bidirectional transfer of patients between hubs and spokes based upon clinical need. Challenges to system implementation and important future directions are discussed. Development and implementation of a hub-and-spoke system of care has contributed substantially to improvements in opioid agonist treatment capacity in Vermont. This system may serve as a model for other states grappling with the current opioid use epidemic.

  8. DataHub - Science data management in support of interactive exploratory analysis

    NASA Technical Reports Server (NTRS)

    Handley, Thomas H., Jr.; Rubin, Mark R.

    1993-01-01

    DataHub addresses four areas of significant need: scientific visualization and analysis; science data management; interactions in a distributed, heterogeneous environment; and knowledge-based assistance for these functions. The fundamental innovation embedded within the DataHub is the integration of three technologies, viz. knowledge-based expert systems, science visualization, and science data management. This integration is based on a concept called the DataHub. With the DataHub concept, science investigators are able to apply a more complete solution to all nodes of a distributed system. Both computational nodes and interactive nodes are able to effectively and efficiently use the data services (access, retrieval, update, etc.) in a distributed, interdisciplinary information system in a uniform and standard way. This allows the science investigators to concentrate on their scientific endeavors, rather than to involve themselves in the intricate technical details of the systems and tools required to accomplish their work. Thus, science investigators need not be programmers. The emphasis is on the definition and prototyping of system elements with sufficient detail to enable data analysis and interpretation leading to information. The DataHub includes all the required end-to-end components and interfaces to demonstrate the complete concept.

  9. USDA Regional Climate Hubs - Partnering to bring information and tools to managers of working lands

    NASA Astrophysics Data System (ADS)

    Johnson, R.

    2014-12-01

    In February 2014, USDA announced the location of seven Regional Hubs for Risk Adaptation and Mitigation to Climate Change (Climate Hubs) and three "Sub Hubs". The mission of these Climate Hubs is to develop and deliver science-based region-specific information and technologies to agricultural and natural resource managers that enable climate-smart decision-making and to direct land managers to USDA programs that can assist them in implementing those decisions. This mission is similar to that of Cooperative Extension and the Agricultural Experiment Stations (both of which benefit from USDA funding); therefore it is crucial that we partner with Land Grant Universities in order to achieve this mission. As USDA stands up these Climate Hubs we are working closely with USDA agencies, Land Grant Universities, other federal climate science programs, and other partners to determine how best to provide usable information and tools to farmers, ranchers and forest land managers to enable them to make climate-smart decisions.

  10. Paroxysmal kinesigenic dyskinesia: cortical or non-cortical origin.

    PubMed

    van Strien, Teun W; van Rootselaar, Anne-Fleur; Hilgevoord, Anthony A J; Linssen, Wim H J P; Groffen, Alexander J A; Tijssen, Marina A J

    2012-06-01

    Paroxysmal kinesigenic dyskinesia (PKD) is characterized by involuntary dystonia and/or chorea triggered by a sudden movement. Cases are usually familial with an autosomal dominant inheritance. Hypotheses regarding the pathogenesis of PKD focus on the controversy whether PKD has a cortical or non-cortical origin. A combined familial trait of PKD and benign familial infantile seizures has been reported as the infantile convulsions and paroxysmal choreoathetosis (ICCA) syndrome. Here, we report a family diagnosed with ICCA syndrome with an Arg217STOP mutation. The index patient showed interictal EEG focal changes compatible with paroxysmal dystonic movements of his contralateral leg. This might support cortical involvement in PKD.

  11. Cultured Human Renal Cortical Cells

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During the STS-90 shuttle flight in April 1998, cultured renal cortical cells revealed new information about genes. Timothy Hammond, an investigator in NASA's microgravity biotechnology program was interested in culturing kidney tissue to study the expression of proteins useful in the treatment of kidney diseases. Protein expression is linked to the level of differentiation of the kidney cells, and Hammond had difficulty maintaining differentiated cells in vitro. Intrigued by the improvement in cell differentiation that he observed in rat renal cells cultured in NASA's rotating wall vessel (a bioreactor that simulates some aspects of microgravity) and during an experiment performed on the Russian Space Station Mir, Hammond decided to sleuth out which genes were responsible for controlling differentiation of kidney cells. To do this, he compared the gene activity of human renal cells in a variety of gravitational environments, including the microgravity of the space shuttle and the high-gravity environment of a centrifuge. Hammond found that 1,632 genes out of 10,000 analyzed changed their activity level in microgravity, more than in any of the other environments. These results have important implications for kidney research as well as for understanding the basic mechanism for controlling cell differentiation.

  12. Cultured Human Renal Cortical Cells

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During the STS-90 shuttle flight in April 1998, cultured renal cortical cells revealed new information about genes. Timothy Hammond, an investigator in NASA's microgravity biotechnology program was interested in culturing kidney tissue to study the expression of proteins useful in the treatment of kidney diseases. Protein expression is linked to the level of differentiation of the kidney cells, and Hammond had difficulty maintaining differentiated cells in vitro. Intrigued by the improvement in cell differentiation that he observed in rat renal cells cultured in NASA's rotating wall vessel (a bioreactor that simulates some aspects of microgravity) and during an experiment performed on the Russian Space Station Mir, Hammond decided to sleuth out which genes were responsible for controlling differentiation of kidney cells. To do this, he compared the gene activity of human renal cells in a variety of gravitational environments, including the microgravity of the space shuttle and the high-gravity environment of a centrifuge. Hammond found that 1,632 genes out of 10,000 analyzed changed their activity level in microgravity, more than in any of the other environments. These results have important implications for kidney research as well as for understanding the basic mechanism for controlling cell differentiation.

