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Sample records for activity level-dependent synapse-specific

  1. Activity Level-Dependent Synapse-Specific AMPA Receptor Trafficking Regulates Transmission Kinetics

    PubMed Central

    Zhu, J. Julius

    2009-01-01

    Central glutamatergic synapses may express AMPA-sensitive glutamate receptors (AMPA-Rs) with distinct gating properties and exhibit different transmission dynamics, which are important for computing various synaptic inputs received at different populations of synapses. However, how glutamatergic synapses acquire AMPA-Rs with distinct kinetics to influence synaptic integration remains poorly understood. Here I report synapse-specific trafficking of distinct AMPA-Rs in rat cortical layer 4 stellate and layer 5 pyramidal neurons. The analysis indicates that in single layer 4 stellate neurons thalamocortical synapses generate faster synaptic responses than intracortical synapses. Moreover, GluR1-containing AMPA-Rs traffic selectively into intracortical synapses, and this process requires sensory experience-dependent activity and slows down transmission kinetics. GluR4-containing AMPA-Rs traffic more heavily into thalamocortical synapses than intracortical synapses, and this process requires spontaneous synaptic activity and speeds up transmission kinetics. GluR2-containing AMPA-Rs traffic equally into both thalamocortical and intracortical synapses, and this process requires no synaptic activity and resets transmission kinetics. Notably, synaptic trafficking of distinct AMPA-Rs differentially regulates synaptic integration. Thus, synapse-specific AMPA-R trafficking coarsely sets and synaptic activity finely tunes transmission kinetics and integration properties at different synapses in central neurons. PMID:19439609

  2. NO signalling decodes frequency of neuronal activity and generates synapse-specific plasticity in mouse cerebellum

    PubMed Central

    Namiki, Shigeyuki; Kakizawa, Sho; Hirose, Kenzo; Iino, Masamitsu

    2005-01-01

    Nitric oxide (NO) is an intercellular messenger regulating neuronal functions. To visualize NO signalling in the brain, we generated a novel fluorescent NO indicator, which consists of the heme-binding region (HBR) of soluble guanylyl cyclase and the green fluorescent protein. The indicator (HBR–GFP) was expressed in the Purkinje cells of the mouse cerebellum and we imaged NO signals in acute cerebellar slices upon parallel fibre (PF) activation with a train of burst stimulations (BS, each BS consisting of five pulses at 50 Hz). Our results showed that the intensity of synaptic NO signal decays steeply with the distance from the synaptic input near PF–Purkinje cell synapses and generates synapse-specific long-term potentiation (LTP). Furthermore, the NO release level has a bell-shaped dependence on the frequency of PF activity. At an optimal frequency (1 Hz), but not at a low frequency (0.25 Hz) of a train of 60 BS, NO release as well as LTP was induced. However, both NO release and LTP were significantly reduced at higher frequencies (2–4 Hz) of BS train due to cannabinoid receptor-mediated retrograde inhibition of NO generation at the PF terminals. These results suggest that synaptic NO signalling decodes the frequency of neuronal activity to mediate synaptic plasticity at the PF–Purkinje cell synapse. PMID:15919714

  3. Synapse-specific homeostatic mechanisms in the hippocampus.

    PubMed

    Deeg, Katherine E

    2009-02-01

    Homeostatic synaptic plasticity allows neural circuits to function stably despite fluctuations to their inputs. Previous work has shown that excitatory synaptic strength increases globally when neuronal inputs are chronically silenced. A recent paper by Kim and Tsien describes a new type of synapse-specific homeostatic plasticity in which input silencing causes simultaneous strengthening and weakening of different populations of excitatory synapses within a hippocampal network. These seemingly antagonistic homeostatic adaptations maintain synaptic gain and preserve overall network stability by limiting harmful reverberatory bursting, which may underlie epileptic seizures.

  4. Blood Oxygen Level-Dependent Activation of the Primary Visual Cortex Predicts Size Adaptation Illusion

    PubMed Central

    Pooresmaeili, Arezoo; Arrighi, Roberto; Biagi, Laura; Morrone, Maria Concetta

    2016-01-01

    In natural scenes, objects rarely occur in isolation but appear within a spatiotemporal context. Here, we show that the perceived size of a stimulus is significantly affected by the context of the scene: brief previous presentation of larger or smaller adapting stimuli at the same region of space changes the perceived size of a test stimulus, with larger adapting stimuli causing the test to appear smaller than veridical and vice versa. In a human fMRI study, we measured the blood oxygen level-dependent activation (BOLD) responses of the primary visual cortex (V1) to the contours of large-diameter stimuli and found that activation closely matched the perceptual rather than the retinal stimulus size: the activated area of V1 increased or decreased, depending on the size of the preceding stimulus. A model based on local inhibitory V1 mechanisms simulated the inward or outward shifts of the stimulus contours and hence the perceptual effects. Our findings suggest that area V1 is actively involved in reshaping our perception to match the short-term statistics of the visual scene. PMID:24089504

  5. Application of mean-shift clustering to Blood oxygen level dependent functional MRI activation detection

    PubMed Central

    2014-01-01

    Background Functional magnetic resonance imaging (fMRI) analysis is commonly done with cross-correlation analysis (CCA) and the General Linear Model (GLM). Both CCA and GLM techniques, however, typically perform calculations on a per-voxel basis and do not consider relationships neighboring voxels may have. Clustered voxel analyses have then been developed to improve fMRI signal detections by taking advantages of relationships of neighboring voxels. Mean-shift clustering (MSC) is another technique which takes into account properties of neighboring voxels and can be considered for enhancing fMRI activation detection. Methods This study examines the adoption of MSC to fMRI analysis. MSC was applied to a Statistical Parameter Image generated with the CCA technique on both simulated and real fMRI data. The MSC technique was then compared with CCA and CCA plus cluster analysis. A range of kernel sizes were used to examine how the technique behaves. Results Receiver Operating Characteristic curves shows an improvement over CCA and Cluster analysis. False positive rates are lower with the proposed technique. MSC allows the use of a low intensity threshold and also does not require the use of a cluster size threshold, which improves detection of weak activations and highly focused activations. Conclusion The proposed technique shows improved activation detection for both simulated and real Blood Oxygen Level Dependent fMRI data. More detailed studies are required to further develop the proposed technique. PMID:24495795

  6. Suppressed Neuronal Activity and Concurrent Arteriolar Vasoconstriction May Explain Negative Blood Oxygenation Level-Dependent Signal

    PubMed Central

    Devor, Anna; Tian, Peifang; Nishimura, Nozomi; Teng, Ivan C.; Hillman, Elizabeth M. C.; Narayanan, S. N.; Ulbert, Istvan; Boas, David A.; Kleinfeld, David; Dale, Anders M.

    2009-01-01

    Synaptic transmission initiates a cascade of signal transduction events that couple neuronal activity to local changes in blood flow and oxygenation. Although a number of vasoactive molecules and specific cell types have been implicated, the transformation of stimulus-induced activation of neuronal circuits to hemodynamic changes is still unclear. We use somatosensory stimulation and a suite of in vivo imaging tools to study neurovascular coupling in rat primary somatosensory cortex. Our stimulus evoked a central region of net neuronal depolarization surrounded by net hyperpolarization. Hemodynamic measurements revealed that predominant depolarization corresponded to an increase in oxygenation, whereas predominant hyperpolarization corresponded to a decrease in oxygenation. On the microscopic level of single surface arterioles, the response was composed of a combination of dilatory and constrictive phases. Critically, the relative strength of vasoconstriction covaried with the relative strength of oxygenation decrease and neuronal hyperpolarization. These results suggest that a neuronal inhibition and concurrent arteriolar vasoconstriction correspond to a decrease in blood oxygenation, which would be consistent with a negative blood oxygenation level-dependent functional magnetic resonance imaging signal. PMID:17442830

  7. Bursty bulk flows at different magnetospheric activity levels: Dependence on IMF conditions

    NASA Astrophysics Data System (ADS)

    Zhang, L. Q.; Baumjohann, W.; Wang, C.; Dai, L.; Tang, B. B.

    2016-09-01

    Based on concurrent observations of the ACE and Geotail satellites from 1998 to 2005, we statistically analyzed and compared the earthward bursty bulk flows (BBFs) with local positive Bz under different interplanetary magnetic field (IMF) conditions. Four different magnetospheric activity levels (MALs), including quiet times and substorm growth/expansion/recovery phases, are considered. The properties of the BBFs, including their ion temperature (T), Vx component, x component of the energy flux density (Qx), and the solar wind dawn-dusk electric field Ey (observed at 1 AU), are analyzed. Main observations include the following: (1) BBF tends to have less penetration distance for northward IMF (NW-IMF) than for southward IMF (SW-IMF). Inward of 15 RE the BBFs for SW-IMF are dominant. Few BBFs for NW-IMF occur within 15 RE. (2) The occurrence probabilities of the BBFs at each MAL depend highly on the orientations of the IMF. During quiet times, the BBFs for NW-IMF are dominant. Reversely, during the growth and expansion phases of a substorm, the BBFs for SW-IMF are dominant. (3) The strengths of the BBF have significant evolution with substorm development. For SW-IMF condition, the strengths of the BBFs are the lowest for quiet times. The strength of the BBFs tends to increase during the growth phase and reaches to the strongest value during the expansion phase, then, decays during the recovery phase. For NW-IMF condition, the strengths of the BBFs evolve with the substorm development in a similar way as for SW-IMF condition. (4) For SW-IMF, the solar wind Ey evolves with the substorm development in a similar way to the strength of the BBFs. However, no clear evolution is found for NW-IMF. (5) The strengths of the BBF Qx and solar wind Ey are closely related. Both tend to be stronger for growth phase than for quite time, reach the strongest for expansion phase, then decay for recovery phase. It appears that to trigger a substorm, the strength of the BBFs should

  8. CaMKII phosphorylation of the GABAA receptor: receptor subtype- and synapse-specific modulation

    PubMed Central

    Houston, Catriona M; He, Qionger; Smart, Trevor G

    2009-01-01

    As a major inhibitory neurotransmitter, GABA plays a vital role in the brain by controlling the extent of neuronal excitation. This widespread role is reflected by the ubiquitous distribution of GABAA receptors throughout the central nervous system. To regulate the level of neuronal inhibition requires some endogenous control over the release of GABA and/or its postsynaptic response. In this context, Ca2+ ions are often used as primary or secondary messengers frequently resulting in the activation of protein kinases and phosphatases. One such kinase, Ca2+/calmodulin-dependent protein kinase II (CaMKII), can target the GABAA receptor to cause its phosphorylation. Evidence is now emerging, which is reviewed here, that GABAA receptors are indeed substrates for CaMKII and that this covalent modification alters the expression of cell surface receptors and their function. This type of regulation can also feature at inhibitory synapses leading to long-term inhibitory synaptic plasticity. Most recently, CaMKII has now been proposed to differentially phosphorylate particular isoforms of GABAA receptors in a synapse-specific context. PMID:19332484

  9. Diminished KCC2 confounds synapse-specificity of LTP during senescence

    PubMed Central

    Ferando, Isabella; Faas, Guido; Mody, Istvan

    2016-01-01

    Synapse-specificity of LTP ensures that no interference arises from inputs irrelevant to the memory to be encoded. In hippocampi of aged (21-28 months-old) mice LTP was relayed to unstimulated synapses blemishing its synapse-specificity. Diminished levels of the K+/Cl– cotransporter KCC2 and a depolarizing GABAA receptor-mediated synaptic component following LTP were the most likely causes for spreading the potentiation, unveiling novel mechanisms hindering information storage in the aged brain, and identifying KCC2 as a potential target for intervention. PMID:27500406

  10. Temporal Information Entropy of the Blood-Oxygenation Level-Dependent Signals Increases in the Activated Human Primary Visual Cortex.

    PubMed

    DiNuzzo, Mauro; Mascali, Daniele; Moraschi, Marta; Bussu, Giorgia; Maraviglia, Bruno; Mangia, Silvia; Giove, Federico

    2017-01-01

    Time-domain analysis of blood-oxygenation level-dependent (BOLD) signals allows the identification of clusters of voxels responding to photic stimulation in primary visual cortex (V1). However, the characterization of information encoding into temporal properties of the BOLD signals of an activated cluster is poorly investigated. Here, we used Shannon entropy to determine spatial and temporal information encoding in the BOLD signal within the most strongly activated area of the human visual cortex during a hemifield photic stimulation. We determined the distribution profile of BOLD signals during epochs at rest and under stimulation within small (19-121 voxels) clusters designed to include only voxels driven by the stimulus as highly and uniformly as possible. We found consistent and significant increases (2-4% on average) in temporal information entropy during activation in contralateral but not ipsilateral V1, which was mirrored by an expected loss of spatial information entropy. These opposite changes coexisted with increases in both spatial and temporal mutual information (i.e., dependence) in contralateral V1. Thus, we showed that the first cortical stage of visual processing is characterized by a specific spatiotemporal rearrangement of intracluster BOLD responses. Our results indicate that while in the space domain BOLD maps may be incapable of capturing the functional specialization of small neuronal populations due to relatively low spatial resolution, some information encoding may still be revealed in the temporal domain by an increase of temporal information entropy.

  11. Temporal information entropy of the Blood-Oxygenation Level-Dependent signals increases in the activated human primary visual cortex

    NASA Astrophysics Data System (ADS)

    DiNuzzo, Mauro; Mascali, Daniele; Moraschi, Marta; Bussu, Giorgia; Maraviglia, Bruno; Mangia, Silvia; Giove, Federico

    2017-02-01

    Time-domain analysis of blood-oxygenation level-dependent (BOLD) signals allows the identification of clusters of voxels responding to photic stimulation in primary visual cortex (V1). However, the characterization of information encoding into temporal properties of the BOLD signals of an activated cluster is poorly investigated. Here, we used Shannon entropy to determine spatial and temporal information encoding in the BOLD signal within the most strongly activated area of the human visual cortex during a hemifield photic stimulation. We determined the distribution profile of BOLD signals during epochs at rest and under stimulation within small (19-121 voxels) clusters designed to include only voxels driven by the stimulus as highly and uniformly as possible. We found consistent and significant increases (2-4% on average) in temporal information entropy during activation in contralateral but not ipsilateral V1, which was mirrored by an expected loss of spatial information entropy. These opposite changes coexisted with increases in both spatial and temporal mutual information (i.e. dependence) in contralateral V1. Thus, we showed that the first cortical stage of visual processing is characterized by a specific spatiotemporal rearrangement of intracluster BOLD responses. Our results indicate that while in the space domain BOLD maps may be incapable of capturing the functional specialization of small neuronal populations due to relatively low spatial resolution, some information encoding may still be revealed in the temporal domain by an increase of temporal information entropy.

  12. Synapse-specific stabilization of plasticity processes: the synaptic tagging and capture hypothesis revisited 10 years later.

    PubMed

    Barco, Angel; Lopez de Armentia, Mikel; Alarcon, Juan M

    2008-01-01

    A decade ago, the synaptic tagging hypothesis was proposed to explain how newly synthesized plasticity products can be specifically targeted to active synapses. A growing number of studies have validated the seminal findings that gave rise to this model, as well as contributed to unveil and expand the range of mechanisms underlying late-associativity and neuronal computation. Here, we will review what it was learnt during this past decade regarding the cellular and molecular mechanisms underlying synaptic tagging and synaptic capture. The accumulated experimental evidence has widened the theoretical framework set by the synaptic tagging and capture (STC) model and introduced concepts that were originally considered part of alternative models for explaining synapse-specific long-term potentiation (LTP). As a result, we believe that the STC model, now improved and expanded with these new ideas and concepts, still represents the most compelling hypothesis to explain late-associativity in synapse-specific plasticity processes. We will also discuss the impact of this model in our view of the integrative capability of neurons and associative learning.

  13. Identity of the NMDA receptor coagonist is synapse specific and developmentally regulated in the hippocampus.

    PubMed

    Le Bail, Matildé; Martineau, Magalie; Sacchi, Silvia; Yatsenko, Natalia; Radzishevsky, Inna; Conrod, Sandrine; Ait Ouares, Karima; Wolosker, Herman; Pollegioni, Loredano; Billard, Jean-Marie; Mothet, Jean-Pierre

    2015-01-13

    NMDA receptors (NMDARs) require the coagonists D-serine or glycine for their activation, but whether the identity of the coagonist could be synapse specific and developmentally regulated remains elusive. We therefore investigated the contribution of D-serine and glycine by recording NMDAR-mediated responses at hippocampal Schaffer collaterals (SC)-CA1 and medial perforant path-dentate gyrus (mPP-DG) synapses in juvenile and adult rats. Selective depletion of endogenous coagonists with enzymatic scavengers as well as pharmacological inhibition of endogenous D-amino acid oxidase activity revealed that D-serine is the preferred coagonist at SC-CA1 mature synapses, whereas, unexpectedly, glycine is mainly involved at mPP-DG synapses. Nevertheless, both coagonist functions are driven by the levels of synaptic activity as inferred by recording long-term potentiation generated at both connections. This regional compartmentalization in the coagonist identity is associated to different GluN1/GluN2A to GluN1/GluN2B subunit composition of synaptic NMDARs. During postnatal development, the replacement of GluN2B- by GluN2A-containing NMDARs at SC-CA1 synapses parallels a change in the identity of the coagonist from glycine to D-serine. In contrast, NMDARs subunit composition at mPP-DG synapses is not altered and glycine remains the main coagonist throughout postnatal development. Altogether, our observations disclose an unprecedented relationship in the identity of the coagonist not only with the GluN2 subunit composition at synaptic NMDARs but also with astrocyte activity in the developing and mature hippocampus that reconciles the complementary functions of D-serine And Glycine In Modulating Nmdars During The Maturation Of Tripartite Glutamatergic Synapses.

  14. Synapse-specific compartmentalization of signaling cascades for LTP induction in CA3 interneurons.

    PubMed

    Galván, E J; Pérez-Rosello, T; Gómez-Lira, G; Lara, E; Gutiérrez, R; Barrionuevo, G

    2015-04-02

    Inhibitory interneurons with somata in strata radiatum and lacunosum-molecular (SR/L-M) of hippocampal area CA3 receive excitatory input from pyramidal cells via the recurrent collaterals (RCs), and the dentate gyrus granule cells via the mossy fibers (MFs). Here we demonstrate that Hebbian long-term potentiation (LTP) at RC synapses on SR/L-M interneurons requires the concomitant activation of calcium-impermeable AMPARs (CI-AMPARs) and N-methyl-d-aspartate receptors (NMDARs). RC LTP was prevented by voltage clamping the postsynaptic cell during high-frequency stimulation (HFS; 3 trains of 100 pulses delivered at 100 Hz every 10s), with intracellular injections of the Ca(2+) chelator BAPTA (20mM), and with the NMDAR antagonist D-AP5. In separate experiments, RC and MF inputs converging onto the same interneuron were sequentially activated. We found that RC LTP induction was blocked by inhibitors of the calcium/calmodulin-dependent protein kinase II (CaMKII; KN-62, 10 μM or KN-93, 10 μM) but MF LTP was CaMKII independent. Conversely, the application of the protein kinase A (PKA) activators forskolin/IBMX (50 μM/25 μM) potentiated MF EPSPs but not RC EPSPs. Together these data indicate that the aspiny dendrites of SR/L-M interneurons compartmentalize synapse-specific Ca(2+) signaling required for LTP induction at RC and MF synapses. We also show that the two signal transduction cascades converge to activate a common effector, protein kinase C (PKC). Specifically, LTP at RC and MF synapses on the same SR/LM interneuron was blocked by postsynaptic injections of chelerythrine (10 μM). These data indicate that both forms of LTP share a common mechanism involving PKC-dependent signaling modulation.

  15. Glucocorticoids Regulate Glutamate and GABA Synapse-Specific Retrograde Transmission via Divergent Non-Genomic Signaling Pathways

    PubMed Central

    Di, Shi; Maxson, Marc M.; Franco, Alier; Tasker, Jeffrey G.

    2009-01-01

    Glucocorticoids exert an opposing rapid regulation of glutamate and GABA synaptic inputs to hypothalamic magnocellular neurons via the activation of postsynaptic membrane-associated receptors and the release of retrograde messengers. Glucocorticoids suppress synaptic glutamate release via the retrograde release of endocannabinoids and facilitate synaptic GABA release via an unknown retrograde messenger. Here, we show that the glucocorticoid facilitation of GABA inputs is due to the retrograde release of neuronal nitric oxide, and that glucocorticoid-induced endocannabinoid synthesis and nitric oxide synthesis are mediated by divergent G protein signaling mechanisms. While the glucocorticoid-induced, endocannabinoid-mediated suppression of glutamate release is dependent on activation of the Gαs G protein subunit and cAMP-PKA activation, the nitric oxide facilitation of GABA release is mediated by Gβγ signaling that leads to activation of neuronal nitric oxide synthase. Our findings indicate, therefore, that glucocorticoids exert opposing rapid actions on glutamate and GABA release by activating divergent G protein signaling pathways that trigger the synthesis of, and glutamate and GABA synapse-specific retrograde actions of, endocannabinoids and nitric oxide, respectively. The simultaneous rapid stimulation of nitric oxide and endocannabinoid synthesis by glucocorticoids has important implications for the impact of stress on the brain as well as on neural-immune interactions in the hypothalamus. PMID:19144839

  16. No increase of the blood oxygenation level-dependent functional magnetic resonance imaging signal with higher field strength: implications for brain activation studies.

    PubMed

    Seehafer, Jörg U; Kalthoff, Daniel; Farr, Tracy D; Wiedermann, Dirk; Hoehn, Mathias

    2010-04-14

    Experimental data up to 7.0 T show that the blood oxygenation level-dependent (BOLD) signal of functional magnetic resonance imaging (fMRI) increases with higher magnetic field strength. Although several studies at 11.7 T report higher BOLD signal compared with studies at 7.0 T, no direct comparison at these two field strengths has been performed under the exact same conditions. It therefore remains unclear whether the expected increase of BOLD effect with field strength will still continue to hold for fields >7.0 T. To examine this issue, we compared the BOLD activation signal at 7.0 and 11.7 T with the two common sequences, spin-echo (SE) and gradient-echo (GE) echo planar imaging (EPI). We chose the physiologically well controlled rat model of electrical forepaw stimulation under medetomidine sedation. While a linear to superlinear increase in activation with field strengths up to 7.0 T was reported in the literature, we observed no significant activation difference between 7.0 and 11.7 T with either SE or GE. Discussing the results in light of the four-component model of the BOLD signal, we showed that at high field only two extravascular contributions remain relevant, while both intravascular components vanish. Constancy of the BOLD effect is discussed due to motional narrowing, i.e., susceptibility gradients become so strong that phase variance of diffusing spins decreases and therefore the BOLD signal also decreases. This finding will be of high significance for the planning of future human and animal fMRI studies at high fields and their quantitative analysis.

  17. Comparison of blood-oxygen-level-dependent functional magnetic resonance imaging and near-infrared spectroscopy recording during functional brain activation in patients with stroke and brain tumors.

    PubMed

    Sakatani, Kaoru; Murata, Yoshihiro; Fujiwara, Norio; Hoshino, Tatsuya; Nakamura, Shin; Kano, Tsuneo; Katayama, Yoichi

    2007-01-01

    Blood-oxygen-level-dependent contrast functional magnetic resonance imaging (BOLD-fMRI) has been used to perform functional imaging in brain disorders such as stroke and brain tumors. However, recent studies have revealed that BOLD-fMRI does not image activation areas correctly in such patients. To clarify the characteristics of the evoked cerebral blood oxygenation (CBO) changes occurring in stroke and brain tumors, we have been comparing near-infrared spectroscopy (NIRS) and BOLD-fMRI recording during functional brain activation in these patients. We review our recent studies and related functional imaging studies on the brain disorders. In the primary sensorimotor cortex (PSMC) on the nonlesion side, the motor task consistently caused a decrease of deoxyhemoglobin (deoxy-Hb) with increases of oxyhemoglobin (oxy-Hb) and total hemoglobin (t-Hb), which is consistent with the evoked CBO response observed in normal adults. BOLD-fMRI demonstrated robust activation areas on the nonlesion side. In stroke patients, severe cerebral ischemia (i.e., misery perfusion) caused an increase of deoxy-Hb during the task, associated with increases of oxy-Hb and t-Hb, in the PSMC on the lesion side. In addition, the activation volume of BOLD-fMRI was significantly reduced on the lesion side. The BOLD signal did not change in some areas of the PSMC on the lesion side, but it tended to decrease in other areas during the tasks. In brain tumors, BOLD-fMRI clearly demonstrated activation areas in the PSMC on the lesion side in patients who displayed a normal evoked CBO response. However, the activation volume on the lesion side was significantly reduced in patients who exhibited an increase of deoxy-Hb during the task. In both stroke and brain tumors, false-negative activations (i.e., marked reductions of activation volumes) in BOLD imaging were associated with increases of deoxy-Hb, which could cause a reduction in BOLD signal. BOLD-fMRI investigations of patients with brain disorders

  18. Neurogliaform cells dynamically regulate somatosensory integration via synapse-specific modulation

    PubMed Central

    Chittajallu, Ramesh; Pelkey, Kenneth A; McBain, Chris J

    2014-01-01

    Despite the prevailing idea that neurogliaform cells produce a spatially unrestricted widespread inhibition, we demonstrate here that their activity attenuates thalamic-evoked feed-forward inhibition in layer IV barrel cortex but has no effect on feed-forward excitation. The result of this circuit selectivity is a dynamic regulation in the temporal window for integration of excitatory thalamic input, thus revealing a new role for neurogliaform cells in shaping sensory processing. PMID:23222912

  19. Synapse-specific compartmentalization of signaling cascades for LTP induction in CA3 interneurons

    PubMed Central

    Galván, Emilio J; Pérez-Rosello, Tamara; Gómez-Lira, Gisela; Lara, Erika; Gutiérrez, Rafael; Barrionuevo, Germán

    2015-01-01

    Inhibitory interneurons with somata in strata radiatum and lacunosun-moleculare (SR/L-M) of hippocampal area CA3 receive excitatory input from pyramidal cells via the recurrent collaterals (RC), and the dentate gyrus granule cells via the mossy fibers (MFs). Here we demonstrate that Hebbian long-term potentiation (LTP) at RC synapses on SR/L-M interneurons requires the concomitant activation of calcium-impermeable AMPARs (CI- AMPARs) and NMDARs. RC LTP was prevented by voltage clamping the postsynaptic cell during high-frequency stimulation (HFS; 3 trains of 100 pulses delivered at 100 Hz every 10 s), with intracellular injections of the Ca2+ chelator BAPTA (20 mM), and with the N-methyl-D-aspartate receptor (NMDAR) antagonist D-AP5. In separate experiments, RC and MF inputs converging onto the same interneuron were sequentially activated. We found that RC LTP induction was blocked by inhibitors of the calcium/calmodulin-dependent protein kinase II (CaMKII; KN-62, 10 μM or KN-93, 10 μM) but MF LTP was CaMKII independent. Conversely, the application of the protein kinase A (PKA) activators forskolin/IBMX(50 μM/25 μM) potentiated MF EPSPs but not RC EPSPs. Together these data indicate that the aspiny dendrites of SR/L-M interneurons compartmentalize synaptic-specific Ca2+ signaling required for LTP induction at RC and MF synapses. We also show that the two signal transduction cascades converge to activate a common effector, protein kinase C (PKC). Specifically, LTP at RC and MF synapses on the same SR/LM interneuron was blocked by postsynaptic injections of chelerythrine (10 μM). These data indicate that both forms of LTP share a common mechanism involving PKC-dependent signaling modulation. PMID:25637803

  20. Synapse-specific mGluR1-dependent long-term potentiation in interneurones regulates mouse hippocampal inhibition

    PubMed Central

    Lapointe, Valérie; Morin, France; Ratté, Stéphanie; Croce, Ariane; Conquet, François; Lacaille, Jean-Claude

    2004-01-01

    Hippocampal CA1 inhibitory interneurones control the excitability and synchronization of pyramidal cells, and participate in hippocampal synaptic plasticity. Pairing theta-burst stimulation (TBS) with postsynaptic depolarization, we induced long-term potentiation (LTP) of putative single-fibre excitatory postsynaptic currents (EPSCs) in stratum oriens/alveus (O/A) interneurones of mouse hippocampal slices. LTP induction was absent in metabotropic glutamate receptor 1 (mGluR1) knockout mice, was correlated with the postsynaptic presence of mGluR1a, and required a postsynaptic Ca2+ rise. Changes in paired-pulse facilitation and coefficient of variation indicated that LTP expression involved presynaptic mechanisms. LTP was synapse specific, occurring selectively at synapses modulated by presynaptic group II, but not group III, mGluRs. Furthermore, the TBS protocol applied in O/A induced a long-term increase of polysynaptic inhibitory responses in CA1 pyramidal cells, that was absent in mGluR1 knockout mice. These results uncover the mechanisms of a novel form of interneurone synaptic plasticity that can adaptively regulate inhibition of hippocampal pyramidal cells. PMID:14673190

  1. Diurnal Variations in Neural Activity of Healthy Human Brain Decoded with Resting-State Blood Oxygen Level Dependent fMRI.

    PubMed

    Jiang, Chunxiang; Yi, Li; Su, Shi; Shi, Caiyun; Long, Xiaojing; Xie, Guoxi; Zhang, Lijuan

    2016-01-01

    It remains an ongoing investigation about how the neural activity alters with the diurnal rhythms in human brain. Resting-state functional magnetic resonance imaging (RS-fMRI) reflects spontaneous activities and/or the endogenous neurophysiological process of the human brain. In the present study, we applied the ReHo (regional homogeneity) and ALFF (amplitude of low frequency fluctuation) based on RS-fMRI to explore the regional differences in the spontaneous cerebral activities throughout the entire brain between the morning and evening sessions within a 24-h time cycle. Wide spread brain areas were found to exhibit diurnal variations, which may be attributed to the internal molecular systems regulated by clock genes, and the environmental factors including light-dark cycle, daily activities and homeostatic sleep drive. Notably, the diurnal variation of default mode network (DMN) suggests that there is an adaptation or compensation response within the subregions of DMN, implying a balance or a decoupling of regulation between these regions.

  2. Diurnal Variations in Neural Activity of Healthy Human Brain Decoded with Resting-State Blood Oxygen Level Dependent fMRI

    PubMed Central

    Jiang, Chunxiang; Yi, Li; Su, Shi; Shi, Caiyun; Long, Xiaojing; Xie, Guoxi; Zhang, Lijuan

    2016-01-01

    It remains an ongoing investigation about how the neural activity alters with the diurnal rhythms in human brain. Resting-state functional magnetic resonance imaging (RS-fMRI) reflects spontaneous activities and/or the endogenous neurophysiological process of the human brain. In the present study, we applied the ReHo (regional homogeneity) and ALFF (amplitude of low frequency fluctuation) based on RS-fMRI to explore the regional differences in the spontaneous cerebral activities throughout the entire brain between the morning and evening sessions within a 24-h time cycle. Wide spread brain areas were found to exhibit diurnal variations, which may be attributed to the internal molecular systems regulated by clock genes, and the environmental factors including light-dark cycle, daily activities and homeostatic sleep drive. Notably, the diurnal variation of default mode network (DMN) suggests that there is an adaptation or compensation response within the subregions of DMN, implying a balance or a decoupling of regulation between these regions. PMID:28066207

  3. Synapse-specific contribution of the variation of transmitter concentration to the decay of inhibitory postsynaptic currents.

    PubMed Central

    Nusser, Z; Naylor, D; Mody, I

    2001-01-01

    Synaptic transmission is characterized by a remarkable trial-to-trial variability in the postsynaptic response, influencing the way in which information is processed in neuronal networks. This variability may originate from the probabilistic nature of quantal transmitter release, from the stochastic behavior of the receptors, or from the fluctuation of the transmitter concentration in the cleft. We combined nonstationary noise analysis and modeling techniques to estimate the contribution of transmitter fluctuation to miniature inhibitory postsynaptic current (mIPSC) variability. A substantial variability (approximately 30%) in mIPSC decay was found in all cell types studied (neocortical layer2/3 pyramidal cells, granule cells of the olfactory bulb, and interneurons of the cerebellar molecular layer). This large variability was not solely the consequence of the expression of multiple types of GABA(A) receptors, as a similar mIPSC decay variability was observed in cerebellar interneurons that express only a single type (alpha(1)beta(2)gamma(2)) of GABA(A) receptor. At large synapses on these cells, all variance in mIPSC decay could be accounted for by the stochastic behavior of approximately 36 pS channels, consistent with the conductance of alpha(1)beta(2)gamma(2) GABA(A) receptors at physiological temperatures. In contrast, at small synapses, a significant amount of variability in the synaptic cleft GABA transient had to be present to account for the additional variance in IPSC decay over that produced by stochastic channel openings. Thus, our results suggest a synapse-specific contribution of the variation of the spatiotemporal profile of GABA to the decay of IPSCs. PMID:11222289

  4. Interactions between innexins UNC-7 and UNC-9 mediate electrical synapse specificity in the Caenorhabditis elegans locomotory nervous system

    PubMed Central

    Starich, Todd A; Xu, Ji; Skerrett, I Martha; Nicholson, Bruce J; Shaw, Jocelyn E

    2009-01-01

    Background Approximately 10% of Caenorhabditis elegans nervous system synapses are electrical, that is, gap junctions composed of innexins. The locomotory nervous system consists of several pairs of interneurons and three major classes of motor neurons, all with stereotypical patterns of connectivity that include gap junctions. Mutations in the two innexin genes unc-7 and unc-9 result in identical uncoordinated movement phenotypes, and their respective gene products were investigated for their contribution to electrical synapse connectivity. Results unc-7 encodes three innexin isoforms. Two of these, UNC-7S and UNC-7SR, are functionally equivalent and play an essential role in coordinated locomotion. UNC-7S and UNC-7SR are widely expressed and co-localize extensively with green fluorescent protein-tagged innexin UNC-9 in the ventral and dorsal nerve cords. A subset of UNC-7S/SR expression visualizes gap junctions formed between the AVB forward command interneurons and their B class motor neuron partners. Experiments indicate that expression of UNC-7S/SR in AVB and expression of UNC-9 in B motor neurons is necessary for these gap junctions to form. In Xenopus oocyte pairs, both UNC-7S and UNC-9 form homomeric gap junctions, and together they form heterotypic channels. Xenopus oocyte studies and co-localization studies in C. elegans suggest that UNC-7S and UNC-9 do not heteromerize in the same hemichannel, leading to the model that hemichannels in AVB:B motor neuron gap junctions are homomeric and heterotypic. Conclusion UNC-7S and UNC-9 are widely expressed and contribute to a large number of the gap junctions identified in the locomotory nervous system. Proper AVB:B gap junction formation requires UNC-7S expression in AVB interneurons and UNC-9 expression in B motor neurons. More broadly, this illustrates that innexin identity is critical for electrical synapse specificity, but differential (compartmentalized) innexin expression cannot account for all of the

  5. Environmental awareness and level-dependent hearing protection devices.

    PubMed

    Lindley, G A; Palmer, C V; Goldstein, H; Pratt, S

    1997-02-01

    The effect of level-dependent hearing protection devices (HPDs) on subjects' ability to identify real-life environmental sounds was investigated. Eighteen subjects with no hunting experience attempted to identify sounds (crow, duck, turkey, deer, owl, goose, and person) recorded at various distances in the presence of the SoundScope and Sonic II level-dependent HPDs as well as in an open ear condition. Knowles Electronic's Manikin for Auditory Research was employed in making the experimental recordings. The Sonic II accomplishes level-dependent attenuation via a passive mechanism, whereas the SoundScope employs active circuitry that attenuates loud sounds while providing a small amount of high frequency amplification for soft sounds. Both devices are commercially available and are advertised for hunters/shooters. Sound identification scores (SISs) were determined for each condition. Mean SISs differed significantly among the three earplug conditions, collapsed over type of sound and distance, with the best SIS obtained under the open ear condition (96.43%) and the worst under the Sonic II condition (84.13%). Further analysis revealed that the listening conditions differed significantly only at the 100 yard distance. Auditory awareness was not maintained by either device investigated during the 100 yard condition. However, auditory awareness was maintained by both devices at a distance of 75 yards or closer. These devices may be appropriate for use in certain hunting/shooting situations depending on several factors including type of game being hunted, environment, and shooting range of the weapon. Further support also is provided for the usage of level-dependent HPDs during recreational shooting activities (i.e., at a shooting range).

  6. Negative blood oxygen level dependent signals during speech comprehension.

    PubMed

    Rodriguez Moreno, Diana; Schiff, Nicholas D; Hirsch, Joy

    2015-05-01

    Speech comprehension studies have generally focused on the isolation and function of regions with positive blood oxygen level dependent (BOLD) signals with respect to a resting baseline. Although regions with negative BOLD signals in comparison to a resting baseline have been reported in language-related tasks, their relationship to regions of positive signals is not fully appreciated. Based on the emerging notion that the negative signals may represent an active function in language tasks, the authors test the hypothesis that negative BOLD signals during receptive language are more associated with comprehension than content-free versions of the same stimuli. Regions associated with comprehension of speech were isolated by comparing responses to passive listening to natural speech to two incomprehensible versions of the same speech: one that was digitally time reversed and one that was muffled by removal of high frequencies. The signal polarity was determined by comparing the BOLD signal during each speech condition to the BOLD signal during a resting baseline. As expected, stimulation-induced positive signals relative to resting baseline were observed in the canonical language areas with varying signal amplitudes for each condition. Negative BOLD responses relative to resting baseline were observed primarily in frontoparietal regions and were specific to the natural speech condition. However, the BOLD signal remained indistinguishable from baseline for the unintelligible speech conditions. Variations in connectivity between brain regions with positive and negative signals were also specifically related to the comprehension of natural speech. These observations of anticorrelated signals related to speech comprehension are consistent with emerging models of cooperative roles represented by BOLD signals of opposite polarity.

  7. Negative Blood Oxygen Level Dependent Signals During Speech Comprehension

    PubMed Central

    Rodriguez Moreno, Diana; Schiff, Nicholas D.

    2015-01-01

    Abstract Speech comprehension studies have generally focused on the isolation and function of regions with positive blood oxygen level dependent (BOLD) signals with respect to a resting baseline. Although regions with negative BOLD signals in comparison to a resting baseline have been reported in language-related tasks, their relationship to regions of positive signals is not fully appreciated. Based on the emerging notion that the negative signals may represent an active function in language tasks, the authors test the hypothesis that negative BOLD signals during receptive language are more associated with comprehension than content-free versions of the same stimuli. Regions associated with comprehension of speech were isolated by comparing responses to passive listening to natural speech to two incomprehensible versions of the same speech: one that was digitally time reversed and one that was muffled by removal of high frequencies. The signal polarity was determined by comparing the BOLD signal during each speech condition to the BOLD signal during a resting baseline. As expected, stimulation-induced positive signals relative to resting baseline were observed in the canonical language areas with varying signal amplitudes for each condition. Negative BOLD responses relative to resting baseline were observed primarily in frontoparietal regions and were specific to the natural speech condition. However, the BOLD signal remained indistinguishable from baseline for the unintelligible speech conditions. Variations in connectivity between brain regions with positive and negative signals were also specifically related to the comprehension of natural speech. These observations of anticorrelated signals related to speech comprehension are consistent with emerging models of cooperative roles represented by BOLD signals of opposite polarity. PMID:25412406

  8. On the level-dependent penalty for impulse sound.

    PubMed

    Vos, J

    1990-08-01

    At relatively low A-weighted equivalent levels (Leq), road-traffic sounds are rated to be less annoying than impulse sounds. The differences, however, decrease with increasing Leq of the sounds, which indicates that the penalty for impulse sound seems to be level dependent. It was questioned whether the decrease of the penalty with increasing Leq might, at least partly, have been a consequence of the use of the ten-point rating scale. In experiments 1 and 2, the relevance of the level-dependent correction was therefore studied further by using the method of adjustment. The mean results again showed that, at least for gunfire sounds (small arms), the penalty is level dependent. The drawing of firm conclusions, however, was hampered by a relatively large bias in the adjustments. In addition, the overall size of the penalty was lower than obtained in previous rating experiments. The question about the relevance of the level-dependent penalty was reopened in experiment 3 by applying the method of paired comparison. The results confirm the previous findings obtained with the rating experiments: For gunfire sounds at relatively low indoor Leq values, a penalty of about 10 dB is required, and a penalty lower than 5 dB can be applied only in conditions with rather high sound exposure. The results further showed that especially at indoor Leq values higher than about 45 to 50 dB(A), application of a negative penalty may become relevant for specific sounds such as those produced by the 0.50-in. machine gun. Consequently, acoustic measures from which to predict the value of the penalty are highly needed.

  9. On the level-dependent attenuation of a perforated device.

    PubMed

    Chen, Lan; Sang, Jinqiu; Li, Xiaodong

    2009-05-01

    To investigate the physical principle governing the level-dependent attenuation of a perforated earplug, a mathematical model is first established with the transfer-matrix method to calculate the noise reduction through a simplified device, one perforated panel with back cavity, mounted in an impedance tube. The model prediction is compared with the measured noise reduction through two series of large-scale devices and one device with the dimensions of the ear canal under continuous noise and sinusoidal excitations. The model helps to improve significantly the level-dependent attenuation of the large-scale device. It also illustrates that the attenuation is not solely determined by the resistance of the orifice, which has been a well accepted design concept, but resulted from an incorporated effect of the acoustic filter comprised of the acoustic impedance of the orifice and other elements in the earplug-ear-canal system. This mechanism can interpret a resonance at low incident levels on improper design and reveal approaches to eliminate it. Finally, the model's potential contributions to the design of a perforated earplug are discussed, along with the threshold of level-dependent attenuation supported with experimental evidence.

  10. Level dependence of spatial processing in the primate auditory cortex

    PubMed Central

    Wang, Xiaoqin

    2012-01-01

    Sound localization in both humans and monkeys is tolerant to changes in sound levels. The underlying neural mechanism, however, is not well understood. This study reports the level dependence of individual neurons' spatial receptive fields (SRFs) in the primary auditory cortex (A1) and the adjacent caudal field in awake marmoset monkeys. We found that most neurons' excitatory SRF components were spatially confined in response to broadband noise stimuli delivered from the upper frontal sound field. Approximately half the recorded neurons exhibited little change in spatial tuning width over a ∼20-dB change in sound level, whereas the remaining neurons showed either expansion or contraction in their tuning widths. Increased sound levels did not alter the percent distribution of tuning width for neurons collected in either cortical field. The population-averaged responses remained tuned between 30- and 80-dB sound pressure levels for neuronal groups preferring contralateral, midline, and ipsilateral locations. We further investigated the spatial extent and level dependence of the suppressive component of SRFs using a pair of sequentially presented stimuli. Forward suppression was observed when the stimuli were delivered from “far” locations, distant to the excitatory center of an SRF. In contrast to spatially confined excitation, the strength of suppression typically increased with stimulus level at both the excitatory center and far regions of an SRF. These findings indicate that although the spatial tuning of individual neurons varied with stimulus levels, their ensemble responses were level tolerant. Widespread spatial suppression may play an important role in limiting the sizes of SRFs at high sound levels in the auditory cortex. PMID:22592309

  11. Pricing of options on assets with level dependent stochastic volatility

    NASA Astrophysics Data System (ADS)

    Skabelin, Alexander

    2005-05-01

    Many asset classes, such as interest rates, exchange rates, commodities, and equities, often exhibit a strong relationship between asset prices and asset volatilities. This paper examines an analytical model that takes into account this level dependence of volatility. We demonstrate how prices of European options under stochastic volatility can be calculated analytically via inverse Laplace transformations. We also examine a Hull-White stochastic volatility expansion. While a success of this expansion in approximate computation of option prices has already been established empirically, the question of convergence has been left unanswered. We demonstrate, in this paper, that this expansion diverges essentially for all possible stochastic volatility processes. In contrast to a majority of volatility expansion models reported in the literature, we construct expansions that explicitly show the contribution of all of the variance moments. Such complete expansions are very useful in analyzing properties of option prices, as we demonstrate by examining why empirical volatility surfaces plotted as a function of the rescaled strike can sometimes exhibit striking time invariance.

  12. From blood oxygenation level dependent (BOLD) signals to brain temperature maps.

    PubMed

    Sotero, Roberto C; Iturria-Medina, Yasser

    2011-11-01

    A theoretical framework is presented for converting Blood Oxygenation Level Dependent (BOLD) images to brain temperature maps, based on the idea that disproportional local changes in cerebral blood flow (CBF) as compared with cerebral metabolic rate of oxygen consumption (CMRO₂) during functional brain activity, lead to both brain temperature changes and the BOLD effect. Using an oxygen limitation model and a BOLD signal model, we obtain a transcendental equation relating CBF and CMRO₂ changes with the corresponding BOLD signal, which is solved in terms of the Lambert W function. Inserting this result in the dynamic bioheat equation describing the rate of temperature changes in the brain, we obtain a nonautonomous ordinary differential equation that depends on the BOLD response, which is solved numerically for each brain voxel. Temperature maps obtained from a real BOLD dataset registered in an attention to visual motion experiment were calculated, obtaining temperature variations in the range: (-0.15, 0.1) which is consistent with experimental results. The statistical analysis revealed that significant temperature activations have a similar distribution pattern than BOLD activations. An interesting difference was the activation of the precuneus in temperature maps, a region involved in visuospatial processing, an effect that was not observed on BOLD maps. Furthermore, temperature maps were more localized to gray matter regions than the original BOLD maps, showing less activated voxels in white matter and cerebrospinal fluid.

  13. Missing Data Imputation versus Full Information Maximum Likelihood with Second-Level Dependencies

    ERIC Educational Resources Information Center

    Larsen, Ross

    2011-01-01

    Missing data in the presence of upper level dependencies in multilevel models have never been thoroughly examined. Whereas first-level subjects are independent over time, the second-level subjects might exhibit nonzero covariances over time. This study compares 2 missing data techniques in the presence of a second-level dependency: multiple…

  14. Missing Data Imputation versus Full Information Maximum Likelihood with Second-Level Dependencies

    ERIC Educational Resources Information Center

    Larsen, Ross

    2011-01-01

    Missing data in the presence of upper level dependencies in multilevel models have never been thoroughly examined. Whereas first-level subjects are independent over time, the second-level subjects might exhibit nonzero covariances over time. This study compares 2 missing data techniques in the presence of a second-level dependency: multiple…

  15. Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation

    PubMed Central

    Licata, Stephanie C.; Lowen, Steven B.; Trksak, George H.; MacLean, Robert R.; Lukas, Scott E.

    2011-01-01

    Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABAA receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess the effects of zolpidem within the brain. Healthy participants (n=12) were scanned 60 minutes after acute oral administration of zolpidem (0, 5, 10, or 20 mg), and changes in BOLD signal were measured in the visual cortex during presentation of a flashing checkerboard. Heart rate and oxygen saturation were monitored continuously throughout the session. Zolpidem (10 and 20 mg) reduced the robust visual system activation produced by presentation of this stimulus, but had no effects on physiological activity during the fMRI scan. Zolpidem’s modulation of the BOLD signal within the visual cortex is consistent with the abundant distribution of GABAA receptors localized in this region, as well as previous studies showing a relationship between increased GABA-mediated neuronal inhibition and a reduction in BOLD activation. PMID:21640782

  16. Impact of physiological noise correction on detecting blood oxygenation level-dependent contrast in the breast

    NASA Astrophysics Data System (ADS)

    Wallace, Tess E.; Manavaki, Roido; Graves, Martin J.; Patterson, Andrew J.; Gilbert, Fiona J.

    2017-01-01

    Physiological fluctuations are expected to be a dominant source of noise in blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) experiments to assess tumour oxygenation and angiogenesis. This work investigates the impact of various physiological noise regressors: retrospective image correction (RETROICOR), heart rate (HR) and respiratory volume per unit time (RVT), on signal variance and the detection of BOLD contrast in the breast in response to a modulated respiratory stimulus. BOLD MRI was performed at 3 T in ten volunteers at rest and during cycles of oxygen and carbogen gas breathing. RETROICOR was optimized using F-tests to determine which cardiac and respiratory phase terms accounted for a significant amount of signal variance. A nested regression analysis was performed to assess the effect of RETROICOR, HR and RVT on the model fit residuals, temporal signal-to-noise ratio, and BOLD activation parameters. The optimized RETROICOR model accounted for the largest amount of signal variance ( Δ R\\text{adj}2   =  3.3  ±  2.1%) and improved the detection of BOLD activation (P  =  0.002). Inclusion of HR and RVT regressors explained additional signal variance, but had a negative impact on activation parameter estimation (P  <  0.001). Fluctuations in HR and RVT appeared to be correlated with the stimulus and may contribute to apparent BOLD signal reactivity.

  17. The neural basis of the blood-oxygen-level-dependent functional magnetic resonance imaging signal.

    PubMed Central

    Logothetis, Nikos K

    2002-01-01

    Magnetic resonance imaging (MRI) has rapidly become an important tool in clinical medicine and biological research. Its functional variant (functional magnetic resonance imaging; fMRI) is currently the most widely used method for brain mapping and studying the neural basis of human cognition. While the method is widespread, there is insufficient knowledge of the physiological basis of the fMRI signal to interpret the data confidently with respect to neural activity. This paper reviews the basic principles of MRI and fMRI, and subsequently discusses in some detail the relationship between the blood-oxygen-level-dependent (BOLD) fMRI signal and the neural activity elicited during sensory stimulation. To examine this relationship, we conducted the first simultaneous intracortical recordings of neural signals and BOLD responses. Depending on the temporal characteristics of the stimulus, a moderate to strong correlation was found between the neural activity measured with microelectrodes and the BOLD signal averaged over a small area around the microelectrode tips. However, the BOLD signal had significantly higher variability than the neural activity, indicating that human fMRI combined with traditional statistical methods underestimates the reliability of the neuronal activity. To understand the relative contribution of several types of neuronal signals to the haemodynamic response, we compared local field potentials (LFPs), single- and multi-unit activity (MUA) with high spatio-temporal fMRI responses recorded simultaneously in monkey visual cortex. At recording sites characterized by transient responses, only the LFP signal was significantly correlated with the haemodynamic response. Furthermore, the LFPs had the largest magnitude signal and linear systems analysis showed that the LFPs were better than the MUAs at predicting the fMRI responses. These findings, together with an analysis of the neural signals, indicate that the BOLD signal primarily measures the input

  18. Biophysical and physiological origins of blood oxygenation level-dependent fMRI signals

    PubMed Central

    Kim, Seong-Gi; Ogawa, Seiji

    2012-01-01

    After its discovery in 1990, blood oxygenation level-dependent (BOLD) contrast in functional magnetic resonance imaging (fMRI) has been widely used to map brain activation in humans and animals. Since fMRI relies on signal changes induced by neural activity, its signal source can be complex and is also dependent on imaging parameters and techniques. In this review, we identify and describe the origins of BOLD fMRI signals, including the topics of (1) effects of spin density, volume fraction, inflow, perfusion, and susceptibility as potential contributors to BOLD fMRI, (2) intravascular and extravascular contributions to conventional gradient-echo and spin-echo BOLD fMRI, (3) spatial specificity of hemodynamic-based fMRI related to vascular architecture and intrinsic hemodynamic responses, (4) BOLD signal contributions from functional changes in cerebral blood flow (CBF), cerebral blood volume (CBV), and cerebral metabolic rate of O2 utilization (CMRO2), (5) dynamic responses of BOLD, CBF, CMRO2, and arterial and venous CBV, (6) potential sources of initial BOLD dips, poststimulus BOLD undershoots, and prolonged negative BOLD fMRI signals, (7) dependence of stimulus-evoked BOLD signals on baseline physiology, and (8) basis of resting-state BOLD fluctuations. These discussions are highly relevant to interpreting BOLD fMRI signals as physiological means. PMID:22395207

  19. Sound level dependence of auditory evoked potentials: simultaneous EEG recording and low-noise fMRI.

    PubMed

    Thaerig, Stefanie; Behne, Nicole; Schadow, Jeanette; Lenz, Daniel; Scheich, Henning; Brechmann, André; Herrmann, Christoph S

    2008-03-01

    The simultaneous recording of EEG and fMRI offers the advantage of combining precise spatial information about neuronal processing obtained by fMRI data with the high temporal resolution of EEG data. One problem for the analysis of auditory processing, however, is the noisy environment during fMRI measurements, especially when EPI sequences are employed. While EEG studies outside an MRI scanner repeatedly demonstrated a clear sound level-dependent increase of N1 amplitude, this finding was less obvious in simultaneous recordings inside a scanner. Based on the assumption that this inconsistency might be due to the confounding effect of the rather loud EPI noise, we employed a low-noise fMRI protocol. This method was previously used to reveal level-dependent fMRI activation in auditory cortex areas. We combined this method with simultaneous EEG recordings to investigate the effect of different sound intensities on the auditory evoked potentials. Eight participants without hearing deficits took part in our experiment. Frequency modulated tones (FM) were presented monaurally with two sound intensities (60 and 80 dB HL). The task of the participants was to categorize the FM-direction (rising vs. falling). Our results inside the scanner replicate the sound level dependence of AEPs from previous EEG studies outside the scanner. The data analysis revealed a significant shortening of N1 latency and an increase in the N1-P2 peak-to-peak amplitude for the higher sound intensity. On a descriptive level, the 80 dB HL stimulation yielded more activated voxels in fMRI and stronger activations. This effect was pronounced over the right hemisphere. Our results suggest that low-noise sequences might be advantageous for the examination of auditory processing in simultaneous EEG and fMRI recordings.

  20. Source of level dependent minima in rabbit distortion product otoacoustic emissions

    PubMed Central

    Fahey, P. F.; Stagner, B. B.; Martin, G. K.

    2008-01-01

    Sharp level dependent minima (commonly called nulls or notches) in the distortion product otoacoustic emissions (DPOAEs) have been postulated to be due to two different mechanisms. It is shown here that the level dependent nulls in rabbit 2f1−f2 DPOAEs carry the signature of the mixing of a third order nonlinear term with a fifth order nonlinear term. This suggests that the minima are not due to the mixing of signals from two different physical sites of origin, but rather are due to the nature of the nonlinearity itself. Model simulations show that null production is indifferent to several properties of nonlinear input∕output functions. PMID:19206797

  1. The study of pain with blood oxygen level dependent functional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Ibinson, James W.

    Using blood oxygen level dependent functional magnetic resonance imaging (BOLD FMRI), the brain areas activated by pain were studied. These initial studies led to interesting new findings about the body's response to pain and to the refinement of one method used in FMRI analysis for correction of physiologic noise (signal fluctuations caused by the cyclic and non-cyclic changes in the cardiovascular and respiratory status of the body). In the first study, evidence was provided suggesting that the multiple painful stimulations used in typical pain FMRI block designs may cause attenuation over time of the BOLD signal within activated areas. The effect this may have on pain investigations using multiple tasks has not been previously investigated. The demonstrated BOLD attenuation seems unique to pain studies. Several possible explanations exist, but two of the most likely are neural activity modulation by descending pain inhibitory mechanisms and changing hemodynamics caused by a physiologic response to pain. The second study began the investigation of hemodynamics by monitoring the physiologic response to pain for eight subjects in two phases. Phase one used a combination of standard operating suite monitors and research equipment to characterizing the physiologic response to pain. Phase two collected magnetic resonance quantitative flow images during painful nerve stimulation to test for changes in global cerebral blood flow. It is well established that changes in respiration and global blood flow can affect the BOLD response, leading to the final investigation of this dissertation. The brain activation induced by pain for the same eight subjects used in the physiologic response experiments described above was then studied by BOLD FMRI. By including the respiration signal and end-tidal carbon dioxide levels in the analysis of the images, the quantification and removal of image intensity variations correlated to breathing and end-tidal carbon dioxide changes could be

  2. Quantitative analysis of the postcontractile blood-oxygenation-level-dependent (BOLD) effect in skeletal muscle

    PubMed Central

    Towse, Theodore F.; Slade, Jill M.; Ambrose, Jeffrey A.; DeLano, Mark C.

    2011-01-01

    Previous studies show that transient increases in both blood flow and magnetic resonance image signal intensity (SI) occur in human muscle after brief, single contractions, and that the SI increases are threefold larger in physically active compared with sedentary subjects. This study examined the relationship between these transient changes by measuring anterior tibial artery flow (Doppler ultrasound), anterior muscle SI (3T, one-shot echo-planar images, TR/TE = 1,000/35), and muscle blood volume and hemoglobin saturation [near-infrared spectroscopy (NIRS)] in the same subjects after 1-s-duration maximum isometric ankle dorsiflexion contractions. Arterial flow increased to a peak 5.9 ± 0.7-fold above rest (SE, n = 11, range 2.6–10.2) within 7 s and muscle SI increased to a peak 2.7 ± 0.6% (range 0.0–6.0%) above rest within 12 s after the contractions. The peak postcontractile SI change was significantly correlated with both peak postcontractile flow (r = 0.61, n = 11) and with subject activity level (r = 0.63, n = 10) estimated from 7-day accelerometer recordings. In a subset of 7 subjects in which NIRS data acquisition was successful, the peak magnitude of the postcontractile SI change agreed well with SI calculated from the NIRS blood volume and saturation changes (r = 0.80, slope = 1.02, intercept = 0.16), confirming the blood-oxygenation-level-dependent (BOLD) mechanism underlying the SI change. The magnitudes of postcontractile changes in blood saturation and SI were reproduced by a simple one-compartment muscle vascular model that incorporated the observed pattern of postcontractile flow, and which assumed muscle O2 consumption peaks within 2 s after a brief contraction. The results show that muscle postcontractile BOLD SI changes depend critically on the balance between O2 delivery and O2 consumption, both of which can be altered by chronic physical activity. PMID:21330621

  3. Increased regional homogeneity of blood oxygen level-dependent signals in occipital cortex of early blind individuals.

    PubMed

    Liu, Chong; Liu, Yong; Li, Weilan; Wang, Dawei; Jiang, Tianzi; Zhang, Yunting; Yu, Chunshui

    2011-03-09

    Although resting-state functional magnetic resonance imaging has shown altered functional connectivity between visual and other brain areas in the early blind individuals, it cannot answer which brain area's local activities are changed. In this study, regional homogeneity, a measure of the homogeneity of the local blood oxygen level-dependent signals, was used for the first time to investigate the changes in the resting-state brain activity in the early blind individuals. Compared with age-matched and sex-matched sighted individuals, the early blind individuals showed increased regional homogeneity only in the occipital areas, which might be explained by the abnormal cortical development and/or experience-dependent plasticity, resulted from an early visual deprivation.

  4. Blood oxygenation level dependent functional magnetic resonance imaging: current and potential uses in obstetrics and gynaecology

    PubMed Central

    Vincent, K; Moore, J; Kennedy, S; Tracey, I

    2008-01-01

    Blood-oxygenation-level-dependent functional magnetic resonance imaging is a noninvasive technique that has become increasingly popular in the neurosciences. It measures the proportion of oxygenated haemoglobin in specific areas of the brain, mirroring blood flow and therefore function. Here we review how the findings from functional studies impact on areas of gynaecological practice as diverse as chronic pain, continence, and premenstrual dysphoric disorder. Finally we review some of the more novel applications of the technique, such as imaging of pelvic floor function and the effects of hypoxia on the fetus. PMID:19076956

  5. Architecture-Level Dependability Analysis of a Medical Decision Support System

    SciTech Connect

    Pullum, Laura L; Symons, Christopher T; Patton, Robert M; Beckerman, Barbara G

    2010-01-01

    Recent advances in techniques such as image analysis, text analysis and machine learning have shown great potential to assist physicians in detecting and diagnosing health issues in patients. In this paper, we describe the approach and findings of an architecture-level dependability analysis for a mammography decision support system that incorporates these techniques. The goal of the research described in this paper is to provide an initial understanding of the dependability issues, particularly the potential failure modes and severity, in order to identify areas of potential high risk. The results will guide design decisions and provide the basis of a dependability and performance evaluation program.

  6. Strain-Level Dependent Nonequilibrium Anisotropic Viscoelasticity: Application to the Abdominal Muscle.

    PubMed

    Latorre, Marcos; Montáns, Francisco J

    2017-10-01

    Soft connective tissues sustain large strains of viscoelastic nature. The rate-independent component is frequently modeled by means of anisotropic hyperelastic models. The rate-dependent component is usually modeled through linear rheological models or quasi-linear viscoelastic (QLV) models. These viscoelastic models are unable, in general, to capture the strain-level dependency of the viscoelastic properties present in many viscoelastic tissues. In linear viscoelastic models, strain-level dependency is frequently accounted for by including the dependence of multipliers of Prony series on strains through additional evolution laws, but the determination of the material parameters is a difficult task and the obtained accuracy is usually not sufficient. In this work, we introduce a model for fully nonlinear viscoelasticity in which the instantaneous and quasi-static behaviors are exactly captured and the relaxation curves are predicted to a high accuracy. The model is based on a fully nonlinear standard rheological model and does not necessitate optimization algorithms to obtain material parameters. Furthermore, in contrast to most models used in modeling the viscoelastic behavior of soft tissues, it is valid for the large deviations from thermodynamic equilibrium typically observed in soft tissues.

  7. Anatomical, blood oxygenation level-dependent, and blood flow MRI of nonhuman primate (baboon) retina.

    PubMed

    Zhang, Yi; Wey, Hsiao-Ying; San Emeterio Nateras, Oscar; Peng, Qi; De La Garza, Bryan H; Duong, Timothy Q

    2011-08-01

    The goal of this study was to demonstrate high-resolution anatomical, blood oxygenation level-dependent, and blood flow MRI on large nonhuman primate retinas using a 3-Tesla clinical scanner as a first step toward translation. Baboon was chosen because of its evolutionary similarity to human. Anesthetized preparation, free of eye-movement artifacts, was used to evaluate clinical scanner hardware feasibility and optimize multimodal protocols for retinal MRI. Anatomical MRI (0.1×0.2×2.0 mm3) before contrast-agent injection detected three alternating bright-dark-bright layers. The hyperintense inner strip nearest to the vitreous was enhanced by an intravascular contrast agent, which likely included the ganglion and bipolar cell layer and the embedded retinal vessels. The hypointense middle strip showed no contrast enhancement, which likely included the avascular outer unclear layer and photoreceptor segments. The hyperintense outer strip showed contrast enhancement, which likely corresponded to the choroid vascular layer. In the posterior retina, the total thickness including the choroid was 617±101 μm (±standard deviation, n=7). Blood oxygenation level-dependent functional MRI (0.3×0.6×2.0 mm3) of oxygen inhalation relative to air increased the signals by 6.5±1.4%. Basal blood flow (2×2×2 mm3) was 83±30 mL/100 g/min (air), and hypercapnia increased blood flow by 25±9% (P<0.05). This study demonstrates multimodal MRI to image anatomy, physiology, and function on large nonhuman primate retinas using a clinical scanner, offering encouraging data to explore human applications. Copyright © 2011 Wiley-Liss, Inc.

  8. Neuronal synchrony and the relation between the blood-oxygen-level dependent response and the local field potential

    PubMed Central

    Nguyen, Mai; Winawer, Jonathan

    2017-01-01

    The most widespread measures of human brain activity are the blood-oxygen-level dependent (BOLD) signal and surface field potential. Prior studies report a variety of relationships between these signals. To develop an understanding of how to interpret these signals and the relationship between them, we developed a model of (a) neuronal population responses and (b) transformations from neuronal responses into the functional magnetic resonance imaging (fMRI) BOLD signal and electrocorticographic (ECoG) field potential. Rather than seeking a transformation between the two measures directly, this approach interprets each measure with respect to the underlying neuronal population responses. This model accounts for the relationship between BOLD and ECoG data from human visual cortex in V1, V2, and V3, with the model predictions and data matching in three ways: across stimuli, the BOLD amplitude and ECoG broadband power were positively correlated, the BOLD amplitude and alpha power (8–13 Hz) were negatively correlated, and the BOLD amplitude and narrowband gamma power (30–80 Hz) were uncorrelated. The two measures provide complementary information about human brain activity, and we infer that features of the field potential that are uncorrelated with BOLD arise largely from changes in synchrony, rather than level, of neuronal activity. PMID:28742093

  9. Altered blood oxygen level-dependent signal variability in chronic post-traumatic stress disorder during symptom provocation

    PubMed Central

    Ke, Jun; Zhang, Li; Qi, Rongfeng; Xu, Qiang; Li, Weihui; Hou, Cailan; Zhong, Yuan; Zhang, Zhiqiang; He, Zhong; Li, Lingjiang; Lu, Guangming

    2015-01-01

    Background Recent research suggests that variability in brain signal provides important information about brain function in health and disease. However, it is unknown whether blood oxygen level-dependent (BOLD) signal variability is altered in post-traumatic stress disorder (PTSD). We aimed to identify the BOLD signal variability changes of PTSD patients during symptom provocation and compare the brain patterns of BOLD signal variability with those of brain activation. Methods Twelve PTSD patients and 14 age-matched controls, who all experienced a mining accident, underwent clinical assessment as well as fMRI scanning while viewing trauma-related and neutral pictures. BOLD signal variability and brain activation were respectively examined with standard deviation (SD) and general linear model analysis, and compared between the PTSD and control groups. Multiple regression analyses were conducted to explore the association between PTSD symptom severity and these two brain measures across all subjects as well as in the PTSD group. Results PTSD patients showed increased activation in the middle occipital gyrus compared with controls, and an inverse correlation was found between PTSD symptom severity and brain activation in the hippocampus and anterior cingulate cortex/medial prefrontal cortex. Brain variability analysis revealed increased SD in the insula, anterior cingulate cortex/medial prefrontal cortex, and vermis, and decreased SD in the parahippocapal gyrus, dorsolateral prefrontal cortex, somatosensory cortex, and striatum. Importantly, SD alterations in several regions were found in both traumatic and neutral conditions and were stratified by PTSD symptom severity. Conclusion BOLD signal variability may be a reliable and sensitive biomarker of PTSD, and combining brain activation and brain variability analysis may provide complementary insight into the neural basis of this disorder. PMID:26229476

  10. Reproducibility of blood oxygen level-dependent signal changes with end-tidal carbon dioxide alterations.

    PubMed

    Dengel, Donald R; Evanoff, Nicholas G; Marlatt, Kara L; Geijer, Justin R; Mueller, Bryon A; Lim, Kelvin O

    2016-03-02

    Hypercapnia has been utilized as a stimulus to elicit changes in cerebral blood flow (CBF). However, in many instances it has been delivered in a non-controlled method that is often difficult to reproduce. The purpose of this study was to examine the within- and between-visit reproducibility of blood oxygen level-dependent (BOLD) signal changes to an iso-oxic square wave alteration in end-tidal carbon dioxide partial pressure (Pet CO2 ). Two 3-Tesla (3T) MRI scans were performed on the same visit, with two square wave alterations administered per scan. The protocol was repeated on a separate visit with minimum of 3 days between scanning sessions. Pet CO2 was altered to stimulate changes in cerebral vascular reactivity (CVR), while Pet O2 was held constant. Eleven subjects (six females; mean age 26·5 ± 5·7 years) completed the full testing protocol. Excellent within-visit square wave reproducibility (ICC > 0·75) was observed. Similarly, square waves were reproducible between scanning sessions (ICC > 0·7). This study demonstrates BOLD signal changes in response to alterations in Pet CO2 are reproducible both within- and between-visit MRI scans.

  11. Blood Oxygenation Level-Dependent MRI to Assess Renal Oxygenation in Renal Diseases: Progresses and Challenges

    PubMed Central

    Pruijm, Menno; Milani, Bastien; Burnier, Michel

    2017-01-01

    BOLD-MRI (blood oxygenation-level dependent magnetic resonance imaging) allows non-invasive measurement of renal tissue oxygenation in humans, without the need for contrast products. BOLD-MRI uses the fact that magnetic properties of hemoglobin depend of its oxygenated state:: the higher local deoxyhemoglobin, the higher the so called apparent relaxation rate R2* (sec−1), and the lower local tissue oxygen content. Several factors other than deoxyhemoglobin (such as hydration status, dietary sodium intake, and susceptibility effects) influence the BOLD signal, and need to be taken into account when interpreting results. The last 5 years have witnessed important improvements in the standardization of these factors, and the appearance of new, highly reproducible analysis techniques of BOLD-images, that are reviewed in this article. Using these new BOLD-MRI analysis techniques, it has recently been shown that persons suffering from chronic kidney diseases (CKD) have lower cortical oxygenation than normotensive controls, thus confirming the chronic hypoxia hypothesis. The acute alterations in R2* after the administration of furosemide are smaller in CKD, and represent an estimate of the oxygen-dependent tubular transport of sodium. BOLD-MRI-alone or in combination with other functional MRI methods- can be used to monitor the renal effects of drugs, and is increasingly used in the preclinical setting. The near future will tell whether or not BOLD-MRI represents a new tool to predict renal function decline an adverse renal outcome. PMID:28105019

  12. Level dependence of the nonlinear-distortion component of distortion-product otoacoustic emissions in humans.

    PubMed

    Zelle, Dennis; Thiericke, John P; Dalhoff, Ernst; Gummer, Anthony W

    2015-12-01

    Distortion-product otoacoustic emissions (DPOAEs) emerge when presenting two primary tones with different frequencies f1 and f2 to the cochlea and are commonly used in diagnosis and research to evaluate the functional state of the cochlea. Optimal primary-tone stimulus levels accounting for the different level dependencies of the traveling-wave amplitudes of the two primary tones near the f2-tonotopic place on the basilar membrane are often used to maximize DPOAE amplitudes. However, parameters defining the optimal levels can be affected by wave interference between the nonlinear-distortion and coherent-reflection components of the DPOAE. Here, the components were separated in the time domain using a pulsed stimulus paradigm and optimal levels determined. Based on the amplitude dependence of the nonlinear-distortion components on primary-tone stimulus levels, level parameters yielding maximum DPOAE amplitudes were derived for six normal-hearing adults and compared to data recorded with continuous two-tone stimulation. The level parameters resulting from analysis of the nonlinear-distortion components show dependence on stimulus frequency and small standard deviations. DPOAE input/output functions derived for optimal levels exhibit larger slopes, wider dynamic range and less variability across subjects than those derived for conventional stimulus and analysis conditions, potentially increasing their reliability and sensitivity for assessing cochlea function.

  13. Blood oxygen-level dependent functional assessment of cerebrovascular reactivity: Feasibility for intraoperative 3 Tesla MRI.

    PubMed

    Fierstra, Jorn; Burkhardt, Jan-Karl; van Niftrik, Christiaan Hendrik Bas; Piccirelli, Marco; Pangalu, Athina; Kocian, Roman; Neidert, Marian Christoph; Valavanis, Antonios; Regli, Luca; Bozinov, Oliver

    2017-02-01

    To assess the feasibility of functional blood oxygen-level dependent (BOLD) MRI to evaluate intraoperative cerebrovascular reactivity (CVR) at 3 Tesla field strength. Ten consecutive neurosurgical subjects scheduled for a clinical intraoperative MRI examination were enrolled in this study. In addition to the clinical protocol a BOLD sequence was implemented with three cycles of 44 s apnea to calculate CVR values on a voxel-by-voxel basis throughout the brain. The CVR range was then color-coded and superimposed on an anatomical volume to create high spatial resolution CVR maps. Ten subjects (mean age 34.8 ± 13.4; 2 females) uneventfully underwent the intraoperative BOLD protocol, with no complications occurring. Whole-brain CVR for all subjects was (mean ± SD) 0.69 ± 0.42, whereas CVR was markedly higher for tumor subjects as compared to vascular subjects, 0.81 ± 0.44 versus 0.33 ± 0.10, respectively. Furthermore, color-coded functional maps could be robustly interpreted for a whole-brain assessment of CVR. We demonstrate that intraoperative BOLD MRI is feasible in creating functional maps to assess cerebrovascular reactivity throughout the brain in subjects undergoing a neurosurgical procedure. Magn Reson Med 77:806-813, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  14. Deciphering phonemes from syllables in blood oxygenation level-dependent signals in human superior temporal gyrus.

    PubMed

    Zhang, Qingtian; Hu, Xiaolin; Luo, Huan; Li, Jianmin; Zhang, Xiaolu; Zhang, Bo

    2016-03-01

    Linguistic units such as phonemes and syllables are important for speech perception. How the brain encodes these units is not well understood. Many neuroimaging studies have found distinct representations of consonant-vowel syllables that shared one phoneme and differed in the other phoneme (e.g. /ba/ and /da/), but it is unclear whether this discrimination ability is due to the neural coding of phonemes or syllables. We combined functional magnetic resonance imaging with multivariate pattern analysis to explore this question. Subjects listened to nine Mandarin syllables in a consonant-vowel form. We successfully decoded phonemes from the syllables based on the blood oxygenation level-dependent signals in the superior temporal gyrus (STG). Specifically, a classifier trained on the cortical patterns elicited by a set of syllables, which contained two phonemes, could distinguish the cortical patterns elicited by other syllables that contained the two phonemes. The results indicated that phonemes have unique representations in the STG. In addition, there was a categorical effect, i.e. the cortical patterns of consonants were similar, and so were the cortical patterns of vowels. Further analysis showed that phonemes exhibited stronger encoding specificity in the mid-STG than in the anterior STG.

  15. Cortical depth-specific microvascular dilation underlies laminar differences in blood oxygenation level-dependent functional MRI signal

    PubMed Central

    Tian, Peifang; Teng, Ivan C.; May, Larry D.; Kurz, Ronald; Lu, Kun; Scadeng, Miriam; Hillman, Elizabeth M. C.; De Crespigny, Alex J.; D’Arceuil, Helen E.; Mandeville, Joseph B.; Marota, John J. A.; Rosen, Bruce R.; Liu, Thomas T.; Boas, David A.; Buxton, Richard B.; Dale, Anders M.; Devor, Anna

    2010-01-01

    Changes in neuronal activity are accompanied by the release of vasoactive mediators that cause microscopic dilation and constriction of the cerebral microvasculature and are manifested in macroscopic blood oxygenation level-dependent (BOLD) functional MRI (fMRI) signals. We used two-photon microscopy to measure the diameters of single arterioles and capillaries at different depths within the rat primary somatosensory cortex. These measurements were compared with cortical depth-resolved fMRI signal changes. Our microscopic results demonstrate a spatial gradient of dilation onset and peak times consistent with “upstream” propagation of vasodilation toward the cortical surface along the diving arterioles and “downstream” propagation into local capillary beds. The observed BOLD response exhibited the fastest onset in deep layers, and the “initial dip” was most pronounced in layer I. The present results indicate that both the onset of the BOLD response and the initial dip depend on cortical depth and can be explained, at least in part, by the spatial gradient of delays in microvascular dilation, the fastest response being in the deep layers and the most delayed response in the capillary bed of layer I. PMID:20696904

  16. Antihistamine induced blood oxygenation level dependent response changes related to visual processes during sensori-motor performance.

    PubMed

    van Ruitenbeek, Peter; Vermeeren, Annemiek; Mehta, Mitul Ashok; Drexler, Eva Isabell; Riedel, Willem Jan

    2014-07-01

    The histaminergic involvement in selective processes underlying its role in human sensori-motor performance is largely unknown. Recently, selective effects of central H₁-inverse agonism on sensory visual processes were observed in electrophysiological--but not behavioral data; a discrepancy suggested to result from speeded response-choice related processes. This study attempts to establish the effects on visual processes and identify putative compensatory mechanisms related to increased visual and response-choice task demands by assessing H₁-inverse agonism induced changes in blood oxygenation level dependent (BOLD) response. Twelve participants received oral doses of dexchlorpheniramine 4 mg, lorazepam 1 mg, and placebo in a three-way crossover designed study. Brain activity was assessed for choice reaction time task performance in a 3 T magnetic resonance scanner 2 h after drug administration. Participants responded with their left or right hand and index or middle finger as indicated by the laterality of stimulus presentation and identity of the stimulus, respectively. Stimuli were intact or visually degraded and responses were compatible or incompatible with the laterality of stimulus presentation. Both dexchlorpheniramine and lorazepam affected the BOLD response in the occipital cortex indicating affected visual information processing. Dexchlorpheniramine decreased BOLD response in the dorsal precuneus and left precentral gyrus as part of a motor network, which however might not be interpreted as a compensatory mechanism, but may be the upstream consequence of impaired visual processing. Copyright © 2013 Wiley Periodicals, Inc.

  17. Stabilities of negative correlations between blood oxygen level-dependent signals associated with sensory and motor cortices.

    PubMed

    Tian, Lixia; Jiang, Tianzi; Liang, Meng; Li, Xiaobo; He, Yong; Wang, Kun; Cao, Bingli; Jiang, Tao

    2007-07-01

    Compared with positive correlations, negative correlations of blood oxygen level-dependent (BOLD) signals (NCOBSs) have been much less studied. In most related studies, the NCOBSs have been accepted as stable without further consideration. To investigate the stabilities of NCOBSs associated with the auditory, motor, and visual cortices, we evaluated the negative correlation maps of each brain region under different "task-backgrounds" within the same subject-group, as well as within different subject-groups during a conscious resting state. These "task-backgrounds" refer to tasks not expected to activate the specific ROI under consideration and are in some sense analogous to "resting states." We found that the negative correlation maps of the motor and visual cortices were quite variable between either different task-backgrounds or different subject-groups, whereas those of the auditory cortex exhibited some similarities. These results indicate that the NCOBSs associated with the motor and visual cortices were unstable both under task-backgrounds and during the conscious resting state. The auditory cortex tended to have stable NCOBSs during these "resting states" (but scanner noise could make the auditory cortex "less resting"). This study highlights the importance of paying attention to the influence of the stabilities of NCOBSs in related studies and establishes the need for further studies on NCOBSs. Copyright 2007 Wiley-Liss, Inc.

  18. Octopus visual system: a functional MRI model for detecting neuronal electric currents without a blood-oxygen-level-dependent confound.

    PubMed

    Jiang, Xia; Lu, Hanbing; Shigeno, Shuichi; Tan, Li-Hai; Yang, Yihong; Ragsdale, Clifton W; Gao, Jia-Hong

    2014-11-01

    Despite the efforts that have been devoted to detecting the transient magnetic fields generated by neuronal firing, the conclusion that a functionally relevant signal can be measured with MRI is still controversial. For human studies of neuronal current MRI (nc-MRI), the blood-oxygen-level-dependent (BOLD) effect remains an irresolvable confound. For tissue studies where hemoglobin is removed, natural sensory stimulation is not possible. This study investigates the feasibility of detecting a physiologically induced nc-MRI signal in vivo in a BOLD-free environment. The cephalopod mollusc Octopus bimaculoides has vertebrate-like eyes, large optic lobes (OLs), and blood that does not contain hemoglobin. Visually evoked potentials were measured in the octopus retina and OL by electroretinogram and local field potential. nc-MRI scans were conducted at 9.4 Tesla to capture these activities. Electrophysiological recording detected strong responses in the retina and OL in vivo; however, nc-MRI failed to demonstrate any statistically significant signal change with a detection threshold of 0.2° for phase and 0.2% for magnitude. Experiments in a dissected eye-OL preparation yielded similar results. These findings in a large hemoglobin-free nervous system suggest that sensory evoked neuronal magnetic fields are too weak for direct detection with current MRI technology. Copyright © 2013 Wiley Periodicals, Inc.

  19. Dissociated lateralization of transient and sustained blood oxygen level-dependent signal components in human primary auditory cortex.

    PubMed

    Lehmann, Christoph; Herdener, Marcus; Schneider, Peter; Federspiel, Andrea; Bach, Dominik R; Esposito, Fabrizio; di Salle, Francesco; Scheffler, Klaus; Kretz, Robert; Dierks, Thomas; Seifritz, Erich

    2007-02-15

    Among other auditory operations, the analysis of different sound levels received at both ears is fundamental for the localization of a sound source. These so-called interaural level differences, in animals, are coded by excitatory-inhibitory neurons yielding asymmetric hemispheric activity patterns with acoustic stimuli having maximal interaural level differences. In human auditory cortex, the temporal blood oxygen level-dependent (BOLD) response to auditory inputs, as measured by functional magnetic resonance imaging (fMRI), consists of at least two independent components: an initial transient and a subsequent sustained signal, which, on a different time scale, are consistent with electrophysiological human and animal response patterns. However, their specific functional role remains unclear. Animal studies suggest these temporal components being based on different neural networks and having specific roles in representing the external acoustic environment. Here we hypothesized that the transient and sustained response constituents are differentially involved in coding interaural level differences and therefore play different roles in spatial information processing. Healthy subjects underwent monaural and binaural acoustic stimulation and BOLD responses were measured using high signal-to-noise-ratio fMRI. In the anatomically segmented Heschl's gyrus the transient response was bilaterally balanced, independent of the side of stimulation, while in opposite the sustained response was contralateralized. This dissociation suggests a differential role at these two independent temporal response components, with an initial bilateral transient signal subserving rapid sound detection and a subsequent lateralized sustained signal subserving detailed sound characterization.

  20. Blood oxygenation level-dependent (BOLD) functional MRI of visual stimulation in the rat retina at 11.7 T.

    PubMed

    De La Garza, Bryan H; Muir, Eric R; Li, Guang; Shih, Yen-Yu I; Duong, Timothy Q

    2011-02-01

    Although optically based imaging techniques provide valuable functional and physiological information of the retina, they are mostly limited to the probing of the retinal surface and require an unobstructed light path. MRI, in contrast, could offer physiological and functional data without depth limitation. Blood oxygenation level-dependent functional MRI (BOLD fMRI) of the thin rat retina is, however, challenging because of the need for high spatial resolution, and the potential presence of eye movement and susceptibility artifacts. This study reports a novel application of high-resolution (111 × 111 × 1000 µm(3)) BOLD fMRI of visual stimulation in the anesthetized rat retina at 11.7 T. A high-field MRI scanner was utilized to improve the signal-to-noise ratio, spatial resolution and BOLD sensitivity. Visual stimuli (8 Hz diffuse achromatic light) robustly increased BOLD responses in the retina [5.0 ± 0.8% from activated pixels and 3.1 ± 1.1% from the whole-retina region of interest (mean ± SD), n = 12 trials on six rats, p < 0.05 compared with baseline]. Some activated pixels were detected surrounding the pupil and ciliary muscle because of accommodation reflex to visual stimuli, and were reduced with atropine and phenylephrine eye drops. BOLD fMRI scans without visual stimulations showed no significantly activated pixels (whole-retina BOLD changes were 0.08 ± 0.34%, n = 6 trials on five rats, not statistically different from baseline, p > 0.05). BOLD fMRI of visual stimulation has the potential to provide clinically relevant data to probe hemodynamic neurovascular coupling and dysfunction of the retina with depth resolution. Copyright © 2010 John Wiley & Sons, Ltd.

  1. Characterizing the Blood Oxygen Level-Dependent Fluctuations in Musculoskeletal Tumours Using Functional Magnetic Resonance Imaging

    PubMed Central

    Duan, Li-Sha; Wang, Meng-Jun; Sun, Feng; Zhao, Zhen-Jiang; Xing, Mei; Zang, Yu-Feng; Louis, Steven; Cui, Sheng-Jie; Cui, Jian-Ling; Zhang, Han

    2016-01-01

    This study characterized the blood oxygen level-dependent (BOLD) fluctuations in benign and malignant musculoskeletal tumours via power spectrum analyses in pre-established low-frequency bands. BOLD MRI and T1-weighted imaging (T1WI) were collected for 52 patients with musculoskeletal tumours. Three ROIs were drawn on the T1WI image in the tumours’ central regions, peripheral regions and neighbouring tissue. The power spectrum of the BOLD within each ROI was calculated and divided into the following four frequency bands: 0.01–0.027 Hz, 0.027–0.073 Hz, 0.073–0.198 Hz, and 0.198–0.25 Hz. ANOVA was conducted for each frequency band with the following two factors: the location of the region of interest (LoR, three levels: tumour “centre”, “peripheral” and “healthy tissue”) and tumour characteristic (TC, two levels: “malignant” and “benign”). There was a significant main effect of LoR in the frequencies of 0.073–0.198 Hz and 0.198–0.25 Hz. These data were further processed with post-hoc pair-wise comparisons. BOLD fluctuations at 0.073–0.198 Hz were stronger in the peripheral than central regions of the malignant tumours; however, no such difference was observed for the benign tumours. Our findings provide evidence that the BOLD signal fluctuates with spatial heterogeneity in malignant musculoskeletal tumours at the frequency band of 0.073–0.198 Hz. PMID:27845359

  2. Negative blood oxygenation level dependent homunculus and somatotopic information in primary motor cortex and supplementary motor area

    PubMed Central

    Zeharia, Noa; Hertz, Uri; Flash, Tamar; Amedi, Amir

    2012-01-01

    A crucial attribute in movement encoding is an adequate balance between suppression of unwanted muscles and activation of required ones. We studied movement encoding across the primary motor cortex (M1) and supplementary motor area (SMA) by inspecting the positive and negative blood oxygenation level-dependent (BOLD) signals in these regions. Using periodic and event-related experiments incorporating the bilateral/axial movements of 20 body parts, we report detailed mototopic imaging maps in M1 and SMA. These maps were obtained using phase-locked analysis. In addition to the positive BOLD, significant negative BOLD was detected in M1 but not in the SMA. The negative BOLD spatial pattern was neither located at the ipsilateral somatotopic location nor randomly distributed. Rather, it was organized somatotopically across the entire homunculus and inversely to the positive BOLD, creating a negative BOLD homunculus. The neuronal source of negative BOLD is unclear. M1 provides a unique system to test whether the origin of negative BOLD is neuronal, because different arteries supply blood to different regions in the homunculus, ruling out blood-stealing explanations. Finally, multivoxel pattern analysis showed that positive BOLD in M1 and SMA and negative BOLD in M1 contain somatotopic information, enabling prediction of the moving body part from inside and outside its somatotopic location. We suggest that the neuronal processes underlying negative BOLD participate in somatotopic encoding in M1 but not in the SMA. This dissociation may emerge because of differences in the activity of these motor areas associated with movement suppression. PMID:23086164

  3. Effects of aging on cerebral blood flow, oxygen metabolism, and blood oxygenation level dependent responses to visual stimulation.

    PubMed

    Ances, Beau M; Liang, Christine L; Leontiev, Oleg; Perthen, Joanna E; Fleisher, Adam S; Lansing, Amy E; Buxton, Richard B

    2009-04-01

    Calibrated functional magnetic resonance imaging (fMRI) provides a noninvasive technique to assess functional metabolic changes associated with normal aging. We simultaneously measured both the magnitude of the blood oxygenation level dependent (BOLD) and cerebral blood flow (CBF) responses in the visual cortex for separate conditions of mild hypercapnia (5% CO(2)) and a simple checkerboard stimulus in healthy younger (n = 10, mean: 28-years-old) and older (n = 10, mean: 53-years-old) adults. From these data we derived baseline CBF, the BOLD scaling parameter M, the fractional change in the cerebral metabolic rate of oxygen consumption (CMRO(2)) with activation, and the coupling ratio n of the fractional changes in CBF and CMRO(2). For the functional activation paradigm, the magnitude of the BOLD response was significantly lower for the older group (0.57 +/- 0.07%) compared to the younger group (0.95 +/- 0.14%), despite the finding that the fractional CBF and CMRO(2) changes were similar for both groups. The weaker BOLD response for the older group was due to a reduction in the parameter M, which was significantly lower for older (4.6 +/- 0.4%) than younger subjects (6.5 +/- 0.8%), most likely reflecting a reduction in baseline CBF for older (41.7 +/- 4.8 mL/100 mL/min) compared to younger (59.6 +/- 9.1 mL/100 mL/min) subjects. In addition to these primary responses, for both groups the BOLD response exhibited a post-stimulus undershoot with no significant difference in this magnitude. However, the post-undershoot period of the CBF response was significantly greater for older compared to younger subjects. We conclude that when comparing two populations, the BOLD response can provide misleading reflections of underlying physiological changes. A calibrated approach provides a more quantitative reflection of underlying metabolic changes than the BOLD response alone.

  4. Negative blood oxygenation level dependent homunculus and somatotopic information in primary motor cortex and supplementary motor area.

    PubMed

    Zeharia, Noa; Hertz, Uri; Flash, Tamar; Amedi, Amir

    2012-11-06

    A crucial attribute in movement encoding is an adequate balance between suppression of unwanted muscles and activation of required ones. We studied movement encoding across the primary motor cortex (M1) and supplementary motor area (SMA) by inspecting the positive and negative blood oxygenation level-dependent (BOLD) signals in these regions. Using periodic and event-related experiments incorporating the bilateral/axial movements of 20 body parts, we report detailed mototopic imaging maps in M1 and SMA. These maps were obtained using phase-locked analysis. In addition to the positive BOLD, significant negative BOLD was detected in M1 but not in the SMA. The negative BOLD spatial pattern was neither located at the ipsilateral somatotopic location nor randomly distributed. Rather, it was organized somatotopically across the entire homunculus and inversely to the positive BOLD, creating a negative BOLD homunculus. The neuronal source of negative BOLD is unclear. M1 provides a unique system to test whether the origin of negative BOLD is neuronal, because different arteries supply blood to different regions in the homunculus, ruling out blood-stealing explanations. Finally, multivoxel pattern analysis showed that positive BOLD in M1 and SMA and negative BOLD in M1 contain somatotopic information, enabling prediction of the moving body part from inside and outside its somatotopic location. We suggest that the neuronal processes underlying negative BOLD participate in somatotopic encoding in M1 but not in the SMA. This dissociation may emerge because of differences in the activity of these motor areas associated with movement suppression.

  5. Measurement of renal tissue oxygenation with blood oxygen level-dependent MRI and oxygen transit modeling

    PubMed Central

    Morrell, Glen; Rusinek, Henry; Warner, Lizette; Vivier, Pierre-Hugues; Cheung, Alfred K.; Lerman, Lilach O.; Lee, Vivian S.

    2014-01-01

    Blood oxygen level-dependent (BOLD) MRI data of kidney, while indicative of tissue oxygenation level (Po2), is in fact influenced by multiple confounding factors, such as R2, perfusion, oxygen permeability, and hematocrit. We aim to explore the feasibility of extracting tissue Po2 from renal BOLD data. A method of two steps was proposed: first, a Monte Carlo simulation to estimate blood oxygen saturation (SHb) from BOLD signals, and second, an oxygen transit model to convert SHb to tissue Po2. The proposed method was calibrated and validated with 20 pigs (12 before and after furosemide injection) in which BOLD-derived tissue Po2 was compared with microprobe-measured values. The method was then applied to nine healthy human subjects (age: 25.7 ± 3.0 yr) in whom BOLD was performed before and after furosemide. For the 12 pigs before furosemide injection, the proposed model estimated renal tissue Po2 with errors of 2.3 ± 5.2 mmHg (5.8 ± 13.4%) in cortex and −0.1 ± 4.5 mmHg (1.7 ± 18.1%) in medulla, compared with microprobe measurements. After injection of furosemide, the estimation errors were 6.9 ± 3.9 mmHg (14.2 ± 8.4%) for cortex and 2.6 ± 4.0 mmHg (7.7 ± 11.5%) for medulla. In the human subjects, BOLD-derived medullary Po2 increased from 16.0 ± 4.9 mmHg (SHb: 31 ± 11%) at baseline to 26.2 ± 3.1 mmHg (SHb: 53 ± 6%) at 5 min after furosemide injection, while cortical Po2 did not change significantly at ∼58 mmHg (SHb: 92 ± 1%). Our proposed method, validated with a porcine model, appears promising for estimating tissue Po2 from renal BOLD MRI data in human subjects. PMID:24452640

  6. Age- and Level-Dependence of Fatty Infiltration in Lumbar Paravertebral Muscles of Healthy Volunteers.

    PubMed

    Crawford, R J; Filli, L; Elliott, J M; Nanz, D; Fischer, M A; Marcon, M; Ulbrich, E J

    2016-04-01

    Normative age-related decline in paravertebral muscle quality is important for reference to disease and risk identification in patients. We aimed to establish age- and vertebral level-dependence of paravertebral (multifidus and erector spinae) muscle volume and fat content in healthy adult volunteers. In this prospective study multifidus and erector spinae fat signal fraction and volume at lumbar levels L1-L5 were measured in 80 healthy volunteers (10 women and men per decade, 20-62 years of age) by 2-point Dixon 3T MR imaging. ANOVA with post hoc Bonferroni correction compared fat signal fraction and volume among subgroups. Pearson and Spearman analysis were used for correlations (P < .05). Fat signal fraction was higher in women (17.8% ± 10.7%) than men (14.7% ± 7.8%; P < .001) and increased with age. Multifidus and erector spinae volume was lower in women (565.4 ± 83.8 cm(3)) than in men (811.6 ± 98.9 cm(3); P < .001) and was age-independent. No differences in fat signal fraction were shown between the right and left paravertebral muscles or among the L1, L2, and L3 lumbar levels. The fat signal fraction was highest at L5 (women, 31.9% ± 9.3%; men, 25.7% ± 8.0%; P < .001). The fat signal fraction at L4 correlated best with total lumbar fat signal fraction (women, r = 0.95; men, r = 0.92, P < .001). Total fat signal fraction was higher in the multifidus compared with erector spinae muscles at L1-L4 for both sexes (P < .001). Lumbar paravertebral muscle fat content increases with aging, independent of volume, in healthy volunteers 20-62 years of age. Women, low lumbar levels, and the multifidus muscle are most affected. Further study examining younger and older subjects and the functional impact of fatty infiltrated paravertebral muscles are warranted. © 2016 by American Journal of Neuroradiology.

  7. Blood oxygenation level-dependent functional MRI signal turbulence caused by ultrahigh spatial resolution: numerical simulation and theoretical explanation

    PubMed Central

    Chen, Zikuan; Chen, Zeyuan; Calhoun, Vince

    2015-01-01

    High-spatial-resolution functional MRI (fMRI) can enhance image contrast and improve spatial specificity for brain activity mapping. As the voxel size is reduced, an irregular magnetic fieldmap will emerge as a result of less local averaging, and will lead to abnormal fMRI signal evolution with respect to the image acquisition TE. In this article, we report this signal turbulence phenomenon observed in simulations of ultrahigh-spatial-resolution blood oxygenation level-dependent (BOLD) fMRI (voxel size of less than 50 × 50 × 50 μm3). We present a four-level coarse-to-fine multiresolution BOLD fMRI signal simulation. Based on the statistical histogram of an intravoxel fieldmap, we reformulate the intravoxel dephasing summation (a form of Riemann sum) into a new formula that is a discrete Fourier transformation of the intravoxel fieldmap histogram (a form of Lebesgue sum). We interpret the BOLD signal formation by relating its magnitude (phase) to the even (odd) symmetry of the fieldmap histogram. Based on multiresolution BOLD signal simulation, we find that the signal turbulence mainly emerges at the vessel boundary, and that there are only a few voxels (less than 10%) in an ultrahigh-resolution image that reveal turbulence in the form of sparse point noise. Our simulation also shows that, for typical human brain imaging of the cerebral cortex with millimeter resolution, TE < 30 ms and B0 = 3 T, we are unlikely to observe BOLD signal turbulence. Overall, the main causes of voxel signal turbulence include a high spatial resolution, high field, long TE and large vessel. PMID:22927163

  8. Effects of Aging on Cerebral Blood Flow, Oxygen Metabolism, and Blood Oxygenation Level Dependent Responses to Visual Stimulation

    PubMed Central

    Ances, Beau M.; Liang, Christine L.; Leontiev, Oleg; Perthen, Joanna E.; Fleisher, Adam S.; Lansing, Amy E.; Buxton, Richard B.

    2010-01-01

    Calibrated functional magnetic resonance imaging (fMRI) provides a noninvasive technique to assess functional metabolic changes associated with normal aging. We simultaneously measured both the magnitude of the blood oxygenation level dependent (BOLD) and cerebral blood flow (CBF) responses in the visual cortex for separate conditions of mild hypercapnia (5% CO2) and a simple checkerboard stimulus in healthy younger (n = 10, mean: 28-years-old) and older (n = 10, mean: 53-years-old) adults. From these data we derived baseline CBF, the BOLD scaling parameter M, the fractional change in the cerebral metabolic rate of oxygen consumption (CMRO2) with activation, and the coupling ratio n of the fractional changes in CBF and CMRO2. For the functional activation paradigm, the magnitude of the BOLD response was significantly lower for the older group (0.57 ± 0.07%) compared to the younger group (0.95 ± 0.14%), despite the finding that the fractional CBF and CMRO2 changes were similar for both groups. The weaker BOLD response for the older group was due to a reduction in the parameter M, which was significantly lower for older (4.6 ± 0.4%) than younger subjects (6.5 ± 0.8%), most likely reflecting a reduction in baseline CBF for older (41.7 ± 4.8 mL/100 mL/min) compared to younger (59.6 ± 9.1 mL/100 mL/min) subjects. In addition to these primary responses, for both groups the BOLD response exhibited a post-stimulus undershoot with no significant difference in this magnitude. However, the post-undershoot period of the CBF response was significantly greater for older compared to younger subjects. We conclude that when comparing two populations, the BOLD response can provide misleading reflections of underlying physiological changes. A calibrated approach provides a more quantitative reflection of underlying metabolic changes than the BOLD response alone. PMID:18465743

  9. Functional and anatomical characterization of brown adipose tissue in heart failure with blood oxygen level dependent magnetic resonance.

    PubMed

    Panagia, Marcello; Chen, Yin-Ching Iris; Chen, Howard H; Ernande, Laura; Chen, Chan; Chao, Wei; Kwong, Kenneth; Scherrer-Crosbie, Marielle; Sosnovik, David E

    2016-07-01

    Recent studies have suggested that brown adipose tissue (BAT) plays an important role in obesity, insulin resistance and heart failure. The characterization of BAT in vivo, however, has been challenging. No technique to comprehensively image BAT anatomy and function has been described. Moreover, the impact on BAT of the neuroendocrine activation seen in heart failure has only recently begun to be evaluated in vivo. The aim of this study was to use MRI to characterize the impact of heart failure on the morphology and function of BAT. Mice subjected to permanent ligation of the left coronary artery were imaged with MRI 6 weeks later. T2 weighted MRI of BAT volume and blood oxygen level dependent MRI of BAT function were performed. T2 * maps of BAT were obtained at multiple time points before and after administration of the β3 adrenergic agonist CL 316 243 (CL). Blood flow to BAT was studied after CL injection using the flow alternating inversion recovery (FAIR) approach. Excised BAT tissue was analyzed for lipid droplet content and for uncoupling protein 1 (UCP1) mRNA expression. BAT volume was significantly lower in heart failure (51 ± 1 mm(3) versus 65 ± 3 mm(3) ; p < 0.05), and characterized by a reduction in lipid globules and a fourfold increase in UCP1 mRNA (p < 0.05). CL injection increased BAT T2 * in healthy animals but not in mice with heart failure (24 ± 4% versus 6 ± 2%; p < 0.01), consistent with an increase in flow in control BAT. This was confirmed by a significant difference in the FAIR response in BAT in control and heart failure mice. Heart failure results in the chronic activation of BAT, decreased BAT lipid stores and decreased BAT volume, and it is associated with a marked decrease in ability to respond to acute physiological stimuli. This may have important implications for substrate utilization and overall metabolic homeostasis in heart failure. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016

  10. The cadherin Flamingo mediates level-dependent interactions that guide photoreceptor target choice in Drosophila.

    PubMed

    Chen, Pei-Ling; Clandinin, Thomas R

    2008-04-10

    Quantitative differences in cadherin activity have been proposed to play important roles in patterning connections between pre- and postsynaptic neurons. However, no examples of such a function have yet been described, and the mechanisms that would allow such differences to direct growth cones to specific synaptic targets are unknown. In the Drosophila visual system, photoreceptors are genetically programmed to make a complex, stereotypic set of synaptic connections. Here we show that the atypical cadherin Flamingo functions as a short-range, homophilic signal, passing between specific R cell growth cones to influence their choice of postsynaptic partners. We find that individual growth cones are sensitive to differences in Flamingo activity through opposing interactions between neighboring cells and require these interactions to be balanced in order to extend along the appropriate trajectory.

  11. Axial level-dependent molecular and cellular mechanisms underlying the genesis of the embryonic neural plate.

    PubMed

    Kondoh, Hisato; Takada, Shinji; Takemoto, Tatsuya

    2016-06-01

    The transcription factor gene Sox2, centrally involved in neural primordial regulation, is activated by many enhancers. During the early stages of embryonic development, Sox2 is regulated by the enhancers N2 and N1 in the anterior neural plate (ANP) and posterior neural plate (PNP), respectively. This differential use of the enhancers reflects distinct regulatory mechanisms underlying the genesis of ANP and PNP. The ANP develops directly from the epiblast, triggered by nodal signal inhibition, and via the combined action of TFs SOX2, OTX2, POU3F1, and ZIC2, which promotes the the ANP development and inhibits other cell lineages. In contrast, the PNP is derived from neuromesodermal bipotential axial stem cells that develop into the neural plate when Sox2 is activated by the N1 enhancer, whereas they develop into the paraxial mesoderm when the N1 enhancer is repressed by the action of TBX6. The axial stem cells are maintained by the activity of WNT3a and T (Brachyury). However, at axial levels more anterior to the 8th somites (cervical levels), the development of both the neural plate and somite proceeds in the absence of WNT3a, T, or TBX6. These observations indicate that distinct molecular and cellular mechanisms determine neural plate genesis based on the axial level, and contradict the classical concept of the term "neural induction," which assumes a pan-neural plate mechanism.

  12. Compensating Level-Dependent Frequency Representation in Auditory Cortex by Synaptic Integration of Corticocortical Input

    PubMed Central

    Happel, Max F. K.; Ohl, Frank W.

    2017-01-01

    Robust perception of auditory objects over a large range of sound intensities is a fundamental feature of the auditory system. However, firing characteristics of single neurons across the entire auditory system, like the frequency tuning, can change significantly with stimulus intensity. Physiological correlates of level-constancy of auditory representations hence should be manifested on the level of larger neuronal assemblies or population patterns. In this study we have investigated how information of frequency and sound level is integrated on the circuit-level in the primary auditory cortex (AI) of the Mongolian gerbil. We used a combination of pharmacological silencing of corticocortically relayed activity and laminar current source density (CSD) analysis. Our data demonstrate that with increasing stimulus intensities progressively lower frequencies lead to the maximal impulse response within cortical input layers at a given cortical site inherited from thalamocortical synaptic inputs. We further identified a temporally precise intercolumnar synaptic convergence of early thalamocortical and horizontal corticocortical inputs. Later tone-evoked activity in upper layers showed a preservation of broad tonotopic tuning across sound levels without shifts towards lower frequencies. Synaptic integration within corticocortical circuits may hence contribute to a level-robust representation of auditory information on a neuronal population level in the auditory cortex. PMID:28046062

  13. A qualitative assessment of the performance of electronic, level-dependent earmuffs when used on firing ranges.

    PubMed

    Williams, Warwick

    2011-01-01

    A qualitative workplace trial was undertaken to examine the performance of sound restoration, level-dependent electronic hearing protectors (HPs) in a high impulsive noise environment using participants who were very experienced in the regular use of passive HPs. The results indicate that this type of HP is well accepted by experienced users, particularly so, by those who appreciate reliable communication while wearing the devices.

  14. Gender- and anxiety level-dependent effects of perinatal stress exposure on medial prefrontal cortex.

    PubMed

    Soztutar, Erdem; Colak, Ertugrul; Ulupinar, Emel

    2016-01-01

    Early life stress leads to psychopathological processes correlated with the predisposition of individuals. Prolonged development of the prefrontal cortex (PFC), playing a critical role in the cognition, personality and social behavior, makes it susceptible to adverse conditions. In this study, we evaluated the dendritic morphology of medial PFC neurons in rats subjected to perinatal stress exposure. Unbiased stereological counting methods showed that total number estimation of c-Fos (+) nuclei, indicating the neuronal activation upon stressful challenge, significantly increased in high anxious animals compared with low anxious and control groups, in both gender. Golgi-Cox staining of neurons displayed anxiety level- and sex-dependent reduction in the dendritic complexity and spine density of pyramidal neurons, especially in the stressed males. While the total length of dendrites were not correlational; density of spines, specifically the mushroom subtypes, showed a negative correlation with the anxiety level of stressed animals. These results suggest that medial PFC is a critical site of neural plasticity within the stressor controllability paradigm. Outcomes of early life stress might be predicted by analyzing the density and morphology of spines in the apical dendrites of pyramidal neurons in correlation with the anxiety-like behavior of animals. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Lithology- versus base level-dependent morphogenesis of the Hausruck - Kobernaußerwald range

    NASA Astrophysics Data System (ADS)

    Baumann, Sebastian; Robl, Jörg; Salcher, Bernhard; Prasicek, Günther; Keil, Melanie

    2016-04-01

    The Hausruck - Kobernaußerwald range has the highest relief in the Northern Molasse Basin in front of the Eastern Alps. The highest peaks of the range exceed an elevation of 800 m and are characterized by a local relief of about 400 m relative to the adjacent lowlands. The Hausruck - Kobernaußerwald range has never been glaciated and erosion is solely driven by fluvial incision and corresponding hillslope processes since the inversion of the Molasse Basin. Landslides are frequently observed at hillslopes in the Hausruck domain in the west but are completely missing in the Kobernaußerwald domain in the east. Recent tectonic activity like faulting has not been reported for that region and the stratigraphic record shows no evidence for tectonically induced discontinuities. The morphological expression of the western Kobernaußerwald and the eastern Hausruck apparently differ in their degree of erosional landscape decay with a gently incised western and deeply incised eastern domain. These domains correspond with two different lithological units of the Upper Freshwater Molasse: The simultaneously deposited western Kobernaußerwald Formation (Kobernaußerwald domain) and the eastern Ampfelwang Formation (Hausruck domain) are interpreted as sedimentary deposits of a fluvial fan in proximal and distal position, respectively, and show fining of the sedimentary record from west to east. The stratigraphic highest unit of the study region, the Hausruck Fm., consists of well consolidated fluvial gravels uniformly covering the hill tops of both domains. We used a high resolution LiDAR digital elevation model and performed a series of morphometric analyses to investigate the effects of different base levels and contrasting lithology on the topographic evolution of the Hausruck - Kobernaußerwald range. The analysis of longitudinal river profiles reveals that all channels independent from base level, bed rock and overall morphological expression are well graded with steep

  16. Functional multiparametric magnetic resonance imaging of the kidneys using blood oxygen level dependent and diffusion-weighted sequences.

    PubMed

    Giannarini, Gianluca; Kessler, Thomas M; Roth, Beat; Vermathen, Peter; Thoeny, Harriet C

    2014-08-01

    Little data are available on noninvasive magnetic resonance imaging based assessment of renal function during upper urinary tract obstruction. We determined whether functional multiparametric kidney magnetic resonance imaging could monitor the treatment response in cases of acute unilateral upper urinary tract obstruction. Between January 2008 and January 2010, 18 patients with acute unilateral upper urinary tract obstruction due to calculi were prospectively enrolled to undergo kidney magnetic resonance imaging with conventional, blood oxygen level dependent and diffusion-weighted sequences upon emergency hospital admission and after release of obstruction. We assessed functional imaging parameters of obstructed and contralateral unobstructed kidneys derived from blood oxygen level dependent (apparent spin relaxation rate) and diffusion-weighted (total apparent diffusion coefficient, pure diffusion coefficient and perfusion fraction) sequences during acute upper urinary tract obstruction and after its release. During acute obstruction the apparent spin relaxation rate and perfusion fraction were lower in the cortex (p=0.020 and 0.031) and medulla (p=0.012 and 0.190, respectively) of obstructed kidneys compared to contralateral unobstructed kidneys. After obstruction release the apparent spin relaxation rate and perfusion fraction increased in the cortex (p=0.016 and 0.004) and medulla (p=0.071 and 0.044, respectively) of formerly obstructed kidneys to values similar to those in contralateral kidneys. Total apparent diffusion coefficient and pure diffusion coefficient values did not significantly differ between obstructed and contralateral unobstructed kidneys during or after obstruction. In our patients with acute unilateral upper urinary tract obstruction due to calculi functional kidney magnetic resonance imaging using blood oxygen level dependent and diffusion-weighted sequences enabled us to monitor pathophysiological changes in obstructed kidneys during

  17. Megalophallus as a sequela of priapism in sickle cell anemia: use of blood oxygen level-dependent magnetic resonance imaging.

    PubMed

    Kassim, A A; Umans, H; Nagel, R L; Fabry, M E

    2000-09-01

    Priapism is a common complication of sickle cell anemia. We report a little known sequela of priapism: painless megalophallus, with significant penile enlargement. The patient had had an intense episode of priapism 9 years previously and his penis remained enlarged. Blood oxygen level-dependent magnetic resonance imaging revealed enlarged, hypoxic corpora cavernosa. Megalophallus probably resulted from permanent loss of elasticity of the tunica albuginea due to severe engorgement during the episode of priapism. This sequela needs to be recognized by physicians because no intervention is necessary and sexual function seems to remain intact.

  18. Evidence of cortical reorganization of language networks after stroke with subacute Broca's aphasia: a blood oxygenation level dependent-functional magnetic resonance imaging study

    PubMed Central

    Qiu, Wei-hong; Wu, Hui-xiang; Yang, Qing-lu; Kang, Zhuang; Chen, Zhao-cong; Li, Kui; Qiu, Guo-rong; Xie, Chun-qing; Wan, Gui-fang; Chen, Shao-qiong

    2017-01-01

    Aphasia is an acquired language disorder that is a common consequence of stroke. The pathogenesis of the disease is not fully understood, and as a result, current treatment options are not satisfactory. Here, we used blood oxygenation level-dependent functional magnetic resonance imaging to evaluate the activation of bilateral cortices in patients with Broca's aphasia 1 to 3 months after stroke. Our results showed that language expression was associated with multiple brain regions in which the right hemisphere participated in the generation of language. The activation areas in the left hemisphere of aphasia patients were significantly smaller compared with those in healthy adults. The activation frequency, volumes, and intensity in the regions related to language, such as the left inferior frontal gyrus (Broca's area), the left superior temporal gyrus, and the right inferior frontal gyrus (the mirror region of Broca's area), were lower in patients compared with healthy adults. In contrast, activation in the right superior temporal gyrus, the bilateral superior parietal lobule, and the left inferior temporal gyrus was stronger in patients compared with healthy controls. These results suggest that the right inferior frontal gyrus plays a role in the recovery of language function in the subacute stage of stroke-related aphasia by increasing the engagement of related brain areas. PMID:28250756

  19. Differential localization of pain-related neural responses during acupuncture stimulation using Blood Oxygen Level Dependent (BOLD) fMRI in a canine model.

    PubMed

    Chang, Suk-Ki; Jahng, Geon-Ho; Lee, Sung-Ho; Choi, Il-Whan; Choi, Chi-Bong; Choi, Woo-Suk

    2012-01-01

    The objective of this study was to differentiate the neuronal responses, which was related or unrelated, to pain associated with acupuncture stimulation, and to localize the brain regions with response to stimulation that is unrelated to pain by using Blood Oxygen Level Dependent (BOLD) functional MRI (fMRI). BOLD fMRI was performed in six normal healthy beagle dogs, during placebo and verum acupuncture stimulations, at the right side of BL60 (KunLun) acupoint before and after local anesthesia of the acupoint. The order of the four sessions was placebo; verum acupuncture stimulation; before local anesthesia; and followed by the same stimulation after local anesthesia. One-sample t-test analysis was performed to localize the activated or deactivated areas, during both pre-anesthesia and post-anesthesia. In order to compare the pre-anesthesia to post-anesthetic responses, and placebo to verum acupuncture stimulation, within-subject analysis was performed. The post-anesthetic verum acupuncture stimulation resulted in increased activations in the left somatic afferent area I and II, right visual and auditory association area, and the descending reticular activating system of the brainstem. In addition, differential areas during post-anesthesia compared to that of the pre-anesthesia were in the left olfactory peduncle and descending reticular activating system of the brainstem. These results indicate that the areas of specific neural pathway are considered to be unrelated to the pain response during acupuncture stimulation.

  20. Evidence of cortical reorganization of language networks after stroke with subacute Broca's aphasia: a blood oxygenation level dependent-functional magnetic resonance imaging study.

    PubMed

    Qiu, Wei-Hong; Wu, Hui-Xiang; Yang, Qing-Lu; Kang, Zhuang; Chen, Zhao-Cong; Li, Kui; Qiu, Guo-Rong; Xie, Chun-Qing; Wan, Gui-Fang; Chen, Shao-Qiong

    2017-01-01

    Aphasia is an acquired language disorder that is a common consequence of stroke. The pathogenesis of the disease is not fully understood, and as a result, current treatment options are not satisfactory. Here, we used blood oxygenation level-dependent functional magnetic resonance imaging to evaluate the activation of bilateral cortices in patients with Broca's aphasia 1 to 3 months after stroke. Our results showed that language expression was associated with multiple brain regions in which the right hemisphere participated in the generation of language. The activation areas in the left hemisphere of aphasia patients were significantly smaller compared with those in healthy adults. The activation frequency, volumes, and intensity in the regions related to language, such as the left inferior frontal gyrus (Broca's area), the left superior temporal gyrus, and the right inferior frontal gyrus (the mirror region of Broca's area), were lower in patients compared with healthy adults. In contrast, activation in the right superior temporal gyrus, the bilateral superior parietal lobule, and the left inferior temporal gyrus was stronger in patients compared with healthy controls. These results suggest that the right inferior frontal gyrus plays a role in the recovery of language function in the subacute stage of stroke-related aphasia by increasing the engagement of related brain areas.

  1. A particular effect of sleep, but not pain or depression, on the blood-oxygen-level dependent response during working memory tasks in patients with chronic pain.

    PubMed

    Elvemo, Nicolas A; Landrø, Nils I; Borchgrevink, Petter C; Håberg, Asta K

    2015-01-01

    Patients with chronic pain (CP) are often reported to have deficits in working memory. Pain impairs working memory, but so do depression and sleep problems, which are also common in CP. Depression has been linked to changes in brain activity in CP during working memory tasks, but the effect of sleep problems on working memory performance and brain activity remains to be investigated. Fifteen CP patients and 17 age-, sex-, and education-matched controls underwent blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging at 3T while performing block design 0-back, 2-back, and paced visual serial addition test paradigms. Subjects also reported their level of pain (Brief Pain Inventory), depression (Beck Depression Inventory II), and sleep problems (Pittsburgh Sleep Quality Index) and were tested outside the scanner with neuropsychological tests of working memory. The CP group reported significantly higher levels of pain, depression, and sleep problems. No significant performance difference was found on the neuropsychological tests in or outside the scanner between the two groups. There were no correlations between level of pain, depression, and sleep problems or between these and the neuropsychological test scores. CP patients exhibited significantly less brain activation and deactivation than controls in parietal and frontal lobes, which are the brain areas that normally show activation and deactivation during working memory tasks. Sleep problems independently and significantly modulated the BOLD response to the complex working memory tasks and were associated with decreased brain activation in task-positive regions and decreased deactivation in the default mode network in the CP group compared to the control group. The pain and depression scores covaried with working memory activation. Sleep problems in CP patients had a significant impact on the BOLD response during working memory tasks, independent of pain level and depression, even when

  2. Relationship between caffeine-induced changes in resting cerebral perfusion and blood oxygenation level-dependent signal.

    PubMed

    Laurienti, Paul J; Field, Aaron S; Burdette, Jonathan H; Maldjian, Joseph A; Yen, Yi-Fen; Moody, Dixon M

    2003-09-01

    Recent interest has emerged in the use of pharmacologic methods to maximize blood oxygenation level-dependent (BOLD) signal intensity changes in functional MR imaging (fMRI). Adenosine antagonists, such as caffeine and theophylline, have been identified as potential agents for this purpose. The present study was designed to determine whether caffeine-induced decreases in cerebral perfusion result in enhanced BOLD responses to visual and auditory stimuli. MR imaging was used to measure resting cerebral perfusion and stimulus-induced BOLD signal intensity changes in 19 patients. We evaluated the relationship between resting cerebral perfusion and the magnitude of BOLD signal intensity induced by visual and auditory stimulation under caffeine and placebo conditions. The data showed that changes in resting cerebral perfusion produced by caffeine are not a consistent predictor of BOLD signal intensity magnitude. Although all cerebral perfusion was reduced in all study participants in response to caffeine, only 47% of the participants experienced BOLD signal intensity increase. This finding was independent of the participants' usual caffeine consumption. The data presented herein show that the relationship between resting cerebral perfusion and the magnitude of BOLD signal intensity is complex. It is not possible to consistently enhance BOLD signal intensity magnitude by decreasing resting perfusion with caffeine. Future studies aimed at evaluating the relationship between perfusion and BOLD signal intensity changes should seek a means to selectively modulate known components of the neural and vascular responses independently.

  3. Oxygenation in cervical cancer and normal uterine cervix assessed using blood oxygenation level-dependent (BOLD) MRI at 3T.

    PubMed

    Hallac, Rami R; Ding, Yao; Yuan, Qing; McColl, Roderick W; Lea, Jayanthi; Sims, Robert D; Weatherall, Paul T; Mason, Ralph P

    2012-12-01

    Hypoxia is reported to be a biomarker for poor prognosis in cervical cancer. However, a practical noninvasive method is needed for the routine clinical evaluation of tumor hypoxia. This study examined the potential use of blood oxygenation level-dependent (BOLD) contrast MRI as a noninvasive technique to assess tumor vascular oxygenation at 3T. Following Institutional Review Board-approved informed consent and in compliance with the Health Insurance Portability and Accountability Act, successful results were achieved in nine patients with locally advanced cervical cancer [International Federation of Gynecology and Obstetrics (FIGO) stage IIA to IVA] and three normal volunteers. In the first four patients, dynamic T₂*-weighted MRI was performed in the transaxial plane using a multi-shot echo planar imaging sequence whilst patients breathed room air followed by oxygen (15 dm³/min). Later, a multi-echo gradient echo examination was added to provide quantitative R₂* measurements. The baseline T₂*-weighted signal intensity was quite stable, but increased to various extents in tumors on initiation of oxygen breathing. The signal in normal uterus increased significantly, whereas that in the iliacus muscle did not change. R₂* responded significantly in healthy uterus, cervix and eight cervical tumors. This preliminary study demonstrates that BOLD MRI of cervical cancer at 3T is feasible. However, more patients must be evaluated and followed clinically before any prognostic value can be determined. Copyright © 2012 John Wiley & Sons, Ltd.

  4. Artifact-reduced two-dimensional cine steady state free precession for myocardial blood- oxygen-level-dependent imaging.

    PubMed

    Zhou, Xiangzhi; Tsaftaris, Sotirios A; Liu, Ying; Tang, Richard; Klein, Rachel; Zuehlsdorff, Sven; Li, Debiao; Dharmakumar, Rohan

    2010-04-01

    To minimize image artifacts in long TR cardiac phase-resolved steady state free precession (SSFP) based blood-oxygen-level-dependent (BOLD) imaging. Nine healthy dogs (four male, five female, 20-25 kg) were studied in a clinical 1.5 Tesla MRI scanner to investigate the effect of temporal resolution, readout bandwidth, and motion compensation on long repetition time (TR) SSFP images. Breath-held 2D SSFP cine sequences with various temporal resolutions (10-204 ms), bandwidths (239-930 Hz/pixel), with and without first-order motion compensation were prescribed in the basal, mid-ventricular, and apical along the short axis. Preliminary myocardial BOLD studies in dogs with controllable coronary stenosis were performed to assess the benefits of artifact-reduction strategies. Shortening the readout time by means of increasing readout bandwidth had no observable reduction in image artifacts. However, increasing the temporal resolution in the presence of first-order motion compensation led to significant reduction in image artifacts. Preliminary studies demonstrated that BOLD signal changes can be reliably detected throughout the cardiac cycle. Artifact-reduction methods used in this study provide significant improvement in image quality compared with conventional long TR SSFP BOLD MRI. It is envisioned that the methods proposed here may enable reliable detection of myocardial oxygenation changes throughout the cardiac cycle with long TR SSFP-based myocardial BOLD MRI. (c) 2010 Wiley-Liss, Inc.

  5. Reproducing the Hemoglobin Saturation Profile, a Marker of the Blood Oxygenation Level Dependent (BOLD) fMRI Effect, at the Microscopic Level.

    PubMed

    Hadjistassou, Constantinos; Moyle, Keri; Ventikos, Yiannis

    2016-01-01

    The advent of functional MRI in the mid-1990s has catalyzed progress pertaining to scientific discoveries in neuroscience. With the prospect of elucidating the physiological aspect of the Blood Oxygenation Level Dependent (BOLD) effect we present a computational capillary-tissue system capable of mapping venous hemoglobin saturation- a marker of the BOLD hemodynamic response. Free and facilitated diffusion and convection for hemoglobin and oxygen are considered in the radial and axial directions. Hemoglobin reaction kinetics are governed by the oxyhemoglobin dissociation curve. Brain activation, mimicked by dynamic transitions in cerebral blood velocity (CBv) and oxidative metabolism (CMRO2), is simulated by normalized changes in m = (ΔCBv/CBv)/(ΔCMRO2/CMRO2) of values 2, 3 and 4. Venous hemoglobin saturation profiles and peak oxygenation results, for m = 2, based upon a 50% and a 25% increase in CBv and CMRO2, respectively, lie within physiological limits exhibiting excellent correlation with the BOLD signal, for short-duration stimuli. Our analysis suggests basal CBv and CMRO2 values of 0.6 mm/s and 200 μmol/100g/min. Coupled CBv and CMRO2 responses, for m = 3 and m = 4, overestimate peak hemoglobin saturation, confirming the system's responsiveness to changes in hematocrit, CBv and CMRO2. Finally, factoring in neurovascular effects, we show that no initial dip will be observed unless there is a time delay in the onset of increased CBv relative to CMRO2.

  6. Enhanced sensitivity with fast three-dimensional blood-oxygen-level-dependent functional MRI: comparison of SENSE-PRESTO and 2D-EPI at 3 T.

    PubMed

    Neggers, Sebastiaan F W; Hermans, Erno J; Ramsey, Nick F

    2008-08-01

    A major impetus in functional MRI development is to enhance sensitivity to changes in neural activity. One way to improve sensitivity is to enhance contrast to noise ratio, for instance by increasing field strength or the number of receiving coils. If these parameters are fixed, there is still the possibility to optimize scans by altering speed or signal strength [signal-to-noise ratio (SNR)]. We here demonstrate a very fast whole-brain scan, by combining a three-dimensional (3D)-PRESTO (principle of echo shifting with a train of observations) pulse sequence with a commercial eight-channel head coil and sensitivity encoding (SENSE). 3D-PRESTO uses time optimally by means of echo shifting. Moreover, 3D scans can accommodate SENSE in two directions, reducing scan time proportionally. The present PRESTO-SENSE sequence achieves full brain coverage within 500 ms. We compared this with a two-dimensional (2D) echo planar imaging (EPI) scan with identical brain coverage on 10 volunteers. Resting-state temporal SNR in the blood-oxygen-level-dependent (BOLD) frequency range and T-statistics for thumb movement and visual checkerboard activations were compared. Results show improved temporal SNR across the brain for PRESTO-SENSE compared with EPI. The percentage signal change and relative standard deviation of the noise were smaller for PRESTO-SENSE. Sensitivity for brain activation, as reflected by T-values, was consistently higher for PRESTO, and this seemed to be mainly due to the increased number of observations within a fixed time period. We conclude that PRESTO accelerated with SENSE in two directions can be more sensitive to BOLD signal changes than the widely used 2D-EPI, when a fixed amount of time is available for functional MRI scanning. Copyright (c) 2008 John Wiley & Sons, Ltd.

  7. Synthetic Generation of Myocardial Blood-Oxygen-Level-Dependent MRI Time Series via Structural Sparse Decomposition Modeling

    PubMed Central

    Rusu, Cristian; Morisi, Rita; Boschetto, Davide; Dharmakumar, Rohan; Tsaftaris, Sotirios A.

    2014-01-01

    This paper aims to identify approaches that generate appropriate synthetic data (computer generated) for Cardiac Phase-resolved Blood-Oxygen-Level-Dependent (CP–BOLD) MRI. CP–BOLD MRI is a new contrast agent- and stress-free approach for examining changes in myocardial oxygenation in response to coronary artery disease. However, since signal intensity changes are subtle, rapid visualization is not possible with the naked eye. Quantifying and visualizing the extent of disease relies on myocardial segmentation and registration to isolate the myocardium and establish temporal correspondences and ischemia detection algorithms to identify temporal differences in BOLD signal intensity patterns. If transmurality of the defect is of interest pixel-level analysis is necessary and thus a higher precision in registration is required. Such precision is currently not available affecting the design and performance of the ischemia detection algorithms. In this work, to enable algorithmic developments of ischemia detection irrespective to registration accuracy, we propose an approach that generates synthetic pixel-level myocardial time series. We do this by (a) modeling the temporal changes in BOLD signal intensity based on sparse multi-component dictionary learning, whereby segmentally derived myocardial time series are extracted from canine experimental data to learn the model; and (b) demonstrating the resemblance between real and synthetic time series for validation purposes. We envision that the proposed approach has the capacity to accelerate development of tools for ischemia detection while markedly reducing experimental costs so that cardiac BOLD MRI can be rapidly translated into the clinical arena for the noninvasive assessment of ischemic heart disease. PMID:24691119

  8. Synthetic generation of myocardial blood-oxygen-level-dependent MRI time series via structural sparse decomposition modeling.

    PubMed

    Rusu, Cristian; Morisi, Rita; Boschetto, Davide; Dharmakumar, Rohan; Tsaftaris, Sotirios A

    2014-07-01

    This paper aims to identify approaches that generate appropriate synthetic data (computer generated) for cardiac phase-resolved blood-oxygen-level-dependent (CP-BOLD) MRI. CP-BOLD MRI is a new contrast agent- and stress-free approach for examining changes in myocardial oxygenation in response to coronary artery disease. However, since signal intensity changes are subtle, rapid visualization is not possible with the naked eye. Quantifying and visualizing the extent of disease relies on myocardial segmentation and registration to isolate the myocardium and establish temporal correspondences and ischemia detection algorithms to identify temporal differences in BOLD signal intensity patterns. If transmurality of the defect is of interest pixel-level analysis is necessary and thus a higher precision in registration is required. Such precision is currently not available affecting the design and performance of the ischemia detection algorithms. In this work, to enable algorithmic developments of ischemia detection irrespective to registration accuracy, we propose an approach that generates synthetic pixel-level myocardial time series. We do this by 1) modeling the temporal changes in BOLD signal intensity based on sparse multi-component dictionary learning, whereby segmentally derived myocardial time series are extracted from canine experimental data to learn the model; and 2) demonstrating the resemblance between real and synthetic time series for validation purposes. We envision that the proposed approach has the capacity to accelerate development of tools for ischemia detection while markedly reducing experimental costs so that cardiac BOLD MRI can be rapidly translated into the clinical arena for the noninvasive assessment of ischemic heart disease.

  9. How bold is blood oxygenation level-dependent (BOLD) magnetic resonance imaging of the kidney? Opportunities, challenges and future directions.

    PubMed

    Niendorf, T; Pohlmann, A; Arakelyan, K; Flemming, B; Cantow, K; Hentschel, J; Grosenick, D; Ladwig, M; Reimann, H; Klix, S; Waiczies, S; Seeliger, E

    2015-01-01

    Renal tissue hypoperfusion and hypoxia are key elements in the pathophysiology of acute kidney injury and its progression to chronic kidney disease. Yet, in vivo assessment of renal haemodynamics and tissue oxygenation remains a challenge. Many of the established approaches are invasive, hence not applicable in humans. Blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) offers an alternative. BOLD-MRI is non-invasive and indicative of renal tissue oxygenation. Nonetheless, recent (pre-) clinical studies revived the question as to how bold renal BOLD-MRI really is. This review aimed to deliver some answers. It is designed to inspire the renal physiology, nephrology and imaging communities to foster explorations into the assessment of renal oxygenation and haemodynamics by exploiting the powers of MRI. For this purpose, the specifics of renal oxygenation and perfusion are outlined. The fundamentals of BOLD-MRI are summarized. The link between tissue oxygenation and the oxygenation-sensitive MR biomarker T2∗ is outlined. The merits and limitations of renal BOLD-MRI in animal and human studies are surveyed together with their clinical implications. Explorations into detailing the relation between renal T2∗ and renal tissue partial pressure of oxygen (pO2 ) are discussed with a focus on factors confounding the T2∗ vs. tissue pO2 relation. Multi-modality in vivo approaches suitable for detailing the role of the confounding factors that govern T2∗ are considered. A schematic approach describing the link between renal perfusion, oxygenation, tissue compartments and renal T2∗ is proposed. Future directions of MRI assessment of renal oxygenation and perfusion are explored.

  10. Renal Blood Oxygenation Level-dependent Imaging in Longitudinal Follow-up of Donated and Remaining Kidneys.

    PubMed

    Seif, Maryam; Eisenberger, Ute; Binser, Tobias; Thoeny, Harriet C; Krauer, Fabienne; Rusch, Aurelia; Boesch, Chris; Vogt, Bruno; Vermathen, Peter

    2016-06-01

    Purpose To determine renal oxygenation changes associated with uninephrectomy and transplantation in both native donor kidneys and transplanted kidneys by using blood oxygenation level-dependent (BOLD) MR imaging. Materials and Methods The study protocol was approved by the local ethics committee. Thirteen healthy kidney donors and their corresponding recipients underwent kidney BOLD MR imaging with a 3-T imager. Written informed consent was obtained from each subject. BOLD MR imaging was performed in donors before uninephrectomy and in donors and recipients 8 days, 3 months, and 12 months after transplantation. R2* values, which are inversely related to tissue partial pressure of oxygen, were determined in the cortex and medulla. Longitudinal R2* changes were statistically analyzed by using repeated measures one-way analysis of variance with post hoc pair-wise comparisons. Results R2* values in the remaining kidneys significantly decreased early after uninephrectomy in both the medulla and cortex (P < .003), from 28.9 sec(-1) ± 2.3 to 26.4 sec(-1) ± 2.5 in the medulla and from 18.3 sec(-1) ± 1.5 to 16.3 sec(-1) ± 1.0 in the cortex, indicating increased oxygen content. In donors, R2* remained significantly decreased in both the medulla and cortex at 3 (P < .01) and 12 (P < .01) months. In transplanted kidneys, R2* remained stable during the first year after transplantation, with no significant change. Among donors, cortical R2* was found to be negatively correlated with estimated glomerular filtration rate (R = -0.47, P < .001). Conclusion The results suggest that BOLD MR imaging may potentially be used to monitor renal functional changes in both remaining and corresponding transplanted kidneys. (©) RSNA, 2016.

  11. Acute alcohol intoxication impairs top-down regulation of Stroop incongruity as revealed by blood oxygen level-dependent functional magnetic resonance imaging.

    PubMed

    Marinkovic, Ksenija; Rickenbacher, Elizabeth; Azma, Sheeva; Artsy, Elinor

    2012-02-01

    Functional neuroanatomy of executive functions has been delineated in a large number of neuroimaging studies using conflict-inducing tasks. The neural basis of alcohol's effects on cognitive control is poorly understood despite the evidence of impaired ability to evaluate competing demands and to inhibit maladaptive responses. To investigate the effects of moderate intoxication, healthy social drinkers participated in both alcohol (0.60 g/kg ethanol for men, 0.55 g/kg for women) and placebo conditions while being scanned using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI). A modified four-color Stroop task combined reading and color naming and used manual responses. Twenty subjects (10 women) were instructed to press a button corresponding to the font color except when a word was written in gray in which case they had to respond to the meaning of the word. Alcohol increased reaction times and a tendency to make more errors on incongruent trials. Behavioral indices of alcohol-induced premature responding correlated with the current drinking levels and impulsivity traits, suggesting an interaction between alcohol effects and personality predispositions. A distributed frontoparietal cortical network was activated by incongruity. However, moderate alcohol inebriation selectively attenuated anterior cingulate cortex (ACC) activation during both high-conflict trials and erroneous responses, indicating vulnerability of the regulative function subserved by the ACC. By disrupting top-down, strategic processing, alcohol may interfere with goal-directed behavior, resulting in poor self control. The present results support models proposing that alcohol-induced prefrontal impairments diminish inhibitory control and are modulated by dispositional risk factors and levels of alcohol consumption.

  12. Parametric dependence of myocardial blood oxygen level dependent, balanced steady-state free-precession imaging at 1.5 T: theory and experiments.

    PubMed

    Zhou, Xiangzhi; Tang, Richard; Klein, Rachel; Li, Debiao; Dharmakumar, Rohan

    2010-02-01

    Myocardial blood oxygen level dependent, balanced steady-state free precession (bSSFP) imaging is a relatively new technique for evaluating myocardial oxygenation changes in the presence of coronary artery stenosis. However, the dependence of myocardial bSSFP blood oxygen level dependent signal on imaging parameters has not been well studied. In this work, modeling capillaries as cylinders that act as magnetic perturbers, the Monte Carlo method was used to simulate spin relaxation via diffusion in a field variation inside and outside blood vessels. bSSFP signal changes at various levels of capillary blood oxygen saturation, for a range of pulse repetition times, flip angle, capillary blood volume fraction, vessel wall permeability, water diffusion coefficient, vessel angle to static magnetic field, and the impact of bulk frequency shifts were studied. The theoretical dependence of bSSFP blood oxygen level dependent contrast on pulse repetition times and flip angle was confirmed by experiments in an animal model with controllable coronary stenosis. Results showed that, with the standard bSSFP acquisition, optimum bSSFP blood oxygen level dependent contrast could be obtained at pulse repetition times = 6.0 ms and flip angle = 70 degrees . Additional technical improvements that preserve the image quality may be necessary to further increase the myocardial bSSFP blood oxygen level dependent sensitivity at 1.5 T through even longer pulse repetition times.

  13. Fractal Analysis of Brain Blood Oxygenation Level Dependent (BOLD) Signals from Children with Mild Traumatic Brain Injury (mTBI)

    PubMed Central

    Dona, Olga; DeMatteo, Carol; Connolly, John F.

    2017-01-01

    Background Conventional imaging techniques are unable to detect abnormalities in the brain following mild traumatic brain injury (mTBI). Yet patients with mTBI typically show delayed response on neuropsychological evaluation. Because fractal geometry represents complexity, we explored its utility in measuring temporal fluctuations of brain resting state blood oxygen level dependent (rs-BOLD) signal. We hypothesized that there could be a detectable difference in rs-BOLD signal complexity between healthy subjects and mTBI patients based on previous studies that associated reduction in signal complexity with disease. Methods Fifteen subjects (13.4 ± 2.3 y/o) and 56 age-matched (13.5 ± 2.34 y/o) healthy controls were scanned using a GE Discovery MR750 3T MRI and 32-channel RF-coil. Axial FSPGR-3D images were used to prescribe rs-BOLD (TE/TR = 35/2000ms), acquired over 6 minutes. Motion correction was performed and anatomical and functional images were aligned and spatially warped to the N27 standard atlas. Fractal analysis, performed on grey matter, was done by estimating the Hurst exponent using de-trended fluctuation analysis and signal summation conversion methods. Results and Conclusions Voxel-wise fractal dimension (FD) was calculated for every subject in the control group to generate mean and standard deviation maps for regional Z-score analysis. Voxel-wise validation of FD normality across controls was confirmed, and non-Gaussian voxels (3.05% over the brain) were eliminated from subsequent analysis. For each mTBI patient, regions where Z-score values were at least 2 standard deviations away from the mean (i.e. where |Z| > 2.0) were identified. In individual patients the frequently affected regions were amygdala (p = 0.02), vermis(p = 0.03), caudate head (p = 0.04), hippocampus(p = 0.03), and hypothalamus(p = 0.04), all previously reported as dysfunctional after mTBI, but based on group analysis. It is well known that the brain is best modeled as a complex

  14. Fractal Analysis of Brain Blood Oxygenation Level Dependent (BOLD) Signals from Children with Mild Traumatic Brain Injury (mTBI).

    PubMed

    Dona, Olga; Noseworthy, Michael D; DeMatteo, Carol; Connolly, John F

    2017-01-01

    Conventional imaging techniques are unable to detect abnormalities in the brain following mild traumatic brain injury (mTBI). Yet patients with mTBI typically show delayed response on neuropsychological evaluation. Because fractal geometry represents complexity, we explored its utility in measuring temporal fluctuations of brain resting state blood oxygen level dependent (rs-BOLD) signal. We hypothesized that there could be a detectable difference in rs-BOLD signal complexity between healthy subjects and mTBI patients based on previous studies that associated reduction in signal complexity with disease. Fifteen subjects (13.4 ± 2.3 y/o) and 56 age-matched (13.5 ± 2.34 y/o) healthy controls were scanned using a GE Discovery MR750 3T MRI and 32-channel RF-coil. Axial FSPGR-3D images were used to prescribe rs-BOLD (TE/TR = 35/2000ms), acquired over 6 minutes. Motion correction was performed and anatomical and functional images were aligned and spatially warped to the N27 standard atlas. Fractal analysis, performed on grey matter, was done by estimating the Hurst exponent using de-trended fluctuation analysis and signal summation conversion methods. Voxel-wise fractal dimension (FD) was calculated for every subject in the control group to generate mean and standard deviation maps for regional Z-score analysis. Voxel-wise validation of FD normality across controls was confirmed, and non-Gaussian voxels (3.05% over the brain) were eliminated from subsequent analysis. For each mTBI patient, regions where Z-score values were at least 2 standard deviations away from the mean (i.e. where |Z| > 2.0) were identified. In individual patients the frequently affected regions were amygdala (p = 0.02), vermis(p = 0.03), caudate head (p = 0.04), hippocampus(p = 0.03), and hypothalamus(p = 0.04), all previously reported as dysfunctional after mTBI, but based on group analysis. It is well known that the brain is best modeled as a complex system. Therefore a measure of complexity

  15. Generating level-dependent models of cervical and thoracic spinal cord injury: Exploring the interplay of neuroanatomy, physiology, and function.

    PubMed

    Wilcox, Jared T; Satkunendrarajah, Kajana; Nasirzadeh, Yasmin; Laliberte, Alex M; Lip, Alyssa; Cadotte, David W; Foltz, Warren D; Fehlings, Michael G

    2017-09-01

    performance and neuron counts. Level-dependent models were generated using clip-compression SCI, with marked and reliable differences in forelimb performance and specific neuron pool loss. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Rapid structural alterations of the active zone lead to sustained changes in neurotransmitter release.

    PubMed

    Matz, Jacob; Gilyan, Andrew; Kolar, Annette; McCarvill, Terrence; Krueger, Stefan R

    2010-05-11

    The likelihood with which an action potential elicits neurotransmitter release, the release probability (p(r)), is an important component of synaptic strength. Regulatory mechanisms controlling several steps of synaptic vesicle (SV) exocytosis may affect p(r), yet their relative importance in determining p(r) and eliciting temporal changes in neurotransmitter release at individual synapses is largely unknown. We have investigated whether the size of the active zone cytomatrix is a major determinant of p(r) and whether changes in its size lead to corresponding alterations in neurotransmitter release. We have used a fluorescent sensor of SV exocytosis, synaptophysin-pHluorin, to measure p(r) at individual synapses with high accuracy and employed a fluorescently labeled cytomatrix protein, Bassoon, to quantify the amount of active zone cytomatrix present at these synapses. We find that, for synapses made by a visually identified presynaptic neuron, p(r) is indeed strongly correlated with the amount of active zone cytomatrix present at the presynaptic specialization. Intriguingly, active zone cytomatrices are frequently subject to synapse-specific changes in size on a time scale of minutes. These spontaneous alterations in active zone size are associated with corresponding changes in neurotransmitter release. Our results suggest that the size of the active zone cytomatrix has a large influence on the reliability of synaptic transmission. Furthermore, they implicate mechanisms leading to rapid structural alterations at active zones in synapse-specific forms of plasticity.

  17. Choice from non-choice: predicting consumer preferences from blood oxygenation level-dependent signals obtained during passive viewing.

    PubMed

    Levy, Ifat; Lazzaro, Stephanie C; Rutledge, Robb B; Glimcher, Paul W

    2011-01-05

    Decision-making is often viewed as a two-stage process, where subjective values are first assigned to each option and then the option of the highest value is selected. Converging evidence suggests that these subjective values are represented in the striatum and medial prefrontal cortex (MPFC). A separate line of evidence suggests that activation in the same areas represents the values of rewards even when choice is not required, as in classical conditioning tasks. However, it is unclear whether the same neural mechanism is engaged in both cases. To address this question we measured brain activation with functional magnetic resonance imaging while human subjects passively viewed individual consumer goods. We then sampled activation from predefined regions of interest and used it to predict subsequent choices between the same items made outside of the scanner. Our results show that activation in the striatum and MPFC in the absence of choice predicts subsequent choices, suggesting that these brain areas represent value in a similar manner whether or not choice is required.

  18. Stimulus-induced dissociation of neuronal firing rates and local field potential gamma power and its relationship to the blood oxygen level-dependent signal in macaque primary visual cortex

    PubMed Central

    Bartolo, M J; Gieselmann, M A; Vuksanovic, V; Hunter, D; Sun, L; Chen, X; Delicato, L S; Thiele, A

    2011-01-01

    The functional magnetic resonance imaging (fMRI) blood oxygenation level-dependent (BOLD) signal is regularly used to assign neuronal activity to cognitive function. Recent analyses have shown that the local field potential (LFP) gamma power is a better predictor of the fMRI BOLD signal than spiking activity. However, LFP gamma power and spiking activity are usually correlated, clouding the analysis of the neural basis of the BOLD signal. We show that changes in LFP gamma power and spiking activity in the primary visual cortex (V1) of the awake primate can be dissociated by using grating and plaid pattern stimuli, which differentially engage surround suppression and cross-orientation inhibition/facilitation within and between cortical columns. Grating presentation yielded substantial V1 LFP gamma frequency oscillations and significant multi-unit activity. Plaid pattern presentation significantly reduced the LFP gamma power while increasing population multi-unit activity. The fMRI BOLD activity followed the LFP gamma power changes, not the multi-unit activity. Inference of neuronal activity from the fMRI BOLD signal thus requires detailed a priori knowledge of how different stimuli or tasks activate the cortical network. PMID:22081989

  19. Photoreactivity of the occipital cortex measured by functional magnetic resonance imaging-blood oxygenation level dependent in migraine patients and healthy volunteers: pathophysiological implications.