  13. Viewing a forelimb induces widespread cortical activations.

    PubMed

    Raos, Vassilis; Kilintari, Marina; Savaki, Helen E

    2014-04-01

    cortical network is recruited even by mere observation of an arm executing goalless movements, which partially overlaps with the cortical network supporting the execution and observation of goal-directed forelimb actions. Interestingly, this overlap concerns mainly lower order sensory-motor rather than higher order association prefrontal and parietal cortices. Our results demonstrate that in order to reveal the net effects specifically induced by observation of a purposeful reaching-to-grasp action, the use of an appropriate control taking into account the effects of viewing the object to be grasped, the reaching arm and the static hand is crucial. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Basic visual function and cortical thickness patterns in posterior cortical atrophy.

    PubMed

    Lehmann, Manja; Barnes, Josephine; Ridgway, Gerard R; Wattam-Bell, John; Warrington, Elizabeth K; Fox, Nick C; Crutch, Sebastian J

    2011-09-01

    Posterior cortical atrophy (PCA) is characterized by a progressive decline in higher-visual object and space processing, but the extent to which these deficits are underpinned by basic visual impairments is unknown. This study aimed to assess basic and higher-order visual deficits in 21 PCA patients. Basic visual skills including form detection and discrimination, color discrimination, motion coherence, and point localization were measured, and associations and dissociations between specific basic visual functions and measures of higher-order object and space perception were identified. All participants showed impairment in at least one aspect of basic visual processing. However, a number of dissociations between basic visual skills indicated a heterogeneous pattern of visual impairment among the PCA patients. Furthermore, basic visual impairments were associated with particular higher-order object and space perception deficits, but not with nonvisual parietal tasks, suggesting the specific involvement of visual networks in PCA. Cortical thickness analysis revealed trends toward lower cortical thickness in occipitotemporal (ventral) and occipitoparietal (dorsal) regions in patients with visuoperceptual and visuospatial deficits, respectively. However, there was also a lot of overlap in their patterns of cortical thinning. These findings suggest that different presentations of PCA represent points in a continuum of phenotypical variation.

  15. Identifying overlapping communities as well as hubs and outliers via nonnegative matrix factorization.

    PubMed

    Cao, Xiaochun; Wang, Xiao; Jin, Di; Cao, Yixin; He, Dongxiao

    2013-10-21

    Community detection is important for understanding networks. Previous studies observed that communities are not necessarily disjoint and might overlap. It is also agreed that some outlier vertices participate in no community, and some hubs in a community might take more important roles than others. Each of these facts has been independently addressed in previous work. But there is no algorithm, to our knowledge, that can identify these three structures altogether. To overcome this limitation, we propose a novel model where vertices are measured by their centrality in communities, and define the identification of overlapping communities, hubs, and outliers as an optimization problem, calculated by nonnegative matrix factorization. We test this method on various real networks, and compare it with several competing algorithms. The experimental results not only demonstrate its ability of identifying overlapping communities, hubs, and outliers, but also validate its superior performance in terms of clustering quality.

  16. Identifying overlapping communities as well as hubs and outliers via nonnegative matrix factorization

    PubMed Central

    Cao, Xiaochun; Wang, Xiao; Jin, Di; Cao, Yixin; He, Dongxiao

    2013-01-01

    Community detection is important for understanding networks. Previous studies observed that communities are not necessarily disjoint and might overlap. It is also agreed that some outlier vertices participate in no community, and some hubs in a community might take more important roles than others. Each of these facts has been independently addressed in previous work. But there is no algorithm, to our knowledge, that can identify these three structures altogether. To overcome this limitation, we propose a novel model where vertices are measured by their centrality in communities, and define the identification of overlapping communities, hubs, and outliers as an optimization problem, calculated by nonnegative matrix factorization. We test this method on various real networks, and compare it with several competing algorithms. The experimental results not only demonstrate its ability of identifying overlapping communities, hubs, and outliers, but also validate its superior performance in terms of clustering quality. PMID:24129402

  17. Surface-micromachined rotatable member having a low-contact-area hub

    DOEpatents

    Rodgers, M. Steven; Sniegowski, Jeffry J.; Krygowski, Thomas W.

    2003-11-18

    A surface-micromachined rotatable member formed on a substrate and a method for manufacturing thereof are disclosed. The surface-micromachined rotatable member, which can be a gear or a rotary stage, has a central hub, and an annulus connected to the central hub by an overarching bridge. The hub includes a stationary axle support attached to the substrate and surrounding an axle. The axle is retained within the axle support with an air-gap spacing therebetween of generally 0.3 .mu.m or less. The rotatable member can be formed by alternately depositing and patterning layers of a semiconductor (e.g. polysilicon or a silicon-germanium alloy) and a sacrificial material and then removing the sacrificial material, at least in part. The present invention has applications for forming micromechanical or microelectromechanical devices requiring lower actuation forces, and providing improved reliability.

  18. Surface--micromachined rotatable member having a low-contact-area hub

    DOEpatents

    Rodgers, M. Steven; Sniegowski, Jeffry J.

    2002-01-01

    A surface-micromachined rotatable member formed on a substrate and a method for manufacturing thereof are disclosed. The surface-micromachined rotatable member, which can be a gear or a rotary stage, has a central hub, and an annulus connected to the central hub by an overarching bridge. The hub includes a stationary axle support attached to the substrate and surrounding an axle. The axle is retained within the axle support with an air-gap spacing therebetween of generally 0.3 .mu.m or less. The rotatable member can be formed by alternately depositing and patterning layers of a semiconductor (e.g. polysilicon or a silicon-germanium alloy) and a sacrificial material and then removing the sacrificial material, at least in part. The present invention has applications for forming micromechanical or microelectromechanical devices requiring lower actuation forces, and providing improved reliability.

  19. Synchronization and long-time memory in neural networks with inhibitory hubs and synaptic plasticity