    PubMed

    Martín, Helena; Sánchez del Río, Margarita; de Silanes, Carlos López; Álvarez-Linera, Juan; Hernández, Juan Antonio; Pareja, Juan A

    2011-01-01

    The brain of migraineurs is hyperexcitable, particularly the occipital cortex, which is probably hypersensitive to light. Photophobia or hypersensitivity to light may be accounted for by an increased excitability of trigeminal, the visual pathways, and the occipital cortex. To study light sensitivity and photophobia by assessing the response to light stimuli with functional magnetic resonance imaging-blood oxygenation level dependent (fMRI-BOLD) of the occipital cortex in migraineurs and in controls. Also, to try to decipher the contribution of the occipital cortex to photophobia and whether the cortical reactivity of migraineurs may be part of a constitutional (defensive) mechanism or represents an acquired (sensitization) phenomenon. Nineteen patients with migraine (7 with aura and 12 without aura) and 19 controls were studied with fMRI-BOLD during 4 increasing light intensities. Eight axial image sections of 0.5 cm that covered the occipital cortex were acquired for each intensity. We measured the extension and the intensity of activation for every light stimuli. Photophobia was estimated according to a 0 to 3 semiquantitative scale of light discomfort. Migraineurs had a significantly higher number of fMRI-activated voxels at low (320.4 for migraineurs [SD = 253.9] and 164.3 for controls [SD = 102.7], P = .027) and medium-low luminance levels (501.2 for migraineurs [SD = 279.5] and 331.1 for controls [SD = 194.3], P = .034) but not at medium-high (579.5 for migraineurs [SD = 201.4] and 510.2 for controls [SD = 239.5], P = .410) and high light stimuli (496.2 for migraineurs [SD = 216.2] and 394.7 for controls [SD = 240], P = .210). No differences were found with respect to the voxel activation intensity (amplitude of the BOLD wave) between migraineurs and controls (8.98 [SD = 2.58] vs 7.99 [SD = 2.57], P = .25; 10.82 [SD = 3.27] vs 9.81 [SD = 3.19], P = .31; 11.90 [SD = 3.18] vs 11.06 [SD = 2.56], P = .62; 11.45 [SD = 2.65] vs 10.25 [SD = 2.22], P = .16). Light

  20. Variability in blood oxygen level dependent (BOLD) signal in patients with stroke-induced and primary progressive aphasia.

    PubMed

    Bonakdarpour, B; Beeson, P M; DeMarco, A T; Rapcsak, S Z

    2015-01-01

    Although fMRI is increasingly used to assess language-related brain activation in patients with aphasia, few studies have examined the hemodynamic response function (HRF) in perilesional, and contralesional areas of the brain. In addition, the relationship between HRF abnormalities and other variables such as lesion size and severity of aphasia has not been explored. The objective of this study was to investigate changes in HRF signal during language-related neural activation in patients with stroke-induced aphasia (SA). We also examined the status of the HRF in patients with aphasia due to nonvascular etiology, namely, primary progressive aphasia (PPA). Five right handed SA patients, three PPA patients, and five healthy individuals participated in the study. Structural damage was quantified with T1-weighted MR images. Functional MR imaging was performed with long trial event-related design and an overt naming task to measure BOLD signal time to peak (TTP) and percent signal change (ΔS). In SA patients, the average HRF TTP was significantly delayed in the left hemisphere regions involved in naming compared to healthy participants and PPA patients. However, ΔS was not different in SA patients compared to the other two groups. Delay in HRF TTP in the left hemisphere naming network of SA patients was correlated with lesion size and showed a negative correlation with global language function. There were no significant differences in the HRF TTP and ΔS in the right hemisphere homologues of the naming network or in the left and the right occipital control regions across the three groups. In PPA patients, HRF had a normal pattern. Our results indicate that abnormal task-related HRF is primarily found in the left hemisphere language network of SA patients and raise the possibility that abnormal physiology superimposed on structural damage may contribute to the clinical deficit. Follow-up investigations in a larger sample of age-matched healthy individuals, SA, and PPA

  1. Differential effects of aging, drinking and exercise on serum cholesterol levels dependent on the PPARA-V227A polymorphism.

    PubMed

    Naito, Hisao; Kamijima, Michihiro; Yamanoshita, Osamu; Nakahara, Ai; Katoh, Takahiko; Tanaka, Naoki; Aoyama, Toshifumi; Gonzalez, Frank J; Nakajima, Tamie

    2007-09-01

    Peroxisome proliferator-activated receptor alpha (PPARA alpha) plays a pivotal role in lipid metabolism. Our previous study reported that PPARA-V227A was a major polymorphism in Japanese, which was associated with markedly lower serum total cholesterol (TC) levels, which were significantly affected by alcohol drinking compared to subjects with the wild-type (PPARA-WT) allele. However, serum lipids are also associated with aging and exercise frequency. The objective of the present study was to evaluate the relationship between PPARA-V227A and these factors. Genetic analysis of the polymorphism was performed in 1058 Japanese men and 281 women, and the relationship with aging, drinking and exercise on serum lipids was analyzed in 989 men and 245 women after exclusion criteria had been applied. In men, drinking increased high-density lipoprotein cholesterol (HDL-C) levels in both PPARA-WT and A227 carriers, but to a significantly higher degree in the latter. In women, TC and low-density lipoprotein cholesterol (LDL-C) levels in the A227 carriers drinking at least once a week were significantly higher than in PPARA-WT carriers. TC and LDL-C levels in males with PPARA-WT increased with aging regardless of drinking habit, while LDL-C levels in the A227 drinking carriers were significantly lower in 45-yr-old or older subjects than in 35- to 45-yr-olds. In addition, no effect of exercising was observed in the A227 carriers, while increase in the HDL-C of the PPARA-WT carriers was exercise frequency dependent. These results suggest that the influence of drinking, aging or exercise on TC, LDL-C and HDL-C levels in the A227 carriers may be different from those in the PPARA-WT subjects.

  2. Synapse-Specific Control of Experience-Dependent Plasticity by Presynaptic NMDA Receptors

    PubMed Central

    Larsen, Rylan S.; Smith, Ikuko T.; Miriyala, Jayalakshmi; Han, Ji Eun; Corlew, Rebekah J.; Smith, Spencer L.; Philpot, Benjamin D.

    2014-01-01

    SUMMARY Sensory experience orchestrates the development of cortical circuitry by adaptively modifying neuro-transmission and synaptic connectivity. However, the mechanisms underlying these experience-dependent modifications remain elusive. Here we demonstrate that visual experience suppresses a presynaptic NMDA receptor (preNMDAR)-mediated form of timing-dependent long-term depression (tLTD) at visual cortex layer (L) 4-2/3 synapses. This tLTD can be maintained during development, or reinstated in adulthood, by sensory deprivation. The changes in tLTD are mirrored by changes in glutamate release; visual deprivation enhances both tLTD and glutamate release. These effects require the GluN3A NMDAR subunit, the levels of which are increased by visual deprivation. Further, by coupling the pathway-specific optogenetic induction of tLTD with cell-type-specific NMDAR deletion, we find that visual experience modifies preNMDAR-mediated plasticity specifically at L4-L2/3 synapses. PMID:25144876

  3. Cadherin-9 Regulates Synapse-Specific Differentiation in the Developing Hippocampus

    PubMed Central

    Williams, Megan E.; Wilke, Scott A.; Daggett, Anthony; Davis, Elizabeth; Otto, Stefanie; Ravi, Deepak; Ripley, Beth; Bushong, Eric A.; Ellisman, Mark H.; Klein, Gerd; Ghosh, Anirvan

    2012-01-01

    SUMMARY Our understanding of mechanisms that regulate the differentiation of specific classes of synapses is limited. Here, we investigate the formation of synapses between hippocampal dentate gyrus (DG) neurons and their target CA3 neurons and find that DG neurons preferentially form synapses with CA3 rather than DG or CA1 neurons in culture, suggesting that specific interactions between DG and CA3 neurons drive synapse formation. Cadherin-9 is expressed selectively in DG and CA3 neurons, and downregulation of cadherin-9 in CA3 neurons leads to a selective decrease in the number and size of DG synapses onto CA3 neurons. In addition, loss of cadherin-9 from DG or CA3 neurons in vivo leads to striking defects in the formation and differentiation of the DG-CA3 mossy fiber synapse. These observations indicate that cadherin-9 bidirectionally regulates DG-CA3 synapse development and highlight the critical role of differentially expressed molecular cues in establishing specific connections in the mammalian brain. PMID:21867881

  4. Synapse Specificity of Long-Term Potentiation Breaks Down with Aging

    ERIC Educational Resources Information Center

    Ris, Laurence; Godaux, Emile

    2007-01-01

    Memory shows age-related decline. According to the current prevailing theoretical model, encoding of memories relies on modifications in the strength of the synapses connecting the different cells within a neuronal network. The selective increases in synaptic weight are thought to be biologically implemented by long-term potentiation (LTP). Here,…

  5. Synapse Specificity of Long-Term Potentiation Breaks Down with Aging

    ERIC Educational Resources Information Center

    Ris, Laurence; Godaux, Emile

    2007-01-01

    Memory shows age-related decline. According to the current prevailing theoretical model, encoding of memories relies on modifications in the strength of the synapses connecting the different cells within a neuronal network. The selective increases in synaptic weight are thought to be biologically implemented by long-term potentiation (LTP). Here,…

  6. Angioplasty and stenting for severe vertebral artery orifice stenosis: effects on cerebellar function remodeling verified by blood oxygen level-dependent functional magnetic resonance imaging

    PubMed Central

    Liu, Bo; Li, Zhiwei; Xie, Peng

    2014-01-01

    Vertebral artery orifice stenting may improve blood supply of the posterior circulation of the brain to regions such as the cerebellum and brainstem. However, previous studies have mainly focused on recovery of cerebral blood flow and perfusion in the posterior circulation after interventional therapy. This study examined the effects of functional recovery of local brain tissue on cerebellar function remodeling using blood oxygen level-dependent functional magnetic resonance imaging before and after interventional therapy. A total of 40 Chinese patients with severe unilateral vertebral artery orifice stenosis were enrolled in this study. Patients were equally and randomly assigned to intervention and control groups. The control group received drug treatment only. The intervention group received vertebral artery orifice angioplasty and stenting + identical drug treatment to the control group. At 13 days after treatment, the Dizziness Handicap Inventory score was compared between the intervention and control groups. Cerebellar function remodeling was observed between the two groups using blood oxygen level-dependent functional magnetic resonance imaging. The improvement in dizziness handicap and cerebellar function was more obvious in the intervention group than in the control group. Interventional therapy for severe vertebral artery orifice stenosis may effectively promote cerebellar function remodeling and exert neuroprotective effects. PMID:25657727

  7. Measuring vascular reactivity with resting-state blood oxygenation level-dependent (BOLD) signal fluctuations: A potential alternative to the breath-holding challenge?

    PubMed

    Jahanian, Hesamoddin; Christen, Thomas; Moseley, Michael E; Pajewski, Nicholas M; Wright, Clinton B; Tamura, Manjula K; Zaharchuk, Greg

    2016-01-01

    Measurement of the ability of blood vessels to dilate and constrict, known as vascular reactivity, is often performed with breath-holding tasks that transiently raise arterial blood carbon dioxide (PaCO2) levels. However, following the proper commands for a breath-holding experiment may be difficult or impossible for many patients. In this study, we evaluated two approaches for obtaining vascular reactivity information using blood oxygenation level-dependent signal fluctuations obtained from resting-state functional magnetic resonance imaging data: physiological fluctuation regression and coefficient of variation of the resting-state functional magnetic resonance imaging signal. We studied a cohort of 28 older adults (69 ± 7 years) and found that six of them (21%) could not perform the breath-holding protocol, based on an objective comparison with an idealized respiratory waveform. In the subjects that could comply, we found a strong linear correlation between data extracted from spontaneous resting-state functional magnetic resonance imaging signal fluctuations and the blood oxygenation level-dependent percentage signal change during breath-holding challenge ( R(2 )= 0.57 and 0.61 for resting-state physiological fluctuation regression and resting-state coefficient of variation methods, respectively). This technique may eliminate the need for subject cooperation, thus allowing the evaluation of vascular reactivity in a wider range of clinical and research conditions in which it may otherwise be impractical.

  8. A review of calibrated blood oxygenation level-dependent (BOLD) methods for the measurement of task-induced changes in brain oxygen metabolism.

    PubMed

    Blockley, Nicholas P; Griffeth, Valerie E M; Simon, Aaron B; Buxton, Richard B

    2013-08-01

    The dynamics of the blood oxygenation level-dependent (BOLD) response are dependent on changes in cerebral blood flow, cerebral blood volume and the cerebral metabolic rate of oxygen consumption. Furthermore, the amplitude of the response is dependent on the baseline physiological state, defined by the haematocrit, oxygen extraction fraction and cerebral blood volume. As a result of this complex dependence, the accurate interpretation of BOLD data and robust intersubject comparisons when the baseline physiology is varied are difficult. The calibrated BOLD technique was developed to address these issues. However, the methodology is complex and its full promise has not yet been realised. In this review, the theoretical underpinnings of calibrated BOLD, and issues regarding this theory that are still to be resolved, are discussed. Important aspects of practical implementation are reviewed and reported applications of this methodology are presented. Copyright © 2012 John Wiley & Sons, Ltd.

  9. Assessing the end-organ in peripheral arterial occlusive disease—from contrast—enhanced ultrasound to blood-oxygen-level-dependent MR imaging

    PubMed Central

    Partovi, Sasan; Jacobi, Bjoern; Fergus, Nathan; Schulte, Anja-Carina; Robbin, Mark R.; Bilecen, Deniz; Staub, Daniel

    2014-01-01

    Peripheral arterial occlusive disease (PAOD) is a result of atherosclerotic disease which is currently the leading cause of morbidity and mortality in the western world. Patients with PAOD may present with intermittent claudication or symptoms related to critical limb ischemia. PAOD is associated with increased mortality rates. Stenoses and occlusions are usually detected by macrovascular imaging, including ultrasound and cross-sectional methods. From a pathophysiological view these stenoses and occlusions are affecting the microperfusion in the functional end-organs, such as the skin and skeletal muscle. In the clinical arena new imaging technologies enable the evaluation of the microvasculature. Two technologies currently under investigation for this purpose on the end-organ level in PAOD patients are contrast-enhanced ultrasound (CEUS) and blood-oxygen-level-dependent (BOLD) MR imaging (MRI). The following article is providing an overview about these evolving techniques with a specific focus on skeletal muscle microvasculature imaging in PAOD patients. PMID:24834413

  10. Low-frequency oscillations measured in the periphery with near-infrared spectroscopy are strongly correlated with blood oxygen level-dependent functional magnetic resonance imaging signals

    NASA Astrophysics Data System (ADS)

    Tong, Yunjie; Hocke, Lia Maria; Licata, Stephanie C.; deB. Frederick, Blaise

    2012-10-01

    Low-frequency oscillations (LFOs) in the range of 0.01-0.15 Hz are commonly observed in functional imaging studies, such as blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) and functional near-infrared spectroscopy (fNIRS). Some of these LFOs are nonneuronal and are closely related to autonomic physiological processes. In the current study, we conducted a concurrent resting-state fMRI and NIRS experiment with healthy volunteers. LFO data was collected simultaneously at peripheral sites (middle fingertip and big toes) by NIRS, and centrally in the brain by BOLD fMRI. The cross-correlations of the LFOs collected from the finger, toes, and brain were calculated. Our data show that the LFOs measured in the periphery (NIRS signals) and in the brain (BOLD fMRI) were strongly correlated with varying time delays. This demonstrates that some portion of the LFOs actually reflect systemic physiological circulatory effects. Furthermore, we demonstrated that NIRS is effective for measuring the peripheral LFOs, and that these LFOs and the temporal shifts between them are consistent in healthy participants and may serve as useful biomarkers for detecting and monitoring circulatory dysfunction.

  11. Blood Oxygenation Level-dependent Magnetic Resonance Imaging of Breast Cancer: Correlation with Carbonic Anhydrase IX and Vascular Endothelial Growth Factor

    PubMed Central

    Wang, Ying; Liu, Min; Jin, Mu-Lan

    2017-01-01

    Background: Blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is a functional MRI technique which involves using the paramagnetic properties of deoxyhemoglobin to image the local tissue oxygen concentration. The purpose of this study was to investigate whether BOLD-MRI could evaluate hypoxia and angiogenesis of breast invasive ductal carcinoma (IDC). Methods: Ninety-eight female patients with IDC were retrospectively included in this research. All patients underwent breast BOLD-MRI at 3.0 T before surgery. R2* values of BOLD-MRI were measured. The expression of carbonic anhydrase IX (CA IX) and vascular endothelial growth factor (VEGF) was analyzed by immunohistochemistry. Spearman's correlation analysis was used to correlate R2* value with CA IX and VEGF levels. Results: Heterogeneous intensity on BOLD-MRI images was the main finding of IDCs. The mean R2* value was 52.8 ± 18.6 Hz. The R2* values in patients with axillary lymph node metastasis were significantly higher than the R2* values in patients without axillary lymph node metastasis (t = 2.882, P = 0.005). R2* values increased with CA IX level and positively correlated with the level of CA IX (r = 0.616, P < 0.001); however, R2* value had no significantly correlation with the level of VEGF (r = 0.110, P = 0.281). Conclusion: BOLD-MRI could noninvasively evaluate chronic hypoxia of IDC, but not angiogenesis. PMID:28051026

  12. Protective effect of hydrogen-rich water against gentamicin-induced nephrotoxicity in rats using blood oxygenation level-dependent MR imaging.

    PubMed

    Matsushita, Taro; Kusakabe, Yoshinori; Kitamura, Akihiro; Okada, Sakie; Murase, Kenya

    2011-01-01

    We assessed intrarenal oxygenation in gentamicin-induced nephrotoxicity (GIN) and the protective effect of hydrogen-rich water (HW) against GIN using blood oxygenation level-dependent magnetic resonance (MR) imaging. We acquired T(2)*-weighted images (T(2)*WI) of 21 rats on Days 0, 2, 4, and 7 using a 1.5-tesla MR imaging system. The rats were divided into 3 groups of seven each: control rats had free access to standard water and no gentamicin (GM) injection; rats designated the GM group had free access to standard water and were injected with GM (80 mg/kg/day) subcutaneously for 7 days; and the third group, designated the GM+HW group, had free access to HW and were injected with GM. R(2)* (=1/T(2)*) was estimated from T(2)*WI. R(2)* values in the cortex were significantly decreased on Days 2, 4, and 7 compared with those on Day 0 in the GM group but not significantly changed in the control and GM+HW groups. R(2)* values in the medulla did not change significantly in any group. Our findings suggested reduced oxygen utility, mainly in the cortex, in gentamicin-induced nephrotoxicity and an ameliorative effect of hydrogen-rich water against GIN.

  13. Blood oxygen level-dependent (BOLD) MRI: A novel technique for the assessment of myocardial ischemia as identified by nuclear imaging SPECT.

    PubMed

    Egred, M; Waiter, G D; Redpath, T W; Semple, S K I; Al-Mohammad, A; Walton, S

    2007-12-01

    The different levels of deoxyhemoglobin in the ischemic myocardium, induced by stressors such as dipyridamole, can be detected by blood oxygen level-dependent (BOLD) MRI and may be used to diagnose myocardial ischemia. The aim of this study was to assess the signal change in the myocardium on BOLD MRI as well as wall thickening between rest and dipyridamole stress images in ischemic and non-ischemic myocardium as identified on SPECT imaging. Twelve patients with stress-induced myocardial ischemia on SPECT underwent rest and dipyridamole stress MRI using a double breath-hold, T2()-weighted, ECG-gated sequence to produce BOLD contrast images as well as cine-MRI for wall thickening assessment in 10 of the 12 patients. Signal change on BOLD MRI and wall thickening were compared between rest and stress images in ischemic and non-ischemic myocardial segments as identified on SPECT. In each patient, two MRI slices containing 16 segments per slice were analysed. In total, there were 384 segments for BOLD analysis and 320 for wall thickening. For BOLD signal 137 segments correlated to segments with reversible ischemia on SPECT and 247 to normal segments, while for wall thickening 112 segments correlated to segments with reversible ischemia and 208 to normal segments. The average BOLD MRI signal intensity change was -13.8 (+/-16.3)% in the ischemic segments compared to -10.3 (+/-14.7)% in the non-ischemic segments (p=0.05). The average wall thickening was 6.4 (+/-3.4) mm in the ischemic segments compared to 8.7 (+/-3.8) mm in the non-ischemic segments (p<0.0001). Stress-induced ischemic myocardium has a different signal change and wall thickening than non-ischemic myocardium and may be differentiated on BOLD MRI. Larger studies are needed to define a threshold for detection and to determine the sensitivity and specificity of this technique.

  14. Blood oxygenation level-dependent magnetic resonance imaging during carbogen breathing: differentiation between prostate cancer and benign prostate hyperplasia and correlation with vessel maturity.

    PubMed

    Di, Ningning; Mao, Ning; Cheng, Wenna; Pang, Haopeng; Ren, Yan; Wang, Ning; Liu, Xinjiang; Wang, Bin

    2016-01-01

    The aim of this study was to investigate whether the blood oxygenation level-dependent (BOLD) contrast magnetic resonance imaging (MRI) can evaluate tumor maturity and preoperatively differentiate prostate cancer (PCa) from benign prostate hyperplasia (BPH). BOLD MRI based on transverse relaxation time*-weighted echo planar imaging was performed to assess PCa (19) and BPH (22) responses to carbogen (95% O2 and 5% CO2). The average signal values of PCa and BPH before and after carbogen breathing and the relative increased signal values were computed, respectively. The endothelial-cell marker, CD31, and the pericyte marker, α-smooth muscle actin (mature vessels), were detected with immunofluorescence, and were assessed by microvessel density (MVD) and microvessel pericyte density (MPD). The microvessel pericyte coverage index (MPI) was used to evaluate the degree of vascular maturity. The changed signal from BOLD MRI was correlated with MVD, MPD, and MPI. After inhaling carbogen, both PCa and BPH showed an increased signal, but a lower slope was found in PCa than that in BPH (P<0.05). PCa had a higher MPD and MVD but a lower MPI than BPH. The increased signal intensity was positively correlated with MPI in PCa and that in BPH (r=0.616, P=0.011; r=0.658, P=0.002); however, there was no correlation between the increased signal intensity and MPD or MVD in PCa than that in BPH (P>0.05). Our results confirmed that the increased signal values induced by BOLD MRI well differentiated PCa from BPH and had a positive correlation with vessel maturity in both of them. BOLD MRI can be utilized as a surrogate marker for the noninvasive assessment of the degree of vessel maturity.

  15. Measurement of Cerebrovascular Reactivity as Blood Oxygen Level-Dependent Magnetic Resonance Imaging Signal Response to a Hypercapnic Stimulus in Mechanically Ventilated Patients.

    PubMed

    Venkatraghavan, Lashmi; Poublanc, Julien; Han, Jay S; Sobczyk, Olivia; Rozen, Casey; Sam, Kevin; Duffin, James; Mikulis, David J; Fisher, Joseph A

    2017-09-26

    Impaired cerebrovascular reactivity (CVR) is an important prognostic marker of stroke. Most measures of CVR lack (1) a reproducible vasoactive stimulus and (2) a high time and spatial resolution measure of cerebral blood flow (CBF), particularly for mechanically ventilated patients. The aim of our study was to investigate the feasibility of measuring CVR using sequential gas delivery circuit and gas blender for precise targeting of end-tidal PCO2 (PetCO2), and blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) signal as a surrogate of CBF, in mechanically ventilated patients. Four patients with known moyamoya disease requiring preoperative CVR measurements under general anesthesia were studied. All patients had standard anesthesia induction and maintenance with intravenous propofol and rocuronium. Patients were intubated and manually ventilated with a self-inflating bag connected to a sequential breathing circuit. A computer-controlled gas blender supplied the gas mixture in proportions to attain target PetCO2. BOLD-MRI was performed at 3.0 Tesla magnet. Changes in signal per change in PetCO2 were calculated, and their magnitude color-coded and mapped onto the anatomic scan to form CVR maps. CVR studies were successfully performed on all patients, and the CVR values were lower in both gray and white matter bilaterally when compared with healthy volunteers. In addition, CVR maps in 3 patients showed intracerebral steal phenomenon in spite of having had cerebral revascularization procedures, indicating that they are still at risk of cerebral ischemia. BOLD-MRI CVR studies are feasible in mechanically ventilated patients anesthetized with propofol. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  16. CO2 blood oxygen level-dependent MR mapping of cerebrovascular reserve in a clinical population: safety, tolerability, and technical feasibility.

    PubMed

    Spano, Vincent R; Mandell, Daniel M; Poublanc, Julien; Sam, Kevin; Battisti-Charbonney, Anne; Pucci, Olivia; Han, Jay S; Crawley, Adrian P; Fisher, Joseph A; Mikulis, David J

    2013-02-01

    To evaluate the safety, tolerability, and technical feasibility of mapping cerebrovascular reactivity (CVR) in a clinical population by using a precise prospectively targeted CO(2) stimulus and blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging. A chart review was performed of all CVR studies from institutional review board-approved projects at a tertiary care hospital between January 1, 2006, and December 1, 2010. Informed consent was obtained. Records were searched for the incidence of adverse events and failed examinations. CVR maps were evaluated for diagnostic quality by two blinded observers and were categorized as good, diagnostic but suboptimal, or nondiagnostic. Outcomes were presented as raw data and descriptive statistics (means ± standard deviations). Intraclass correlation coefficient was used to determine interobserver variability. Four hundred thirty-four consecutive CVR examinations from 294 patients (51.8% female patients) were studied. Patient age ranged from 9 to 88 years (mean age, 45.9 years ± 20.6). Transient symptoms, such as shortness of breath, headache, and dizziness, were reported in 48 subjects (11.1% of studies) during hypercapnic phases only. There were no neurologic ischemic events, myocardial infarctions, or other major complications. The success rate in generating CVR maps was 83.9% (364 of 434). Of the 70 (16.1%) failed examinations, 25 (35.7%) were due to discomfort; eight (11.4%), to head motion; two (2.9%), to inability to cooperate; seven (10.0%), to technical difficulties with equipment; and 28 (40.0%), to unknown or unspecified conditions. Among the 364 remaining successful examinations, good quality CVR maps were obtained in 340 (93.4%); diagnostic but suboptimal, in 12 (3.3%); and nondiagnostic, in 12 (3.3%). CVR mapping by using a prospectively targeted CO(2) stimulus and BOLD MR imaging is safe, well tolerated, and technically feasible in a clinical patient population.

  17. Relationship Between Changes in the Temporal Dynamics of the Blood-Oxygen-Level-Dependent Signal and Hypoperfusion in Acute Ischemic Stroke.

    PubMed

    Khalil, Ahmed A; Ostwaldt, Ann-Christin; Nierhaus, Till; Ganeshan, Ramanan; Audebert, Heinrich J; Villringer, Kersten; Villringer, Arno; Fiebach, Jochen B

    2017-04-01

    Changes in the blood-oxygen-level-dependent (BOLD) signal provide a noninvasive measure of blood flow, but a detailed comparison with established perfusion parameters in acute stroke is lacking. We investigated the relationship between BOLD signal temporal delay and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) in stroke patients. In 30 patients with acute (<24 hours) ischemic stroke, we performed Pearson correlation and multiple linear regression between DSC-MRI parameters (time to maximum [Tmax], mean transit time, cerebral blood flow, and cerebral blood volume) and BOLD-based parameters (BOLD delay and coefficient of BOLD variation). Prediction of severe hypoperfusion (Tmax >6 seconds) was assessed using receiver-operator characteristic (ROC) analysis. Correlation was highest between Tmax and BOLD delay (venous sinus reference; time shift range 7; median r=0.60; interquartile range=0.49-0.71). Coefficient of BOLD variation correlated with cerebral blood volume (median r= 0.37; interquartile range=0.24-0.51). Mean R(2) for predicting BOLD delay by DSC-MRI was 0.54 (SD=0.2) and for predicting coefficient of BOLD variation was 0.37 (SD=0.17). BOLD delay (whole-brain reference, time shift range 3) had an area under the curve of 0.76 for predicting severe hypoperfusion (sensitivity=69.2%; specificity=80%), whereas BOLD delay (venous sinus reference, time shift range 3) had an area under the curve of 0.76 (sensitivity=67.3%; specificity=83.5%). BOLD delay is related to macrovascular delay and microvascular hypoperfusion, can identify severely hypoperfused tissue in acute stroke, and is a promising alternative to gadolinium contrast agent-based perfusion assessment in acute stroke. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00715533 and NCT02077582. © 2017 American Heart Association, Inc.

  18. Noninvasive Monitoring of Microvascular Changes With Partial Irradiation Using Dynamic Contrast-Enhanced and Blood Oxygen Level-Dependent Magnetic Resonance Imaging

    SciTech Connect

    Lin, Yu-Chun; Wang, Jiun-Jie; Hong, Ji-Hong; Lin, Yi-Ping; Lee, Chung-Chi; Wai, Yau-Yau; Ng, Shu-Hang; Wu, Yi-Ming; Wang, Chun-Chieh

    2013-04-01

    Purpose: The microvasculature of a tumor plays an important role in its response to radiation therapy. Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) and blood oxygen level-dependent (BOLD) MRI are both sensitive to vascular characteristics. The present study proposed a partial irradiation approach to a xenograft tumor to investigate the intratumoral response to radiation therapy using DCE and BOLD MRI. Methods and Materials: TRAMP-C1 tumors were grown in C57BL/6J mice. Partial irradiation was performed on the distal half of the tumor with a single dose of 15 Gy. DCE MRI was performed to derive the endothelium transfer constant, K{sup trans}, using pharmacokinetic analysis. BOLD MRI was performed using quantitative R2* measurements with carbogen breathing. The histology of the tumor was analyzed using hematoxylin and eosin staining and CD31 staining to detect endothelial cells. The differences between the irradiated and nonirradiated regions of the tumor were assessed using K{sup trans} values, ΔR2* values in response to carbogen and microvascular density (MVD) measurements. Results: A significantly increased K{sup trans} and reduced BOLD response to carbogen were found in the irradiated region of the tumor compared with the nonirradiated region (P<.05). Histologic analysis showed a significant aggregation of giant cells and a reduced MVD in the irradiated region of the tumor. The radiation-induced difference in the BOLD response was associated with differences in MVD and K{sup trans}. Conclusions: We demonstrated that DCE MRI and carbogen-challenge BOLD MRI can detect differential responses within a tumor that may potentially serve as noninvasive imaging biomarkers to detect microvascular changes in response to radiation therapy.

  19. Quantification of myocardial oxygenation in heart failure using blood-oxygen-level-dependent T2* magnetic resonance imaging: Comparison with cardiopulmonary exercise test.

    PubMed

    Nagao, Michinobu; Yamasaki, Yuzo; Kawanami, Satoshi; Kamitani, Takeshi; Sagiyama, Koji; Higo, Taiki; Ide, Tomomi; Takemura, Atsushi; Ishizaki, Umiko; Fukushima, Kenji; Watanabe, Yuji; Honda, Hiroshi

    2017-06-01

    Quantification of myocardial oxygenation (MO) in heart failure (HF) has been less than satisfactory. This has necessitated the use of invasive techniques to measure MO directly or to determine the oxygen demand during exercise using the cardiopulmonary exercise (CPX) test. We propose a new quantification method for MO using blood-oxygen-level-dependent (BOLD) myocardial T2* magnetic resonance imaging (M-T2* MRI), and investigate its correlation with CPX results. Thirty patients with refractory HF who underwent cardiac MRI and CPX test for heart transplantation, and 24 healthy, age-matched volunteers as controls were enrolled. M-T2* imaging was performed using a 3-Tesla and multi-echo gradient-echo sequence. M-T2* was calculated by fitting the signal intensity data for the mid-left ventricular septum to a decay curve. M-T2* was measured under room-air (T2*-air) and after inhalation of oxygen for 10min at a flow rate of 10L/min (T2*-oxy). MO was defined as the difference between the two values (ΔT2*). Changes in M-T2* at the two conditions and ΔT2* between the two groups were compared. Correlation between ΔT2* and CPX results was analyzed using the Pearson coefficient. T2*-oxy was significantly greater than T2*-air in patients with HF (29.9±7.3ms vs. 26.7±6.0ms, p<0.001), whereas no such difference was observed in controls (25.5±4.0ms vs. 25.4±4.4ms). ΔT2* was significantly greater for patients with HF than for controls (3.2±4.5ms vs. -0.1±1.3ms, p<0.001). A significant correlation between ΔT2* and CPX results (peak VO2, r=-0.46, p<0.05; O2 pulse, r=-0.54, p<0.005) was observed. ΔT2* is increased T2*-oxy is greater in patients with HF, and is correlated with oxygen metabolism during exercise as measured by the CPX test. Hence, ΔT2* can be used as a surrogate marker of MO instead of CPX test. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. T2-prepared steady-state free precession blood oxygen level-dependent MR imaging of myocardial perfusion in a dog stenosis model.

    PubMed

    Shea, Steven M; Fieno, David S; Schirf, Brian E; Bi, Xiaoming; Huang, Jie; Omary, Reed A; Li, Debiao

    2005-08-01

    To assess the ability of a T2-prepared steady-state free precession blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging sequence to depict changes in myocardial perfusion during stress testing in a dog stenosis model. Study was approved by the institutional Animal Care and Use Committee. A hydraulic occluder was placed in the left circumflex coronary artery (LCX) in 10 dogs. Adenosine was administered intravenously to increase coronary blood flow, and stenosis was achieved in the LCX with the occluder. A T2-prepared two-dimensional steady-state free precession sequence was used for BOLD imaging at a spatial resolution of 1.5 x 1.2 x 5.0 mm3, and first-pass perfusion images were acquired for visual comparison. Microspheres were injected to provide regional perfusion information. Mixed-effect regression analysis was performed to assess normalized MR signal intensity ratios and microsphere-measured perfusion differences. For the same data, 95% prediction intervals were calculated to determine the smallest perfusion change detectable. Means +/- standard deviations were calculated for myocardial regional comparison data. A two-tailed Student t test was used to determine if significant differences (P < .01) existed between different myocardial regions. Under maximal adenosine stress, MR clearly depicted stenotic regions and showed regional signal differences between the left anterior descending coronary artery (LAD)-fed myocardium and the stenosed LCX-fed myocardium. Visual comparisons with first-pass images were also excellent. Regional MR signal intensity differences between LAD and LCX-fed myocardium (1.24 +/- 0.08) were significantly different (P < .01) from differences between LAD and septal-fed myocardium (1.02 +/- 0.07), which was in agreement with microsphere-measured flow differences (LAD/LCX, 3.38 +/- 0.83; LAD/septal, 1.26 +/- 0.49). The linear mixed-effect regression model showed good correlation (R = 0.79) between MR differences and

  1. Longitudinal Assessment of Renal Perfusion and Oxygenation in Transplant Donor-Recipient Pairs Using Arterial Spin Labeling and Blood Oxygen Level-Dependent Magnetic Resonance Imaging.

    PubMed

    Niles, David J; Artz, Nathan S; Djamali, Arjang; Sadowski, Elizabeth A; Grist, Thomas M; Fain, Sean B

    2016-02-01

    The aims of this study were to assess renal function in kidney transplant recipients and their respective donors over 2 years using arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and to prospectively evaluate the effect of losartan on functional MRI measures in recipients. The study included 15 matched pairs of renal transplant donors and recipients. Arterial spin labeling and BOLD MRI of the kidneys were performed on donors before transplant surgery (baseline) and on both donors and recipients at 3 months, 1 year, and 2 years after transplant. After 3 months, 7 of the 15 recipients were prescribed 25 to 50 mg/d losartan for the remainder of the study. A linear mixed-effects model was used to evaluate perfusion, R2*, estimated glomerular filtration rate, and fractional excretion of sodium for changes across time or associated with losartan treatment. In donors, cortical perfusion in the remaining kidney decreased by 50 ± 19 mL/min per 100 g (11.8%) between baseline and 2 years (P < 0.05), while cortical R2* declined modestly by 0.7 ± 0.3 s-1 (5.6%; P < 0.05). In transplanted kidneys, cortical perfusion decreased markedly by 141 ± 21 mL/min per 100 g (34.2%) between baseline and 2 years (P < 0.001), while medullary R2* declined by 1.5 ± 0.8 s-1 (8.3%; P = 0.06). Single-kidney estimated glomerular filtration rate increased between baseline and 2 years by 17.7 ± 2.7 mL/min per 1.73 m (40.3%; P < 0.0001) in donors and to 14.6 ± 4.3 mL/min per 1.73 m (33.3%; P < 0.01) in recipients. Cortical perfusion at 1 and 2 years in recipients receiving 25 to 50 mg/d losartan was 62 ± 24 mL/min per 100 g higher than recipients not receiving the drug (P < 0.05). No significant effects of losartan were observed for any other markers of renal function. The results suggest an important role for noninvasive functional monitoring with ASL and BOLD MRI in kidney transplant recipients and donors, and they indicate a potentially

  2. KCC2 Gates Activity-Driven AMPA Receptor Traffic through Cofilin Phosphorylation.

    PubMed

    Chevy, Quentin; Heubl, Martin; Goutierre, Marie; Backer, Stéphanie; Moutkine, Imane; Eugène, Emmanuel; Bloch-Gallego, Evelyne; Lévi, Sabine; Poncer, Jean Christophe

    2015-12-02

    Expression of the neuronal K/Cl transporter KCC2 is tightly regulated throughout development and by both normal and pathological neuronal activity. Changes in KCC2 expression have often been associated with altered chloride homeostasis and GABA signaling. However, recent evidence supports a role of KCC2 in the development and function of glutamatergic synapses through mechanisms that remain poorly understood. Here we show that suppressing KCC2 expression in rat hippocampal neurons precludes long-term potentiation of glutamatergic synapses specifically by preventing activity-driven membrane delivery of AMPA receptors. This effect is independent of KCC2 transporter function and can be accounted for by increased Rac1/PAK- and LIMK-dependent cofilin phosphorylation and actin polymerization in dendritic spines. Our results demonstrate that KCC2 plays a critical role in the regulation of spine actin cytoskeleton and gates long-term plasticity at excitatory synapses in cortical neurons.

  3. NFAT regulates pre-synaptic development and activity-dependent plasticity in Drosophila

    PubMed Central

    Freeman, Amanda; Franciscovich, Amy; Bowers, Mallory; Sandstrom, David J.; Sanyal, Subhabrata

    2010-01-01

    The calcium-regulated transcription factor NFAT is emerging as a key regulator of neuronal development and plasticity but precise cellular consequences of NFAT function remain poorly understood. Here, we report that the single Drosophila NFAT homolog is widely expressed in the nervous system including motor neurons and unexpectedly controls neural excitability. Likely due to this effect on excitability, NFAT regulates overall larval locomotion and both chronic and acute forms of activity-dependent plasticity at the larval glutamatergic neuro-muscular synapse. Specifically, NFAT-dependent synaptic phenotypes include changes in the number of pre-synaptic boutons, stable modifications in synaptic microtubule architecture and pre-synaptic transmitter release, while no evidence is found for synaptic retraction or alterations in the level of the synaptic cell adhesion molecule FasII. We propose that NFAT regulates pre-synaptic development and constraints long-term plasticity by dampening neuronal excitability. PMID:21185939

  4. Nutrient-intake-level-dependent regulation of intestinal development in newborn intrauterine growth-restricted piglets via glucagon-like peptide-2.

    PubMed

    Liu, J; Liu, Z; Gao, L; Chen, L; Zhang, H

    2016-10-01

    The objective of the present study was to investigate the intestinal development of newborn intrauterine growth-restricted (IUGR) piglets subjected to normal nutrient intake (NNI) or restricted nutrient intake (RNI). Newborn normal birth weight (NBW) and IUGR piglets were allotted to NNI or RNI levels for 4 weeks from day 8 postnatal. IUGR piglets receiving NNI had similar growth performance compared with that of NBW piglets. Small intestine length and villous height were greater in IUGR piglets fed the NNI than that of piglets fed the RNI. Lactase activity was increased in piglets fed the NNI compared with piglets fed the RNI. Absorptive function, represented by active glucose transport by the Ussing chamber method and messenger RNA (mRNA) expressions of two main intestinal glucose transporters, Na+-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2), were greater in IUGR piglets fed the NNI compared with piglets fed the RNI regimen. The apoptotic process, characterized by caspase-3 activity (a sign of activated apoptotic cells) and mRNA expressions of p53 (pro-apoptotic), bcl-2-like protein 4 (Bax) (pro-apoptotic) and B-cell lymphoma-2 (Bcl-2) (anti-apoptotic), were improved in IUGR piglets fed the NNI regimen. To test the hypothesis that improvements in intestinal development of IUGR piglets fed NNI might be mediated through circulating glucagon-like peptide-2 (GLP-2), GLP-2 was injected subcutaneously to IUGR piglets fed the RNI from day 8 to day 15 postnatal. Although the intestinal development of IUGR piglets fed the RNI regimen was suppressed compared with those fed the NNI regimen, an exogenous injection of GLP-2 was able to bring intestinal development to similar levels as NNI-fed IUGR piglets. Collectively, our results demonstrate that IUGR neonates that have NNI levels could improve intestinal function via the regulation of GLP-2.

  5. BDNF Val66Met polymorphism influence on striatal blood-level-dependent response to monetary feedback depends on valence and agency.

    PubMed

    Chumbley, J; Späti, J; Dörig, N; Brakowski, J; Grosse Holtforth, M; Seifritz, E; Spinelli, S

    2014-11-07

    Animal work implicates the brain-derived neurotrophic factor (BDNF) in function of the ventral striatum (VS), a region known for its role in processing valenced feedback. Recent evidence in humans shows that BDNF Val66Met polymorphism modulates VS activity in anticipation of monetary feedback. However, it remains unclear whether the polymorphism impacts the processing of self-attributed feedback differently from feedback attributed to an external agent. In this study, we emphasize the importance of the feedback attribution because agency is central to computational accounts of the striatum and cognitive accounts of valence processing. We used functional magnetic resonance imaging and a task, in which financial gains/losses are either attributable to performance (self-attributed, SA) or chance (externally-attributed, EA) to ask whether BDNF Val66Met polymorphism predicts VS activity. We found that BDNF Val66Met polymorphism influenced how feedback valence and agency information were combined in the VS and in the right inferior frontal junction (IFJ). Specifically, Met carriers' VS response to valenced feedback depended on agency information, while Val/Val carriers' VS response did not. This context-specific modulation of valence effectively amplified VS responses to SA losses in Met carriers. The IFJ response to SA losses also differentiated Val/Val from Met carriers. These results may point to a reduced allocation of attention and altered motivational salience to SA losses in Val/Val compared to Met carriers. Implications for major depressive disorder are discussed.

  6. Cocaine-associated odor cue re-exposure increases blood oxygenation level dependent signal in memory and reward regions of the maternal rat brain.

    PubMed

    Caffrey, Martha K; Febo, Marcelo

    2014-01-01

    Cue triggered relapse during the postpartum period can negatively impact maternal care. Given the high reward value of pups in maternal rats, we designed an fMRI experiment to test whether offspring presence reduces the neural response to a cocaine associated olfactory cue. Cocaine conditioned place preference was carried out before pregnancy in the presence of two distinct odors that were paired with cocaine or saline (+Cue and -Cue). The BOLD response to +Cue and -Cue was measured in dams on postpartum days 2-4. Odor cues were delivered to dams in the absence and then the presence of pups. Our data indicate that several limbic and cognitive regions of the maternal rat brain show a greater BOLD signal response to a +Cue versus -Cue. These include dorsal striatum, prelimbic cortex, parietal cortex, habenula, bed nucleus of stria terminalis, lateral septum and the mediodorsal and the anterior thalamic nucleus. Of the aforementioned brain regions, only the parietal cortex of cocaine treated dams showed a significant modulatory effect of pup presence. In this area of the cortex, cocaine exposed maternal rats showed a greater BOLD activation in response to the +Cue in the presence than in the absence of pups. Specific regions of the cocaine exposed maternal rat brain are strongly reactive to drug associated cues. The regions implicated in cue reactivity have been previously reported in clinical imaging work, and previous work supports their role in various motivational and cognitive functions. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  7. COCAINE-ASSOCIATED ODOR CUE RE-EXPOSURE INCREASES BLOOD OXYGENATION LEVEL DEPENDENT SIGNAL IN MEMORY AND REWARD REGIONS OF THE MATERNAL RAT BRAIN*

    PubMed Central

    Caffrey, Martha K.; Febo, Marcelo

    2013-01-01

    BACKGROUND Cue triggered relapse during the postpartum period can negatively impact maternal care. Given the high reward value of pups in maternal rats, we designed an fMRI experiment to test whether offspring presence reduces the neural response to a cocaine associated olfactory cue. METHODS Cocaine conditioned place preference was carried out before pregnancy in the presence of two distinct odors that were paired with cocaine or saline (+Cue and −Cue). The BOLD response to +Cue and −Cue was measured in dams on postpartum days 2–4. Odor cues were delivered to dams in the absence and then the presence of pups. RESULTS Our data indicate that several limbic and cognitive regions of the maternal rat brain show a greater BOLD signal response to a +Cue versus −Cue. These include dorsal striatum, prelimbic cortex, parietal cortex, habenula, bed nucleus of stria terminalis, lateral septum and the mediodorsal and the anterior thalamic nucleus. Of the aforementioned brain regions, only the parietal cortex of cocaine treated dams showed a significant modulatory effect of pup presence. In this area of the cortex, cocaine exposed maternal rats showed a greater BOLD activation in response to the +Cue in the presence than in the absence of pups. CONCLUSIONS Specific regions of the cocaine exposed maternal rat brain are strongly reactive to drug associated cues. The regions implicated in cue reactivity have been previously reported in clinical imaging work, and previous work supports their role in various motivational and cognitive functions. PMID:24183499

  8. Activity.

    ERIC Educational Resources Information Center

    Clearing: Nature and Learning in the Pacific Northwest, 1984

    1984-01-01

    Presents three activities: (1) investigating succession in a schoolground; (2) investigating oak galls; and (3) making sun prints (photographs made without camera or darkroom). Each activity includes a list of materials needed and procedures used. (JN)

  9. Effects of hypercapnia, hypocapnia, and hyperoxemia on blood oxygenation level-dependent signal intensity determined by use of susceptibility-weighted magnetic resonance imaging in isoflurane-anesthetized dogs.

    PubMed

    Rioja, Eva; Kerr, Carolyn L; McDonell, Wayne N; Dobson, Howard; Konyer, Norman B; Poma, Roberto; Noseworthy, Michael D

    2010-01-01

    To assess the effects of alterations in PaCO(2) and PaO(2) on blood oxygenation level-dependent (BOLD) signal intensity determined by use of susceptibility-weighted magnetic resonance imaging in brains of isoflurane-anesthetized dogs. 6 healthy dogs. In each dog, anesthesia was induced with propofol (6 to 8 mg/kg, IV) and maintained with isoflurane (1.7%) and atracurium (0.2 mg/kg, IV, q 30 min). During 1 magnetic resonance imaging session in each dog, targeted values of PaCO(2) (20, 40, or 80 mm Hg) and PaO(2) (100 or 500 mm Hg) were combined to establish 6 experimental conditions, including a control condition (PaCO(2), 40 mm Hg; PaO(2), 100 mm Hg). Dogs were randomly assigned to different sequences of conditions. Each condition was established for a period of >or= 5 minutes before susceptibility-weighted imaging was performed. Signal intensity was measured in 6 regions of interest in the brain, and data were analyzed by use of an ANCOVA and post hoc Tukey-Kramer adjustments. Compared with control condition findings, BOLD signal intensity did not differ significantly in any region of interest. However, signal intensities in the thalamus and diencephalic gray matter decreased significantly during both hypocapnic conditions, compared with all other conditions except for the control condition. In isoflurane-anesthetized dogs, certain regions of gray matter appeared to have greater cerebrovascular responses to changes in PaCO(2) and PaO(2) than did others. Both PaO(2) and PaCO(2) should be controlled during magnetic resonance imaging procedures that involve BOLD signaling and taken into account when interpreting findings.

  10. Activities.

    ERIC Educational Resources Information Center

    Hirsch, Christian R., Ed.; And Others

    1987-01-01

    An activity is described as an example of an application that draws on the behavior of current in electrical circuits to create a symbolic algebra. Five worksheets are included, with discussion of their use. (MNS)

  11. Activities.

    ERIC Educational Resources Information Center

    Prichard, Mary Kim, Ed.; And Others

    1990-01-01

    Presented are several applications of geometric concepts and measurement skills that are used daily by surveyors, real estate attorneys, and paralegal assistants. Described are the objectives and directions for this lesson. Activity sheets for students are included. (CW)

  12. Activities.

    ERIC Educational Resources Information Center

    Bippert, Judy

    1993-01-01

    Presents activities designed to give students an opportunity to solve concrete problems involving spatial relationships and logical thinking utilizing hands-on manipulatives. Provides teacher instructions and four reproducible worksheets. (MDH)

  13. Blood oxygenation level-dependent (BOLD) total and extravascular signal changes and ΔR2* in human visual cortex at 1.5, 3.0 and 7.0 T.

    PubMed

    Donahue, Manus J; Hoogduin, Hans; van Zijl, Peter C M; Jezzard, Peter; Luijten, Peter R; Hendrikse, Jeroen

    2011-01-01

    The characterisation of the extravascular (EV) contribution to the blood oxygenation level-dependent (BOLD) effect is important for understanding the spatial specificity of BOLD contrast and for modelling approaches that aim to extract quantitative metabolic parameters from the BOLD signal. Using bipolar crusher gradients, total (b = 0 s/mm(2) ) and predominantly EV (b = 100 s/mm(2) ) gradient echo BOLD ΔR(2)* and signal changes (ΔS/S) in response to visual stimulation (flashing checkerboard; f = 8 Hz) were investigated sequentially (within < 3 h) at 1.5, 3.0 and 7.0 T in the same subgroup of healthy volunteers (n = 7) and at identical spatial resolutions (3.5 × 3.5 × 3.5 mm(3)). Total ΔR(2)* (z-score analysis) values were -0.61 ± 0.10 s(-1) (1.5 T), -0.74 ± 0.05 s(-1) (3.0 T) and -1.37 ± 0.12 s(-1) (7.0 T), whereas EV ΔR(2)* values were -0.28 ± 0.07 s(-1) (1.5 T), -0.52 ± 0.07 s(-1) (3.0 T) and -1.25 ± 0.11 s(-1) (7.0 T). Although EV ΔR(2)* increased linearly with field, as expected, it was found that EV ΔS/S increased less than linearly with field in a manner that varied with TE choice. Furthermore, unlike ΔR(2)*, total and EV ΔS/S did not converge at 7.0 T. These trends were similar whether a z-score analysis or occipital lobe-based region-of-interest approach was used for voxel selection. These findings suggest that calibrated BOLD approaches may benefit from an EV ΔR(2)* measurement as opposed to a ΔS/S measurement at a single TE.

  14. Activities.

    ERIC Educational Resources Information Center

    Kincaid, Charlene; And Others

    1993-01-01

    Presents an activity in which students collect and organize data from a real-world simulation of the scientific concept of half life. Students collect data using a marble sifter, analyze the data using a graphing calculator, and determine an appropriate mathematical model. Includes reproducible worksheets. (MDH)

  15. Activities.

    ERIC Educational Resources Information Center

    Kincaid, Charlene; And Others

    1993-01-01

    Presents an activity in which students collect and organize data from a real-world simulation of the scientific concept of half life. Students collect data using a marble sifter, analyze the data using a graphing calculator, and determine an appropriate mathematical model. Includes reproducible worksheets. (MDH)

  16. Unc-51 controls active zone density and protein composition by downregulating ERK signaling.

    PubMed

    Wairkar, Yogesh P; Toda, Hirofumi; Mochizuki, Hiroaki; Furukubo-Tokunaga, Katsuo; Tomoda, Toshifumi; Diantonio, Aaron

    2009-01-14

    Efficient synaptic transmission requires the apposition of neurotransmitter release sites opposite clusters of postsynaptic neurotransmitter receptors. Transmitter is released at active zones, which are composed of a large complex of proteins necessary for synaptic development and function. Many active zone proteins have been identified, but little is known of the mechanisms that ensure that each active zone receives the proper complement of proteins. Here we use a genetic analysis in Drosophila to demonstrate that the serine threonine kinase Unc-51 acts in the presynaptic motoneuron to regulate the localization of the active zone protein Bruchpilot opposite to glutamate receptors at each synapse. In the absence of Unc-51, many glutamate receptor clusters are unapposed to Bruchpilot, and ultrastructural analysis demonstrates that fewer active zones contain dense body T-bars. In addition to the presence of these aberrant synapses, there is also a decrease in the density of all synapses. This decrease in synaptic density and abnormal active zone composition is associated with impaired evoked transmitter release. Mechanistically, Unc-51 inhibits the activity of the MAP kinase ERK to promote synaptic development. In the unc-51 mutant, increased ERK activity leads to the decrease in synaptic density and the absence of Bruchpilot from many synapses. Hence, activated ERK negatively regulates synapse formation, resulting in either the absence of active zones or the formation of active zones without their proper complement of proteins. The Unc-51-dependent inhibition of ERK activity provides a potential mechanism for synapse-specific control of active zone protein composition and release probability.

  17. Activity-dependent regulation of release probability at excitatory hippocampal synapses: a crucial role of FMRP in neurotransmission

    PubMed Central

    Wang, Xiao-Sheng; Peng, Chun-Zi; Cai, Wei-Jun; Xia, Jian; Jin, Daozhong; Dai, Yuqiao; Luo, Xue-Gang; Klyachko, Vitaly A.; Deng, Pan-Yue

    2014-01-01

    Transcriptional silencing of the Fmr1 gene encoding fragile X mental retardation protein (FMRP) causes Fragile X Syndrome (FXS), the most common form of inherited intellectual disability and the leading genetic cause of autism. FMRP has been suggested to play important roles in regulating neurotransmission and short-term synaptic plasticity at excitatory hippocampal and cortical synapses. However, the origins and the mechanisms of these FMRP actions remain incompletely understood, and the role of FMRP in regulating synaptic release probability and presynaptic function remains debated. Here we used variance-mean analysis and peak scaled nonstationary variance analysis to examine changes in both pre- and postsynaptic parameters during repetitive activity at excitatory CA3-CA1 hippocampal synapses in a mouse model of FXS. Our analyses revealed that loss of FMRP did not affect the basal release probability or basal synaptic transmission, but caused an abnormally elevated release probability specifically during repetitive activity. These abnormalities were not accompanied by changes in EPSC kinetics, quantal size or postsynaptic AMPA receptor conductance. Our results thus indicate that FMRP regulates neurotransmission at excitatory hippocampal synapses specifically during repetitive activity via modulation of release probability in a presynaptic manner. Our study suggests that FMRP function in regulating neurotransmitter release is an activity-dependent phenomenon that may contribute to the pathophysiology of FXS. PMID:24646437

  18. Identification of the novel activity-driven interaction between synaptotagmin 1 and presenilin 1 links calcium, synapse, and amyloid beta.

    PubMed

    Kuzuya, Akira; Zoltowska, Katarzyna M; Post, Kathryn L; Arimon, Muriel; Li, Xuejing; Svirsky, Sarah; Maesako, Masato; Muzikansky, Alona; Gautam, Vivek; Kovacs, Dora; Hyman, Bradley T; Berezovska, Oksana

    2016-03-31

    Synaptic loss strongly correlates with memory deterioration. Local accumulation of amyloid β (Aβ) peptide, and neurotoxic Aβ42 in particular, due to abnormal neuronal activity may underlie synaptic dysfunction, neurodegeneration, and memory impairments. To gain an insight into molecular events underlying neuronal activity-regulated Aβ production at the synapse, we explored functional outcomes of the newly discovered calcium-dependent interaction between Alzheimer's disease-associated presenilin 1 (PS1)/γ-secretase and synaptic vesicle proteins. Mass spectrometry screen of mouse brain lysates identified synaptotagmin 1 (Syt1) as a novel synapse-specific PS1-binding partner that shows Ca(2+)-dependent PS1 binding profiles in vitro and in vivo. We found that Aβ level, and more critically, conformation of the PS1 and the Aβ42/40 ratio, are affected by Syt1 overexpression or knockdown, indicating that Syt1 and its interaction with PS1 might regulate Aβ production at the synapse. Moreover, β-secretase 1 (BACE1) stability, β- and γ-secretase activity, as well as intracellular compartmentalization of PS1 and BACE1, but not of amyloid precursor protein (APP), nicastrin (Nct), presenilin enhancer 2 (Pen-2), or synaptophysin (Syp) were altered in the absence of Syt1, suggesting a selective effect of Syt1 on PS1 and BACE1 trafficking. Our findings identify Syt1 as a novel Ca(2+)-sensitive PS1 modulator that could regulate synaptic Aβ, opening avenues for novel and selective synapse targeting therapeutic strategies.

  19. Activity-dependent regulation of release probability at excitatory hippocampal synapses: a crucial role of fragile X mental retardation protein in neurotransmission.

    PubMed

    Wang, Xiao-Sheng; Peng, Chun-Zi; Cai, Wei-Jun; Xia, Jian; Jin, Daozhong; Dai, Yuqiao; Luo, Xue-Gang; Klyachko, Vitaly A; Deng, Pan-Yue

    2014-05-01

    Transcriptional silencing of the Fmr1 gene encoding fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS), the most common form of inherited intellectual disability and the leading genetic cause of autism. FMRP has been suggested to play important roles in regulating neurotransmission and short-term synaptic plasticity at excitatory hippocampal and cortical synapses. However, the origins and mechanisms of these FMRP actions remain incompletely understood, and the role of FMRP in regulating synaptic release probability and presynaptic function remains debated. Here we used variance-mean analysis and peak-scaled nonstationary variance analysis to examine changes in both presynaptic and postsynaptic parameters during repetitive activity at excitatory CA3-CA1 hippocampal synapses in a mouse model of FXS. Our analyses revealed that loss of FMRP did not affect the basal release probability or basal synaptic transmission, but caused an abnormally elevated release probability specifically during repetitive activity. These abnormalities were not accompanied by changes in excitatory postsynaptic current kinetics, quantal size or postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor conductance. Our results thus indicate that FMRP regulates neurotransmission at excitatory hippocampal synapses specifically during repetitive activity via modulation of release probability in a presynaptic manner. Our study suggests that FMRP function in regulating neurotransmitter release is an activity-dependent phenomenon that may contribute to the pathophysiology of FXS.

  20. Improving the spatial accuracy in functional magnetic resonance imaging (fMRI) based on the blood oxygenation level dependent (BOLD) effect: benefits from parallel imaging and a 32-channel head array coil at 1.5 Tesla.

    PubMed

    Fellner, C; Doenitz, C; Finkenzeller, T; Jung, E M; Rennert, J; Schlaier, J

    2009-01-01

    Geometric distortions and low spatial resolution are current limitations in functional magnetic resonance imaging (fMRI). The aim of this study was to evaluate if application of parallel imaging or significant reduction of voxel size in combination with a new 32-channel head array coil can reduce those drawbacks at 1.5 T for a simple hand motor task. Therefore, maximum t-values (tmax) in different regions of activation, time-dependent signal-to-noise ratios (SNR(t)) as well as distortions within the precentral gyrus were evaluated. Comparing fMRI with and without parallel imaging in 17 healthy subjects revealed significantly reduced geometric distortions in anterior-posterior direction. Using parallel imaging, tmax only showed a mild reduction (7-11%) although SNR(t) was significantly diminished (25%). In 7 healthy subjects high-resolution (2 x 2 x 2 mm3) fMRI was compared with standard fMRI (3 x 3 x 3 mm3) in a 32-channel coil and with high-resolution fMRI in a 12-channel coil. The new coil yielded a clear improvement for tmax (21-32%) and SNR(t) (51%) in comparison with the 12-channel coil. Geometric distortions were smaller due to the smaller voxel size. Therefore, the reduction in tmax (8-16%) and SNR(t) (52%) in the high-resolution experiment seems to be tolerable with this coil. In conclusion, parallel imaging is an alternative to reduce geometric distortions in fMRI at 1.5 T. Using a 32-channel coil, reduction of the voxel size might be the preferable way to improve spatial accuracy.

  1. ELKS1 localizes the synaptic vesicle priming protein bMunc13-2 to a specific subset of active zones.

    PubMed

    Kawabe, Hiroshi; Mitkovski, Miso; Kaeser, Pascal S; Hirrlinger, Johannes; Opazo, Felipe; Nestvogel, Dennis; Kalla, Stefan; Fejtova, Anna; Verrier, Sophie E; Bungers, Simon R; Cooper, Benjamin H; Varoqueaux, Frederique; Wang, Yun; Nehring, Ralf B; Gundelfinger, Eckart D; Rosenmund, Christian; Rizzoli, Silvio O; Südhof, Thomas C; Rhee, Jeong-Seop; Brose, Nils

    2017-03-06

    Presynaptic active zones (AZs) are unique subcellular structures at neuronal synapses, which contain a network of specific proteins that control synaptic vesicle (SV) tethering, priming, and fusion. Munc13s are core AZ proteins with an essential function in SV priming. In hippocampal neurons, two different Munc13s-Munc13-1 and bMunc13-2-mediate opposite forms of presynaptic short-term plasticity and thus differentially affect neuronal network characteristics. We found that most presynapses of cortical and hippocampal neurons contain only Munc13-1, whereas ∼10% contain both Munc13-1 and bMunc13-2. Whereas the presynaptic recruitment and activation of Munc13-1 depends on Rab3-interacting proteins (RIMs), we demonstrate here that bMunc13-2 is recruited to synapses by the AZ protein ELKS1, but not ELKS2, and that this recruitment determines basal SV priming and short-term plasticity. Thus, synapse-specific interactions of different Munc13 isoforms with ELKS1 or RIMs are key determinants of the molecular and functional heterogeneity of presynaptic AZs.

  2. Ryanodine Receptor Activation Induces Long-Term Plasticity of Spine Calcium Dynamics

    PubMed Central

    Pannasch, Ulrike; Rückl, Martin; Rüdiger, Sten; Schmitz, Dietmar

    2015-01-01

    A key feature of signalling in dendritic spines is the synapse-specific transduction of short electrical signals into biochemical responses. Ca2+ is a major upstream effector in this transduction cascade, serving both as a depolarising electrical charge carrier at the membrane and an intracellular second messenger. Upon action potential firing, the majority of spines are subject to global back-propagating action potential (bAP) Ca2+ transients. These transients translate neuronal suprathreshold activation into intracellular biochemical events. Using a combination of electrophysiology, two-photon Ca2+ imaging, and modelling, we demonstrate that bAPs are electrochemically coupled to Ca2+ release from intracellular stores via ryanodine receptors (RyRs). We describe a new function mediated by spine RyRs: the activity-dependent long-term enhancement of the bAP-Ca2+ transient. Spines regulate bAP Ca2+ influx independent of each other, as bAP-Ca2+ transient enhancement is compartmentalized and independent of the dendritic Ca2+ transient. Furthermore, this functional state change depends exclusively on bAPs travelling antidromically into dendrites and spines. Induction, but not expression, of bAP-Ca2+ transient enhancement is a spine-specific function of the RyR. We demonstrate that RyRs can form specific Ca2+ signalling nanodomains within single spines. Functionally, RyR mediated Ca2+ release in these nanodomains induces a new form of Ca2+ transient plasticity that constitutes a spine specific storage mechanism of neuronal suprathreshold activity patterns. PMID:26098891

  3. Characterization of the Charge-Level Dependence of CTE losses

    NASA Astrophysics Data System (ADS)

    Anderson, Jay

    2013-10-01

    This internal calibration program will use the charge-injection capability of WFC3/UVIS to explore CTE losses as a function of position and charge-level across the detector. The idea is that the pixel-based CTE-reconstruction model we have in hand characterizes average CTE losses across the detector in terms of the number of traps in each column that affect each Nth electron in a pixel cloud. In actuality, the traps are not uniformly distributed across the detector: most pixels have no traps, but some pixels {probably} have several traps. In addition, the traps that are present are not all the same: some affect the first electron, some the second, some the hundredth, etc, depending on exactly where each trap lies within the silicon of the pixel relative to the resting or shuffling pixel cloud.We can use the charge-injection images to characterize the location and level of traps. The CI level puts about 15,000 electrons into each injected column. In CI images with no background, we can study the losses in the injected column and the gains in the upstream trail to characterize where there are traps that grap the 1st through the 15,000th electron. Most traps affect electrons below this, so this is a pretty broad characterization of the overall trap locations. We of course do not know exactly which pixel the traps are in, but we do know that there may be more in one column than in another, and we also know that there may be more in the first 200 pixels of a column than on average for that column.In addition to pinpointing roughly where the traps are, we can also do a similarly rough reckoning of where there may be more or fewer low-electron-grabbing traps than high-electron-grabbing traps. We can do this by post-flashing the CI images. If we take a variety of CI images with increasing levels of post-flash, we can take more and more of the low-traps off the table by looking at how the CI pixel gains and the trails lose with increasing post-flash level, we can also get a rough estimate of which traps are where.The observing plan is to take CI images with an array of background values {either from the post-flash on low or medium current}: 0, 1, 2, 4, 6, 8, 10, 12, 15, 20, 25, 37, 45, 52, 60, 67, 75, 82, 90, 105, 120, 135, 150, 175, 200, 250, 300, 500, 750, 1000, 2000, 3500, 5000, 10000, 15000, 20000, and 28000 electrons. This amounts to 39 internal exposures.The hope would be to take them over the period of a couple weeks and also take some long-short dark pairs over roughly the same timeframe so that we can re-pin the CTE model one last time before we release it into the pipeline. We could also try to repeat the external CTE-validation images with the post-flash variation, so that we can make an additional demonstration of the efficacy of the new correction.

  4. Modeling of Acoustic Pressure Waves in Level-Dependent Earplugs

    DTIC Science & Technology

    2008-09-01

    18 Figure 16. Comparison of experimental and predicted pressure response; M4 rifle at 1 m. ........19...range). The impulse events were created using an M4 rifle , a shortened variant of the M16A2. Figure 2 shows a typical test setup. The earplugs were...pressure levels at the head were created by firing the M4 rifle at varying distances from the manikin. Distances of 0.25, 0.5, 1, 2, 4, 8, 16, 32, and 64

  5. Doping level dependent space charge limited conduction in polyaniline nanoparticles

    NASA Astrophysics Data System (ADS)

    Nath, Chandrani; Kumar, A.

    2012-11-01

    Spherical shaped polyaniline nanoparticles of average diameter ˜4 nm were doped with different concentration of hydrochloric acid. The x-ray diffraction studies reveal an increase in crystallinity with doping. Temperature dependent current-voltage measurements on the different nanoparticle samples indicate the prevalence of bulk-controlled space charge limited conduction (SCLC) mechanism in the high voltage (>1 V) region while the ohmic conduction dominates at the lower voltage (<1 V) region. With increasing doping the nature of SCLC changes from trap-free SCLC to Child-Langmuir type SCLC via exponential trap-limited SCLC. Moreover, the field and temperature dependence of mobility exhibits the universal Poole-Frenkel behavior. The energetic disorder parameter, spatial disorder parameter, inter-site distance, and localization length have been extracted employing the uncorrelated and the correlated Gaussian disorder model.

  6. Meat nitrosamine contamination level depending on animal breeding factors.

    PubMed

    Rywotycki, Ryszard

    2003-09-01

    The aim of the work was to answer the question how the species, breeding factors and season of the year affect nitrosamine contents in raw meat. The concentrations were assessed in raw pork from gilts, sows, hogs and boars, in beef from heifers, cows, bullocks and bulls, in veal and in horse, ram and goat meat. The studies were conducted in spring, summer, autumn and in winter. Meat contents of nitrosamines (dimethylonitrosamine-DMNA and diethylonitrosamine-DENA) were assessed by Pancholy's method adapted to nitrosamine determination in meat and meat products by Scanlan and Ryes. The levels of DMNA and DENA were determined using a Varian 3400 gas chromatograph coupled to a mass spectrometer (Finnigan MAT ITD. 800). The volatiles were identified by comparing their mass spectra with standards and by comparison of retention times with standards. Quantitative and qualitative analysis was conducted by comparison with N-nitrosamine standard solution chromatograms. The highest nitrosamine (DMNA and DENA) concentrations were found in pork and beef, smaller in horseflesh and the lowest in ram and goat meat and in veal.

  7. Quantitative Proteomic Analysis Reveals Molecular Adaptations in the Hippocampal Synaptic Active Zone of Chronic Mild Stress-Unsusceptible Rats

    PubMed Central

    Zhou, Jian; Liu, Zhao; Yu, Jia; Han, Xin; Fan, Songhua; Shao, Weihua; Chen, Jianjun; Qiao, Rui

    2016-01-01

    Background: While stressful events are recognized as an important cause of major depressive disorder, some individuals exposed to life stressors maintain normal psychological functioning. The molecular mechanism(s) underlying this phenomenon remain unclear. Abnormal transmission and plasticity of hippocampal synapses have been implied to play a key role in the pathoetiology of major depressive disorder. Methods: A chronic mild stress protocol was applied to separate susceptible and unsusceptible rat subpopulations. Proteomic analysis using an isobaric tag for relative and absolute quantitation coupled with tandem mass spectrometry was performed to identify differential proteins in enriched hippocampal synaptic junction preparations. Results: A total of 4318 proteins were quantified, and 89 membrane proteins were present in differential amounts. Of these, SynaptomeDB identified 81 (91%) having a synapse-specific localization. The unbiased profiles identified several candidate proteins within the synaptic junction that may be associated with stress vulnerability or insusceptibility. Subsequent functional categorization revealed that protein systems particularly involved in membrane trafficking at the synaptic active zone exhibited a positive strain as potential molecular adaptations in the unsusceptible rats. Moreover, through STRING and immunoblotting analysis, membrane-associated GTP-bound Rab3a and Munc18-1 appear to coregulate syntaxin-1/SNAP25/VAMP2 assembly at the hippocampal presynaptic active zone of unsusceptible rats, facilitating SNARE-mediated membrane fusion and neurotransmitter release, and may be part of a stress-protection mechanism in actively maintaining an emotional homeostasis. Conclusions: The present results support the concept that there is a range of potential protein adaptations in the hippocampal synaptic active zone of unsusceptible rats, revealing new investigative targets that may contribute to a better understanding of stress

  8. The activity-regulated cytoskeletal-associated protein (Arc/Arg3.1) is required for memory consolidation of pavlovian fear conditioning in the lateral amygdala.

    PubMed

    Ploski, Jonathan E; Pierre, Vicki J; Smucny, Jason; Park, Kevin; Monsey, Melissa S; Overeem, Kathie A; Schafe, Glenn E

    2008-11-19

    The activity-regulated cytoskeletal-associated protein (Arc/Arg3.1) is an immediate early gene that has been widely implicated in hippocampal-dependent learning and memory and is believed to play an integral role in synapse-specific plasticity. Here, we examined the role of Arc/Arg3.1 in amygdala-dependent Pavlovian fear conditioning. We first examined the regulation of Arc/Arg3.1 mRNA and protein after fear conditioning and LTP-inducing stimulation of thalamic inputs to the lateral amygdala (LA). Quantitative real-time PCR, in situ hybridization, Western blotting and immunohistochemistry revealed a significant upregulation of Arc/Arg3.1 mRNA and protein in the LA relative to controls. In behavioral experiments, intra-LA infusion of an Arc/Arg3.1 antisense oligodeoxynucleotide (ODN) was observed to be anatomically restricted to the LA, taken up by LA cells, and to promote significant knockdown of Arc/Arg3.1 protein. Rats given intra-LA infusions of multiple doses of the Arc/Arg3.1 ODN showed an impairment of LTM (tested approximately 24 later), but no deficit in STM (tested 3 h later) relative to controls infused with scrambled ODN. Finally, to determine whether upregulation of Arc/Arg3.1 occurs downstream of ERK/MAPK activation, we examined Arc/Arg3.1 expression in rats given intra-LA infusion of the MEK inhibitor U0126. Relative to vehicle controls, infusion of U0126 impaired training-induced increases in Arc/Arg3.1 expression. These findings suggest that Arc/Arg3.1 expression in the amygdala is required for fear memory consolidation, and further suggest that Arc/Arg3.1 regulation in the LA is downstream of the ERK/MAPK signaling pathway.

  9. Enrichment of mGluR7a in the presynaptic active zones of GABAergic and non-GABAergic terminals on interneurons in the rat somatosensory cortex.

    PubMed

    Dalezios, Yannis; Luján, Rafael; Shigemoto, Ryuichi; Roberts, J David B; Somogyi, Peter

    2002-09-01

    The release of glutamate and GABA is modulated by presynaptic metabotropic glutamate receptors (mGluRs). We used immunocytochemical methods to define the location of the group III receptor mGluR7a in glutamatergic and GABAergic terminals innervating GABAergic interneurons and pyramidal cells. Immunoreactivity for mGluR7a was localized in the presynaptic active zone of both identified GABAergic and presumed glutamatergic terminals. Terminals innervating dendritic spines showed a variable level of receptor immunoreactivity, ranging from immunonegative to strongly immunopositive. The frequency of strongly mGluR7a positive terminals innervating the soma and dendrites of mGluR1 alpha/somatostatin-expressing interneurons was very high relative to other neurons. On dendrites that received mGluR7a-enriched glutamatergic innervation, at least 80% of GABAergic terminals were immunopositive for mGluR7a. On such dendrites virtually all (95%) vasoactive intestinal polypeptide (VIP) positive (GABAergic) terminals were enriched in mGluR7a. The targets of VIP/mGluR7a-expressing terminals were mainly (88%) mGluR1 alpha-expressing interneurons, which were mostly somatostatin immunopositive. Parvalbumin positive terminals were immunonegative for mGluR7a. Some parvalbumin immunoreactive dendrites received strongly mGluR7a positive terminals. The subcellular location, as well as the cell type and synapse-specific distribution of mGluR7a in isocortical neuronal circuits, is homologous to its distribution in the hippocampus. The specific location of mGluR7a in the presynaptic active zone of both glutamatergic and GABAergic synapses may be related to the proximity of calcium channels and the vesicle fusion machinery. The enrichment of mGluR7a in the main GABAergic, as well as in the glutamatergic, innervation of mGluR1 alpha/somatostatin-expressing interneurons suggests that their activation is under unique regulation by extracellular glutamate.

  10. Active-R filter

    DOEpatents

    Soderstrand, Michael A.

    1976-01-01

    An operational amplifier-type active filter in which the only capacitor in the circuit is the compensating capacitance of the operational amplifiers, the various feedback and coupling elements being essentially solely resistive.

  11. Level-Dependent Nonlinear Hearing Protector Model in the Auditory Hazard Assessment Algorithm for Humans

    DTIC Science & Technology

    2015-04-01

    2013) demonstrate the ability of the 3-piston model to describe the performance of liner hearing protectors. Although the 3- piston model does not... cylinder . This earplug uses a dual orifice design; the black-plastic piece is a hollow cylinder , with an orifice in each end. Sound enters the earplug...through the hole seen on the right side of the wider portion of the white cylinder . A yellow earpiece (as shown in Fig. 6) fits over the end of the

  12. DEPEND: A simulation-based environment for system level dependability analysis

    NASA Technical Reports Server (NTRS)

    Goswami, Kumar; Iyer, Ravishankar K.

    1992-01-01

    The design and evaluation of highly reliable computer systems is a complex issue. Designers mostly develop such systems based on prior knowledge and experience and occasionally from analytical evaluations of simplified designs. A simulation-based environment called DEPEND which is especially geared for the design and evaluation of fault-tolerant architectures is presented. DEPEND is unique in that it exploits the properties of object-oriented programming to provide a flexible framework with which a user can rapidly model and evaluate various fault-tolerant systems. The key features of the DEPEND environment are described, and its capabilities are illustrated with a detailed analysis of a real design. In particular, DEPEND is used to simulate the Unix based Tandem Integrity fault-tolerance and evaluate how well it handles near-coincident errors caused by correlated and latent faults. Issues such as memory scrubbing, re-integration policies, and workload dependent repair times which affect how the system handles near-coincident errors are also evaluated. Issues such as the method used by DEPEND to simulate error latency and the time acceleration technique that provides enormous simulation speed up are also discussed. Unlike any other simulation-based dependability studies, the use of these approaches and the accuracy of the simulation model are validated by comparing the results of the simulations, with measurements obtained from fault injection experiments conducted on a production Tandem Integrity machine.

  13. Visual extinction of similar and dissimilar stimuli: Evidence for level-dependent attentional competition.

    PubMed

    Ptak, Radek; Schnider, Armin

    2005-02-01

    Repetition blindness (RB) is the failure to report a visual stimulus presented shortly after a first occurrence of the same stimulus (Kanwisher, 1987). A similar phenomenon is that visual extinction, the failure to identify a contralesional stimulus presented simultaneously with an ipsilesional stimulus, increases with increasing similarity between the contralesional and ipsilesional stimulus (Baylis, Driver, & Rafal, 1993). We report a patient who, after a right parietal stroke, presented increased extinction for letters in repeated (e.g., A + A) than in unrepeated (e.g., T + U) displays. Increased extinction due to RB was observed in all experimental conditions probing item identification and varied between 5.4% and 40.6% across conditions. RB was unaffected by temporal modulation of the display, but was significantly reduced when stimuli grouped by a surrounding contour. Identification of contralesional repeated and unrepeated letters could be enhanced by auditory cues presented prior to the visual display. These results suggest that perceptual processing of extinguished stimuli that are similar to the stimulus presented on the preserved side is relatively unimpaired, but that the patient fails to ascribe to the stimulus a separate identity, supporting the distinction between type recognition and token individuation (Kanwisher, 1987). The extinction patterns for similar and dissimilar stimuli indicate that competition for attentional selection does not only occur at low (perceptual) levels, but also at higher processing levels, suggesting the presence of attentional competition on different levels of analysis.

  14. Hydration level dependence of the microscopic dynamics of water adsorbed in ultramicroporous carbon

    DOE PAGES

    Mamontov, Eugene; Yue, Yanfeng; Bahadur, Jitendra; ...

    2016-10-20

    Even when not functionalized intentionally, most carbon materials are not hydrophobic and readily adsorb water molecules from atmospheric water vapor. We have equilibrated an ultramicroporous carbon at several levels of relative humidity, thereby attaining various hydration levels. The water molecules were adsorbed on the pore walls (but did not fill completely the pore volume) and thus could be better described as hydration, or surface, rather than confined, water. We used quasielastic neutron scattering to perform a detailed investigation of the dependence of microscopic dynamics of these adsorbed water species on the hydration level and temperature. The behavior of hydration watermore » in ultramicroporous carbon clearly demonstrates the same universal traits that characterize surface (hydration) water in other materials that are surface-hydrated. In addition, unless special treatment is intentionally applied to ultramicroporous carbon, the species filling its pores in various applications, ranging from hydrogen molecules to electrolytes, likely find themselves in contact with non-freezing water molecules characterized by rich microscopic dynamics.« less

  15. Water level-dependent morphological plasticity in Sagittaria montevidensis Cham. and Schl. (Alismataceae).

    PubMed

    Demetrio, G R; Barbosa, M E A; Coelho, F F

    2014-08-01

    Aquatic plants are able to alter their morphology in response to environmental condition variation, such as water level fluctuations. The aim of this study was to evaluate the effect of water level on Sagittaria montevidensis morphology through measures of vegetative structures formed in drought and flood periods. We hypothesised that the plant height and the biomass of S. montevidensis leaves will increase during flood periods, while the biomass and diameter of petioles, and the basal plant area will increase during dry periods. We sampled a total amount of 270 individuals in nine sediment banks per visit, totalling 1080 plants. In order to compare plant morphology between dry and flood periods, we measured the water level in each bank and took the following variables for each plant: diameter, height and diameter of the biggest petiole. In order to compare biomass allocation between dry and flood periods, we sampled a total amount of 90 individuals in nine sediment banks per visit, totalling 360 plants. Plants were dried and weighed in the laboratory. All measured morphologic traits, as well as the biomass of leaf blades and petioles, were higher during flood periods, indicating that water level highly influences the morphology of S. montevidensis individuals. Our results suggest that these morphological responses allow survival and maintenance of S. montevidensis populations under environmental stress. These results can be linked to the invasive potential of S. montevidensis and sheds light on basic management practices that may be applied in the future.

  16. Hydration level dependence of the microscopic dynamics of water adsorbed in ultramicroporous carbon

    SciTech Connect

    Mamontov, Eugene; Yue, Yanfeng; Bahadur, Jitendra; Guo, Junjie; Contescu, Cristian I.; Gallego, Nidia C.; Melnichenko, Yuri B.

    2016-10-20

    Even when not functionalized intentionally, most carbon materials are not hydrophobic and readily adsorb water molecules from atmospheric water vapor. We have equilibrated an ultramicroporous carbon at several levels of relative humidity, thereby attaining various hydration levels. The water molecules were adsorbed on the pore walls (but did not fill completely the pore volume) and thus could be better described as hydration, or surface, rather than confined, water. We used quasielastic neutron scattering to perform a detailed investigation of the dependence of microscopic dynamics of these adsorbed water species on the hydration level and temperature. The behavior of hydration water in ultramicroporous carbon clearly demonstrates the same universal traits that characterize surface (hydration) water in other materials that are surface-hydrated. In addition, unless special treatment is intentionally applied to ultramicroporous carbon, the species filling its pores in various applications, ranging from hydrogen molecules to electrolytes, likely find themselves in contact with non-freezing water molecules characterized by rich microscopic dynamics.

  17. Fermi level dependent native defect formation: Consequences for metal-semiconductor and semiconductor-semiconductor interfaces

    SciTech Connect

    Walukiewicz, W.

    1988-02-01

    The amphoteric native defect model of the Schottky barrier formation is used to analyze the Fermi level pinning at metal/semiconductor interfaces for submonolayer metal coverages. It is assumed that the energy required for defect generation is released in the process of surface back-relaxation. Model calculations for metal/GaAs interfaces show a weak dependence of the Fermi level pinning on the thickness of metal deposited at room temperature. This weak dependence indicates a strong dependence of the defect formation energy on the Fermi level, a unique feature of amphoteric native defects. This result is in very good agreement with experimental data. It is shown that a very distinct asymmetry in the Fermi level pinning on p- and n-type GaAs observed at liquid nitrogen temperatures can be understood in terms of much different recombination rates for amphoteric native defects in those two types of materials. Also, it is demonstrated that the Fermi level stabilization energy, a central concept of the amphoteric defect system, plays a fundamental role in other phenomena in semiconductors such as semiconductor/semiconductor heterointerface intermixing and saturation of free carrier concentration. 33 refs., 6 figs.

  18. Level dependence in behavioral measurements of auditory-filter phase characteristics.

    PubMed

    Shen, Yi; Lentz, Jennifer J

    2009-11-01

    Two masking experiments were conducted to behaviorally estimate auditory-filter phase curvatures at different stimulus levels. Maskers were harmonic complexes consisting of equal-amplitude tones and phase spectra with varied curvatures. In Experiment 1, sinusoidal signal thresholds were measured at 2 and 4 kHz at fixed masker levels ranging from 50 to 90 dB sound pressure level (SPL). In Experiment 2, the masker level that just masked a sinusoidal signal at 2 and 4 kHz was measured at fixed signal levels of 25, 38, and 50 dB SPL. For both experiments, the estimated phase curvature approached zero (became less negative) with increasing stimulus level. This shift could suggest that the off-frequency phase characteristic of the auditory filter has an increasingly greater role on the estimated auditory-filter phase curvature at higher stimulus levels. This explanation is supported through the use of psychophysical modeling.

  19. Trophic-level dependent effects on CO2 emissions from experimental stream ecosystems.

    PubMed

    Atwood, Trisha B; Hammill, Edd; Richardson, John S

    2014-11-01

    Concern over accelerating rates of species invasions and losses have initiated investigations into how local and global changes to predator abundance mediate trophic cascades that influence CO2 fluxes of aquatic ecosystems. However, to date, no studies have investigated how species additions or losses at other consumer trophic levels influence the CO2 flux of aquatic ecosystems. In this study, we added a large predatory stonefly, detritivorous stonefly, or grazer tadpole to experimental stream food webs and over a 70-day period quantified their effects on community composition, leaf litter decomposition, chlorophyll-a concentrations, and stream CO2 emissions. In general, streams where the large grazer or large detritivore were added showed no change in total invertebrate biomass, leaf litter loss, chlorophyll-a concentrations, or stream CO2 emissions compared with controls; although we did observe a spike in CO2 emissions in the large grazer treatment following a substantial reduction in chlorophyll-a concentrations on day 28. However, the large grazer and large detritivore altered the community composition of streams by reducing the densities of other grazer and detritivore taxa, respectively, compared with controls. Conversely, the addition of the large predator created trophic cascades that reduced total invertebrate biomass and increased primary producer biomass. The cascading effects of the predator additions on the food web ultimately led to decreased CO2 emissions from stream channels by up to 95%. Our results suggest that stream ecosystem processes were more influenced by changes in large predator abundance than large grazer or detritivore abundance, because of a lack of functionally similar large predators. Our study demonstrates that the presence/absence of species with unique functional roles may have consequences for the exchange of CO2 between the ecosystem and the atmosphere.

  20. Optimal dynamic pricing and replenishment policy for perishable items with inventory-level-dependent demand

    NASA Astrophysics Data System (ADS)

    Lu, Lihao; Zhang, Jianxiong; Tang, Wansheng

    2016-04-01

    An inventory system for perishable items with limited replenishment capacity is introduced in this paper. The demand rate depends on the stock quantity displayed in the store as well as the sales price. With the goal to realise profit maximisation, an optimisation problem is addressed to seek for the optimal joint dynamic pricing and replenishment policy which is obtained by solving the optimisation problem with Pontryagin's maximum principle. A joint mixed policy, in which the sales price is a static decision variable and the replenishment rate remains to be a dynamic decision variable, is presented to compare with the joint dynamic policy. Numerical results demonstrate the advantages of the joint dynamic one, and further show the effects of different system parameters on the optimal joint dynamic policy and the maximal total profit.

  1. Get Active

    MedlinePlus

    ... Basics: Health Benefits What are the benefits of physical activity? Physical activity increases your chances of living longer. ... pain Help you feel better about yourself Is physical activity for everyone? Yes! Physical activity is good for ...

  2. Individual Variability in Brain Activity: A Nuisance or an Opportunity?

    PubMed

    Van Horn, John Darrell; Grafton, Scott T; Miller, Michael B

    2008-12-01

    Functional imaging research has been heavily influenced by results based on population-level inference. However, group average results may belie the unique patterns of activity present in the individual that ordinarily are considered random noise. Recent advances in the evolution of MRI hardware have led to significant improvements in the stability and reproducibility of blood oxygen level dependent (BOLD) measurements. These enhancements provide a unique opportunity for closer examination of individual patterns of brain activity. Three objectives can be accomplished by considering brain scans at the individual level; (1) Mapping functional anatomy at a fine grained analysis; (2) Determining if an individual scan is normative with respect to a reference population; and (3) Understanding the sources of intersubject variability in brain activity. In this review, we detail these objectives, briefly discuss their histories and present recent trends in the analyses of individual variability. Finally, we emphasize the unique opportunities and challenges for understanding individual differences through international collaboration among Pacific Rim investigators.

  3. Low molecular weight heparin restores antithrombin III activity from hyperglycemia induced alterations.

    PubMed

    Ceriello, A; Marchi, E; Palazzni, E; Quatraro, A; Giugliano, D

    1990-01-01

    Alteration of antithrombin III (ATIII) activity, glycemia level dependent, exists in diabetes mellitus. In this study the ability of a low molecular weight heparin (LMWH) (Fluxum, Alfa-Wassermann S.p.A., Bologna, Italy), as well as unfractioned héparin, to preserve ATIII activity from glucose-induced alterations, both in vitro and in vivo, is reported. The subcutaneous and intravenous LMWH and heparin administration increases basal depressed ATIII activity in diabetic patients. Heparin shows an equivalent effect on both anti-IIa and anti-Xa activity of ATIII, while LMWH is more effective in preserving the anti-Xa activity. Similarity, heparin preserves ATIII activity from hyperglycemia-induced alterations, during hyperglycemic clamp, and LMWH infusion is able to preserve a significant amount of anti-Xa activity from glucose-induced alterations. Since diabetic patients show a high incidence of thrombotic accidents, LMWH appears to be a promising innovation for the prevention of diabetic thrombophylia.

  4. Spatial heterogeneity analysis of brain activation in fMRI

    PubMed Central

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

    2014-01-01

    In many brain diseases it can be qualitatively observed that spatial patterns in blood oxygenation level dependent (BOLD) activation maps appear more (diffusively) distributed than in healthy controls. However, measures that can quantitatively characterize this spatial distributiveness in individual subjects are lacking. In this study, we propose a number of spatial heterogeneity measures to characterize brain activation maps. The proposed methods focus on different aspects of heterogeneity, including the shape (compactness), complexity in the distribution of activated regions (fractal dimension and co-occurrence matrix), and gappiness between activated regions (lacunarity). To this end, functional MRI derived activation maps of a language and a motor task were obtained in language impaired children with (Rolandic) epilepsy and compared to age-matched healthy controls. Group analysis of the activation maps revealed no significant differences between patients and controls for both tasks. However, for the language task the activation maps in patients appeared more heterogeneous than in controls. Lacunarity was the best measure to discriminate activation patterns of patients from controls (sensitivity 74%, specificity 70%) and illustrates the increased irregularity of gaps between activated regions in patients. The combination of heterogeneity measures and a support vector machine approach yielded further increase in sensitivity and specificity to 78% and 80%, respectively. This illustrates that activation distributions in impaired brains can be complex and more heterogeneous than in normal brains and cannot be captured fully by a single quantity. In conclusion, heterogeneity analysis has potential to robustly characterize the increased distributiveness of brain activation in individual patients. PMID:25161893

  5. Spatial heterogeneity analysis of brain activation in fMRI.

    PubMed

    Gupta, Lalit; Besseling, René M H; Overvliet, Geke M; Hofman, Paul A M; de Louw, Anton; Vaessen, Maarten J; Aldenkamp, Albert P; Ulman, Shrutin; Jansen, Jacobus F A; Backes, Walter H

    2014-01-01

    In many brain diseases it can be qualitatively observed that spatial patterns in blood oxygenation level dependent (BOLD) activation maps appear more (diffusively) distributed than in healthy controls. However, measures that can quantitatively characterize this spatial distributiveness in individual subjects are lacking. In this study, we propose a number of spatial heterogeneity measures to characterize brain activation maps. The proposed methods focus on different aspects of heterogeneity, including the shape (compactness), complexity in the distribution of activated regions (fractal dimension and co-occurrence matrix), and gappiness between activated regions (lacunarity). To this end, functional MRI derived activation maps of a language and a motor task were obtained in language impaired children with (Rolandic) epilepsy and compared to age-matched healthy controls. Group analysis of the activation maps revealed no significant differences between patients and controls for both tasks. However, for the language task the activation maps in patients appeared more heterogeneous than in controls. Lacunarity was the best measure to discriminate activation patterns of patients from controls (sensitivity 74%, specificity 70%) and illustrates the increased irregularity of gaps between activated regions in patients. The combination of heterogeneity measures and a support vector machine approach yielded further increase in sensitivity and specificity to 78% and 80%, respectively. This illustrates that activation distributions in impaired brains can be complex and more heterogeneous than in normal brains and cannot be captured fully by a single quantity. In conclusion, heterogeneity analysis has potential to robustly characterize the increased distributiveness of brain activation in individual patients.

  6. Temporal Sequencing of Brain Activations During Naturally Occurring Thermoregulatory Events

    PubMed Central

    Diwadkar, Vaibhav A.; Murphy, Eric R.; Freedman, Robert R.

    2014-01-01

    Thermoregulatory events are associated with activity in the constituents of the spinothalamic tract. Whereas studies have assessed activity within constituents of this pathway, in vivo functional magnetic resonance imaging (fMRI) studies have not determined if neuronal activity in the constituents of the tract is temporally ordered. Ordered activity would be expected in naturally occurring thermal events, such as menopausal hot flashes (HFs), which occur in physiological sequence. The origins of HFs may lie in brainstem structures where neuronal activity may occur earlier than in interoceptive centers, such as the insula and the prefrontal cortex. To study such time ordering, we conducted blood oxygen level-dependent-based fMRI in a group of postmenopausal women to measure neuronal activity in the brainstem, insula, and prefrontal cortex around the onset of an HF (detected using synchronously acquired skin conductance responses). Rise in brainstem activity occurred before the detectable onset of an HF. Activity in the insular and prefrontal trailed that in the brainstem, appearing following the onset of the HF. Additional activations associated with HF's were observed in the anterior cingulate cortex and the basal ganglia. Pre-HF brainstem responses may reflect the functional origins of internal thermoregulatory events. By comparison insular, prefrontal and striatal activity may be associated with the phenomenological correlates of HFs. PMID:23787950

  7. Activation detector

    DOEpatents

    Bell, Zane William [Oak Ridge, TN; Boatner, Lynn Allen [Oak Ridge, TN

    2009-12-08

    A method of detecting an activator, the method including impinging with an activator a receptor material lacking a photoluminescent material and generating a by-product of a radioactive decay due to the activator impinging the reeptor material. The method further including, generating light from the by-product via the Cherenkov effect and identifying a characteristic of the activator based on the light.

  8. Brain activation during facial emotion processing.

    PubMed

    Gur, Ruben C; Schroeder, Lee; Turner, Travis; McGrath, Claire; Chan, Robin M; Turetsky, Bruce I; Alsop, David; Maldjian, Joseph; Gur, Raquel E

    2002-07-01

    Functional neuroimaging studies have helped identify neural systems involved in cognitive processing and more recently have indicated limbic activation to emotional stimuli. Some functional magnetic resonance imaging (fMRI) studies have reported increased amygdala response during exposure to emotional stimuli while others have not shown such activation. The present study was designed to test the hypothesis that activation of the amygdala is related to the relevance of the emotional valence of stimuli. Healthy young participants (7 men, 7 women) were studied in a high-field (4 tesla) scanner using blood oxygenation-level dependent (BOLD) signal changes in a blocked "box car" design. They viewed facial displays of happiness, sadness, anger, fear, and disgust as well as neutral faces obtained from professional actors and actresses of diverse ethnicity and age. Their task alternated between emotion discrimination (indicating whether the emotion was positive or negative) and age discrimination (indicating whether the poser was older or younger than 30). Blocks contained the same proportion of emotional and neutral faces. Limbic response was greater during the emotion than during the age discrimination conditions. The response was most pronounced in the amygdala, but was also present in the hippocampus and circumscribed voxels in other limbic regions. These results support the central role of the amygdala in emotion processing, and indicate its sensitivity to the task relevance of the emotional display.

  9. Modelling of activation processes for GR-280 graphite at Ignalina NPP.

    PubMed

    Smaizys, Arturas; Narkunas, Ernestas; Poskas, Povilas

    2005-01-01

    Ignalina Nuclear Power Plant (INPP) operates two RBMK-1500 water-cooled graphite-moderated channel-type power reactors. The total mass of graphite in the cores of both units at INPP is about 3600 tons. Modelling of activation processes in the reactor's structural materials is necessary for decommissioning planning, because large amounts of activated structural materials (graphite, stainless steel, concrete, etc.) should be managed as radioactive waste. Knowledge of radiological characteristics and a radioactive inventory of irradiated materials are essential in planning of the decommissioning processes. The purpose of this work was to perform conservative neutron activation analysis for decommissioning purposes of INPP. ORIGEN computer code was used for the calculations. Activity levels were calculated for different nuclides present in the graphite and estimates were made how these activity levels depend on irradiation time, neutron flux value and other parameters. Obtained results were compared with the data available from other investigations for GR-280 graphite.

  10. Steady-state activation in somatosensory cortex after changes in stimulus rate during median nerve stimulation.

    PubMed

    Manganotti, Paolo; Formaggio, Emanuela; Storti, Silvia Francesca; Avesani, Mirko; Acler, Michele; Sala, Francesco; Magon, Stefano; Zoccatelli, Giada; Pizzini, Francesca; Alessandrini, Franco; Fiaschi, Antonio; Beltramello, Alberto

    2009-11-01

    Passive electrical stimulation activates various human somatosensory cortical systems including the contralateral primary somatosensory area (SI), bilateral secondary somatosensory area (SII) and bilateral insula. The effect of stimulation frequency on blood oxygenation level-dependent (BOLD) activity remains unclear. We acquired 3-T functional magnetic resonance imaging (fMRI) in eight healthy volunteers during electrical median nerve stimulation at frequencies of 1, 3 and 10 Hz. During stimulation BOLD signal changes showed activation in the contralateral SI, bilateral SII and bilateral insula. Results of fMRI analysis showed that these areas were progressively active with the increase of rate of stimulation. As a major finding, the contralateral SI showed an increase of peak of BOLD activation from 1 to 3 Hz but reached a plateau during 10-Hz stimulation. Our finding is of interest for basic research and for clinical applications in subjects unable to perform cognitive tasks in the fMRI scanner.

  11. Midbrain activation during Pavlovian conditioning and delusional symptoms in schizophrenia.

    PubMed

    Romaniuk, Liana; Honey, Garry D; King, Julia R L; Whalley, Heather C; McIntosh, Andrew M; Levita, Liat; Hughes, Mark; Johnstone, Eve C; Day, Mark; Lawrie, Stephen M; Hall, Jeremy

    2010-12-01

    Recent theories have suggested that the inappropriate activation of limbic motivational systems in response to neutral stimuli may underlie the development of delusions in schizophrenia. To investigate the activation of the amygdala, midbrain, and ventral striatum during an aversive pavlovian conditioning task in patients with schizophrenia and healthy control participants using functional magnetic resonance imaging. Cross-sectional case-control functional neuroimaging study. Academic medical center. Twenty patients with DSM-IV-diagnosed schizophrenia or schizoaffective disorder and 20 healthy control participants. Regional brain activation as assessed by functional magnetic resonance imaging blood oxygen level-dependent responses, and delusional symptom severity on the Positive and Negative Syndrome Scale. Patients with schizophrenia showed abnormal activation of the amygdala, midbrain, and ventral striatum during conditioning. Activation of the midbrain in response to neutral rather than aversive cues during conditioning was correlated with the severity of delusional symptoms in the patient group (corrected P = .04). Inappropriate activation of the midbrain in response to neutral stimuli during conditioning is associated with the severity of delusional symptoms in patients with schizophrenia.

  12. Faculty Activism

    ERIC Educational Resources Information Center

    Academe, 2005

    2005-01-01

    Blending scholarship and activism, whether domestic or international, takes some real work. Two scholar-activists reflect on why and how activism can be more than academic labor in this feature of the "Academe" journal. This feature includes the following brief reflections on political work, both local and global that demonstrates how on…

  13. Astronomy Activities.

    ERIC Educational Resources Information Center

    Greenstone, Sid

    This document consists of activities and references for teaching astronomy. The activities (which include objectives, list of materials needed, and procedures) focus on: observing the Big Dipper and locating the North Star; examining the Big Dipper's stars; making and using an astrolabe; examining retograde motion of Mars; measuring the Sun's…

  14. Astronomy Activities.

    ERIC Educational Resources Information Center

    Greenstone, Sid

    This document consists of activities and references for teaching astronomy. The activities (which include objectives, list of materials needed, and procedures) focus on: observing the Big Dipper and locating the North Star; examining the Big Dipper's stars; making and using an astrolabe; examining retograde motion of Mars; measuring the Sun's…

  15. Catalyst activator

    DOEpatents

    McAdon, Mark H.; Nickias, Peter N.; Marks, Tobin J.; Schwartz, David J.

    2001-01-01

    A catalyst activator particularly adapted for use in the activation of metal complexes of metals of Group 3-10 for polymerization of ethylenically unsaturated polymerizable monomers, especially olefins, comprising two Group 13 metal or metalloid atoms and a ligand structure including at least one bridging group connecting ligands on the two Group 13 metal or metalloid atoms.

  16. Outdoor Activities.

    ERIC Educational Resources Information Center

    Minneapolis Independent School District 275, Minn.

    Twenty-four activities suitable for outdoor use by elementary school children are outlined. Activities designed to make children aware of their environment include soil painting, burr collecting, insect and pond water collecting, studies of insect galls and field mice, succession studies, and a model of natural selection using dyed toothpicks. A…

  17. Active matter

    NASA Astrophysics Data System (ADS)

    Ramaswamy, Sriram

    2017-05-01

    The study of systems with sustained energy uptake and dissipation at the scale of the constituent particles is an area of central interest in nonequilibrium statistical physics. Identifying such systems as a distinct category—Active matter—unifies our understanding of autonomous collective movement in the living world and in some surprising inanimate imitations. In this article I present the active matter framework, briefly recall some early work, review our recent results on single-particle and collective behaviour, including experiments on active granular monolayers, and discuss new directions for the future.

  18. Activated Charcoal

    MedlinePlus

    ... is used to treat poisonings, reduce intestinal gas (flatulence), lower cholesterol levels, prevent hangover, and treat bile ... lower cholesterol levels in the blood. Decreasing gas (flatulence). Some studies show that activated charcoal is effective ...

  19. Activity Theory.

    ERIC Educational Resources Information Center

    Koschmann, Timothy; Roschelle, Jeremy; Nardi, Bonnie A.

    1998-01-01

    Includes three articles that discuss activity theory, based on "Context and Consciousness." Topics include human-computer interaction; computer interfaces; hierarchical structuring; mediation; contradictions and development; failure analysis; and designing educational technology. (LRW)

  20. Activation analysis

    SciTech Connect

    Alfassi, Z.B. . Dept. of Nuclear Engineering)

    1990-01-01

    This volume contains 16 chapters on the application of activation analysis in the fields of life sciences, biological materials, coal and its effluents, environmental samples, archaeology, material science, and forensics. Each chapter is processed separately for the data base.

  1. Activity Theory.

    ERIC Educational Resources Information Center

    Koschmann, Timothy; Roschelle, Jeremy; Nardi, Bonnie A.

    1998-01-01

    Includes three articles that discuss activity theory, based on "Context and Consciousness." Topics include human-computer interaction; computer interfaces; hierarchical structuring; mediation; contradictions and development; failure analysis; and designing educational technology. (LRW)

  2. Mapping brain region activity during chewing: a functional magnetic resonance imaging study.

    PubMed

    Onozuka, M; Fujita, M; Watanabe, K; Hirano, Y; Niwa, M; Nishiyama, K; Saito, S

    2002-11-01

    Mastication has been suggested to increase neuronal activities in various regions of the human brain. However, because of technical difficulties, the fine anatomical and physiological regions linked to mastication have not been fully elucidated. Using functional magnetic resonance imaging during cycles of rhythmic gum-chewing and no chewing, we therefore examined the interaction between chewing and brain regional activity in 17 subjects (aged 20-31 years). In all subjects, chewing resulted in a bilateral increase in blood oxygenation level-dependent (BOLD) signals in the sensorimotor cortex, supplementary motor area, insula, thalamus, and cerebellum. In addition, in the first three regions, chewing of moderately hard gum produced stronger BOLD signals than the chewing of hard gum. However, the signal was higher in the cerebellum and not significant in the thalamus, respectively. These results suggest that chewing causes regional increases in brain neuronal activities which are related to biting force.

  3. Physiological basis and image processing in functional magnetic resonance imaging: Neuronal and motor activity in brain

    PubMed Central

    Sharma, Rakesh; Sharma, Avdhesh

    2004-01-01

    Functional magnetic resonance imaging (fMRI) is recently developing as imaging modality used for mapping hemodynamics of neuronal and motor event related tissue blood oxygen level dependence (BOLD) in terms of brain activation. Image processing is performed by segmentation and registration methods. Segmentation algorithms provide brain surface-based analysis, automated anatomical labeling of cortical fields in magnetic resonance data sets based on oxygen metabolic state. Registration algorithms provide geometric features using two or more imaging modalities to assure clinically useful neuronal and motor information of brain activation. This review article summarizes the physiological basis of fMRI signal, its origin, contrast enhancement, physical factors, anatomical labeling by segmentation, registration approaches with examples of visual and motor activity in brain. Latest developments are reviewed for clinical applications of fMRI along with other different neurophysiological and imaging modalities. PMID:15125779

  4. Plant metacaspase activation and activity.

    PubMed

    Minina, Elena A; Stael, Simon; Van Breusegem, Frank; Bozhkov, Peter V

    2014-01-01

    Metacaspases are essential for cell death regulation in plants. Further understanding of biochemistry of metacaspases and their molecular function in plant biology requires a set of robust methods for detection of metacaspase activation and quantitative analysis of corresponding proteolytic activity. Here we describe methods for purification of recombinant metacaspases, measurement of enzymatic activity of recombinant and endogenous metacaspases in vitro and in cell lysates, respectively, and finally detection of metacaspase activation in vivo. Additionally, an in vitro metacaspase protein substrate cleavage assay based on the cell-free production of substrate protein followed by proteolysis with recombinant metacaspase is presented. These methods have been originally developed for type II metacaspases from Arabidopsis and Norway spruce (Picea abies), but they can be used as templates for type I metacaspases, as well as for type II metacaspases from other species.

  5. Active colloids

    NASA Astrophysics Data System (ADS)

    Aranson, Igor S.

    2013-01-01

    A colloidal suspension is a heterogeneous fluid containing solid microscopic particles. Colloids play an important role in our everyday life, from food and pharmaceutical industries to medicine and nanotechnology. It is useful to distinguish two major classes of colloidal suspensions: equilibrium and active, i.e., maintained out of thermodynamic equilibrium by external electric or magnetic fields, light, chemical reactions, or hydrodynamic shear flow. While the properties of equilibrium colloidal suspensions are fairly well understood, active colloids pose a formidable challenge, and the research is in its early exploratory stage. One of the most remarkable properties of active colloids is the possibility of dynamic self-assembly, a natural tendency of simple building blocks to organize into complex functional architectures. Examples range from tunable, self-healing colloidal crystals and membranes to self-assembled microswimmers and robots. Active colloidal suspensions may exhibit material properties not present in their equilibrium counterparts, e.g., reduced viscosity and enhanced self-diffusivity, etc. This study surveys the most recent developments in the physics of active colloids, both in synthetic and living systems, with the aim of elucidation of the fundamental physical mechanisms governing self-assembly and collective behavior.

  6. Active dependency.

    PubMed

    Bornstein, R F

    1995-02-01

    Although dependency has long been associated with passivity, weakness, and submissiveness, a review of the empirical literature reveals that, in certain situations and settings, dependent persons actually exhibit a variety of active, assertive behaviors. In this article, I: a) trace the historical roots of the dependency-passivity link; b) review empirical studies from developmental, social, and clinical psychology which indicate that, in certain circumstances, dependency is associated with active, assertive behavior on the part of the dependent person; c) offer an alternative conceptual model of dependency that accounts for the entire range of behaviors-both passive and active-that are exhibited by the dependent person; and d) discuss the diagnostic and therapeutic implications of this alternative conceptual model of dependency.

  7. Active Cytokinins

    PubMed Central

    Mornet, René; Theiler, Jane B.; Leonard, Nelson J.; Schmitz, Ruth Y.; Moore, F. Hardy; Skoog, Folke

    1979-01-01

    Four series of azidopurines have been synthesized and tested for cytokinin activity in the tobacco callus bioassay: 2- and 8-azido-N6-benzyladenines, -N6-(Δ2-isopentenyl)adenines, and -zeatins, and N6-(2- and 4-azidobenzyl)adenines. The compounds having 2-azido substitution on the adenine ring are as active as the corresponding parent compounds, while those with 8-azido substitution are about 10 or more times as active. The 8-azidozeatin, which is the most active cytokinin observed, exhibited higher than minimal detectable activity at 1.2 × 10−5 micromolar, the lowest concentration tested. The shape of the growth curve indicates that even a concentration as low as 5 × 10−6 micromolar would probably be effective. By comparison, the lowest active concentration ever reported for zeatin has been 5 × 10−5 micromolar, representing a sensitivity rarely attained. All of the azido compounds have been submitted to photolysis in aqueous ethanol, and the photoproducts have been detected and identified by low and high resolution mass spectrometry. They are rationalized as products of abstraction and insertion reactions of the intermediate nitrenes. The potential of the major released products as cytokinins was also assessed by bioassay. 2-Azido-N6-(Δ2-isopentenyl)adenine competed with [14C]kinetin for the cytokinin-binding protein isolated from wheat germ. When the azido compound was photolysed in the presence of this protein, its attachment effectively blocked the binding of [14C]kinetin. PMID:16661017

  8. Active microwaves

    NASA Technical Reports Server (NTRS)

    Evans, D.; Vidal-Madjar, D.

    1994-01-01

    Research on the use of active microwaves in remote sensing, presented during plenary and poster sessions, is summarized. The main highlights are: calibration techniques are well understood; innovative modeling approaches have been developed which increase active microwave applications (segmentation prior to model inversion, use of ERS-1 scatterometer, simulations); polarization angle and frequency diversity improves characterization of ice sheets, vegetation, and determination of soil moisture (X band sensor study); SAR (Synthetic Aperture Radar) interferometry potential is emerging; use of multiple sensors/extended spectral signatures is important (increase emphasis).

  9. Leaf Activities.

    ERIC Educational Resources Information Center

    Mingie, Walter

    Leaf activities can provide a means of using basic concepts of outdoor education to learn in elementary level subject areas. Equipment needed includes leaves, a clipboard with paper, and a pencil. A bag of leaves may be brought into the classroom if weather conditions or time do not permit going outdoors. Each student should pick a leaf, examine…

  10. Learning Activities.

    ERIC Educational Resources Information Center

    Tipton, Tom, Ed.

    1983-01-01

    Presents a flow chart for naming inorganic compounds. Although it is not necessary for students to memorize rules, preliminary skills needed before using the chart are outlined. Also presents an activity in which the mass of an imaginary atom is determined using lead shot, Petri dishes, and a platform balance. (JN)

  11. Activities: Spirolaterals.

    ERIC Educational Resources Information Center

    Brannan, Richard; McFadden, Scott

    1981-01-01

    A set of activities designed to help students discover properties about order-3 spirolaterals on square grid paper is presented. The materials are prepared on worksheets designed for easy duplication. The lessons can lead to investigations involving spirolaterals of many other orders and shapes. (MP)

  12. Activity report

    SciTech Connect

    Yu, S W

    2008-08-11

    This report is aimed to show the author's activities to support the LDRD. The title is 'Investigation of the Double-C Behavior in the Pu-Ga Time-Temperature-Transformation Diagram' The sections are: (1) Sample Holder Test; (2) Calculation of x-ray diffraction patterns; (3) Literature search and preparing publications; (4) Tasks Required for APS Experiments; and (5) Communications.

  13. Activated Sludge.

    ERIC Educational Resources Information Center

    Saunders, F. Michael

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. This review covers: (1) activated sludge process; (2) process control; (3) oxygen uptake and transfer; (4) phosphorus removal; (5) nitrification; (6) industrial wastewater; and (7) aerobic digestion. A list of 136 references is also presented. (HM)

  14. Classroom Activities.

    ERIC Educational Resources Information Center

    Stuart, Frances R.

    This pamphlet suggests activities that may be used in the elementary school classroom. Chapter I lists various short plays that children can easily perform which encourage their imagination. Chapter II details a few quiet classroom games such as "I Saw,""Corral the Wild Horse,""Who Has Gone from the Room," and "Six-Man-Football Checkers." A number…

  15. Activated Sludge.

    ERIC Educational Resources Information Center

    Saunders, F. Michael

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. This review covers: (1) activated sludge process; (2) process control; (3) oxygen uptake and transfer; (4) phosphorus removal; (5) nitrification; (6) industrial wastewater; and (7) aerobic digestion. A list of 136 references is also presented. (HM)

  16. Learning Activities.

    ERIC Educational Resources Information Center

    Tipton, Tom, Ed.

    1983-01-01

    Presents a flow chart for naming inorganic compounds. Although it is not necessary for students to memorize rules, preliminary skills needed before using the chart are outlined. Also presents an activity in which the mass of an imaginary atom is determined using lead shot, Petri dishes, and a platform balance. (JN)

  17. Sex differences in brain activation elicited by humor.

    PubMed

    Azim, Eiman; Mobbs, Dean; Jo, Booil; Menon, Vinod; Reiss, Allan L

    2005-11-08

    With recent investigation beginning to reveal the cortical and subcortical neuroanatomical correlates of humor appreciation, the present event-related functional MRI (fMRI) study was designed to elucidate sex-specific recruitment of these humor related networks. Twenty healthy subjects (10 females) underwent fMRI scanning while subjectively rating 70 verbal and nonverbal achromatic cartoons as funny or unfunny. Data were analyzed by comparing blood oxygenation-level-dependent signal activation during funny and unfunny stimuli. Males and females share an extensive humor-response strategy as indicated by recruitment of similar brain regions: both activate the temporal-occipital junction and temporal pole, structures implicated in semantic knowledge and juxtaposition, and the inferior frontal gyrus, likely to be involved in language processing. Females, however, activate the left prefrontal cortex more than males, suggesting a greater degree of executive processing and language-based decoding. Females also exhibit greater activation of mesolimbic regions, including the nucleus accumbens, implying greater reward network response and possibly less reward expectation. These results indicate sex-specific differences in neural response to humor with implications for sex-based disparities in the integration of cognition and emotion.

  18. Sex differences in brain activation elicited by humor

    PubMed Central

    Azim, Eiman; Mobbs, Dean; Jo, Booil; Menon, Vinod; Reiss, Allan L.

    2005-01-01

    With recent investigation beginning to reveal the cortical and subcortical neuroanatomical correlates of humor appreciation, the present event-related functional MRI (fMRI) study was designed to elucidate sex-specific recruitment of these humor related networks. Twenty healthy subjects (10 females) underwent fMRI scanning while subjectively rating 70 verbal and nonverbal achromatic cartoons as funny or unfunny. Data were analyzed by comparing blood oxygenation-level-dependent signal activation during funny and unfunny stimuli. Males and females share an extensive humor-response strategy as indicated by recruitment of similar brain regions: both activate the temporal-occipital junction and temporal pole, structures implicated in semantic knowledge and juxtaposition, and the inferior frontal gyrus, likely to be involved in language processing. Females, however, activate the left prefrontal cortex more than males, suggesting a greater degree of executive processing and language-based decoding. Females also exhibit greater activation of mesolimbic regions, including the nucleus accumbens, implying greater reward network response and possibly less reward expectation. These results indicate sex-specific differences in neural response to humor with implications for sex-based disparities in the integration of cognition and emotion. PMID:16275931

  19. Platelet Serotonin Transporter Function Predicts Default-Mode Network Activity

    PubMed Central

    Kasess, Christian H.; Meyer, Bernhard M.; Hofmaier, Tina; Diers, Kersten; Bartova, Lucie; Pail, Gerald; Huf, Wolfgang; Uzelac, Zeljko; Hartinger, Beate; Kalcher, Klaudius; Perkmann, Thomas; Haslacher, Helmuth; Meyer-Lindenberg, Andreas; Kasper, Siegfried; Freissmuth, Michael; Windischberger, Christian; Willeit, Matthäus; Lanzenberger, Rupert; Esterbauer, Harald; Brocke, Burkhard; Moser, Ewald; Sitte, Harald H.; Pezawas, Lukas

    2014-01-01

    Background The serotonin transporter (5-HTT) is abundantly expressed in humans by the serotonin transporter gene SLC6A4 and removes serotonin (5-HT) from extracellular space. A blood-brain relationship between platelet and synaptosomal 5-HT reuptake has been suggested, but it is unknown today, if platelet 5-HT uptake can predict neural activation of human brain networks that are known to be under serotonergic influence. Methods A functional magnetic resonance study was performed in 48 healthy subjects and maximal 5-HT uptake velocity (Vmax) was assessed in blood platelets. We used a mixed-effects multilevel analysis technique (MEMA) to test for linear relationships between whole-brain, blood-oxygen-level dependent (BOLD) activity and platelet Vmax. Results The present study demonstrates that increases in platelet Vmax significantly predict default-mode network (DMN) suppression in healthy subjects independent of genetic variation within SLC6A4. Furthermore, functional connectivity analyses indicate that platelet Vmax is related to global DMN activation and not intrinsic DMN connectivity. Conclusion This study provides evidence that platelet Vmax predicts global DMN activation changes in healthy subjects. Given previous reports on platelet-synaptosomal Vmax coupling, results further suggest an important role of neuronal 5-HT reuptake in DMN regulation. PMID:24667541

  20. Pentraxin 3 predicts complicated course of febrile neutropenia in haematological patients, but the decision level depends on the underlying malignancy.

    PubMed

    Juutilainen, Auni; Vänskä, Matti; Pulkki, Kari; Hämäläinen, Sari; Nousiainen, Tapio; Jantunen, Esa; Koivula, Irma

    2011-11-01

    This study aimed at assessing the cut-off levels for pentraxin 3 (PTX3) in predicting complications of neutropenic fever (bacteraemia, septic shock) in haematological patients. A prospective study during 2006-2009 was performed at haematology ward in Kuopio University Hospital. A patient was eligible for the study if having neutropenic fever after intensive therapy for acute myeloid leukaemia (AML) (n = 32) or non-Hodgkin lymphoma (NHL) (n = 35). Blood cultures were taken, and maximal PTX3 and C-reactive protein (CRP) were evaluated during d0 to d3 from the beginning of fever onset. The level of PTX3 was associated with both the underlying malignancy and the presence of complications, with highest level in NHL patients with complicated course of febrile neutropenia and lowest in AML patients with non-complicated course. The cut-off level of PTX3 to predict complications was ten-fold in patients with NHL (115 μg/L) in comparison with patients with AML (11.5 μg/L). In combined analysis based on separate cut-offs, PTX3 predicted complications of febrile neutropenia with sensitivity of 0.86, specificity of 0.83, positive predictive value of 0.57 and negative predictive value of 0.96.   PTX3 was superior to CRP in predicting complicated course of febrile neutropenia, but only when the effect of the underlying malignancy had been taken into account. © 2011 John Wiley & Sons A/S.

  1. Applications of blood-oxygen-level-dependent functional magnetic resonance imaging and diffusion tensor imaging in epilepsy.

    PubMed

    Chaudhary, Umair J; Duncan, John S

    2014-11-01

    The lifetime prevalence of epilepsy ranges from 2.7 to 12.4 per 1000 in Western countries. Around 30% of patients with epilepsy remain refractory to antiepileptic drugs and continue to have seizures. Noninvasive imaging techniques such as functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) have helped to better understand mechanisms of seizure generation and propagation, and to localize epileptic, eloquent, and cognitive networks. In this review, the clinical applications of fMRI and DTI are discussed, for mapping cognitive and epileptic networks and organization of white matter tracts in individuals with epilepsy.

  2. U.S. Marine Corps Level-Dependent Hearing Protector Assessment: Objective Measures of Hearing Protection Devices

    DTIC Science & Technology

    2014-01-01

    earplug (EB15) is an “active” device designed to use electronic limiters and compression to provide hearing of low-level ambient sounds while protecting...so designated by other authorized documents. Citation of manufacturer’s or trade names does not constitute an official endorsement or approval of...incorporation of a filter that allows the user to hear ambient sounds with minimal attenuation but protects against impulsive noises above about 105-dB

  3. An Analysis of Variance in Teacher Self-Efficacy Levels Dependent on Participation Time in Professional Learning Communities

    ERIC Educational Resources Information Center

    Marx, Megan D.

    2016-01-01

    The purpose of this study was to determine variance in mean levels of teacher self-efficacy (TSE) and its three factors--efficacy in student engagement (EIS), efficacy in instructional strategies (EIS), and efficacy in classroom management (ECM)--based on participation and time spent in professional learning communities (PLCs). In this…

  4. Visual perception from the perspective of a representational, non-reductionistic, level-dependent account of perception and conscious awareness.

    PubMed

    Overgaard, Morten; Mogensen, Jesper

    2014-05-05

    This article proposes a new model to interpret seemingly conflicting evidence concerning the correlation of consciousness and neural processes. Based on an analysis of research of blindsight and subliminal perception, the reorganization of elementary functions and consciousness framework suggests that mental representations consist of functions at several different levels of analysis, including truly localized perceptual elementary functions and perceptual algorithmic modules, which are interconnections of the elementary functions. We suggest that conscious content relates to the 'top level' of analysis in a 'situational algorithmic strategy' that reflects the general state of an individual. We argue that conscious experience is intrinsically related to representations that are available to guide behaviour. From this perspective, we find that blindsight and subliminal perception can be explained partly by too coarse-grained methodology, and partly by top-down enhancing of representations that normally would not be relevant to action.

  5. Visual perception from the perspective of a representational, non-reductionistic, level-dependent account of perception and conscious awareness

    PubMed Central

    Overgaard, Morten; Mogensen, Jesper

    2014-01-01

    This article proposes a new model to interpret seemingly conflicting evidence concerning the correlation of consciousness and neural processes. Based on an analysis of research of blindsight and subliminal perception, the reorganization of elementary functions and consciousness framework suggests that mental representations consist of functions at several different levels of analysis, including truly localized perceptual elementary functions and perceptual algorithmic modules, which are interconnections of the elementary functions. We suggest that conscious content relates to the ‘top level’ of analysis in a ‘situational algorithmic strategy’ that reflects the general state of an individual. We argue that conscious experience is intrinsically related to representations that are available to guide behaviour. From this perspective, we find that blindsight and subliminal perception can be explained partly by too coarse-grained methodology, and partly by top-down enhancing of representations that normally would not be relevant to action. PMID:24639581

  6. An Analysis of Variance in Teacher Self-Efficacy Levels Dependent on Participation Time in Professional Learning Communities

    ERIC Educational Resources Information Center

    Marx, Megan D.

    2016-01-01

    The purpose of this study was to determine variance in mean levels of teacher self-efficacy (TSE) and its three factors--efficacy in student engagement (EIS), efficacy in instructional strategies (EIS), and efficacy in classroom management (ECM)--based on participation and time spent in professional learning communities (PLCs). In this…

  7. An EPQ model for deteriorating items with inventory-level-dependent demand and permissible delay in payments

    NASA Astrophysics Data System (ADS)

    Min, Jie; Zhou, Yong-Wu; Liu, Gui-Qing; Wang, Sheng-Dong

    2012-06-01

    This article develops an inventory model for exponentially deteriorating items under conditions of permissible delay in payments. Unlike the existing related models, we assume that the items are replenished at a finite rate and the demand rate of the items is dependent on the current inventory level. The objective is to determine the optimal replenishment policies in order to maximise the system's average profit per unit of time. A simple method is shown for finding the optimal solution of the model based on the derived properties of the objective function. In addition, we deduce some previously published results as the special cases of the model. Finally, numerical examples are used to illustrate the proposed model. Some managerial insights are also inferred from the sensitive analysis of model parameters.

  8. Lithium's effect in forced-swim test is blood level dependent but not dependent on weight loss.

    PubMed

    Bersudsky, Yuly; Shaldubina, Alona; Belmaker, R H

    2007-02-01

    The effects of lithium in models of depression are often inconsistent. We aimed to replicate a regimen that induces robust antidepressant effects in the forced-swim test. Mice were treated with three different doses of lithium chloride (LiCl) 0.25, 0.4 or 0.5% in food and the forced-swim test or open field test was performed on day 15. We yoked control mice to food deprivation to test whether lithium-induced food deprivation could cause the lithium effects in the forced-swim test. Treatment with LiCl doses leading to blood levels of 1.3 and 1.4 mmol/l led to highly significant reduction in immobility time in the forced-swim test, but the dose leading to a blood level of 0.8 mmol/l was not different from controls in immobility time. Mice yoked to lithium-induced food deprivation showed no difference in the forced-swim test compared with controls. In conclusion these results suggest that lithium effects in mice in the forced-swim test are dose dependent but not owing to lithium-induced weight loss.

  9. Antimicrobial Activity.

    PubMed

    2016-01-01

    Natural products of higher plants may possess a new source of antimicrobial agents with possibly novel mechanisms of action. They are effective in the treatment of infectious diseases while simultaneously mitigating many of the side effects that are often associated with conventional antimicrobials. A method using scanning electron microscope (SEM) to study the morphology of the bacterial and fungal microbes and thus determining antimicrobial activity is presented in the chapter.

  10. Analgesic Activity.

    PubMed

    2016-01-01

    Analgesics are agents which selectively relieve pain by acting in the CNS and peripheral pain mediators without changing consciousness. Analgesics may be narcotic or non-narcotic. The study of pain in animals raises ethical, philosophical, and technical problems. Both peripheral and central pain models are included to make the test more evident for the analgesic property of the plant. This chapter highlights methods such as hot plate and formalin and acetic acid-induced pain models to check the analgesic activity of medicinal plants.

  11. Active packaging with antifungal activities.

    PubMed

    Nguyen Van Long, N; Joly, Catherine; Dantigny, Philippe

    2016-03-02

    There have been many reviews concerned with antimicrobial food packaging, and with the use of antifungal compounds, but none provided an exhaustive picture of the applications of active packaging to control fungal spoilage. Very recently, many studies have been done in these fields, therefore it is timely to review this topic. This article examines the effects of essential oils, preservatives, natural products, chemical fungicides, nanoparticles coated to different films, and chitosan in vitro on the growth of moulds, but also in vivo on the mould free shelf-life of bread, cheese, and fresh fruits and vegetables. A short section is also dedicated to yeasts. All the applications are described from a microbiological point of view, and these were sorted depending on the name of the species. Methods and results obtained are discussed. Essential oils and preservatives were ranked by increased efficacy on mould growth. For all the tested molecules, Penicillium species were shown more sensitive than Aspergillus species. However, comparison between the results was difficult because it appeared that the efficiency of active packaging depended greatly on the environmental factors of food such as water activity, pH, temperature, NaCl concentration, the nature, the size, and the mode of application of the films, in addition to the fact that the amount of released antifungal compounds was not constant with time. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Functional magnetic resonance imaging of motor cortex activation in schizophrenia.

    PubMed

    Lee, Hyo Jong; Preda, Adrian; Ford, Judith M; Mathalon, Daniel H; Keator, David B; van Erp, Theo G M; Turner, Jessica A; Potkin, Steven G

    2015-05-01

    Previous fMRI studies of sensorimotor activation in schizophrenia have found in some cases hypoactivity, no difference, or hyperactivity when comparing patients with controls; similar disagreement exists in studies of motor laterality. In this multi-site fMRI study of a sensorimotor task in individuals with chronic schizophrenia and matched healthy controls, subjects responded with a right-handed finger press to an irregularly flashing visual checker board. The analysis includes eighty-five subjects with schizophrenia diagnosed according to the DSM-IV criteria and eighty-six healthy volunteer subjects. Voxel-wise statistical parametric maps were generated for each subject and analyzed for group differences; the percent Blood Oxygenation Level Dependent (BOLD) signal changes were also calculated over predefined anatomical regions of the primary sensory, motor, and visual cortex. Both healthy controls and subjects with schizophrenia showed strongly lateralized activation in the precentral gyrus, inferior frontal gyrus, and inferior parietal lobule, and strong activations in the visual cortex. There were no significant differences between subjects with schizophrenia and controls in this multi-site fMRI study. Furthermore, there was no significant difference in laterality found between healthy controls and schizophrenic subjects. This study can serve as a baseline measurement of schizophrenic dysfunction in other cognitive processes.

  13. Brain Activation Underlying Threat Detection to Targets of Different Races

    PubMed Central

    Senholzi, Keith B.; Depue, Brendan E.; Correll, Joshua; Banich, Marie T.; Ito, Tiffany A.

    2016-01-01

    The current study examined blood oxygen level dependent (BOLD) signal underlying racial differences in threat detection. During fMRI, participants determined whether pictures of Black or White individuals held weapons. They were instructed to make shoot responses when the picture showed armed individuals but don’t shoot responses to unarmed individuals, with the cost of not shooting armed individuals being greater than that of shooting unarmed individuals. Participants were faster to shoot armed Blacks than Whites, but faster in making don’t shoot responses to unarmed Whites than Blacks. Brain activity differed to armed versus unarmed targets depending on target race, suggesting different mechanisms underlying threat versus safety decisions. Anterior cingulate cortex was preferentially engaged for unarmed Whites than Blacks. Parietal and visual cortical regions exhibited greater activity for armed Blacks than Whites. Seed-based functional connectivity of the amygdala revealed greater coherence with parietal and visual cortices for armed Blacks than Whites. Furthermore, greater implicit Black-danger associations were associated with increased amygdala activation to armed Blacks, compared to armed Whites. Our results suggest that different neural mechanisms may underlie racial differences in responses to armed versus unarmed targets. PMID:26357911

  14. Parsing brain activity associated with acupuncture treatment in Parkinson's diseases.

    PubMed

    Chae, Younbyoung; Lee, Hyejung; Kim, Hackjin; Kim, Chang-Hwan; Chang, Dae-Il; Kim, Kyung-Mi; Park, Hi-Joon

    2009-09-15

    Acupuncture, a common treatment modality within complementary and alternative medicine, has been widely used for Parkinson's disease (PD). Using functional magnetic resonance imaging (fMRI), we explored the neural mechanisms underlying the effect of specific and genuine acupuncture treatment on the motor function in patients with PD. Three fMRI scans were performed in random order in a block design, one for verum acupuncture (VA) treatment, another one for a covert placebo (CP), and the third one for an overt placebo (OP) at the motor function implicated acupoint GB34 on the left foot of 10 patients with PD. We calculated the contrast that subtracts the blood-oxygen-level dependent (BOLD) response for the acupuncture effect (VA vs. CP) and the placebo effect (CP vs. OP). We found a significant improvement in the motor function of the affected hand after acupuncture treatment. The putamen and the primary motor cortex were activated when patients with PD received the acupuncture treatment (VA vs. CP) and these activations correlated with individual enhanced motor function. Expectation towards acupuncture modality (CP vs. OP) elicited activation over the anterior cingulate gyrus, the superior frontal gyrus, and the superior temporal gyrus. These findings suggest that acupuncture treatment might facilitate improvement in the motor functioning of patients with PD via the basal ganglia-thalamocortical circuit.

  15. Face gender modulates women's brain activity during face encoding.

    PubMed

    Lovén, Johanna; Svärd, Joakim; Ebner, Natalie C; Herlitz, Agneta; Fischer, Håkan

    2014-07-01

    Women typically remember more female than male faces, whereas men do not show a reliable own-gender bias. However, little is known about the neural correlates of this own-gender bias in face recognition memory. Using functional magnetic resonance imaging (fMRI), we investigated whether face gender modulated brain activity in fusiform and inferior occipital gyri during incidental encoding of faces. Fifteen women and 14 men underwent fMRI while passively viewing female and male faces, followed by a surprise face recognition task. Women recognized more female than male faces and showed higher activity to female than male faces in individually defined regions of fusiform and inferior occipital gyri. In contrast, men's recognition memory and blood-oxygen-level-dependent response were not modulated by face gender. Importantly, higher activity in the left fusiform gyrus (FFG) to one gender was related to better memory performance for that gender. These findings suggest that the FFG is involved in the gender bias in memory for faces, which may be linked to differential experience with female and male faces. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  16. Active tectonics

    SciTech Connect

    Not Available

    1986-01-01

    This study is part of a series of Studies in Geophysics that have been undertaken for the Geophysics Research Forum by the Geophysics Study Committee. One purpose of each study is to provide assessments from the scientific community to aid policymakers in decisions on societal problems that involve geophysics. An important part of such assessments is an evaluation of the adequacy of current geophysical knowledge and the appropriateness of current research programs as a source of information required for those decisions. The study addresses our current scientific understanding of active tectonics --- particularly the patterns and rates of ongoing tectonic processes. Many of these processes cannot be described reasonably using the limited instrumental or historical records; however, most can be described adequately for practical purposes using the geologic record of the past 500,000 years. A program of fundamental research focusing especially on Quaternary tectonic geology and geomorphology, paleoseismology, neotectonics, and geodesy is recommended to better understand ongoing, active tectonic processes. This volume contains 16 papers. Individual papers are indexed separately on the Energy Database.

  17. Depression of cortical activity in humans by mild hypercapnia.

    PubMed

    Thesen, Thomas; Leontiev, Oleg; Song, Tao; Dehghani, Nima; Hagler, Donald J; Huang, Mingxiong; Buxton, Richard; Halgren, Eric

    2012-03-01

    The effects of neural activity on cerebral hemodynamics underlie human brain imaging with functional magnetic resonance imaging and positron emission tomography. However, the threshold and characteristics of the converse effects, wherein the cerebral hemodynamic and metabolic milieu influence neural activity, remain unclear. We tested whether mild hypercapnia (5% CO2 ) decreases the magnetoencephalogram response to auditory pattern recognition and visual semantic tasks. Hypercapnia induced statistically significant decreases in event-related fields without affecting behavioral performance. Decreases were observed in early sensory components in both auditory and visual modalities as well as later cognitive components related to memory and language. Effects were distributed across cortical regions. Decreases were comparable in evoked versus spontaneous spectral power. Hypercapnia is commonly used with hemodynamic models to calibrate the blood oxygenation level-dependent response. Modifying model assumptions to incorporate the current findings produce a modest but measurable decrease in the estimated cerebral metabolic rate for oxygen change with activation. Because under normal conditions, low cerebral pH would arise when bloodflow is unable to keep pace with neuronal activity, the cortical depression observed here may reflect a homeostatic mechanism by which neuronal activity is adjusted to a level that can be sustained by available bloodflow. Animal studies suggest that these effects may be mediated by pH-modulating presynaptic adenosine receptors. Although the data is not clear, comparable changes in cortical pH to those induced here may occur during sleep apnea, sleep, and exercise. If so, these results suggest that such activities may in turn have generalized depressive effects on cortical activity.

  18. Depression of Cortical Activity in Humans by Mild Hypercapnia

    PubMed Central

    Thesen, Thomas; Leontiev, Oleg; Song, Tao; Dehghani, Nima; Hagler, Donald J; Huang, Mingxiong; Buxton, Richard; Halgren, Eric

    2013-01-01

    The effects of neural activity on cerebral hemodynamics underlie human brain imaging with functional magnetic resonance imaging and positron emission tomography. However, the threshold and characteristics of the converse effects, wherein the cerebral hemodynamic and metabolic milieu influence neural activity, remain unclear. We tested whether mild hypercapnia (5% CO2) decreases the magnetoencephalogram response to auditory pattern recognition and visual semantic tasks. Hypercapnia induced statistically significant decreases in event-related fields without affecting behavioral performance. Decreases were observed in early sensory components in both auditory and visual modalities as well as later cognitive components related to memory and language. Effects were distributed across cortical regions. Decreases were comparable in evoked versus spontaneous spectral power. Hypercapnia is commonly used with hemodynamic models to calibrate the blood oxygenation level-dependent response. Modifying model assumptions to incorporate the current findings produce a modest but measurable decrease in the estimated cerebral metabolic rate for oxygen change with activation. Because under normal conditions, low cerebral pH would arise when bloodflow is unable to keep pace with neuronal activity, the cortical depression observed here may reflect a homeostatic mechanism by which neuronal activity is adjusted to a level that can be sustained by available bloodflow. Animal studies suggest that these effects may be mediated by pH-modulating presynaptic adenosine receptors. Although the data is not clear, comparable changes in cortical pH to those induced here may occur during sleep apnea, sleep, and exercise. If so, these results suggest that such activities may in turn have generalized depressive effects on cortical activity. PMID:21500313

  19. N-methyl-D-aspartate receptor encephalitis mediates loss of intrinsic activity measured by functional MRI.

    PubMed

    Brier, Matthew R; Day, Gregory S; Snyder, Abraham Z; Tanenbaum, Aaron B; Ances, Beau M

    2016-06-01

    Spontaneous brain activity is required for the development and maintenance of normal brain function. Many disease processes disrupt the organization of intrinsic brain activity, but few pervasively reduce the amplitude of resting state blood oxygen level dependent (BOLD) fMRI fluctuations. We report the case of a female with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, longitudinally studied during the course of her illness to determine the contribution of NMDAR signaling to spontaneous brain activity. Resting state BOLD fMRI was measured at the height of her illness and 18 weeks following discharge from hospital. Conventional resting state networks were defined using established methods. Correlation and covariance matrices were calculated by extracting the BOLD time series from regions of interest and calculating either the correlation or covariance quantity. The intrinsic activity was compared between visits, and to expected activity from 45 similarly aged healthy individuals. Near the height of the illness, the patient exhibited profound loss of consciousness, high-amplitude slowing of the electroencephalogram, and a severe reduction in the amplitude of spontaneous BOLD fMRI fluctuations. The patient's neurological status and measures of intrinsic activity improved following treatment. We conclude that NMDAR-mediated signaling plays a critical role in the mechanisms that give rise to organized spontaneous brain activity. Loss of intrinsic activity is associated with profound disruptions of consciousness and cognition.

  20. Quantitative evaluation of activation state in functional brain imaging.

    PubMed

    Hu, Zhenghui; Ni, Pengyu; Liu, Cong; Zhao, Xiaohu; Liu, Huafeng; Shi, Pengcheng

    2012-10-01

    Neuronal activity can evoke the hemodynamic change that gives rise to the observed functional magnetic resonance imaging (fMRI) signal. These increases are also regulated by the resting blood volume fraction (V (0)) associated with regional vasculature. The activation locus detected by means of the change in the blood-oxygen-level-dependent (BOLD) signal intensity thereby may deviate from the actual active site due to varied vascular density in the cortex. Furthermore, conventional detection techniques evaluate the statistical significance of the hemodynamic observations. In this sense, the significance level relies not only upon the intensity of the BOLD signal change, but also upon the spatially inhomogeneous fMRI noise distribution that complicates the expression of the results. In this paper, we propose a quantitative strategy for the calibration of activation states to address these challenging problems. The quantitative assessment is based on the estimated neuronal efficacy parameter [Formula: see text] of the hemodynamic model in a voxel-by-voxel way. It is partly immune to the inhomogeneous fMRI noise by virtue of the strength of the optimization strategy. Moreover, it is easy to incorporate regional vascular information into the activation detection procedure. By combining MR angiography images, this approach can remove large vessel contamination in fMRI signals, and provide more accurate functional localization than classical statistical techniques for clinical applications. It is also helpful to investigate the nonlinear nature of the coupling between synaptic activity and the evoked BOLD response. The proposed method might be considered as a potentially useful complement to existing statistical approaches.

  1. Solar activity

    NASA Astrophysics Data System (ADS)

    Rust, D. M.

    1983-03-01

    The increased data base and scope of the theoretical models for solar flares are reviewed. Data have been gathered from the Skylab instrumentation, the Solar Maximum Mission, and the Very Large Array. Skylab X ray images revealed regularly spaced bright spots on the solar surface. Studies have also been performed on the emergence of magnetic fields, the coronal structures defined by magnetic fields above active regions, and the behavior and composition of post-flare loops. It has been found that coronal transients are associated with eruptive prominences with and without flares up to 70 pct of the time. Two classes of solar flares have been identified, i.e., small volume, low altitude with a short rise time, and long decay events with a larger coronal loop structure. Evidence for thermal and nonthermal causes for the electron velocity distribution in the flares is discussed. Finally, SMM data has shown chromospheric reactions to magnetic field variations in the photosphere and the response of the interplanetary medium to coronal transients.

  2. Active Segmentation

    PubMed Central

    Mishra, Ajay; Aloimonos, Yiannis

    2009-01-01

    The human visual system observes and understands a scene/image by making a series of fixations. Every fixation point lies inside a particular region of arbitrary shape and size in the scene which can either be an object or just a part of it. We define as a basic segmentation problem the task of segmenting that region containing the fixation point. Segmenting the region containing the fixation is equivalent to finding the enclosing contour- a connected set of boundary edge fragments in the edge map of the scene - around the fixation. This enclosing contour should be a depth boundary. We present here a novel algorithm that finds this bounding contour and achieves the segmentation of one object, given the fixation. The proposed segmentation framework combines monocular cues (color/intensity/texture) with stereo and/or motion, in a cue independent manner. The semantic robots of the immediate future will be able to use this algorithm to automatically find objects in any environment. The capability of automatically segmenting objects in their visual field can bring the visual processing to the next level. Our approach is different from current approaches. While existing work attempts to segment the whole scene at once into many areas, we segment only one image region, specifically the one containing the fixation point. Experiments with real imagery collected by our active robot and from the known databases 1 demonstrate the promise of the approach. PMID:20686671

  3. IASS Activity

    NASA Astrophysics Data System (ADS)

    Hojaev, Alisher S.; Ibragimova, Elvira M.

    2015-08-01

    It’s well known, astronomy in Uzbekistan has ancient roots and traditions (e.g., Mirzo Ulugh Beg, Abū al-Rayhān al-Bīrūnī, Abū ‘Abdallāh al-Khwārizmī) and astronomical heritage carefully preserved. Nowadays uzbek astronomers play a key role in scientific research but also in OAD and Decadal Plan activity in the Central Asia region. International Aerospace School (IASS) is an amazing and wonderful event held annually about 30 years. IASS is unique project in the region, and at the beginning we spent the Summer and Winter Schools. At present in the summer camp we gather about 50 teenage and undergraduate students over the country and abroad (France, Malaysia, Turkey, Azerbaijan, Pakistan, Russia, etc.). They are selected on the basis of tests of astronomy and space issues. During two weeks of IASS camp the invited scientists, cosmonauts and astronauts as well as other specialists give lectures and engage in practical exercises with IASS students in astronomy, including daily observations of the Sun and night sky observations with meniscus telescope, space research and exploration, aerospace modelling, preparation and presentation of original projects. This is important that IASS gives not theoretical grounds only but also practically train the students and the hands-on training is the major aims of IASS. Lectures and practice in the field of astronomy carried out with the direct involvement and generous assistance of Uranoscope Association (Paris, France). The current 26-th IASS is planned to held in July 2015.

  4. Brain activity associated with the electrodermal reactivity to acute heat pain.

    PubMed

    Dubé, Audrey-Anne; Duquette, Marco; Roy, Mathieu; Lepore, Franco; Duncan, Gary; Rainville, Pierre

    2009-03-01

    Pain is associated with the activation of many brain areas involved in the multiple dimensions of the experience. Several of those brain areas may also contribute to the monitoring and regulation of autonomic activity but this aspect of pain responses has been largely overlooked in human imaging studies. This functional magnetic resonance imaging (fMRI) study relied on blood-oxygen level dependent (BOLD) signal to investigate subject-related differences in brain activity associated with the individual differences in electrodermal responses evoked by 30 s noxious (pain) and innocuous (warm) thermal stimuli. Pain-related activity (pain-warm) was found in the thalamus, somatosensory cortices (leg area of SI/MI, SII, and insula), the anterior cingulate cortex (ACC), and the amygdala. Brain activation related to stimulus-evoked electrodermal activity was identified by modeling the predicted BOLD responses with the magnitude of each subject's skin conductance reactivity. Subjects showing larger skin conductance reactivity to the innocuous and/or noxious stimuli displayed larger stimulus-evoked brain responses in the somato-motor cortices (SI/MI, SII, and insula), the perigenual and supracallosal ACC, the orbitofrontal cortex and the medulla. Further analyses revealed brain activation more specifically associated with the pain-related skin conductance reactivity in the supracallosal ACC, amygdala, thalamus, and hypothalamus. These findings demonstrate that individual differences in electrodermal reactivity partly reflect differences in pain-evoked brain responses, consistent with a role of these structures in the monitoring/regulation of pain-related autonomic processes.

  5. An investigation of the relationship between activation of a social cognitive neural network and social functioning.

    PubMed

    Pinkham, Amy E; Hopfinger, Joseph B; Ruparel, Kosha; Penn, David L

    2008-07-01

    Previous work examining the neurobiological substrates of social cognition in healthy individuals has reported modulation of a social cognitive network such that increased activation of the amygdala, fusiform gyrus, and superior temporal sulcus are evident when individuals judge a face to be untrustworthy as compared with trustworthy. We examined whether this pattern would be present in individuals with schizophrenia who are known to show reduced activation within these same neural regions when processing faces. Additionally, we sought to determine how modulation of this social cognitive network may relate to social functioning. Neural activation was measured using functional magnetic resonance imaging with blood oxygenation level dependent contrast in 3 groups of individuals--nonparanoid individuals with schizophrenia, paranoid individuals with schizophrenia, and healthy controls--while they rated faces as either trustworthy or untrustworthy. Analyses of mean percent signal change extracted from a priori regions of interest demonstrated that both controls and nonparanoid individuals with schizophrenia showed greater activation of this social cognitive network when they rated a face as untrustworthy relative to trustworthy. In contrast, paranoid individuals did not show a significant difference in levels of activation based on how they rated faces. Further, greater activation of this social cognitive network to untrustworthy faces was significantly and positively correlated with social functioning. These findings indicate that impaired modulation of neural activity while processing social stimuli may underlie deficits in social cognition and social dysfunction in schizophrenia.

  6. BOLD fMRI activation induced by vagus nerve stimulation in seizure patients

    PubMed Central

    Liu, W; Mosier, K; Kalnin, A; Marks, D

    2003-01-01

    Design: Blood oxygenation level dependent functional magnetic resonance imaging (BOLD fMRI) was employed to detect areas of the brain activated by vagus nerve stimulation in five patients with documented complex partial seizures. Methods: Functional MRI was done on a GE 1.5T Echospeed horizon scanner. Before each patient entered the scanner, the vagal nerve stimulator was set to a specific ON–OFF paradigm so that the data could be analysed using a box-car type of design. The brains were scanned both anatomically and functionally. The functional images were corrected for head motion and co-registered to the anatomical images. Maps of the activated areas were generated and analysed using the brain mapping software, SPM99. The threshold for activation was chosen as p < 0.001. Results: All patients showed activation in the frontal and occipital lobes. However, activation in the thalamus was seen only in the two patients with improved seizure control. Conclusions: BOLD fMRI can detect activation associated with vagus nerve stimulation. There may be a relation between thalamic activation and a favourable clinical outcome. PMID:12754361

  7. Physical Activity (Exercise)

    MedlinePlus

    ... Physical activity (exercise) fact sheet ePublications Physical activity (exercise) fact sheet How can physical activity improve my ... recent hip surgery More information on physical activity (exercise) For more information about physical activity (exercise), call ...

  8. The synchronization of spontaneous BOLD activity predicts extraversion and neuroticism.

    PubMed

    Wei, Luqing; Duan, Xujun; Yang, Yang; Liao, Wei; Gao, Qing; Ding, Ju-rong; Zhang, Zhiqiang; Zeng, Weixi; Li, Yuan; Lu, Guangming; Chen, Huafu

    2011-10-24

    There is an increasing body of evidence pointing to a relationship between personality and brain markers. The purpose of this study was to identify the associations between personality dimensions of extraversion and neuroticism and the local synchronization of spontaneous blood oxygen level-dependent (BOLD) activity assessed by regional homogeneity (ReHo) approach. Our results revealed the significant negative correlation between neuroticism and ReHo in the left middle frontal gyrus, providing evidence for the left frontal activation involved in pleasant emotion. ReHo was correlated negatively with extraversion in the medial prefrontal cortex (MPFC), an important portion of the default mode network (DMN), thus further indicating the relationship between DMN and personality. In addition, ReHo in the insula, cerebellum and cingulate gyrus was correlated positively with extraversion, suggesting the associations between individual difference in extraversion and specific brain regions involved in affective processing. These findings shed light on the important relationship between the synchronization of spontaneous fluctuations and personality dimensions of extraversion and neuroticism, which provide further evidence for the neural underpinning of individual difference in personality traits.

  9. Metabolic activity of permafrost bacteria below the freezing point

    NASA Technical Reports Server (NTRS)

    Rivkina, E. M.; Friedmann, E. I.; McKay, C. P.; Gilichinsky, D. A.

    2000-01-01

    Metabolic activity was measured in the laboratory at temperatures between 5 and -20 degrees C on the basis of incorporation of (14)C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5 degrees C) to 20 days (-10 degrees C) to ca. 160 days (-20 degrees C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature.

  10. Metabolic Activity of Permafrost Bacteria below the Freezing Point

    PubMed Central

    Rivkina, E. M.; Friedmann, E. I.; McKay, C. P.; Gilichinsky, D. A.

    2000-01-01

    Metabolic activity was measured in the laboratory at temperatures between 5 and −20°C on the basis of incorporation of 14C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5°C) to 20 days (−10°C) to ca. 160 days (−20°C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature. PMID:10919774

  11. Alteration of spontaneous brain activity in COPD patients.

    PubMed

    Zhang, Jiaxing; Chen, Ji; Yu, Qian; Fan, Cunxiu; Zhang, Ran; Lin, Jianzhong; Yang, Tianhe; Fan, Ming

    2016-01-01

    Airflow limitation in chronic obstructive pulmonary disease (COPD) results in a decrease in oxygen transport to the brain. The aim of the present study was to explore the alteration of spontaneous brain activity induced by hypoxia in patients with COPD. Twenty-five stable patients with COPD and 25 matching healthy volunteers were investigated. Amplitude of low-frequency fluctuation (ALFF) of blood oxygenation level-dependent signal at resting state in the brain was analyzed using functional magnetic resonance imaging. Whole-brain analysis using functional magnetic resonance imaging revealed significant decreases in ALFF in the bilateral posterior cingulate gyri and right lingual gyrus and an increase in ALFF in the left postcentral gyrus of patients with COPD. After controlling for SaO2, patients with COPD only showed an increase in ALFF in the left postcentral gyrus. Region of interest analysis showed a decrease in ALFF in the left precentral gyrus and an increase in ALFF in the left caudate nucleus of patients with COPD. In all subjects, ALFF in the bilateral posterior cingulate gyri and right lingual gyrus showed positive correlations with visual reproduction. We demonstrated abnormal spontaneous brain activity of patients with COPD, which may have a pathophysiologic meaning.

  12. Metabolic activity of permafrost bacteria below the freezing point.

    PubMed

    Rivkina, E M; Friedmann, E I; McKay, C P; Gilichinsky, D A

    2000-08-01

    Metabolic activity was measured in the laboratory at temperatures between 5 and -20 degrees C on the basis of incorporation of (14)C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5 degrees C) to 20 days (-10 degrees C) to ca. 160 days (-20 degrees C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature.

  13. Alteration of spontaneous brain activity in COPD patients

    PubMed Central

    Zhang, Jiaxing; Chen, Ji; Yu, Qian; Fan, Cunxiu; Zhang, Ran; Lin, Jianzhong; Yang, Tianhe; Fan, Ming

    2016-01-01

    Background and objective Airflow limitation in chronic obstructive pulmonary disease (COPD) results in a decrease in oxygen transport to the brain. The aim of the present study was to explore the alteration of spontaneous brain activity induced by hypoxia in patients with COPD. Patients and methods Twenty-five stable patients with COPD and 25 matching healthy volunteers were investigated. Amplitude of low-frequency fluctuation (ALFF) of blood oxygenation level-dependent signal at resting state in the brain was analyzed using functional magnetic resonance imaging. Results Whole-brain analysis using functional magnetic resonance imaging revealed significant decreases in ALFF in the bilateral posterior cingulate gyri and right lingual gyrus and an increase in ALFF in the left postcentral gyrus of patients with COPD. After controlling for SaO2, patients with COPD only showed an increase in ALFF in the left postcentral gyrus. Region of interest analysis showed a decrease in ALFF in the left precentral gyrus and an increase in ALFF in the left caudate nucleus of patients with COPD. In all subjects, ALFF in the bilateral posterior cingulate gyri and right lingual gyrus showed positive correlations with visual reproduction. Conclusion We demonstrated abnormal spontaneous brain activity of patients with COPD, which may have a pathophysiologic meaning. PMID:27555761

  14. Spatiotemporal characteristics of electrocortical brain activity during mental calculation.

    PubMed

    Vansteensel, Mariska J; Bleichner, Martin G; Freudenburg, Zac V; Hermes, Dora; Aarnoutse, Erik J; Leijten, Frans S S; Ferrier, Cyrille H; Jansma, Johan Martijn; Ramsey, Nick F

    2014-12-01

    Mental calculation is a complex mental procedure involving a frontoparietal network of brain regions. Functional MRI (fMRI) studies have revealed interesting characteristics of these regions, but the precise function of some areas remains elusive. In the present study, we used electrocorticographic (ECoG) recordings to chronometrically assess the neuronal processes during mental arithmetic. A calculation task was performed during presurgical 3T fMRI scanning and subsequent ECoG monitoring. Mental calculation induced an increase in fMRI blood oxygen level dependent signal in prefrontal, parietal and lower temporo-occipital regions. The group-fMRI result was subsequently used to cluster the implanted electrodes into anatomically defined regions of interest (ROIs). We observed remarkable differences in high frequency power profiles between ROIs, some of which were closely associated with stimulus presentation and others with the response. Upon stimulus presentation, occipital areas were the first to respond, followed by parietal and frontal areas, and finally by motor areas. Notably, we demonstrate that the fMRI activation in the middle frontal gyrus/precentral gyrus is associated with two subfunctions during mental calculation. This finding reveals the significance of the temporal dynamics of neural ensembles within regions with an apparent uniform function. In conclusion, our results shed more light on the spatiotemporal aspects of brain activation during a mental calculation task, and demonstrate that the use of fMRI data to cluster ECoG electrodes is a useful approach for ECoG group analysis.

  15. Metabolic activity of permafrost bacteria below the freezing point

    NASA Technical Reports Server (NTRS)

    Rivkina, E. M.; Friedmann, E. I.; McKay, C. P.; Gilichinsky, D. A.

    2000-01-01

    Metabolic activity was measured in the laboratory at temperatures between 5 and -20 degrees C on the basis of incorporation of (14)C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5 degrees C) to 20 days (-10 degrees C) to ca. 160 days (-20 degrees C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature.

  16. Activation Energy

    NASA Technical Reports Server (NTRS)

    Gadeken, Owen

    2002-01-01

    Teaming is so common in today's project management environment that most of us assume it comes naturally. We further assume that when presented with meaningful and challenging work, project teams will naturally engage in productive activity to complete their tasks. This assumption is expressed in the simple (but false) equation: Team + Work = Teamwork. Although this equation appears simple and straightforward, it is far from true for most project organizations whose reality is a complex web of institutional norms based on individual achievement and rewards. This is illustrated by the very first successful team experience from my early Air Force career. As a young lieutenant, I was sent to Squadron Officer School, which was the first in the series of Air Force professional military education courses I was required to complete during my career. We were immediately formed into teams of twelve officers. Much of the course featured competition between these teams. As the most junior member of my team, I quickly observed the tremendous pressure to show individual leadership capability. At one point early in the course, almost everyone in our group was vying to become the team leader. This conflict was so intense that it caused us to fail miserably in our first outdoor team building exercise. We spent so much time fighting over leadership that we were unable to complete any of the events on the outdoor obstacle course. This complete lack of success was so disheartening to me that I gave our team little hope for future success. What followed was a very intense period of bickering, conflict, and even shouting matches as our dysfunctional team tried to cope with our early failures and find some way to succeed. British physician and researcher Wilfred Bion (Experiences in Groups, 1961) discovered that there are powerful psychological forces inherent in all groups that divert from accomplishing their primary tasks. To overcome these restraining forces and use the potential

  17. Arabidopsis glucosyltransferases with activities toward both endogenous and xenobiotic substrates.

    PubMed

    Messner, Burkhard; Thulke, Oliver; Schäffner, Anton R

    2003-05-01

    Arabidopsis thaliana Heynh. harbors UDP-glucose-dependent glucosyltransferase (UGT; EC 2.4.1.-) activities that are able to glucosylate xenobiotic substrates as a crucial step in their detoxification, similar to other plants. However, it has remained elusive whether side-activities of UGTs acting on endogenous substrates could account for that property. Therefore, seven recombinantly expressed A. thaliana enzymes were tested using the phytotoxic xenobiotic model compound 2,4,5-trichlorophenol (TCP) as a substrate. The enzymes were selected from the large Arabidopsis UGT gene family because their previously identified putative endogenous substrates comprised both carboxylic acid, and phenolic and aliphatic hydroxyl moieties as biochemical targets. In addition, UGT75D1, which was shown to accept the endogenous flavonoid kaempferol as a substrate, was included. All enzymes tested, except the sterol-conjugating UGT80A2, glucosylated TCP as a parallel activity. The K(m) values for TCP ranged from 0.059 to 1.25 mM. When tested at saturating concentrations of the native substrates the glucosylation of TCP by the glucose-ester-forming UGT84A1 and UGT84A2 was suppressed by p-coumaric acid and sinapic acid, respectively. In contrast, the activities of UGT72E2 and UGT75D1 toward their phenolic native substrates and the xenobiotic TCP were mutually inhibited. TCP was a competitive inhibitor of sinapyl alcohol glucosylation by UGT72E2. These overlapping in vitro activities suggest cross-talk between the detoxification of xenobiotics and endogenous metabolism at the biochemical level, depending on the presence of competing substrates and enzymes.

  18. Influence of hormonal status on enkephalin-degrading aminopeptidase activity in the HPA axis of female mice.

    PubMed

    García-López, M J; Martínez-Martos, J M; Mayas, M D; Carrera, M P; Ramírez-Expósito, M J

    2005-04-01

    Opioids are involved in the regulation of hypothalamus-pituitary-adrenal (HPA) axis activity under physiological conditions. In the present work, we analyzed the influence of ovariectomy and estradiol (E), progesterone (P) or estradiol plus progesterone (E+P) replacement on soluble (S) and membrane-bound (MB) enkephalin-degrading aminopeptidase activity (EDA) in the HPA axis. Female mice (Balb/C) were distributed in 15 groups of 10 animals each: sham-operated controls (C), ovariectomized controls (OV-C), and ovariectomized mice treated with increasing doses of E (10, 20 or 40 mg/kg), P (100, 200 or 400 mg/kg) or E+P (10+100, 20+200 or 40+400 mg/kg). In hypothalamus, ovariectomy increased both S and MB EDA activities, whereas E replacement returned them to control levels, although MB EDA activity increased again after the replacement with 40 mg/kg E. P replacement increased S EDA activity, but returned MB EDA activity to control levels. The replacement of E+P returned both S and MB EDA activities to control levels, although MB EDA activity was lower than control values after the replacement with 10+100 mg/kg E+P. In pituitary, neither ovariectomy nor the replacement of E or E+P changed S EDA, although the highest concentrations of P increased S EDA activity. However, ovariectomy increased MB EDA and E replacement returned the activity to control or below control levels, depending on the concentration used. However, P administration returned the activity to control or below control levels depending on the concentration used, although 200 mg/kg P had no effects on MB EDA. E+P replacement returned pituitary MB EDA activity to control levels. In adrenal glands, ovariectomy did change either S or MB EDA. However, E, P or E+P replacement decreased S EDA activity in different degrees, depending of the dose administrated. No changes were detected in MB EDA after hormone replacement. These results indicate that female steroid hormones influence EDA activity at different

  19. Force-endurance capabilities of extravehicular activity (EVA) gloves at different pressure levels

    NASA Technical Reports Server (NTRS)

    Bishu, Ram R.; Klute, Glenn K.

    1993-01-01

    The human hand is a very useful multipurpose tool in all environments. However, performance capabilities are compromised considerably when gloves are donned. This is especially true to extravehicular activity (EVA) gloves. The primary intent was to answer the question of how long a person can perform tasks requiring certain levels of exertion. The objective was to develop grip force-endurance relations. Six subjects participated in a factorial experiment involving three hand conditions, three pressure differentials, and four levels of force exertion. The results indicate that, while the force that could be exerted depended on the glove, pressure differential, and the level of exertion, the endurance time at any exertion level depended just on the level of exertion expressed as a percentage of maximum exertion possible at that condition. The impact of these findings for practitioners as well as theoreticians is discussed.

  20. Arousal Modulates Activity in the Medial Temporal Lobe during a Short-Term Relational Memory Task

    PubMed Central

    Thoresen, Christian; Jensen, Jimmy; Sigvartsen, Niels Petter B.; Bolstad, Ingeborg; Server, Andres; Nakstad, Per H.; Andreassen, Ole A.; Endestad, Tor

    2011-01-01

    This study investigated the effect of arousal on short-term relational memory and its underlying cortical network. Seventeen healthy participants performed a picture by location, short-term relational memory task using emotional pictures. Functional magnetic resonance imaging was used to measure the blood-oxygenation-level dependent signal relative to task. Subjects’ own ratings of the pictures were used to obtain subjective arousal ratings. Subjective arousal was found to have a dose-dependent effect on activations in the prefrontal cortex, amygdala, hippocampus, and in higher order visual areas. Serial position analyses showed that high arousal trials produced a stronger primacy and recency effect than low arousal trials. The results indicate that short-term relational memory may be facilitated by arousal and that this may be modulated by a dose–response function in arousal-driven neuronal regions. PMID:22291626

  1. In vivo outer hair cell length changes expose the active process in the cochlea.

    PubMed

    Zha, Dingjun; Chen, Fangyi; Ramamoorthy, Sripriya; Fridberger, Anders; Choudhury, Niloy; Jacques, Steven L; Wang, Ruikang K; Nuttall, Alfred L

    2012-01-01

    Mammalian hearing is refined by amplification of the sound-evoked vibration of the cochlear partition. This amplification is at least partly due to forces produced by protein motors residing in the cylindrical body of the outer hair cell. To transmit power to the cochlear partition, it is required that the outer hair cells dynamically change their length, in addition to generating force. These length changes, which have not previously been measured in vivo, must be correctly timed with the acoustic stimulus to produce amplification. Using in vivo optical coherence tomography, we demonstrate that outer hair cells in living guinea pigs have length changes with unexpected timing and magnitudes that depend on the stimulus level in the sensitive cochlea. The level-dependent length change is a necessary condition for directly validating that power is expended by the active process presumed to underlie normal hearing.

  2. In Vivo Outer Hair Cell Length Changes Expose the Active Process in the Cochlea

    PubMed Central

    Ramamoorthy, Sripriya; Fridberger, Anders; Choudhury, Niloy; Jacques, Steven L.; Wang, Ruikang K.; Nuttall, Alfred L.

    2012-01-01

    Background Mammalian hearing is refined by amplification of the sound-evoked vibration of the cochlear partition. This amplification is at least partly due to forces produced by protein motors residing in the cylindrical body of the outer hair cell. To transmit power to the cochlear partition, it is required that the outer hair cells dynamically change their length, in addition to generating force. These length changes, which have not previously been measured in vivo, must be correctly timed with the acoustic stimulus to produce amplification. Methodology/Principal Findings Using in vivo optical coherence tomography, we demonstrate that outer hair cells in living guinea pigs have length changes with unexpected timing and magnitudes that depend on the stimulus level in the sensitive cochlea. Conclusions/Significance The level-dependent length change is a necessary condition for directly validating that power is expended by the active process presumed to underlie normal hearing. PMID:22496736

  3. Diurnal cortisol amplitude and fronto-limbic activity in response to stressful stimuli.

    PubMed

    Cunningham-Bussel, Amy C; Root, James C; Butler, Tracy; Tuescher, Oliver; Pan, Hong; Epstein, Jane; Weisholtz, Daniel S; Pavony, Michelle; Silverman, Michael E; Goldstein, Martin S; Altemus, Margaret; Cloitre, Marylene; Ledoux, Joseph; McEwen, Bruce; Stern, Emily; Silbersweig, David

    2009-06-01

    The development and exacerbation of many psychiatric and neurologic conditions are associated with dysregulation of the hypothalamic pituitary adrenal (HPA) axis as measured by aberrant levels of cortisol secretion. Here we report on the relationship between the amplitude of diurnal cortisol secretion, measured across 3 typical days in 18 healthy individuals, and blood oxygen level dependant (BOLD) response in limbic fear/stress circuits, elicited by in-scanner presentation of emotionally negative stimuli, specifically, images of the World Trade Center (WTC) attack. Results indicate that subjects who secrete a greater amplitude of cortisol diurnally demonstrate less brain activation in limbic regions, including the amygdala and hippocampus/parahippocampus, and hypothalamus during exposure to traumatic WTC-related images. Such initial findings can begin to link our understanding, in humans, of the relationship between the diurnal amplitude of a hormone integral to the stress response, and those neuroanatomical regions that are implicated as both modulating and being modulated by that response.

  4. Carbohydrate in the mouth enhances activation of brain circuitry involved in motor performance and sensory perception.

    PubMed

    Turner, Clare E; Byblow, Winston D; Stinear, Cathy M; Gant, Nicholas

    2014-09-01

    The presence of carbohydrate in the human mouth has been associated with the facilitation of motor output and improvements in physical performance. Oral receptors have been identified as a potential mode of afferent transduction for this novel form of nutrient signalling that is distinct from taste. In the current study oral exposure to carbohydrate was combined with a motor task in a neuroimaging environment to identify areas of the brain involved in this phenomenon. A mouth-rinsing protocol was conducted whilst carbohydrate (CHO) and taste-matched placebo (PLA) solutions were delivered and recovered from the mouths of 10 healthy volunteers within a double-blind, counterbalanced design. This protocol eliminates post-oral factors and controls for the perceptual qualities of solutions. Functional magnetic resonance imaging of the brain was used to identify cortical areas responsive to oral carbohydrate during rest and activity phases of a hand-grip motor task. Mean blood-oxygen-level dependent signal change experienced in the contralateral primary sensorimotor cortex was larger for CHO compared with PLA during the motor task when contrasted with a control condition. Areas of activation associated with CHO exclusively were observed over the primary taste cortex and regions involved in visual perception. Regions in the limbic system associated with reward were also significantly more active with CHO. This is the first demonstration that oral carbohydrate signalling can increase activation within the primary sensorimotor cortex during physical activity and enhance activation of neural networks involved in sensory perception.

  5. Imaging seizure activity: a combined EEG/EMG-fMRI study in reading epilepsy.

    PubMed

    Salek-Haddadi, Afraim; Mayer, Thomas; Hamandi, Khalid; Symms, Mark; Josephs, Oliver; Fluegel, Dominique; Woermann, Friedrich; Richardson, Mark P; Noppeney, Uta; Wolf, Peter; Koepp, Matthias J

    2009-02-01

    To characterize the spatial relationship between activations related to language-induced seizure activity, language processing, and motor control in patients with reading epilepsy. We recorded and simultaneously monitored several physiological parameters [voice-recording, electromyography (EMG), electrocardiography (ECG), electroencephalography (EEG)] during blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) in nine patients with reading epilepsy. Individually tailored language paradigms were used to induce and record habitual seizures inside the MRI scanner. Voxel-based morphometry (VBM) was used for structural brain analysis. Reading-induced seizures occurred in six out of nine patients. One patient experienced abundant orofacial reflex myocloni during silent reading in association with bilateral frontal or generalized epileptiform discharges. In a further five patients, symptoms were only elicited while reading aloud with self-indicated events. Consistent activation patterns in response to reading-induced myoclonic seizures were observed within left motor and premotor areas in five of these six patients, in the left striatum (n = 4), in mesiotemporal/limbic areas (n = 4), in Brodmann area 47 (n = 3), and thalamus (n = 2). These BOLD activations were overlapping or adjacent to areas physiologically activated during language and facial motor tasks. No subtle structural abnormalities common to all patients were identified using VBM, but one patient had a left temporal ischemic lesion. Based on the findings, we hypothesize that reflex seizures occur in reading epilepsy when a critical mass of neurons are activated through a provoking stimulus within corticoreticular and corticocortical circuitry subserving normal functions.

  6. Activation of a sensorimotor pathway in response to a water temperature drop in a teleost fish.

    PubMed

    van den Burg, E H; Verhoye, M; Peeters, R R; Meek, J; Flik, G; Van der Linden, A

    2006-06-01

    When common carp, Cyprinus carpio L., experience a rapid temperature drop, the cerebral blood volume is strongly reduced to dampen the temperature drop in the brain. Simultaneously, the preoptic area and pituitary gland are activated to launch whole-body adaptive responses. However, the preferred reaction of fish to a temperature change is an escape reaction, which implies activation of a sensorimotor pathway. Here, we used blood oxygenation level-dependent (BOLD)- and cerebral blood volume (CBV)-weighted functional magnetic resonance imaging (fMRI) to identify a sensorimotor pathway, during a 10 degrees C temperature drop in common carp. Transient activation was observed in the region where the sensory root of the trigeminal nerve enters the brain, and in the valvula cerebelli. In both regions, metabolic activity increased (increased deoxyhemoglobin content demonstrated by a decreased BOLD signal) within 30 s after the onset of the temperature drop, peaked after 2-3 min, and then decreased, even though the temperature continued to drop for another 2 min. These brain structures appear to respond to temperature change, rather than to the absolute temperature. Thus, during a temperature drop, the sensorimotor pathway consisting of the trigeminal nerve, the primary sensory trigeminal nucleus, the valvula cerebelli and some motornuclei, is active, in line with perception of temperature change in the buccal cavity, leading to motor activity for escape. This pathway operates in parallel to an acclimation pathway, which involves the preoptic area to pituitary gland pathway.

  7. The brain's resting-state activity is shaped by synchronized cross-frequency coupling of neural oscillations

    PubMed Central

    Florin, Esther; Baillet, Sylvain

    2015-01-01

    Functional imaging of the resting brain consistently reveals broad motifs of correlated blood oxygen level dependent (BOLD) activity that engage cerebral regions from distinct functional systems. Yet, the neurophysiological processes underlying these organized, large-scale fluctuations remain to be uncovered. Using magnetoencephalography (MEG) imaging during rest in 12 healthy subjects we analyse the resting state networks and their underlying neurophysiology. We first demonstrate non-invasively that cortical occurrences of high-frequency oscillatory activity are conditioned to the phase of slower spontaneous fluctuations in neural ensembles. We further show that resting-state networks emerge from synchronized phase-amplitude coupling across the brain. Overall, these findings suggest a unified principle of local-to-global neural signaling for long-range brain communication. PMID:25680519

  8. Tension-related activity in the orbitofrontal cortex and amygdala: an fMRI study with music

    PubMed Central

    Lehne, Moritz; Rohrmeier, Martin

    2014-01-01

    Tonal music is characterized by a continuous flow of tension and resolution. This flow of tension and resolution is closely related to processes of expectancy and prediction and is a key mediator of music-evoked emotions. However, the neural correlates of subjectively experienced tension and resolution have not yet been investigated. We acquired continuous ratings of musical tension for four piano pieces. In a subsequent functional magnetic resonance imaging experiment, we identified blood oxygen level-dependent signal increases related to musical tension in the left lateral orbitofrontal cortex (pars orbitalis of the inferior frontal gyrus). In addition, a region of interest analysis in bilateral amygdala showed activation in the right superficial amygdala during periods of increasing tension (compared with decreasing tension). This is the first neuroimaging study investigating the time-varying changes of the emotional experience of musical tension, revealing brain activity in key areas of affective processing. PMID:23974947

  9. Tension-related activity in the orbitofrontal cortex and amygdala: an fMRI study with music.

    PubMed

    Lehne, Moritz; Rohrmeier, Martin; Koelsch, Stefan

    2014-10-01

    Tonal music is characterized by a continuous flow of tension and resolution. This flow of tension and resolution is closely related to processes of expectancy and prediction and is a key mediator of music-evoked emotions. However, the neural correlates of subjectively experienced tension and resolution have not yet been investigated. We acquired continuous ratings of musical tension for four piano pieces. In a subsequent functional magnetic resonance imaging experiment, we identified blood oxygen level-dependent signal increases related to musical tension in the left lateral orbitofrontal cortex (pars orbitalis of the inferior frontal gyrus). In addition, a region of interest analysis in bilateral amygdala showed activation in the right superficial amygdala during periods of increasing tension (compared with decreasing tension). This is the first neuroimaging study investigating the time-varying changes of the emotional experience of musical tension, revealing brain activity in key areas of affective processing.

  10. Practice-dependent modulation of neural activity during human sensorimotor coordination: a functional Magnetic Resonance Imaging study.

    PubMed

    Jantzen, K J; Steinberg, F L; Kelso, J A S

    2002-11-08

    We investigated the degree to which differences in the pattern of blood oxygen level dependent activity (BOLD) between syncopated and synchronized coordination patterns are altered by practice. Baseline levels of BOLD activity were obtained from eight subjects while they syncopated or synchronized with an auditory metronome at 1.25 Hz. Subjects then practiced syncopation at the same rate for four consecutive sessions. Post practice scans of the two coordination patterns were then performed. Before practice, baseline syncopation activated a much broader network of both cortical and subcortical regions than synchronization that included Supplementary Motor Area (SMA), bilateral putamen, left thalamus, bilateral superior temporal gyrus as well as the vermis. This pattern of activity is hypothesized to reflect the extra timing and attention requirements of syncopation. After practice, activity in superior temporal gyrus and vermis were no longer observed during syncopation reflecting a reduction in the need for attention and the use of sensory feedback for guiding behavior. Surprisingly, post practice synchronization resulted in additional significant activations in SMA, inferior frontal gyrus and superior temporal gyrus as well as small activations in bilateral putamen. Practice with the more difficult syncopation task thus had a dual effect of decreasing the number of active regions during syncopation and increasing the number of active regions during synchronization. Since overt syncopation performance did not change significantly as a result of practice, these observed neural changes appear to be due to context- and history-dependent factors, rather than behavioral learning per se.

  11. Benefits of Physical Activity

    MedlinePlus

    ... page from the NHLBI on Twitter. Benefits of Physical Activity Physical activity has many health benefits. These benefits ... of physical activity for your heart and lungs. Physical Activity Strengthens Your Heart and Improves Lung Function When ...

  12. Physical Activity and Cancer

    MedlinePlus

    ... can include working, exercising, performing household chores, and leisure-time activities such as walking, tennis, hiking, bicycling, ... active ( 4 ). A pooled analysis of data on leisure-time physical activity (activities done at an individual’s ...

  13. Increased anterior insula activity in anxious individuals is linked to diminished perceived control

    PubMed Central

    Alvarez, R P; Kirlic, N; Misaki, M; Bodurka, J; Rhudy, J L; Paulus, M P; Drevets, W C

    2015-01-01

    Individuals with high-trait anxiety frequently report decreased perceived control. However, it is unclear how these processes are instantiated at a neural level. Prior research suggests that individuals prone to anxiety may have exaggerated activity in the anterior insula and altered activity in the cingulate cortex during anticipation of aversive events. Thus, we hypothesized that anxiety proneness influences anterior insula activation during anticipation of unpredictable threat through decreased perceived control. Forty physically healthy adults underwent neuroimaging while they explored computer-simulated contexts associated either with or without the threat of an unpredictable shock. Skin conductance, anxiety ratings and blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging were used to assess responses to threat versus no threat. Perceived control was measured using the Anxiety Control Questionnaire-Revised. Mediation analysis examined how anxiety proneness influenced BOLD activity. Anticipation of unpredictable threat resulted in increased skin conductance responses, anxiety ratings and enhanced activation in bilateral insula, anterior midcingulate cortex (aMCC) and bed nucleus of the stria terminalis. Individuals with greater anxiety proneness and less perceived control showed greater activity in dorsal anterior insula (dAI). Perceived control mediated the relationship between anxiety proneness and dAI activity. Increased dAI activity was associated with increased activity in aMCC, which correlated with increased exploratory behavior. Results provide evidence that exaggerated insula activation during the threat of unpredictable shock is directly related to low perceived control in anxiety-prone individuals. Perceived control thus may constitute an important treatment target to modulate insula activity during anxious anticipation in anxiety-disordered individuals. PMID:26125154

  14. Physical Activity Is Linked to Greater Moment-To-Moment Variability in Spontaneous Brain Activity in Older Adults

    PubMed Central

    Burzynska, Agnieszka Z.; Wong, Chelsea N.; Voss, Michelle W.; Cooke, Gillian E.; Gothe, Neha P.; Fanning, Jason; McAuley, Edward; Kramer, Arthur F.

    2015-01-01

    Higher cardiorespiratory fitness (CRF) and physical activity (PA) in old age are associated with greater brain structural and functional integrity, and higher cognitive functioning. However, it is not known how different aspects of lifestyle such as sedentariness, light PA (LI-PA), or moderate-to-vigorous physical activity (MV-PA) relate to neural activity in aging. In addition, it is not known whether the effects of PA on brain function differ or overlap with those of CRF. Here, we objectively measured CRF as oxygen consumption during a maximal exercise test and measured PA with an accelerometer worn for 7 days in 100 healthy but low active older adults (aged 60–80 years). We modeled the relationships between CRF, PA, and brain functional integrity using multivariate partial least squares analysis. As an index of functional brain integrity we used spontaneous moment-to-moment variability in the blood oxygenation level-dependent signal (SDBOLD), known to be associated with better cognitive functioning in aging. We found that older adults who engaged more in LI-PA and MV-PA had greater SDBOLD in brain regions that play a role in integrating segregated functional domains in the brain and benefit from greater CRF or PA, such as precuneus, hippocampus, medial and lateral prefrontal, and temporal cortices. Our results suggest that engaging in higher intensity PA may have protective effects on neural processing in aging. Finally, we demonstrated that older adults with greater overall WM microstructure were those showing more LI-PA and MV-PA and greater SDBOLD. We conclude that SDBOLD is a promising correlate of functional brain health in aging. Future analyses will evaluate whether SDBOLD is modifiable with interventions aimed to increase PA and CRF in older adults. PMID:26244873

  15. Physical Activity Is Linked to Greater Moment-To-Moment Variability in Spontaneous Brain Activity in Older Adults.

    PubMed

    Burzynska, Agnieszka Z; Wong, Chelsea N; Voss, Michelle W; Cooke, Gillian E; Gothe, Neha P; Fanning, Jason; McAuley, Edward; Kramer, Arthur F

    2015-01-01

    Higher cardiorespiratory fitness (CRF) and physical activity (PA) in old age are associated with greater brain structural and functional integrity, and higher cognitive functioning. However, it is not known how different aspects of lifestyle such as sedentariness, light PA (LI-PA), or moderate-to-vigorous physical activity (MV-PA) relate to neural activity in aging. In addition, it is not known whether the effects of PA on brain function differ or overlap with those of CRF. Here, we objectively measured CRF as oxygen consumption during a maximal exercise test and measured PA with an accelerometer worn for 7 days in 100 healthy but low active older adults (aged 60-80 years). We modeled the relationships between CRF, PA, and brain functional integrity using multivariate partial least squares analysis. As an index of functional brain integrity we used spontaneous moment-to-moment variability in the blood oxygenation level-dependent signal (SDBOLD), known to be associated with better cognitive functioning in aging. We found that older adults who engaged more in LI-PA and MV-PA had greater SDBOLD in brain regions that play a role in integrating segregated functional domains in the brain and benefit from greater CRF or PA, such as precuneus, hippocampus, medial and lateral prefrontal, and temporal cortices. Our results suggest that engaging in higher intensity PA may have protective effects on neural processing in aging. Finally, we demonstrated that older adults with greater overall WM microstructure were those showing more LI-PA and MV-PA and greater SDBOLD. We conclude that SDBOLD is a promising correlate of functional brain health in aging. Future analyses will evaluate whether SDBOLD is modifiable with interventions aimed to increase PA and CRF in older adults.

  16. Brain oscillatory activity during motor imagery in EEG-fMRI coregistration.

    PubMed

    Formaggio, Emanuela; Storti, Silvia Francesca; Cerini, Roberto; Fiaschi, Antonio; Manganotti, Paolo

    2010-12-01

    The purpose of the present work was to investigate the correlation between topographical changes in brain oscillatory activity and the blood oxygenation level-dependent (BOLD) signal during a motor imagery (MI) task using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) coregistration. EEG was recorded in 7 healthy subjects inside a 1.5 T MR scanner during the imagination of the kinesthetic experience of movement. A Fast Fourier Transform was applied to EEG signal in the rest and active conditions. We used the event-related-synchronization (ERS)/desynchronization (ERD) approach to characterize where the imagination of movement produces a decrease in alpha and beta power. The mean alpha map showed ERD decrease localized over the contralateral sensory motor area (SM1c) and a light desynchronization in the ipsilateral sensory motor area (SM1i); whereas the mean beta map showed ERD decrease over the supplementary motor area (SMA). fMRI showed significant activation in SMA, SM1c, SM1i. The correlation is negative in the contralateral side and positive in the ipsilateral side. Using combined EEG-fMRI signals we obtained useful new information on the description of the changes in oscillatory activity in alpha and beta bands during MI and on the investigation of the sites of BOLD activity as possible sources in generating these rhythms. By correlating BOLD and ERD/ERS we may identify more accurately which regions contribute to changes of the electrical response.

  17. Cortical connective field estimates from resting state fMRI activity

    PubMed Central

    Gravel, Nicolás; Harvey, Ben; Nordhjem, Barbara; Haak, Koen V.; Dumoulin, Serge O.; Renken, Remco; Ćurčić-Blake, Branislava; Cornelissen, Frans W.

    2014-01-01

    One way to study connectivity in visual cortical areas is by examining spontaneous neural activity. In the absence of visual input, such activity remains shaped by the underlying neural architecture and, presumably, may still reflect visuotopic organization. Here, we applied population connective field (CF) modeling to estimate the spatial profile of functional connectivity in the early visual cortex during resting state functional magnetic resonance imaging (RS-fMRI). This model-based analysis estimates the spatial integration between blood-oxygen level dependent (BOLD) signals in distinct cortical visual field maps using fMRI. Just as population receptive field (pRF) mapping predicts the collective neural activity in a voxel as a function of response selectivity to stimulus position in visual space, CF modeling predicts the activity of voxels in one visual area as a function of the aggregate activity in voxels in another visual area. In combination with pRF mapping, CF locations on the cortical surface can be interpreted in visual space, thus enabling reconstruction of visuotopic maps from resting state data. We demonstrate that V1 ➤ V2 and V1 ➤ V3 CF maps estimated from resting state fMRI data show visuotopic organization. Therefore, we conclude that—despite some variability in CF estimates between RS scans—neural properties such as CF maps and CF size can be derived from resting state data. PMID:25400541

  18. Cortical connective field estimates from resting state fMRI activity.

    PubMed

    Gravel, Nicolás; Harvey, Ben; Nordhjem, Barbara; Haak, Koen V; Dumoulin, Serge O; Renken, Remco; Curčić-Blake, Branislava; Cornelissen, Frans W

    2014-01-01

    One way to study connectivity in visual cortical areas is by examining spontaneous neural activity. In the absence of visual input, such activity remains shaped by the underlying neural architecture and, presumably, may still reflect visuotopic organization. Here, we applied population connective field (CF) modeling to estimate the spatial profile of functional connectivity in the early visual cortex during resting state functional magnetic resonance imaging (RS-fMRI). This model-based analysis estimates the spatial integration between blood-oxygen level dependent (BOLD) signals in distinct cortical visual field maps using fMRI. Just as population receptive field (pRF) mapping predicts the collective neural activity in a voxel as a function of response selectivity to stimulus position in visual space, CF modeling predicts the activity of voxels in one visual area as a function of the aggregate activity in voxels in another visual area. In combination with pRF mapping, CF locations on the cortical surface can be interpreted in visual space, thus enabling reconstruction of visuotopic maps from resting state data. We demonstrate that V1 ➤ V2 and V1 ➤ V3 CF maps estimated from resting state fMRI data show visuotopic organization. Therefore, we conclude that-despite some variability in CF estimates between RS scans-neural properties such as CF maps and CF size can be derived from resting state data.

  19. Effect of median-nerve electrical stimulation on BOLD activity in acute ischemic stroke patients.

    PubMed

    Manganotti, P; Storti, S F; Formaggio, E; Acler, M; Zoccatelli, G; Pizzini, F B; Alessandrini, F; Bertoldo, A; Toffolo, G M; Bovi, P; Beltramello, A; Moretto, G; Fiaschi, A

    2012-01-01

    To investigate blood oxygenation level-dependent (BOLD) activation during somatosensory electrical stimulation of the median nerve in acute stroke patients and to determine its correlation with ischemic damage and clinical recovery over time. Fourteen acute stroke patients underwent functional magnetic resonance imaging (fMRI) during contralesional median-nerve electrical stimulation 12-48 h after stroke. Findings were then validated by diffusion tensor imaging (DTI) and motor evoked potential by transcranial magnetic stimulation (TMS). Poor clinical recovery at three months was noted in four patients with no activation in the early days after stroke, whereas good clinical recovery was observed in eight patients with a normal activation pattern in the primary sensory motor area in the acute phase. In two patients BOLD activation correlated weakly with clinical recovery. Findings from TMS and DTI partially correlated with clinical recovery and functional scores. Clinically relevant insights into the "functional reserve" of stroke patients gained with peripheral nerve stimulation during fMRI may carry prognostic value already in the acute period of a cerebrovascular accident. BOLD activation maps could provide insights into the functional organization of the residual systems and could contribute to medical decision making in neurological and rehabilitative treatment. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  20. Storm in a coffee cup: caffeine modifies brain activation to social signals of threat.

    PubMed

    Smith, Jessica E; Lawrence, Andrew D; Diukova, Ana; Wise, Richard G; Rogers, Peter J

    2012-10-01

    Caffeine, an adenosine A₁ and A(2A) receptor antagonist, is the most popular psychostimulant drug in the world, but it is also anxiogenic. The neural correlates of caffeine-induced anxiety are currently unknown. This study investigated the effects of caffeine on brain regions implicated in social threat processing and anxiety. Participants were 14 healthy male non/infrequent caffeine consumers. In a double-blind placebo-controlled crossover design, they underwent blood oxygenation level-dependent functional magnetic resonance imaging (fMRI) while performing an emotional face processing task 1 h after receiving caffeine (250 mg) or placebo in two fMRI sessions (counterbalanced, 1-week washout). They rated anxiety and mental alertness, and their blood pressure was measured, before and 2 h after treatment. Results showed that caffeine induced threat-related (angry/fearful faces > happy faces) midbrain-periaqueductal gray activation and abolished threat-related medial prefrontal cortex wall activation. Effects of caffeine on extent of threat-related amygdala activation correlated negatively with level of dietary caffeine intake. In concurrence with these changes in threat-related brain activation, caffeine increased self-rated anxiety and diastolic blood pressure. Caffeine did not affect primary visual cortex activation. These results are the first to demonstrate potential neural correlates of the anxiogenic effect of caffeine, and they implicate the amygdala as a key site for caffeine tolerance.

  1. Effects of anesthesia on BOLD signal and neuronal activity in the somatosensory cortex

    PubMed Central

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

    2015-01-01

    Most functional magnetic resonance imaging (fMRI) animal studies rely on anesthesia, which can induce a variety of drug-dependent physiological changes, including depression of neuronal activity and cerebral metabolism as well as direct effects on the vasculature. The goal of this study was to characterize the effects of anesthesia on the BOLD signal and neuronal activity. Simultaneous fMRI and electrophysiology were used to measure changes in single units (SU), multi-unit activity (MUA), local field potentials (LFP), and the blood oxygenation level-dependent (BOLD) response in the somatosensory cortex during whisker stimulation of rabbits before, during and after anesthesia with fentanyl or isoflurane. Our results indicate that anesthesia modulates the BOLD signal as well as both baseline and stimulus-evoked neuronal activity, and, most significantly, that the relationship between the BOLD and electrophysiological signals depends on the type of anesthetic. Specifically, the behavior of LFP observed under isoflurane did not parallel the behavior of BOLD, SU, or MUA. These findings suggest that the relationship between these signals may not be straightforward. BOLD may scale more closely with the best measure of the excitatory subcomponents of the underlying neuronal activity, which may vary according to experimental conditions that alter the excitatory/inhibitory balance in the cortex. PMID:26104288

  2. Brain activation associated with motor imagery of coordination exercises and social abilities.

    PubMed

    Mochizuki, Akito Azumane; Sudo, Michiko Mochizuki; Kirino, Eiji; Itoh, Kenji

    2014-01-01

    The purposes of the present study were: (1) to investigate the brain activation associated with coordination exercises done by one person and those by two persons and (2) to examine the interrelationships between the brain activation and social abilities. We were interested in testing the hypothesis that viewing two-person coordination exercises evokes more sophisticated brain activation than viewing one-person coordination exercises. Thirty Japanese college students served as subjects. There were two sessions in this study: the functional magnetic resonance imaging (fMRI) session and the social ability session. In the fMRI session, the subjects were instructed to imagine they were performing coordination exercises. Also, we examined the social abilities from the viewpoint of empathising. Empathising was measured by self-reports on the Systemising, Empathy and Autism Spectrum Quotients (SQ, EQ and AQ). Regarding brain activation, blood oxygenation level dependent (BOLD) activation was significant in specific areas such as the left cuneus (Brodmann area: BA 17) when the subjects imagined they were performing exercises involving two persons, as compared with the cases when they imagined they were performing exercises involving only one person. The fMRI results showed that exercises done by two persons require more sophisticated communication than those done by one person. Furthermore, the results of this study suggested that those with more autistic traits may undergo difficulties in the exercises done by two persons, especially in the case of playing a role as a follower.

  3. Joint maximum likelihood estimation of activation and Hemodynamic Response Function for fMRI.

    PubMed

    Bazargani, Negar; Nosratinia, Aria

    2014-07-01

    Blood Oxygen Level Dependent (BOLD) functional magnetic resonance imaging (fMRI) maps the brain activity by measuring blood oxygenation level, which is related to brain activity via a temporal impulse response function known as the Hemodynamic Response Function (HRF). The HRF varies from subject to subject and within areas of the brain, therefore a knowledge of HRF is necessary for accurately computing voxel activations. Conversely a knowledge of active voxels is highly beneficial for estimating the HRF. This work presents a joint maximum likelihood estimation of HRF and activation based on low-rank matrix approximations operating on regions of interest (ROI). Since each ROI has limited data, a smoothing constraint on the HRF is employed via Tikhonov regularization. The method is analyzed under both white noise and colored noise. Experiments with synthetic data show that accurate estimation of the HRF is possible with this method without prior assumptions on the exact shape of the HRF. Further experiments involving real fMRI experiments with auditory stimuli are used to validate the proposed method.

  4. Increased Intrinsic Brain Activity in the Striatum Reflects Symptom Dimensions in Schizophrenia

    PubMed Central

    Sorg, Christian; Manoliu, Andrei; Neufang, Susanne; Myers, Nicholas; Peters, Henning; Schwerthöffer, Dirk; Scherr, Martin; Mühlau, Mark; Zimmer, Claus; Drzezga, Alexander; Förstl, Hans; Bäuml, Josef; Eichele, Tom; Wohlschläger, Afra M.; Riedl, Valentin

    2013-01-01

    Striatal dysfunction is thought to be a fundamental element in schizophrenia. Striatal dopamine dysfunction impacts on reward processing and learning and is present even at rest. Here, we addressed the question whether and how spontaneous neuronal activity in the striatum is altered in schizophrenia. We therefore assessed intrinsic striatal activity and its relation with disorder states and symptom dimensions in patients with schizophrenia. We performed resting-state functional (rs-fMRI) and structural magnetic resonance imaging as well as psychometric assessment in 21 schizophrenic patients during psychosis. On average 9 months later, we acquired follow-up data during psychotic remission and with comparable levels of antipsychotic medication. Twenty-one age- and sex-matched healthy controls were included in the study. Independent component analysis of fMRI data yielded spatial maps and time-courses of coherent ongoing blood-oxygen-level-dependent signal fluctuations, which were used for group comparisons and correlation analyses with scores of the positive and negative syndrome scale. During psychosis, coherent intrinsic activity of the striatum was increased in the dorsal part and correlated with positive symptoms such as delusion and hallucination. In psychotic remission of the same patients, activity of the ventral striatum was increased and correlated with negative symptoms such as emotional withdrawal and blunted affect. Results were controlled for volumetric and medication effects. These data provide first evidence that in schizophrenia intrinsic activity is changed in the striatum and corresponds to disorder states and symptom dimensions. PMID:22241165

  5. Storm in a coffee cup: caffeine modifies brain activation to social signals of threat

    PubMed Central

    Lawrence, Andrew D.; Diukova, Ana; Wise, Richard G.; Rogers, Peter J.

    2012-01-01

    Caffeine, an adenosine A1 and A2A receptor antagonist, is the most popular psychostimulant drug in the world, but it is also anxiogenic. The neural correlates of caffeine-induced anxiety are currently unknown. This study investigated the effects of caffeine on brain regions implicated in social threat processing and anxiety. Participants were 14 healthy male non/infrequent caffeine consumers. In a double-blind placebo-controlled crossover design, they underwent blood oxygenation level-dependent functional magnetic resonance imaging (fMRI) while performing an emotional face processing task 1 h after receiving caffeine (250 mg) or placebo in two fMRI sessions (counterbalanced, 1-week washout). They rated anxiety and mental alertness, and their blood pressure was measured, before and 2 h after treatment. Results showed that caffeine induced threat-related (angry/fearful faces > happy faces) midbrain-periaqueductal gray activation and abolished threat-related medial prefrontal cortex wall activation. Effects of caffeine on extent of threat-related amygdala activation correlated negatively with level of dietary caffeine intake. In concurrence with these changes in threat-related brain activation, caffeine increased self-rated anxiety and diastolic blood pressure. Caffeine did not affect primary visual cortex activation. These results are the first to demonstrate potential neural correlates of the anxiogenic effect of caffeine, and they implicate the amygdala as a key site for caffeine tolerance. PMID:21972425

  6. Differential brain activity in alcoholics and social drinkers to alcohol cues: relationship to craving.

    PubMed

    Myrick, Hugh; Anton, Raymond F; Li, Xingbao; Henderson, Scott; Drobes, David; Voronin, Konstantin; George, Mark S

    2004-02-01

    Using fMRI, our group previously found that after a sip of alcohol and exposure to alcohol beverage pictures, alcoholics compared to social drinkers had increased differential brain activity in the prefrontal cortex and anterior thalamus. This study extends this earlier work with several improvements including imaging the entire brain (rather than the anterior half previously) and recording craving, while the subjects viewed images within the scanner. In a Philips 1.5 T MRI scanner, 10 nontreatment-seeking alcoholics and 10 age-matched healthy social drinkers were given a sip of alcohol before viewing a 12 min randomized presentation of pictures of alcoholic beverages, nonalcoholic beverages, and two different visual control tasks. During picture presentation, changes in regional brain activity were measured in 15 transverse T2(*)-weighted blood oxygen level dependent slices. Subjects rated their urge to drink after each picture sequence. After a sip of alcohol, while viewing alcohol cues compared to viewing other beverage cues, the alcoholics, but not social drinkers, reported higher craving ratings and had increased activity in the prefrontal cortex and anterior limbic regions. Brain activity in the left nucleus accumbens, anterior cingulate, and left orbitofrontal cortex significantly correlated with subjective craving ratings in alcohol subjects but not in control subjects. This study suggests, as did our earlier study, that alcoholics and not social drinkers, when exposed to alcohol cues, have increased brain activity in areas that reportedly subserve craving for other addictive substances.

  7. Do brain activation changes persist in athletes with a history of multiple concussions who are asymptomatic?

    PubMed

    Elbin, R J; Covassin, Tracey; Hakun, Jonathan; Kontos, Anthony P; Berger, Kevin; Pfeiffer, Karin; Ravizza, Susan

    2012-01-01

    To evaluate brain activation patterns of asymptomatic athletes with a history of two or more concussions. A paired case-control design was used to evaluate brain activation patterns during cognitive performance in 14 athletes with a history of two or more concussions and 14 age- and sex-matched controls with no previous concussion. Percentage Blood-Oxygen-Level-Dependent (BOLD) change during an N-back working memory task was assessed in all participants. Performance on the Trail-Making Test Form A and B, Symbol-Digit Modalities Test and the Immediate Post-concussion Assessment and Cognitive Test (ImPACT) was also compared between groups. As expected, brain regions activated during the performance of the N-back were equivalent between groups. The groups performed similarly on the neurocognitive measures. The history of concussion group was less accurate than controls on the 1-, 2- and 3-back conditions of the N-back. Following the complete resolution of symptoms, a history of two or more concussions is not associated with changes in regional brain activation during the performance of working memory task. Compensatory brain activation may only persist during the typically brief time athletes experience symptoms following concussion.

  8. Activation of suprachiasmatic nuclei and primary visual cortex depends upon time of day.

    PubMed

    Vimal, Ram L P; Pandey-Vimal, Manju-Uma C; Vimal, Love-Shyam P; Frederick, Blaise B; Stopa, Edward G; Renshaw, Perry F; Vimal, Shalini P; Harper, David G

    2009-01-01

    The human suprachiasmatic nucleus (SCN), the master biological clock, is a small (approximately 2 mm(3)) and deep structure located in the anterior hypothalamus. Previous methods do not allow in vivo study of the human SCN in a non-invasive manner. Therefore, we explored blood oxygen level-dependent (BOLD)-functional magnetic resonance imaging (fMRI) with OFF-ON-OFF block-designed visual stimuli to record the activities in the 'SCN and peri SCN in the anterior hypothalamus' (SCN+) and the primary visual area V1 using a 3T Siemens scanner and six normal subjects. We found that: (i) the BOLD-fMRI response to light and the mean of percentage activation in the SCN+ at midday was significantly less than that at night; and (ii) the number of activated voxels in most of the visual area V1 at midday was significantly higher than that at night. We conclude that BOLD-fMRI responses to light in the SCN+ and the V1 areas vary with time of day. This conclusion is consistent with: (i) the previously measured phase-response curve to light [J. Physiol., 549.3 (2003) 945] for the SCN activity at critical intensity threshold; and (ii) the interaction of the melanopsin-based signals with the rod-cone signals at the 'giant' retinal ganglion cells [Nature, 433 (2005) 749] for the V1 activity.

  9. Does functional MRI detect activation in white matter? A review of emerging evidence, issues, and future directions

    PubMed Central

    Gawryluk, Jodie R.; Mazerolle, Erin L.; D'Arcy, Ryan C. N.

    2014-01-01

    Functional magnetic resonance imaging (fMRI) is a non-invasive technique that allows for visualization of activated brain regions. Until recently, fMRI studies have focused on gray matter. There are two main reasons white matter fMRI remains controversial: (1) the blood oxygen level dependent (BOLD) fMRI signal depends on cerebral blood flow and volume, which are lower in white matter than gray matter and (2) fMRI signal has been associated with post-synaptic potentials (mainly localized in gray matter) as opposed to action potentials (the primary type of neural activity in white matter). Despite these observations, there is no direct evidence against measuring fMRI activation in white matter and reports of fMRI activation in white matter continue to increase. The questions underlying white matter fMRI activation are important. White matter fMRI activation has the potential to greatly expand the breadth of brain connectivity research, as well as improve the assessment and diagnosis of white matter and connectivity disorders. The current review provides an overview of the motivation to investigate white matter fMRI activation, as well as the published evidence of this phenomenon. We speculate on possible neurophysiologic bases of white matter fMRI signals, and discuss potential explanations for why reports of white matter fMRI activation are relatively scarce. We end with a discussion of future basic and clinical research directions in the study of white matter fMRI. PMID:25152709

  10. Tuning electrocatalytic activity of Pt monolayer shell by bimetallic Ir-M (M=Fe, Co, Ni or Cu) cores for the oxygen reduction reaction

    SciTech Connect

    Kuttiyiel, Kurian A.; Choi, YongMan; Sasaki, Kotaro; Su, Dong; Hwang, Sun -Mi; Yim, Sung -Dae; Yang, Tae -Hyun; Park, Gu -Gon; Adzic, Radoslav R.

    2016-05-18

    Here, platinum monolayer electrocatalyst are known to exhibit excellent oxygen reduction reaction (ORR) activity depending on the type of substrate used. Here we demonstrate a relationship between the ORR electrocatalytic activity and the surface electronic structure of Pt monolayer shell induced by various IrM bimetallic cores (M=Fe, Co, Ni or Cu). The relationship is rationalized by comparing density functional theory calculations and experimental results. For an efficient Pt monolayer electrocatalyst, the core should induce sufficient contraction to the Pt shell leading to a downshift of the d-band center with respect to the Fermi level. Depending on the structure of the IrM, relative to that of pure Ir, this interaction not only alters the electronic and geometric structure but also induces segregation effects. Combined these effects significantly enhance the ORR activities of the Pt monolayer shell on bimetallic Ir cores electrocatalysts.

  11. Tuning electrocatalytic activity of Pt monolayer shell by bimetallic Ir-M (M=Fe, Co, Ni or Cu) cores for the oxygen reduction reaction

    SciTech Connect

    Kuttiyiel, Kurian A.; Choi, YongMan; Sasaki, Kotaro; Su, Dong; Hwang, Sun -Mi; Yim, Sung -Dae; Yang, Tae -Hyun; Park, Gu -Gon; Adzic, Radoslav R.

    2016-05-18

    Here, platinum monolayer electrocatalyst are known to exhibit excellent oxygen reduction reaction (ORR) activity depending on the type of substrate used. Here we demonstrate a relationship between the ORR electrocatalytic activity and the surface electronic structure of Pt monolayer shell induced by various IrM bimetallic cores (M=Fe, Co, Ni or Cu). The relationship is rationalized by comparing density functional theory calculations and experimental results. For an efficient Pt monolayer electrocatalyst, the core should induce sufficient contraction to the Pt shell leading to a downshift of the d-band center with respect to the Fermi level. Depending on the structure of the IrM, relative to that of pure Ir, this interaction not only alters the electronic and geometric structure but also induces segregation effects. Combined these effects significantly enhance the ORR activities of the Pt monolayer shell on bimetallic Ir cores electrocatalysts.

  12. Tuning electrocatalytic activity of Pt monolayer shell by bimetallic Ir-M (M=Fe, Co, Ni or Cu) cores for the oxygen reduction reaction

    DOE PAGES

    Kuttiyiel, Kurian A.; Choi, YongMan; Sasaki, Kotaro; ...

    2016-05-18

    Here, platinum monolayer electrocatalyst are known to exhibit excellent oxygen reduction reaction (ORR) activity depending on the type of substrate used. Here we demonstrate a relationship between the ORR electrocatalytic activity and the surface electronic structure of Pt monolayer shell induced by various IrM bimetallic cores (M=Fe, Co, Ni or Cu). The relationship is rationalized by comparing density functional theory calculations and experimental results. For an efficient Pt monolayer electrocatalyst, the core should induce sufficient contraction to the Pt shell leading to a downshift of the d-band center with respect to the Fermi level. Depending on the structure of themore » IrM, relative to that of pure Ir, this interaction not only alters the electronic and geometric structure but also induces segregation effects. Combined these effects significantly enhance the ORR activities of the Pt monolayer shell on bimetallic Ir cores electrocatalysts.« less

  13. EEG-correlated fMRI of human alpha activity.

    PubMed

    Laufs, H; Kleinschmidt, A; Beyerle, A; Eger, E; Salek-Haddadi, A; Preibisch, C; Krakow, K

    2003-08-01

    Electroencephalography-correlated functional magnetic resonance imaging (EEG/fMRI) can be used to identify blood oxygen level-dependent (BOLD) signal changes associated with both physiological and pathological EEG events. Here, we implemented continuous and simultaneous EEG/fMRI to identify BOLD signal changes related to spontaneous power fluctuations in the alpha rhythm (8-12 Hz), the dominant EEG pattern during relaxed wakefulness. Thirty-two channels of EEG were recorded in 10 subjects during eyes-closed rest inside a 1.5-T magnet resonance (MR) scanner using an MR-compatible EEG recording system. Functional scanning by echoplanar imaging covered almost the entire cerebrum every 4 s. Off-line MRI artifact subtraction software was applied to obtain continuous EEG data during fMRI acquisition. The average alpha power over 1-s epochs was derived at several electrode positions using a Fast Fourier Transform. The power time course was then convolved with a canonical hemodynamic response function, down-sampled, and used for statistical parametric mapping of associated signal changes in the image time series. At all electrode positions studied, a strong negative correlation of parietal and frontal cortical activity with alpha power was found. Conversely, only sparse and nonsystematic positive correlation was detected. The relevance of these findings is discussed in view of the current theories on the generation and significance of the alpha rhythm and the related functional neuroimaging findings.

  14. Adolescent sexual activity.

    PubMed

    Braverman, P K; Strasburger, V C

    1993-11-01

    Adolescents are becoming sexually active at younger ages. One half of the adolescents in the United States are sexually active. This article reviews adolescent sexual activity, including rates of sexual activity, sexual practices, gay and lesbian youth, and factors affecting the initiation of sexual activity. In addition, adolescent pregnancy, with possible outcomes and effects on teen parents and their offspring, is discussed.

  15. A functional polymorphism of the MAOA gene modulates spontaneous brain activity in pons.

    PubMed

    Lei, Hui; Zhang, Xiaocui; Di, Xin; Rao, Hengyi; Ming, Qingsen; Zhang, Jibiao; Guo, Xiao; Jiang, Yali; Gao, Yidian; Yi, Jinyao; Zhu, Xiongzhao; Yao, Shuqiao

    2014-01-01

    To investigate the effects of a functional polymorphism of the monoamine oxidase A (MAOA) gene on spontaneous brain activity in healthy male adolescents. Thirty-one healthy male adolescents with the low-activity MAOA genotype (MAOA-L) and 25 healthy male adolescents with the high-activity MAOA genotype (MAOA-H) completed the 11-item Barratt Impulsiveness Scale (BIS-11) questionnaire and were subjected to resting-state functional magnetic resonance imaging (rs-fMRI) scans. The amplitude of low-frequency fluctuation (ALFF) of the blood oxygen level-dependent (BOLD) signal was calculated using REST software. ALFF data were related to BIS scores and compared between genotype groups. Compared with the MAOA-H group, the MAOA-L group showed significantly lower ALFFs in the pons. There was a significant correlation between the BIS scores and the ALFF values in the pons for MAOA-L group, but not for the MAOA-H group. Further regression analysis showed a significant genotype by ALFF values interaction effect on BIS scores. Lower spontaneous brain activity in the pons of the MAOA-L male adolescents may provide a neural mechanism by which boys with the MAOA-L genotype confers risk for impulsivity and aggression.

  16. A Functional Polymorphism of the MAOA Gene Modulates Spontaneous Brain Activity in Pons

    PubMed Central

    Lei, Hui; Zhang, Xiaocui; Di, Xin; Rao, Hengyi; Ming, Qingsen; Zhang, Jibiao; Guo, Xiao; Jiang, Yali; Gao, Yidian; Yi, Jinyao; Zhu, Xiongzhao; Yao, Shuqiao

    2014-01-01

    Objective. To investigate the effects of a functional polymorphism of the monoamine oxidase A (MAOA) gene on spontaneous brain activity in healthy male adolescents. Methods. Thirty-one healthy male adolescents with the low-activity MAOA genotype (MAOA-L) and 25 healthy male adolescents with the high-activity MAOA genotype (MAOA-H) completed the 11-item Barratt Impulsiveness Scale (BIS-11) questionnaire and were subjected to resting-state functional magnetic resonance imaging (rs-fMRI) scans. The amplitude of low-frequency fluctuation (ALFF) of the blood oxygen level-dependent (BOLD) signal was calculated using REST software. ALFF data were related to BIS scores and compared between genotype groups. Results. Compared with the MAOA-H group, the MAOA-L group showed significantly lower ALFFs in the pons. There was a significant correlation between the BIS scores and the ALFF values in the pons for MAOA-L group, but not for the MAOA-H group. Further regression analysis showed a significant genotype by ALFF values interaction effect on BIS scores. Conclusions. Lower spontaneous brain activity in the pons of the MAOA-L male adolescents may provide a neural mechanism by which boys with the MAOA-L genotype confers risk for impulsivity and aggression. PMID:24971323

  17. Functional connectivity and activity of white matter in somatosensory pathways under tactile stimulations.

    PubMed

    Wu, Xi; Yang, Zhipeng; Bailey, Stephen K; Zhou, Jiliu; Cutting, Laurie E; Gore, John C; Ding, Zhaohua

    2017-03-08

    Functional MRI has proven to be effective in detecting neural activity in brain cortices on the basis of blood oxygenation level dependent (BOLD) contrast, but has relatively poor sensitivity for detecting neural activity in white matter. To demonstrate that BOLD signals in white matter are detectable and contain information on neural activity, we stimulated the somatosensory system and examined distributions of BOLD signals in related white matter pathways. The temporal correlation profiles and frequency contents of BOLD signals were compared between stimulation and resting conditions, and between relevant white matter fibers and background regions, as well as between left and right side stimulations. Quantitative analyses show that, overall, MR signals from white matter fiber bundles in the somatosensory system exhibited significantly greater temporal correlations with the primary sensory cortex and greater signal power during tactile stimulations than in a resting state, and were stronger than corresponding measurements for background white matter both during stimulations and in a resting state. The temporal correlation and signal power under stimulation were found to be twice those observed from the same bundle in a resting state, and bore clear relations with the side of stimuli. These indicate that BOLD signals in white matter fibers encode neural activity related to their functional roles connecting cortical volumes, which are detectable with appropriate methods.

  18. Right hemisphere neural activations in the recall of waking fantasies and of dreams.

    PubMed

    Benedetti, Francesco; Poletti, Sara; Radaelli, Daniele; Ranieri, Rebecca; Genduso, Valeria; Cavallotti, Simone; Castelnovo, Anna; Smeraldi, Enrico; Scarone, Silvio; D'Agostino, Armando

    2015-10-01

    The story-like organization of dreams is characterized by a pervasive bizarreness of events and actions that resembles psychotic thought, and largely exceeds that observed in normal waking fantasies. Little is known about the neural correlates of the confabulatory narrative construction of dreams. In this study, dreams, fantasies elicited by ambiguous pictorial stimuli, and non-imaginative first- and third-person narratives from healthy participants were recorded, and were then studied for brain blood oxygen level-dependent functional magnetic resonance imaging on a 3.0-Tesla scanner while listening to their own narrative reports and attempting a retrieval of the corresponding experience. In respect to non-bizarre reports of daytime activities, the script-driven recall of dreams and fantasies differentially activated a right hemisphere network including areas in the inferior frontal gyrus, and superior and middle temporal gyrus. Neural responses were significantly greater for fantasies than for dreams in all regions, and inversely proportional to the degree of bizarreness observed in narrative reports. The inferior frontal gyrus, superior and middle temporal gyrus have been implicated in the semantic activation, integration and selection needed to build a coherent story representation and to resolve semantic ambiguities; in deductive and inferential reasoning; in self- and other-perspective taking, theory of mind, moral and autobiographical reasoning. Their degree of activation could parallel the level of logical robustness or inconsistency experienced when integrating information and mental representations in the process of building fantasy and dream narratives.

  19. Preference for immediate over delayed rewards is associated with magnitude of ventral striatal activity.

    PubMed

    Hariri, Ahmad R; Brown, Sarah M; Williamson, Douglas E; Flory, Janine D; de Wit, Harriet; Manuck, Stephen B

    2006-12-20

    Discounting future outcomes as a function of their deferred availability underlies much of human decision making. Discounting, or preference for immediate over delayed rewards of larger value, is often associated with impulsivity and is a risk factor for addictive disorders such as pathological gambling, cigarette smoking, and drug and alcohol abuse. The ventral striatum (VS) is involved in mediating behavioral responses and physiological states associated with reward, and dysregulation of the VS contributes to addiction, perhaps by affecting impulsive decision-making. Behavioral tests of delay discounting (DD), which index preference for smaller immediate over larger delayed rewards, covary with impulsive tendencies in humans. In the current study, we examined the relationship between individual differences in DD, measured in a behavioral assessment, and VS activity measured with blood oxygenation level-dependent functional magnetic resonance imaging, in 45 adult volunteers. VS activity was determined using a task involving positive and negative feedback with monetary reward. Analyses revealed that individual differences in DD correlate positively with magnitude of VS activation in response to both positive and negative feedback, compared with a no-feedback control condition. Variability in DD was also associated with differential VS activation in response to positive, compared with negative, feedback. Collectively, our results suggest that increased preference for smaller immediate over larger delayed rewards reflects both a relatively indiscriminate and hyper-reactive VS circuitry. They also highlight a specific neurocognitive mechanism that may contribute to increased risk for addiction.

  20. Top-down regulation of default mode activity in spatial visual attention

    PubMed Central

    Wen, Xiaotong; Liu, Yijun; Yao, Li; Ding, Mingzhou

    2013-01-01

    Dorsal anterior cingulate and bilateral anterior insula form a task control network (TCN) whose primary function includes initiating and maintaining task-level cognitive set and exerting top-down regulation of sensorimotor processing. The default mode network (DMN), comprising an anatomically distinct set of cortical areas, mediates introspection and self-referential processes. Resting-state data show that TCN and DMN interact. The functional ramifications of their interaction remain elusive. Recording fMRI data from human subjects performing a visual spatial attention task and correlating Granger causal influences with behavioral performance and blood-oxygen-level-dependent (BOLD) activity we report three main findings. First, causal influences from TCN to DMN, i.e., TCN→DMN, are positively correlated with behavioral performance. Second, causal influences from DMN to TCN, i.e., DMN→TCN, are negatively correlated with behavioral performance. Third, stronger DMN→TCN are associated with less elevated BOLD activity in TCN, whereas the relationship between TCN→DMN and DMN BOLD activity is unsystematic. These results suggest that during visual spatial attention, top-down signals from TCN to DMN regulate the activity in DMN to enhance behavioral performance, whereas signals from DMN to TCN, acting possibly as internal noise, interfere with task control, leading to degraded behavioral performance. PMID:23575842

  1. Total phenolic content and antioxidant activity of myrtle (Myrtus communis) extracts.

    PubMed

    Amensour, Mahassine; Sendra, Esther; Abrini, Jamal; Bouhdid, Samira; Pérez-Alvarez, José Angel; Fernández-López, Juana

    2009-06-01

    The total phenolic content and antioxidant activity of methanolic, ethanolic and aqueous extracts of myrtle (Myrtus communis) leaves and berries were measured to find new potential sources of natural antioxidants. Total phenolic content was assessed by the Folin-Ciocalteau assay, while the antioxidant activity was evaluated by three methods: diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, the reducing antioxidant power assay and beta-carotene linoleic acid assay. The total phenol content of myrtle extracts ranged between 9.0 and 35.6 mg GAE per g extract. For each solvent, leaf extracts contained significantly higher amount of total phenolic compounds than berry extracts. All of the extracts presented antioxidant capacity assessed by the three methods, but at different levels depending on the concentration, the extraction solvent and the part of the plant used. Generally, leaf extracts showed higher antioxidant activities than berry extracts, while the overall antioxidant strength was in the order methanol > water > ethanol in leaf extracts and methanol > ethanol > water in berry extracts. The phenolic content exhibited a positive correlation with the antioxidant activity: DPPH assay showed the highest correlation (r = 0.949), followed by the reducing power assay (r = 0.914) and the lowest for the beta-carotene linoleic acid assay (r = 0.722).

  2. Areas of brain activation in males and females during viewing of erotic film excerpts.

    PubMed

    Karama, Sherif; Lecours, André Roch; Leroux, Jean-Maxime; Bourgouin, Pierre; Beaudoin, Gilles; Joubert, Sven; Beauregard, Mario

    2002-05-01

    Various lines of evidence indicate that men generally experience greater sexual arousal (SA) to erotic stimuli than women. Yet, little is known regarding the neurobiological processes underlying such a gender difference. To investigate this issue, functional magnetic resonance imaging was used to compare the neural correlates of SA in 20 male and 20 female subjects. Brain activity was measured while male and female subjects were viewing erotic film excerpts. Results showed that the level of perceived SA was significantly higher in male than in female subjects. When compared to viewing emotionally neutral film excerpts, viewing erotic film excerpts was associated, for both genders, with bilateral blood oxygen level dependent (BOLD) signal increases in the anterior cingulate, medial prefrontal, orbitofrontal, insular, and occipitotemporal cortices, as well as in the amygdala and the ventral striatum. Only for the group of male subjects was there evidence of a significant activation of the thalamus and hypothalamus, a sexually dimorphic area of the brain known to play a pivotal role in physiological arousal and sexual behavior. When directly compared between genders, hypothalamic activation was found to be significantly greater in male subjects. Furthermore, for male subjects only, the magnitude of hypothalamic activation was positively correlated with reported levels of SA. These findings reveal the existence of similarities and dissimilarities in the way the brain of both genders responds to erotic stimuli. They further suggest that the greater SA generally experienced by men, when viewing erotica, may be related to the functional gender difference found here with respect to the hypothalamus.

  3. Relationship between impulsivity, prefrontal anticipatory activation, and striatal dopamine release during rewarded task performance

    PubMed Central

    Weiland, Barbara J.; Heitzeg, Mary M.; Zald, David; Cummiford, Chelsea; Love, Tiffany; Zucker, Robert A.; Zubieta, Jon-Kar

    2014-01-01

    Impulsivity, and in particular the negative urgency aspect of this trait, is associated with poor inhibitory control when experiencing negative emotion. Individual differences in aspects of impulsivity have been correlated with striatal dopamine D2/D3 receptor availability and function. This multi-modal pilot study used both positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to evaluate dopaminergic and neural activity, respectively, using modified versions of the monetary incentive delay task. Twelve healthy female subjects underwent both scans and completed the NEO Personality Inventory Revised to assess Impulsiveness (IMP). We examined the relationship between nucleus accumbens (NAcc) dopaminergic incentive/reward release, measured as a change in D2/D3 binding potential between neutral and incentive/reward conditions with [11C]raclopride PET, and blood oxygen level-dependent (BOLD) activation elicited during the anticipation of rewards, measured with fMRI. Left NAcc incentive/reward dopaminergic release correlated with anticipatory reward activation within the medial prefrontal cortex (mPFC), left angular gyrus, mammillary bodies, and left superior frontal cortex. Activation in the mPFC negatively correlated with IMP and mediated the relationship between IMP and incentive/reward dopaminergic release in left NAcc. The mPFC, with a regulatory role in learning and valuation, may influence dopamine incentive/reward release. PMID:24969539

  4. Relation of obesity to neural activation in response to food commercials.

    PubMed

    Gearhardt, Ashley N; Yokum, Sonja; Stice, Eric; Harris, Jennifer L; Brownell, Kelly D

    2014-07-01

    Adolescents view thousands of food commercials annually, but the neural response to food advertising and its association with obesity is largely unknown. This study is the first to examine how neural response to food commercials differs from other stimuli (e.g. non-food commercials and television show) and to explore how this response may differ by weight status. The blood oxygen level-dependent functional magnetic resonance imaging activation was measured in 30 adolescents ranging from lean to obese in response to food and non-food commercials imbedded in a television show. Adolescents exhibited greater activation in regions implicated in visual processing (e.g. occipital gyrus), attention (e.g. parietal lobes), cognition (e.g. temporal gyrus and posterior cerebellar lobe), movement (e.g. anterior cerebellar cortex), somatosensory response (e.g. postcentral gyrus) and reward [e.g. orbitofrontal cortex and anterior cingulate cortex (ACC)] during food commercials. Obese participants exhibited less activation during food relative to non-food commercials in neural regions implicated in visual processing (e.g. cuneus), attention (e.g. posterior cerebellar lobe), reward (e.g. ventromedial prefrontal cortex and ACC) and salience detection (e.g. precuneus). Obese participants did exhibit greater activation in a region implicated in semantic control (e.g. medial temporal gyrus). These findings may inform current policy debates regarding the impact of food advertising to minors. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  5. Relation of obesity to neural activation in response to food commercials

    PubMed Central

    Yokum, Sonja; Stice, Eric; Harris, Jennifer L.; Brownell, Kelly D.

    2014-01-01

    Adolescents view thousands of food commercials annually, but the neural response to food advertising and its association with obesity is largely unknown. This study is the first to examine how neural response to food commercials differs from other stimuli (e.g. non-food commercials and television show) and to explore how this response may differ by weight status. The blood oxygen level-dependent functional magnetic resonance imaging activation was measured in 30 adolescents ranging from lean to obese in response to food and non-food commercials imbedded in a television show. Adolescents exhibited greater activation in regions implicated in visual processing (e.g. occipital gyrus), attention (e.g. parietal lobes), cognition (e.g. temporal gyrus and posterior cerebellar lobe), movement (e.g. anterior cerebellar cortex), somatosensory response (e.g. postcentral gyrus) and reward [e.g. orbitofrontal cortex and anterior cingulate cortex (ACC)] during food commercials. Obese participants exhibited less activation during food relative to non-food commercials in neural regions implicated in visual processing (e.g. cuneus), attention (e.g. posterior cerebellar lobe), reward (e.g. ventromedial prefrontal cortex and ACC) and salience detection (e.g. precuneus). Obese participants did exhibit greater activation in a region implicated in semantic control (e.g. medial temporal gyrus). These findings may inform current policy debates regarding the impact of food advertising to minors. PMID:23576811

  6. Relationship between impulsivity, prefrontal anticipatory activation, and striatal dopamine release during rewarded task performance.

    PubMed

    Weiland, Barbara J; Heitzeg, Mary M; Zald, David; Cummiford, Chelsea; Love, Tiffany; Zucker, Robert A; Zubieta, Jon-Kar

    2014-09-30

    Impulsivity, and in particular the negative urgency aspect of this trait, is associated with poor inhibitory control when experiencing negative emotion. Individual differences in aspects of impulsivity have been correlated with striatal dopamine D2/D3 receptor availability and function. This multi-modal pilot study used both positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to evaluate dopaminergic and neural activity, respectively, using modified versions of the monetary incentive delay task. Twelve healthy female subjects underwent both scans and completed the NEO Personality Inventory Revised to assess Impulsiveness (IMP). We examined the relationship between nucleus accumbens (NAcc) dopaminergic incentive/reward release, measured as a change in D2/D3 binding potential between neutral and incentive/reward conditions with [(11)C]raclopride PET, and blood oxygen level-dependent (BOLD) activation elicited during the anticipation of rewards, measured with fMRI. Left NAcc incentive/reward dopaminergic release correlated with anticipatory reward activation within the medial prefrontal cortex (mPFC), left angular gyrus, mammillary bodies, and left superior frontal cortex. Activation in the mPFC negatively correlated with IMP and mediated the relationship between IMP and incentive/reward dopaminergic release in left NAcc. The mPFC, with a regulatory role in learning and valuation, may influence dopamine incentive/reward release. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  7. Cortical activation during visual illusory walking in persons with spinal cord injury: A pilot study

    PubMed Central

    Eick, John; Richardson, Elizabeth J.

    2014-01-01

    Objective To determine the location of cortical activation during a visual illusion walking paradigm, a recently proposed treatment for spinal cord injury (SCI)-related neuropathic pain, in persons with SCI compared to able-bodied controls. Design Pilot experimental fMRI trial. Setting Outpatient rehabilitation clinic. Participants Three persons with paraplegia and five able bodied participants were included in this study. Interventions Not applicable. Main Outcome Measures Cortical activation as measured by blood oxygenation-level dependent (BOLD) method of fMRI. Results During visually illusory walking, there was significant activation in the somatosensory cortex among those with SCI. In contrast, able-bodied participants showed little to no significant activation in this area, but rather, in the frontal and pre-motor areas. Conclusions Treatment modalities for SCI-related neuropathic pain that are based on sensory input paradigms such as virtual or visual illusory walking may work by targeting somatosensory cortex, an area that has been previously found to functionally reorganize following SCI. PMID:25461820

  8. Physical Activity Assessment

    Cancer.gov

    Current evidence convincingly indicates that physical activity reduces the risk of colon and breast cancer. Physical activity may also reduce risk of prostate cancer. Scientists are also evaluating potential relationships between physical activity and other cancers.

  9. Measuring Physical Activity Intensity

    MedlinePlus

    ... Life Activities for Children Activities for Older Adults Overcoming Barriers Measuring Physical Activity Intensity Target Heart Rate & ... DFCN Promotion Implementation Maintaining Interest Needs Assessment Evaluating Success CDC’s Example StairWELL Stairwell Appearance Motivational Signs Installing ...

  10. Physical Activity Guidelines

    MedlinePlus

    ... gov Physical Activity Guidelines Physical Activity Guidelines The Physical Activity Guidelines for Americans (PAG or the Guidelines) are an essential resource for health professional and policymakers. Based on the latest science, they provide guidance on how children and adults ...

  11. Forming Polymers. Learning Activity.

    ERIC Educational Resources Information Center

    Shackelford, Ray

    1997-01-01

    Offers a technology education activity on the subject of manufacturing processes. Includes background information, concepts presented, objectives, equipment list, procedures, and suggested follow-up activities. (JOW)

  12. Effect of Bupropion Treatment on Brain Activation Induced by Cigarette-Related Cues in Smokers

    PubMed Central

    Culbertson, Christopher S.; Bramen, Jennifer; Cohen, Mark S.; London, Edythe D.; Olmstead, Richard E.; Gan, Joanna J.; Costello, Matthew R.; Shulenberger, Stephanie; Mandelkern, Mark A.; Brody, Arthur L.

    2011-01-01

    Context Nicotine-dependent smokers exhibit craving and brain activation in the prefrontal and limbic regions when presented with cigarette-related cues. Bupropion hydrochloride treatment reduces cue-induced craving in cigarette smokers; however, the mechanism by which bupropion exerts this effect has not yet been described. Objective To assess changes in regional brain activation in response to cigarette-related cues from before to after treatment with bupropion (vs placebo). Design Randomized, double-blind, before-after controlled trial. Setting Academic brain imaging center. Participants Thirty nicotine-dependent smokers (paid volunteers). Interventions Participants were randomly assigned to receive 8 weeks of treatment with either bupropion or a matching placebo pill (double-blind). Main Outcome Measures Subjective cigarette craving ratings and regional brain activations (blood oxygen level-dependent response) in response to viewing cue videos. Results Bupropion-treated participants reported less craving and exhibited reduced activation in the left ventral striatum, right medial orbitofrontal cortex, and bilateral anterior cingulate cortex from before to after treatment when actively resisting craving compared with placebo-treated participants. When resisting craving, reduction in self-reported craving correlated with reduced regional brain activation in the bilateral medial orbitofrontal and left anterior cingulate cortices in all participants. Conclusions Treatment with bupropion is associated with improved ability to resist cue-induced craving and a reduction in cue-induced activation of limbic and prefrontal brain regions, while a reduction in craving, regardless of treatment type, is associated with reduced activation in prefrontal brain regions. PMID:21199957

  13. Deficient activity in the neural systems that mediate self-regulatory control in bulimia nervosa.

    PubMed

    Marsh, Rachel; Steinglass, Joanna E; Gerber, Andrew J; Graziano O'Leary, Kara; Wang, Zhishun; Murphy, David; Walsh, B Timothy; Peterson, Bradley S

    2009-01-01

    Disturbances in neural systems that mediate voluntary self-regulatory processes may contribute to bulimia nervosa (BN) by releasing feeding behaviors from regulatory control. To study the functional activity in neural circuits that subserve self-regulatory control in women with BN. We compared functional magnetic resonance imaging blood oxygenation level-dependent responses in patients with BN with healthy controls during performance of the Simon Spatial Incompatibility task. University research institute. Forty women: 20 patients with BN and 20 healthy control participants. Main Outcome Measure We used general linear modeling of Simon Spatial Incompatibility task-related activations to compare groups on their patterns of brain activation associated with the successful or unsuccessful engagement of self-regulatory control. Patients with BN responded more impulsively and made more errors on the task than did healthy controls; patients with the most severe symptoms made the most errors. During correct responding on incongruent trials, patients failed to activate frontostriatal circuits to the same degree as healthy controls in the left inferolateral prefrontal cortex (Brodmann area [BA] 45), bilateral inferior frontal gyrus (BA 44), lenticular and caudate nuclei, and anterior cingulate cortex (BA 24/32). Patients activated the dorsal anterior cingulate cortex (BA 32) more when making errors than when responding correctly. In contrast, healthy participants activated the anterior cingulate cortex more during correct than incorrect responses, and they activated the striatum more when responding incorrectly, likely reflecting an automatic response tendency that, in the absence of concomitant anterior cingulate cortex activity, produced incorrect responses. Self-regulatory processes are impaired in women with BN, likely because of their failure to engage frontostriatal circuits appropriately. These findings enhance our understanding of the pathogenesis of BN by pointing

  14. Political activity for physical activity: health advocacy for active transport

    PubMed Central

    2011-01-01

    Effective health advocacy is a priority for efforts to increase population participation in physical activity. Local councils are an important audience for this advocacy. The aim of the current study was to describe features of advocacy for active transport via submissions to city council annual plans in New Zealand, and the impact of an information sheet to encourage the health sector to be involved in this process. Written submissions to city council's annual consultation process were requested for 16 city councils over the period of three years (2007/08, 2008/09, and 2009/10). Submissions were reviewed and categories of responses were created. An advocacy information sheet encouraging health sector participation and summarising some of the evidence-base related to physical activity, active transport and health was released just prior to the 2009/10 submission time. Over the period of the study, city councils received 47,392 submissions, 17% of which were related to active transport. Most submissions came from city residents, with a small proportion (2%) from the health sector. The largest category of submissions was in support of pedestrian and cycling infrastructure, design and maintenance of facilities and additional features to support use of these transport modes. Health arguments featured prominently in justifications for active transport initiatives, including concerns about injury risk, obesity, physical inactivity, personal safety and facilities for people with disabilities. There was evidence that the information sheet was utilised by some health sector submitters (12.5%), providing tentative support for initiatives of this nature. In conclusion, the study provides novel information about the current nature of health advocacy for active transport and informs future advocacy efforts about areas for emphasis, such as health benefits of active transport, and potential alliances with other sectors such as environmental sustainability, transport and urban

  15. Blockade of the brachial plexus abolishes activation of specific brain regions by electroacupuncture at LI4: a functional MRI study

    PubMed Central

    Gu, Weidong; Jiang, Wei; He, Jingwei; Liu, Songbin; Wang, Zhaoxin

    2015-01-01

    Objective Our aim was to test the hypothesis that electroacupuncture (EA) at acupuncture point LI4 activates specific brain regions by nerve stimulation that is mediatied through a pathway involving the brachial plexus. Methods Twelve acupuncture naive right-handed volunteers were allocated to receive three sessions of EA at LI4 in a random different order (crossover): (1) EA alone (EA); EA after injection of local anaesthetics into the deltoid muscle (EA+LA); and (3) EA after blockade of the brachial plexus (EA+NB). During each session, participants were imaged in a 3 T MRI scanner. Brain regions showing change in blood oxygen level-dependent (BOLD) signal (activation) were identified. Subjective acupuncture sensation was quantified after functional MRI scanning was completed. Results were compared between the three sessions for each individual, and averaged. Results Blockade of the brachial plexus inhibited acupuncture sensation during EA. EA and EA+LA activated the bilateral thalamus, basal ganglia, cerebellum and left putamen, whilst no significant activation was observed during EA+NB. The BOLD signal of the thalamus correlated significantly with acupuncture sensation score during EA. Conclusions Blockade of the brachial plexus completely abolishes patterns of brain activation induced by EA at LI4. The results suggest that EA activates specific brain regions through stimulation of the local nerves supplying the tissues at LI4, which transmit sensory information via the brachial plexus. Trial registration number ChiCTR-OO-13003389. PMID:26464415

  16. Active commuting to school

    USDA-ARS?s Scientific Manuscript database

    Declines in physical activity levels have coincided with increasing rates of obesity in children. This is problematic because physical activity has been shown to attenuate weight gain in children. Active commuting to school is one way of increasing children's physical activity. However, given the hi...

  17. Home Activities for Fours.

    ERIC Educational Resources Information Center

    Ferguson-Florissant School District, Ferguson, MO.

    These home learning activity guides have been developed for parents to use with their 4-year-old children. Most of the activities require only household items that are often thrown away and can be recycled for learning activities. Some require no materials at all. The guides frequently begin with a discussion of home activities; progress through…

  18. Civil Law: 12 Activities.

    ERIC Educational Resources Information Center

    Dresbach, Debra

    These learning activities on civil law are intended to supplement the secondary level Scholastic materials "Living Law." Case studies, simulations, and role-play activities are included. Information provided for each activity includes a brief overview, background information, teacher instructions and a description of each activity.…

  19. Increasing Youth Physical Activity with Activity Calendars

    ERIC Educational Resources Information Center

    Eckler, Seth

    2016-01-01

    Physical educators often struggle with ways to get their students to be active beyond the school day. One strategy to accomplish this is the use of physical activity calendars (PACs). The purpose of this article is to support the use of PACs and give practical advice for creating effective PACs.

  20. Increasing Youth Physical Activity with Activity Calendars

    ERIC Educational Resources Information Center

    Eckler, Seth

    2016-01-01

    Physical educators often struggle with ways to get their students to be active beyond the school day. One strategy to accomplish this is the use of physical activity calendars (PACs). The purpose of this article is to support the use of PACs and give practical advice for creating effective PACs.

  1. UV activation of receptor tyrosine kinase activity.

    PubMed

    Coffer, P J; Burgering, B M; Peppelenbosch, M P; Bos, J L; Kruijer, W

    1995-08-03

    The exposure of mammalian cells to ultraviolet radiation (UV) may lead to DNA damage resulting in mutation and thus possibly cancer, while irradiation can further act as a potent tumor promoter. In addition UV induces p21ras-mediated signalling leading to activation of transcription factors such as AP-1 and NF-kappa B, as well as activation of the Src tyrosine kinase. This 'UV-response' has been well studied in mammalian cells and furthermore is conserved in yeast, however the most upstream components of this signal transduction pathway have remained elusive. Here we show that UV rapidly activates both the EGF receptor and insulin receptor, as shown by tyrosine phosphorylation of these receptors. We demonstrate that this activation is due to autophosphorylation as it only occurs in cells containing receptors with a functional kinase domain. We have further analysed the propagation of the UV-induced signal to downstream events such as, IRS-1 and Shc tyrosine phosphorylation, phosphatidylinositol 3-kinase activation, leukotriene synthesis, MAP kinase activation and gene induction all of which are activated by UV irradiation. Importantly, we demonstrate that in cells expressing a 'kinase-dead' receptor mutant the UV-response is inhibited, blocking leukotriene synthesis, MAP kinase activation and transcriptional induction. Furthermore, prior-stimulation of cells with UV appears to reduce further responsiveness to addition of growth factor suggesting a common signaling pathway. These data demonstrate a critical role for receptor-mediated events in regulating the response mammalian cells to UV exposure.

  2. Effects of cranial electrotherapy stimulation on resting state brain activity

    PubMed Central

    Feusner, Jamie D; Madsen, Sarah; Moody, Teena D; Bohon, Cara; Hembacher, Emily; Bookheimer, Susan Y; Bystritsky, Alexander

    2012-01-01

    Cranial electrotherapy stimulation (CES) is a U.S. Food and Drug Administration (FDA)-approved treatment for insomnia, depression, and anxiety consisting of pulsed, low-intensity current applied to the earlobes or scalp. Despite empirical evidence of clinical efficacy, its mechanism of action is largely unknown. The goal was to characterize the acute effects of CES on resting state brain activity. Our primary hypothesis was that CES would result in deactivation in cortical and subcortical regions. Eleven healthy controls were administered CES applied to the earlobes at subsensory thresholds while being scanned with functional magnetic resonance imaging in the resting state. We tested 0.5- and 100-Hz stimulation, using blocks of 22 sec “on” alternating with 22 sec of baseline (device was “off”). The primary outcome measure was differences in blood oxygen level dependent data associated with the device being on versus baseline. The secondary outcome measures were the effects of stimulation on connectivity within the default mode, sensorimotor, and fronto-parietal networks. Both 0.5- and 100-Hz stimulation resulted in significant deactivation in midline frontal and parietal regions. 100-Hz stimulation was associated with both increases and decreases in connectivity within the default mode network (DMN). Results suggest that CES causes cortical brain deactivation, with a similar pattern for high- and low-frequency stimulation, and alters connectivity in the DMN. These effects may result from interference from high- or low-frequency noise. Small perturbations of brain oscillations may therefore have significant effects on normal resting state brain activity. These results provide insight into the mechanism of action of CES, and may assist in the future development of optimal parameters for effective treatment. PMID:22741094

  3. Cerebral Oxygen Delivery and Consumption During Evoked Neural Activity

    PubMed Central

    Vazquez, Alberto L.; Masamoto, Kazuto; Fukuda, Mitsuhiro; Kim, Seong-Gi

    2010-01-01

    Increases in neural activity evoke increases in the delivery and consumption of oxygen. Beyond observations of cerebral tissue and blood oxygen, the role and properties of cerebral oxygen delivery and consumption during changes in brain function are not well understood. This work overviews the current knowledge of functional oxygen delivery and consumption and introduces recent and preliminary findings to explore the mechanisms by which oxygen is delivered to tissue as well as the temporal dynamics of oxygen metabolism. Vascular oxygen tension measurements have shown that a relatively large amount of oxygen exits pial arterioles prior to capillaries. Additionally, increases in cerebral blood flow (CBF) induced by evoked neural activation are accompanied by arterial vasodilation and also by increases in arteriolar oxygenation. This increase contributes not only to the down-stream delivery of oxygen to tissue, but also to delivery of additional oxygen to extra-vascular spaces surrounding the arterioles. On the other hand, the changes in tissue oxygen tension due to functional increases in oxygen consumption have been investigated using a method to suppress the evoked CBF response. The functional decreases in tissue oxygen tension induced by increases in oxygen consumption are slow to evoked changes in CBF under control conditions. Preliminary findings obtained using flavoprotein autofluorescence imaging suggest cellular oxidative metabolism changes at a faster rate than the average changes in tissue oxygen. These issues are important in the determination of the dynamic changes in tissue oxygen metabolism from hemoglobin-based imaging techniques such as blood oxygenation-level dependent functional magnetic resonance imaging (fMRI). PMID:20616881

  4. The relationship between oscillatory EEG activity and the laminar-specific BOLD signal

    PubMed Central

    Scheeringa, René; Koopmans, Peter J.; van Mourik, Tim; Jensen, Ole; Norris, David G.

    2016-01-01

    Electrophysiological recordings in animals have indicated that visual cortex γ-band oscillatory activity is predominantly observed in superficial cortical layers, whereas α- and β-band activity is stronger in deep layers. These rhythms, as well as the different cortical layers, have also been closely related to feedforward and feedback streams of information. Recently, it has become possible to measure laminar activity in humans with high-resolution functional MRI (fMRI). In this study, we investigated whether these different frequency bands show a differential relation with the laminar-resolved blood-oxygen level-dependent (BOLD) signal by combining data from simultaneously recorded EEG and fMRI from the early visual cortex. Our visual attention paradigm allowed us to investigate how variations in strength over trials and variations in the attention effect over subjects relate to each other in both modalities. We demonstrate that γ-band EEG power correlates positively with the superficial layers’ BOLD signal and that β-power is negatively correlated to deep layer BOLD and α-power to both deep and superficial layer BOLD. These results provide a neurophysiological basis for human laminar fMRI and link human EEG and high-resolution fMRI to systems-level neuroscience in animals. PMID:27247416

  5. EEG and FMRI coregistration to investigate the cortical oscillatory activities during finger movement.

    PubMed

    Formaggio, Emanuela; Storti, Silvia Francesca; Avesani, Mirko; Cerini, Roberto; Milanese, Franco; Gasparini, Anna; Acler, Michele; Pozzi Mucelli, Roberto; Fiaschi, Antonio; Manganotti, Paolo

    2008-12-01

    Electroencephalography combined with functional magnetic resonance imaging (EEG-fMRI) may be used to identify blood oxygenation level dependent (BOLD) signal changes associated with physiological and pathological EEG event. In this study we used EEG-fMRI to determine the possible correlation between topographical movement-related EEG changes in brain oscillatory activity recorded from EEG electrodes over the scalp and fMRI-BOLD cortical responses in motor areas during finger movement. Thirty-two channels of EEG were recorded in 9 subjects during eyes-open condition inside a 1.5 T magnetic resonance (MR) scanner using a MR-compatible EEG recording system. Off-line MRI artifact subtraction software was applied to obtain continuous EEG data during fMRI acquisition. For EEG data analysis we used the event-related-synchronization/desynchronization (ERS/ERD) approach to investigate where movement-related decreases in alpha and beta power are located. For image statistical analysis we used a general linear model (GLM) approach. There was a significant correlation between the positive-negative ratio of BOLD signal peaks and ERD values in the electrodes over the region of activation. We conclude that combined EEG-fMRI may be used to investigate movement-related oscillations of the human brain inside an MRI scanner and the movement-related changes in the EMG or EEG signals are useful to identify the brain activation sources responsible for BOLD-signal changes.

  6. Personality predicts activity in reward and emotional regions associated with humor.

    PubMed

    Mobbs, Dean; Hagan, Cindy C; Azim, Eiman; Menon, Vinod; Reiss, Allan L

    2005-11-08

    Previous research and theory suggest that two stable personality dimensions, extroversion and neuroticism, differentially influence emotional reactivity to a variety of pleasurable phenomena. Here, we use event-related functional MRI to address the putative neural and behavioral associations between humor appreciation and the personality dimensions of introversion-extroversion and emotional stability-neuroticism. Our analysis showed extroversion to positively correlate with humor-driven blood oxygenation level-dependent signal in discrete regions of the right orbital frontal cortex, ventrolateral prefrontal cortex, and bilateral temporal cortices. Introversion correlated with increased activation in several regions, most prominently the bilateral amygdala. Although neuroticism did not positively correlate with any whole-brain activation, emotional stability (i.e., the inverse of neuroticism) correlated with increased activation in the mesocortical-mesolimbic reward circuitry encompassing the right orbital frontal cortex, caudate, and nucleus accumbens. Our findings tie together existing neurobiological studies of humor appreciation and are compatible with the notion that personality style plays a fundamental role in the neurobiological systems subserving humor appreciation.

  7. Atypical parietal lobe activity to subliminal faces in youth with a family history of alcoholism

    PubMed Central

    Peraza, Jennifer; Cservenka, Anita; Herting, Megan M.; Nagel, Bonnie J.

    2015-01-01

    Background Adults with alcohol use disorders (AUDs) show different behavioral and neurological functioning during emotional processing tasks from healthy controls. Adults with a family history (FHP) of AUD also show different activation in limbic brain areas, such as the amygdala. However, it is unclear if this pattern exists during adolescence before any episodes of heavy alcohol use. Objectives We hypothesized that the amygdalar response to subliminally-presented fearful faces would be reduced in FHP adolescents compared to peers who were family history negative (FHN) for AUD. Method An adapted Masked Faces paradigm was used to examine blood oxygen level-dependent response to subliminal fearful vs. neutral faces in 14 FHP (6 females, 8 males) and 15 FHN (6 females, 9 males) youth, ages 11–15 years. Both FHP and FHN youth had no history of heavy alcohol consumption. Results A significant difference was seen between groups in the left superior parietal lobule FHN youth showed deactivation to fearful and neutral masked faces compared to baseline, whereas FHP youth showed deactivation only to fearful masked faces. No significant differences in amygdalar activation were seen between groups. Conclusion The left superior parietal lobule is part of the fronto-parietal network, which has been implicated in attentional control. Lack of reduced neural activity to neutral faces among FHP youth may represent differences in suppressing attention networks to less salient emotional stimuli, or perhaps, a higher threshold of saliency for emotional stimuli among at-risk youth. PMID:25268683

  8. Decoding the Semantic Content of Natural Movies from Human Brain Activity

    PubMed Central

    Huth, Alexander G.; Lee, Tyler; Nishimoto, Shinji; Bilenko, Natalia Y.; Vu, An T.; Gallant, Jack L.

    2016-01-01

    One crucial test for any quantitative model of the brain is to show that the model can be used to accurately decode information from evoked brain activity. Several recent neuroimaging studies have decoded the structure or semantic content of static visual images from human brain activity. Here we present a decoding algorithm that makes it possible to decode detailed information about the object and action categories present in natural movies from human brain activity signals measured by functional MRI. Decoding is accomplished using a hierarchical logistic regression (HLR) model that is based on labels that were manually assigned from the WordNet semantic taxonomy. This model makes it possible to simultaneously decode information about both specific and general categories, while respecting the relationships between them. Our results show that we can decode the presence of many object and action categories from averaged blood-oxygen level-dependent (BOLD) responses with a high degree of accuracy (area under the ROC curve > 0.9). Furthermore, we used this framework to test whether semantic relationships defined in the WordNet taxonomy are represented the same way in the human brain. This analysis showed that hierarchical relationships between general categories and atypical examples, such as organism and plant, did not seem to be reflected in representations measured by BOLD fMRI. PMID:27781035

  9. Propagated infra-slow intrinsic brain activity reorganizes across wake and slow wave sleep

    PubMed Central

    Mitra, Anish; Snyder, Abraham Z; Tagliazucchi, Enzo; Laufs, Helmut; Raichle, Marcus E

    2015-01-01

    Propagation of slow intrinsic brain activity has been widely observed in electrophysiogical studies of slow wave sleep (SWS). However, in human resting state fMRI (rs-fMRI), intrinsic activity has been understood predominantly in terms of zero-lag temporal synchrony (functional connectivity) within systems known as resting state networks (RSNs). Prior rs-fMRI studies have found that RSNs are generally preserved across wake and sleep. Here, we use a recently developed analysis technique to study propagation of infra-slow intrinsic blood oxygen level dependent (BOLD) signals in normal adults during wake and SWS. This analysis reveals marked changes in propagation patterns in SWS vs. wake. Broadly, ordered propagation is preserved within traditionally defined RSNs but lost between RSNs. Additionally, propagation between cerebral cortex and subcortical structures reverses directions, and intra-cortical propagation becomes reorganized, especially in visual and sensorimotor cortices. These findings show that propagated rs-fMRI activity informs theoretical accounts of the neural functions of sleep. DOI: http://dx.doi.org/10.7554/eLife.10781.001 PMID:26551562

  10. Changes in the regional homogeneity of resting-state brain activity in minimal hepatic encephalopathy.

    PubMed

    Chen, Hua-Jun; Zhu, Xi-Qi; Yang, Ming; Liu, Bin; Zhang, Yi; Wang, Yu; Teng, Gao-Jun

    2012-01-17

    Resting-state functional magnetic resonance imaging (fMRI) has facilitated the study of spontaneous brain activity by measuring low-frequency oscillations in blood-oxygen-level-dependent signals. Analyses of regional homogeneity (ReHo), which reflects the local synchrony of neural activity, have been used to reveal the mechanisms underlying the brain dysfunction in various neuropsychiatric diseases. However, it is not known whether the ReHo is altered in cirrhotic patients with minimal hepatic encephalopathy (MHE). We recruited 18 healthy controls and 18 patients with MHE. The ReHo was calculated to assess the strength of the local signal synchrony. Compared with the healthy controls, the patients with MHE had significantly decreased ReHo in the cuneus and adjacent precuneus, and left inferior parietal lobe, whereas the regions showing increased ReHo in patients with MHE included the left parahippocampal gyrus, right cerebellar vermis, and bilateral anterior cerebellar lobes. We found a positive correlation between the mean ReHo in the cuneus and adjacent precuneus and the score on the digit-symbol test in the patient group. In conclusion, the analysis of the regional homogeneity of resting-state brain activity may provide additional information with respect to a clinical definition of MHE.

  11. [Multineuronal characteristics of brain activation during extinction of the effects of indifferent stimuli].

    PubMed

    Kratin, Iu G; Panteleev, S S

    1980-01-01

    In chronic experiments on cats, the correlation of multineuronal activity (MNA) in the somatosensory cortex with EEG activation reactions recorded at the same point was studied during the process of extinction. The MNA was discriminated in three amplitude levels and averaged by means of a computer. Three kinds of stimuli were used: electric shocks to the forepaw, sounds and direct stimulation of the midbrain reticular formation. It was found that with repetition of stimuli, the progressive inhibition of the EEG activation correlates with gradual reduction of the level of sharp increase of MNA frequency in response to stimulation, and with shortening of the poststimuli periods of prolonged frequency reduction. A minor part of neuronal populations reacted with a slowing down of the discharge frequency (e. g. to the sound and reticular stimulation). More specific frequency reactions during extinction were recorded at different amplitude levels, depending on the modality and the parameters of the stimuli and on the population type. The changes in multineuronal discharges rate were more diverse and more continuous than the EEG responses. A comparative study of both phenomena reveals only partial coherence between them.

  12. Spatio-temporal activity in real time (STAR): Optimization of regional fMRI feedback

    PubMed Central

    Magland, Jeremy F.; Tjoa, Christopher W.; Childress, Anna Rose

    2011-01-01

    The use of real-time feedback has expanded fMRI from a brain probe to include potential brain interventions with significant therapeutic promise. However, whereas time-averaged blood oxygenation level-dependent (BOLD) signal measurement is usually sufficient for probing a brain state, the real-time (frame-to-frame) BOLD signal is noisy, compromising feedback accuracy. We have developed a new real-time processing technique (STAR) that combines noise-reduction properties of multi-voxel (e.g., whole-brain) techniques with the regional specificity critical for therapeutics. Nineteen subjects were given real-time feedback in a cognitive control task (imagining repetitive motor activity vs. spatial navigation), and were all able to control a visual feedback cursor based on whole-brain neural activity. The STAR technique was evaluated, retrospectively, for five a priori regions of interest in these data, and was shown to provide significantly better (frame-by-frame) classification accuracy than a regional BOLD technique. In addition to regional feedback signals, the output of the STAR technique includes spatio-temporal activity maps (movies) providing insight into brain dynamics. The STAR approach offers an appealing optimization for real-time fMRI applications requiring an anatomically-localized feedback signal. PMID:21232612

  13. Input permutation method to detect active voxels in fMRI study☆

    PubMed Central

    Lee, Sang H.; Lim, Johan; Park, DoHwan; Biswal, Bharat B.; Petkova, Eva

    2013-01-01

    Correctly identifying voxels or regions of interest (ROI) that actively respond to a given stimulus is often an important objective/step in many functional magnetic resonance imaging (fMRI) studies. In this article, we study a nonparametric method to detect active voxels, which makes minimal assumption about the distribution of blood oxygen level-dependent (BOLD) signals. Our proposal has several interesting features. It uses time lagged correlation to take into account the delay in response to the stimulus, due to hemodynamic variations. We introduce an input permutation method (IPM), a type of block permutation method, to approximate the null distribution of the test statistic. Also, we propose to pool the permutation-derived statistics of preselected voxels for a better approximation to the null distribution. Finally, we control multiple testing error rate using the local false discovery rate (FDR) by Efron [Correlation and large-scale simultaneous hypothesis testing. J Am Stat Assoc 102 (2007) 93–103] and Park et al. [Estimation of empirical null using a mixture of normals and its use in local false discovery rate. Comput Stat Data Anal 55 (2011) 2421–2432] to select the active voxels. PMID:22819177

  14. Increased anterior cingulate cortex and hippocampus activation in Complex PTSD during encoding of negative words

    PubMed Central

    Dorrepaal, Ethy; Draijer, Nel; de Ruiter, Michiel B.; Elzinga, Bernet M.; Sjoerds, Zsuzsika; van Balkom, Anton J.; Smit, Johannes H.; Veltman, Dick J.

    2013-01-01

    Post-traumatic stress disorder (PTSD) is associated with impaired memory performance coupled with functional changes in brain areas involved in declarative memory and emotion regulation. It is not yet clear how symptom severity and comorbidity affect neurocognitive functioning in PTSD. We performed a functional magnetic resonance imaging (fMRI) study with an emotional declarative memory task in 28 Complex PTSD patients with comorbid depressive and personality disorders, and 21 healthy non-trauma-exposed controls. In Complex PTSD patients—compared to controls—encoding of later remembered negative words vs baseline was associated with increased blood oxygenation level dependent (BOLD) response in the left ventral anterior cingulate cortex (ACC) and dorsal ACC extending to the dorsomedial prefrontal cortex (dmPFC) together with a trend for increased left hippocampus activation. Patients tended to commit more False Alarms to negative words compared to controls, which was associated with enhanced left ventrolateral prefrontal and orbitofrontal cortex (vlPFC/OFC) responses. Severity of child abuse was positively correlated with left ventral ACC activity and severity of depression with (para) hippocampal and ventral ACC activity. Presented results demonstrate functional abnormalities in Complex PTSD in the frontolimbic brain circuit also implicated in fear conditioning models, but generally in the opposite direction, which may be explained by severity of the trauma and severity of comorbid depression in Complex PTSD. PMID:22156722

  15. Spatio-temporal activity in real time (STAR): optimization of regional fMRI feedback.

    PubMed

    Magland, Jeremy F; Tjoa, Christopher W; Childress, Anna Rose

    2011-04-01

    The use of real-time feedback has expanded fMRI from a brain probe to include potential brain interventions with significant therapeutic promise. However, whereas time-averaged blood oxygenation level-dependent (BOLD) signal measurement is usually sufficient for probing a brain state, the real-time (frame-to-frame) BOLD signal is noisy, compromising feedback accuracy. We have developed a new real-time processing technique (STAR) that combines noise-reduction properties of multi-voxel (e.g., whole-brain) techniques with the regional specificity critical for therapeutics. Nineteen subjects were given real-time feedback in a cognitive control task (imagining repetitive motor activity vs. spatial navigation), and were all able to control a visual feedback cursor based on whole-brain neural activity. The STAR technique was evaluated, retrospectively, for five a priori regions of interest in these data, and was shown to provide significantly better (frame-by-frame) classification accuracy than a regional BOLD technique. In addition to regional feedback signals, the output of the STAR technique includes spatio-temporal activity maps (movies) providing insight into brain dynamics. The STAR approach offers an appealing optimization for real-time fMRI applications requiring an anatomically-localized feedback signal. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Auditory selective attention to speech modulates activity in the visual word form area.

    PubMed

    Yoncheva, Yuliya N; Zevin, Jason D; Maurer, Urs; McCandliss, Bruce D

    2010-03-01

    Selective attention to speech versus nonspeech signals in complex auditory input could produce top-down modulation of cortical regions previously linked to perception of spoken, and even visual, words. To isolate such top-down attentional effects, we contrasted 2 equally challenging active listening tasks, performed on the same complex auditory stimuli (words overlaid with a series of 3 tones). Instructions required selectively attending to either the speech signals (in service of rhyme judgment) or the melodic signals (tone-triplet matching). Selective attention to speech, relative to attention to melody, was associated with blood oxygenation level-dependent (BOLD) increases during functional magnetic resonance imaging (fMRI) in left inferior frontal gyrus, temporal regions, and the visual word form area (VWFA). Further investigation of the activity in visual regions revealed overall deactivation relative to baseline rest for both attention conditions. Topographic analysis demonstrated that while attending to melody drove deactivation equivalently across all fusiform regions of interest examined, attending to speech produced a regionally specific modulation: deactivation of all fusiform regions, except the VWFA. Results indicate that selective attention to speech can topographically tune extrastriate cortex, leading to increased activity in VWFA relative to surrounding regions, in line with the well-established connectivity between areas related to spoken and visual word perception in skilled readers.

  17. Renewal of conditioned fear in a novel context is associated with hippocampal activation and connectivity

    PubMed Central

    Stark, R.; Milad, M. R.; Merz, C. J.

    2016-01-01

    Return of fear is a serious problem in exposure-based treatments of anxiety disorders. Renewal of the fear response may occur when re-encountering the conditioned stimulus within a novel context. Findings in rodents underpin the hippocampus’ role in conditioned fear renewal in novel contexts, but it has yet to be investigated in humans. Forty-six healthy men took part in a 2-day, context-dependent, cued fear conditioning paradigm with fear acquisition, extinction learning (day 1) and extinction recall in the acquisition, extinction and a novel context one day later. Conditioned evaluative, skin conductance responses (SCRs) and blood-oxygen-level-dependent responses served as dependent variables. Context-dependent fear renewal was reflected in stronger conditioned SCRs. In the acquisition context, individuals with a higher renewal of conditioned SCRs showed stronger activation of the fear circuit. Hippocampal activation distinguished conditioned responding in the novel compared with the extinction context. Individuals with a stronger renewal of conditioned SCRs in the novel context showed increased effective connectivity of hippocampal activation foci with structures in the fear and extinction network. These results outline the pivotal role of the hippocampus and its connectivity in conditioned fear renewal in a novel context in humans and might have important implications for exposure therapy in anxiety disorders. PMID:27053767

  18. Increased anterior cingulate cortex and hippocampus activation in Complex PTSD during encoding of negative words.

    PubMed

    Thomaes, Kathleen; Dorrepaal, Ethy; Draijer, Nel; de Ruiter, Michiel B; Elzinga, Bernet M; Sjoerds, Zsuzsika; van Balkom, Anton J; Smit, Johannes H; Veltman, Dick J

    2013-02-01

    Post-traumatic stress disorder (PTSD) is associated with impaired memory performance coupled with functional changes in brain areas involved in declarative memory and emotion regulation. It is not yet clear how symptom severity and comorbidity affect neurocognitive functioning in PTSD. We performed a functional magnetic resonance imaging (fMRI) study with an emotional declarative memory task in 28 Complex PTSD patients with comorbid depressive and personality disorders, and 21 healthy non-trauma-exposed controls. In Complex PTSD patients--compared to controls--encoding of later remembered negative words vs baseline was associated with increased blood oxygenation level dependent (BOLD) response in the left ventral anterior cingulate cortex (ACC) and dorsal ACC extending to the dorsomedial prefrontal cortex (dmPFC) together with a trend for increased left hippocampus activation. Patients tended to commit more False Alarms to negative words compared to controls, which was associated with enhanced left ventrolateral prefrontal and orbitofrontal cortex (vlPFC/OFC) responses. Severity of child abuse was positively correlated with left ventral ACC activity and severity of depression with (para) hippocampal and ventral ACC activity. Presented results demonstrate functional abnormalities in Complex PTSD in the frontolimbic brain circuit also implicated in fear conditioning models, but generally in the opposite direction, which may be explained by severity of the trauma and severity of comorbid depression in Complex PTSD.

  19. Atypical parietal lobe activity to subliminal faces in youth with a family history of alcoholism.

    PubMed

    Peraza, Jennifer; Cservenka, Anita; Herting, Megan M; Nagel, Bonnie J

    2015-03-01

    Adults with alcohol use disorders (AUDs) show different behavioral and neurological functioning during emotional processing tasks from healthy controls. Adults with a family history (FHP) of AUD also show different activation in limbic brain areas, such as the amygdala. However, it is unclear if this pattern exists during adolescence before any episodes of heavy alcohol use. We hypothesized that the amygdalar response to subliminally-presented fearful faces would be reduced in FHP adolescents compared to peers who were family history negative (FHN) for AUD. An adapted Masked Faces paradigm was used to examine blood oxygen level-dependent response to subliminal fearful vs. neutral faces in 14 FHP (6 females, 8 males) and 15 FHN (6 females, 9 males) youth, ages 11-15 years. Both FHP and FHN youth had no history of heavy alcohol consumption. A significant difference was seen between groups in the left superior parietal lobule FHN youth showed deactivation to fearful and neutral masked faces compared to baseline, whereas FHP youth showed deactivation only to fearful masked faces. No significant differences in amygdalar activation were seen between groups. The left superior parietal lobule is part of the fronto-parietal network, which has been implicated in attentional control. Lack of reduced neural activity to neutral faces among FHP youth may represent differences in suppressing attention networks to less salient emotional stimuli, or perhaps, a higher threshold of saliency for emotional stimuli among at-risk youth.

  20. Propagated infra-slow intrinsic brain activity reorganizes across wake and slow wave sleep.

    PubMed

    Mitra, Anish; Snyder, Abraham Z; Tagliazucchi, Enzo; Laufs, Helmut; Raichle, Marcus E

    2015-11-09

    Propagation of slow intrinsic brain activity has been widely observed in electrophysiogical studies of slow wave sleep (SWS). However, in human resting state fMRI (rs-fMRI), intrinsic activity has been understood predominantly in terms of zero-lag temporal synchrony (functional connectivity) within systems known as resting state networks (RSNs). Prior rs-fMRI studies have found that RSNs are generally preserved across wake and sleep. Here, we use a recently developed analysis technique to study propagation of infra-slow intrinsic blood oxygen level dependent (BOLD) signals in normal adults during wake and SWS. This analysis reveals marked changes in propagation patterns in SWS vs. wake. Broadly, ordered propagation is preserved within traditionally defined RSNs but lost between RSNs. Additionally, propagation between cerebral cortex and subcortical structures reverses directions, and intra-cortical propagation becomes reorganized, especially in visual and sensorimotor cortices. These findings show that propagated rs-fMRI activity informs theoretical accounts of the neural functions of sleep.

  1. Activation of dorsolateral prefrontal cortex in a dual neuropsychological screening test: An fMRI approach

    PubMed Central

    2012-01-01

    Background The Kana Pick-out Test (KPT), which uses Kana or Japanese symbols that represent syllables, requires parallel processing of discrete (pick-out) and continuous (reading) dual tasks. As a dual task, the KPT is thought to test working memory and executive function, particularly in the prefrontal cortex (PFC), and is widely used in Japan as a clinical screen for dementia. Nevertheless, there has been little neurological investigation into PFC activity during this test. Methods We used functional magnetic resonance imaging (fMRI) to evaluate changes in the blood oxygenation level-dependent (BOLD) signal in young healthy adults during performance of a computerized KPT dual task (comprised of reading comprehension and picking out vowels) and compared it to its single task components (reading or vowel pick-out alone). Results Behavioral performance of the KPT degraded compared to its single task components. Performance of the KPT markedly increased BOLD signal intensity in the PFC, and also activated sensorimotor, parietal association, and visual cortex areas. In conjunction analyses, bilateral BOLD signal in the dorsolateral PFC (Brodmann's areas 45, 46) was present only in the KPT. Conclusions Our results support the central bottleneck theory and suggest that the dorsolateral PFC is an important mediator of neural activity for both short-term storage and executive processes. Quantitative evaluation of the KPT with fMRI in healthy adults is the first step towards understanding the effects of aging or cognitive impairment on KPT performance. PMID:22640773

  2. Activation of dorsolateral prefrontal cortex in a dual neuropsychological screening test: an fMRI approach.

    PubMed

    Tachibana, Atsumichi; Noah, J Adam; Bronner, Shaw; Ono, Yumie; Hirano, Yoshiyuki; Niwa, Masami; Watanabe, Kazuko; Onozuka, Minoru

    2012-05-28

    The Kana Pick-out Test (KPT), which uses Kana or Japanese symbols that represent syllables, requires parallel processing of discrete (pick-out) and continuous (reading) dual tasks. As a dual task, the KPT is thought to test working memory and executive function, particularly in the prefrontal cortex (PFC), and is widely used in Japan as a clinical screen for dementia. Nevertheless, there has been little neurological investigation into PFC activity during this test. We used functional magnetic resonance imaging (fMRI) to evaluate changes in the blood oxygenation level-dependent (BOLD) signal in young healthy adults during performance of a computerized KPT dual task (comprised of reading comprehension and picking out vowels) and compared it to its single task components (reading or vowel pick-out alone). Behavioral performance of the KPT degraded compared to its single task components. Performance of the KPT markedly increased BOLD signal intensity in the PFC, and also activated sensorimotor, parietal association, and visual cortex areas. In conjunction analyses, bilateral BOLD signal in the dorsolateral PFC (Brodmann's areas 45, 46) was present only in the KPT. Our results support the central bottleneck theory and suggest that the dorsolateral PFC is an important mediator of neural activity for both short-term storage and executive processes. Quantitative evaluation of the KPT with fMRI in healthy adults is the first step towards understanding the effects of aging or cognitive impairment on KPT performance.

  3. Carbamazepine reduces memory induced activation of mesial temporal lobe structures: a pharmacological fMRI-study

    PubMed Central

    Jokeit, Hennric; Okujava, Michael; Woermann, Friedrich G

    2001-01-01

    Background and Purpose It is not known whether carbamazepine (CBZ; a drug widely used in neurology and psychiatry) influences the blood oxygenation level dependent (BOLD) contrast changes induced by neuronal activation and measured by functional MRI (fMRI). We aimed to investigate the influence of CBZ on memory induced activation of the mesial temporal lobes in patients with symptomatic temporal lobe epilepsy (TLE). Material and Methods Twenty-one individual patients with refractory symptomatic TLE with different CBZ serum levels and 20 healthy controls were studied using BOLD fMRI. Mesial temporal lobe (MTL) activation was induced by a task that is based on the retrieval of individually familiar visuo-spatial knowledge. The extent of significant MTL fMRI activation was measured and correlated with the CBZ serum level. Results In TLE patients, the extent of significant fMRI activation over both MTL was negatively correlated to the CBZ serum level (Spearman r = -0.654, P < 0.001). Activation over the supposedly normal MTL, i.e. contralateral to the seizure onset of TLE patients, was smaller than the averaged MTL activation in healthy controls (P < 0.005). Age, duration of epilepsy, side of seizure onset, and intelligence were not correlated to the extent of the significant BOLD-response over both MTL in patients with TLE. Conclusions In TLE patients, carbamazepine reduces the fMRI-detectable changes within the mesial temporal lobes as induced by effortful memory retrieval. FMRI appears to be suitable to study the effects of chronic drug treatment in patients with epilepsy. PMID:11710962

  4. Adolescent binge drinking linked to abnormal spatial working memory brain activation: differential gender effects.

    PubMed

    Squeglia, Lindsay M; Schweinsburg, Alecia Dager; Pulido, Carmen; Tapert, Susan F

    2011-10-01

    Binge drinking is prevalent during adolescence, and its effect on neurocognitive development is of concern. In adult and adolescent populations, heavy substance use has been associated with decrements in cognitive functioning, particularly on tasks of spatial working memory (SWM). Characterizing the gender-specific influences of heavy episodic drinking on SWM may help elucidate the early functional consequences of drinking on adolescent brain functioning. Forty binge drinkers (13 females, 27 males) and 55 controls (24 females, 31 males), aged 16 to 19 years, completed neuropsychological testing, substance use interviews, and an SWM task during functional magnetic resonance imaging. Significant binge drinking status × gender interactions were found (p < 0.05) in 8 brain regions spanning bilateral frontal, anterior cingulate, temporal, and cerebellar cortices. In all regions, female binge drinkers showed less SWM activation than female controls, while male bingers exhibited greater SWM response than male controls. For female binge drinkers, less activation was associated with poorer sustained attention and working memory performances (p < 0.025). For male binge drinkers, greater activation was linked to better spatial performance (p < 0.025). Binge drinking during adolescence is associated with gender-specific differences in frontal, temporal, and cerebellar brain activation during an SWM task, which in turn relate to cognitive performance. Activation correlates with neuropsychological performance, strengthening the argument that blood oxygen level-dependent activation is affected by alcohol use and is an important indicator of behavioral functioning. Females may be more vulnerable to the neurotoxic effects of heavy alcohol use during adolescence, while males may be more resilient to the deleterious effects of binge drinking. Future longitudinal research will examine the significance of SWM brain activation as an early neurocognitive marker of alcohol impact to the

  5. Influence of BOLD Contributions to Diffusion fMRI Activation of the Visual Cortex

    PubMed Central

    Williams, Rebecca J.; Reutens, David C.; Hocking, Julia

    2016-01-01

    Reliance on the hemodynamic response as a surrogate marker of neural activity imposes an intrinsic limit on the spatial specificity of functional MRI. An alternative approach based on diffusion-weighted functional MRI (DfMRI) has been reported as a contrast less reliant on hemodynamic effects, however current evidence suggests that both hemodynamic and unique neural sources contribute to the diffusion signal. Here we compare activation patterns obtained with the standard blood oxygenation level-dependent (BOLD) contrast to DfMRI in order to gain a deeper understanding of how the BOLD proportion contributes to the observable diffusion signal. Both individual and group-level activation patterns obtained with DfMRI and BOLD to a visual field stimulation paradigm were analyzed. At the individual level, the DfMRI contrast showed a strong, positive relationship between the volumes of cortex activated in response to quadrant- and hemi-field visual stimulation. This was not observed in the corresponding BOLD experiment. Overall, the DfMRI response indicated less between-subject variability, with random effects analyses demonstrating higher statistical values at the peak voxel for DfMRI. Furthermore, the spatial extent of the activation was more restricted to the primary visual region for DfMRI than BOLD. However, the diffusion signal was sensitive to the hemodynamic response in a manner dependent on experimental manipulation. It was also limited by its low signal-to-noise ratio (SNR), demonstrating lower sensitivity than BOLD. Together these findings both support DfMRI as a contrast that bears a closer spatial relationship to the underlying neural activity than BOLD, and raise important caveats regarding its utilization. Models explaining the DfMRI signal change need to consider the dynamic vascular contributions that may vary with neural activity. PMID:27445654

  6. Differences in brain activation between tremor- and nontremor-dominant Parkinson disease.

    PubMed

    Prodoehl, Janey; Planetta, Peggy J; Kurani, Ajay S; Comella, Cynthia L; Corcos, Daniel M; Vaillancourt, David E

    2013-01-01

    OBJECTIVE To compare differences in functional brain activity between tremor- and nontremor-dominant subtypes of Parkinson disease (PD) using functional magnetic resonance imaging. DESIGN In our study, patients with tremor-dominant PD and those with nontremor-dominant PD performed a grip task, and the results obtained were compared using voxelwise analysis. Areas of the brain that were significantly different were then examined using a region-of-interest analysis to compare these patients with healthy controls. Voxel-based morphometry was used to determine macroscopic differences in gray and white matter volume between patient groups. SETTING University-affiliated research institution. PARTICIPANTS A total of 20 drug-naive patients with PD (10 with tremor-dominant PD and 10 with nontremor-dominant PD) and a total of 20 healthy controls. MAIN OUTCOME MEASURES Blood oxygenation level-dependent activation and percent signal change. RESULTS Robust findings across both voxelwise and region-of-interest analyses showed that, compared with patients with tremor-dominant PD, patients with nontremor-dominant PD had reduced activation in the ipsilateral dorsolateral prefrontal cortex, the globus pallidus interna, and the globus pallidus externa. Region-of-interest analyses confirmed that patients with nontremor-dominant PD had reduced activity in the ipsilateral dorsolateral prefrontal cortex, the globus pallidus interna, and the globus pallidus externa compared with patients with tremor-dominant PD and healthy controls. Patients with tremor-dominant PD had increased activity in the contralateral dorsolateral prefrontal cortex compared with patients with nontremor-dominant PD and healthy controls. These results could not be explained by differences in gray or white matter volume. CONCLUSIONS Reduced brain activity occurs in the prefrontal cortex and globus pallidus of patients with nontremor-dominant PD compared with both patients with tremor-dominant PD and healthy controls

  7. Changes in cue-induced, prefrontal cortex activity with video-game play.

    PubMed

    Han, Doug Hyun; Kim, Yang Soo; Lee, Yong Sik; Min, Kyung Joon; Renshaw, Perry F

    2010-12-01

    Brain responses, particularly within the orbitofrontal and cingulate cortices, to Internet video-game cues in college students are similar to those observed in patients with substance dependence in response to the substance-related cues. In this study, we report changes in brain activity between baseline and following 6 weeks of Internet video-game play. We hypothesized that subjects with high levels of self-reported craving for Internet video-game play would be associated with increased activity in the prefrontal cortex, particularly the orbitofrontal and anterior cingulate cortex. Twenty-one healthy university students were recruited. At baseline and after a 6-week period of Internet video-game play, brain activity during presentation of video-game cues was assessed using 3T blood oxygen level dependent functional magnetic resonance imaging. Craving for Internet video-game play was assessed by self-report on a 7-point visual analogue scale following cue presentation. During a standardized 6-week video-game play period, brain activity in the anterior cingulate and orbitofrontal cortex of the excessive Internet game-playing group (EIGP) increased in response to Internet video-game cues. In contrast, activity observed in the general player group (GP) was not changed or decreased. In addition, the change of craving for Internet video games was positively correlated with the change in activity of the anterior cingulate in all subjects. These changes in frontal-lobe activity with extended video-game play may be similar to those observed during the early stages of addiction.

  8. Decreased medial prefrontal cortex activation during self-referential processing in bipolar mania.

    PubMed

    Herold, Dorrit; Usnich, Tatiana; Spengler, Stephanie; Sajonz, Bastian; Bauer, Michael; Bermpohl, Felix

    2017-09-01

    Patients with bipolar disorder in mania exhibit symptoms pointing towards altered self-referential processing, such as decreased self-focus, flight of ideas and high distractibility. In depression, the opposite pattern of symptoms has been connected to increased activation of medial prefrontal cortex (mPFC) during self-referential processing. In this study, we hypothesized that (1) patients with mania will exhibit decreased activation in the mPFC during self-referential processing and (2) will be more alexithymic and that levels of alexithymia will correlate negatively with mPFC activation. The neural response to standardized pictures was compared in 14 patients with bipolar I disorder in mania to 14 healthy controls using blood oxygen level dependent contrast magnetic resonance imaging. Participants were asked to indicate with button press during the scanning session for each picture whether the pictures personally related to them or not. Toronto alexithymia scale (TAS) scores were recorded from all participants. In the group analysis, patients with mania exhibited decreased activation in a predefined region of interest in the mPFC during self-referential processing compared to healthy controls. Patients with mania showed significantly higher levels of alexithymia, attributable to difficulties in identifying and describing emotions. Activation in the mPFC correlated negatively with levels of alexithymia. Results presented here should be replicated in a larger group, potentially including unmedicated patients. The finding of decreased mPFC activation during self-referential processing in mania may reflect decreased self-focus and high distractibility. Support for this view comes from the negative correlation between higher alexithymia scores and decreased mPFC activation. These findings represent an opposite clinical and neuroimaging pattern to findings in depression. Copyright © 2017. Published by Elsevier B.V.

  9. An fMRI study of sex differences in regional activation to a verbal and a spatial task.

    PubMed

    Gur, R C; Alsop, D; Glahn, D; Petty, R; Swanson, C L; Maldjian, J A; Turetsky, B I; Detre, J A; Gee, J; Gur, R E

    2000-09-01

    Sex differences in cognitive performance have been documented, women performing better on some phonological tasks and men on spatial tasks. An earlier fMRI study suggested sex differences in distributed brain activation during phonological processing, with bilateral activation seen in women while men showed primarily left-lateralized activation. This blood oxygen level-dependent fMRI study examined sex differences (14 men, 13 women) in activation for a spatial task (judgment of line orientation) compared to a verbal-reasoning task (analogies) that does not typically show sex differences. Task difficulty was manipulated. Hypothesized ROI-based analysis documented the expected left-lateralized changes for the verbal task in the inferior parietal and planum temporal regions in both men and women, but only men showed right-lateralized increase for the spatial task in these regions. Image-based analysis revealed a distributed network of cortical regions activated by the tasks, which consisted of the lateral frontal, medial frontal, mid-temporal, occipitoparietal, and occipital regions. The activation was more left lateralized for the verbal and more right for the spatial tasks, but men also showed some left activation for the spatial task, which was not seen in women. Increased task difficulty produced more distributed activation for the verbal and more circumscribed activation for the spatial task. The results suggest that failure to activate the appropriate hemisphere in regions directly involved in task performance may explain certain sex differences in performance. They also extend, for a spatial task, the principle that bilateral activation in a distributed cognitive system underlies sex differences in performance. Copyright 2000 Academic Press.

  10. Quinolone activity against anaerobes.

    PubMed

    Appelbaum, P C

    1999-01-01

    The first generation of fluoroquinolones such as ciprofloxacin and ofloxacin are inactive against most anaerobic bacteria. However, some broad-spectrum quinolones, which have recently become clinically available or are under active development, have significant antianaerobic activity. This review summarises the in vitro activity of currently available, as well as experimental, quinolones against clinically significant anaerobic bacteria. Quinolones with low activity against anaerobes include ciprofloxacin, ofloxacin, levofloxacin, fleroxacin, pefloxacin, enoxacin and lomefloxacin. Compounds with intermediate antianaerobic activity include sparfloxacin and grepafloxacin. Trovafloxacin, gatifloxacin and moxifloxacin yield low MICs against most groups of anaerobes. Quinolones with the greatest in vitro activity against anaerobes include clinafloxacin and sitafloxacin (DU-6859a).

  11. Cultural Activation of Consumers.

    PubMed

    Siegel, Carole E; Reid-Rose, Lenora; Joseph, Adriana M; Hernandez, Jennifer C; Haugland, Gary

    2016-02-01

    This column discusses "cultural activation," defined as a consumer's recognition of the importance of providing cultural information to providers about cultural affiliations, challenges, views about, and attitudes toward behavioral health and general medical health care, as well as the consumer's confidence in his or her ability to provide this information. An aid to activation, "Cultural Activation Prompts," and a scale that measures a consumer's level of activation, the Cultural Activation Measurement Scale, are described. Suggestions are made about ways to introduce cultural activation as a component of usual care.

  12. CATALASE ACTIVITY IN LEPTOSPIRA

    PubMed Central

    Rao, P. J.; Larson, A. D.; Cox, C. D.

    1964-01-01

    Rao, P. J. (University of Illinois, Urbana), A. D. Larson, and C. D. Cox. Catalase activity in Leptospira. J. Bacteriol. 88:1045–1048. 1964.—A number of serotypes of Leptospira were found to possess catalase activity, although considerable variation in activity existed among various serotypes. Catalase activity of L. pomona was reduced by inhibitors commonly employed for arresting catalase activity in other biological systems. Catalase activity was increased three to five times by growing cultures under conditions of oxygen availability; however, aeration had no beneficial effect on total viable cell crop. The relationship of oxygen to metabolism and future studies on virulence of the leptospirae is discussed. PMID:14219017

  13. Smoking, physical activity, and active life expectancy.

    PubMed

    Ferrucci, L; Izmirlian, G; Leveille, S; Phillips, C L; Corti, M C; Brock, D B; Guralnik, J M

    1999-04-01

    The effect of smoking and physical activity on active and disabled life expectancy was estimated using data from the Established Populations for Epidemiologic Studies of the Elderly (EPESE). Population-based samples of persons aged > or = 65 years from the East Boston, Massachusetts, New Haven, Connecticut, and Iowa sites of the EPESE were assessed at baseline between 1981 and 1983 and followed for mortality and disability over six annual follow-ups. A total of 8,604 persons without disability at baseline were classified as "ever" or "never" smokers and doing "low," "moderate," or "high" level physical activity. Active and disabled life expectancies were estimated using a Markov chain model. Compared with smokers, men and women nonsmokers survived 1.6-3.9 and 1.6-3.6 years longer, respectively, depending on level of physical activity. When smokers were disabled and close to death, most nonsmokers were still nondisabled. Physical activity, from low to moderate to high, was significantly associated with more years of life expectancy in both smokers (9.5, 10.5, 12.9 years in men and 11.1, 12.6, 15.3 years in women at age 65) and nonsmokers (11.0, 14.4, 16.2 years in men and 12.7, 16.2, 18.4 years in women at age 65). Higher physical activity was associated with fewer years of disability prior to death. These findings provide strong and explicit evidence that refraining from smoking and doing regular physical activity predict a long and healthy life.

  14. Cortical activation by tactile stimulation to face and anterior neck areas: an fMRI study with three analytic methods.

    PubMed

    Lin, Chou-Ching K; Sun, Yung-Nien; Huang, Chung-I; Yu, Chin-Yin; Ju, Ming-Shaung

    2010-12-01

    The main purpose of this study was to investigate the sensory cortical activation of the anterior neck region and the relationship between the neck and face representation areas. Functional MRI by blood oxygenation level dependent measurements was performed while tactile stimulation was applied to the face or neck area. Nonpainful tactile stimuli were manually delivered by an experimenter at a frequency of ∼1 Hz. Block (epoch) design was adopted with a block duration of 30 s and a whole run duration of 6 min. For each location, two runs were performed. After the image data were preprocessed, both parameteric and nonparametric methods were performed to test the group results. The results showed that (1) unilateral face or neck stimulation could elicit bilateral cortical activation, (2) mainly the face representation and face-hand junction areas, but not the conventional neck representation area, were activated by face or neck stimulation, and (3) the activation areas were larger when right face or neck was stimulated. In conclusion, the sensory cortical representation area of the anterior neck region was mainly at the junction of hand and face representation area and the activated area was larger when the right face or neck was stimulated.

  15. Increased Intrinsic Activity of Medial-Temporal Lobe Subregions is Associated with Decreased Cortical Thickness of Medial-Parietal Areas in Patients with Alzheimer's Disease Dementia.

    PubMed

    Pasquini, Lorenzo; Scherr, Martin; Tahmasian, Masoud; Myers, Nicholas E; Ortner, Marion; Kurz, Alexander; Förstl, Hans; Zimmer, Claus; Grimmer, Timo; Akhrif, Atae; Wohlschläger, Afra M; Riedl, Valentin; Sorg, Christian

    2016-01-01

    In Alzheimer's disease (AD), disrupted connectivity between medial-parietal cortices and medial-temporal lobes (MTL) is linked with increased MTL local functional connectivity, and parietal atrophy is associated with increased MTL memory activation. We hypothesized that intrinsic activity in MTL subregions is increased and associated with medial-parietal degeneration and impaired memory in AD. To test this hypothesis, resting-state-functional and structural-MRI was assessed in 22 healthy controls, 22 mild cognitive impairment patients, and 21 AD-dementia patients. Intrinsic activity was measured by power-spectrum density of blood-oxygenation-level-dependent signal, medial-parietal degeneration by cortical thinning. In AD-dementia patients, intrinsic activity was increased for several right MTL subregions. Raised intrinsic activity in dentate gyrus and cornu ammonis 1 was associated with cortical thinning in posterior cingulate cortices, and at-trend with impaired delayed recall. Critically, increased intrinsic activity in the right entorhinal cortex was associated with ipsilateral posterior cingulate degeneration. Our results provide evidence that in AD, intrinsic activity in MTL subregions is increased and associated with medial-parietal atrophy. Results fit a model in which medial-parietal degeneration contributes to MTL dysconnectivity from medial-parietal cortices, potentially underpinning disinhibition-like changes in MTL activity.

  16. Obesity and physical activity.

    PubMed

    Jakicic, John M; Davis, Kelliann K

    2011-12-01

    Physical activity seems to be an important component of lifestyle interventions for weight loss and maintenance. Although the effects of physical activity on weight loss may seem to be modest, there seems to be a dose-response relationship between physical activity and weight loss. Physical activity also seems to be a critically important behavior to promote long-term weight loss and the prevention of weight regain. The benefits of physical activity on weight loss are also observed in patients with severe obesity (BMI ≥ 35 kg/m²) and in patients who have undergone bariatric surgery. Moreover, independent of the effect of physical activity on body weight, engagement in physical activity that results in improved cardiorespiratory fitness can contribute to reductions in health risk in overweight and obese adults. Thus, progression of overweight and obese patients to an adequate dose of physical activity needs to be incorporated into clinical interventions for weight control.

  17. Major operations and activities

    SciTech Connect

    Black, D.G.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the major operations and activities on the site. These operations and activities include site management, waste management, environmental restoration and corrective actions, and research and technology development.

  18. Osmosis with active solutes

    NASA Astrophysics Data System (ADS)

    Lion, Thomas W.; Allen, Rosalind J.

    2014-05-01

    Despite much current interest in active matter, little is known about osmosis in active systems. Using molecular dynamics simulations, we investigate how active solutes perturb osmotic steady states. We find that solute activity increases the osmotic pressure, and can also expel solvent from the solution —i.e. cause reverse osmosis. The latter effect cannot be described by an effective temperature, but can be reproduced by mapping the active solution onto a passive one with the same degree of local structuring as the passive solvent component. Our results provide a basic framework for understanding active osmosis, and suggest that activity-induced structuring of the passive component may play a key role in the physics of active-passive mixtures.

  19. Family Activities for Fitness

    ERIC Educational Resources Information Center

    Grosse, Susan J.

    2009-01-01

    This article discusses how families can increase family togetherness and improve physical fitness. The author provides easy ways to implement family friendly activities for improving and maintaining physical health. These activities include: walking, backyard games, and fitness challenges.

  20. Family Activities for Fitness

    ERIC Educational Resources Information Center

    Grosse, Susan J.

    2009-01-01

    This article discusses how families can increase family togetherness and improve physical fitness. The author provides easy ways to implement family friendly activities for improving and maintaining physical health. These activities include: walking, backyard games, and fitness challenges.

  1. Population Education. Awareness Activities.

    ERIC Educational Resources Information Center

    Brouse, Deborah E.

    1990-01-01

    Described are awareness activities that deal with human population growth, resources, and the environment. Activities include simulations, mathematical exercises, and discussions of the topic. Specific examples of what individuals can do to help are listed. (KR)

  2. Activities for Calculators.

    ERIC Educational Resources Information Center

    Hiatt, Arthur A.

    1987-01-01

    Ten activities that give learners in grades 5-8 a chance to explore mathematics with calculators are provided. The activity cards involve such topics as odd addends, magic squares, strange projects, and conjecturing rules. (MNS)

  3. Active magnetic regenerator

    DOEpatents

    Barclay, John A.; Steyert, William A.

    1982-01-01

    The disclosure is directed to an active magnetic regenerator apparatus and method. Brayton, Stirling, Ericsson, and Carnot cycles and the like may be utilized in an active magnetic regenerator to provide efficient refrigeration over relatively large temperature ranges.

  4. ACS Community Activities Contests

    NASA Astrophysics Data System (ADS)

    Burgener, Marisa

    2007-08-01

    The Committee on Community Activities and the Office of Community Activities announce the winners of the Illustrated Haiku Contest, Earth Day 2007 and the Poster Contest, National Chemistry Week 2006.

  5. Woodsy Owl Activity Guide.

    ERIC Educational Resources Information Center

    Forest Service (USDA), Washington, DC.

    This guide offers teachers and after-school group leaders 12 fun and engaging activities. Activities feature lessons on trees, water, wind, the earth, food, and waste. The activities are designed to help children aged 5-8 become more aware of the natural environment and fundamental conservation principles. Titles of children's books are embedded…

  6. Activity Theory and Ontology

    ERIC Educational Resources Information Center

    Peim, Nick

    2009-01-01

    This paper seeks to re-examine Yrio Engestrom's activity theory as a technology of knowledge designed to enable positive transformations of specific practices. The paper focuses on a key paper where Engestrom defines the nature and present state of activity theory. Beginning with a brief account of the relations between activity theory and…

  7. Technology Learning Activities I.

    ERIC Educational Resources Information Center

    International Technology Education Association, Reston, VA.

    This guide contains 30 technology learning activities. Activities may contain all or some of the following: an introduction, objectives, materials and equipment, challenges, limitations, notes and investigations, resources and references used, and evaluation ideas. Activity titles are: (1) Occupations in Construction Technology; (2) Designing a…

  8. Climate Change: An Activity.

    ERIC Educational Resources Information Center

    Lewis, Garry

    1995-01-01

    Presents a segment of the Geoscience Education booklet, Climate Change, that contains information and activities that enable students to gain a better appreciation of the possible effects human activity has on the Earth's climate. Describes the Terrace Temperatures activity that leads students through an investigation using foraminifera data to…

  9. Activity Sheets. Draft Copy.

    ERIC Educational Resources Information Center

    Duke Power Company, Educational Services Dept., Charlotte, NC.

    This document consists of energy vocabulary activities, three games, worksheets, laboratory activities/exercises, and an introductory classroom exercise designed to introduce energy concepts to students. Vocabulary activities focus on coal and energy consumption. The three games (with instructions) focus on various aspects of energy and energy…

  10. Imagery: Activity Guide.

    ERIC Educational Resources Information Center

    Acton, Karen; Griffith, Judy

    An activity unit for teaching students to identify and use imagery in writing is presented. Instructions to the teacher for introducing the unit are given along with a list of student objectives and definitions of imagery terms. The activities, some of which involve using locally available audiovisual media, include four introductory activities,…

  11. FL Activities & Festivals.

    ERIC Educational Resources Information Center

    American Council on the Teaching of Foreign Languages, Hastings-on-Hudson, NY.

    A collection of student, class, and school foreign language activities suggests a variety of projects and describes three specific school efforts. The suggested activities include: (1) individual student efforts such as writing to pen-pals; (2) group activities such as a foreign language auction or sing-along; (3) group projects for the school…

  12. Measurement of Physical Activity.

    ERIC Educational Resources Information Center

    Dishman, Rod K.; Washburn, Richard A.; Schoeller, Dale A.

    2001-01-01

    Valid assessment of physical activity must be unobtrusive, practical to administer, and specific about physical activity type, frequency, duration, and intensity. Assessment methods can be categorized according to whether they provide direct or indirect (e.g., self-report) observation of physical activity, body motion, physiological response…

  13. Bonus Activity Book.

    ERIC Educational Resources Information Center

    Learning, 1992

    1992-01-01

    Provides on-task activities to fill in unexpected extra moments in elementary classes. The activities require little preparation and take 5-15 minutes to complete. There are activities for math, language arts, social science, science, critical thinking, and computer. An outer space board game is also included. (SM)

  14. Technology Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Brame, Ray; And Others

    This guide contains 43 modules of laboratory activities for technology education courses. Each module includes an instructor's resource sheet and the student laboratory activity. Instructor's resource sheets include some or all of the following elements: module number, course title, activity topic, estimated time, essential elements, objectives,…

  15. Highlights of 1981 activities

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The highlights of NASA's 1981 activities are presented, including the results of the two flights of the space shuttle Columbia and the Voyager 2 encounter with Saturn. Accomplishments in the areas of space transportation operations; space science; aeronautical, energy, and space research and development; as well as space tracking, international activities, and 1981 launch activities are discussed.

  16. Activity Sheets. Draft Copy.

    ERIC Educational Resources Information Center

    Duke Power Company, Educational Services Dept., Charlotte, NC.

    This document consists of energy vocabulary activities, three games, worksheets, laboratory activities/exercises, and an introductory classroom exercise designed to introduce energy concepts to students. Vocabulary activities focus on coal and energy consumption. The three games (with instructions) focus on various aspects of energy and energy…

  17. Climate Change: An Activity.

    ERIC Educational Resources Information Center

    Lewis, Garry

    1995-01-01

    Presents a segment of the Geoscience Education booklet, Climate Change, that contains information and activities that enable students to gain a better appreciation of the possible effects human activity has on the Earth's climate. Describes the Terrace Temperatures activity that leads students through an investigation using foraminifera data to…

  18. Horticultural Practices. Activity Guides.

    ERIC Educational Resources Information Center

    Bania, Kent; Cummings, John, Ed.

    The 88 activity guides in this document are intended to supplement the initial or organized instruction of the agricultural teacher at the secondary educational level. Some of the activities require one student to complete, others may need two or more students working in a team. Some activities also require followup checking within a few days to…

  19. Activity Theory and Ontology

    ERIC Educational Resources Information Center

    Peim, Nick

    2009-01-01

    This paper seeks to re-examine Yrio Engestrom's activity theory as a technology of knowledge designed to enable positive transformations of specific practices. The paper focuses on a key paper where Engestrom defines the nature and present state of activity theory. Beginning with a brief account of the relations between activity theory and…

  20. Computers + Student Activities Handbook.

    ERIC Educational Resources Information Center

    Masie, Elliott; Stein, Michele

    Designed to provide schools with the tools to start utilizing computers for student activity programs without additional expenditures, this handbook provides beginning computer users with suggestions and ideas for using computers in such activities as drama clubs, yearbooks, newspapers, activity calendars, accounting programs, room utilization,…

  1. Technology Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Brame, Ray; And Others

    This guide contains 43 modules of laboratory activities for technology education courses. Each module includes an instructor's resource sheet and the student laboratory activity. Instructor's resource sheets include some or all of the following elements: module number, course title, activity topic, estimated time, essential elements, objectives,…

  2. Green Schools Activity Booklet.

    ERIC Educational Resources Information Center

    Sacramento Tree Foundation, CA.

    This collection of interdisciplinary hands-on activities covers a variety of topics related to trees and conservation. Twenty-four activities integrate the subjects of social studies, fine arts, science, language arts, math, geography, and music. Although activity instructions are not consistent they usually contain details on objectives and…

  3. Modeling Patterns of Activities using Activity Curves.

    PubMed

    Dawadi, Prafulla N; Cook, Diane J; Schmitter-Edgecombe, Maureen

    2016-06-01

    Pervasive computing offers an unprecedented opportunity to unobtrusively monitor behavior and use the large amount of collected data to perform analysis of activity-based behavioral patterns. In this paper, we introduce the notion of an activity curve, which represents an abstraction of an individual's normal daily routine based on automatically-recognized activities. We propose methods to detect changes in behavioral routines by comparing activity curves and use these changes to analyze the possibility of changes in cognitive or physical health. We demonstrate our model and evaluate our change detection approach using a longitudinal smart home sensor dataset collected from 18 smart homes with older adult residents. Finally, we demonstrate how big data-based pervasive analytics such as activity curve-based change detection can be used to perform functional health assessment. Our evaluation indicates that correlations do exist between behavior and health changes and that these changes can be automatically detected using smart homes, machine learning, and big data-based pervasive analytics.

  4. Modeling Patterns of Activities using Activity Curves

    PubMed Central

    Dawadi, Prafulla N.; Cook, Diane J.; Schmitter-Edgecombe, Maureen

    2016-01-01

    Pervasive computing offers an unprecedented opportunity to unobtrusively monitor behavior and use the large amount of collected data to perform analysis of activity-based behavioral patterns. In this paper, we introduce the notion of an activity curve, which represents an abstraction of an individual’s normal daily routine based on automatically-recognized activities. We propose methods to detect changes in behavioral routines by comparing activity curves and use these changes to analyze the possibility of changes in cognitive or physical health. We demonstrate our model and evaluate our change detection approach using a longitudinal smart home sensor dataset collected from 18 smart homes with older adult residents. Finally, we demonstrate how big data-based pervasive analytics such as activity curve-based change detection can be used to perform functional health assessment. Our evaluation indicates that correlations do exist between behavior and health changes and that these changes can be automatically detected using smart homes, machine learning, and big data-based pervasive analytics. PMID:27346990

  5. Neurofeedback fMRI-mediated learning and consolidation of regional brain activation during motor imagery

    PubMed Central

    Yoo, Seung-Schik; Lee, Jong-Hwan; O’Leary, Heather; Panych, Lawrence P.; Jolesz, Ferenc A.

    2009-01-01

    We report the long-term effect of real-time functional MRI (rtfMRI) training on voluntary regulation of the level of activation from a hand motor area. During the performance of a motor imagery task of a right hand, blood-oxygenation-level-dependent (BOLD) signal originating from a primary motor area was presented back to the subject in real-time. Demographically matched individuals also received the same procedure without valid feedback information. Followed by the initial rtfMRI sessions, both groups underwent two-week long, daily-practice of the task. Off-line data analysis revealed that the individuals in the experimental group were able to increase the level of BOLD signal from the regulatory target to a greater degree compared to the control group. Furthermore, the learned level of activation was maintained after the two-week period, with the recruitment of additional neural circuitries such as the hippocampus and the limbo-thalamo-cortical pathway. The activation obtained from the control group, in the absence of proper feedback, was indifferent across the training conditions. The level of BOLD activity from the target regulatory region was positively correlated with a self evaluative score within the experimental group, while the majority of control subjects had difficulty adopting a strategy to attain the desired level of functional regulation. Our results suggest that rtfMRI helped individuals learn how to increase region-specific cortical activity associated with a motor imagery task, and the level of increased activation in motor areas was consolidated after the two-week self-practice period, with the involvement of neural circuitries implicated in motor skill learning. PMID:19526048

  6. Abnormal activation of the motor cortical network in idiopathic scoliosis demonstrated by functional MRI.

    PubMed

    Domenech, Julio; García-Martí, G; Martí-Bonmatí, L; Barrios, C; Tormos, J M; Pascual-Leone, A

    2011-07-01

    The aetiology of idiopathic scoliosis (IS) remains unknown, but there is growing support for the possibility of an underlying neurological disorder. Functional magnetic resonance imaging (fMRI) can characterize the abnormal activation of the sensorimotor brain network in movement disorders and could provide further insights into the neuropathogenesis of IS. Twenty subjects were included in the study; 10 adolescents with IS (mean age of 15.2, 8 girls and 2 boys) and 10 age-matched healthy controls. The average Cobb angle of the primary curve in the IS patients was 35° (range 27°-55°). All participants underwent a block-design fMRI experiment in a 1.5-Tesla MRI scanner to explore cortical activation following a simple motor task. Rest periods alternated with activation periods during which participants were required to open and close their hand at an internally paced rate of approximately 1 Hz. Data were analyzed with Statistical Parametric Mapping (SPM5) including age, sex and laterality as nuisance variables to minimise the presence of bias in the results. Compared to controls, IS patients showed significant increases in blood oxygenation level dependent (BOLD) activity in contralateral supplementary motor area when performing the motor task with either hand. No significant differences were observed when testing between groups in the functional activation in the primary motor cortex, premotor cortex and somatosensory cortex. Additionally, the IS group showed a greater interhemispheric asymmetry index than the control group (0.30 vs. 0.13, p < 0.001). This study demonstrates an abnormal pattern of brain activation in secondary motor areas during movement execution in patients with IS. These findings support the hypothesis that a sensorimotor integration disorder underlies the pathogenesis of IS.

  7. Food and drug cues activate similar brain regions: a meta-analysis of functional MRI studies.

    PubMed

    Tang, D W; Fellows, L K; Small, D M; Dagher, A

    2012-06-06

    In healthy individuals, food cues can trigger hunger and feeding behavior. Likewise, smoking cues can trigger craving and relapse in smokers. Brain imaging studies report that structures involved in appetitive behaviors and reward, notably the insula, striatum, amygdala and orbital frontal cortex, tend to be activated by both visual food and smoking cues. Here, by carrying out a meta-analysis of human neuro-imaging studies, we investigate the neural network activated by: 1) food versus neutral cues (14 studies, 142 foci) 2) smoking versus neutral cues (15 studies, 176 foci) 3) smoking versus neutral cues when correlated with craving scores (7 studies, 108 foci). PubMed was used to identify cue-reactivity imaging studies that compared brain response to visual food or smoking cues to neutral cues. Fourteen articles were identified for the food meta-analysis and fifteen articles were identified for the smoking meta-analysis. Six articles were identified for the smoking cue correlated with craving analysis. Meta-analyses were carried out using activation likelihood estimation. Food cues were associated with increased blood oxygen level dependent (BOLD) response in the left amygdala, bilateral insula, bilateral orbital frontal cortex, and striatum. Smoking cues were associated with increased BOLD signal in the same areas, with the exception of the insula. However, the smoking meta-analysis of brain maps correlating cue-reactivity with subjective craving did identify the insula, suggesting that insula activation is only found when craving levels are high. The brain areas identified here are involved in learning, memory and motivation, and their cue-induced activity is an index of the incentive salience of the cues. Using meta-analytic techniques to combine a series of studies, we found that food and smoking cues activate comparable brain networks. There is significant overlap in brain regions responding to conditioned cues associated with natural and drug rewards.

  8. Computing moment-to-moment BOLD activation for real-time neurofeedback.

    PubMed

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

    2011-01-01

    Estimating moment-to-moment changes in blood oxygenation level dependent (BOLD) activation levels from functional magnetic resonance imaging (fMRI) data has applications for learned regulation of regional activation, brain state monitoring, and brain-machine interfaces. In each of these contexts, accurate estimation of the BOLD signal in as little time as possible is desired. This is a challenging problem due to the low signal-to-noise ratio of fMRI data. Previous methods for real-time fMRI analysis have either sacrificed the ability to compute moment-to-moment activation changes by averaging several acquisitions into a single activation estimate or have sacrificed accuracy by failing to account for prominent sources of noise in the fMRI signal. Here we present a new method for computing the amount of activation present in a single fMRI acquisition that separates moment-to-moment changes in the fMRI signal intensity attributable to neural sources from those due to noise, resulting in a feedback signal more reflective of neural activation. This method computes an incremental general linear model fit to the fMRI time series, which is used to calculate the expected signal intensity at each new acquisition. The difference between the measured intensity and the expected intensity is scaled by the variance of the estimator in order to transform this residual difference into a statistic. Both synthetic and real data were used to validate this method and compare it to the only other published real-time fMRI method. Copyright © 2010 Elsevier Inc. All rights reserved.

  9. Altered Cingulate and Insular Cortex Activation During Risk-Taking in Methamphetamine Dependence: Losses Lose Impact

    PubMed Central

    Gowin, Joshua L.; Stewart, Jennifer L.; May, April C.; Ball, Tali M.; Wittmann, Marc; Tapert, Susan F.; Paulus, Martin P.

    2013-01-01

    Aims To determine if methamphetamine-dependent (MD) individuals exhibit behavioral or neural processing differences in risk-taking relative to healthy comparison participants (CTL). Design This was a cross-sectional study comparing two groups’ behavior on a risk-taking task and neural processing as assessed using functional magnetic resonance imaging (fMRI). Settings The study was conducted in an inpatient treatment center and a research fMRI facility in the United States. Participants Sixty-eight recently abstinent MD individuals recruited from a treatment program and forty CTL recruited from the community completed the study. Measurements The study assessed risk-taking behavior (overall and post-loss) using the Risky Gains Task (RGT), sensation-seeking, impulsivity and blood-oxygenation level dependent activation in the brain during the decision phase of the RGT. Findings Relative to CTL, MD displayed decreased activation in the bilateral rostral anterior cingulate cortex (ACC) and greater activation in the left insula across risky and safe decisions (p<.05). Right mid insula activation among CTL did not vary between risky and safe decisions, but among MD it was higher during risky relative to safe decisions (p<.05). Among MD, lower activation in the right rostral ACC (r=−.39, p<.01) and higher activation in the right mid insula (r=.35, p<.01) during risky decisions were linked to a higher likelihood of choosing a risky option following a loss. Conclusions Methamphetamine-dependent individuals show disrupted risk-related processing in both anterior cingulate and insula, brain areas that have been implicated in cognitive control and interoceptive processing. Attenuated neural processing of risky options may lead to risk-taking despite experiencing negative consequences. PMID:24033715

  10. Proteolytic activities in yeast.

    PubMed

    Saheki, T; Holzer, H

    1975-03-28

    Studies on the mechanism and time course of the activation of proteinases A (EC 3.4.23.8), B (EC 3.4.22.9) and C (EC 3.4.12.--) in crude yeast extracts at pH 5.1 and 25 degrees C showed that the increase in proteinase B activity is paralleled with the disappearance of proteinase B inhibitor. Addition of purified proteinase A to fresh crude extracts accelerates the inactivation of the proteinase B inhibitor and the appearance of maximal activities of proteinases B and C. The decrease of proteinase B inhibitor activity and the increase of proteinase B activity are markedly retarded by the addition of pepstatin. Because 10-minus 7 M pepstatin completely inhibits proteinase A without affecting proteinase B activity, this is another indication for the role of proteinase A during the activation of proteinase B. Whereas extracts of yeast grown on minimal medium reached maximal activation of proteinases B and C after 20 h of incubation at pH 5.1 and 25 degrees C, extracts of yeast grown on complete medium had to be incubated for about 100 h. In the latter case, the addition of proteinas A results in maximal activation of proteinases B and C and disappearance of proteinase B inhibitor activity only after 10--20 h of incubation. With the optimal conditions, the maximal activities of proteinases A, B and C, as well as of the proteinase B inhibitor, were determined in crude extracts of yeast that had been grown batchwise for different lengths of time either on minimal or on complete medium. Upon incubation, all three proteinases were activated by several times their initial activity. This reflects the existence of proteolytically degradable inhibitors of the three proteinases and together with the above mentioned observations it demonstrates that the "activation" of yeast proteinases A, B and C upon incubation results from the proteolytic digestion of inhibitors rather than from activation of inactive zymogens by limited proteolysis.

  11. Tea enhances insulin activity.

    PubMed

    Anderson, Richard A; Polansky, Marilyn M

    2002-11-20

    The most widely known health benefits of tea relate to the polyphenols as the principal active ingredients in protection against oxidative damage and in antibacterial, antiviral, anticarcinogenic, and antimutagenic activities, but polyphenols in tea may also increase insulin activity. The objective of this study was to determine the insulin-enhancing properties of tea and its components. Tea, as normally consumed, was shown to increase insulin activity >15-fold in vitro in an epididymal fat cell assay. Black, green, and oolong teas but not herbal teas, which are not teas in the traditional sense because they do not contain leaves of Camellia senensis, were all shown to increase insulin activity. High-performance liquid chromatography fractionation of tea extracts utilizing a Waters SymmetryPrep C18 column showed that the majority of the insulin-potentiating activity for green and oolong teas was due to epigallocatechin gallate. For black tea, the activity was present in several regions of the chromatogram corresponding to, in addition to epigallocatechin gallate, tannins, theaflavins, and other undefined compounds. Several known compounds found in tea were shown to enhance insulin with the greatest activity due to epigallocatechin gallate followed by epicatechin gallate, tannins, and theaflavins. Caffeine, catechin, and epicatechin displayed insignificant insulin-enhancing activities. Addition of lemon to the tea did not affect the insulin-potentiating activity. Addition of 5 g of 2% milk per cup decreased the insulin-potentiating activity one-third, and addition of 50 g of milk per cup decreased the insulin-potentiating activity approximately 90%. Nondairy creamers and soy milk also decreased the insulin-enhancing activity. These data demonstrate that tea contains in vitro insulin-enhancing activity and the predominant active ingredient is epigallocatechin gallate.

  12. Vestibular activation of sympathetic nerve activity

    NASA Technical Reports Server (NTRS)

    Ray, C. A.; Carter, J. R.

    2003-01-01

    AIM: The vestibulosympathetic reflex refers to sympathetic nerve activation by the vestibular system. Animal studies indicate that the vestibular system assists in blood pressure regulation during orthostasis. Although human studies clearly demonstrate activation of muscle sympathetic nerve activity (MSNA) during engagement of the otolith organs, the role of the vestibulosympathetic reflex in maintaining blood pressure during orthostasis is not well-established. Examination of the vestibulosympathetic reflex with other cardiovascular reflexes indicates that it is a powerful and independent reflex. Ageing, which is associated with an increased risk for orthostatic hypotension, attenuates the vestibulosympathetic reflex. The attenuated reflex is associated with a reduction in arterial pressure. CONCLUSION: These findings suggest that the vestibulosympathetic reflex assists in blood pressure regulation in humans, but future studies examining this reflex in other orthostatically intolerant populations are necessary to address this hypothesis.

  13. Vestibular activation of sympathetic nerve activity

    NASA Technical Reports Server (NTRS)

    Ray, C. A.; Carter, J. R.

    2003-01-01

    AIM: The vestibulosympathetic reflex refers to sympathetic nerve activation by the vestibular system. Animal studies indicate that the vestibular system assists in blood pressure regulation during orthostasis. Although human studies clearly demonstrate activation of muscle sympathetic nerve activity (MSNA) during engagement of the otolith organs, the role of the vestibulosympathetic reflex in maintaining blood pressure during orthostasis is not well-established. Examination of the vestibulosympathetic reflex with other cardiovascular reflexes indicates that it is a powerful and independent reflex. Ageing, which is associated with an increased risk for orthostatic hypotension, attenuates the vestibulosympathetic reflex. The attenuated reflex is associated with a reduction in arterial pressure. CONCLUSION: These findings suggest that the vestibulosympathetic reflex assists in blood pressure regulation in humans, but future studies examining this reflex in other orthostatically intolerant populations are necessary to address this hypothesis.

  14. Metabolism Supports Macrophage Activation

    PubMed Central

    Langston, P. Kent; Shibata, Munehiko; Horng, Tiffany

    2017-01-01

    Macrophages are found in most tissues of the body, where they have tissue- and context-dependent roles in maintaining homeostasis as well as coordinating adaptive responses to various stresses. Their capacity for specialized functions is controlled by polarizing signals, which activate macrophages by upregulating transcriptional programs that encode distinct effector functions. An important conceptual advance in the field of macrophage biology, emerging from recent studies, is that macrophage activation is critically supported by metabolic shifts. Metabolic shifts fuel multiple aspects of macrophage activation, and preventing these shifts impairs appropriate activation. These findings raise the exciting possibility that macrophage functions in various contexts could be regulated by manipulating their metabolism. Here, we review the rapidly evolving field of macrophage metabolism, discussing how polarizing signals trigger metabolic shifts and how these shifts enable appropriate activation and sustain effector activities. We also discuss recent studies indicating that the mitochondria are central hubs in inflammatory macrophage activation. PMID:28197151

  15. Comparable fMRI activity with differential behavioural performance on mental rotation and overt verbal fluency tasks in healthy men and women.

    PubMed

    Halari, Rozmin; Sharma, Tonmoy; Hines, Melissa; Andrew, Chris; Simmons, Andy; Kumari, Veena

    2006-02-01

    To explicate the neural correlates of sex differences in visuospatial and verbal fluency tasks, we examined behavioural performance and blood-oxygenation-level-dependent (BOLD) regional brain activity, using functional magnetic resonance imaging, during a three-dimensional (3D) mental rotation task and a compressed sequence overt verbal fluency task in a group of healthy men (n=9) and women (n=10; tested during the low-oestrogen phase of the menstrual cycle). Men outperformed women on the mental rotation task, and women outperformed men on the verbal fluency task. For the mental rotation task, men and women activated areas in the right superior parietal lobe and the bilateral middle occipital gyrus in association with the rotation condition. In addition, men activated the left middle temporal gyrus and the right angular gyrus. For verbal fluency, men activated areas in the bilateral superior frontal gyrus, right cingulate gyrus, left precentral gyrus, left medial frontal gyrus, left inferior frontal gyrus, thalamus, left parahippocampal gyrus and bilateral lingual gyrus, and women activated areas in the bilateral inferior frontal gyrus and left caudate. Despite observing task related activation in the hypothesised areas in men and women, no areas significantly differentiated the two sexes. Our results demonstrate comparable brain activation in men and women in association with mental rotation and verbal fluency function with differential performance, and provide support for sex differences in brain-behaviour relationships.

  16. Stimulation-induced transient changes in neuronal activity, blood flow and N-acetylaspartate content in rat prefrontal cortex: a chemogenetic fMRS-BOLD study.

    PubMed

    Baslow, Morris H; Cain, Christopher K; Sears, Robert; Wilson, Donald A; Bachman, Alvin; Gerum, Scott; Guilfoyle, David N

    2016-12-01

    Brain activation studies in humans have shown the dynamic nature of neuronal N-acetylaspartate (NAA) and N-acetylaspartylglutamate (NAAG) based on changes in their MRS signals in response to stimulation. These studies demonstrated that upon visual stimulation there was a focal increase in cerebral blood flow (CBF) and a decrease in NAA or in the total of NAA and NAAG signals in the visual cortex, and that these changes were reversed upon cessation of stimulation. In the present study we have developed an animal model in order to explore the relationships between brain stimulation, neuronal activity, CBF and NAA. We use "designer receptor exclusively activated by designer drugs" (DREADDs) technology for site-specific neural activation, a local field potential electrophysiological method for measurement of changes in the rate of neuronal activity, functional MRS for measurement of changes in NAA and a blood oxygenation level-dependent (BOLD) MR technique for evaluating changes in CBF. We show that stimulation of the rat prefrontal cortex using DREADDs results in the following: (i) an increase in level of neuronal activity; (ii) an increase in BOLD and (iii) a decrease in the NAA signal. These findings show for the first time the tightly coupled relationships between stimulation, neuron activity, CBF and NAA dynamics in brain, and also provide the first demonstration of the novel inverse stimulation-NAA phenomenon in an animal model. Copyright © 2016 John Wiley & Sons, Ltd.

  17. Resting spontaneous activity in the default mode network predicts performance decline during prolonged attention workload.

    PubMed

    Gui, Danyang; Xu, Sihua; Zhu, Senhua; Fang, Zhuo; Spaeth, Andrea M; Xin, Yuanyuan; Feng, Tingyong; Rao, Hengyi

    2015-10-15

    After continuous and prolonged cognitive workload, people typically show reduced behavioral performance and increased feelings of fatigue, which are known as "time-on-task (TOT) effects". Although TOT effects are pervasive in modern life, their underlying neural mechanisms remain elusive. In this study, we induced TOT effects by administering a 20-min continuous psychomotor vigilance test (PVT) to a group of 16 healthy adults and used resting-state blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to examine spontaneous brain activity changes associated with fatigue and performance. Behaviorally, subjects displayed robust TOT effects, as reflected by increasingly slower reaction times as the test progressed and higher self-reported mental fatigue ratings after the 20-min PVT. Compared to pre-test measurements, subjects exhibited reduced amplitudes of low-frequency fluctuation (ALFF) in the default mode network (DMN) and increased ALFF in the thalamus after the test. Subjects also exhibited reduced anti-correlations between the posterior cingulate cortex (PCC) and right middle prefrontal cortex after the test. Moreover, pre-test resting ALFF in the PCC and medial prefrontal cortex (MePFC) predicted subjects' subsequent performance decline; individuals with higher ALFF in these regions exhibited more stable reaction times throughout the 20-min PVT. These results support the important role of both task-positive and task-negative networks in mediating TOT effects and suggest that spontaneous activity measured by resting-state BOLD fMRI may be a marker of mental fatigue.

  18. Activation of the hippocampal complex during tactile maze solving in congenitally blind subjects.

    PubMed

    Gagnon, Léa; Schneider, Fabien C; Siebner, Hartwig R; Paulson, Olaf B; Kupers, Ron; Ptito, Maurice

    2012-06-01

    Despite their lack of vision, congenitally blind subjects are able to build and manipulate cognitive maps for spatial navigation. It is assumed that they thereby rely more heavily on echolocation, proprioceptive signals and environmental cues such as ambient temperature and audition to compensate for their lack of vision. Little is known, however, about the neural mechanisms underlying spatial navigation in blind individuals in settings where these cues are absent. We therefore measured behavioural performance and blood oxygenation-level dependant (BOLD) responses using functional magnetic resonance imaging (fMRI) in congenitally blind and blindfolded sighted participants while they navigated through a tactile multiple T-maze. Both groups learned the maze task at a similar pace. In blind participants, tactile maze navigation was associated with increased BOLD responses in the right hippocampus and parahippocampus, occipital cortex and fusiform gyrus. Blindfolded sighted controls did not show increased BOLD responses in these areas; instead they activated the caudate nucleus and thalamus. Both groups activated the precuneus during tactile maze navigation. We conclude that cross-modal plastic processes allow for the recruitment of the hippocampal complex and visual cortex in congenital blindness. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Emotional conflict and neuroticism: personality-dependent activation in the amygdala and subgenual anterior cingulate.

    PubMed

    Haas, Brian W; Omura, Kazufumi; Constable, R Todd; Canli, Turhan

    2007-04-01

    The amygdala and subgenual anterior cingulate (AC) have been associated with anxiety and mood disorders, for which trait neuroticism is a risk factor. Prior work has not related individual differences in amygdala or subgenual AC activation with neuroticism. Functional magnetic resonance imaging was used to investigate changes in blood oxygen level-dependent signal within the amygdala and subgenual AC associated with trait neuroticism in a nonclinical sample of 36 volunteers during an emotional conflict task. Neuroticism correlated positively with amygdala and subgenual AC activation during trials of high emotional conflict, compared with trials of low emotional conflict. The subscale of neuroticism that reflected the anxious form of neuroticism (N1) explained a greater proportion of variance within the observed clusters than the subscale of neuroticism that reflected the depressive form of neuroticism (N3). Using a task that is sensitive to individual differences in the detection of emotional conflict, the authors have provided a neural correlate of the link between neuroticism and anxiety and mood disorders. This effect was driven to a greater extent by the anxious relative to the depressive characteristics of neuroticism and may constitute vulnerability markers for anxiety-related disorders.

  20. Ciguatoxins activate specific cold pain pathways to elicit burning pain from cooling

    PubMed Central

    Vetter, Irina; Touska, Filip; Hess, Andreas; Hinsbey, Rachel; Sattler, Simon; Lampert, Angelika; Sergejeva, Marina; Sharov, Anastasia; Collins, Lindon S; Eberhardt, Mirjam; Engel, Matthias; Cabot, Peter J; Wood, John N; Vlachová, Viktorie; Reeh, Peter W; Lewis, Richard J; Zimmermann, Katharina

    2012-01-01

    Ciguatoxins are sodium channel activator toxins that cause ciguatera, the most common form of ichthyosarcotoxism, which presents with peripheral sensory disturbances, including the pathognomonic symptom of cold allodynia which is characterized by intense stabbing and burning pain in response to mild cooling. We show that intraplantar injection of P-CTX-1 elicits cold allodynia in mice by targeting specific unmyelinated and myelinated primary sensory neurons. These include both tetrodotoxin-resistant, TRPA1-expressing peptidergic C-fibres and tetrodotoxin-sensitive A-fibres. P-CTX-1 does not directly open heterologously expressed TRPA1, but when co-expressed with Nav channels, sodium channel activation by P-CTX-1 is sufficient to drive TRPA1-dependent calcium influx that is responsible for the development of cold allodynia, as evidenced by a large reduction of excitatory effect of P-CTX-1 on TRPA1-deficient nociceptive C-fibres and of ciguatoxin-induced cold allodynia in TRPA1-null mutant mice. Functional MRI studies revealed that ciguatoxin-induced cold allodynia enhanced the BOLD (Blood Oxygenation Level Dependent) signal, an effect that was blunted in TRPA1-deficient mice, confirming an important role for TRPA1 in the pathogenesis of cold allodynia. PMID:22850668

  1. Predicting conceptual processing capacity from spontaneous neuronal activity of the left middle temporal gyrus.

    PubMed

    Wei, Tao; Liang, Xia; He, Yong; Zang, Yufeng; Han, Zaizhu; Caramazza, Alfonso; Bi, Yanchao

    2012-01-11

    Conceptual processing is a crucial brain function for humans. Past research using neuropsychological and task-based functional brain-imaging paradigms indicates that widely distributed brain regions are related to conceptual processing. Here, we explore the potential contribution of intrinsic or spontaneous brain activity to conceptual processing by examining whether resting-state functional magnetic resonance imaging (rs-fMRI) signals can account for individual differences in the conceptual processing efficiencies of healthy individuals. We acquired rs-fMRI and behavioral data on object conceptual processing tasks. We found that the regional amplitude of spontaneous low-frequency fluctuations in the blood oxygen level-dependent signal in the left (posterior) middle temporal gyrus (LMTG) was highly correlated with participants' semantic processing efficiency. Furthermore, the strength of the functional connectivity between the LMTG and a series of brain regions-the left inferior frontal gyrus, bilateral anterior temporal lobe, bilateral medial temporal lobe, posterior cingulate gyrus, and ventromedial and dorsomedial prefrontal cortices-also significantly predicted conceptual behavior. The regional amplitude of low-frequency fluctuations and functionally relevant connectivity strengths of LMTG together accounted for 74% of individual variance in object conceptual performance. This semantic network, with the LMTG as its core component, largely overlaps with the regions reported in previous conceptual/semantic task-based fMRI studies. We conclude that the intrinsic or spontaneous activity of the human brain reflects the processing efficiency of the semantic system.

  2. Ciguatoxins activate specific cold pain pathways to elicit burning pain from cooling.

    PubMed

    Vetter, Irina; Touska, Filip; Hess, Andreas; Hinsbey, Rachel; Sattler, Simon; Lampert, Angelika; Sergejeva, Marina; Sharov, Anastasia; Collins, Lindon S; Eberhardt, Mirjam; Engel, Matthias; Cabot, Peter J; Wood, John N; Vlachová, Viktorie; Reeh, Peter W; Lewis, Richard J; Zimmermann, Katharina

    2012-10-03

    Ciguatoxins are sodium channel activator toxins that cause ciguatera, the most common form of ichthyosarcotoxism, which presents with peripheral sensory disturbances, including the pathognomonic symptom of cold allodynia which is characterized by intense stabbing and burning pain in response to mild cooling. We show that intraplantar injection of P-CTX-1 elicits cold allodynia in mice by targeting specific unmyelinated and myelinated primary sensory neurons. These include both tetrodotoxin-resistant, TRPA1-expressing peptidergic C-fibres and tetrodotoxin-sensitive A-fibres. P-CTX-1 does not directly open heterologously expressed TRPA1, but when co-expressed with Na(v) channels, sodium channel activation by P-CTX-1 is sufficient to drive TRPA1-dependent calcium influx that is responsible for the development of cold allodynia, as evidenced by a large reduction of excitatory effect of P-CTX-1 on TRPA1-deficient nociceptive C-fibres and of ciguatoxin-induced cold allodynia in TRPA1-null mutant mice. Functional MRI studies revealed that ciguatoxin-induced cold allodynia enhanced the BOLD (Blood Oxygenation Level Dependent) signal, an effect that was blunted in TRPA1-deficient mice, confirming an important role for TRPA1 in the pathogenesis of cold allodynia.

  3. BDNFval66met affects neural activation pattern during fear conditioning and 24 h delayed fear recall

    PubMed Central

    Golkar, Armita; Lindström, Kara M.; Haaker, Jan; Öhman, Arne; Schalling, Martin; Ingvar, Martin

    2015-01-01

    Brain-derived neurotrophic factor (BDNF), the most abundant neutrophin in the mammalian central nervous system, is critically involved in synaptic plasticity. In both rodents and humans, BDNF has been implicated in hippocampus- and amygdala-dependent learning and memory and has more recently been linked to fear extinction processes. Fifty-nine healthy participants, genotyped for the functional BDNFval66met polymorphism, underwent a fear conditioning and 24h-delayed extinction protocol while skin conductance and blood oxygenation level dependent (BOLD) responses (functional magnetic resonance imaging) were acquired. We present the first report of neural activation pattern during fear acquisition ‘and’ extinction for the BDNFval66met polymorphism using a differential conditioned stimulus (CS)+ > CS− comparison. During conditioning, we observed heightened allele dose-dependent responses in the amygdala and reduced responses in the subgenual anterior cingulate cortex in BDNFval66met met-carriers. During early extinction, 24h later, we again observed heightened responses in several regions ascribed to the fear network in met-carriers as opposed to val-carriers (insula, amygdala, hippocampus), which likely reflects fear memory recall. No differences were observed during late extinction, which likely reflects learned extinction. Our data thus support previous associations of the BDNFval66met polymorphism with neural activation in the fear and extinction network, but speak against a specific association with fear extinction processes. PMID:25103087

  4. Activated carbon from biomass

    NASA Astrophysics Data System (ADS)

    Manocha, S.; Manocha, L. M.; Joshi, Parth; Patel, Bhavesh; Dangi, Gaurav; Verma, Narendra

    2013-06-01

    Activated carbon are unique and versatile adsorbents having extended surface area, micro porous structure, universal adsorption effect, high adsorption capacity and high degree of surface reactivity. Activated carbons are synthesized from variety of materials. Most commonly used on a commercial scale are cellulosic based precursors such as peat, coal, lignite wood and coconut shell. Variation occurs in precursors in terms of structure and carbon content. Coir having very low bulk density and porous structure is found to be one of the valuable raw materials for the production of highly porous activated carbon and other important factor is its high carbon content. Exploration of good low cost and non conventional adsorbent may contribute to the sustainability of the environment and offer promising benefits for the commercial purpose in future. Carbonization of biomass was carried out in a horizontal muffle furnace. Both carbonization and activation were performed in inert nitrogen atmosphere in one step to enhance the surface area and to develop interconnecting porosity. The types of biomass as well as the activation conditions determine the properties and the yield of activated carbon. Activated carbon produced from biomass is cost effective as it is easily available as a waste biomass. Activated carbon produced by combination of chemical and physical activation has higher surface area of 2442 m2/gm compared to that produced by physical activation (1365 m2/gm).

  5. Factor XII Contact Activation.

    PubMed

    Naudin, Clément; Burillo, Elena; Blankenberg, Stefan; Butler, Lynn; Renné, Thomas

    2017-03-27

    Contact activation is the surface-induced conversion of factor XII (FXII) zymogen to the serine protease FXIIa. Blood-circulating FXII binds to negatively charged surfaces and this contact to surfaces triggers a conformational change in the zymogen inducing autoactivation. Several surfaces that have the capacity for initiating FXII contact activation have been identified, including misfolded protein aggregates, collagen, nucleic acids, and platelet and microbial polyphosphate. Activated FXII initiates the proinflammatory kallikrein-kinin system and the intrinsic coagulation pathway, leading to formation of bradykinin and thrombin, respectively. FXII contact activation is well characterized in vitro and provides the mechanistic basis for the diagnostic clotting assay, activated partial thromboplastin time. However, only in the past decade has the critical role of FXII contact activation in pathological thrombosis been appreciated. While defective FXII contact activation provides thromboprotection, excess activation underlies the swelling disorder hereditary angioedema type III. This review provides an overview of the molecular basis of FXII contact activation and FXII contact activation-associated disease states.

  6. Quantification of venous blood signal contribution to BOLD functional activation in the auditory cortex at 3 T.

    PubMed

    Casciaro, Sergio; Bianco, Roberto; Distante, Alessandro

    2008-11-01

    Most modern techniques for functional magnetic resonance imaging (fMRI) rely on blood-oxygen-level-dependent (BOLD) contrast as the basic principle for detecting neuronal activation. However, the measured BOLD effect depends on a transfer function related to neurophysiological changes accompanying electrical neural activation. The spatial accuracy and extension of the region of interest are determined by vascular effect, which introduces incertitude on real neuronal activation maps. Our efforts have been directed towards the development of a new methodology that is capable of combining morphological, vascular and functional information; obtaining new insight regarding foci of activation; and distinguishing the nature of activation on a pixel-by-pixel basis. Six healthy volunteers were studied in a parametric auditory functional experiment at 3 T; activation maps were overlaid on a high-resolution brain venography obtained through a novel technique. The BOLD signal intensities of vascular and nonvascular activated voxels were analyzed and compared: it was shown that nonvascular active voxels have lower values for signal peak (P<10(-7)) and area (P<10(-8)) with respect to vascular voxels. The analysis showed how venous blood influenced the measured BOLD signals, supplying a technique to filter possible venous artifacts that potentially can lead to misinterpretation of fMRI results. This methodology, although validated in the auditory cortex activation, maintains a general applicability to any cortical fMRI study, as the basic concepts on which it relies on are not limited to this cortical region. The results obtained in this study can represent the basis for new methodologies and tools that are capable of adding further characterization to the BOLD signal properties.

  7. Associations of neighborhood characteristics with active park use: an observational study in two cities in the USA and Belgium

    PubMed Central

    2013-01-01

    Background Public parks can be an important setting for physical activity promotion, but to increase park use and the activity levels of park users, the crucial attributes related to active park use need to be defined. Not only user characteristics and structural park attributes, but also characteristics of the surrounding neighborhood are important to examine. Furthermore, internationally comparable studies are needed, to find out if similar intervention strategies might be effective worldwide. The main aim of this study was to examine whether the overall number of park visitors and their activity levels depend on study site, neighborhood walkability and neighborhood income. Methods Data were collected in 20 parks in Ghent, Belgium and San Diego, USA. Two trained observers systematically coded park characteristics using the Environmental Assessment of Public Recreation Spaces (EAPRS) tool, and park user characteristics using the System for Observing Play and recreation in Communities (SOPARC) tool. Multilevel multiple regression models were conducted in MLwiN 2.25. Results In San Diego parks, activity levels of park visitors and number of vigorously active visitors were higher than in Ghent, while the number of visitors walking and the overall number of park visitors were lower. Neighborhood walkability was positively associated with the overall number of visitors, the number of visitors walking, number of sedentary visitors and mean activity levels of visitors. Neighborhood income was positively associated with the overall number of visitors, but negatively with the number of visitors being vigorously active. Conclusions Neighborhood characteristics are important to explain park use. Neighborhood walkability-related attributes should be taken into account when promoting the use of existing parks or creating new parks. Because no strong differences were found between parks in high- and low-income neighborhoods, it seems that promoting park use might be a promising

  8. Marine Biology Activities. Ocean Related Curriculum Activities.

    ERIC Educational Resources Information Center

    Pauls, John

    The ocean affects all of our lives. Therefore, awareness of and information about the interconnections between humans and oceans are prerequisites to making sound decisions for the future. Project ORCA (Ocean Related Curriculum Activities) has developed interdisciplinary curriculum materials designed to meet the needs of students and teachers…

  9. Mechanisms of opsin activation.

    PubMed

    Buczyłko, J; Saari, J C; Crouch, R K; Palczewski, K

    1996-08-23

    Rhodopsin is constrained in an inactive conformation by interactions with 11-cis-retinal including formation of a protonated Schiff base with Lys296. Upon photoisomerization, major structural rearrangements that involve protonation of the active site Glu113 and cytoplasmic acidic residues, including Glu134, lead to the formation of the active form of the receptor, metarhodopsin II b, which decays to opsin. However, an activated receptor may be generated without illumination by addition of all-trans-retinal or its analogues to opsin, as measured in this study by the increased phosphorylation of opsin by rhodopsin kinase. The potency of stimulation depended on the chemical and isomeric nature of the analogues and the length of the polyene chain with all-trans-C17 aldehyde and all-trans-retinal being the most active and trans-C12 aldehyde being the least active. Certain cis-isomers, 11-cis-13-demethyl-retinal and 9-cis-C17 aldehyde, were also active. Most of the retinal analogues tested did not regenerate a spectrally identifiable pigment, and many were incapable of Schiff base formation (ketone, stable oximes, and Schiff base-derivatives of retinal). Thus, receptor activation resulted from formation of non-covalent complexes with opsin. pH titrations suggested that an equilibrium exists between partially active (protonated) and inactive (deprotonated) forms of opsin. These findings are consistent with a model in which protonation of one or more cytoplasmic carboxyl groups of opsin is essential for activity. Upon addition of retinoids, the partially active conformation of opsin is converted to a more active intermediate similar to metarhodopsin II b. The model provides an understanding of the structural requirements for opsin activation and an interpretation of the observed activities of natural and experimental opsin mutants.

  10. Central neural activation following contact sensitivity peripheral immune challenge: evidence of brain-immune regulation through C fibres.

    PubMed

    Thinschmidt, Jeffrey S; King, Michael A; Korah, Maria; Perez, Pablo D; Febo, Marcelo; Miyan, Jaleel; Grant, Maria B

    2015-10-01

    This study tested the hypothesis that peripheral immune challenges will produce predictable activation patterns in the rat brain consistent with sympathetic excitation. As part of examining this hypothesis, this study asked whether central activation is dependent on capsaicin-sensitive C-fibres. We induced skin contact sensitivity immune responses with 2,4-dinitrochlorobenzene (DNCB), in the presence or absence of the acute C-fibre toxin capsaicin (8-methyl-N-vanillyl-6-nonenamide) to trigger immune responses with and without diminished activity of C-fibres. Innovative blood-oxygen-level-dependent functional magnetic resonance imaging data revealed that the skin contact sensitivity immune responses induced with DNCB were associated with localized increases in brain neuronal activity in treated rats. This response was diminished by pre-treatment with capsaicin 1 week before scans. In the same animals, we found expression of the immediate early gene c-Fos in sub-regions of the amygdala and hypothalamic sympathetic brain nuclei. Significant increases in c-Fos expression were found in the supraoptic nucleus, central amygdala and medial habenula following immune challenges. Our results support the idea that selective brain regions, some of which are associated with sympathetic function, process or modulate immune function through pathways that are partially dependent on C-fibres. Together with previous studies demonstrating the motor control pathways from brain to immune targets, these findings indicate a central neuroimmune system to monitor host status and coordinate appropriate host responses.

  11. How and when the fMRI BOLD signal relates to underlying neural activity: The danger in dissociation

    PubMed Central

    Ekstrom, Arne

    2013-01-01

    Functional magnetic resonance imaging (fMRI) has become the dominant means of measuring behavior-related neural activity in the human brain. Yet the relation between the blood oxygen-level dependent (BOLD) signal and underlying neural activity remains an open and actively researched question. A widely accepted model, established for sensory neo-cortex, suggests that the BOLD signal reflects peri-synaptic activity in the form of the local field potential rather than the spiking rate of individual neurons. Several recent experimental results, however, suggest situations in which BOLD, spiking, and the local field potential dissociate. Two different models are discussed, based on the literature reviewed to account for this dissociation, a circuitry-based and vascular-based explanation. Both models are found to account for existing data under some testing situations and in certain brain regions. Because both the vascular and local circuitry-based explanations challenge the BOLD-LFP coupling model, these models provide guidance in predicting when BOLD can be expected to reflect neural processing and when the underlying relation with BOLD may be more complex than a direct correspondence. PMID:20026191

  12. Central neural activation following contact sensitivity peripheral immune challenge: evidence of brain–immune regulation through C fibres

    PubMed Central

    Thinschmidt, Jeffrey S; King, Michael A; Korah, Maria; Perez, Pablo D; Febo, Marcelo; Miyan, Jaleel; Grant, Maria B

    2015-01-01

    This study tested the hypothesis that peripheral immune challenges will produce predictable activation patterns in the rat brain consistent with sympathetic excitation. As part of examining this hypothesis, this study asked whether central activation is dependent on capsaicin-sensitive C-fibres. We induced skin contact sensitivity immune responses with 2,4-dinitrochlorobenzene (DNCB), in the presence or absence of the acute C-fibre toxin capsaicin (8-methyl-N-vanillyl-6-nonenamide) to trigger immune responses with and without diminished activity of C-fibres. Innovative blood-oxygen-level-dependent functional magnetic resonance imaging data revealed that the skin contact sensitivity immune responses induced with DNCB were associated with localized increases in brain neuronal activity in treated rats. This response was diminished by pre-treatment with capsaicin 1 week before scans. In the same animals, we found expression of the immediate early gene c-Fos in sub-regions of the amygdala and hypothalamic sympathetic brain nuclei. Significant increases in c-Fos expression were found in the supraoptic nucleus, central amygdala and medial habenula following immune challenges. Our results support the idea that selective brain regions, some of which are associated with sympathetic function, process or modulate immune function through pathways that are partially dependent on C-fibres. Together with previous studies demonstrating the motor control pathways from brain to immune targets, these findings indicate a central neuroimmune system to monitor host status and coordinate appropriate host responses. PMID:25967648

  13. Top-down Modulation of Neural Activity in Anticipatory Visual Attention: Control Mechanisms Revealed by Simultaneous EEG-fMRI.

    PubMed

    Liu, Yuelu; Bengson, Jesse; Huang, Haiqing; Mangun, George R; Ding, Mingzhou

    2016-02-01

    In covert visual attention, frontoparietal attention control areas are thought to issue signals to selectively bias sensory neurons to facilitate behaviorally relevant information and suppress distraction. We investigated the relationship between activity in attention control areas and attention-related modulation of posterior alpha activity using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging in humans during cued visual-spatial attention. Correlating single-trial EEG alpha power with blood-oxygen-level dependent (BOLD) activity, we found that BOLD in the intraparietal sulcus (IPS) and left middle frontal gyrus was inversely correlated with occipital alpha power. Importantly, in IPS, inverse correlations were stronger for alpha within the hemisphere contralateral to the attended hemifield, implicating the IPS in the enhancement of task-relevant sensory areas. Positive BOLD-alpha correlations were observed in sensorimotor cortices and the default mode network, suggesting a mechanism of active suppression over task-irrelevant areas. The magnitude of cue-induced alpha lateralization was positively correlated with BOLD in dorsal anterior cingulate cortex and dorsolateral prefrontal cortex, implicating a role of executive control in attention. These results show that IPS and frontal executive areas are the main sources of biasing influences on task-relevant visual cortex, whereas task-irrelevant default mode network and sensorimotor cortex are inhibited during visual attention.

  14. Implications of cortical balanced excitation and inhibition, functional heterogeneity, and sparseness of neuronal activity in fMRI

    PubMed Central

    Xu, Jiansong

    2015-01-01

    Blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) studies often report inconsistent findings, probably due to brain properties such as balanced excitation and inhibition and functional heterogeneity. These properties indicate that different neurons in the same voxels may show variable activities including concurrent activation and deactivation, that the relationships between BOLD signal and neural activity (i.e., neurovascular coupling) are complex, and that increased BOLD signal may reflect reduced deactivation, increased activation, or both. The traditional general-linear-model-based-analysis (GLM-BA) is a univariate approach, cannot separate different components of BOLD signal mixtures from the same voxels, and may contribute to inconsistent findings of fMRI. Spatial independent component analysis (sICA) is a multivariate approach, can separate the BOLD signal mixture from each voxel into different source signals and measure each separately, and thus may reconcile previous conflicting findings generated by GLM-BA. We propose that methods capable of separating mixed signals such as sICA should be regularly used for more accurately and completely extracting information embedded in fMRI datasets. PMID:26341939

  15. Mechanics of active surfaces

    NASA Astrophysics Data System (ADS)

    Salbreux, Guillaume; Jülicher, Frank

    2017-09-01

    We derive a fully covariant theory of the mechanics of active surfaces. This theory provides a framework for the study of active biological or chemical processes at surfaces, such as the cell cortex, the mechanics of epithelial tissues, or reconstituted active systems on surfaces. We introduce forces and torques acting on a surface, and derive the associated force balance conditions. We show that surfaces with in-plane rotational symmetry can have broken up-down, chiral, or planar-chiral symmetry. We discuss the rate of entropy production in the surface and write linear constitutive relations that satisfy the Onsager relations. We show that the bending modulus, the spontaneous curvature, and the surface tension of a passive surface are renormalized by active terms. Finally, we identify active terms which are not found in a passive theory and discuss examples of shape instabilities that are related to active processes in the surface.

  16. Patterns in Active Nematics

    NASA Astrophysics Data System (ADS)

    Yeomans, Julia M.

    Active systems, from bacterial suspensions to cellular monolayers, are continuously driven out of equilibrium by local injection of energy from their constituent elements and exhibit turbulent-like, chaotic patterns. We describe how active systems can be stabilised by tuning a physical feature of the system, friction. We demonstrate how the crossover between wet active systems, whose behaviour is dominated by hydrodynamics, and dry active matter where any flow is screened, can be achieved by using friction as a control parameter and demonstrate vortex ordering at the wet-dry crossover. We show that the self organisation of vortices into lattices is accompanied by the spatial ordering of topological defects leading to active crystal-like structures. The emergence of vortex lattices which leads to the positional ordering of topological defects may be a useful step towards the design and control of active materials.

  17. [Biomedical activity of biosurfactants].

    PubMed

    Krasowska, Anna

    2010-07-23

    Biosurfactants, amphiphilic compounds, synthesized by microorganisms have surface, antimicrobial and antitumor properties. Biosurfactants prevent adhesion and biofilms formation by bacteria and fungi on various surfaces. For many years microbial surfactants are used as antibiotics with board spectrum of activity against microorganisms. Biosurfactants act as antiviral compounds and their antitumor activities are mediated through induction of apoptosis. This work presents the current state of knowledge related to biomedical activity of biosurfactants.

  18. Gyrating Active Region

    NASA Image and Video Library

    2017-01-26

    On Jan. 20, 2017, NASA Solar Dynamics Observatory captured a small area of the sun highlighted three active region. Over half a day this active region sent dark swirls of plasma and bright magnetic arches twisting and turning above it. All the activity in the three areas was driven by competing magnetic forces. The dynamic action was observed in a wavelength of extreme ultraviolet light. Movies are available at http://photojournal.jpl.nasa.gov/catalog/PIA11703

  19. Active Regions Blossoming

    NASA Image and Video Library

    2015-10-28

    As a pair of active regions began to rotate into view, their towering magnetic field lines above them bloomed into a dazzling display of twisting arches (Oct. 27-28, 2015). Some of the lines reached over and connected with the neighboring active region. Active regions are usually the source of solar storms. The images were taken in a wavelength of extreme ultraviolet light. http://photojournal.jpl.nasa.gov/catalog/PIA20048

  20. Activity in distant comets

    NASA Technical Reports Server (NTRS)

    Luu, Jane X.

    1992-01-01

    Activity in distant comets remains a mystery in the sense that we still have no complete theory to explain the various types of activity exhibited by different comets at large distances. This paper explores the factors that should play a role in determining activity in a distant comet, especially in the cases of comet P/Tempel 2, comet Schwassmann-Wachmann 1, and 2060 Chiron.

  1. Activated recombinant adenovirus proteinases

    DOEpatents

    Anderson, C.W.; Mangel, W.F.

    1999-08-10

    This application describes methods and expression constructs for producing activatable recombinant adenovirus proteinases. Purified activatable recombinant adenovirus proteinases and methods of purification are described. Activated adenovirus proteinases and methods for obtaining activated adenovirus proteinases are further included. Isolated peptide cofactors of adenovirus proteinase activity, methods of purifying and identifying peptide cofactors are also described. Antibodies immunoreactive with adenovirus proteinases, immunospecific antibodies, and methods for preparing them are also described. Other related methods and materials are also described. 29 figs.

  2. Activated recombinant adenovirus proteinases

    DOEpatents

    Anderson, Carl W.; Mangel, Walter F.

    1999-08-10

    This application describes methods and expression constructs for producing activatable recombinant adenovirus proteinases. Purified activatable recombinant adenovirus proteinases and methods of purification are described. Activated adenovirus proteinases and methods for obtaining activated adenovirus proteinases are further included. Isolated peptide cofactors of adenovirus proteinase activity, methods of purifying and identifying said peptide cofactors are also described. Antibodies immunoreactive with adenovirus proteinases, immunospecific antibodies, and methods for preparing them are also described. Other related methods and materials are also described.

  3. Thermally Activated Driver

    NASA Technical Reports Server (NTRS)

    Kinard, William H.; Murray, Robert C.; Walsh, Robert F.

    1987-01-01

    Space-qualified, precise, large-force, thermally activated driver (TAD) developed for use in space on astro-physics experiment to measure abundance of rare actinide-group elements in cosmic rays. Actinide cosmic rays detected using thermally activated driver as heart of event-thermometer (ET) system. Thermal expansion and contraction of silicone oil activates driver. Potential applications in fluid-control systems where precise valve controls are needed.

  4. Solar Activity and TECHNOSPHERE

    NASA Astrophysics Data System (ADS)

    Kuznetsov, V. D.

    2017-05-01

    A review of solar activity factors impacting on the near-Earth space and technosphere are given. Solar activity in the form of enhanced fluxes of hard electromagnetic and corpuscular radiation, solar wind streams and mass ejections is considered as a principal source of space weather creating the dangerous for the astronauts, satellites, International Space Station and for the ground technical systems. The examples of effects of solar activity on the space and ground technosphere are given.

  5. Fast fMRI can detect oscillatory neural activity in humans

    PubMed Central

    Lewis, Laura D.; Setsompop, Kawin; Rosen, Bruce R.; Polimeni, Jonathan R.

    2016-01-01

    Oscillatory neural dynamics play an important role in the coordination of large-scale brain networks. High-level cognitive processes depend on dynamics evolving over hundreds of milliseconds, so measuring neural activity in this frequency range is important for cognitive neuroscience. However, current noninvasive neuroimaging methods are not able to precisely localize oscillatory neural activity above 0.2 Hz. Electroencephalography and magnetoencephalography have limited spatial resolution, whereas fMRI has limited temporal resolution because it measures vascular responses rather than directly recording neural activity. We hypothesized that the recent development of fast fMRI techniques, combined with the extra sensitivity afforded by ultra-high-field systems, could enable precise localization of neural oscillations. We tested whether fMRI can detect neural oscillations using human visual cortex as a model system. We detected small oscillatory fMRI signals in response to stimuli oscillating at up to 0.75 Hz within single scan sessions, and these responses were an order of magnitude larger than predicted by canonical linear models. Simultaneous EEG–fMRI and simulations based on a biophysical model of the hemodynamic response to neuronal activity suggested that the blood oxygen level-dependent response becomes faster for rapidly varying stimuli, enabling the detection of higher frequencies than expected. Accounting for phase delays across voxels further improved detection, demonstrating that identifying vascular delays will be of increasing importance with higher-frequency activity. These results challenge the assumption that the hemodynamic response is slow, and demonstrate that fMRI has the potential to map neural oscillations directly throughout the brain. PMID:27729529

  6. Differences in Neural Activity when Processing Emotional Arousal and Valence in Autism Spectrum Disorders

    PubMed Central

    Tseng, Angela; Wang, Zhishun; Huo, Yuankai; Goh, Suzanne; Russell, James A.; Peterson, Bradley S.

    2016-01-01

    Individuals with autism spectrum disorders (ASD) often have difficulty recognizing and interpreting facial expressions of emotion, which may impair their ability to navigate and communicate successfully in their social, interpersonal environments. Characterizing specific differences between individuals with ASD and their typically-developing (TD) counterparts in the neural activity subserving their experience of emotional faces may provide distinct targets for ASD interventions. Thus we used functional magnetic resonance imaging (fMRI) and a parametric experimental design to identify brain regions in which neural activity correlated with ratings of arousal and valence for a broad range of emotional faces. Participants (51 ASD, 84 TD) were group-matched by age, sex, IQ, race, and socioeconomic status. Using task-related change in blood-oxygen-level-dependent (BOLD) fMRI signal as a measure, and covarying for age, sex, FSIQ, and ADOS scores, we detected significant differences across diagnostic groups in the neural activity subserving the dimension of arousal but not valence. BOLD-signal in TD participants correlated inversely with ratings of arousal in regions associated primarily with attentional functions, whereas BOLD-signal in ASD participants correlated positively with arousal ratings in regions commonly associated with impulse control and default-mode activity. Only minor differences were detected between groups in the BOLD signal correlates of valence ratings. Our findings provide unique insight into the emotional experiences of individuals with ASD. Although behavioral responses to face-stimuli were comparable across diagnostic groups, the corresponding neural activity for our ASD and TD groups differed dramatically. The near absence of group differences for valence correlates and the presence of strong group differences for arousal correlates suggest that individuals with ASD are not atypical in all aspects of emotion-processing. Studying these similarities

  7. NASA metrication activities

    NASA Technical Reports Server (NTRS)

    Vlannes, P. N.

    1978-01-01

    NASA's organization and policy for metrification, history from 1964, NASA participation in Federal agency activities, interaction with nongovernmental metrication organizations, and the proposed metrication assessment study are reviewed.

  8. Mast cell activation disorders.

    PubMed

    Akin, Cem

    2014-01-01

    Disorders associated with mast cell activation range from relatively common IgE-mediated disease and chronic urticaria to rarer conditions such as mastocytosis or monoclonal mast cell activation disorder. Mast cell activation disorders can be mechanistically classified into primary (associated with abnormal production of mast cells that carry pathologic markers of clonality), secondary (normal mast cells activated in reaction to a microenvironmental trigger), and idiopathic (no etiology is found). Clinical presentations, diagnostic criteria as well as general principles of a stepwise therapy approach are discussed.

  9. Deriving blood-oxygen-level-dependent contrast in MRI with T2*-weighted, T2-prepared and phase-cycled SSFP methods: theory and experiment.

    PubMed

    Arumana, Jain Mangalathu; Li, Debiao; Dharmakumar, Rohan

    2008-03-01

    The objectives of this work were: 1) to perform a comparative evaluation of the oxygen-sensitive contrast (OC) derived from the phase-cycled steady-state free precession (SSFP PC) method against T*2-weighted gradient recalled echo (GRE) and T2-prepared (T2-prep) methods with theoretical simulations and imaging studies using an ischemic leg cuff model at 1.5T and 3.0T; and 2) to investigate the dependence of SSFP PC-based OC on imaging parameters. Results showed that the SSFP PC method (repetition time (TR) = 6.3 ms; flip angle (alpha) = 90 degrees ) provides significantly higher OC compared to T2-prep (at both field strengths) and GRE (3.0T) (P < 0.05). The OC of low TR SSFP (TR = 3.5 ms at 1.5T; TR = 4.5 ms at 3.0T; alpha = 90 degrees ) was significantly lower compared to GRE (P < 0.05) at 1.5T and 3.0T and to T2-prep methods at 1.5T (P < 0.05). In summary, the findings from this study are the following: 1) SSFP-based OC is directly dependent on TR and alpha at 1.5T and 3.0T; and 2) OC derived with SSFP PC can be increased above GRE and T2-prep methods with an appropriate choice of imaging parameters. (c) 2008 Wiley-Liss, Inc.

  10. Multiparametric assessment of vascular function in peripheral artery disease: dynamic measurement of skeletal muscle perfusion, blood-oxygen-level dependent signal, and venous oxygen saturation.

    PubMed

    Englund, Erin K; Langham, Michael C; Ratcliffe, Sarah J; Fanning, Molly J; Wehrli, Felix W; Mohler, Emile R; Floyd, Thomas F

    2015-04-01

    Endothelial dysfunction present in patients with peripheral artery disease may be better understood by measuring the temporal dynamics of blood flow and oxygen saturation during reactive hyperemia than by conventional static measurements. Perfusion, Intravascular Venous Oxygen saturation, and T2* (PIVOT), a recently developed MRI technique, was used to measure the response to an ischemia-reperfusion paradigm in 96 patients with peripheral artery disease of varying severity and 10 healthy controls. Perfusion, venous oxygen saturation SvO2, and T2* were each quantified in the calf at 2-s temporal resolution, yielding a dynamic time course for each variable. Compared with healthy controls, patients had a blunted and delayed hyperemic response. Moreover, patients with lower ankle-brachial index had (1) a more delayed reactive hyperemia response time, manifesting as an increase in time to peak perfusion in the gastrocnemius, soleus, and peroneus muscles, and in the anterior compartment, (2) an increase in the time to peak T2* measured in the soleus muscle, and (3) a prolongation of the posterior tibial vein SvO2 washout time. Intrasession and intersession repeatability were also assessed. Results indicated that time to peak perfusion and time to peak T2* were the most reliable extracted time course metrics. Perfusion, dynamic SvO2, and T2* response times after induced ischemia are highly correlated with peripheral artery disease severity. Combined imaging of peripheral microvascular blood flow and dynamics of oxygen saturation with Perfusion, intravascular SvO2, and T2* may be a useful tool to investigate the pathophysiology of peripheral artery disease. © 2015 American Heart Association, Inc.

  11. Regional placental blood oxygen level dependent (BOLD) changes with gestational age in normally developing pregnancies using long duration R2* mapping in utero

    NASA Astrophysics Data System (ADS)

    Dighe, Manjiri; Kim, Yun Jung; Seshamani, Sharmishtaa; Blazejewska, Ania I.; Mckown, Susan; Caucutt, Jason; Gatenby, Christopher; Studholme, Colin

    2016-03-01

    The aim of this study was to examine the use of R2* mapping in maternal and fetal sub-regions of the placenta with the aim of providing a reference for blood oxygenation levels during normative development. There have been a number of MR relaxation studies of placental tissues in-utero, but none have reported R2* value changes with age, or examined differences in sub-regions of the placenta. Here specialized long-duration Multi-frame R2* imaging was used to create a stable estimate for R2* values in different placental regions in healthy pregnant volunteers not imaged for clinical reasons. 27 subjects were recruited and scanned up to 3 times during their pregnancy. A multi-slice dual echo EPI based BOLD acquisition was employed and repeated between 90 and 150 times over 3 to 5 minutes to provide a high accuracy estimate of the R2* signal level. Acquisitions were also repeated in 13 cases within a visit to evaluate reproducibility of the method in a given subject. Experimental results showed R2* measurements were highly repeatable within a visit with standard deviation of (0.76). Plots of all visits against gestational age indicated clear correlations showing decreases in R2* with age. This increase was consistent was also consistent over time in multiple visits of the same volunteer during their pregnancy. Maternal and fetal regional changes with gestational age followed the same trend with increase in R2* over the gestational age.

  12. The effect of ABCG5/G8 polymorphisms on plasma HDL cholesterol levels depends on the ABCA1 gene variation in the Boston Puerto Rican Health Study

    USDA-ARS?s Scientific Manuscript database

    Background: ATP-binding cassette transporters G5/G8 have shown an association with HDL-C. One of the most likely mechanisms to explain those associations is through ABCA1. Objective: To assess whether the effect of ABCG5/G8 polymorphisms on HDL-C is dependent on ABCA1, we studied potential interacti...

  13. Early host responses to avian influenza A virus are prolonged and enhanced at transcriptional level depending on maturation of the immune system.

    PubMed

    Reemers, Sylvia S; van Leenen, Dik; Koerkamp, Marian J Groot; van Haarlem, Daphne; van de Haar, Peter; van Eden, Willem; Vervelde, Lonneke

    2010-05-01

    Newly hatched chickens are more susceptible to infectious diseases than older birds because of an immature immune system. The aim of this study was to determine to what extent host responses to avian influenza virus (AIV) inoculation are affected by age. Therefore, 1- and 4-week (wk) old birds were inoculated with H9N2 AIV or saline. The trachea and lung were sampled at 0, 8, 16 and 24h post-inoculation (h.p.i.) and gene expression profiles determined using microarray analysis. Firstly, saline controls of both groups were compared to analyse the changes in gene profiles related to development. In 1-wk-old birds, higher expression of genes related to development of the respiratory immune system and innate responses were found, whereas in 4-wk-old birds genes were up regulated that relate to the presence of higher numbers of leukocytes in the respiratory tract. After inoculation with H9N2, gene expression was most affected at 16 h.p.i. in 1-wk-old birds and at 16 and 24h.p.i. in 4-wk-old birds in the trachea and especially in the lung. In 1-wk-old birds less immune related genes including innate related genes were induced which might be due to age-dependent reduced functionality of antigen presenting cells (APC), T cells and NK cells. In contrast cytokine and chemokines gene expression was related to viral load in 1-wk-old birds and less in 4-wk-old birds. Expression of cellular host factors that block virus replication by interacting with viral factors was independent of age or tissue for most host factors. These data show that differences in development are reflected in gene expression and suggest that the strength of host responses at transcriptional level may be a key factor in age-dependent susceptibility to infection, and the cellular host factors involved in virus replication are not.

  14. Active Flow Control Activities at NASA Langley

    NASA Technical Reports Server (NTRS)

    Anders, Scott G.; Sellers, William L., III; Washburn, Anthony E.

    2004-01-01

    NASA Langley continues to aggressively investigate the potential advantages of active flow control over more traditional aerodynamic techniques. This paper provides an update to a previous paper and describes both the progress in the various research areas and the significant changes in the NASA research programs. The goals of the topics presented are focused on advancing the state of knowledge and understanding of controllable fundamental mechanisms in fluids as well as to address engineering challenges. An organizational view of current research activities at NASA Langley in active flow control as supported by several projects is presented. On-center research as well as NASA Langley funded contracts and grants are discussed at a relatively high level. The products of this research are to be demonstrated either in bench-top experiments, wind-tunnel investigations, or in flight as part of the fundamental NASA R&D program and then transferred to more applied research programs within NASA, DOD, and U.S. industry.

  15. Role of Ongoing, Intrinsic Activity of Neuronal Populations for Quantitative Neuroimaging of Functional Magnetic Resonance Imaging–Based Networks

    PubMed Central

    Herman, Peter; Sanganahalli, Basavaraju G.; Coman, Daniel; Blumenfeld, Hal; Rothman, Douglas L.

    2011-01-01

    Abstract A primary objective in neuroscience is to determine how neuronal populations process information within networks. In humans and animal models, functional magnetic resonance imaging (fMRI) is gaining increasing popularity for network mapping. Although neuroimaging with fMRI—conducted with or without tasks—is actively discovering new brain networks, current fMRI data analysis schemes disregard the importance of the total neuronal activity in a region. In task fMRI experiments, the baseline is differenced away to disclose areas of small evoked changes in the blood oxygenation level-dependent (BOLD) signal. In resting-state fMRI experiments, the spotlight is on regions revealed by correlations of tiny fluctuations in the baseline (or spontaneous) BOLD signal. Interpretation of fMRI-based networks is obscured further, because the BOLD signal indirectly reflects neuronal activity, and difference/correlation maps are thresholded. Since the small changes of BOLD signal typically observed in cognitive fMRI experiments represent a minimal fraction of the total energy/activity in a given area, the relevance of fMRI-based networks is uncertain, because the majority of neuronal energy/activity is ignored. Thus, another alternative for quantitative neuroimaging of fMRI-based networks is a perspective in which the activity of a neuronal population is accounted for by the demanded oxidative energy (CMRO2). In this article, we argue that network mapping can be improved by including neuronal energy/activity of both the information about baseline and small differences/fluctuations of BOLD signal. Thus, total energy/activity information can be obtained through use of calibrated fMRI to quantify differences of ΔCMRO2 and through resting-state positron emission tomography/magnetic resonance spectroscopy measurements for average CMRO2. PMID:22433047

  16. Regional Homogeneity of Resting-state fMRI Contributes to Both Neurovascular and Task Activation Variations

    PubMed Central

    Yuan, Rui; Di, Xin; Kim, Eun H.; Barik, Sabrina; Rypma, Bart; Biswal, Bharat B.

    2013-01-01

    The task induced blood oxygenation level dependent signal changes observed using functional magnetic resonance imaging (fMRI) is critically dependent on the relationship between neuronal activity and hemodynamic response. Therefore, understanding the nature of neurovascular coupling is important when interpreting fMRI signal changes evoked via task. In this study, we used regional homogeneity (ReHo), a measure of local synchronization of the BOLD time series, to investigate whether the similarities of one voxel with the surrounding voxels is a property of neurovascular coupling. FMRI scans were obtained from fourteen subjects during bilateral finger tapping (FTAP), digit-symbol substitution (DSST) and periodic breath holding (BH) paradigm. A resting-state scan was also obtained for each of the subjects for 4 minutes using identical imaging parameters. Inter-voxel correlation analyses were conducted between the resting-state ReHo, resting-state amplitude of low frequency fluctuations (ALFF), breath hold (BH) responses and task activations within the masks related to task activations. There was a reliable mean voxel-wise spatial correlation between ReHo and other neurovascular variables (BH responses and ALFF). We observed a moderate correlation between ReHo and task activations (FTAP: r = 0.32; DSST: r = 0.22) within the task positive network and a small yet reliable correlation within the default mode network (DSST: r = −0.08). Subsequently, a linear regression was used to estimate the contribution of ReHo, ALFF and BH responses to the task activated voxels. The unique contribution of ReHo was minimal. The results suggest that regional synchrony of the BOLD activity is a property that can explain the variance of neurovascular coupling and task activations; but its contribution to task activations can be accounted for by other neurovascular factors such as the ALFF. PMID:23969197

  17. Regional homogeneity of resting-state fMRI contributes to both neurovascular and task activation variations.

    PubMed

    Yuan, Rui; Di, Xin; Kim, Eun H; Barik, Sabrina; Rypma, Bart; Biswal, Bharat B

    2013-11-01

    The task induced blood oxygenation level dependent signal changes observed using functional magnetic resonance imaging (fMRI) are critically dependent on the relationship between neuronal activity and hemodynamic response. Therefore, understanding the nature of neurovascular coupling is important when interpreting fMRI signal changes evoked via task. In this study, we used regional homogeneity (ReHo), a measure of local synchronization of the BOLD time series, to investigate whether the similarities of one voxel with the surrounding voxels are a property of neurovascular coupling. FMRI scans were obtained from fourteen subjects during bilateral finger tapping (FTAP), digit-symbol substitution (DSST) and periodic breath holding (BH) paradigm. A resting-state scan was also obtained for each of the subjects for 4min using identical imaging parameters. Inter-voxel correlation analyses were conducted between the resting-state ReHo, resting-state amplitude of low frequency fluctuations (ALFF), BH responses and task activations within the masks related to task activations. There was a reliable mean voxel-wise spatial correlation between ReHo and other neurovascular variables (BH responses and ALFF). We observed a moderate correlation between ReHo and task activations (FTAP: r=0.32; DSST: r=0.22) within the task positive network and a small yet reliable correlation within the default mode network (DSST: r=-0.08). Subsequently, a linear regression was used to estimate the contribution of ReHo, ALFF and BH responses to the task activated voxels. The unique contribution of ReHo was minimal. The results suggest that regional synchrony of the BOLD activity is a property that can explain the variance of neurovascular coupling and task activations; but its contribution to task activations can be accounted for by other neurovascular factors such as the ALFF. © 2013.

  18. Treatment effects on insular and anterior cingulate cortex activation during classic and emotional Stroop interference in child abuse-related complex post-traumatic stress disorder.

    PubMed

    Thomaes, K; Dorrepaal, E; Draijer, N; de Ruiter, M B; Elzinga, B M; van Balkom, A J; Smit, J H; Veltman, D J

    2012-11-01

    Functional neuroimaging studies have shown increased Stroop interference coupled with altered anterior cingulate cortex (ACC) and insula activation in post-traumatic stress disorder (PTSD). These brain areas are associated with error detection and emotional arousal. There is some evidence that treatment can normalize these activation patterns. At baseline, we compared classic and emotional Stroop performance and blood oxygenation level-dependent responses (functional magnetic resonance imaging) of 29 child abuse-related complex PTSD patients with 22 non-trauma-exposed healthy controls. In 16 of these patients, we studied treatment effects of psycho-educational and cognitive behavioural stabilizing group treatment (experimental treatment; EXP) added to treatment as usual (TAU) versus TAU only, and correlations with clinical improvement. At baseline, complex PTSD patients showed a trend for increased left anterior insula and dorsal ACC activation in the classic Stroop task. Only EXP patients showed decreased dorsal ACC and left anterior insula activation after treatment. In the emotional Stroop contrasts, clinical improvement was associated with decreased dorsal ACC activation and decreased left anterior insula activation. We found further evidence that successful treatment in child abuse-related complex PTSD is associated with functional changes in the ACC and insula, which may be due to improved selective attention and lower emotional arousal, indicating greater cognitive control over PTSD symptoms.

  19. Activities: More Calculator Capers.

    ERIC Educational Resources Information Center

    Schmalz, Rosemary

    1983-01-01

    Provided is an activity designed to give grades 7-12 students opportunities to discover numerical patterns and to derive general conclusions from observing data. The activity focuses attention on patterns in products such as 33x34, 333x334, and 3333x3334. Three worksheets and answers are included. (JN)

  20. Activity Book: Ocean Ecology.

    ERIC Educational Resources Information Center

    Learning, 1992

    1992-01-01

    Presents a collection of activities to help elementary students study ocean ecology. The activities have students investigate ocean inhabitants, analyze animal adaptations, examine how temperature and saltiness affect ocean creatures, and learn about safeguarding the sea. Student pages offer reproducible learning sheets. (SM)

  1. [Biosignals of dermal activity].

    PubMed

    Rathkolb, O; Gallei, L

    1993-01-01

    Electrodermal activity (EDA) summarizes different electrophysiological dimensions of human skin. EDA is based on the activity of sweat glands and their innervation by the autonomic nervous system. EDA is used as indicator in the additional diagnostic assessment of patients in the fields of neurology and psychosomatic medicine.

  2. Active galactic nuclei

    PubMed Central

    Fabian, Andrew C.

    1999-01-01

    Active galactic nuclei are the most powerful, long-lived objects in the Universe. Recent data confirm the theoretical idea that the power source is accretion into a massive black hole. The common occurrence of obscuration and outflows probably means that the contribution of active galactic nuclei to the power density of the Universe has been generally underestimated. PMID:10220363

  3. Outside Professional Activities.

    ERIC Educational Resources Information Center

    Dillon, Kristine

    The disadvantages of faculty participation in outside professional activities that result in extra income are discussed. These activities include: consulting, producing copyrighted and patented works, giving speeches or lectures, and teaching for other institutions and organizations. A significant increase in the amount of outside consulting work…

  4. Peak Longevity Physical Activity

    Cancer.gov

    People who engage in three to five times the recommended minimum level of leisure-time physical activity derive the greatest benefit in terms of mortality reduction when compared with people who do not engage in leisure-time physical activity.

  5. The Activity of Trypsin

    ERIC Educational Resources Information Center

    Russo, Salvatore F.; Holzman, Tom

    1977-01-01

    Describes an experiment that illustrates the following points concerning the experimental determination of trypsin activity: (1) there is a difference in basing enzyme concentration on weight, absorbance, or active sites; and (2) the method of expressing enzyme concentration determines the value of specific, molecular, and catalytic center…

  6. Science World Activities Book.

    ERIC Educational Resources Information Center

    Wisconsin Academy of Sciences, Arts and Letters, Madison.

    This document consists of three sections. Section I contains 19 activities developed by master teachers for the Science World '84 summer science program. These activities focus on studies involving airplane controls, trash bag kites, computers, meteorology, compass orienteering, soils, aquatic ecosystems, bogs, and others. Objectives, materials…

  7. Activation of fly ash

    DOEpatents

    Corbin, D.R.; Velenyi, L.J.; Pepera, M.A.; Dolhyj, S.R.

    1986-08-19

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  8. Curriculum Activities on Aging.

    ERIC Educational Resources Information Center

    Schmall, Vicki L.; Benge, Nancy

    This paper contains learning activities on aging for use with elementary, high school, and university students in health, family relationships, social studies, and art courses. The activities are intended to help youth develop a more realistic understanding of the aging process and to become aware of both the problems and benefits associated with…

  9. Nature's engines: active matter

    NASA Astrophysics Data System (ADS)

    Yeomans, Julia M.

    2017-03-01

    Active materials, bacteria, molecular motors, and self-propelled colloids, continuously transform chemical energy from the environment to mechanical work. Dense active matter, from layers of cells to flocks of birds, self-assembles into intricate patterns. Nature's engines are complex and efficient, and we would like to exploit her ideas to fabricate nano-machines.

  10. Bonus Activity Book.

    ERIC Educational Resources Information Center

    Learning, 1992

    1992-01-01

    A collection of activities and tips for elementary teachers, culled from material the magazine has published over 20 years, includes cornerstones of classroom management, top teaching strategies, and curriculum classics. A new poster offers activities for commemorating student birthdays and for enjoying the first day of school. (SM)

  11. Reflections on Activity Theory

    ERIC Educational Resources Information Center

    Bakhurst, David

    2009-01-01

    It is sometimes suggested that activity theory represents the most important legacy of Soviet philosophy and psychology. But what exactly "is" activity theory? The canonical account in the West is given by Engestrom, who identifies three stages in the theory's development: from Vygotsky's insights, through Leontiev's articulation of the…

  12. Planetary Quarantine Activities

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The activities of the Planetary Quarantine Department at Sandia Laboratories during the period April 1965 through June 1972 are summarized. Included are the rationale, the methods, and the results of modeling and experimentation used in dry heat, radiation, thermoradiation, and chemical sterilization studies. Publications describing these activities and accounts of closely related research are also furnished.

  13. Student Activities. Managing Liability.

    ERIC Educational Resources Information Center

    Bennett, Barbara; And Others

    This monograph suggests ways that college or university administrations can undertake a systematic and careful review of the risks posed by students' activities. Its purpose is to provide guidance in integrating the risk management process into a school's existing approaches to managing student organizations and activities. It is noted that no…

  14. Reflections on Activity Theory

    ERIC Educational Resources Information Center

    Bakhurst, David

    2009-01-01

    It is sometimes suggested that activity theory represents the most important legacy of Soviet philosophy and psychology. But what exactly "is" activity theory? The canonical account in the West is given by Engestrom, who identifies three stages in the theory's development: from Vygotsky's insights, through Leontiev's articulation of the…

  15. Activation of fly ash

    DOEpatents

    Corbin, David R.; Velenyi, Louis J.; Pepera, Marc A.; Dolhyj, Serge R.

    1986-01-01

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  16. Laboratory Activities in Israel

    ERIC Educational Resources Information Center

    Mamlok-Naaman, Rachel; Barnea, Nitza

    2012-01-01

    Laboratory activities have long had a distinctive and central role in the science curriculum, and science educators have suggested that many benefits accrue from engaging students in science laboratory activities. Many research studies have been conducted to investigate the educational effectiveness of laboratory work in science education in…

  17. Warm-Up Activities.

    ERIC Educational Resources Information Center

    Mingguang, Yang

    1999-01-01

    Discusses how warm-up activities can help to make the English-as-a-foreign-language classroom a lively and interesting place. Warm-up activities are games carried out at the beginning of each class to motivate students to make good use of class time. (Author/VWL)

  18. Science World Activities Book.

    ERIC Educational Resources Information Center

    Wisconsin Academy of Sciences, Arts and Letters, Madison.

    This document consists of three sections. Section I contains 19 activities developed by master teachers for the Science World '84 summer science program. These activities focus on studies involving airplane controls, trash bag kites, computers, meteorology, compass orienteering, soils, aquatic ecosystems, bogs, and others. Objectives, materials…

  19. Coordinating Shared Activities

    NASA Technical Reports Server (NTRS)

    Clement, Bradley

    2004-01-01

    Shared Activity Coordination (ShAC) is a computer program for planning and scheduling the activities of an autonomous team of interacting spacecraft and exploratory robots. ShAC could also be adapted to such terrestrial uses as helping multiple factory managers work toward competing goals while sharing such common resources as floor space, raw materials, and transports. ShAC iteratively invokes the Continuous Activity Scheduling Planning Execution and Replanning (CASPER) program to replan and propagate changes to other planning programs in an effort to resolve conflicts. A domain-expert specifies which activities and parameters thereof are shared and reports the expected conditions and effects of these activities on the environment. By specifying these conditions and effects differently for each planning program, the domain-expert subprogram defines roles that each spacecraft plays in a coordinated activity. The domain-expert subprogram also specifies which planning program has scheduling control over each shared activity. ShAC enables sharing of information, consensus over the scheduling of collaborative activities, and distributed conflict resolution. As the other planning programs incorporate new goals and alter their schedules in the changing environment, ShAC continually coordinates to respond to unexpected events.

  20. Nutrition Activities Resource Guide.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Div. of Special Education.

    The resource guide suggests activities to help special education students make appropriate choices about their nutritional habits. It is explained that the activities can be infused into other curriculum areas. The guide consists of five themes and includes performance objectives for each: foods eaten at school (planning a school lunch, keeping a…

  1. ZOOMsci Activity Guide.

    ERIC Educational Resources Information Center

    Wade, Meredith

    This activity guide is based on the Public Broadcasting System's (PBS) program "ZOOM." It is designed for educators with activities that are categorized into three themes: (1) Things That Go, which includes "Air" which explores air pressure, "Rubber Bands" which discovers the potential energy of rubber bands,…

  2. Students Active in Leadership.

    ERIC Educational Resources Information Center

    Brutcher, Robert

    2001-01-01

    Describes SAIL (Students Active in Leadership) as a school-based, youth-directed group. States that the program helps teenagers learn leadership skills by developing and implementing community service activities. SAIL finds partners with whom to collaborate among local businesses, government, and health associations, and these partners provide the…

  3. Emotionally Intense Science Activities

    ERIC Educational Resources Information Center

    King, Donna; Ritchie, Stephen; Sandhu, Maryam; Henderson, Senka

    2015-01-01

    Science activities that evoke positive emotional responses make a difference to students' emotional experience of science. In this study, we explored 8th Grade students' discrete emotions expressed during science activities in a unit on Energy. Multiple data sources including classroom videos, interviews and emotion diaries completed at the end of…

  4. Rainy Day Activities.

    ERIC Educational Resources Information Center

    Texas Child Care, 1997

    1997-01-01

    Experienced caregivers plan ahead for rainy days. This article describes specific rainy day activities for young children, such as books and crafts to learn about rain (rain in a jar, making a rainbow), simple cooking activities (taffy pull, cinnamon candy tea), and games (mummy wrap, hunt the thimble, rain lotto). (EV)

  5. Choreography of AMPK activation.

    PubMed

    Langendorf, Christopher G; Kemp, Bruce E

    2015-01-01

    A recent study published in Cell Research by Li and colleagues reports a detailed biophysical and structural study of AMPK's intra-molecular interactions during activation. By employing subunit tagging and proximity analysis with the aid of AlphaScreen instrumentation, Li et al. add to our understanding of the choreography of activation of AMPK by both nucleotides and phosphorylation.

  6. Activities: More Calculator Capers.

    ERIC Educational Resources Information Center

    Schmalz, Rosemary

    1983-01-01

    Provided is an activity designed to give grades 7-12 students opportunities to discover numerical patterns and to derive general conclusions from observing data. The activity focuses attention on patterns in products such as 33x34, 333x334, and 3333x3334. Three worksheets and answers are included. (JN)

  7. Curriculum Activities on Aging.

    ERIC Educational Resources Information Center

    Schmall, Vicki L.; Benge, Nancy

    This paper contains learning activities on aging for use with elementary, high school, and university students in health, family relationships, social studies, and art courses. The activities are intended to help youth develop a more realistic understanding of the aging process and to become aware of both the problems and benefits associated with…

  8. Rainy Day Activities.

    ERIC Educational Resources Information Center

    Texas Child Care, 1997

    1997-01-01

    Experienced caregivers plan ahead for rainy days. This article describes specific rainy day activities for young children, such as books and crafts to learn about rain (rain in a jar, making a rainbow), simple cooking activities (taffy pull, cinnamon candy tea), and games (mummy wrap, hunt the thimble, rain lotto). (EV)

  9. Activity Book: Ocean Ecology.

    ERIC Educational Resources Information Center

    Learning, 1992

    1992-01-01

    Presents a collection of activities to help elementary students study ocean ecology. The activities have students investigate ocean inhabitants, analyze animal adaptations, examine how temperature and saltiness affect ocean creatures, and learn about safeguarding the sea. Student pages offer reproducible learning sheets. (SM)

  10. [Field Learning Activities].

    ERIC Educational Resources Information Center

    Nolde Forest Environmental Education Center, Reading, PA.

    Seventy field activities, pertinent to outdoor, environmental studies, are described in this compilation. Designed for elementary and junior high school students, the activities cover many discipline areas--science, social studies, language arts, health, history, mathematics, and art--and many are multidisciplinary in use. Topics range from soil…

  11. Active and Healthy Schools

    ERIC Educational Resources Information Center

    Ball, Stephen; Kovarik, Jessica; Leidy, Heather

    2015-01-01

    The Active and Healthy School Program (AHS) can be used to alter the culture and environment of a school to help children make healthier choices. The purpose of this study was to determine the effectiveness of AHS to increase physical activity while decreasing total screen time, increase healthy food choices, and improve knowledge about physical…

  12. Activating Event Knowledge

    ERIC Educational Resources Information Center

    Hare, Mary; Jones, Michael; Thomson, Caroline; Kelly, Sarah; McRae, Ken

    2009-01-01

    An increasing number of results in sentence and discourse processing demonstrate that comprehension relies on rich pragmatic knowledge about real-world events, and that incoming words incrementally activate such knowledge. If so, then even outside of any larger context, nouns should activate knowledge of the generalized events that they denote or…

  13. Calculator-Active Materials.

    ERIC Educational Resources Information Center

    Crow, Tracy, Ed.; Harris, Julia, Ed.

    1997-01-01

    This journal contains brief descriptions of calculator-active materials that were found using Resource Finder, the searchable online catalog of curriculum resources from the Eisenhower National Clearinghouse (ENC). It features both the calculators themselves and the activity books that are used with them. Among the calculators included are those…

  14. Learning Activities for Toddlers.

    ERIC Educational Resources Information Center

    Texas Child Care, 1996

    1996-01-01

    Suggests activities to help toddlers develop skills in the four important areas of self-help, creativity, world mastery, and coordination. Activities include hand washing, button practice, painting, movement and music, bubble making, creation of a nature mural, and a shoe print trail. (TJQ)

  15. The Journal Synthesizing Activity.

    ERIC Educational Resources Information Center

    Garber, Zev

    The journal synthesizing activity is intended to combine aspects of the formal essay with that of a diary. Activities associated with lecture topics are written up as short journal entries of approximately five typewritten pages and are turned in during the weekly class session at which the related topic is being discussed. The journal project…

  16. Laboratory Activities in Israel

    ERIC Educational Resources Information Center

    Mamlok-Naaman, Rachel; Barnea, Nitza

    2012-01-01

    Laboratory activities have long had a distinctive and central role in the science curriculum, and science educators have suggested that many benefits accrue from engaging students in science laboratory activities. Many research studies have been conducted to investigate the educational effectiveness of laboratory work in science education in…

  17. Nutrition Activities Resource Guide.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Div. of Special Education.

    The resource guide suggests activities to help special education students make appropriate choices about their nutritional habits. It is explained that the activities can be infused into other curriculum areas. The guide consists of five themes and includes performance objectives for each: foods eaten at school (planning a school lunch, keeping a…

  18. Active and Healthy Schools

    ERIC Educational Resources Information Center

    Ball, Stephen; Kovarik, Jessica; Leidy, Heather

    2015-01-01

    The Active and Healthy School Program (AHS) can be used to alter the culture and environment of a school to help children make healthier choices. The purpose of this study was to determine the effectiveness of AHS to increase physical activity while decreasing total screen time, increase healthy food choices, and improve knowledge about physical…

  19. Learning Activities for Toddlers.

    ERIC Educational Resources Information Center

    Texas Child Care, 1996

    1996-01-01

    Suggests activities to help toddlers develop skills in the four important areas of self-help, creativity, world mastery, and coordination. Activities include hand washing, button practice, painting, movement and music, bubble making, creation of a nature mural, and a shoe print trail. (TJQ)

  20. Metastasis and AKT activation.

    PubMed

    Qiao, Meng; Sheng, Shijie; Pardee, Arthur B

    2008-10-01

    Metastasis is responsible for 90% of cancer patient deaths. More information is needed about the molecular basis for its potential detection and treatment. The activated AKT kinase is necessary for many events of the metastatic pathway including escape of cells from the tumor's environment, into and then out of the circulation, activation of proliferation, blockage of apoptosis, and activation of angiogenesis. A series of steps leading to metastatic properties can be initiated upon activation of AKT by phosphorylation on Ser-473. These findings lead to the question of how this activation is connected to metastasis. Activated AKT phosphorylates GSK-3beta causing its proteolytic removal. This increases stability of the negative transcription factor SNAIL, thereby decreasing transcription of the transmembrane protein E-cadherin that forms adhesions between adjacent cells, thereby permitting their detachment. How is AKT hyperactivated in metastatic cells? Increased PI3K or TORC2 kinase activity- or decreased PHLPP phosphatase could be responsible. Furthermore, a positive feedback mechanism is that the decrease of E-cadherin lowers PTEN and thereby increases PIP3, further activating AKT and metastasis.

  1. Activities of the ILO.

    ERIC Educational Resources Information Center

    Labour Education, 1984

    1984-01-01

    Seven articles on International Labour Organization (ILO) activities cover study groups at ILO headquarters, a Philippine rural workers seminar, women's participation in Central American union activities, worksite courses in India, and seminars and symposia in Cape Verde, Mauritius, and Sierra Leone. (SK)

  2. Aging and Semantic Activation.

    ERIC Educational Resources Information Center

    Howard, Darlene V.

    Three studies tested the theory that long term memory consists of a semantically organized network of concept nodes interconnected by leveled associations or relations, and that when a stimulus is processed, the corresponding concept node is assumed to be temporarily activated and this activation spreads to nearby semantically related nodes. In…

  3. Active Students in Webinars

    ERIC Educational Resources Information Center

    Kolås, Line; Nordseth, Hugo; Yri, Jørgen Sørlie

    2015-01-01

    To ensure student activity in webinars we have defined 10 learning tasks focusing on production and communication e.g. collaborative writing, discussion and polling, and investigated how the technology supports the learning activities. The three project partners in the VisPed-project use different video-conferencing systems, and we analyzed how it…

  4. Emotionally Intense Science Activities

    ERIC Educational Resources Information Center

    King, Donna; Ritchie, Stephen; Sandhu, Maryam; Henderson, Senka

    2015-01-01

    Science activities that evoke positive emotional responses make a difference to students' emotional experience of science. In this study, we explored 8th Grade students' discrete emotions expressed during science activities in a unit on Energy. Multiple data sources including classroom videos, interviews and emotion diaries completed at the end of…

  5. Target-cell-specific short-term plasticity in local circuits.

    PubMed

    Blackman, Arne V; Abrahamsson, Therese; Costa, Rui Ponte; Lalanne, Txomin; Sjöström, P Jesper

    2013-12-06

    Short-term plasticity (STP) denotes changes in synaptic strength that last up to tens of seconds. It is generally thought that STP impacts information transfer across synaptic connections and may thereby provide neurons with, for example, the ability to detect input coherence, to maintain stability and to promote synchronization. STP is due to a combination of mechanisms, including vesicle depletion and calcium accumulation in synaptic terminals. Different forms of STP exist, depending on many factors, including synapse type. Recent evidence shows that synapse dependence holds true even for connections that originate from a single presynaptic cell, which implies that postsynaptic target cell type can determine synaptic short-term dynamics. This arrangement is surprising, since STP itself is chiefly due to presynaptic mechanisms. Target-specific synaptic dynamics in addition imply that STP is not a bug resulting from synapses fatiguing when driven too hard, but rather a feature that is selectively implemented in the brain for specific functional purposes. As an example, target-specific STP results in sequential somatic and dendritic inhibition in neocortical and hippocampal excitatory cells during high-frequency firing. Recent studies also show that the Elfn1 gene specifically controls STP at some synapse types. In addition, presynaptic NMDA receptors have been implicated in synapse-specific control of synaptic dynamics during high-frequency activity. We argue that synapse-specific STP deserves considerable further study, both experimentally and theoretically, since its function is not well known. We propose that synapse-specific STP has to be understood in the context of the local circuit, which requires combining different scientific disciplines ranging from molecular biology through electrophysiology to computer modeling.

  6. Target-cell-specific short-term plasticity in local circuits

    PubMed Central

    Blackman, Arne V.; Abrahamsson, Therese; Costa, Rui Ponte; Lalanne, Txomin; Sjöström, P. Jesper

    2013-01-01

    Short-term plasticity (STP) denotes changes in synaptic strength that last up to tens of seconds. It is generally thought that STP impacts information transfer across synaptic connections and may thereby provide neurons with, for example, the ability to detect input coherence, to maintain stability and to promote synchronization. STP is due to a combination of mechanisms, including vesicle depletion and calcium accumulation in synaptic terminals. Different forms of STP exist, depending on many factors, including synapse type. Recent evidence shows that synapse dependence holds true even for connections that originate from a single presynaptic cell, which implies that postsynaptic target cell type can determine synaptic short-term dynamics. This arrangement is surprising, since STP itself is chiefly due to presynaptic mechanisms. Target-specific synaptic dynamics in addition imply that STP is not a bug resulting from synapses fatiguing when driven too hard, but rather a feature that is selectively implemented in the brain for specific functional purposes. As an example, target-specific STP results in sequential somatic and dendritic inhibition in neocortical and hippocampal excitatory cells during high-frequency firing. Recent studies also show that the Elfn1 gene specifically controls STP at some synapse types. In addition, presynaptic NMDA receptors have been implicated in synapse-specific control of synaptic dynamics during high-frequency activity. We argue that synapse-specific STP deserves considerable further study, both experimentally and theoretically, since its function is not well known. We propose that synapse-specific STP has to be understood in the context of the local circuit, which requires combining different scientific disciplines ranging from molecular biology through electrophysiology to computer modeling. PMID:24367330

  7. Emotionally Intense Science Activities

    NASA Astrophysics Data System (ADS)

    King, Donna; Ritchie, Stephen; Sandhu, Maryam; Henderson, Senka

    2015-08-01

    Science activities that evoke positive emotional responses make a difference to students' emotional experience of science. In this study, we explored 8th Grade students' discrete emotions expressed during science activities in a unit on Energy. Multiple data sources including classroom videos, interviews and emotion diaries completed at the end of each lesson were analysed to identify individual student's emotions. Results from two representative students are presented as case studies. Using a theoretical perspective drawn from theories of emotions founded in sociology, two assertions emerged. First, during the demonstration activity, students experienced the emotions of wonder and surprise; second, during a laboratory activity, students experienced the intense positive emotions of happiness/joy. Characteristics of these activities that contributed to students' positive experiences are highlighted. The study found that choosing activities that evoked strong positive emotional experiences, focused students' attention on the phenomenon they were learning, and the activities were recalled positively. Furthermore, such positive experiences may contribute to students' interest and engagement in science and longer term memorability. Finally, implications for science teachers and pre-service teacher education are suggested.

  8. Active touch sensing

    PubMed Central

    Prescott, Tony J.; Diamond, Mathew E.; Wing, Alan M.

    2011-01-01

    Active sensing systems are purposive and information-seeking sensory systems. Active sensing usually entails sensor movement, but more fundamentally, it involves control of the sensor apparatus, in whatever manner best suits the task, so as to maximize information gain. In animals, active sensing is perhaps most evident in the modality of touch. In this theme issue, we look at active touch across a broad range of species from insects, terrestrial and marine mammals, through to humans. In addition to analysing natural touch, we also consider how engineering is beginning to exploit physical analogues of these biological systems so as to endow robots with rich tactile sensing capabilities. The different contributions show not only the varieties of active touch—antennae, whiskers and fingertips—but also their commonalities. They explore how active touch sensing has evolved in different animal lineages, how it serves to provide rapid and reliable cues for controlling ongoing behaviour, and even how it can disintegrate when our brains begin to fail. They demonstrate that research on active touch offers a means both to understand this essential and primary sensory modality, and to investigate how animals, including man, combine movement with sensing so as to make sense of, and act effectively in, the world. PMID:21969680

  9. Active touch sensing.

    PubMed

    Prescott, Tony J; Diamond, Mathew E; Wing, Alan M

    2011-11-12

    Active sensing systems are purposive and information-seeking sensory systems. Active sensing usually entails sensor movement, but more fundamentally, it involves control of the sensor apparatus, in whatever manner best suits the task, so as to maximize information gain. In animals, active sensing is perhaps most evident in the modality of touch. In this theme issue, we look at active touch across a broad range of species from insects, terrestrial and marine mammals, through to humans. In addition to analysing natural touch, we also consider how engineering is beginning to exploit physical analogues of these biological systems so as to endow robots with rich tactile sensing capabilities. The different contributions show not only the varieties of active touch--antennae, whiskers and fingertips--but also their commonalities. They explore how active touch sensing has evolved in different animal lineages, how it serves to provide rapid and reliable cues for controlling ongoing behaviour, and even how it can disintegrate when our brains begin to fail. They demonstrate that research on active touch offers a means both to understand this essential and primary sensory modality, and to investigate how animals, including man, combine movement with sensing so as to make sense of, and act effectively in, the world.

  10. Active optical zoom system

    DOEpatents

    Wick, David V.

    2005-12-20

    An active optical zoom system changes the magnification (or effective focal length) of an optical imaging system by utilizing two or more active optics in a conventional optical system. The system can create relatively large changes in system magnification with very small changes in the focal lengths of individual active elements by leveraging the optical power of the conventional optical elements (e.g., passive lenses and mirrors) surrounding the active optics. The active optics serve primarily as variable focal-length lenses or mirrors, although adding other aberrations enables increased utility. The active optics can either be LC SLMs, used in a transmissive optical zoom system, or DMs, used in a reflective optical zoom system. By appropriately designing the optical system, the variable focal-length lenses or mirrors can provide the flexibility necessary to change the overall system focal length (i.e., effective focal length), and therefore magnification, that is normally accomplished with mechanical motion in conventional zoom lenses. The active optics can provide additional flexibility by allowing magnification to occur anywhere within the FOV of the system, not just on-axis as in a conventional system.

  11. THE ACTIVE CENTAURS

    SciTech Connect

    Jewitt, David

    2009-05-15

    The Centaurs are recent escapees from the Kuiper Belt that are destined either to meet fiery oblivion in the hot inner regions of the solar system or to be ejected to the interstellar medium by gravitational scattering from the giant planets. Dynamically evolved Centaurs, when captured by Jupiter and close enough to the Sun for near-surface water ice to sublimate, are conventionally labeled as 'short-period' (specifically, Jupiter-family) comets. Remarkably, some Centaurs show comet-like activity even when far beyond the orbit of Jupiter, suggesting mass loss driven by a process other than the sublimation of water ice. We observed a sample of 23 Centaurs and found nine to be active, with mass-loss rates measured from several kg s{sup -1} to several tonnes s{sup -1}. Considered as a group, we find that the 'active Centaurs' in our sample have perihelia smaller than the inactive Centaurs (median 5.9 AU versus 8.7 AU), and smaller than the median perihelion distance computed for all known Centaurs (12.4 AU). This suggests that their activity is thermally driven. We consider several possibilities for the origin of the mass loss from the active Centaurs. Most are too cold for activity at the observed levels to originate via the sublimation of crystalline water ice. Solid carbon monoxide and carbon dioxide have the opposite problem: they are so volatile that they should drive activity in Centaurs at much larger distances than observed. We consider the possibility that activity in the Centaurs is triggered by the conversion of amorphous ice into the crystalline form accompanied by the release of trapped gases, including carbon monoxide. By imposing the condition that crystallization should occur when the crystallization time is shorter than the orbital period we find a qualitative match to the perihelion distribution of the active Centaurs and conclude that the data are consistent with the hypothesis that the Centaurs contain amorphous ice.

  12. Activity in the hippocampus and neocortical working memory regions predicts successful associative memory for temporally-discontiguous events

    PubMed Central

    Hales, J. B.; Brewer, J. B.

    2010-01-01

    Models of mnemonic function suggest that the hippocampus binds temporally-discontiguous events in memory (Wallenstein, G.V., Eichenbaum, H., & Hasselmo, M.E., (1998). The hippocampus as an associator of discontiguous events. Trends Neurosci, 21 (8), 317–323), which has been supported by recent studies in humans. Less is known, however, about the involvement of working memory in bridging the temporal gap between to-be-associated events. In this study, subsequent memory for associations between temporally-discontiguous stimuli was examined using functional magnetic resonance imaging. In the scanner, subjects were instructed to remember sequentially-presented images. Occasionally, a plus-sign was presented during the interstimulus-interval between two images, instructing subjects to associate the two images as a pair. Following the scan, subjects identified remembered images and their pairs. Images following the plus-sign were separated into trials in which items were later recognized and the pair remembered, recognized and the pair forgotten, or not recognized. Blood-oxygen-level-dependent responses were measured to identify regions where response amplitude predicted subsequent associative- or item-memory. Distinct neocortical regions were involved in each memory condition, where activity in bilateral frontal and parietal regions predicted memory for associative-information and bilateral occipital and medial frontal regions for item-information. While activity in posterior regions of the medial temporal lobe showed an intermediate response predicting memory for both conditions, bilateral hippocampal activity only predicted associative memory. PMID:20667491

  13. Extreme brain events: Higher-order statistics of brain resting activity and its relation with structural connectivity

    NASA Astrophysics Data System (ADS)

    Amor, T. A.; Russo, R.; Diez, I.; Bharath, P.; Zirovich, M.; Stramaglia, S.; Cortes, J. M.; de Arcangelis, L.; Chialvo, D. R.

    2015-09-01

    The brain exhibits a wide variety of spatiotemporal patterns of neuronal activity recorded using functional magnetic resonance imaging as the so-called blood-oxygenated-level-dependent (BOLD) signal. An active area of work includes efforts to best describe the plethora of these patterns evolving continuously in the brain. Here we explore the third-moment statistics of the brain BOLD signals in the resting state as a proxy to capture extreme BOLD events. We find that the brain signal exhibits typically nonzero skewness, with positive values for cortical regions and negative values for subcortical regions. Furthermore, the combined analysis of structural and functional connectivity demonstrates that relatively more connected regions exhibit activity with high negative skewness. Overall, these results highlight the relevance of recent results emphasizing that the spatiotemporal location of the relatively large-amplitude events in the BOLD time series contains relevant information to reproduce a number of features of the brain dynamics during resting state in health and disease.

  14. A Preliminary Study of Functional Brain Activation among Marijuana Users during Performance of a Virtual Water Maze Task

    PubMed Central

    Sneider, Jennifer Tropp; Gruber, Staci A.; Rogowska, Jadwiga; Silveri, Marisa M.; Yurgelun-Todd, Deborah A.

    2013-01-01

    Numerous studies have reported neurocognitive impairments associated with chronic marijuana use. Given that the hippocampus contains a high density of cannabinoid receptors, hippocampal-mediated cognitive functions, including visuospatial memory, may have increased vulnerability to chronic marijuana use. Thus, the current study examined brain activation during the performance of a virtual analogue of the classic Morris water maze task in 10 chronic marijuana (MJ) users compared to 18 nonusing (NU) comparison subjects. Imaging data were acquired using blood oxygen level-dependent (BOLD) functional MRI at 3.0 Tesla during retrieval (hidden platform) and motor control (visible platform) conditions. While task performance on learning trials was similar between groups, MJ users demonstrated a deficit in memory retrieval. For BOLD fMRI data, NU subjects exhibited greater activation in the right parahippocampal gyrus and cingulate gyrus compared to the MJ group for the Retrieval-Motor Control contrast (NU > MJ). These findings suggest that hypoactivation in MJ users may be due to differences in the efficient utilization of neuronal resources during the retrieval of memory. Given the paucity of data on visuospatial memory function in MJ users, these findings may help elucidate the neurobiological effects of marijuana on brain activation during memory retrieval. PMID:23951549

  15. Post-conventional moral reasoning is associated with increased ventral striatal activity at rest and during task.

    PubMed

    Fang, Zhuo; Jung, Wi Hoon; Korczykowski, Marc; Luo, Lijuan; Prehn, Kristin; Xu, Sihua; Detre, John A; Kable, Joseph W; Robertson, Diana C; Rao, Hengyi

    2017-08-02

    People vary considerably in moral reasoning. According to Kohlberg's theory, individuals who reach the highest level of post-conventional moral reasoning judge moral issues based on deeper principles and shared ideals rather than self-interest or adherence to laws and rules. Recent research has suggested the involvement of the brain's frontostriatal reward system in moral judgments and prosocial behaviors. However, it remains unknown whether moral reasoning level is associated with differences in reward system function. Here, we combined arterial spin labeling perfusion and blood oxygen level-dependent functional magnetic resonance imaging and measured frontostriatal reward system activity both at rest and during a sequential risky decision making task in a sample of 64 participants at different levels of moral reasoning. Compared to individuals at the pre-conventional and conventional level of moral reasoning, post-conventional individuals showed increased resting cerebral blood flow in the ventral striatum and ventromedial prefrontal cortex. Cerebral blood flow in these brain regions correlated with the degree of post-conventional thinking across groups. Post-conventional individuals also showed greater task-induced activation in the ventral striatum during risky decision making. These findings suggest that high-level post-conventional moral reasoning is associated with increased activity in the brain's frontostriatal system, regardless of task-dependent or task-independent states.

  16. Brain activity for tactile allodynia: a longitudinal awake rat functional magnetic resonance imaging study tracking emergence of neuropathic pain.

    PubMed

    Chang, Pei-Ching; Centeno, Maria Virginia; Procissi, Daniel; Baria, Alex; Apkarian, A Vania

    2017-03-01

    Tactile allodynia, a condition in which innocuous mechanical stimuli are perceived as painful, is a common feature of chronic pain. However, how the brain reorganizes in relation to the emergence of tactile allodynia is still largely unknown. This may stem from the fact that experiments in humans are cross-sectional in nature, whereas animal brain imaging studies typically require anaesthesia rendering the brain incapable of consciously sensing or responding to pain. In this longitudinal functional magnetic resonance imaging study in awake rats, we tracked brain activity with the development of tactile allodynia. Before injury, innocuous air-puff stimuli evoked a distributed sensory network of activations, including contralateral somatosensory cortices, thalamus, insula, and cingulate cortex. Moreover, the primary somatosensory cortex displayed a graded response tracking air-puff stimulus intensities. After neuropathic injury, and for stimuli in which the intensity exceeded the paw withdrawal threshold (evoking tactile allodynia), the blood oxygenation level-dependent response in the primary somatosensory cortex was equivalent to that evoked by the identical stimulus before injury. In contrast, nucleus accumbens and prefrontal brain areas displayed abnormal activity to normally innocuous stimuli when such stimuli induced tactile allodynia at 28 days after peripheral nerve injury, which had not been the case at 5 days after injury. Our data indicate that tactile allodynia-related nociceptive inputs are not observable in the primary somatosensory cortex BOLD response. Instead, our data suggest that, in time, tactile allodynia differentially engages neural circuits that regulate the affective and motivational components of pain.

  17. Integration of neural networks activated by amphetamine in females with different estrogen levels: a functional imaging study in awake rats.

    PubMed

    Madularu, Dan; Yee, Jason R; Kenkel, William M; Moore, Kelsey A; Kulkarni, Praveen; Shams, Waqqas M; Ferris, Craig F; Brake, Wayne G

    2015-06-01

    Previous studies demonstrate that schizophrenia symptomatology in women is dependent upon estrogen levels. Estrogen has beneficial properties when administered in conjunction with antipsychotics, and estrogen also alters, in rats, dopamine neurotransmission, which is a common target of all antipsychotic medications, suggesting a possible interaction between the two. The aim of the current study was to investigate this possible interaction using functional magnetic resonance imaging in awake, female rats. Amphetamine-sensitized, ovariectomized rats receiving no, chronic low, or phasic high levels of estradiol replacement were used, and changes in blood-oxygen-level-dependent (BOLD) signal were recorded over time in response to an acute amphetamine injection. Increasing levels of estradiol enhanced BOLD activation in pathways previously known to be implicated in schizophrenia symptomatology, such as the mesocorticolimbic, habenular and olfactory pathways, as well as more widespread areas. We propose here the first comprehensive "amphetamine activation map" integrating brain regions where amphetamine-related BOLD activity is influenced by estrogen levels in sensitized female rats. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Real-time imaging of brain areas involved in the generation of spontaneous skin sympathetic nerve activity at rest.

    PubMed

    James, Cheree; Henderson, Luke; Macefield, Vaughan G

    2013-07-01

    In thermoneutral conditions resting skin sympathetic nerve activity (SSNA) is related to the level of arousal and emotional state. The brain regions responsible for the generation of spontaneous SSNA are not known. In the present study we used concurrent recordings of SSNA and brain activity in awake humans to identify cortical and subcortical areas involved in the generation of spontaneous SSNA in 13 healthy subjects. Blood oxygen level dependent signal intensity increases covaried with SSNA in the left thalamus in the region of the ventromedial nucleus, the left posterior and right anterior insula, the right orbitofrontal cortex, the right frontal cortex, and bilaterally in the mid-cingulate cortex and precuneus. Functional connectivity analysis revealed a strong positive coupling between the right orbitofrontal cortex and the right anterior insula. Furthermore, signal intensity changes within the precuneus were temporally coupled to the left anterior and posterior insula, cerebellum, cingulate cortex and thalamus. It has been hypothesized that these brain regions monitor the internal state of the body and may regulate emotional state changes. Our results show that the activities within these regions are also correlated to spontaneous fluctuations in SSNA. Copyright © 2013 Elsevier Inc. All rights reserved.

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

    PubMed

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

    2017-04-15

    Cross-modal plasticity within the visual and auditory cortices of early binocularly blind macaques is not well studied. In this study, four healthy neonatal macaques were assigned to group A (control group) or group B (binocularly blind group). Sixteen months later, blood oxygenation level-dependent functional imaging (BOLD-fMRI) was conducted to examine the activation in the visual and auditory cortices of each macaque while being tested using pure tones as auditory stimuli. The changes in the BOLD response in the visual and auditory cortices of all macaques were compared with immunofluorescence staining findings. Compared with group A, greater BOLD activity was observed in the bilateral visual cortices of group B, and this effect was particularly obvious in the right visual cortex. In addition, more activated volumes were found in the bilateral auditory cortices of group B than of group A, especially in the right auditory cortex. These findings were consistent with the fact that there were more c-Fos-positive cells in the bilateral visual and auditory cortices of group B compared with group A (p < 0.05). In conclusion, the bilateral visual cortices of binocularly blind macaques can be reorganized to process auditory stimuli after visual deprivation, and this effect is more obvious in the right than the left visual cortex. These results indicate the establishment of cross-modal plasticity within the visual and auditory cortices.

  20. Differences and similarities on neuronal activities of people being happily and unhappily in love: a functional magnetic resonance imaging study.

    PubMed

    Stoessel, Christina; Stiller, Juliane; Bleich, Stefan; Bönsch, Dominikus; Boensch, Dominikus; Doerfler, Arnd; Garcia, Meritxell; Richter-Schmidinger, Tanja; Kornhuber, Johannes; Forster, Clemens

    2011-01-01

    Brain activity was studied in grief following frustrated love compared to romantic love, and it was hypothesized that unhappy lovers compared to happy lovers would have decreased brain activity in regions specific to emotional and reward circuits, such as frontal brain areas, anterior cingulate cortex (ACC), bilateral insula or posterior cingulate cortex (PCC). Twelve volunteers intensely in love and 12 volunteers recently separated from their romantic partners were scanned performing 3 runs of functional magnetic resonance imaging acquisition. Subjects viewed partner pictures versus erotic pictures during the first run of the scanning process, autobiographical pictures versus neutral pictures during the second and autobiographical texts versus neutral texts during the third run. The Passionate Love Scale (PLS) and the Beck Depression Inventory (BDI) were additionally recorded. Decreased brain activity in unhappy lovers compared to happy lovers occurred in frontal areas, ACC and PCC and bilateral insula. Unhappy lovers also revealed clinical depressive symptoms in the BDI. Unhappy lovers compared to happy lovers exhibited clinical depressive symptoms and reduced blood oxygen level dependency changes in a brain network which has been described as being involved in major depression. This might be a cue for the close relationship between grief and depression. Copyright © 2011 S. Karger AG, Basel.

  1. Simultaneous EEG/functional magnetic resonance imaging at 4 Tesla: correlates of brain activity to spontaneous alpha rhythm during relaxation.

    PubMed

    Difrancesco, Mark W; Holland, Scott K; Szaflarski, Jerzy P

    2008-10-01

    : Simultaneous EEG and functional magnetic resonance imaging have been applied to the study of brain states associated with alpha waves using a magnetic field strength of 1.5 Tesla and has been shown in recent years to be feasible up to 3 Tesla for other applications. This study demonstrates this technique's continued viability at a field strength of 4 Tesla, affording a proportionally greater sensitivity to changes in Blood Oxygen Level Dependent (BOLD) signal. In addition, for the study of alpha correlations, the authors used a larger number of subjects and scanning sessions than in the previous work. Random effects group regression analysis of 35 EEG/functional magnetic resonance imaging sessions against occipital alpha magnitude in a relaxed state detected bilateral widespread activation of dorsal thalamus and portions of the anterior cingulate and cerebellum. In the same group analysis, deactivations arose predominantly in the fusiform and adjacent visual association areas with a small activation cluster also detected in dorsolateral prefrontal cortex. This pattern is consistent with a correspondence between alpha magnitude variations and resting state network dynamics ascertained by recent studies of low frequency spontaneous BOLD fluctuations. The central role of the thalamus in resting state networks correlated with alpha activity is highlighted. Demonstrating the applicability of simultaneous EEG/functional magnetic resonance imaging up to 4 Tesla is particularly important for clinically relevant research involving challenging spontaneous EEG abnormalities, such as those of epilepsy.

  2. Unexpected global impact of VTA dopamine neuron activation as measured by opto-fMRI.

    PubMed

    Lohani, S; Poplawsky, A J; Kim, S-G; Moghaddam, B

    2017-04-01

    Dopamine neurons in the ventral tegmental area (VTA) are strongly implicated in cognitive and affective processing as well as in psychiatric disorders, including schizophrenia, depression, attention-deficit hyperactivity disorder and substance abuse disorders. In human studies, dopamine-related functions are routinely assessed using functional magnetic resonance imaging (fMRI) measures of blood oxygenation-level-dependent (BOLD) signals during the performance of dopamine-dependent tasks. There is, however, a critical void in our knowledge about whether and how activation of VTA dopamine neurons specifically influences regional or global fMRI signals. Here, we used optogenetics in Th::Cre rats to selectively stimulate VTA dopamine neurons while simultaneously measuring global hemodynamic changes using BOLD and cerebral blood volume-weighted (CBVw) fMRI. Phasic activation of VTA dopamine neurons increased BOLD and CBVw fMRI signals in VTA-innervated limbic regions, including the ventral striatum (nucleus accumbens). Surprisingly, basal ganglia regions that receive sparse or no VTA dopaminergic innervation, including the dorsal striatum and the globus pallidus, were also activated. In fact, the most prominent fMRI signal increase in the forebrain was observed in the dorsal striatum that is not traditionally associated with VTA dopamine neurotransmission. These data establish causation between phasic activation of VTA dopamine neurons and global fMRI signals. They further suggest that mesolimbic and non-limbic basal ganglia dopamine circuits are functionally connected and thus provide a potential novel framework for understanding dopamine-dependent functions and interpreting data obtained from human fMRI studies.

  3. Changes in brain activation in breast cancer patients depend on cognitive domain and treatment type

    PubMed Central

    Menning, Sanne; de Ruiter, Michiel B.; Veltman, Dick J.; Boogerd, Willem; Oldenburg, Hester S. A.; Reneman, Liesbeth

    2017-01-01

    Background Cognitive problems in breast cancer patients are common after systemic treatment, particularly chemotherapy. An increasing number of fMRI studies show altered brain activation in breast cancer patients after treatment, suggestive of neurotoxicity. Previous prospective fMRI studies administered a single cognitive task. The current study employed two task paradigms to evaluate whether treatment-induced changes depend on the probed cognitive domain. Methods Participants were breast cancer patients scheduled to receive systemic treatment (anthracycline-based chemotherapy +/- endocrine treatment, n = 28), or no systemic treatment (n = 24) and no-cancer controls (n = 31). Assessment took place before adjuvant treatment and six months after chemotherapy, or at similar intervals. Blood oxygen level dependent (BOLD) activation and performance were measured during an executive functioning task and an episodic memory task. Group-by-time interactions were analyzed using a flexible factorial design. Results Task performance did not differ between patient groups and did not change over time. Breast cancer patients who received systemic treatment, however, showed increased parietal activation compared to baseline with increasing executive functioning task load compared to breast cancer patients who did not receive systemic treatment. This hyperactivation was accompanied by worse physical functioning, higher levels of fatigue and more cognitive complaints. In contrast, in breast cancer patients who did not receive systemic treatment, parietal activation normalized over time compared to the other two groups. Conclusions Parietal hyperactivation after systemic treatment in the context of stable levels of executive task performance is compatible with a compensatory processing account of hyperactivation or maintain adequate performance levels. This over-recruitment of brain regions depends on the probed cognitive domain and may represent a response to decreased neural

  4. Cognitive priming in sung and instrumental music: activation of inferior frontal cortex.

    PubMed

    Tillmann, B; Koelsch, S; Escoffier, N; Bigand, E; Lalitte, P; Friederici, A D; von Cramon, D Y

    2006-07-15

    Neural correlates of the processing of musical syntax-like structures have been investigated via expectancy violation due to musically unrelated (i.e., unexpected) events in musical contexts. Previous studies reported the implication of inferior frontal cortex in musical structure processing. However - due to the strong musical manipulations - activations might be explained by sensory deviance detection or repetition priming. Our present study investigated neural correlates of musical structure processing with subtle musical violations in a musical priming paradigm. Instrumental and sung sequences ended on related and less-related musical targets. The material controlled sensory priming components, and differences in target processing required listeners' knowledge on musical structures. Participants were scanned with functional Magnetic Resonance Imaging (fMRI) while performing speeded phoneme and timbre identification judgments on the targets. Behavioral results acquired in the scanner replicated the facilitation effect of related over less-related targets. The blood oxygen level-dependent (BOLD) signal linked to target processing revealed activation of right inferior frontal areas (i.e., inferior frontal gyrus, frontal operculum, anterior insula) that was stronger for less-related than for related targets, and this was independent of the material carrying the musical structures. This outcome points to the implication of inferior frontal cortex in the processing of syntactic relations also for musical material and to its role in the processing and integration of sequential information over time. In addition to inferior frontal activation, increased activation was observed in orbital gyrus, temporal areas (anterior superior temporal gyrus, posterior superior temporal gyrus and sulcus, posterior middle temporal gyrus) and supramarginal gyrus.

  5. Changes in brain activation in breast cancer patients depend on cognitive domain and treatment type.

    PubMed

    Menning, Sanne; de Ruiter, Michiel B; Veltman, Dick J; Boogerd, Willem; Oldenburg, Hester S A; Reneman, Liesbeth; Schagen, Sanne B

    2017-01-01

    Cognitive problems in breast cancer patients are common after systemic treatment, particularly chemotherapy. An increasing number of fMRI studies show altered brain activation in breast cancer patients after treatment, suggestive of neurotoxicity. Previous prospective fMRI studies administered a single cognitive task. The current study employed two task paradigms to evaluate whether treatment-induced changes depend on the probed cognitive domain. Participants were breast cancer patients scheduled to receive systemic treatment (anthracycline-based chemotherapy +/- endocrine treatment, n = 28), or no systemic treatment (n = 24) and no-cancer controls (n = 31). Assessment took place before adjuvant treatment and six months after chemotherapy, or at similar intervals. Blood oxygen level dependent (BOLD) activation and performance were measured during an executive functioning task and an episodic memory task. Group-by-time interactions were analyzed using a flexible factorial design. Task performance did not differ between patient groups and did not change over time. Breast cancer patients who received systemic treatment, however, showed increased parietal activation compared to baseline with increasing executive functioning task load compared to breast cancer patients who did not receive systemic treatment. This hyperactivation was accompanied by worse physical functioning, higher levels of fatigue and more cognitive complaints. In contrast, in breast cancer patients who did not receive systemic treatment, parietal activation normalized over time compared to the other two groups. Parietal hyperactivation after systemic treatment in the context of stable levels of executive task performance is compatible with a compensatory processing account of hyperactivation or maintain adequate performance levels. This over-recruitment of brain regions depends on the probed cognitive domain and may represent a response to decreased neural integrity after systemic treatment. Overall

  6. Enhancing effects of flavored nutritive stimuli on cortical swallowing network activity

    PubMed Central

    Babaei, Arash; Kern, Mark; Antonik, Stephen; Mepani, Rachel; Ward, B. Douglas; Li, Shi-Jiang; Hyde, James

    2010-01-01

    A better understanding of the central control of the physiology of deglutition is necessary for devising interventions aimed at correcting pathophysiological conditions of swallowing. Positive modulation of the cortical swallowing network can have clinical ramifications in dysphagia due to central nervous system deficits. Our aim was to determine the effect of nutritive sensory input on the cortical swallowing network. In 14 healthy right-handed volunteers, we utilized a paradigm-driven protocol to quantify the number of activated voxels and their signal intensity within the left hemispheric cortical swallowing network by high-resolution functional MRI (fMRI) during five different swallowing conditions. Swallowing conditions included a dry swallow (saliva) and natural water-, lemon-, popcorn-, and chocolate-flavored liquid swallows. Each flavored liquid was presented simultaneously by its image, scent, and taste in random order and tested over three runs. fMRIs were analyzed in a blinded fashion. Average fMRI blood oxygenation level-dependent signal intensity and number of activated voxels during swallowing concurrent with nutritive gustatory, olfactory, and visual stimulations were significantly increased compared with dry/natural water swallows throughout the cortical swallowing network (P < 0.001 and P < 0.05, respectively). Subregion analysis showed the increased activity for flavored liquids in prefrontal, cingulate gyrus, and sensory/motor cortex, but not in precuneus and insula. Concurrent gustatory, olfactory, and visual nutritive stimulation enhances the activity of the cortical swallowing network. This finding may have clinical implications in management of swallowing disorders due to cortical lesions. PMID:20508154

  7. Altered Cerebellar Activity in Visceral Pain-Related Fear Conditioning in Irritable Bowel Syndrome.

    PubMed

    Claassen, J; Labrenz, F; Ernst, T M; Icenhour, A; Langhorst, J; Forsting, M; Timmann, D; Elsenbruch, S

    2017-04-01

    There is evidence to support a role of the cerebellum in emotional learning processes, which are demonstrably altered in patients with chronic pain. We tested if cerebellar activation is altered during visceral pain-related fear conditioning and extinction in irritable bowel syndrome (IBS). Cerebellar blood oxygenation level-dependent (BOLD) data from N = 17 IBS patients and N = 21 healthy controls, collected as part of a previous fMRI study, was reanalyzed utilizing an advanced normalizing method of the cerebellum. The differential fear conditioning paradigm consisted of acquisition, extinction, and reinstatement phases. During acquisition, two visual conditioned stimuli (CS) were presented either paired (CS+) or unpaired (CS-) with painful rectal distension as unconditioned stimulus (US). In the extinction phase, the CS+ and CS- were presented without US. For reinstatement, unpaired US presentations were followed by unpaired CS+ and CS- presentations. Group differences in cerebellar activation were analyzed for the contrasts CS+ > CS- and CS- > CS+. During acquisition, IBS patients revealed significantly enhanced cerebellar BOLD responses to pain-predictive (CS+) and safety (CS-) cues compared to controls (p < 0.05, family-wise error corrected). Increased activation was found in three main clusters, including the vermis (maximum in vermal lobule VI), intermediate cerebellum (maximum in lobule VIII), and the posterolateral cerebellar hemisphere (maximum in lobule VI). Areas overlapped for the contrasts CS+ > CS- and CS- > CS+. Group differences were most prominent in the contrast CS- > CS+. During extinction and reinstatement, no significant group differences were found. During visceral pain-related fear conditioning, IBS patients showed increased activations in circumscribed areas of the medial, intermediate, and lateral cerebellum. These areas are involved in autonomic, somatosensory, and cognitive functions and likely contribute to the different

  8. A novel technique for examining human brain activity associated with pedaling using fMRI.

    PubMed

    Mehta, Jay P; Verber, Matthew D; Wieser, Jon A; Schmit, Brian D; Schindler-Ivens, Sheila M

    2009-05-15

    Advances in neural imaging technologies, such as functional magnetic resonance imaging (fMRI), have made it possible to obtain images of human brain activity during motor tasks. However, technical challenges have made it difficult to image the brain during multijoint lower limb movements like those involved in locomotion. We developed an MR compatible pedaling device and recorded human brain activity associated with rhythmic, alternating flexion and extension of the lower extremities. Ten volunteers pedaled at 30 RPM while recording fMRI signals in a GE 3T short bore MR scanner. We utilized a block design consisting of 3 runs of pedaling, each lasting 4 min. In a single run, subjects pedaled for 30 s and then rested for 30 s. This sequence was repeated 4 times. Conventional fMRI processing techniques, that correlate the entire BOLD signal with standard model, did not extract physiologically meaningful signal, likely due to magnetic field distortion caused by leg movement. Hence, we examined only the portion of the blood-oxygen-level dependent (BOLD) signal during movement-free periods. This technique takes advantage of the delayed nature of the BOLD signal and fits the falling portion of the signal after movement has stopped with a standard model. Using this approach, we observed physiologically plausible brain activity patterns associated with pedaling in the primary and secondary sensory and motor cortices and the cerebellum. To our knowledge, this is the first time that human brain activity associated with pedaling has been recorded with fMRI. This technique may be useful for advancing our understanding of supraspinal control of locomotor-like movements in health and disease.

  9. Unexpected global impact of VTA dopamine neuron activation as measured by opto-fMRI

    PubMed Central

    Lohani, Sweyta; Poplawsky, Alexander John; Kim, Seong-Gi; Moghaddam, Bita

    2016-01-01

    Dopamine neurons in the ventral tegmental area (VTA) are strongly implicated in cognitive and affective processing as well as in psychiatric disorders including schizophrenia, ADHD and substance abuse disorders. In human studies, dopamine-related functions are routinely assessed using functional magnetic resonance imaging (fMRI) measures of blood oxygenation-level dependent (BOLD) signals during the performance of dopamine-dependent tasks. There is, however, a critical void in our knowledge about if and how activation of VTA dopamine neurons specifically influences regional or global fMRI signals. Here we used optogenetics in Th::Cre rats to selectively stimulate VTA dopamine neurons while simultaneously measuring global hemodynamic changes using BOLD and cerebral blood volume-weighted (CBVw) fMRI. Phasic activation of VTA dopamine neurons increased BOLD and CBVw fMRI signals in VTA-innervated limbic regions, including the ventral striatum (nucleus accumbens). Surprisingly, basal ganglia regions that receive sparse or no VTA dopaminergic innervation, including the dorsal striatum and the globus pallidus, were also activated. In fact, the most prominent fMRI signal increase in the forebrain was observed in the dorsal striatum that is not traditionally associated with VTA dopamine neurotransmission. These data establish causation between phasic activation of VTA dopamine neurons and global fMRI signals. They further suggest that mesolimbic and non-limbic basal ganglia dopamine circuits are functionally connected and, thus, provide a potential novel framework for understanding dopamine-dependent functions and interpreting data obtained from human fMRI studies. PMID:27457809

  10. Self-Regulation of Amygdala Activation Using Real-Time fMRI Neurofeedback

    PubMed Central

    Phillips, Raquel; Alvarez, Ruben P.; Simmons, W. Kyle; Bellgowan, Patrick; Drevets, Wayne C.; Bodurka, Jerzy

    2011-01-01

    Real-time functional magnetic resonance imaging (rtfMRI) with neurofeedback allows investigation of human brain neuroplastic changes that arise as subjects learn to modulate neurophysiological function using real-time feedback regarding their own hemodynamic responses to stimuli. We investigated the feasibility of training healthy humans to self-regulate the hemodynamic activity of the amygdala, which plays major roles in emotional processing. Participants in the experimental group were provided with ongoing information about the blood oxygen level dependent (BOLD) activity in the left amygdala (LA) and were instructed to raise the BOLD rtfMRI signal by contemplating positive autobiographical memories. A control group was assigned the same task but was instead provided with sham feedback from the left horizontal segment of the intraparietal sulcus (HIPS) region. In the LA, we found a significant BOLD signal increase due to rtfMRI neurofeedback training in the experimental group versus the control group. This effect persisted during the Transfer run without neurofeedback. For the individual subjects in the experimental group the training effect on the LA BOLD activity correlated inversely with scores on the Difficulty Identifying Feelings subscale of the Toronto Alexithymia Scale. The whole brain data analysis revealed significant differences for Happy Memories versus Rest condition between the experimental and control groups. Functional connectivity analysis of the amygdala network revealed significant widespread correlations in a fronto-temporo-limbic network. Additionally, we identified six regions — right medial frontal polar cortex, bilateral dorsomedial prefrontal cortex, left anterior cingulate cortex, and bilateral superior frontal gyrus — where the functional connectivity with the LA increased significantly across the rtfMRI neurofeedback runs and the Transfer run. The findings demonstrate that healthy subjects can learn to regulate their amygdala

  11. Ketamine-induced brain activation in awake female nonhuman primates: a translational functional imaging model.

    PubMed

    Maltbie, Eric; Gopinath, Kaundinya; Urushino, Naoko; Kempf, Doty; Howell, Leonard

    2016-03-01

    There is significant interest in the NMDA receptor antagonist ketamine due to its efficacy in treating depressive disorders and its induction of psychotic-like symptoms that make it a useful tool for modeling psychosis. The present study extends the successful development of an apparatus and methodology to conduct pharmacological MRI studies in awake rhesus monkeys in order to evaluate the CNS effects of ketamine. Functional MRI scans were conducted in four awake adult female rhesus monkeys during sub-anesthetic intravenous (i.v.) infusions of ketamine (0.345 mg/kg bolus followed by 0.256 mg/kg/h constant infusion) with and without risperidone pretreatment (0.06 mg/kg). Statistical parametric maps of ketamine-induced blood oxygenation level-dependent (BOLD) activation were obtained with appropriate general linear regression models (GLMs) incorporating motion and hemodynamics of ketamine infusion. Ketamine infusion induced and sustained robust BOLD activation in a number of cortical and subcortical regions, including the thalamus, cingulate gyrus, and supplementary motor area. Pretreatment with the antipsychotic drug risperidone markedly blunted ketamine-induced activation in many brain areas. The results are remarkably similar to human imaging studies showing ketamine-induced BOLD activation in many of the same brain areas, and pretreatment with risperidone or another antipsychotic blunting the ketamine response to a similar extent. The strong concordance of the functional imaging data in humans with these results from nonhuman primates highlights the translational value of the model and provides an excellent avenue for future research examining the CNS effects of ketamine. This model may also be a useful tool for evaluating the efficacy of novel antipsychotic drugs.

  12. Lisdexamfetamine Effects on Executive Activation and Neurochemistry in Menopausal Women with Executive Function Difficulties.

    PubMed

    Shanmugan, Sheila; Loughead, James; Nanga, Ravi Prakash Reddy; Elliott, Mark; Hariharan, Hari; Appleby, Dina; Kim, Deborah; Ruparel, Kosha; Reddy, Ravinder; Brown, Thomas E; Epperson, C Neill

    2017-01-01

    Many women with no history of executive dysfunction report difficulties in this domain during the menopause transition. Lisdexamfetamine (LDX) has been suggested to be a safe and effective treatment option for these women. However, the mechanism by which LDX improves executive functioning in these women is not known. Here we investigated the effects of LDX on brain activation and neurochemistry, hypothesizing that LDX would be associated with increased activation and decreased glutamate in executive regions. Fourteen women underwent multimodal neuroimaging at 7T at three time points in this baseline-corrected, double-blind, placebo-controlled, crossover study. Effects of LDX on symptom severity, blood-oxygen-level-dependent (BOLD) signal, and dorsolateral prefrontal cortex (DLPFC) glutamate+glutamine (Glx) were measured using a clinician-administered questionnaire, fMRI during performance of a fractal n-back task, and (1)H-MRS, respectively. The effect of treatment (LDX minus baseline vs placebo minus baseline) on these behavioral and neural markers of executive function was examined using repeated measures mixed effects models. LDX treatment was associated with decreased symptom severity, increased activation in the insula and DLPFC, and decreased DLPFC Glx. In addition, the magnitude of LDX-induced improvement in symptom severity predicted both direction and magnitude of LDX-induced change in insular and DLPFC activation. Moreover, symptom severity was positively correlated with Glx concentration in the left DLPFC at baseline. These findings provide novel evidence that the neural mechanisms by which LDX acts to improve self-reported executive functioning in healthy menopausal women with midlife onset of executive difficulties include modulation of insular and DLPFC recruitment as well as decrease in DLPFC Glx concentration.

  13. List 9 - Active CERCLIS Sites:

    EPA Pesticide Factsheets

    The List 9 displays the sequence of activities undertaken at active CERCLIS sites. An active site is one at which site assessment, removal, remedial, enforcement, cost recovery, or oversight activities are being planned or conducted.

  14. Agitated Active Region

    NASA Image and Video Library

    2016-10-11

    An active region just rotating into view gave us a perfect view of the tussle of magnetic field lines above it (Oct. 10-11, 2016). The particles spiraling along the magnetic field lines become visible in extreme ultraviolet light, helping us to see the struggle going on. There were no eruptions during this period, although active regions are usually the source for solar storms. The video clip covers just one day's worth of activity. Movies are available at http://photojournal.jpl.nasa.gov/catalog/PIA21109

  15. Physics of solar activity

    NASA Technical Reports Server (NTRS)

    Sturrock, Peter A.

    1993-01-01

    The aim of the research activity was to increase our understanding of solar activity through data analysis, theoretical analysis, and computer modeling. Because the research subjects were diverse and many researchers were supported by this grant, a select few key areas of research are described in detail. Areas of research include: (1) energy storage and force-free magnetic field; (2) energy release and particle acceleration; (3) radiation by nonthermal electrons; (4) coronal loops; (5) flare classification; (6) longitude distributions of flares; (7) periodicities detected in the solar activity; (8) coronal heating and related problems; and (9) plasma processes.

  16. Chewing-induced regional brain activity in edentulous patients who received mandibular implant-supported overdentures: a preliminary report.

    PubMed

    Kimoto, Katsuhiko; Ono, Yumie; Tachibana, Atsumichi; Hirano, Yoshiyuki; Otsuka, Takero; Ohno, Akinori; Yamaya, Katsuhiko; Obata, Takayuki; Onozuka, Minoru

    2011-04-01

    We used functional magnetic resonance imaging (fMRI) to investigate the change in brain regional activity during gum chewing when edentulous subjects switched from mandibular complete dentures to implant-supported removable overdentures. Four edentulous patients (3 males and 1 female, aged 64 to 79 years) participated in the study. All subjects received a set of new maxillary and mandibular complete dentures (CD), followed by a maxillary complete denture and a new mandibular implant-supported removable overdentures (IOD). A 3-T fMRI scanner produced images of the regional brain activity for each subject that showed changes in the blood-oxygenation-level-dependent (BOLD) contrast in the axial orientation during gum-chewing with CD and IOD. Region-of-interest analysis showed that IOD treatment significantly suppressed chewing-induced brain activity in the prefrontal cortex. The chewing-induced brain activities in the primary sensorimotor cortex and cerebellum tended to decrease with IOD treatment, however they did not reach to significance level. There was no change in brain activity in the supplementary motor area, thalamus and insula between gum chewing with CD and IOD. Group comparison using statistical parametrical mapping further showed that, within the prefrontal cortex, the neural activity of the frontal pole significantly decreased during gum-chewing with IOD when compared to that with CD (P<0.05). Despite the limitation of a small sample size, these results suggest that the gum-chewing task in elderly edentulous patients resulted in differential neural activity in the frontal pole within the prefrontal cortex between the 2 prosthodontic therapies-mandibular CD and IOD. Copyright © 2010 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  17. Aberrant Dependence of Default Mode/Central Executive Network Interactions on Anterior Insular Salience Network Activity in Schizophrenia

    PubMed Central

    Sorg, Christian

    2014-01-01

    In schizophrenia, consistent structural and functional changes have been demonstrated for the insula including aberrant salience processing, which is critical for psychosis. Interactions within and across default mode and central executive network (DMN, CEN) are impaired in schizophrenia. The question arises whether these 2 types of changes are related. Recently, the anterior insula has been demonstrated to control DMN/CEN interactions. We hypothesized that aberrant insula and DMN/CEN activity in schizophrenia is associated with an impaired dependence of DMN/CEN interactions on anterior insular salience network (SN) activity. Eighteen patients with schizophrenia during psychosis and 20 healthy controls were studied by resting-state-fMRI and psychometric examination. High-model-order independent component analysis of fMRI data revealed spatiotemporal patterns of synchronized ongoing blood-oxygenation-level-dependent (BOLD) activity including SN, DMN, and CEN. Scores of functional and time-lagged connectivity across networks’ time courses were calculated. Connectivity scores and spatial network maps were compared between groups and related with patients’ hallucination and delusion severity. Spatial BOLD-synchronicity was altered in patients’ SN, DMN, and CEN, including decreased activity in the right anterior insula (rAI). Patients’ functional connectivity between DMN and CEN was increased and related with hallucinations severity. Importantly, patients’ time-lagged connectivity between SN and DMN/CEN was reduced, and decreased rAI activity of the SN was associated with both hallucinations and increased functional connectivity between DMN and CEN. Data provide evidence for an aberrant dependence of DMN/CEN interactions on anterior insular SN activity, linking impaired insula, DMN, CEN activity, and psychosis in schizophrenia. PMID:23519021

  18. Immunizations: Active vs. Passive

    MedlinePlus

    ... a few weeks before the antibodies are worn down and removed from the bloodstream. By contrast, active immunizations can produce antibodies that last a lifetime. Last Updated 11/21/2015 Source Immunizations & Infectious Diseases: An Informed Parent's ...

  19. Active at Any Size

    MedlinePlus

    ... online and can download them to a computer, smart phone, or other device. These types of activities may ... to track your progress using a computer or smart phone or other mobile device. Devices you can wear, ...

  20. Balance Food and Activity

    MedlinePlus

    ... eNewsletters Calendar Balance Food and Activity What is Energy Balance? Energy is another word for "calories." Your ... adults, fewer calories are needed at older ages. Energy Balance in Real Life Think of it as ...